Index: linux-3.4/mm/slab.c
===================================================================
--- linux-3.4.orig/mm/slab.c
+++ linux-3.4/mm/slab.c
@@ -116,6 +116,7 @@
 #include	<linux/kmemcheck.h>
 #include	<linux/memory.h>
 #include	<linux/prefetch.h>
+#include	<linux/locallock.h>
 
 #include	<asm/cacheflush.h>
 #include	<asm/tlbflush.h>
@@ -611,6 +612,12 @@ int slab_is_available(void)
 	return g_cpucache_up >= EARLY;
 }
 
+/*
+ * Guard access to the cache-chain.
+ */
+static DEFINE_MUTEX(cache_chain_mutex);
+static struct list_head cache_chain;
+
 #ifdef CONFIG_LOCKDEP
 
 /*
@@ -672,38 +679,41 @@ static void slab_set_debugobj_lock_class
 		slab_set_debugobj_lock_classes_node(cachep, node);
 }
 
-static void init_node_lock_keys(int q)
+static void init_lock_keys(struct kmem_cache *cachep, int node)
 {
-	struct cache_sizes *s = malloc_sizes;
+	struct kmem_list3 *l3;
 
 	if (g_cpucache_up < LATE)
 		return;
 
-	for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
-		struct kmem_list3 *l3;
+	l3 = cachep->nodelists[node];
+	if (!l3 || OFF_SLAB(cachep))
+		return;
 
-		l3 = s->cs_cachep->nodelists[q];
-		if (!l3 || OFF_SLAB(s->cs_cachep))
-			continue;
+	slab_set_lock_classes(cachep, &on_slab_l3_key, &on_slab_alc_key, node);
+}
 
-		slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key,
-				&on_slab_alc_key, q);
-	}
+static void init_node_lock_keys(int node)
+{
+	struct kmem_cache *cachep;
+
+	list_for_each_entry(cachep, &cache_chain, next)
+		init_lock_keys(cachep, node);
 }
 
-static inline void init_lock_keys(void)
+static inline void init_cachep_lock_keys(struct kmem_cache *cachep)
 {
 	int node;
 
 	for_each_node(node)
-		init_node_lock_keys(node);
+		init_lock_keys(cachep, node);
 }
 #else
-static void init_node_lock_keys(int q)
+static void init_node_lock_keys(int node)
 {
 }
 
-static inline void init_lock_keys(void)
+static void init_cachep_lock_keys(struct kmem_cache *cachep)
 {
 }
 
@@ -716,19 +726,67 @@ static void slab_set_debugobj_lock_class
 }
 #endif
 
+static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
+static DEFINE_PER_CPU(struct list_head, slab_free_list);
+static DEFINE_LOCAL_IRQ_LOCK(slab_lock);
+
+#ifndef CONFIG_PREEMPT_RT_BASE
+# define slab_on_each_cpu(func, cp)	on_each_cpu(func, cp, 1)
+#else
 /*
- * Guard access to the cache-chain.
+ * execute func() for all CPUs. On PREEMPT_RT we dont actually have
+ * to run on the remote CPUs - we only have to take their CPU-locks.
+ * (This is a rare operation, so cacheline bouncing is not an issue.)
  */
-static DEFINE_MUTEX(cache_chain_mutex);
-static struct list_head cache_chain;
+static void
+slab_on_each_cpu(void (*func)(void *arg, int this_cpu), void *arg)
+{
+	unsigned int i;
 
-static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
+	for_each_online_cpu(i)
+		func(arg, i);
+}
+#endif
+
+static void free_delayed(struct list_head *h)
+{
+	while(!list_empty(h)) {
+		struct page *page = list_first_entry(h, struct page, lru);
+
+		list_del(&page->lru);
+		__free_pages(page, page->index);
+	}
+}
+
+static void unlock_l3_and_free_delayed(spinlock_t *list_lock)
+{
+	LIST_HEAD(tmp);
+
+	list_splice_init(&__get_cpu_var(slab_free_list), &tmp);
+	local_spin_unlock_irq(slab_lock, list_lock);
+	free_delayed(&tmp);
+}
+
+static void unlock_slab_and_free_delayed(unsigned long flags)
+{
+	LIST_HEAD(tmp);
+
+	list_splice_init(&__get_cpu_var(slab_free_list), &tmp);
+	local_unlock_irqrestore(slab_lock, flags);
+	free_delayed(&tmp);
+}
 
 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
 {
 	return cachep->array[smp_processor_id()];
 }
 
+static inline struct array_cache *cpu_cache_get_on_cpu(struct kmem_cache *cachep,
+						       int cpu)
+{
+	return cachep->array[cpu];
+}
+
 static inline struct kmem_cache *__find_general_cachep(size_t size,
 							gfp_t gfpflags)
 {
@@ -1077,9 +1135,10 @@ static void reap_alien(struct kmem_cache
 	if (l3->alien) {
 		struct array_cache *ac = l3->alien[node];
 
-		if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
+		if (ac && ac->avail &&
+		    local_spin_trylock_irq(slab_lock, &ac->lock)) {
 			__drain_alien_cache(cachep, ac, node);
-			spin_unlock_irq(&ac->lock);
+			local_spin_unlock_irq(slab_lock, &ac->lock);
 		}
 	}
 }
@@ -1094,9 +1153,9 @@ static void drain_alien_cache(struct kme
 	for_each_online_node(i) {
 		ac = alien[i];
 		if (ac) {
-			spin_lock_irqsave(&ac->lock, flags);
+			local_spin_lock_irqsave(slab_lock, &ac->lock, flags);
 			__drain_alien_cache(cachep, ac, i);
-			spin_unlock_irqrestore(&ac->lock, flags);
+			local_spin_unlock_irqrestore(slab_lock, &ac->lock, flags);
 		}
 	}
 }
@@ -1175,11 +1234,11 @@ static int init_cache_nodelists_node(int
 			cachep->nodelists[node] = l3;
 		}
 
-		spin_lock_irq(&cachep->nodelists[node]->list_lock);
+		local_spin_lock_irq(slab_lock, &cachep->nodelists[node]->list_lock);
 		cachep->nodelists[node]->free_limit =
 			(1 + nr_cpus_node(node)) *
 			cachep->batchcount + cachep->num;
-		spin_unlock_irq(&cachep->nodelists[node]->list_lock);
+		local_spin_unlock_irq(slab_lock, &cachep->nodelists[node]->list_lock);
 	}
 	return 0;
 }
@@ -1204,7 +1263,7 @@ static void __cpuinit cpuup_canceled(lon
 		if (!l3)
 			goto free_array_cache;
 
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 
 		/* Free limit for this kmem_list3 */
 		l3->free_limit -= cachep->batchcount;
@@ -1212,7 +1271,7 @@ static void __cpuinit cpuup_canceled(lon
 			free_block(cachep, nc->entry, nc->avail, node);
 
 		if (!cpumask_empty(mask)) {
-			spin_unlock_irq(&l3->list_lock);
+			unlock_l3_and_free_delayed(&l3->list_lock);
 			goto free_array_cache;
 		}
 
@@ -1226,7 +1285,7 @@ static void __cpuinit cpuup_canceled(lon
 		alien = l3->alien;
 		l3->alien = NULL;
 
-		spin_unlock_irq(&l3->list_lock);
+		unlock_l3_and_free_delayed(&l3->list_lock);
 
 		kfree(shared);
 		if (alien) {
@@ -1300,7 +1359,7 @@ static int __cpuinit cpuup_prepare(long 
 		l3 = cachep->nodelists[node];
 		BUG_ON(!l3);
 
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 		if (!l3->shared) {
 			/*
 			 * We are serialised from CPU_DEAD or
@@ -1315,7 +1374,7 @@ static int __cpuinit cpuup_prepare(long 
 			alien = NULL;
 		}
 #endif
-		spin_unlock_irq(&l3->list_lock);
+		local_spin_unlock_irq(slab_lock, &l3->list_lock);
 		kfree(shared);
 		free_alien_cache(alien);
 		if (cachep->flags & SLAB_DEBUG_OBJECTS)
@@ -1506,6 +1565,10 @@ void __init kmem_cache_init(void)
 	if (num_possible_nodes() == 1)
 		use_alien_caches = 0;
 
+	local_irq_lock_init(slab_lock);
+	for_each_possible_cpu(i)
+		INIT_LIST_HEAD(&per_cpu(slab_free_list, i));
+
 	for (i = 0; i < NUM_INIT_LISTS; i++) {
 		kmem_list3_init(&initkmem_list3[i]);
 		if (i < MAX_NUMNODES)
@@ -1685,14 +1748,13 @@ void __init kmem_cache_init_late(void)
 
 	g_cpucache_up = LATE;
 
-	/* Annotate slab for lockdep -- annotate the malloc caches */
-	init_lock_keys();
-
 	/* 6) resize the head arrays to their final sizes */
 	mutex_lock(&cache_chain_mutex);
-	list_for_each_entry(cachep, &cache_chain, next)
+	list_for_each_entry(cachep, &cache_chain, next) {
+		init_cachep_lock_keys(cachep);
 		if (enable_cpucache(cachep, GFP_NOWAIT))
 			BUG();
+	}
 	mutex_unlock(&cache_chain_mutex);
 
 	/* Done! */
@@ -1834,12 +1896,14 @@ static void *kmem_getpages(struct kmem_c
 /*
  * Interface to system's page release.
  */
-static void kmem_freepages(struct kmem_cache *cachep, void *addr)
+static void kmem_freepages(struct kmem_cache *cachep, void *addr, bool delayed)
 {
 	unsigned long i = (1 << cachep->gfporder);
-	struct page *page = virt_to_page(addr);
+	struct page *page, *basepage = virt_to_page(addr);
 	const unsigned long nr_freed = i;
 
+	page = basepage;
+
 	kmemcheck_free_shadow(page, cachep->gfporder);
 
 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
@@ -1855,7 +1919,13 @@ static void kmem_freepages(struct kmem_c
 	}
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += nr_freed;
-	free_pages((unsigned long)addr, cachep->gfporder);
+
+	if (!delayed) {
+		free_pages((unsigned long)addr, cachep->gfporder);
+	} else {
+		basepage->index = cachep->gfporder;
+		list_add(&basepage->lru, &__get_cpu_var(slab_free_list));
+	}
 }
 
 static void kmem_rcu_free(struct rcu_head *head)
@@ -1863,7 +1933,7 @@ static void kmem_rcu_free(struct rcu_hea
 	struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
 	struct kmem_cache *cachep = slab_rcu->cachep;
 
-	kmem_freepages(cachep, slab_rcu->addr);
+	kmem_freepages(cachep, slab_rcu->addr, false);
 	if (OFF_SLAB(cachep))
 		kmem_cache_free(cachep->slabp_cache, slab_rcu);
 }
@@ -2082,7 +2152,8 @@ static void slab_destroy_debugcheck(stru
  * Before calling the slab must have been unlinked from the cache.  The
  * cache-lock is not held/needed.
  */
-static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
+static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp,
+			 bool delayed)
 {
 	void *addr = slabp->s_mem - slabp->colouroff;
 
@@ -2095,7 +2166,7 @@ static void slab_destroy(struct kmem_cac
 		slab_rcu->addr = addr;
 		call_rcu(&slab_rcu->head, kmem_rcu_free);
 	} else {
-		kmem_freepages(cachep, addr);
+		kmem_freepages(cachep, addr, delayed);
 		if (OFF_SLAB(cachep))
 			kmem_cache_free(cachep->slabp_cache, slabp);
 	}
@@ -2544,6 +2615,8 @@ kmem_cache_create (const char *name, siz
 		slab_set_debugobj_lock_classes(cachep);
 	}
 
+	init_cachep_lock_keys(cachep);
+
 	/* cache setup completed, link it into the list */
 	list_add(&cachep->next, &cache_chain);
 oops:
@@ -2561,7 +2634,7 @@ EXPORT_SYMBOL(kmem_cache_create);
 #if DEBUG
 static void check_irq_off(void)
 {
-	BUG_ON(!irqs_disabled());
+	BUG_ON_NONRT(!irqs_disabled());
 }
 
 static void check_irq_on(void)
@@ -2596,26 +2669,43 @@ static void drain_array(struct kmem_cach
 			struct array_cache *ac,
 			int force, int node);
 
-static void do_drain(void *arg)
+static void __do_drain(void *arg, unsigned int cpu)
 {
 	struct kmem_cache *cachep = arg;
 	struct array_cache *ac;
-	int node = numa_mem_id();
+	int node = cpu_to_mem(cpu);
 
-	check_irq_off();
-	ac = cpu_cache_get(cachep);
+	ac = cpu_cache_get_on_cpu(cachep, cpu);
 	spin_lock(&cachep->nodelists[node]->list_lock);
 	free_block(cachep, ac->entry, ac->avail, node);
 	spin_unlock(&cachep->nodelists[node]->list_lock);
 	ac->avail = 0;
 }
 
+#ifndef CONFIG_PREEMPT_RT_BASE
+static void do_drain(void *arg)
+{
+	__do_drain(arg, smp_processor_id());
+}
+#else
+static void do_drain(void *arg, int cpu)
+{
+	LIST_HEAD(tmp);
+
+	spin_lock_irq(&per_cpu(slab_lock, cpu).lock);
+	__do_drain(arg, cpu);
+	list_splice_init(&per_cpu(slab_free_list, cpu), &tmp);
+	spin_unlock_irq(&per_cpu(slab_lock, cpu).lock);
+	free_delayed(&tmp);
+}
+#endif
+
 static void drain_cpu_caches(struct kmem_cache *cachep)
 {
 	struct kmem_list3 *l3;
 	int node;
 
-	on_each_cpu(do_drain, cachep, 1);
+	slab_on_each_cpu(do_drain, cachep);
 	check_irq_on();
 	for_each_online_node(node) {
 		l3 = cachep->nodelists[node];
@@ -2646,10 +2736,10 @@ static int drain_freelist(struct kmem_ca
 	nr_freed = 0;
 	while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
 
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 		p = l3->slabs_free.prev;
 		if (p == &l3->slabs_free) {
-			spin_unlock_irq(&l3->list_lock);
+			local_spin_unlock_irq(slab_lock, &l3->list_lock);
 			goto out;
 		}
 
@@ -2663,8 +2753,8 @@ static int drain_freelist(struct kmem_ca
 		 * to the cache.
 		 */
 		l3->free_objects -= cache->num;
-		spin_unlock_irq(&l3->list_lock);
-		slab_destroy(cache, slabp);
+		local_spin_unlock_irq(slab_lock, &l3->list_lock);
+		slab_destroy(cache, slabp, false);
 		nr_freed++;
 	}
 out:
@@ -2958,7 +3048,7 @@ static int cache_grow(struct kmem_cache 
 	offset *= cachep->colour_off;
 
 	if (local_flags & __GFP_WAIT)
-		local_irq_enable();
+		local_unlock_irq(slab_lock);
 
 	/*
 	 * The test for missing atomic flag is performed here, rather than
@@ -2988,7 +3078,7 @@ static int cache_grow(struct kmem_cache 
 	cache_init_objs(cachep, slabp);
 
 	if (local_flags & __GFP_WAIT)
-		local_irq_disable();
+		local_lock_irq(slab_lock);
 	check_irq_off();
 	spin_lock(&l3->list_lock);
 
@@ -2999,10 +3089,10 @@ static int cache_grow(struct kmem_cache 
 	spin_unlock(&l3->list_lock);
 	return 1;
 opps1:
-	kmem_freepages(cachep, objp);
+	kmem_freepages(cachep, objp, false);
 failed:
 	if (local_flags & __GFP_WAIT)
-		local_irq_disable();
+		local_lock_irq(slab_lock);
 	return 0;
 }
 
@@ -3396,11 +3486,11 @@ retry:
 		 * set and go into memory reserves if necessary.
 		 */
 		if (local_flags & __GFP_WAIT)
-			local_irq_enable();
+			local_unlock_irq(slab_lock);
 		kmem_flagcheck(cache, flags);
 		obj = kmem_getpages(cache, local_flags, numa_mem_id());
 		if (local_flags & __GFP_WAIT)
-			local_irq_disable();
+			local_lock_irq(slab_lock);
 		if (obj) {
 			/*
 			 * Insert into the appropriate per node queues
@@ -3518,7 +3608,7 @@ __cache_alloc_node(struct kmem_cache *ca
 		return NULL;
 
 	cache_alloc_debugcheck_before(cachep, flags);
-	local_irq_save(save_flags);
+	local_lock_irqsave(slab_lock, save_flags);
 
 	if (nodeid == NUMA_NO_NODE)
 		nodeid = slab_node;
@@ -3543,7 +3633,7 @@ __cache_alloc_node(struct kmem_cache *ca
 	/* ___cache_alloc_node can fall back to other nodes */
 	ptr = ____cache_alloc_node(cachep, flags, nodeid);
   out:
-	local_irq_restore(save_flags);
+	local_unlock_irqrestore(slab_lock, save_flags);
 	ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
 	kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
 				 flags);
@@ -3603,9 +3693,9 @@ __cache_alloc(struct kmem_cache *cachep,
 		return NULL;
 
 	cache_alloc_debugcheck_before(cachep, flags);
-	local_irq_save(save_flags);
+	local_lock_irqsave(slab_lock, save_flags);
 	objp = __do_cache_alloc(cachep, flags);
-	local_irq_restore(save_flags);
+	local_unlock_irqrestore(slab_lock, save_flags);
 	objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
 	kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags,
 				 flags);
@@ -3653,7 +3743,7 @@ static void free_block(struct kmem_cache
 				 * a different cache, refer to comments before
 				 * alloc_slabmgmt.
 				 */
-				slab_destroy(cachep, slabp);
+				slab_destroy(cachep, slabp, true);
 			} else {
 				list_add(&slabp->list, &l3->slabs_free);
 			}
@@ -3915,12 +4005,12 @@ void kmem_cache_free(struct kmem_cache *
 {
 	unsigned long flags;
 
-	local_irq_save(flags);
 	debug_check_no_locks_freed(objp, obj_size(cachep));
 	if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
 		debug_check_no_obj_freed(objp, obj_size(cachep));
+	local_lock_irqsave(slab_lock, flags);
 	__cache_free(cachep, objp, __builtin_return_address(0));
-	local_irq_restore(flags);
+	unlock_slab_and_free_delayed(flags);
 
 	trace_kmem_cache_free(_RET_IP_, objp);
 }
@@ -3944,13 +4034,13 @@ void kfree(const void *objp)
 
 	if (unlikely(ZERO_OR_NULL_PTR(objp)))
 		return;
-	local_irq_save(flags);
 	kfree_debugcheck(objp);
 	c = virt_to_cache(objp);
 	debug_check_no_locks_freed(objp, obj_size(c));
 	debug_check_no_obj_freed(objp, obj_size(c));
+	local_lock_irqsave(slab_lock, flags);
 	__cache_free(c, (void *)objp, __builtin_return_address(0));
-	local_irq_restore(flags);
+	unlock_slab_and_free_delayed(flags);
 }
 EXPORT_SYMBOL(kfree);
 
@@ -3993,7 +4083,7 @@ static int alloc_kmemlist(struct kmem_ca
 		if (l3) {
 			struct array_cache *shared = l3->shared;
 
-			spin_lock_irq(&l3->list_lock);
+			local_spin_lock_irq(slab_lock, &l3->list_lock);
 
 			if (shared)
 				free_block(cachep, shared->entry,
@@ -4006,7 +4096,8 @@ static int alloc_kmemlist(struct kmem_ca
 			}
 			l3->free_limit = (1 + nr_cpus_node(node)) *
 					cachep->batchcount + cachep->num;
-			spin_unlock_irq(&l3->list_lock);
+			unlock_l3_and_free_delayed(&l3->list_lock);
+
 			kfree(shared);
 			free_alien_cache(new_alien);
 			continue;
@@ -4053,17 +4144,30 @@ struct ccupdate_struct {
 	struct array_cache *new[0];
 };
 
-static void do_ccupdate_local(void *info)
+static void __do_ccupdate_local(void *info, int cpu)
 {
 	struct ccupdate_struct *new = info;
 	struct array_cache *old;
 
-	check_irq_off();
-	old = cpu_cache_get(new->cachep);
+	old = cpu_cache_get_on_cpu(new->cachep, cpu);
+
+	new->cachep->array[cpu] = new->new[cpu];
+	new->new[cpu] = old;
+}
 
-	new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
-	new->new[smp_processor_id()] = old;
+#ifndef CONFIG_PREEMPT_RT_BASE
+static void do_ccupdate_local(void *info)
+{
+	__do_ccupdate_local(info, smp_processor_id());
 }
+#else
+static void do_ccupdate_local(void *info, int cpu)
+{
+	spin_lock_irq(&per_cpu(slab_lock, cpu).lock);
+	__do_ccupdate_local(info, cpu);
+	spin_unlock_irq(&per_cpu(slab_lock, cpu).lock);
+}
+#endif
 
 /* Always called with the cache_chain_mutex held */
 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
@@ -4089,7 +4193,7 @@ static int do_tune_cpucache(struct kmem_
 	}
 	new->cachep = cachep;
 
-	on_each_cpu(do_ccupdate_local, (void *)new, 1);
+	slab_on_each_cpu(do_ccupdate_local, (void *)new);
 
 	check_irq_on();
 	cachep->batchcount = batchcount;
@@ -4100,9 +4204,11 @@ static int do_tune_cpucache(struct kmem_
 		struct array_cache *ccold = new->new[i];
 		if (!ccold)
 			continue;
-		spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
+		local_spin_lock_irq(slab_lock,
+				    &cachep->nodelists[cpu_to_mem(i)]->list_lock);
 		free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
-		spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
+
+		unlock_l3_and_free_delayed(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
 		kfree(ccold);
 	}
 	kfree(new);
@@ -4178,7 +4284,7 @@ static void drain_array(struct kmem_cach
 	if (ac->touched && !force) {
 		ac->touched = 0;
 	} else {
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 		if (ac->avail) {
 			tofree = force ? ac->avail : (ac->limit + 4) / 5;
 			if (tofree > ac->avail)
@@ -4188,7 +4294,7 @@ static void drain_array(struct kmem_cach
 			memmove(ac->entry, &(ac->entry[tofree]),
 				sizeof(void *) * ac->avail);
 		}
-		spin_unlock_irq(&l3->list_lock);
+		local_spin_unlock_irq(slab_lock, &l3->list_lock);
 	}
 }
 
@@ -4327,7 +4433,7 @@ static int s_show(struct seq_file *m, vo
 			continue;
 
 		check_irq_on();
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 
 		list_for_each_entry(slabp, &l3->slabs_full, list) {
 			if (slabp->inuse != cachep->num && !error)
@@ -4352,7 +4458,7 @@ static int s_show(struct seq_file *m, vo
 		if (l3->shared)
 			shared_avail += l3->shared->avail;
 
-		spin_unlock_irq(&l3->list_lock);
+		local_spin_unlock_irq(slab_lock, &l3->list_lock);
 	}
 	num_slabs += active_slabs;
 	num_objs = num_slabs * cachep->num;
@@ -4581,13 +4687,13 @@ static int leaks_show(struct seq_file *m
 			continue;
 
 		check_irq_on();
-		spin_lock_irq(&l3->list_lock);
+		local_spin_lock_irq(slab_lock, &l3->list_lock);
 
 		list_for_each_entry(slabp, &l3->slabs_full, list)
 			handle_slab(n, cachep, slabp);
 		list_for_each_entry(slabp, &l3->slabs_partial, list)
 			handle_slab(n, cachep, slabp);
-		spin_unlock_irq(&l3->list_lock);
+		local_spin_unlock_irq(slab_lock, &l3->list_lock);
 	}
 	name = cachep->name;
 	if (n[0] == n[1]) {
Index: linux-3.4/arch/x86/kernel/kprobes.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/kprobes.c
+++ linux-3.4/arch/x86/kernel/kprobes.c
@@ -486,7 +486,6 @@ setup_singlestep(struct kprobe *p, struc
 		 * stepping.
 		 */
 		regs->ip = (unsigned long)p->ainsn.insn;
-		preempt_enable_no_resched();
 		return;
 	}
 #endif
Index: linux-3.4/arch/x86/kernel/hpet.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/hpet.c
+++ linux-3.4/arch/x86/kernel/hpet.c
@@ -8,6 +8,7 @@
 #include <linux/slab.h>
 #include <linux/hpet.h>
 #include <linux/init.h>
+#include <linux/dmi.h>
 #include <linux/cpu.h>
 #include <linux/pm.h>
 #include <linux/io.h>
@@ -570,6 +571,30 @@ static void init_one_hpet_msi_clockevent
 #define RESERVE_TIMERS 0
 #endif
 
+static int __init dmi_disable_hpet_msi(const struct dmi_system_id *d)
+{
+	hpet_msi_disable = 1;
+	return 0;
+}
+
+static struct dmi_system_id __initdata dmi_hpet_table[] = {
+	/*
+	 * MSI based per cpu timers lose interrupts when intel_idle()
+	 * is enabled - independent of the c-state. With idle=poll the
+	 * problem cannot be observed. We have no idea yet, whether
+	 * this is a W510 specific issue or a general chipset oddity.
+	 */
+	{
+	 .callback = dmi_disable_hpet_msi,
+	 .ident = "Lenovo W510",
+	 .matches = {
+		     DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		     DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad W510"),
+		     },
+	 },
+	{}
+};
+
 static void hpet_msi_capability_lookup(unsigned int start_timer)
 {
 	unsigned int id;
@@ -577,6 +602,8 @@ static void hpet_msi_capability_lookup(u
 	unsigned int num_timers_used = 0;
 	int i;
 
+	dmi_check_system(dmi_hpet_table);
+
 	if (hpet_msi_disable)
 		return;
 
Index: linux-3.4/block/blk-core.c
===================================================================
--- linux-3.4.orig/block/blk-core.c
+++ linux-3.4/block/blk-core.c
@@ -237,7 +237,7 @@ EXPORT_SYMBOL(blk_delay_queue);
  **/
 void blk_start_queue(struct request_queue *q)
 {
-	WARN_ON(!irqs_disabled());
+	WARN_ON_NONRT(!irqs_disabled());
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
 	__blk_run_queue(q);
@@ -302,7 +302,11 @@ void __blk_run_queue(struct request_queu
 {
 	if (unlikely(blk_queue_stopped(q)))
 		return;
-
+	/*
+	 * q->request_fn() can drop q->queue_lock and reenable
+	 * interrupts, but must return with q->queue_lock held and
+	 * interrupts disabled.
+	 */
 	q->request_fn(q);
 }
 EXPORT_SYMBOL(__blk_run_queue);
@@ -2779,11 +2783,11 @@ static void queue_unplugged(struct reque
 	 * this lock).
 	 */
 	if (from_schedule) {
-		spin_unlock(q->queue_lock);
+		spin_unlock_irq(q->queue_lock);
 		blk_run_queue_async(q);
 	} else {
 		__blk_run_queue(q);
-		spin_unlock(q->queue_lock);
+		spin_unlock_irq(q->queue_lock);
 	}
 
 }
@@ -2809,7 +2813,6 @@ static void flush_plug_callbacks(struct 
 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 {
 	struct request_queue *q;
-	unsigned long flags;
 	struct request *rq;
 	LIST_HEAD(list);
 	unsigned int depth;
@@ -2830,11 +2833,6 @@ void blk_flush_plug_list(struct blk_plug
 	q = NULL;
 	depth = 0;
 
-	/*
-	 * Save and disable interrupts here, to avoid doing it for every
-	 * queue lock we have to take.
-	 */
-	local_irq_save(flags);
 	while (!list_empty(&list)) {
 		rq = list_entry_rq(list.next);
 		list_del_init(&rq->queuelist);
@@ -2847,7 +2845,7 @@ void blk_flush_plug_list(struct blk_plug
 				queue_unplugged(q, depth, from_schedule);
 			q = rq->q;
 			depth = 0;
-			spin_lock(q->queue_lock);
+			spin_lock_irq(q->queue_lock);
 		}
 
 		/*
@@ -2874,8 +2872,6 @@ void blk_flush_plug_list(struct blk_plug
 	 */
 	if (q)
 		queue_unplugged(q, depth, from_schedule);
-
-	local_irq_restore(flags);
 }
 
 void blk_finish_plug(struct blk_plug *plug)
Index: linux-3.4/kernel/sched/core.c
===================================================================
--- linux-3.4.orig/kernel/sched/core.c
+++ linux-3.4/kernel/sched/core.c
@@ -263,7 +263,11 @@ late_initcall(sched_init_debug);
  * Number of tasks to iterate in a single balance run.
  * Limited because this is done with IRQs disabled.
  */
+#ifndef CONFIG_PREEMPT_RT_FULL
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
+#else
+const_debug unsigned int sysctl_sched_nr_migrate = 8;
+#endif
 
 /*
  * period over which we average the RT time consumption, measured
@@ -480,6 +484,7 @@ static void init_rq_hrtick(struct rq *rq
 
 	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	rq->hrtick_timer.function = hrtick;
+	rq->hrtick_timer.irqsafe = 1;
 }
 #else	/* CONFIG_SCHED_HRTICK */
 static inline void hrtick_clear(struct rq *rq)
@@ -1169,7 +1174,8 @@ unsigned long wait_task_inactive(struct 
 		 * is actually now running somewhere else!
 		 */
 		while (task_running(rq, p)) {
-			if (match_state && unlikely(p->state != match_state))
+			if (match_state && unlikely(p->state != match_state)
+			    && unlikely(p->saved_state != match_state))
 				return 0;
 			cpu_relax();
 		}
@@ -1184,7 +1190,8 @@ unsigned long wait_task_inactive(struct 
 		running = task_running(rq, p);
 		on_rq = p->on_rq;
 		ncsw = 0;
-		if (!match_state || p->state == match_state)
+		if (!match_state || p->state == match_state
+		    || p->saved_state == match_state)
 			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
 		task_rq_unlock(rq, p, &flags);
 
@@ -1320,6 +1327,12 @@ out:
 		}
 	}
 
+	/*
+	 * Clear PF_THREAD_BOUND, otherwise we wreckage
+	 * migrate_disable/enable. See optimization for
+	 * PF_THREAD_BOUND tasks there.
+	 */
+	p->flags &= ~PF_THREAD_BOUND;
 	return dest_cpu;
 }
 
@@ -1399,10 +1412,6 @@ static void ttwu_activate(struct rq *rq,
 {
 	activate_task(rq, p, en_flags);
 	p->on_rq = 1;
-
-	/* if a worker is waking up, notify workqueue */
-	if (p->flags & PF_WQ_WORKER)
-		wq_worker_waking_up(p, cpu_of(rq));
 }
 
 /*
@@ -1585,8 +1594,27 @@ try_to_wake_up(struct task_struct *p, un
 
 	smp_wmb();
 	raw_spin_lock_irqsave(&p->pi_lock, flags);
-	if (!(p->state & state))
+	if (!(p->state & state)) {
+		/*
+		 * The task might be running due to a spinlock sleeper
+		 * wakeup. Check the saved state and set it to running
+		 * if the wakeup condition is true.
+		 */
+		if (!(wake_flags & WF_LOCK_SLEEPER)) {
+			if (p->saved_state & state) {
+				p->saved_state = TASK_RUNNING;
+				success = 1;
+			}
+		}
 		goto out;
+	}
+
+	/*
+	 * If this is a regular wakeup, then we can unconditionally
+	 * clear the saved state of a "lock sleeper".
+	 */
+	if (!(wake_flags & WF_LOCK_SLEEPER))
+		p->saved_state = TASK_RUNNING;
 
 	success = 1; /* we're going to change ->state */
 	cpu = task_cpu(p);
@@ -1642,40 +1670,6 @@ out:
 }
 
 /**
- * try_to_wake_up_local - try to wake up a local task with rq lock held
- * @p: the thread to be awakened
- *
- * Put @p on the run-queue if it's not already there. The caller must
- * ensure that this_rq() is locked, @p is bound to this_rq() and not
- * the current task.
- */
-static void try_to_wake_up_local(struct task_struct *p)
-{
-	struct rq *rq = task_rq(p);
-
-	BUG_ON(rq != this_rq());
-	BUG_ON(p == current);
-	lockdep_assert_held(&rq->lock);
-
-	if (!raw_spin_trylock(&p->pi_lock)) {
-		raw_spin_unlock(&rq->lock);
-		raw_spin_lock(&p->pi_lock);
-		raw_spin_lock(&rq->lock);
-	}
-
-	if (!(p->state & TASK_NORMAL))
-		goto out;
-
-	if (!p->on_rq)
-		ttwu_activate(rq, p, ENQUEUE_WAKEUP);
-
-	ttwu_do_wakeup(rq, p, 0);
-	ttwu_stat(p, smp_processor_id(), 0);
-out:
-	raw_spin_unlock(&p->pi_lock);
-}
-
-/**
  * wake_up_process - Wake up a specific process
  * @p: The process to be woken up.
  *
@@ -1692,6 +1686,18 @@ int wake_up_process(struct task_struct *
 }
 EXPORT_SYMBOL(wake_up_process);
 
+/**
+ * wake_up_lock_sleeper - Wake up a specific process blocked on a "sleeping lock"
+ * @p: The process to be woken up.
+ *
+ * Same as wake_up_process() above, but wake_flags=WF_LOCK_SLEEPER to indicate
+ * the nature of the wakeup.
+ */
+int wake_up_lock_sleeper(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_ALL, WF_LOCK_SLEEPER);
+}
+
 int wake_up_state(struct task_struct *p, unsigned int state)
 {
 	return try_to_wake_up(p, state, 0);
@@ -1967,8 +1973,12 @@ static void finish_task_switch(struct rq
 	finish_arch_post_lock_switch();
 
 	fire_sched_in_preempt_notifiers(current);
+	/*
+	 * We use mmdrop_delayed() here so we don't have to do the
+	 * full __mmdrop() when we are the last user.
+	 */
 	if (mm)
-		mmdrop(mm);
+		mmdrop_delayed(mm);
 	if (unlikely(prev_state == TASK_DEAD)) {
 		/*
 		 * Remove function-return probe instances associated with this
@@ -3134,6 +3144,126 @@ static inline void schedule_debug(struct
 	schedstat_inc(this_rq(), sched_count);
 }
 
+#if defined(CONFIG_PREEMPT_RT_FULL) && defined(CONFIG_SMP)
+#define MIGRATE_DISABLE_SET_AFFIN	(1<<30) /* Can't make a negative */
+#define migrate_disabled_updated(p)	((p)->migrate_disable & MIGRATE_DISABLE_SET_AFFIN)
+#define migrate_disable_count(p)	((p)->migrate_disable & ~MIGRATE_DISABLE_SET_AFFIN)
+
+static inline void update_migrate_disable(struct task_struct *p)
+{
+	const struct cpumask *mask;
+
+	if (likely(!p->migrate_disable))
+		return;
+
+	/* Did we already update affinity? */
+	if (unlikely(migrate_disabled_updated(p)))
+		return;
+
+	/*
+	 * Since this is always current we can get away with only locking
+	 * rq->lock, the ->cpus_allowed value can normally only be changed
+	 * while holding both p->pi_lock and rq->lock, but seeing that this
+	 * is current, we cannot actually be waking up, so all code that
+	 * relies on serialization against p->pi_lock is out of scope.
+	 *
+	 * Having rq->lock serializes us against things like
+	 * set_cpus_allowed_ptr() that can still happen concurrently.
+	 */
+	mask = tsk_cpus_allowed(p);
+
+	if (p->sched_class->set_cpus_allowed)
+		p->sched_class->set_cpus_allowed(p, mask);
+	p->rt.nr_cpus_allowed = cpumask_weight(mask);
+
+	/* Let migrate_enable know to fix things back up */
+	p->migrate_disable |= MIGRATE_DISABLE_SET_AFFIN;
+}
+
+void migrate_disable(void)
+{
+	struct task_struct *p = current;
+
+	if (in_atomic() || p->flags & PF_THREAD_BOUND) {
+#ifdef CONFIG_SCHED_DEBUG
+		p->migrate_disable_atomic++;
+#endif
+		return;
+	}
+
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(p->migrate_disable_atomic);
+#endif
+
+	preempt_disable();
+	if (p->migrate_disable) {
+		p->migrate_disable++;
+		preempt_enable();
+		return;
+	}
+
+	pin_current_cpu();
+	p->migrate_disable = 1;
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_disable);
+
+void migrate_enable(void)
+{
+	struct task_struct *p = current;
+	const struct cpumask *mask;
+	unsigned long flags;
+	struct rq *rq;
+
+	if (in_atomic() || p->flags & PF_THREAD_BOUND) {
+#ifdef CONFIG_SCHED_DEBUG
+		p->migrate_disable_atomic--;
+#endif
+		return;
+	}
+
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(p->migrate_disable_atomic);
+#endif
+	WARN_ON_ONCE(p->migrate_disable <= 0);
+
+	preempt_disable();
+	if (migrate_disable_count(p) > 1) {
+		p->migrate_disable--;
+		preempt_enable();
+		return;
+	}
+
+	if (unlikely(migrate_disabled_updated(p))) {
+		/*
+		 * Undo whatever update_migrate_disable() did, also see there
+		 * about locking.
+		 */
+		rq = this_rq();
+		raw_spin_lock_irqsave(&rq->lock, flags);
+
+		/*
+		 * Clearing migrate_disable causes tsk_cpus_allowed to
+		 * show the tasks original cpu affinity.
+		 */
+		p->migrate_disable = 0;
+		mask = tsk_cpus_allowed(p);
+		if (p->sched_class->set_cpus_allowed)
+			p->sched_class->set_cpus_allowed(p, mask);
+		p->rt.nr_cpus_allowed = cpumask_weight(mask);
+		raw_spin_unlock_irqrestore(&rq->lock, flags);
+	} else
+		p->migrate_disable = 0;
+
+	unpin_current_cpu();
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_enable);
+#else
+static inline void update_migrate_disable(struct task_struct *p) { }
+#define migrate_disabled_updated(p)		0
+#endif
+
 static void put_prev_task(struct rq *rq, struct task_struct *prev)
 {
 	if (prev->on_rq || rq->skip_clock_update < 0)
@@ -3193,6 +3323,8 @@ need_resched:
 
 	raw_spin_lock_irq(&rq->lock);
 
+	update_migrate_disable(prev);
+
 	switch_count = &prev->nivcsw;
 	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
 		if (unlikely(signal_pending_state(prev->state, prev))) {
@@ -3200,19 +3332,6 @@ need_resched:
 		} else {
 			deactivate_task(rq, prev, DEQUEUE_SLEEP);
 			prev->on_rq = 0;
-
-			/*
-			 * If a worker went to sleep, notify and ask workqueue
-			 * whether it wants to wake up a task to maintain
-			 * concurrency.
-			 */
-			if (prev->flags & PF_WQ_WORKER) {
-				struct task_struct *to_wakeup;
-
-				to_wakeup = wq_worker_sleeping(prev, cpu);
-				if (to_wakeup)
-					try_to_wake_up_local(to_wakeup);
-			}
 		}
 		switch_count = &prev->nvcsw;
 	}
@@ -3255,6 +3374,14 @@ static inline void sched_submit_work(str
 {
 	if (!tsk->state || tsk_is_pi_blocked(tsk))
 		return;
+
+	/*
+	 * If a worker went to sleep, notify and ask workqueue whether
+	 * it wants to wake up a task to maintain concurrency.
+	 */
+	if (tsk->flags & PF_WQ_WORKER)
+		wq_worker_sleeping(tsk);
+
 	/*
 	 * If we are going to sleep and we have plugged IO queued,
 	 * make sure to submit it to avoid deadlocks.
@@ -3263,12 +3390,19 @@ static inline void sched_submit_work(str
 		blk_schedule_flush_plug(tsk);
 }
 
+static inline void sched_update_worker(struct task_struct *tsk)
+{
+	if (tsk->flags & PF_WQ_WORKER)
+		wq_worker_running(tsk);
+}
+
 asmlinkage void __sched schedule(void)
 {
 	struct task_struct *tsk = current;
 
 	sched_submit_work(tsk);
 	__schedule();
+	sched_update_worker(tsk);
 }
 EXPORT_SYMBOL(schedule);
 
@@ -3348,7 +3482,16 @@ asmlinkage void __sched notrace preempt_
 
 	do {
 		add_preempt_count_notrace(PREEMPT_ACTIVE);
+		/*
+		 * The add/subtract must not be traced by the function
+		 * tracer. But we still want to account for the
+		 * preempt off latency tracer. Since the _notrace versions
+		 * of add/subtract skip the accounting for latency tracer
+		 * we must force it manually.
+		 */
+		start_critical_timings();
 		__schedule();
+		stop_critical_timings();
 		sub_preempt_count_notrace(PREEMPT_ACTIVE);
 
 		/*
@@ -4543,9 +4686,17 @@ static inline int should_resched(void)
 
 static void __cond_resched(void)
 {
-	add_preempt_count(PREEMPT_ACTIVE);
-	__schedule();
-	sub_preempt_count(PREEMPT_ACTIVE);
+	do {
+		add_preempt_count(PREEMPT_ACTIVE);
+		__schedule();
+		sub_preempt_count(PREEMPT_ACTIVE);
+		/*
+		 * Check again in case we missed a preemption
+		 * opportunity between schedule and now.
+		 */
+		barrier();
+
+	} while (need_resched());
 }
 
 int __sched _cond_resched(void)
@@ -4586,6 +4737,7 @@ int __cond_resched_lock(spinlock_t *lock
 }
 EXPORT_SYMBOL(__cond_resched_lock);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 int __sched __cond_resched_softirq(void)
 {
 	BUG_ON(!in_softirq());
@@ -4599,6 +4751,7 @@ int __sched __cond_resched_softirq(void)
 	return 0;
 }
 EXPORT_SYMBOL(__cond_resched_softirq);
+#endif
 
 /**
  * yield - yield the current processor to other threads.
@@ -4953,11 +5106,12 @@ void __cpuinit init_idle(struct task_str
 #ifdef CONFIG_SMP
 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
 {
-	if (p->sched_class && p->sched_class->set_cpus_allowed)
-		p->sched_class->set_cpus_allowed(p, new_mask);
-
+	if (!migrate_disabled_updated(p)) {
+		if (p->sched_class && p->sched_class->set_cpus_allowed)
+			p->sched_class->set_cpus_allowed(p, new_mask);
+		p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
+	}
 	cpumask_copy(&p->cpus_allowed, new_mask);
-	p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
 }
 
 /*
@@ -5008,7 +5162,7 @@ int set_cpus_allowed_ptr(struct task_str
 	do_set_cpus_allowed(p, new_mask);
 
 	/* Can the task run on the task's current CPU? If so, we're done */
-	if (cpumask_test_cpu(task_cpu(p), new_mask))
+	if (cpumask_test_cpu(task_cpu(p), new_mask) || __migrate_disabled(p))
 		goto out;
 
 	dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
@@ -5097,6 +5251,8 @@ static int migration_cpu_stop(void *data
 
 #ifdef CONFIG_HOTPLUG_CPU
 
+static DEFINE_PER_CPU(struct mm_struct *, idle_last_mm);
+
 /*
  * Ensures that the idle task is using init_mm right before its cpu goes
  * offline.
@@ -5109,7 +5265,12 @@ void idle_task_exit(void)
 
 	if (mm != &init_mm)
 		switch_mm(mm, &init_mm, current);
-	mmdrop(mm);
+
+	/*
+	 * Defer the cleanup to an alive cpu. On RT we can neither
+	 * call mmdrop() nor mmdrop_delayed() from here.
+	 */
+	per_cpu(idle_last_mm, smp_processor_id()) = mm;
 }
 
 /*
@@ -5430,6 +5591,12 @@ migration_call(struct notifier_block *nf
 		migrate_nr_uninterruptible(rq);
 		calc_global_load_remove(rq);
 		break;
+	case CPU_DEAD:
+		if (per_cpu(idle_last_mm, cpu)) {
+			mmdrop(per_cpu(idle_last_mm, cpu));
+			per_cpu(idle_last_mm, cpu) = NULL;
+		}
+		break;
 #endif
 	}
 
@@ -7068,7 +7235,8 @@ void __init sched_init(void)
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 static inline int preempt_count_equals(int preempt_offset)
 {
-	int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
+	int nested = (preempt_count() & ~PREEMPT_ACTIVE) +
+		sched_rcu_preempt_depth();
 
 	return (nested == preempt_offset);
 }
Index: linux-3.4/kernel/workqueue.c
===================================================================
--- linux-3.4.orig/kernel/workqueue.c
+++ linux-3.4/kernel/workqueue.c
@@ -41,6 +41,7 @@
 #include <linux/debug_locks.h>
 #include <linux/lockdep.h>
 #include <linux/idr.h>
+#include <linux/delay.h>
 
 #include "workqueue_sched.h"
 
@@ -57,20 +58,10 @@ enum {
 	WORKER_DIE		= 1 << 1,	/* die die die */
 	WORKER_IDLE		= 1 << 2,	/* is idle */
 	WORKER_PREP		= 1 << 3,	/* preparing to run works */
-	WORKER_ROGUE		= 1 << 4,	/* not bound to any cpu */
-	WORKER_REBIND		= 1 << 5,	/* mom is home, come back */
-	WORKER_CPU_INTENSIVE	= 1 << 6,	/* cpu intensive */
-	WORKER_UNBOUND		= 1 << 7,	/* worker is unbound */
-
-	WORKER_NOT_RUNNING	= WORKER_PREP | WORKER_ROGUE | WORKER_REBIND |
-				  WORKER_CPU_INTENSIVE | WORKER_UNBOUND,
-
-	/* gcwq->trustee_state */
-	TRUSTEE_START		= 0,		/* start */
-	TRUSTEE_IN_CHARGE	= 1,		/* trustee in charge of gcwq */
-	TRUSTEE_BUTCHER		= 2,		/* butcher workers */
-	TRUSTEE_RELEASE		= 3,		/* release workers */
-	TRUSTEE_DONE		= 4,		/* trustee is done */
+	WORKER_CPU_INTENSIVE	= 1 << 4,	/* cpu intensive */
+	WORKER_UNBOUND		= 1 << 5,	/* worker is unbound */
+
+	WORKER_NOT_RUNNING	= WORKER_PREP | WORKER_CPU_INTENSIVE | WORKER_UNBOUND,
 
 	BUSY_WORKER_HASH_ORDER	= 6,		/* 64 pointers */
 	BUSY_WORKER_HASH_SIZE	= 1 << BUSY_WORKER_HASH_ORDER,
@@ -84,7 +75,6 @@ enum {
 						   (min two ticks) */
 	MAYDAY_INTERVAL		= HZ / 10,	/* and then every 100ms */
 	CREATE_COOLDOWN		= HZ,		/* time to breath after fail */
-	TRUSTEE_COOLDOWN	= HZ / 10,	/* for trustee draining */
 
 	/*
 	 * Rescue workers are used only on emergencies and shared by
@@ -136,7 +126,7 @@ struct worker {
 	unsigned long		last_active;	/* L: last active timestamp */
 	unsigned int		flags;		/* X: flags */
 	int			id;		/* I: worker id */
-	struct work_struct	rebind_work;	/* L: rebind worker to cpu */
+	int			sleeping;	/* None */
 };
 
 /*
@@ -163,10 +153,8 @@ struct global_cwq {
 
 	struct ida		worker_ida;	/* L: for worker IDs */
 
-	struct task_struct	*trustee;	/* L: for gcwq shutdown */
-	unsigned int		trustee_state;	/* L: trustee state */
-	wait_queue_head_t	trustee_wait;	/* trustee wait */
 	struct worker		*first_idle;	/* L: first idle worker */
+	wait_queue_head_t	idle_wait;
 } ____cacheline_aligned_in_smp;
 
 /*
@@ -655,66 +643,58 @@ static void wake_up_worker(struct global
 }
 
 /**
- * wq_worker_waking_up - a worker is waking up
- * @task: task waking up
- * @cpu: CPU @task is waking up to
- *
- * This function is called during try_to_wake_up() when a worker is
- * being awoken.
+ * wq_worker_running - a worker is running again
+ * @task: task returning from sleep
  *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
+ * This function is called when a worker returns from schedule()
  */
-void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
+void wq_worker_running(struct task_struct *task)
 {
 	struct worker *worker = kthread_data(task);
 
+	if (!worker->sleeping)
+		return;
 	if (!(worker->flags & WORKER_NOT_RUNNING))
-		atomic_inc(get_gcwq_nr_running(cpu));
+		atomic_inc(get_gcwq_nr_running(smp_processor_id()));
+	worker->sleeping = 0;
 }
 
 /**
  * wq_worker_sleeping - a worker is going to sleep
  * @task: task going to sleep
- * @cpu: CPU in question, must be the current CPU number
- *
- * This function is called during schedule() when a busy worker is
- * going to sleep.  Worker on the same cpu can be woken up by
- * returning pointer to its task.
  *
- * CONTEXT:
- * spin_lock_irq(rq->lock)
- *
- * RETURNS:
- * Worker task on @cpu to wake up, %NULL if none.
+ * This function is called from schedule() when a busy worker is
+ * going to sleep.
  */
-struct task_struct *wq_worker_sleeping(struct task_struct *task,
-				       unsigned int cpu)
+void wq_worker_sleeping(struct task_struct *task)
 {
-	struct worker *worker = kthread_data(task), *to_wakeup = NULL;
-	struct global_cwq *gcwq = get_gcwq(cpu);
-	atomic_t *nr_running = get_gcwq_nr_running(cpu);
+	struct worker *worker = kthread_data(task);
+	struct global_cwq *gcwq;
+	int cpu;
 
 	if (worker->flags & WORKER_NOT_RUNNING)
-		return NULL;
+		return;
 
-	/* this can only happen on the local cpu */
-	BUG_ON(cpu != raw_smp_processor_id());
+	if (WARN_ON_ONCE(worker->sleeping))
+		return;
+
+	worker->sleeping = 1;
 
+	cpu = smp_processor_id();
+	gcwq = get_gcwq(cpu);
+	spin_lock_irq(&gcwq->lock);
 	/*
 	 * The counterpart of the following dec_and_test, implied mb,
 	 * worklist not empty test sequence is in insert_work().
 	 * Please read comment there.
-	 *
-	 * NOT_RUNNING is clear.  This means that trustee is not in
-	 * charge and we're running on the local cpu w/ rq lock held
-	 * and preemption disabled, which in turn means that none else
-	 * could be manipulating idle_list, so dereferencing idle_list
-	 * without gcwq lock is safe.
-	 */
-	if (atomic_dec_and_test(nr_running) && !list_empty(&gcwq->worklist))
-		to_wakeup = first_worker(gcwq);
-	return to_wakeup ? to_wakeup->task : NULL;
+	 */
+	if (atomic_dec_and_test(get_gcwq_nr_running(cpu)) &&
+	    !list_empty(&gcwq->worklist)) {
+		worker = first_worker(gcwq);
+		if (worker)
+			wake_up_process(worker->task);
+	}
+	spin_unlock_irq(&gcwq->lock);
 }
 
 /**
@@ -976,13 +956,38 @@ static bool is_chained_work(struct workq
 	return false;
 }
 
-static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
-			 struct work_struct *work)
+static void ___queue_work(struct workqueue_struct *wq, struct global_cwq *gcwq,
+			  struct work_struct *work)
 {
-	struct global_cwq *gcwq;
 	struct cpu_workqueue_struct *cwq;
 	struct list_head *worklist;
 	unsigned int work_flags;
+
+	/* gcwq determined, get cwq and queue */
+	cwq = get_cwq(gcwq->cpu, wq);
+	trace_workqueue_queue_work(gcwq->cpu, cwq, work);
+
+	BUG_ON(!list_empty(&work->entry));
+
+	cwq->nr_in_flight[cwq->work_color]++;
+	work_flags = work_color_to_flags(cwq->work_color);
+
+	if (likely(cwq->nr_active < cwq->max_active)) {
+		trace_workqueue_activate_work(work);
+		cwq->nr_active++;
+		worklist = gcwq_determine_ins_pos(gcwq, cwq);
+	} else {
+		work_flags |= WORK_STRUCT_DELAYED;
+		worklist = &cwq->delayed_works;
+	}
+
+	insert_work(cwq, work, worklist, work_flags);
+}
+
+static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
+			 struct work_struct *work)
+{
+	struct global_cwq *gcwq;
 	unsigned long flags;
 
 	debug_work_activate(work);
@@ -1028,27 +1033,32 @@ static void __queue_work(unsigned int cp
 		spin_lock_irqsave(&gcwq->lock, flags);
 	}
 
-	/* gcwq determined, get cwq and queue */
-	cwq = get_cwq(gcwq->cpu, wq);
-	trace_workqueue_queue_work(cpu, cwq, work);
+	___queue_work(wq, gcwq, work);
 
-	BUG_ON(!list_empty(&work->entry));
+	spin_unlock_irqrestore(&gcwq->lock, flags);
+}
 
-	cwq->nr_in_flight[cwq->work_color]++;
-	work_flags = work_color_to_flags(cwq->work_color);
+/**
+ * queue_work_on - queue work on specific cpu
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ *
+ * We queue the work to a specific CPU, the caller must ensure it
+ * can't go away.
+ */
+static int
+__queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
+{
+	int ret = 0;
 
-	if (likely(cwq->nr_active < cwq->max_active)) {
-		trace_workqueue_activate_work(work);
-		cwq->nr_active++;
-		worklist = gcwq_determine_ins_pos(gcwq, cwq);
-	} else {
-		work_flags |= WORK_STRUCT_DELAYED;
-		worklist = &cwq->delayed_works;
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		__queue_work(cpu, wq, work);
+		ret = 1;
 	}
-
-	insert_work(cwq, work, worklist, work_flags);
-
-	spin_unlock_irqrestore(&gcwq->lock, flags);
+	return ret;
 }
 
 /**
@@ -1065,34 +1075,19 @@ int queue_work(struct workqueue_struct *
 {
 	int ret;
 
-	ret = queue_work_on(get_cpu(), wq, work);
-	put_cpu();
+	ret = __queue_work_on(get_cpu_light(), wq, work);
+	put_cpu_light();
 
 	return ret;
 }
 EXPORT_SYMBOL_GPL(queue_work);
 
-/**
- * queue_work_on - queue work on specific cpu
- * @cpu: CPU number to execute work on
- * @wq: workqueue to use
- * @work: work to queue
- *
- * Returns 0 if @work was already on a queue, non-zero otherwise.
- *
- * We queue the work to a specific CPU, the caller must ensure it
- * can't go away.
- */
 int
 queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
 {
-	int ret = 0;
+	WARN_ON(wq->flags & WQ_NON_AFFINE);
 
-	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
-		__queue_work(cpu, wq, work);
-		ret = 1;
-	}
-	return ret;
+	return __queue_work_on(cpu, wq, work);
 }
 EXPORT_SYMBOL_GPL(queue_work_on);
 
@@ -1138,6 +1133,8 @@ int queue_delayed_work_on(int cpu, struc
 	struct timer_list *timer = &dwork->timer;
 	struct work_struct *work = &dwork->work;
 
+	WARN_ON((wq->flags & WQ_NON_AFFINE) && cpu != -1);
+
 	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
 		unsigned int lcpu;
 
@@ -1203,12 +1200,13 @@ static void worker_enter_idle(struct wor
 	/* idle_list is LIFO */
 	list_add(&worker->entry, &gcwq->idle_list);
 
-	if (likely(!(worker->flags & WORKER_ROGUE))) {
-		if (too_many_workers(gcwq) && !timer_pending(&gcwq->idle_timer))
-			mod_timer(&gcwq->idle_timer,
-				  jiffies + IDLE_WORKER_TIMEOUT);
-	} else
-		wake_up_all(&gcwq->trustee_wait);
+	if (gcwq->nr_idle == gcwq->nr_workers)
+		wake_up_all(&gcwq->idle_wait);
+
+	if (too_many_workers(gcwq) && !timer_pending(&gcwq->idle_timer)) {
+		mod_timer(&gcwq->idle_timer,
+				jiffies + IDLE_WORKER_TIMEOUT);
+	}
 
 	/* sanity check nr_running */
 	WARN_ON_ONCE(gcwq->nr_workers == gcwq->nr_idle &&
@@ -1285,8 +1283,14 @@ __acquires(&gcwq->lock)
 			return false;
 		if (task_cpu(task) == gcwq->cpu &&
 		    cpumask_equal(&current->cpus_allowed,
-				  get_cpu_mask(gcwq->cpu)))
+				  get_cpu_mask(gcwq->cpu))) {
+			/*
+			 * Since we're binding to a particular cpu and need to
+			 * stay there for correctness, mark us PF_THREAD_BOUND.
+			 */
+			task->flags |= PF_THREAD_BOUND;
 			return true;
+		}
 		spin_unlock_irq(&gcwq->lock);
 
 		/*
@@ -1300,20 +1304,15 @@ __acquires(&gcwq->lock)
 	}
 }
 
-/*
- * Function for worker->rebind_work used to rebind rogue busy workers
- * to the associated cpu which is coming back online.  This is
- * scheduled by cpu up but can race with other cpu hotplug operations
- * and may be executed twice without intervening cpu down.
- */
-static void worker_rebind_fn(struct work_struct *work)
+static void worker_unbind_and_unlock(struct worker *worker)
 {
-	struct worker *worker = container_of(work, struct worker, rebind_work);
 	struct global_cwq *gcwq = worker->gcwq;
+	struct task_struct *task = worker->task;
 
-	if (worker_maybe_bind_and_lock(worker))
-		worker_clr_flags(worker, WORKER_REBIND);
-
+	/*
+	 * Its no longer required we're PF_THREAD_BOUND, the work is done.
+	 */
+	task->flags &= ~PF_THREAD_BOUND;
 	spin_unlock_irq(&gcwq->lock);
 }
 
@@ -1325,7 +1324,6 @@ static struct worker *alloc_worker(void)
 	if (worker) {
 		INIT_LIST_HEAD(&worker->entry);
 		INIT_LIST_HEAD(&worker->scheduled);
-		INIT_WORK(&worker->rebind_work, worker_rebind_fn);
 		/* on creation a worker is in !idle && prep state */
 		worker->flags = WORKER_PREP;
 	}
@@ -1380,15 +1378,9 @@ static struct worker *create_worker(stru
 	if (IS_ERR(worker->task))
 		goto fail;
 
-	/*
-	 * A rogue worker will become a regular one if CPU comes
-	 * online later on.  Make sure every worker has
-	 * PF_THREAD_BOUND set.
-	 */
 	if (bind && !on_unbound_cpu)
 		kthread_bind(worker->task, gcwq->cpu);
 	else {
-		worker->task->flags |= PF_THREAD_BOUND;
 		if (on_unbound_cpu)
 			worker->flags |= WORKER_UNBOUND;
 	}
@@ -1665,13 +1657,6 @@ static bool manage_workers(struct worker
 
 	gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
 
-	/*
-	 * The trustee might be waiting to take over the manager
-	 * position, tell it we're done.
-	 */
-	if (unlikely(gcwq->trustee))
-		wake_up_all(&gcwq->trustee_wait);
-
 	return ret;
 }
 
@@ -2072,7 +2057,7 @@ repeat:
 		if (keep_working(gcwq))
 			wake_up_worker(gcwq);
 
-		spin_unlock_irq(&gcwq->lock);
+		worker_unbind_and_unlock(rescuer);
 	}
 
 	schedule();
@@ -3022,7 +3007,6 @@ struct workqueue_struct *__alloc_workque
 		if (IS_ERR(rescuer->task))
 			goto err;
 
-		rescuer->task->flags |= PF_THREAD_BOUND;
 		wake_up_process(rescuer->task);
 	}
 
@@ -3212,171 +3196,76 @@ EXPORT_SYMBOL_GPL(work_busy);
  * gcwqs serve mix of short, long and very long running works making
  * blocked draining impractical.
  *
- * This is solved by allowing a gcwq to be detached from CPU, running
- * it with unbound (rogue) workers and allowing it to be reattached
- * later if the cpu comes back online.  A separate thread is created
- * to govern a gcwq in such state and is called the trustee of the
- * gcwq.
- *
- * Trustee states and their descriptions.
- *
- * START	Command state used on startup.  On CPU_DOWN_PREPARE, a
- *		new trustee is started with this state.
- *
- * IN_CHARGE	Once started, trustee will enter this state after
- *		assuming the manager role and making all existing
- *		workers rogue.  DOWN_PREPARE waits for trustee to
- *		enter this state.  After reaching IN_CHARGE, trustee
- *		tries to execute the pending worklist until it's empty
- *		and the state is set to BUTCHER, or the state is set
- *		to RELEASE.
- *
- * BUTCHER	Command state which is set by the cpu callback after
- *		the cpu has went down.  Once this state is set trustee
- *		knows that there will be no new works on the worklist
- *		and once the worklist is empty it can proceed to
- *		killing idle workers.
- *
- * RELEASE	Command state which is set by the cpu callback if the
- *		cpu down has been canceled or it has come online
- *		again.  After recognizing this state, trustee stops
- *		trying to drain or butcher and clears ROGUE, rebinds
- *		all remaining workers back to the cpu and releases
- *		manager role.
- *
- * DONE		Trustee will enter this state after BUTCHER or RELEASE
- *		is complete.
- *
- *          trustee                 CPU                draining
- *         took over                down               complete
- * START -----------> IN_CHARGE -----------> BUTCHER -----------> DONE
- *                        |                     |                  ^
- *                        | CPU is back online  v   return workers |
- *                         ----------------> RELEASE --------------
  */
 
-/**
- * trustee_wait_event_timeout - timed event wait for trustee
- * @cond: condition to wait for
- * @timeout: timeout in jiffies
- *
- * wait_event_timeout() for trustee to use.  Handles locking and
- * checks for RELEASE request.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
- * multiple times.  To be used by trustee.
- *
- * RETURNS:
- * Positive indicating left time if @cond is satisfied, 0 if timed
- * out, -1 if canceled.
- */
-#define trustee_wait_event_timeout(cond, timeout) ({			\
-	long __ret = (timeout);						\
-	while (!((cond) || (gcwq->trustee_state == TRUSTEE_RELEASE)) &&	\
-	       __ret) {							\
-		spin_unlock_irq(&gcwq->lock);				\
-		__wait_event_timeout(gcwq->trustee_wait, (cond) ||	\
-			(gcwq->trustee_state == TRUSTEE_RELEASE),	\
-			__ret);						\
-		spin_lock_irq(&gcwq->lock);				\
-	}								\
-	gcwq->trustee_state == TRUSTEE_RELEASE ? -1 : (__ret);		\
-})
+static int __devinit workqueue_cpu_up_callback(struct notifier_block *nfb,
+						unsigned long action,
+						void *hcpu)
+{
+	unsigned int cpu = (unsigned long)hcpu;
+	struct global_cwq *gcwq = get_gcwq(cpu);
+	struct worker *uninitialized_var(new_worker);
+	unsigned long flags;
 
-/**
- * trustee_wait_event - event wait for trustee
- * @cond: condition to wait for
- *
- * wait_event() for trustee to use.  Automatically handles locking and
- * checks for CANCEL request.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
- * multiple times.  To be used by trustee.
- *
- * RETURNS:
- * 0 if @cond is satisfied, -1 if canceled.
- */
-#define trustee_wait_event(cond) ({					\
-	long __ret1;							\
-	__ret1 = trustee_wait_event_timeout(cond, MAX_SCHEDULE_TIMEOUT);\
-	__ret1 < 0 ? -1 : 0;						\
-})
+	action &= ~CPU_TASKS_FROZEN;
 
-static int __cpuinit trustee_thread(void *__gcwq)
-{
-	struct global_cwq *gcwq = __gcwq;
-	struct worker *worker;
-	struct work_struct *work;
-	struct hlist_node *pos;
-	long rc;
-	int i;
+	switch (action) {
+	case CPU_UP_PREPARE:
+		BUG_ON(gcwq->first_idle);
+		new_worker = create_worker(gcwq, false);
+		if (!new_worker)
+			return NOTIFY_BAD;
+	case CPU_UP_CANCELED:
+	case CPU_ONLINE:
+		break;
+	default:
+		return notifier_from_errno(0);
+	}
 
-	BUG_ON(gcwq->cpu != smp_processor_id());
+	/* some are called w/ irq disabled, don't disturb irq status */
+	spin_lock_irqsave(&gcwq->lock, flags);
 
-	spin_lock_irq(&gcwq->lock);
-	/*
-	 * Claim the manager position and make all workers rogue.
-	 * Trustee must be bound to the target cpu and can't be
-	 * cancelled.
-	 */
-	BUG_ON(gcwq->cpu != smp_processor_id());
-	rc = trustee_wait_event(!(gcwq->flags & GCWQ_MANAGING_WORKERS));
-	BUG_ON(rc < 0);
+	switch (action) {
+	case CPU_UP_PREPARE:
+		BUG_ON(gcwq->first_idle);
+		gcwq->first_idle = new_worker;
+		break;
 
-	gcwq->flags |= GCWQ_MANAGING_WORKERS;
+	case CPU_UP_CANCELED:
+		destroy_worker(gcwq->first_idle);
+		gcwq->first_idle = NULL;
+		break;
 
-	list_for_each_entry(worker, &gcwq->idle_list, entry)
-		worker->flags |= WORKER_ROGUE;
+	case CPU_ONLINE:
+		spin_unlock_irq(&gcwq->lock);
+		kthread_bind(gcwq->first_idle->task, cpu);
+		spin_lock_irq(&gcwq->lock);
+		gcwq->flags |= GCWQ_MANAGE_WORKERS;
+		start_worker(gcwq->first_idle);
+		gcwq->first_idle = NULL;
+		break;
+	}
 
-	for_each_busy_worker(worker, i, pos, gcwq)
-		worker->flags |= WORKER_ROGUE;
+	spin_unlock_irqrestore(&gcwq->lock, flags);
 
-	/*
-	 * Call schedule() so that we cross rq->lock and thus can
-	 * guarantee sched callbacks see the rogue flag.  This is
-	 * necessary as scheduler callbacks may be invoked from other
-	 * cpus.
-	 */
-	spin_unlock_irq(&gcwq->lock);
-	schedule();
-	spin_lock_irq(&gcwq->lock);
+	return notifier_from_errno(0);
+}
 
-	/*
-	 * Sched callbacks are disabled now.  Zap nr_running.  After
-	 * this, nr_running stays zero and need_more_worker() and
-	 * keep_working() are always true as long as the worklist is
-	 * not empty.
-	 */
-	atomic_set(get_gcwq_nr_running(gcwq->cpu), 0);
+static void flush_gcwq(struct global_cwq *gcwq)
+{
+	struct work_struct *work, *nw;
+	struct worker *worker, *n;
+	LIST_HEAD(non_affine_works);
 
-	spin_unlock_irq(&gcwq->lock);
-	del_timer_sync(&gcwq->idle_timer);
 	spin_lock_irq(&gcwq->lock);
+	list_for_each_entry_safe(work, nw, &gcwq->worklist, entry) {
+		struct workqueue_struct *wq = get_work_cwq(work)->wq;
 
-	/*
-	 * We're now in charge.  Notify and proceed to drain.  We need
-	 * to keep the gcwq running during the whole CPU down
-	 * procedure as other cpu hotunplug callbacks may need to
-	 * flush currently running tasks.
-	 */
-	gcwq->trustee_state = TRUSTEE_IN_CHARGE;
-	wake_up_all(&gcwq->trustee_wait);
-
-	/*
-	 * The original cpu is in the process of dying and may go away
-	 * anytime now.  When that happens, we and all workers would
-	 * be migrated to other cpus.  Try draining any left work.  We
-	 * want to get it over with ASAP - spam rescuers, wake up as
-	 * many idlers as necessary and create new ones till the
-	 * worklist is empty.  Note that if the gcwq is frozen, there
-	 * may be frozen works in freezable cwqs.  Don't declare
-	 * completion while frozen.
-	 */
-	while (gcwq->nr_workers != gcwq->nr_idle ||
-	       gcwq->flags & GCWQ_FREEZING ||
-	       gcwq->trustee_state == TRUSTEE_IN_CHARGE) {
+		if (wq->flags & WQ_NON_AFFINE)
+			list_move(&work->entry, &non_affine_works);
+	}
+
+	while (!list_empty(&gcwq->worklist)) {
 		int nr_works = 0;
 
 		list_for_each_entry(work, &gcwq->worklist, entry) {
@@ -3390,189 +3279,54 @@ static int __cpuinit trustee_thread(void
 			wake_up_process(worker->task);
 		}
 
+		spin_unlock_irq(&gcwq->lock);
+
 		if (need_to_create_worker(gcwq)) {
-			spin_unlock_irq(&gcwq->lock);
-			worker = create_worker(gcwq, false);
-			spin_lock_irq(&gcwq->lock);
-			if (worker) {
-				worker->flags |= WORKER_ROGUE;
+			worker = create_worker(gcwq, true);
+			if (worker)
 				start_worker(worker);
-			}
 		}
 
-		/* give a breather */
-		if (trustee_wait_event_timeout(false, TRUSTEE_COOLDOWN) < 0)
-			break;
-	}
-
-	/*
-	 * Either all works have been scheduled and cpu is down, or
-	 * cpu down has already been canceled.  Wait for and butcher
-	 * all workers till we're canceled.
-	 */
-	do {
-		rc = trustee_wait_event(!list_empty(&gcwq->idle_list));
-		while (!list_empty(&gcwq->idle_list))
-			destroy_worker(list_first_entry(&gcwq->idle_list,
-							struct worker, entry));
-	} while (gcwq->nr_workers && rc >= 0);
-
-	/*
-	 * At this point, either draining has completed and no worker
-	 * is left, or cpu down has been canceled or the cpu is being
-	 * brought back up.  There shouldn't be any idle one left.
-	 * Tell the remaining busy ones to rebind once it finishes the
-	 * currently scheduled works by scheduling the rebind_work.
-	 */
-	WARN_ON(!list_empty(&gcwq->idle_list));
-
-	for_each_busy_worker(worker, i, pos, gcwq) {
-		struct work_struct *rebind_work = &worker->rebind_work;
+		wait_event_timeout(gcwq->idle_wait,
+				gcwq->nr_idle == gcwq->nr_workers, HZ/10);
 
-		/*
-		 * Rebind_work may race with future cpu hotplug
-		 * operations.  Use a separate flag to mark that
-		 * rebinding is scheduled.
-		 */
-		worker->flags |= WORKER_REBIND;
-		worker->flags &= ~WORKER_ROGUE;
+		spin_lock_irq(&gcwq->lock);
+	}
 
-		/* queue rebind_work, wq doesn't matter, use the default one */
-		if (test_and_set_bit(WORK_STRUCT_PENDING_BIT,
-				     work_data_bits(rebind_work)))
-			continue;
+	WARN_ON(gcwq->nr_workers != gcwq->nr_idle);
 
-		debug_work_activate(rebind_work);
-		insert_work(get_cwq(gcwq->cpu, system_wq), rebind_work,
-			    worker->scheduled.next,
-			    work_color_to_flags(WORK_NO_COLOR));
-	}
+	list_for_each_entry_safe(worker, n, &gcwq->idle_list, entry)
+		destroy_worker(worker);
 
-	/* relinquish manager role */
-	gcwq->flags &= ~GCWQ_MANAGING_WORKERS;
+	WARN_ON(gcwq->nr_workers || gcwq->nr_idle);
 
-	/* notify completion */
-	gcwq->trustee = NULL;
-	gcwq->trustee_state = TRUSTEE_DONE;
-	wake_up_all(&gcwq->trustee_wait);
 	spin_unlock_irq(&gcwq->lock);
-	return 0;
-}
 
-/**
- * wait_trustee_state - wait for trustee to enter the specified state
- * @gcwq: gcwq the trustee of interest belongs to
- * @state: target state to wait for
- *
- * Wait for the trustee to reach @state.  DONE is already matched.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
- * multiple times.  To be used by cpu_callback.
- */
-static void __cpuinit wait_trustee_state(struct global_cwq *gcwq, int state)
-__releases(&gcwq->lock)
-__acquires(&gcwq->lock)
-{
-	if (!(gcwq->trustee_state == state ||
-	      gcwq->trustee_state == TRUSTEE_DONE)) {
-		spin_unlock_irq(&gcwq->lock);
-		__wait_event(gcwq->trustee_wait,
-			     gcwq->trustee_state == state ||
-			     gcwq->trustee_state == TRUSTEE_DONE);
-		spin_lock_irq(&gcwq->lock);
+	gcwq = get_gcwq(get_cpu_light());
+	spin_lock_irq(&gcwq->lock);
+	list_for_each_entry_safe(work, nw, &non_affine_works, entry) {
+		list_del_init(&work->entry);
+		___queue_work(get_work_cwq(work)->wq, gcwq, work);
 	}
+	spin_unlock_irq(&gcwq->lock);
+	put_cpu_light();
 }
 
-static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
+static int __devinit workqueue_cpu_down_callback(struct notifier_block *nfb,
 						unsigned long action,
 						void *hcpu)
 {
 	unsigned int cpu = (unsigned long)hcpu;
 	struct global_cwq *gcwq = get_gcwq(cpu);
-	struct task_struct *new_trustee = NULL;
-	struct worker *uninitialized_var(new_worker);
-	unsigned long flags;
 
 	action &= ~CPU_TASKS_FROZEN;
 
-	switch (action) {
-	case CPU_DOWN_PREPARE:
-		new_trustee = kthread_create(trustee_thread, gcwq,
-					     "workqueue_trustee/%d\n", cpu);
-		if (IS_ERR(new_trustee))
-			return notifier_from_errno(PTR_ERR(new_trustee));
-		kthread_bind(new_trustee, cpu);
-		/* fall through */
-	case CPU_UP_PREPARE:
-		BUG_ON(gcwq->first_idle);
-		new_worker = create_worker(gcwq, false);
-		if (!new_worker) {
-			if (new_trustee)
-				kthread_stop(new_trustee);
-			return NOTIFY_BAD;
-		}
-	}
+        switch (action) {
+        case CPU_DOWN_PREPARE:
+                flush_gcwq(gcwq);
+                break;
+        }
 
-	/* some are called w/ irq disabled, don't disturb irq status */
-	spin_lock_irqsave(&gcwq->lock, flags);
-
-	switch (action) {
-	case CPU_DOWN_PREPARE:
-		/* initialize trustee and tell it to acquire the gcwq */
-		BUG_ON(gcwq->trustee || gcwq->trustee_state != TRUSTEE_DONE);
-		gcwq->trustee = new_trustee;
-		gcwq->trustee_state = TRUSTEE_START;
-		wake_up_process(gcwq->trustee);
-		wait_trustee_state(gcwq, TRUSTEE_IN_CHARGE);
-		/* fall through */
-	case CPU_UP_PREPARE:
-		BUG_ON(gcwq->first_idle);
-		gcwq->first_idle = new_worker;
-		break;
-
-	case CPU_DYING:
-		/*
-		 * Before this, the trustee and all workers except for
-		 * the ones which are still executing works from
-		 * before the last CPU down must be on the cpu.  After
-		 * this, they'll all be diasporas.
-		 */
-		gcwq->flags |= GCWQ_DISASSOCIATED;
-		break;
-
-	case CPU_POST_DEAD:
-		gcwq->trustee_state = TRUSTEE_BUTCHER;
-		/* fall through */
-	case CPU_UP_CANCELED:
-		destroy_worker(gcwq->first_idle);
-		gcwq->first_idle = NULL;
-		break;
-
-	case CPU_DOWN_FAILED:
-	case CPU_ONLINE:
-		gcwq->flags &= ~GCWQ_DISASSOCIATED;
-		if (gcwq->trustee_state != TRUSTEE_DONE) {
-			gcwq->trustee_state = TRUSTEE_RELEASE;
-			wake_up_process(gcwq->trustee);
-			wait_trustee_state(gcwq, TRUSTEE_DONE);
-		}
-
-		/*
-		 * Trustee is done and there might be no worker left.
-		 * Put the first_idle in and request a real manager to
-		 * take a look.
-		 */
-		spin_unlock_irq(&gcwq->lock);
-		kthread_bind(gcwq->first_idle->task, cpu);
-		spin_lock_irq(&gcwq->lock);
-		gcwq->flags |= GCWQ_MANAGE_WORKERS;
-		start_worker(gcwq->first_idle);
-		gcwq->first_idle = NULL;
-		break;
-	}
-
-	spin_unlock_irqrestore(&gcwq->lock, flags);
 
 	return notifier_from_errno(0);
 }
@@ -3770,7 +3524,8 @@ static int __init init_workqueues(void)
 	unsigned int cpu;
 	int i;
 
-	cpu_notifier(workqueue_cpu_callback, CPU_PRI_WORKQUEUE);
+	cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_ACTIVE);
+ 	hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_INACTIVE);
 
 	/* initialize gcwqs */
 	for_each_gcwq_cpu(cpu) {
@@ -3793,9 +3548,7 @@ static int __init init_workqueues(void)
 			    (unsigned long)gcwq);
 
 		ida_init(&gcwq->worker_ida);
-
-		gcwq->trustee_state = TRUSTEE_DONE;
-		init_waitqueue_head(&gcwq->trustee_wait);
+		init_waitqueue_head(&gcwq->idle_wait);
 	}
 
 	/* create the initial worker */
Index: linux-3.4/kernel/workqueue_sched.h
===================================================================
--- linux-3.4.orig/kernel/workqueue_sched.h
+++ linux-3.4/kernel/workqueue_sched.h
@@ -4,6 +4,5 @@
  * Scheduler hooks for concurrency managed workqueue.  Only to be
  * included from sched.c and workqueue.c.
  */
-void wq_worker_waking_up(struct task_struct *task, unsigned int cpu);
-struct task_struct *wq_worker_sleeping(struct task_struct *task,
-				       unsigned int cpu);
+void wq_worker_running(struct task_struct *task);
+void wq_worker_sleeping(struct task_struct *task);
Index: linux-3.4/arch/mips/kernel/signal.c
===================================================================
--- linux-3.4.orig/arch/mips/kernel/signal.c
+++ linux-3.4/arch/mips/kernel/signal.c
@@ -605,6 +605,9 @@ static void do_signal(struct pt_regs *re
 	if (!user_mode(regs))
 		return;
 
+	local_irq_enable();
+	preempt_check_resched();
+
 	if (test_thread_flag(TIF_RESTORE_SIGMASK))
 		oldset = &current->saved_sigmask;
 	else
Index: linux-3.4/arch/arm/kernel/signal.c
===================================================================
--- linux-3.4.orig/arch/arm/kernel/signal.c
+++ linux-3.4/arch/arm/kernel/signal.c
@@ -664,6 +664,9 @@ static void do_signal(struct pt_regs *re
 	if (!user_mode(regs))
 		return;
 
+	local_irq_enable();
+	preempt_check_resched();
+
 	/*
 	 * If we were from a system call, check for system call restarting...
 	 */
Index: linux-3.4/include/linux/seqlock.h
===================================================================
--- linux-3.4.orig/include/linux/seqlock.h
+++ linux-3.4/include/linux/seqlock.h
@@ -30,92 +30,12 @@
 #include <linux/preempt.h>
 #include <asm/processor.h>
 
-typedef struct {
-	unsigned sequence;
-	spinlock_t lock;
-} seqlock_t;
-
-/*
- * These macros triggered gcc-3.x compile-time problems.  We think these are
- * OK now.  Be cautious.
- */
-#define __SEQLOCK_UNLOCKED(lockname) \
-		 { 0, __SPIN_LOCK_UNLOCKED(lockname) }
-
-#define seqlock_init(x)					\
-	do {						\
-		(x)->sequence = 0;			\
-		spin_lock_init(&(x)->lock);		\
-	} while (0)
-
-#define DEFINE_SEQLOCK(x) \
-		seqlock_t x = __SEQLOCK_UNLOCKED(x)
-
-/* Lock out other writers and update the count.
- * Acts like a normal spin_lock/unlock.
- * Don't need preempt_disable() because that is in the spin_lock already.
- */
-static inline void write_seqlock(seqlock_t *sl)
-{
-	spin_lock(&sl->lock);
-	++sl->sequence;
-	smp_wmb();
-}
-
-static inline void write_sequnlock(seqlock_t *sl)
-{
-	smp_wmb();
-	sl->sequence++;
-	spin_unlock(&sl->lock);
-}
-
-static inline int write_tryseqlock(seqlock_t *sl)
-{
-	int ret = spin_trylock(&sl->lock);
-
-	if (ret) {
-		++sl->sequence;
-		smp_wmb();
-	}
-	return ret;
-}
-
-/* Start of read calculation -- fetch last complete writer token */
-static __always_inline unsigned read_seqbegin(const seqlock_t *sl)
-{
-	unsigned ret;
-
-repeat:
-	ret = ACCESS_ONCE(sl->sequence);
-	if (unlikely(ret & 1)) {
-		cpu_relax();
-		goto repeat;
-	}
-	smp_rmb();
-
-	return ret;
-}
-
-/*
- * Test if reader processed invalid data.
- *
- * If sequence value changed then writer changed data while in section.
- */
-static __always_inline int read_seqretry(const seqlock_t *sl, unsigned start)
-{
-	smp_rmb();
-
-	return unlikely(sl->sequence != start);
-}
-
-
 /*
  * Version using sequence counter only.
  * This can be used when code has its own mutex protecting the
  * updating starting before the write_seqcountbeqin() and ending
  * after the write_seqcount_end().
  */
-
 typedef struct seqcount {
 	unsigned sequence;
 } seqcount_t;
@@ -197,7 +117,6 @@ static inline int __read_seqcount_retry(
 static inline int read_seqcount_retry(const seqcount_t *s, unsigned start)
 {
 	smp_rmb();
-
 	return __read_seqcount_retry(s, start);
 }
 
@@ -206,18 +125,30 @@ static inline int read_seqcount_retry(co
  * Sequence counter only version assumes that callers are using their
  * own mutexing.
  */
-static inline void write_seqcount_begin(seqcount_t *s)
+static inline void __write_seqcount_begin(seqcount_t *s)
 {
 	s->sequence++;
 	smp_wmb();
 }
 
-static inline void write_seqcount_end(seqcount_t *s)
+static inline void write_seqcount_begin(seqcount_t *s)
+{
+	preempt_disable_rt();
+	__write_seqcount_begin(s);
+}
+
+static inline void __write_seqcount_end(seqcount_t *s)
 {
 	smp_wmb();
 	s->sequence++;
 }
 
+static inline void write_seqcount_end(seqcount_t *s)
+{
+	__write_seqcount_end(s);
+	preempt_enable_rt();
+}
+
 /**
  * write_seqcount_barrier - invalidate in-progress read-side seq operations
  * @s: pointer to seqcount_t
@@ -231,31 +162,124 @@ static inline void write_seqcount_barrie
 	s->sequence+=2;
 }
 
+typedef struct {
+	struct seqcount seqcount;
+	spinlock_t lock;
+} seqlock_t;
+
+/*
+ * These macros triggered gcc-3.x compile-time problems.  We think these are
+ * OK now.  Be cautious.
+ */
+#define __SEQLOCK_UNLOCKED(lockname)			\
+	{						\
+		.seqcount = SEQCNT_ZERO,		\
+		.lock =	__SPIN_LOCK_UNLOCKED(lockname)	\
+	}
+
+#define seqlock_init(x)					\
+	do {						\
+		seqcount_init(&(x)->seqcount);		\
+		spin_lock_init(&(x)->lock);		\
+	} while (0)
+
+#define DEFINE_SEQLOCK(x) \
+		seqlock_t x = __SEQLOCK_UNLOCKED(x)
+
+/*
+ * Read side functions for starting and finalizing a read side section.
+ */
+#ifndef CONFIG_PREEMPT_RT_FULL
+static inline unsigned read_seqbegin(const seqlock_t *sl)
+{
+	return read_seqcount_begin(&sl->seqcount);
+}
+#else
+/*
+ * Starvation safe read side for RT
+ */
+static inline unsigned read_seqbegin(seqlock_t *sl)
+{
+	unsigned ret;
+
+repeat:
+	ret = sl->seqcount.sequence;
+	if (unlikely(ret & 1)) {
+		/*
+		 * Take the lock and let the writer proceed (i.e. evtl
+		 * boost it), otherwise we could loop here forever.
+		 */
+		spin_lock(&sl->lock);
+		spin_unlock(&sl->lock);
+		goto repeat;
+	}
+	return ret;
+}
+#endif
+
+static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start)
+{
+	return read_seqcount_retry(&sl->seqcount, start);
+}
+
 /*
- * Possible sw/hw IRQ protected versions of the interfaces.
+ * Lock out other writers and update the count.
+ * Acts like a normal spin_lock/unlock.
+ * Don't need preempt_disable() because that is in the spin_lock already.
  */
+static inline void write_seqlock(seqlock_t *sl)
+{
+	spin_lock(&sl->lock);
+	__write_seqcount_begin(&sl->seqcount);
+}
+
+static inline void write_sequnlock(seqlock_t *sl)
+{
+	__write_seqcount_end(&sl->seqcount);
+	spin_unlock(&sl->lock);
+}
+
+static inline void write_seqlock_bh(seqlock_t *sl)
+{
+	spin_lock_bh(&sl->lock);
+	__write_seqcount_begin(&sl->seqcount);
+}
+
+static inline void write_sequnlock_bh(seqlock_t *sl)
+{
+	__write_seqcount_end(&sl->seqcount);
+	spin_unlock_bh(&sl->lock);
+}
+
+static inline void write_seqlock_irq(seqlock_t *sl)
+{
+	spin_lock_irq(&sl->lock);
+	__write_seqcount_begin(&sl->seqcount);
+}
+
+static inline void write_sequnlock_irq(seqlock_t *sl)
+{
+	__write_seqcount_end(&sl->seqcount);
+	spin_unlock_irq(&sl->lock);
+}
+
+static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&sl->lock, flags);
+	__write_seqcount_begin(&sl->seqcount);
+	return flags;
+}
+
 #define write_seqlock_irqsave(lock, flags)				\
-	do { local_irq_save(flags); write_seqlock(lock); } while (0)
-#define write_seqlock_irq(lock)						\
-	do { local_irq_disable();   write_seqlock(lock); } while (0)
-#define write_seqlock_bh(lock)						\
-        do { local_bh_disable();    write_seqlock(lock); } while (0)
-
-#define write_sequnlock_irqrestore(lock, flags)				\
-	do { write_sequnlock(lock); local_irq_restore(flags); } while(0)
-#define write_sequnlock_irq(lock)					\
-	do { write_sequnlock(lock); local_irq_enable(); } while(0)
-#define write_sequnlock_bh(lock)					\
-	do { write_sequnlock(lock); local_bh_enable(); } while(0)
-
-#define read_seqbegin_irqsave(lock, flags)				\
-	({ local_irq_save(flags);   read_seqbegin(lock); })
-
-#define read_seqretry_irqrestore(lock, iv, flags)			\
-	({								\
-		int ret = read_seqretry(lock, iv);			\
-		local_irq_restore(flags);				\
-		ret;							\
-	})
+	do { flags = __write_seqlock_irqsave(lock); } while (0)
+
+static inline void
+write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags)
+{
+	__write_seqcount_end(&sl->seqcount);
+	spin_unlock_irqrestore(&sl->lock, flags);
+}
 
 #endif /* __LINUX_SEQLOCK_H */
Index: linux-3.4/kernel/time/jiffies.c
===================================================================
--- linux-3.4.orig/kernel/time/jiffies.c
+++ linux-3.4/kernel/time/jiffies.c
@@ -74,9 +74,9 @@ u64 get_jiffies_64(void)
 	u64 ret;
 
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqcount_begin(&xtime_seq);
 		ret = jiffies_64;
-	} while (read_seqretry(&xtime_lock, seq));
+	} while (read_seqcount_retry(&xtime_seq, seq));
 	return ret;
 }
 EXPORT_SYMBOL(get_jiffies_64);
Index: linux-3.4/kernel/time/tick-common.c
===================================================================
--- linux-3.4.orig/kernel/time/tick-common.c
+++ linux-3.4/kernel/time/tick-common.c
@@ -63,13 +63,15 @@ int tick_is_oneshot_available(void)
 static void tick_periodic(int cpu)
 {
 	if (tick_do_timer_cpu == cpu) {
-		write_seqlock(&xtime_lock);
+		raw_spin_lock(&xtime_lock);
+		write_seqcount_begin(&xtime_seq);
 
 		/* Keep track of the next tick event */
 		tick_next_period = ktime_add(tick_next_period, tick_period);
 
 		do_timer(1);
-		write_sequnlock(&xtime_lock);
+		write_seqcount_end(&xtime_seq);
+		raw_spin_unlock(&xtime_lock);
 	}
 
 	update_process_times(user_mode(get_irq_regs()));
@@ -130,9 +132,9 @@ void tick_setup_periodic(struct clock_ev
 		ktime_t next;
 
 		do {
-			seq = read_seqbegin(&xtime_lock);
+			seq = read_seqcount_begin(&xtime_seq);
 			next = tick_next_period;
-		} while (read_seqretry(&xtime_lock, seq));
+		} while (read_seqcount_retry(&xtime_seq, seq));
 
 		clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
 
Index: linux-3.4/kernel/time/tick-internal.h
===================================================================
--- linux-3.4.orig/kernel/time/tick-internal.h
+++ linux-3.4/kernel/time/tick-internal.h
@@ -141,4 +141,5 @@ static inline int tick_device_is_functio
 #endif
 
 extern void do_timer(unsigned long ticks);
-extern seqlock_t xtime_lock;
+extern raw_spinlock_t xtime_lock;
+extern seqcount_t xtime_seq;
Index: linux-3.4/kernel/time/tick-sched.c
===================================================================
--- linux-3.4.orig/kernel/time/tick-sched.c
+++ linux-3.4/kernel/time/tick-sched.c
@@ -56,7 +56,8 @@ static void tick_do_update_jiffies64(kti
 		return;
 
 	/* Reevalute with xtime_lock held */
-	write_seqlock(&xtime_lock);
+	raw_spin_lock(&xtime_lock);
+	write_seqcount_begin(&xtime_seq);
 
 	delta = ktime_sub(now, last_jiffies_update);
 	if (delta.tv64 >= tick_period.tv64) {
@@ -79,7 +80,8 @@ static void tick_do_update_jiffies64(kti
 		/* Keep the tick_next_period variable up to date */
 		tick_next_period = ktime_add(last_jiffies_update, tick_period);
 	}
-	write_sequnlock(&xtime_lock);
+	write_seqcount_end(&xtime_seq);
+	raw_spin_unlock(&xtime_lock);
 }
 
 /*
@@ -89,12 +91,14 @@ static ktime_t tick_init_jiffy_update(vo
 {
 	ktime_t period;
 
-	write_seqlock(&xtime_lock);
+	raw_spin_lock(&xtime_lock);
+	write_seqcount_begin(&xtime_seq);
 	/* Did we start the jiffies update yet ? */
 	if (last_jiffies_update.tv64 == 0)
 		last_jiffies_update = tick_next_period;
 	period = last_jiffies_update;
-	write_sequnlock(&xtime_lock);
+	write_seqcount_end(&xtime_seq);
+	raw_spin_unlock(&xtime_lock);
 	return period;
 }
 
@@ -303,24 +307,18 @@ static void tick_nohz_stop_sched_tick(st
 		return;
 
 	if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
-		static int ratelimit;
-
-		if (ratelimit < 10) {
-			printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
-			       (unsigned int) local_softirq_pending());
-			ratelimit++;
-		}
+		softirq_check_pending_idle();
 		return;
 	}
 
 	ts->idle_calls++;
 	/* Read jiffies and the time when jiffies were updated last */
 	do {
-		seq = read_seqbegin(&xtime_lock);
+		seq = read_seqcount_begin(&xtime_seq);
 		last_update = last_jiffies_update;
 		last_jiffies = jiffies;
 		time_delta = timekeeping_max_deferment();
-	} while (read_seqretry(&xtime_lock, seq));
+	} while (read_seqcount_retry(&xtime_seq, seq));
 
 	if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
 	    arch_needs_cpu(cpu)) {
@@ -826,6 +824,7 @@ void tick_setup_sched_timer(void)
 	 * Emulate tick processing via per-CPU hrtimers:
 	 */
 	hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	ts->sched_timer.irqsafe = 1;
 	ts->sched_timer.function = tick_sched_timer;
 
 	/* Get the next period (per cpu) */
Index: linux-3.4/kernel/time/timekeeping.c
===================================================================
--- linux-3.4.orig/kernel/time/timekeeping.c
+++ linux-3.4/kernel/time/timekeeping.c
@@ -70,8 +70,9 @@ struct timekeeper {
 	/* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */
 	struct timespec raw_time;
 
-	/* Seqlock for all timekeeper values */
-	seqlock_t lock;
+	/* Open coded seqlock for all timekeeper values */
+	seqcount_t seq;
+	raw_spinlock_t lock;
 };
 
 static struct timekeeper timekeeper;
@@ -80,7 +81,8 @@ static struct timekeeper timekeeper;
  * This read-write spinlock protects us from races in SMP while
  * playing with xtime.
  */
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
+__cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(xtime_lock);
+seqcount_t xtime_seq;
 
 
 /* flag for if timekeeping is suspended */
@@ -228,7 +230,7 @@ void getnstimeofday(struct timespec *ts)
 	WARN_ON(timekeeping_suspended);
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		*ts = timekeeper.xtime;
 		nsecs = timekeeping_get_ns();
@@ -236,7 +238,7 @@ void getnstimeofday(struct timespec *ts)
 		/* If arch requires, add in gettimeoffset() */
 		nsecs += arch_gettimeoffset();
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	timespec_add_ns(ts, nsecs);
 }
@@ -251,7 +253,7 @@ ktime_t ktime_get(void)
 	WARN_ON(timekeeping_suspended);
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		secs = timekeeper.xtime.tv_sec +
 				timekeeper.wall_to_monotonic.tv_sec;
 		nsecs = timekeeper.xtime.tv_nsec +
@@ -260,7 +262,7 @@ ktime_t ktime_get(void)
 		/* If arch requires, add in gettimeoffset() */
 		nsecs += arch_gettimeoffset();
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 	/*
 	 * Use ktime_set/ktime_add_ns to create a proper ktime on
 	 * 32-bit architectures without CONFIG_KTIME_SCALAR.
@@ -286,14 +288,14 @@ void ktime_get_ts(struct timespec *ts)
 	WARN_ON(timekeeping_suspended);
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		*ts = timekeeper.xtime;
 		tomono = timekeeper.wall_to_monotonic;
 		nsecs = timekeeping_get_ns();
 		/* If arch requires, add in gettimeoffset() */
 		nsecs += arch_gettimeoffset();
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
 				ts->tv_nsec + tomono.tv_nsec + nsecs);
@@ -321,7 +323,7 @@ void getnstime_raw_and_real(struct times
 	do {
 		u32 arch_offset;
 
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		*ts_raw = timekeeper.raw_time;
 		*ts_real = timekeeper.xtime;
@@ -334,7 +336,7 @@ void getnstime_raw_and_real(struct times
 		nsecs_raw += arch_offset;
 		nsecs_real += arch_offset;
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	timespec_add_ns(ts_raw, nsecs_raw);
 	timespec_add_ns(ts_real, nsecs_real);
@@ -373,7 +375,8 @@ int do_settimeofday(const struct timespe
 	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 		return -EINVAL;
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	timekeeping_forward_now();
 
@@ -385,7 +388,8 @@ int do_settimeofday(const struct timespe
 	timekeeper.xtime = *tv;
 	timekeeping_update(true);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -409,7 +413,8 @@ int timekeeping_inject_offset(struct tim
 	if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
 		return -EINVAL;
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	timekeeping_forward_now();
 
@@ -419,7 +424,8 @@ int timekeeping_inject_offset(struct tim
 
 	timekeeping_update(true);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -440,7 +446,8 @@ static int change_clocksource(void *data
 
 	new = (struct clocksource *) data;
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	timekeeping_forward_now();
 	if (!new->enable || new->enable(new) == 0) {
@@ -451,7 +458,8 @@ static int change_clocksource(void *data
 	}
 	timekeeping_update(true);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	return 0;
 }
@@ -498,11 +506,11 @@ void getrawmonotonic(struct timespec *ts
 	s64 nsecs;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		nsecs = timekeeping_get_ns_raw();
 		*ts = timekeeper.raw_time;
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	timespec_add_ns(ts, nsecs);
 }
@@ -518,11 +526,11 @@ int timekeeping_valid_for_hres(void)
 	int ret;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		ret = timekeeper.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	return ret;
 }
@@ -535,11 +543,11 @@ u64 timekeeping_max_deferment(void)
 	unsigned long seq;
 	u64 ret;
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		ret = timekeeper.clock->max_idle_ns;
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	return ret;
 }
@@ -586,11 +594,13 @@ void __init timekeeping_init(void)
 	read_persistent_clock(&now);
 	read_boot_clock(&boot);
 
-	seqlock_init(&timekeeper.lock);
+	raw_spin_lock_init(&timekeeper.lock);
+	seqcount_init(&timekeeper.seq);
 
 	ntp_init();
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 	clock = clocksource_default_clock();
 	if (clock->enable)
 		clock->enable(clock);
@@ -608,7 +618,8 @@ void __init timekeeping_init(void)
 				-boot.tv_sec, -boot.tv_nsec);
 	timekeeper.total_sleep_time.tv_sec = 0;
 	timekeeper.total_sleep_time.tv_nsec = 0;
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 }
 
 /* time in seconds when suspend began */
@@ -657,7 +668,8 @@ void timekeeping_inject_sleeptime(struct
 	if (!(ts.tv_sec == 0 && ts.tv_nsec == 0))
 		return;
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	timekeeping_forward_now();
 
@@ -665,7 +677,8 @@ void timekeeping_inject_sleeptime(struct
 
 	timekeeping_update(true);
 
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	/* signal hrtimers about time change */
 	clock_was_set();
@@ -688,7 +701,8 @@ static void timekeeping_resume(void)
 
 	clocksource_resume();
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
 		ts = timespec_sub(ts, timekeeping_suspend_time);
@@ -698,7 +712,8 @@ static void timekeeping_resume(void)
 	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
 	timekeeper.ntp_error = 0;
 	timekeeping_suspended = 0;
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	touch_softlockup_watchdog();
 
@@ -716,7 +731,8 @@ static int timekeeping_suspend(void)
 
 	read_persistent_clock(&timekeeping_suspend_time);
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 	timekeeping_forward_now();
 	timekeeping_suspended = 1;
 
@@ -739,7 +755,8 @@ static int timekeeping_suspend(void)
 		timekeeping_suspend_time =
 			timespec_add(timekeeping_suspend_time, delta_delta);
 	}
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 
 	clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
 	clocksource_suspend();
@@ -997,7 +1014,8 @@ static void update_wall_time(void)
 	int shift = 0, maxshift;
 	unsigned long flags;
 
-	write_seqlock_irqsave(&timekeeper.lock, flags);
+	raw_spin_lock_irqsave(&timekeeper.lock, flags);
+	write_seqcount_begin(&timekeeper.seq);
 
 	/* Make sure we're fully resumed: */
 	if (unlikely(timekeeping_suspended))
@@ -1084,8 +1102,8 @@ static void update_wall_time(void)
 	timekeeping_update(false);
 
 out:
-	write_sequnlock_irqrestore(&timekeeper.lock, flags);
-
+	write_seqcount_end(&timekeeper.seq);
+	raw_spin_unlock_irqrestore(&timekeeper.lock, flags);
 }
 
 /**
@@ -1131,13 +1149,13 @@ void get_monotonic_boottime(struct times
 	WARN_ON(timekeeping_suspended);
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		*ts = timekeeper.xtime;
 		tomono = timekeeper.wall_to_monotonic;
 		sleep = timekeeper.total_sleep_time;
 		nsecs = timekeeping_get_ns();
 
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec + sleep.tv_sec,
 			ts->tv_nsec + tomono.tv_nsec + sleep.tv_nsec + nsecs);
@@ -1188,10 +1206,10 @@ struct timespec current_kernel_time(void
 	unsigned long seq;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		now = timekeeper.xtime;
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	return now;
 }
@@ -1203,11 +1221,11 @@ struct timespec get_monotonic_coarse(voi
 	unsigned long seq;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 
 		now = timekeeper.xtime;
 		mono = timekeeper.wall_to_monotonic;
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	set_normalized_timespec(&now, now.tv_sec + mono.tv_sec,
 				now.tv_nsec + mono.tv_nsec);
@@ -1239,11 +1257,11 @@ void get_xtime_and_monotonic_and_sleep_o
 	unsigned long seq;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		*xtim = timekeeper.xtime;
 		*wtom = timekeeper.wall_to_monotonic;
 		*sleep = timekeeper.total_sleep_time;
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 }
 
 /**
@@ -1255,9 +1273,9 @@ ktime_t ktime_get_monotonic_offset(void)
 	struct timespec wtom;
 
 	do {
-		seq = read_seqbegin(&timekeeper.lock);
+		seq = read_seqcount_begin(&timekeeper.seq);
 		wtom = timekeeper.wall_to_monotonic;
-	} while (read_seqretry(&timekeeper.lock, seq));
+	} while (read_seqcount_retry(&timekeeper.seq, seq));
 
 	return timespec_to_ktime(wtom);
 }
@@ -1272,7 +1290,9 @@ EXPORT_SYMBOL_GPL(ktime_get_monotonic_of
  */
 void xtime_update(unsigned long ticks)
 {
-	write_seqlock(&xtime_lock);
+	raw_spin_lock(&xtime_lock);
+	write_seqcount_begin(&xtime_seq);
 	do_timer(ticks);
-	write_sequnlock(&xtime_lock);
+	write_seqcount_end(&xtime_seq);
+	raw_spin_unlock(&xtime_lock);
 }
Index: linux-3.4/drivers/idle/i7300_idle.c
===================================================================
--- linux-3.4.orig/drivers/idle/i7300_idle.c
+++ linux-3.4/drivers/idle/i7300_idle.c
@@ -75,7 +75,7 @@ static unsigned long past_skip;
 
 static struct pci_dev *fbd_dev;
 
-static spinlock_t i7300_idle_lock;
+static raw_spinlock_t i7300_idle_lock;
 static int i7300_idle_active;
 
 static u8 i7300_idle_thrtctl_saved;
@@ -457,7 +457,7 @@ static int i7300_idle_notifier(struct no
 		idle_begin_time = ktime_get();
 	}
 
-	spin_lock_irqsave(&i7300_idle_lock, flags);
+	raw_spin_lock_irqsave(&i7300_idle_lock, flags);
 	if (val == IDLE_START) {
 
 		cpumask_set_cpu(smp_processor_id(), idle_cpumask);
@@ -506,7 +506,7 @@ static int i7300_idle_notifier(struct no
 		}
 	}
 end:
-	spin_unlock_irqrestore(&i7300_idle_lock, flags);
+	raw_spin_unlock_irqrestore(&i7300_idle_lock, flags);
 	return 0;
 }
 
@@ -548,7 +548,7 @@ struct debugfs_file_info {
 
 static int __init i7300_idle_init(void)
 {
-	spin_lock_init(&i7300_idle_lock);
+	raw_spin_lock_init(&i7300_idle_lock);
 	total_us = 0;
 
 	if (i7300_idle_platform_probe(&fbd_dev, &ioat_dev, forceload))
Index: linux-3.4/kernel/signal.c
===================================================================
--- linux-3.4.orig/kernel/signal.c
+++ linux-3.4/kernel/signal.c
@@ -345,13 +345,45 @@ static bool task_participate_group_stop(
 	return false;
 }
 
+#ifdef __HAVE_ARCH_CMPXCHG
+static inline struct sigqueue *get_task_cache(struct task_struct *t)
+{
+	struct sigqueue *q = t->sigqueue_cache;
+
+	if (cmpxchg(&t->sigqueue_cache, q, NULL) != q)
+		return NULL;
+	return q;
+}
+
+static inline int put_task_cache(struct task_struct *t, struct sigqueue *q)
+{
+	if (cmpxchg(&t->sigqueue_cache, NULL, q) == NULL)
+		return 0;
+	return 1;
+}
+
+#else
+
+static inline struct sigqueue *get_task_cache(struct task_struct *t)
+{
+	return NULL;
+}
+
+static inline int put_task_cache(struct task_struct *t, struct sigqueue *q)
+{
+	return 1;
+}
+
+#endif
+
 /*
  * allocate a new signal queue record
  * - this may be called without locks if and only if t == current, otherwise an
  *   appropriate lock must be held to stop the target task from exiting
  */
 static struct sigqueue *
-__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
+__sigqueue_do_alloc(int sig, struct task_struct *t, gfp_t flags,
+		    int override_rlimit, int fromslab)
 {
 	struct sigqueue *q = NULL;
 	struct user_struct *user;
@@ -368,7 +400,10 @@ __sigqueue_alloc(int sig, struct task_st
 	if (override_rlimit ||
 	    atomic_read(&user->sigpending) <=
 			task_rlimit(t, RLIMIT_SIGPENDING)) {
-		q = kmem_cache_alloc(sigqueue_cachep, flags);
+		if (!fromslab)
+			q = get_task_cache(t);
+		if (!q)
+			q = kmem_cache_alloc(sigqueue_cachep, flags);
 	} else {
 		print_dropped_signal(sig);
 	}
@@ -385,6 +420,13 @@ __sigqueue_alloc(int sig, struct task_st
 	return q;
 }
 
+static struct sigqueue *
+__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags,
+		 int override_rlimit)
+{
+	return __sigqueue_do_alloc(sig, t, flags, override_rlimit, 0);
+}
+
 static void __sigqueue_free(struct sigqueue *q)
 {
 	if (q->flags & SIGQUEUE_PREALLOC)
@@ -394,6 +436,21 @@ static void __sigqueue_free(struct sigqu
 	kmem_cache_free(sigqueue_cachep, q);
 }
 
+static void sigqueue_free_current(struct sigqueue *q)
+{
+	struct user_struct *up;
+
+	if (q->flags & SIGQUEUE_PREALLOC)
+		return;
+
+	up = q->user;
+	if (rt_prio(current->normal_prio) && !put_task_cache(current, q)) {
+		atomic_dec(&up->sigpending);
+		free_uid(up);
+	} else
+		  __sigqueue_free(q);
+}
+
 void flush_sigqueue(struct sigpending *queue)
 {
 	struct sigqueue *q;
@@ -407,6 +464,21 @@ void flush_sigqueue(struct sigpending *q
 }
 
 /*
+ * Called from __exit_signal. Flush tsk->pending and
+ * tsk->sigqueue_cache
+ */
+void flush_task_sigqueue(struct task_struct *tsk)
+{
+	struct sigqueue *q;
+
+	flush_sigqueue(&tsk->pending);
+
+	q = get_task_cache(tsk);
+	if (q)
+		kmem_cache_free(sigqueue_cachep, q);
+}
+
+/*
  * Flush all pending signals for a task.
  */
 void __flush_signals(struct task_struct *t)
@@ -555,7 +627,7 @@ static void collect_signal(int sig, stru
 still_pending:
 		list_del_init(&first->list);
 		copy_siginfo(info, &first->info);
-		__sigqueue_free(first);
+		sigqueue_free_current(first);
 	} else {
 		/*
 		 * Ok, it wasn't in the queue.  This must be
@@ -601,6 +673,8 @@ int dequeue_signal(struct task_struct *t
 {
 	int signr;
 
+	WARN_ON_ONCE(tsk != current);
+
 	/* We only dequeue private signals from ourselves, we don't let
 	 * signalfd steal them
 	 */
@@ -683,6 +757,9 @@ void signal_wake_up(struct task_struct *
 
 	set_tsk_thread_flag(t, TIF_SIGPENDING);
 
+	if (unlikely(t == current))
+		return;
+
 	/*
 	 * For SIGKILL, we want to wake it up in the stopped/traced/killable
 	 * case. We don't check t->state here because there is a race with it
@@ -1235,8 +1312,8 @@ int do_send_sig_info(int sig, struct sig
  * We don't want to have recursive SIGSEGV's etc, for example,
  * that is why we also clear SIGNAL_UNKILLABLE.
  */
-int
-force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+static int
+do_force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
 {
 	unsigned long int flags;
 	int ret, blocked, ignored;
@@ -1261,6 +1338,39 @@ force_sig_info(int sig, struct siginfo *
 	return ret;
 }
 
+int force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+{
+/*
+ * On some archs, PREEMPT_RT has to delay sending a signal from a trap
+ * since it can not enable preemption, and the signal code's spin_locks
+ * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will
+ * send the signal on exit of the trap.
+ */
+#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+	if (in_atomic()) {
+		if (WARN_ON_ONCE(t != current))
+			return 0;
+		if (WARN_ON_ONCE(t->forced_info.si_signo))
+			return 0;
+
+		if (is_si_special(info)) {
+			WARN_ON_ONCE(info != SEND_SIG_PRIV);
+			t->forced_info.si_signo = sig;
+			t->forced_info.si_errno = 0;
+			t->forced_info.si_code = SI_KERNEL;
+			t->forced_info.si_pid = 0;
+			t->forced_info.si_uid = 0;
+		} else {
+			t->forced_info = *info;
+		}
+
+		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+		return 0;
+	}
+#endif
+	return do_force_sig_info(sig, info, t);
+}
+
 /*
  * Nuke all other threads in the group.
  */
@@ -1291,12 +1401,12 @@ struct sighand_struct *__lock_task_sigha
 	struct sighand_struct *sighand;
 
 	for (;;) {
-		local_irq_save(*flags);
+		local_irq_save_nort(*flags);
 		rcu_read_lock();
 		sighand = rcu_dereference(tsk->sighand);
 		if (unlikely(sighand == NULL)) {
 			rcu_read_unlock();
-			local_irq_restore(*flags);
+			local_irq_restore_nort(*flags);
 			break;
 		}
 
@@ -1307,7 +1417,7 @@ struct sighand_struct *__lock_task_sigha
 		}
 		spin_unlock(&sighand->siglock);
 		rcu_read_unlock();
-		local_irq_restore(*flags);
+		local_irq_restore_nort(*flags);
 	}
 
 	return sighand;
@@ -1554,7 +1664,8 @@ EXPORT_SYMBOL(kill_pid);
  */
 struct sigqueue *sigqueue_alloc(void)
 {
-	struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
+	/* Preallocated sigqueue objects always from the slabcache ! */
+	struct sigqueue *q = __sigqueue_do_alloc(-1, current, GFP_KERNEL, 0, 1);
 
 	if (q)
 		q->flags |= SIGQUEUE_PREALLOC;
@@ -1909,15 +2020,7 @@ static void ptrace_stop(int exit_code, i
 		if (gstop_done && ptrace_reparented(current))
 			do_notify_parent_cldstop(current, false, why);
 
-		/*
-		 * Don't want to allow preemption here, because
-		 * sys_ptrace() needs this task to be inactive.
-		 *
-		 * XXX: implement read_unlock_no_resched().
-		 */
-		preempt_disable();
 		read_unlock(&tasklist_lock);
-		preempt_enable_no_resched();
 		schedule();
 	} else {
 		/*
Index: linux-3.4/arch/arm/kernel/perf_event.c
===================================================================
--- linux-3.4.orig/arch/arm/kernel/perf_event.c
+++ linux-3.4/arch/arm/kernel/perf_event.c
@@ -433,7 +433,7 @@ armpmu_reserve_hardware(struct arm_pmu *
 		}
 
 		err = request_irq(irq, handle_irq,
-				  IRQF_DISABLED | IRQF_NOBALANCING,
+				  IRQF_NOBALANCING | IRQF_NO_THREAD,
 				  "arm-pmu", armpmu);
 		if (err) {
 			pr_err("unable to request IRQ%d for ARM PMU counters\n",
Index: linux-3.4/arch/arm/Kconfig
===================================================================
--- linux-3.4.orig/arch/arm/Kconfig
+++ linux-3.4/arch/arm/Kconfig
@@ -31,6 +31,7 @@ config ARM
 	select HAVE_C_RECORDMCOUNT
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_IRQ_SHOW
+	select IRQ_FORCED_THREADING
 	select CPU_PM if (SUSPEND || CPU_IDLE)
 	select GENERIC_PCI_IOMAP
 	select HAVE_BPF_JIT if NET
@@ -1715,7 +1716,7 @@ config HAVE_ARCH_PFN_VALID
 
 config HIGHMEM
 	bool "High Memory Support"
-	depends on MMU
+	depends on MMU && !PREEMPT_RT_FULL
 	help
 	  The address space of ARM processors is only 4 Gigabytes large
 	  and it has to accommodate user address space, kernel address
Index: linux-3.4/arch/arm/mach-exynos/platsmp.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-exynos/platsmp.c
+++ linux-3.4/arch/arm/mach-exynos/platsmp.c
@@ -62,7 +62,7 @@ static void __iomem *scu_base_addr(void)
 	return (void __iomem *)(S5P_VA_SCU);
 }
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
@@ -82,8 +82,8 @@ void __cpuinit platform_secondary_init(u
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -94,7 +94,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * Set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * The secondary processor is waiting to be released from
@@ -123,7 +123,7 @@ int __cpuinit boot_secondary(unsigned in
 
 		if (timeout == 0) {
 			printk(KERN_ERR "cpu1 power enable failed");
-			spin_unlock(&boot_lock);
+			raw_spin_unlock(&boot_lock);
 			return -ETIMEDOUT;
 		}
 	}
@@ -151,7 +151,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return pen_release != -1 ? -ENOSYS : 0;
 }
Index: linux-3.4/arch/arm/mach-msm/platsmp.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-msm/platsmp.c
+++ linux-3.4/arch/arm/mach-msm/platsmp.c
@@ -40,7 +40,7 @@ extern void msm_secondary_startup(void);
  */
 volatile int pen_release = -1;
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 static inline int get_core_count(void)
 {
@@ -70,8 +70,8 @@ void __cpuinit platform_secondary_init(u
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 static __cpuinit void prepare_cold_cpu(unsigned int cpu)
@@ -108,7 +108,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * The secondary processor is waiting to be released from
@@ -142,7 +142,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return pen_release != -1 ? -ENOSYS : 0;
 }
Index: linux-3.4/arch/arm/mach-omap2/omap-smp.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-omap2/omap-smp.c
+++ linux-3.4/arch/arm/mach-omap2/omap-smp.c
@@ -34,7 +34,7 @@
 /* SCU base address */
 static void __iomem *scu_base;
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 void __iomem *omap4_get_scu_base(void)
 {
@@ -65,8 +65,8 @@ void __cpuinit platform_secondary_init(u
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -77,7 +77,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * Set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * Update the AuxCoreBoot0 with boot state for secondary core.
@@ -117,7 +117,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * Now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return 0;
 }
Index: linux-3.4/arch/arm/mach-ux500/platsmp.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-ux500/platsmp.c
+++ linux-3.4/arch/arm/mach-ux500/platsmp.c
@@ -58,7 +58,7 @@ static void __iomem *scu_base_addr(void)
 	return NULL;
 }
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
@@ -78,8 +78,8 @@ void __cpuinit platform_secondary_init(u
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -90,7 +90,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * The secondary processor is waiting to be released from
@@ -111,7 +111,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return pen_release != -1 ? -ENOSYS : 0;
 }
Index: linux-3.4/arch/arm/plat-versatile/platsmp.c
===================================================================
--- linux-3.4.orig/arch/arm/plat-versatile/platsmp.c
+++ linux-3.4/arch/arm/plat-versatile/platsmp.c
@@ -38,7 +38,7 @@ static void __cpuinit write_pen_release(
 	outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1));
 }
 
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
 
 void __cpuinit platform_secondary_init(unsigned int cpu)
 {
@@ -58,8 +58,8 @@ void __cpuinit platform_secondary_init(u
 	/*
 	 * Synchronise with the boot thread.
 	 */
-	spin_lock(&boot_lock);
-	spin_unlock(&boot_lock);
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 }
 
 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -70,7 +70,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * Set synchronisation state between this boot processor
 	 * and the secondary one
 	 */
-	spin_lock(&boot_lock);
+	raw_spin_lock(&boot_lock);
 
 	/*
 	 * This is really belt and braces; we hold unintended secondary
@@ -100,7 +100,7 @@ int __cpuinit boot_secondary(unsigned in
 	 * now the secondary core is starting up let it run its
 	 * calibrations, then wait for it to finish
 	 */
-	spin_unlock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
 
 	return pen_release != -1 ? -ENOSYS : 0;
 }
Index: linux-3.4/arch/arm/mach-omap2/omap-wakeupgen.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-omap2/omap-wakeupgen.c
+++ linux-3.4/arch/arm/mach-omap2/omap-wakeupgen.c
@@ -43,7 +43,7 @@
 
 static void __iomem *wakeupgen_base;
 static void __iomem *sar_base;
-static DEFINE_SPINLOCK(wakeupgen_lock);
+static DEFINE_RAW_SPINLOCK(wakeupgen_lock);
 static unsigned int irq_target_cpu[NR_IRQS];
 
 /*
@@ -128,9 +128,9 @@ static void wakeupgen_mask(struct irq_da
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&wakeupgen_lock, flags);
+	raw_spin_lock_irqsave(&wakeupgen_lock, flags);
 	_wakeupgen_clear(d->irq, irq_target_cpu[d->irq]);
-	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+	raw_spin_unlock_irqrestore(&wakeupgen_lock, flags);
 }
 
 /*
@@ -140,9 +140,9 @@ static void wakeupgen_unmask(struct irq_
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&wakeupgen_lock, flags);
+	raw_spin_lock_irqsave(&wakeupgen_lock, flags);
 	_wakeupgen_set(d->irq, irq_target_cpu[d->irq]);
-	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+	raw_spin_unlock_irqrestore(&wakeupgen_lock, flags);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -183,7 +183,7 @@ static void wakeupgen_irqmask_all(unsign
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&wakeupgen_lock, flags);
+	raw_spin_lock_irqsave(&wakeupgen_lock, flags);
 	if (set) {
 		_wakeupgen_save_masks(cpu);
 		_wakeupgen_set_all(cpu, WKG_MASK_ALL);
@@ -191,7 +191,7 @@ static void wakeupgen_irqmask_all(unsign
 		_wakeupgen_set_all(cpu, WKG_UNMASK_ALL);
 		_wakeupgen_restore_masks(cpu);
 	}
-	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+	raw_spin_unlock_irqrestore(&wakeupgen_lock, flags);
 }
 #endif
 
Index: linux-3.4/kernel/posix-timers.c
===================================================================
--- linux-3.4.orig/kernel/posix-timers.c
+++ linux-3.4/kernel/posix-timers.c
@@ -439,6 +439,7 @@ static enum hrtimer_restart posix_timer_
 static struct pid *good_sigevent(sigevent_t * event)
 {
 	struct task_struct *rtn = current->group_leader;
+	int sig = event->sigev_signo;
 
 	if ((event->sigev_notify & SIGEV_THREAD_ID ) &&
 		(!(rtn = find_task_by_vpid(event->sigev_notify_thread_id)) ||
@@ -447,7 +448,8 @@ static struct pid *good_sigevent(sigeven
 		return NULL;
 
 	if (((event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) &&
-	    ((event->sigev_signo <= 0) || (event->sigev_signo > SIGRTMAX)))
+	    (sig <= 0 || sig > SIGRTMAX || sig_kernel_only(sig) ||
+	     sig_kernel_coredump(sig)))
 		return NULL;
 
 	return task_pid(rtn);
@@ -764,6 +766,20 @@ SYSCALL_DEFINE1(timer_getoverrun, timer_
 	return overrun;
 }
 
+/*
+ * Protected by RCU!
+ */
+static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr)
+{
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (kc->timer_set == common_timer_set)
+		hrtimer_wait_for_timer(&timr->it.real.timer);
+	else
+		/* FIXME: Whacky hack for posix-cpu-timers */
+		schedule_timeout(1);
+#endif
+}
+
 /* Set a POSIX.1b interval timer. */
 /* timr->it_lock is taken. */
 static int
@@ -841,6 +857,7 @@ retry:
 	if (!timr)
 		return -EINVAL;
 
+	rcu_read_lock();
 	kc = clockid_to_kclock(timr->it_clock);
 	if (WARN_ON_ONCE(!kc || !kc->timer_set))
 		error = -EINVAL;
@@ -849,9 +866,12 @@ retry:
 
 	unlock_timer(timr, flag);
 	if (error == TIMER_RETRY) {
+		timer_wait_for_callback(kc, timr);
 		rtn = NULL;	// We already got the old time...
+		rcu_read_unlock();
 		goto retry;
 	}
+	rcu_read_unlock();
 
 	if (old_setting && !error &&
 	    copy_to_user(old_setting, &old_spec, sizeof (old_spec)))
@@ -889,10 +909,15 @@ retry_delete:
 	if (!timer)
 		return -EINVAL;
 
+	rcu_read_lock();
 	if (timer_delete_hook(timer) == TIMER_RETRY) {
 		unlock_timer(timer, flags);
+		timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
+					timer);
+		rcu_read_unlock();
 		goto retry_delete;
 	}
+	rcu_read_unlock();
 
 	spin_lock(&current->sighand->siglock);
 	list_del(&timer->list);
@@ -918,8 +943,18 @@ static void itimer_delete(struct k_itime
 retry_delete:
 	spin_lock_irqsave(&timer->it_lock, flags);
 
+	/* On RT we can race with a deletion */
+	if (!timer->it_signal) {
+		unlock_timer(timer, flags);
+		return;
+	}
+
 	if (timer_delete_hook(timer) == TIMER_RETRY) {
+		rcu_read_lock();
 		unlock_timer(timer, flags);
+		timer_wait_for_callback(clockid_to_kclock(timer->it_clock),
+					timer);
+		rcu_read_unlock();
 		goto retry_delete;
 	}
 	list_del(&timer->list);
Index: linux-3.4/include/linux/sched.h
===================================================================
--- linux-3.4.orig/include/linux/sched.h
+++ linux-3.4/include/linux/sched.h
@@ -63,6 +63,7 @@ struct sched_param {
 #include <linux/nodemask.h>
 #include <linux/mm_types.h>
 
+#include <asm/kmap_types.h>
 #include <asm/page.h>
 #include <asm/ptrace.h>
 #include <asm/cputime.h>
@@ -90,6 +91,7 @@ struct sched_param {
 #include <linux/latencytop.h>
 #include <linux/cred.h>
 #include <linux/llist.h>
+#include <linux/hardirq.h>
 
 #include <asm/processor.h>
 
@@ -1108,6 +1110,7 @@ struct sched_domain;
 #define WF_SYNC		0x01		/* waker goes to sleep after wakup */
 #define WF_FORK		0x02		/* child wakeup after fork */
 #define WF_MIGRATED	0x04		/* internal use, task got migrated */
+#define WF_LOCK_SLEEPER	0x08		/* wakeup spinlock "sleeper" */
 
 #define ENQUEUE_WAKEUP		1
 #define ENQUEUE_HEAD		2
@@ -1263,6 +1266,7 @@ enum perf_event_task_context {
 
 struct task_struct {
 	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
+	volatile long saved_state;	/* saved state for "spinlock sleepers" */
 	void *stack;
 	atomic_t usage;
 	unsigned int flags;	/* per process flags, defined below */
@@ -1299,6 +1303,12 @@ struct task_struct {
 #endif
 
 	unsigned int policy;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	int migrate_disable;
+#ifdef CONFIG_SCHED_DEBUG
+	int migrate_disable_atomic;
+#endif
+#endif
 	cpumask_t cpus_allowed;
 
 #ifdef CONFIG_PREEMPT_RCU
@@ -1402,6 +1412,9 @@ struct task_struct {
 
 	struct task_cputime cputime_expires;
 	struct list_head cpu_timers[3];
+#ifdef CONFIG_PREEMPT_RT_BASE
+	struct task_struct *posix_timer_list;
+#endif
 
 /* process credentials */
 	const struct cred __rcu *real_cred; /* objective and real subjective task
@@ -1435,10 +1448,15 @@ struct task_struct {
 /* signal handlers */
 	struct signal_struct *signal;
 	struct sighand_struct *sighand;
+	struct sigqueue *sigqueue_cache;
 
 	sigset_t blocked, real_blocked;
 	sigset_t saved_sigmask;	/* restored if set_restore_sigmask() was used */
 	struct sigpending pending;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	/* TODO: move me into ->restart_block ? */
+	struct siginfo forced_info;
+#endif
 
 	unsigned long sas_ss_sp;
 	size_t sas_ss_size;
@@ -1473,6 +1491,9 @@ struct task_struct {
 	/* mutex deadlock detection */
 	struct mutex_waiter *blocked_on;
 #endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+	int pagefault_disabled;
+#endif
 #ifdef CONFIG_TRACE_IRQFLAGS
 	unsigned int irq_events;
 	unsigned long hardirq_enable_ip;
@@ -1605,6 +1626,12 @@ struct task_struct {
 	unsigned long trace;
 	/* bitmask and counter of trace recursion */
 	unsigned long trace_recursion;
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+	u64 preempt_timestamp_hist;
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+	unsigned long timer_offset;
+#endif
+#endif
 #endif /* CONFIG_TRACING */
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
 	struct memcg_batch_info {
@@ -1617,10 +1644,26 @@ struct task_struct {
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	atomic_t ptrace_bp_refcnt;
 #endif
+#ifdef CONFIG_PREEMPT_RT_BASE
+	struct rcu_head put_rcu;
+	int softirq_nestcnt;
+#endif
+#if defined CONFIG_PREEMPT_RT_FULL && defined CONFIG_HIGHMEM
+	int kmap_idx;
+	pte_t kmap_pte[KM_TYPE_NR];
+#endif
 };
 
-/* Future-safe accessor for struct task_struct's cpus_allowed. */
-#define tsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
+#ifdef CONFIG_PREEMPT_RT_FULL
+static inline bool cur_pf_disabled(void) { return current->pagefault_disabled; }
+#else
+static inline bool cur_pf_disabled(void) { return false; }
+#endif
+
+static inline bool pagefault_disabled(void)
+{
+	return in_atomic() || cur_pf_disabled();
+}
 
 /*
  * Priority of a process goes from 0..MAX_PRIO-1, valid RT
@@ -1790,6 +1833,15 @@ extern struct pid *cad_pid;
 extern void free_task(struct task_struct *tsk);
 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+extern void __put_task_struct_cb(struct rcu_head *rhp);
+
+static inline void put_task_struct(struct task_struct *t)
+{
+	if (atomic_dec_and_test(&t->usage))
+		call_rcu(&t->put_rcu, __put_task_struct_cb);
+}
+#else
 extern void __put_task_struct(struct task_struct *t);
 
 static inline void put_task_struct(struct task_struct *t)
@@ -1797,6 +1849,7 @@ static inline void put_task_struct(struc
 	if (atomic_dec_and_test(&t->usage))
 		__put_task_struct(t);
 }
+#endif
 
 extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
 extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st);
@@ -1820,6 +1873,7 @@ extern void thread_group_times(struct ta
 #define PF_FROZEN	0x00010000	/* frozen for system suspend */
 #define PF_FSTRANS	0x00020000	/* inside a filesystem transaction */
 #define PF_KSWAPD	0x00040000	/* I am kswapd */
+#define PF_STOMPER	0x00080000	/* I am a stomp machine thread */
 #define PF_LESS_THROTTLE 0x00100000	/* Throttle me less: I clean memory */
 #define PF_KTHREAD	0x00200000	/* I am a kernel thread */
 #define PF_RANDOMIZE	0x00400000	/* randomize virtual address space */
@@ -2192,6 +2246,7 @@ extern void xtime_update(unsigned long t
 
 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
 extern int wake_up_process(struct task_struct *tsk);
+extern int wake_up_lock_sleeper(struct task_struct * tsk);
 extern void wake_up_new_task(struct task_struct *tsk);
 #ifdef CONFIG_SMP
  extern void kick_process(struct task_struct *tsk);
@@ -2282,12 +2337,24 @@ extern struct mm_struct * mm_alloc(void)
 
 /* mmdrop drops the mm and the page tables */
 extern void __mmdrop(struct mm_struct *);
+
 static inline void mmdrop(struct mm_struct * mm)
 {
 	if (unlikely(atomic_dec_and_test(&mm->mm_count)))
 		__mmdrop(mm);
 }
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+extern void __mmdrop_delayed(struct rcu_head *rhp);
+static inline void mmdrop_delayed(struct mm_struct *mm)
+{
+	if (atomic_dec_and_test(&mm->mm_count))
+		call_rcu(&mm->delayed_drop, __mmdrop_delayed);
+}
+#else
+# define mmdrop_delayed(mm)	mmdrop(mm)
+#endif
+
 /* mmput gets rid of the mappings and all user-space */
 extern void mmput(struct mm_struct *);
 /* Grab a reference to a task's mm, if it is not already going away */
@@ -2632,7 +2699,7 @@ extern int _cond_resched(void);
 
 extern int __cond_resched_lock(spinlock_t *lock);
 
-#ifdef CONFIG_PREEMPT_COUNT
+#if defined(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT_FULL)
 #define PREEMPT_LOCK_OFFSET	PREEMPT_OFFSET
 #else
 #define PREEMPT_LOCK_OFFSET	0
@@ -2643,12 +2710,16 @@ extern int __cond_resched_lock(spinlock_
 	__cond_resched_lock(lock);				\
 })
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 extern int __cond_resched_softirq(void);
 
 #define cond_resched_softirq() ({					\
 	__might_sleep(__FILE__, __LINE__, SOFTIRQ_DISABLE_OFFSET);	\
 	__cond_resched_softirq();					\
 })
+#else
+# define cond_resched_softirq()		cond_resched()
+#endif
 
 /*
  * Does a critical section need to be broken due to another
@@ -2711,6 +2782,26 @@ static inline void set_task_cpu(struct t
 
 #endif /* CONFIG_SMP */
 
+static inline int __migrate_disabled(struct task_struct *p)
+{
+#ifdef CONFIG_PREEMPT_RT_FULL
+	return p->migrate_disable;
+#else
+	return 0;
+#endif
+}
+
+/* Future-safe accessor for struct task_struct's cpus_allowed. */
+static inline const struct cpumask *tsk_cpus_allowed(struct task_struct *p)
+{
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (p->migrate_disable)
+		return cpumask_of(task_cpu(p));
+#endif
+
+	return &p->cpus_allowed;
+}
+
 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
 
Index: linux-3.4/include/linux/signal.h
===================================================================
--- linux-3.4.orig/include/linux/signal.h
+++ linux-3.4/include/linux/signal.h
@@ -229,6 +229,7 @@ static inline void init_sigpending(struc
 }
 
 extern void flush_sigqueue(struct sigpending *queue);
+extern void flush_task_sigqueue(struct task_struct *tsk);
 
 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
 static inline int valid_signal(unsigned long sig)
Index: linux-3.4/kernel/exit.c
===================================================================
--- linux-3.4.orig/kernel/exit.c
+++ linux-3.4/kernel/exit.c
@@ -143,7 +143,7 @@ static void __exit_signal(struct task_st
 	 * Do this under ->siglock, we can race with another thread
 	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
 	 */
-	flush_sigqueue(&tsk->pending);
+	flush_task_sigqueue(tsk);
 	tsk->sighand = NULL;
 	spin_unlock(&sighand->siglock);
 
Index: linux-3.4/kernel/fork.c
===================================================================
--- linux-3.4.orig/kernel/fork.c
+++ linux-3.4/kernel/fork.c
@@ -90,7 +90,7 @@ int max_threads;		/* tunable limit on nr
 
 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
 
-__cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */
+DEFINE_RWLOCK(tasklist_lock);  /* outer */
 
 #ifdef CONFIG_PROVE_RCU
 int lockdep_tasklist_lock_is_held(void)
@@ -201,7 +201,18 @@ void __put_task_struct(struct task_struc
 	if (!profile_handoff_task(tsk))
 		free_task(tsk);
 }
+#ifndef CONFIG_PREEMPT_RT_BASE
 EXPORT_SYMBOL_GPL(__put_task_struct);
+#else
+void __put_task_struct_cb(struct rcu_head *rhp)
+{
+	struct task_struct *tsk = container_of(rhp, struct task_struct, put_rcu);
+
+	__put_task_struct(tsk);
+
+}
+EXPORT_SYMBOL_GPL(__put_task_struct_cb);
+#endif
 
 /*
  * macro override instead of weak attribute alias, to workaround
@@ -561,6 +572,19 @@ void __mmdrop(struct mm_struct *mm)
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+/*
+ * RCU callback for delayed mm drop. Not strictly rcu, but we don't
+ * want another facility to make this work.
+ */
+void __mmdrop_delayed(struct rcu_head *rhp)
+{
+	struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop);
+
+	__mmdrop(mm);
+}
+#endif
+
 /*
  * Decrement the use count and release all resources for an mm.
  */
@@ -1096,6 +1120,9 @@ void mm_init_owner(struct mm_struct *mm,
  */
 static void posix_cpu_timers_init(struct task_struct *tsk)
 {
+#ifdef CONFIG_PREEMPT_RT_BASE
+	tsk->posix_timer_list = NULL;
+#endif
 	tsk->cputime_expires.prof_exp = 0;
 	tsk->cputime_expires.virt_exp = 0;
 	tsk->cputime_expires.sched_exp = 0;
@@ -1204,6 +1231,7 @@ static struct task_struct *copy_process(
 	spin_lock_init(&p->alloc_lock);
 
 	init_sigpending(&p->pending);
+	p->sigqueue_cache = NULL;
 
 	p->utime = p->stime = p->gtime = 0;
 	p->utimescaled = p->stimescaled = 0;
@@ -1262,6 +1290,9 @@ static struct task_struct *copy_process(
 	p->hardirq_context = 0;
 	p->softirq_context = 0;
 #endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+	p->pagefault_disabled = 0;
+#endif
 #ifdef CONFIG_LOCKDEP
 	p->lockdep_depth = 0; /* no locks held yet */
 	p->curr_chain_key = 0;
Index: linux-3.4/arch/x86/include/asm/signal.h
===================================================================
--- linux-3.4.orig/arch/x86/include/asm/signal.h
+++ linux-3.4/arch/x86/include/asm/signal.h
@@ -31,6 +31,19 @@ typedef struct {
 	unsigned long sig[_NSIG_WORDS];
 } sigset_t;
 
+/*
+ * Because some traps use the IST stack, we must keep
+ * preemption disabled while calling do_trap(), but do_trap()
+ * may call force_sig_info() which will grab the signal spin_locks
+ * for the task, which in PREEMPT_RT_FULL are mutexes.
+ * By defining ARCH_RT_DELAYS_SIGNAL_SEND the force_sig_info() will
+ * set TIF_NOTIFY_RESUME and set up the signal to be sent on exit
+ * of the trap.
+ */
+#if defined(CONFIG_PREEMPT_RT_FULL) && defined(CONFIG_X86_64)
+#define ARCH_RT_DELAYS_SIGNAL_SEND
+#endif
+
 #else
 /* Here we must cater to libcs that poke about in kernel headers.  */
 
Index: linux-3.4/arch/x86/kernel/signal.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/signal.c
+++ linux-3.4/arch/x86/kernel/signal.c
@@ -824,6 +824,15 @@ do_notify_resume(struct pt_regs *regs, v
 		mce_notify_process();
 #endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
 
+#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+	if (unlikely(current->forced_info.si_signo)) {
+		struct task_struct *t = current;
+		force_sig_info(t->forced_info.si_signo,
+					&t->forced_info, t);
+		t->forced_info.si_signo = 0;
+	}
+#endif
+
 	/* deal with pending signal delivery */
 	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);
Index: linux-3.4/include/asm-generic/cmpxchg-local.h
===================================================================
--- linux-3.4.orig/include/asm-generic/cmpxchg-local.h
+++ linux-3.4/include/asm-generic/cmpxchg-local.h
@@ -21,7 +21,7 @@ static inline unsigned long __cmpxchg_lo
 	if (size == 8 && sizeof(unsigned long) != 8)
 		wrong_size_cmpxchg(ptr);
 
-	local_irq_save(flags);
+	raw_local_irq_save(flags);
 	switch (size) {
 	case 1: prev = *(u8 *)ptr;
 		if (prev == old)
@@ -42,7 +42,7 @@ static inline unsigned long __cmpxchg_lo
 	default:
 		wrong_size_cmpxchg(ptr);
 	}
-	local_irq_restore(flags);
+	raw_local_irq_restore(flags);
 	return prev;
 }
 
@@ -55,11 +55,11 @@ static inline u64 __cmpxchg64_local_gene
 	u64 prev;
 	unsigned long flags;
 
-	local_irq_save(flags);
+	raw_local_irq_save(flags);
 	prev = *(u64 *)ptr;
 	if (prev == old)
 		*(u64 *)ptr = new;
-	local_irq_restore(flags);
+	raw_local_irq_restore(flags);
 	return prev;
 }
 
Index: linux-3.4/drivers/char/random.c
===================================================================
--- linux-3.4.orig/drivers/char/random.c
+++ linux-3.4/drivers/char/random.c
@@ -433,7 +433,7 @@ static struct entropy_store input_pool =
 	.poolinfo = &poolinfo_table[0],
 	.name = "input",
 	.limit = 1,
-	.lock = __SPIN_LOCK_UNLOCKED(&input_pool.lock),
+	.lock = __SPIN_LOCK_UNLOCKED(input_pool.lock),
 	.pool = input_pool_data
 };
 
@@ -442,7 +442,7 @@ static struct entropy_store blocking_poo
 	.name = "blocking",
 	.limit = 1,
 	.pull = &input_pool,
-	.lock = __SPIN_LOCK_UNLOCKED(&blocking_pool.lock),
+	.lock = __SPIN_LOCK_UNLOCKED(blocking_pool.lock),
 	.pool = blocking_pool_data
 };
 
@@ -450,7 +450,7 @@ static struct entropy_store nonblocking_
 	.poolinfo = &poolinfo_table[1],
 	.name = "nonblocking",
 	.pull = &input_pool,
-	.lock = __SPIN_LOCK_UNLOCKED(&nonblocking_pool.lock),
+	.lock = __SPIN_LOCK_UNLOCKED(nonblocking_pool.lock),
 	.pool = nonblocking_pool_data
 };
 
@@ -633,8 +633,11 @@ static void add_timer_randomness(struct 
 	preempt_disable();
 	/* if over the trickle threshold, use only 1 in 4096 samples */
 	if (input_pool.entropy_count > trickle_thresh &&
-	    ((__this_cpu_inc_return(trickle_count) - 1) & 0xfff))
-		goto out;
+	    ((__this_cpu_inc_return(trickle_count) - 1) & 0xfff)) {
+		preempt_enable();
+		return;
+	}
+	preempt_enable();
 
 	sample.jiffies = jiffies;
 
@@ -680,8 +683,6 @@ static void add_timer_randomness(struct 
 		credit_entropy_bits(&input_pool,
 				    min_t(int, fls(delta>>1), 11));
 	}
-out:
-	preempt_enable();
 }
 
 void add_input_randomness(unsigned int type, unsigned int code,
Index: linux-3.4/arch/arm/mach-at91/at91rm9200_time.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-at91/at91rm9200_time.c
+++ linux-3.4/arch/arm/mach-at91/at91rm9200_time.c
@@ -130,6 +130,7 @@ clkevt32k_mode(enum clock_event_mode mod
 		break;
 	case CLOCK_EVT_MODE_SHUTDOWN:
 	case CLOCK_EVT_MODE_UNUSED:
+		remove_irq(AT91_ID_SYS, &at91rm9200_timer_irq);
 	case CLOCK_EVT_MODE_RESUME:
 		irqmask = 0;
 		break;
Index: linux-3.4/arch/arm/mach-at91/at91sam926x_time.c
===================================================================
--- linux-3.4.orig/arch/arm/mach-at91/at91sam926x_time.c
+++ linux-3.4/arch/arm/mach-at91/at91sam926x_time.c
@@ -67,7 +67,7 @@ static struct clocksource pit_clk = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-
+static struct irqaction at91sam926x_pit_irq;
 /*
  * Clockevent device:  interrupts every 1/HZ (== pit_cycles * MCK/16)
  */
@@ -76,6 +76,8 @@ pit_clkevt_mode(enum clock_event_mode mo
 {
 	switch (mode) {
 	case CLOCK_EVT_MODE_PERIODIC:
+		/* Set up irq handler */
+		setup_irq(AT91_ID_SYS, &at91sam926x_pit_irq);
 		/* update clocksource counter */
 		pit_cnt += pit_cycle * PIT_PICNT(pit_read(AT91_PIT_PIVR));
 		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN
@@ -88,6 +90,7 @@ pit_clkevt_mode(enum clock_event_mode mo
 	case CLOCK_EVT_MODE_UNUSED:
 		/* disable irq, leaving the clocksource active */
 		pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN);
+		remove_irq(AT91_ID_SYS, &at91sam926x_pit_irq);
 		break;
 	case CLOCK_EVT_MODE_RESUME:
 		break;
Index: linux-3.4/drivers/clocksource/tcb_clksrc.c
===================================================================
--- linux-3.4.orig/drivers/clocksource/tcb_clksrc.c
+++ linux-3.4/drivers/clocksource/tcb_clksrc.c
@@ -23,8 +23,7 @@
  *     this 32 bit free-running counter. the second channel is not used.
  *
  *   - The third channel may be used to provide a 16-bit clockevent
- *     source, used in either periodic or oneshot mode.  This runs
- *     at 32 KiHZ, and can handle delays of up to two seconds.
+ *     source, used in either periodic or oneshot mode.
  *
  * A boot clocksource and clockevent source are also currently needed,
  * unless the relevant platforms (ARM/AT91, AVR32/AT32) are changed so
@@ -74,6 +73,7 @@ static struct clocksource clksrc = {
 struct tc_clkevt_device {
 	struct clock_event_device	clkevt;
 	struct clk			*clk;
+	u32				freq;
 	void __iomem			*regs;
 };
 
@@ -82,13 +82,6 @@ static struct tc_clkevt_device *to_tc_cl
 	return container_of(clkevt, struct tc_clkevt_device, clkevt);
 }
 
-/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
- * because using one of the divided clocks would usually mean the
- * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
- *
- * A divided clock could be good for high resolution timers, since
- * 30.5 usec resolution can seem "low".
- */
 static u32 timer_clock;
 
 static void tc_mode(enum clock_event_mode m, struct clock_event_device *d)
@@ -111,11 +104,12 @@ static void tc_mode(enum clock_event_mod
 	case CLOCK_EVT_MODE_PERIODIC:
 		clk_enable(tcd->clk);
 
-		/* slow clock, count up to RC, then irq and restart */
+		/* count up to RC, then irq and restart */
 		__raw_writel(timer_clock
 				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
 				regs + ATMEL_TC_REG(2, CMR));
-		__raw_writel((32768 + HZ/2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
+		__raw_writel((tcd->freq + HZ/2)/HZ,
+			     tcaddr + ATMEL_TC_REG(2, RC));
 
 		/* Enable clock and interrupts on RC compare */
 		__raw_writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
@@ -128,7 +122,7 @@ static void tc_mode(enum clock_event_mod
 	case CLOCK_EVT_MODE_ONESHOT:
 		clk_enable(tcd->clk);
 
-		/* slow clock, count up to RC, then irq and stop */
+		/* count up to RC, then irq and stop */
 		__raw_writel(timer_clock | ATMEL_TC_CPCSTOP
 				| ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
 				regs + ATMEL_TC_REG(2, CMR));
@@ -158,8 +152,12 @@ static struct tc_clkevt_device clkevt = 
 		.features	= CLOCK_EVT_FEAT_PERIODIC
 					| CLOCK_EVT_FEAT_ONESHOT,
 		.shift		= 32,
+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
 		/* Should be lower than at91rm9200's system timer */
 		.rating		= 125,
+#else
+		.rating		= 200,
+#endif
 		.set_next_event	= tc_next_event,
 		.set_mode	= tc_mode,
 	},
@@ -185,8 +183,9 @@ static struct irqaction tc_irqaction = {
 	.handler	= ch2_irq,
 };
 
-static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+static void __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
 {
+	unsigned divisor = atmel_tc_divisors[divisor_idx];
 	struct clk *t2_clk = tc->clk[2];
 	int irq = tc->irq[2];
 
@@ -194,11 +193,17 @@ static void __init setup_clkevents(struc
 	clkevt.clk = t2_clk;
 	tc_irqaction.dev_id = &clkevt;
 
-	timer_clock = clk32k_divisor_idx;
+	timer_clock = divisor_idx;
 
-	clkevt.clkevt.mult = div_sc(32768, NSEC_PER_SEC, clkevt.clkevt.shift);
-	clkevt.clkevt.max_delta_ns
-		= clockevent_delta2ns(0xffff, &clkevt.clkevt);
+	if (!divisor)
+		clkevt.freq = 32768;
+	else
+		clkevt.freq = clk_get_rate(t2_clk)/divisor;
+
+	clkevt.clkevt.mult = div_sc(clkevt.freq, NSEC_PER_SEC,
+				    clkevt.clkevt.shift);
+	clkevt.clkevt.max_delta_ns =
+		clockevent_delta2ns(0xffff, &clkevt.clkevt);
 	clkevt.clkevt.min_delta_ns = clockevent_delta2ns(1, &clkevt.clkevt) + 1;
 	clkevt.clkevt.cpumask = cpumask_of(0);
 
@@ -327,8 +332,11 @@ static int __init tcb_clksrc_init(void)
 	clocksource_register_hz(&clksrc, divided_rate);
 
 	/* channel 2:  periodic and oneshot timer support */
+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
 	setup_clkevents(tc, clk32k_divisor_idx);
-
+#else
+	setup_clkevents(tc, best_divisor_idx);
+#endif
 	return 0;
 }
 arch_initcall(tcb_clksrc_init);
Index: linux-3.4/drivers/misc/Kconfig
===================================================================
--- linux-3.4.orig/drivers/misc/Kconfig
+++ linux-3.4/drivers/misc/Kconfig
@@ -72,6 +72,7 @@ config AB8500_PWM
 config ATMEL_TCLIB
 	bool "Atmel AT32/AT91 Timer/Counter Library"
 	depends on (AVR32 || ARCH_AT91)
+	default y if PREEMPT_RT_FULL
 	help
 	  Select this if you want a library to allocate the Timer/Counter
 	  blocks found on many Atmel processors.  This facilitates using
@@ -87,8 +88,7 @@ config ATMEL_TCB_CLKSRC
 	  are combined to make a single 32-bit timer.
 
 	  When GENERIC_CLOCKEVENTS is defined, the third timer channel
-	  may be used as a clock event device supporting oneshot mode
-	  (delays of up to two seconds) based on the 32 KiHz clock.
+	  may be used as a clock event device supporting oneshot mode.
 
 config ATMEL_TCB_CLKSRC_BLOCK
 	int
@@ -102,6 +102,14 @@ config ATMEL_TCB_CLKSRC_BLOCK
 	  TC can be used for other purposes, such as PWM generation and
 	  interval timing.
 
+config ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
+	bool "TC Block use 32 KiHz clock"
+	depends on ATMEL_TCB_CLKSRC
+	default y if !PREEMPT_RT_FULL
+	help
+	  Select this to use 32 KiHz base clock rate as TC block clock
+	  source for clock events.
+
 config IBM_ASM
 	tristate "Device driver for IBM RSA service processor"
 	depends on X86 && PCI && INPUT && EXPERIMENTAL
@@ -123,6 +131,35 @@ config IBM_ASM
 	  for information on the specific driver level and support statement
 	  for your IBM server.
 
+config HWLAT_DETECTOR
+	tristate "Testing module to detect hardware-induced latencies"
+	depends on DEBUG_FS
+	depends on RING_BUFFER
+	default m
+	---help---
+	  A simple hardware latency detector. Use this module to detect
+	  large latencies introduced by the behavior of the underlying
+	  system firmware external to Linux. We do this using periodic
+	  use of stop_machine to grab all available CPUs and measure
+	  for unexplainable gaps in the CPU timestamp counter(s). By
+	  default, the module is not enabled until the "enable" file
+	  within the "hwlat_detector" debugfs directory is toggled.
+
+	  This module is often used to detect SMI (System Management
+	  Interrupts) on x86 systems, though is not x86 specific. To
+	  this end, we default to using a sample window of 1 second,
+	  during which we will sample for 0.5 seconds. If an SMI or
+	  similar event occurs during that time, it is recorded
+	  into an 8K samples global ring buffer until retreived.
+
+	  WARNING: This software should never be enabled (it can be built
+	  but should not be turned on after it is loaded) in a production
+	  environment where high latencies are a concern since the
+	  sampling mechanism actually introduces latencies for
+	  regular tasks while the CPU(s) are being held.
+
+	  If unsure, say N
+
 config PHANTOM
 	tristate "Sensable PHANToM (PCI)"
 	depends on PCI
Index: linux-3.4/drivers/net/ethernet/dec/tulip/tulip_core.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/dec/tulip/tulip_core.c
+++ linux-3.4/drivers/net/ethernet/dec/tulip/tulip_core.c
@@ -1946,6 +1946,7 @@ static void __devexit tulip_remove_one (
 	pci_iounmap(pdev, tp->base_addr);
 	free_netdev (dev);
 	pci_release_regions (pdev);
+	pci_disable_device (pdev);
 	pci_set_drvdata (pdev, NULL);
 
 	/* pci_power_off (pdev, -1); */
Index: linux-3.4/drivers/net/ethernet/realtek/8139too.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/realtek/8139too.c
+++ linux-3.4/drivers/net/ethernet/realtek/8139too.c
@@ -2240,7 +2240,7 @@ static irqreturn_t rtl8139_interrupt (in
  */
 static void rtl8139_poll_controller(struct net_device *dev)
 {
-	disable_irq(dev->irq);
+	disable_irq_nosync(dev->irq);
 	rtl8139_interrupt(dev->irq, dev);
 	enable_irq(dev->irq);
 }
Index: linux-3.4/drivers/net/ethernet/ibm/ehea/ehea_main.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/ibm/ehea/ehea_main.c
+++ linux-3.4/drivers/net/ethernet/ibm/ehea/ehea_main.c
@@ -1306,7 +1306,7 @@ static int ehea_reg_interrupts(struct ne
 			 "%s-queue%d", dev->name, i);
 		ret = ibmebus_request_irq(pr->eq->attr.ist1,
 					  ehea_recv_irq_handler,
-					  IRQF_DISABLED, pr->int_send_name,
+					  IRQF_NO_THREAD, pr->int_send_name,
 					  pr);
 		if (ret) {
 			netdev_err(dev, "failed registering irq for ehea_queue port_res_nr:%d, ist=%X\n",
Index: linux-3.4/drivers/net/ethernet/cadence/at91_ether.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/cadence/at91_ether.c
+++ linux-3.4/drivers/net/ethernet/cadence/at91_ether.c
@@ -201,7 +201,9 @@ static irqreturn_t at91ether_phy_interru
 	struct net_device *dev = (struct net_device *) dev_id;
 	struct at91_private *lp = netdev_priv(dev);
 	unsigned int phy;
+	unsigned long flags;
 
+	spin_lock_irqsave(&lp->lock, flags);
 	/*
 	 * This hander is triggered on both edges, but the PHY chips expect
 	 * level-triggering.  We therefore have to check if the PHY actually has
@@ -243,6 +245,7 @@ static irqreturn_t at91ether_phy_interru
 
 done:
 	disable_mdi();
+	spin_unlock_irqrestore(&lp->lock, flags);
 
 	return IRQ_HANDLED;
 }
@@ -399,9 +402,11 @@ static void at91ether_check_link(unsigne
 	struct net_device *dev = (struct net_device *) dev_id;
 	struct at91_private *lp = netdev_priv(dev);
 
+	spin_lock_irq(&lp->lock);
 	enable_mdi();
 	update_linkspeed(dev, 1);
 	disable_mdi();
+	spin_unlock_irq(&lp->lock);
 
 	mod_timer(&lp->check_timer, jiffies + LINK_POLL_INTERVAL);
 }
Index: linux-3.4/include/linux/uaccess.h
===================================================================
--- linux-3.4.orig/include/linux/uaccess.h
+++ linux-3.4/include/linux/uaccess.h
@@ -6,38 +6,37 @@
 
 /*
  * These routines enable/disable the pagefault handler in that
- * it will not take any locks and go straight to the fixup table.
- *
- * They have great resemblance to the preempt_disable/enable calls
- * and in fact they are identical; this is because currently there is
- * no other way to make the pagefault handlers do this. So we do
- * disable preemption but we don't necessarily care about that.
+ * it will not take any MM locks and go straight to the fixup table.
  */
-static inline void pagefault_disable(void)
+static inline void raw_pagefault_disable(void)
 {
 	inc_preempt_count();
-	/*
-	 * make sure to have issued the store before a pagefault
-	 * can hit.
-	 */
 	barrier();
 }
 
-static inline void pagefault_enable(void)
+static inline void raw_pagefault_enable(void)
 {
-	/*
-	 * make sure to issue those last loads/stores before enabling
-	 * the pagefault handler again.
-	 */
 	barrier();
 	dec_preempt_count();
-	/*
-	 * make sure we do..
-	 */
 	barrier();
 	preempt_check_resched();
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+static inline void pagefault_disable(void)
+{
+	raw_pagefault_disable();
+}
+
+static inline void pagefault_enable(void)
+{
+	raw_pagefault_enable();
+}
+#else
+extern void pagefault_disable(void);
+extern void pagefault_enable(void);
+#endif
+
 #ifndef ARCH_HAS_NOCACHE_UACCESS
 
 static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
@@ -77,9 +76,9 @@ static inline unsigned long __copy_from_
 		mm_segment_t old_fs = get_fs();		\
 							\
 		set_fs(KERNEL_DS);			\
-		pagefault_disable();			\
+		raw_pagefault_disable();		\
 		ret = __copy_from_user_inatomic(&(retval), (__force typeof(retval) __user *)(addr), sizeof(retval));		\
-		pagefault_enable();			\
+		raw_pagefault_enable();			\
 		set_fs(old_fs);				\
 		ret;					\
 	})
Index: linux-3.4/mm/memory.c
===================================================================
--- linux-3.4.orig/mm/memory.c
+++ linux-3.4/mm/memory.c
@@ -3467,6 +3467,32 @@ unlock:
 	return 0;
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+void pagefault_disable(void)
+{
+	migrate_disable();
+	current->pagefault_disabled++;
+	/*
+	 * make sure to have issued the store before a pagefault
+	 * can hit.
+	 */
+	barrier();
+}
+EXPORT_SYMBOL_GPL(pagefault_disable);
+
+void pagefault_enable(void)
+{
+	/*
+	 * make sure to issue those last loads/stores before enabling
+	 * the pagefault handler again.
+	 */
+	barrier();
+	current->pagefault_disabled--;
+	migrate_enable();
+}
+EXPORT_SYMBOL_GPL(pagefault_enable);
+#endif
+
 /*
  * By the time we get here, we already hold the mm semaphore
  */
@@ -4009,3 +4035,35 @@ void copy_user_huge_page(struct page *ds
 	}
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
+
+#if defined(CONFIG_PREEMPT_RT_FULL) && (USE_SPLIT_PTLOCKS > 0)
+/*
+ * Heinous hack, relies on the caller doing something like:
+ *
+ *   pte = alloc_pages(PGALLOC_GFP, 0);
+ *   if (pte)
+ *     pgtable_page_ctor(pte);
+ *   return pte;
+ *
+ * This ensures we release the page and return NULL when the
+ * lock allocation fails.
+ */
+struct page *pte_lock_init(struct page *page)
+{
+	page->ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
+	if (page->ptl) {
+		spin_lock_init(__pte_lockptr(page));
+	} else {
+		__free_page(page);
+		page = NULL;
+	}
+	return page;
+}
+
+void pte_lock_deinit(struct page *page)
+{
+	kfree(page->ptl);
+	page->mapping = NULL;
+}
+
+#endif
Index: linux-3.4/arch/alpha/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/alpha/mm/fault.c
+++ linux-3.4/arch/alpha/mm/fault.c
@@ -106,7 +106,7 @@ do_page_fault(unsigned long address, uns
 
 	/* If we're in an interrupt context, or have no user context,
 	   we must not take the fault.  */
-	if (!mm || in_atomic())
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
Index: linux-3.4/arch/arm/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/arm/mm/fault.c
+++ linux-3.4/arch/arm/mm/fault.c
@@ -277,7 +277,7 @@ do_page_fault(unsigned long addr, unsign
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	/*
Index: linux-3.4/arch/avr32/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/avr32/mm/fault.c
+++ linux-3.4/arch/avr32/mm/fault.c
@@ -81,7 +81,7 @@ asmlinkage void do_page_fault(unsigned l
 	 * If we're in an interrupt or have no user context, we must
 	 * not take the fault...
 	 */
-	if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM))
+	if (!mm || regs->sr & SYSREG_BIT(GM) || pagefault_disabled())
 		goto no_context;
 
 	local_irq_enable();
Index: linux-3.4/arch/cris/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/cris/mm/fault.c
+++ linux-3.4/arch/cris/mm/fault.c
@@ -112,7 +112,7 @@ do_page_fault(unsigned long address, str
 	 * user context, we must not take the fault.
 	 */
 
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/frv/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/frv/mm/fault.c
+++ linux-3.4/arch/frv/mm/fault.c
@@ -78,7 +78,7 @@ asmlinkage void do_page_fault(int datamm
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/ia64/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/ia64/mm/fault.c
+++ linux-3.4/arch/ia64/mm/fault.c
@@ -88,7 +88,7 @@ ia64_do_page_fault (unsigned long addres
 	/*
 	 * If we're in an interrupt or have no user context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP
Index: linux-3.4/arch/m32r/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/m32r/mm/fault.c
+++ linux-3.4/arch/m32r/mm/fault.c
@@ -114,7 +114,7 @@ asmlinkage void do_page_fault(struct pt_
 	 * If we're in an interrupt or have no user context or are running in an
 	 * atomic region then we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto bad_area_nosemaphore;
 
 	/* When running in the kernel we expect faults to occur only to
Index: linux-3.4/arch/m68k/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/m68k/mm/fault.c
+++ linux-3.4/arch/m68k/mm/fault.c
@@ -84,7 +84,7 @@ int do_page_fault(struct pt_regs *regs, 
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/microblaze/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/microblaze/mm/fault.c
+++ linux-3.4/arch/microblaze/mm/fault.c
@@ -106,7 +106,7 @@ void do_page_fault(struct pt_regs *regs,
 	if ((error_code & 0x13) == 0x13 || (error_code & 0x11) == 0x11)
 		is_write = 0;
 
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(!mm || pagefault_disabled())) {
 		if (kernel_mode(regs))
 			goto bad_area_nosemaphore;
 
Index: linux-3.4/arch/mips/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/mips/mm/fault.c
+++ linux-3.4/arch/mips/mm/fault.c
@@ -89,7 +89,7 @@ asmlinkage void __kprobes do_page_fault(
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto bad_area_nosemaphore;
 
 retry:
Index: linux-3.4/arch/mn10300/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/mn10300/mm/fault.c
+++ linux-3.4/arch/mn10300/mm/fault.c
@@ -167,7 +167,7 @@ asmlinkage void do_page_fault(struct pt_
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/parisc/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/parisc/mm/fault.c
+++ linux-3.4/arch/parisc/mm/fault.c
@@ -176,7 +176,7 @@ void do_page_fault(struct pt_regs *regs,
 	unsigned long acc_type;
 	int fault;
 
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/powerpc/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/powerpc/mm/fault.c
+++ linux-3.4/arch/powerpc/mm/fault.c
@@ -261,7 +261,7 @@ int __kprobes do_page_fault(struct pt_re
 	if (!arch_irq_disabled_regs(regs))
 		local_irq_enable();
 
-	if (in_atomic() || mm == NULL) {
+	if (!mm || pagefault_disabled()) {
 		if (!user_mode(regs))
 			return SIGSEGV;
 		/* in_atomic() in user mode is really bad,
Index: linux-3.4/arch/s390/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/s390/mm/fault.c
+++ linux-3.4/arch/s390/mm/fault.c
@@ -283,7 +283,8 @@ static inline int do_exception(struct pt
 	 * user context.
 	 */
 	fault = VM_FAULT_BADCONTEXT;
-	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) ||
+		     !mm || pagefault_disabled()))
 		goto out;
 
 	address = trans_exc_code & __FAIL_ADDR_MASK;
@@ -415,7 +416,8 @@ void __kprobes do_asce_exception(struct 
 	unsigned long trans_exc_code;
 
 	trans_exc_code = regs->int_parm_long;
-	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm ||
+		     pagefault_disabled()))
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/score/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/score/mm/fault.c
+++ linux-3.4/arch/score/mm/fault.c
@@ -72,7 +72,7 @@ asmlinkage void do_page_fault(struct pt_
 	* If we're in an interrupt or have no user
 	* context, we must not take the fault..
 	*/
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto bad_area_nosemaphore;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/sh/mm/fault_32.c
===================================================================
--- linux-3.4.orig/arch/sh/mm/fault_32.c
+++ linux-3.4/arch/sh/mm/fault_32.c
@@ -166,7 +166,7 @@ asmlinkage void __kprobes do_page_fault(
 	 * If we're in an interrupt, have no user context or are running
 	 * in an atomic region then we must not take the fault:
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/sparc/mm/fault_32.c
===================================================================
--- linux-3.4.orig/arch/sparc/mm/fault_32.c
+++ linux-3.4/arch/sparc/mm/fault_32.c
@@ -248,8 +248,8 @@ asmlinkage void do_sparc_fault(struct pt
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-        if (in_atomic() || !mm)
-                goto no_context;
+	if (!mm || pagefault_disabled())
+		goto no_context;
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
Index: linux-3.4/arch/sparc/mm/fault_64.c
===================================================================
--- linux-3.4.orig/arch/sparc/mm/fault_64.c
+++ linux-3.4/arch/sparc/mm/fault_64.c
@@ -323,7 +323,7 @@ asmlinkage void __kprobes do_sparc64_fau
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (!mm || pagefault_disabled())
 		goto intr_or_no_mm;
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
Index: linux-3.4/arch/tile/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/tile/mm/fault.c
+++ linux-3.4/arch/tile/mm/fault.c
@@ -355,7 +355,7 @@ static int handle_page_fault(struct pt_r
 	 * If we're in an interrupt, have no user context or are running in an
 	 * atomic region then we must not take the fault.
 	 */
-	if (in_atomic() || !mm) {
+	if (!mm || pagefault_disabled()) {
 		vma = NULL;  /* happy compiler */
 		goto bad_area_nosemaphore;
 	}
Index: linux-3.4/arch/um/kernel/trap.c
===================================================================
--- linux-3.4.orig/arch/um/kernel/trap.c
+++ linux-3.4/arch/um/kernel/trap.c
@@ -37,7 +37,7 @@ int handle_page_fault(unsigned long addr
 	 * If the fault was during atomic operation, don't take the fault, just
 	 * fail.
 	 */
-	if (in_atomic())
+	if (!mm || pagefault_disabled())
 		goto out_nosemaphore;
 
 	down_read(&mm->mmap_sem);
Index: linux-3.4/arch/x86/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/x86/mm/fault.c
+++ linux-3.4/arch/x86/mm/fault.c
@@ -1094,7 +1094,7 @@ do_page_fault(struct pt_regs *regs, unsi
 	 * If we're in an interrupt, have no user context or are running
 	 * in an atomic region then we must not take the fault:
 	 */
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(!mm || pagefault_disabled())) {
 		bad_area_nosemaphore(regs, error_code, address);
 		return;
 	}
Index: linux-3.4/arch/xtensa/mm/fault.c
===================================================================
--- linux-3.4.orig/arch/xtensa/mm/fault.c
+++ linux-3.4/arch/xtensa/mm/fault.c
@@ -56,7 +56,7 @@ void do_page_fault(struct pt_regs *regs)
 	/* If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm) {
+	if (!mm || pagefault_disabled()) {
 		bad_page_fault(regs, address, SIGSEGV);
 		return;
 	}
Index: linux-3.4/mm/filemap.c
===================================================================
--- linux-3.4.orig/mm/filemap.c
+++ linux-3.4/mm/filemap.c
@@ -2036,7 +2036,7 @@ size_t iov_iter_copy_from_user_atomic(st
 	char *kaddr;
 	size_t copied;
 
-	BUG_ON(!in_atomic());
+	BUG_ON(!pagefault_disabled());
 	kaddr = kmap_atomic(page);
 	if (likely(i->nr_segs == 1)) {
 		int left;
Index: linux-3.4/arch/x86/mm/highmem_32.c
===================================================================
--- linux-3.4.orig/arch/x86/mm/highmem_32.c
+++ linux-3.4/arch/x86/mm/highmem_32.c
@@ -43,7 +43,7 @@ void *kmap_atomic_prot(struct page *page
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-	BUG_ON(!pte_none(*(kmap_pte-idx)));
+	WARN_ON(!pte_none(*(kmap_pte-idx)));
 	set_pte(kmap_pte-idx, mk_pte(page, prot));
 	arch_flush_lazy_mmu_mode();
 
Index: linux-3.4/include/linux/kernel.h
===================================================================
--- linux-3.4.orig/include/linux/kernel.h
+++ linux-3.4/include/linux/kernel.h
@@ -374,7 +374,7 @@ extern enum system_states {
 	SYSTEM_HALT,
 	SYSTEM_POWER_OFF,
 	SYSTEM_RESTART,
-	SYSTEM_SUSPEND_DISK,
+	SYSTEM_SUSPEND,
 } system_state;
 
 #define TAINT_PROPRIETARY_MODULE	0
Index: linux-3.4/kernel/power/hibernate.c
===================================================================
--- linux-3.4.orig/kernel/power/hibernate.c
+++ linux-3.4/kernel/power/hibernate.c
@@ -270,6 +270,8 @@ static int create_image(int platform_mod
 
 	local_irq_disable();
 
+	system_state = SYSTEM_SUSPEND;
+
 	error = syscore_suspend();
 	if (error) {
 		printk(KERN_ERR "PM: Some system devices failed to power down, "
@@ -297,6 +299,7 @@ static int create_image(int platform_mod
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -420,6 +423,7 @@ static int resume_target_kernel(bool pla
 		goto Enable_cpus;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 
 	error = syscore_suspend();
 	if (error)
@@ -453,6 +457,7 @@ static int resume_target_kernel(bool pla
 	syscore_resume();
 
  Enable_irqs:
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 
  Enable_cpus:
@@ -532,6 +537,7 @@ int hibernation_platform_enter(void)
 		goto Platform_finish;
 
 	local_irq_disable();
+	system_state = SYSTEM_SUSPEND;
 	syscore_suspend();
 	if (pm_wakeup_pending()) {
 		error = -EAGAIN;
@@ -544,6 +550,7 @@ int hibernation_platform_enter(void)
 
  Power_up:
 	syscore_resume();
+	system_state = SYSTEM_RUNNING;
 	local_irq_enable();
 	enable_nonboot_cpus();
 
Index: linux-3.4/kernel/power/suspend.c
===================================================================
--- linux-3.4.orig/kernel/power/suspend.c
+++ linux-3.4/kernel/power/suspend.c
@@ -164,6 +164,8 @@ static int suspend_enter(suspend_state_t
 	arch_suspend_disable_irqs();
 	BUG_ON(!irqs_disabled());
 
+	system_state = SYSTEM_SUSPEND;
+
 	error = syscore_suspend();
 	if (!error) {
 		*wakeup = pm_wakeup_pending();
@@ -174,6 +176,8 @@ static int suspend_enter(suspend_state_t
 		syscore_resume();
 	}
 
+	system_state = SYSTEM_RUNNING;
+
 	arch_suspend_enable_irqs();
 	BUG_ON(irqs_disabled());
 
Index: linux-3.4/drivers/of/base.c
===================================================================
--- linux-3.4.orig/drivers/of/base.c
+++ linux-3.4/drivers/of/base.c
@@ -54,7 +54,7 @@ static DEFINE_MUTEX(of_aliases_mutex);
 /* use when traversing tree through the allnext, child, sibling,
  * or parent members of struct device_node.
  */
-DEFINE_RWLOCK(devtree_lock);
+DEFINE_RAW_SPINLOCK(devtree_lock);
 
 int of_n_addr_cells(struct device_node *np)
 {
@@ -163,16 +163,14 @@ void of_node_put(struct device_node *nod
 EXPORT_SYMBOL(of_node_put);
 #endif /* CONFIG_OF_DYNAMIC */
 
-struct property *of_find_property(const struct device_node *np,
-				  const char *name,
-				  int *lenp)
+static struct property *__of_find_property(const struct device_node *np,
+					   const char *name, int *lenp)
 {
 	struct property *pp;
 
 	if (!np)
 		return NULL;
 
-	read_lock(&devtree_lock);
 	for (pp = np->properties; pp != 0; pp = pp->next) {
 		if (of_prop_cmp(pp->name, name) == 0) {
 			if (lenp != 0)
@@ -180,7 +178,20 @@ struct property *of_find_property(const 
 			break;
 		}
 	}
-	read_unlock(&devtree_lock);
+
+	return pp;
+}
+
+struct property *of_find_property(const struct device_node *np,
+				  const char *name,
+				  int *lenp)
+{
+	struct property *pp;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	pp = __of_find_property(np, name, lenp);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
 	return pp;
 }
@@ -198,13 +209,13 @@ struct device_node *of_find_all_nodes(st
 {
 	struct device_node *np;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock(&devtree_lock);
 	np = prev ? prev->allnext : allnodes;
 	for (; np != NULL; np = np->allnext)
 		if (of_node_get(np))
 			break;
 	of_node_put(prev);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock(&devtree_lock);
 	return np;
 }
 EXPORT_SYMBOL(of_find_all_nodes);
@@ -213,8 +224,20 @@ EXPORT_SYMBOL(of_find_all_nodes);
  * Find a property with a given name for a given node
  * and return the value.
  */
+static const void *__of_get_property(const struct device_node *np,
+				     const char *name, int *lenp)
+{
+	struct property *pp = __of_find_property(np, name, lenp);
+
+	return pp ? pp->value : NULL;
+}
+
+/*
+ * Find a property with a given name for a given node
+ * and return the value.
+ */
 const void *of_get_property(const struct device_node *np, const char *name,
-			 int *lenp)
+			    int *lenp)
 {
 	struct property *pp = of_find_property(np, name, lenp);
 
@@ -225,13 +248,13 @@ EXPORT_SYMBOL(of_get_property);
 /** Checks if the given "compat" string matches one of the strings in
  * the device's "compatible" property
  */
-int of_device_is_compatible(const struct device_node *device,
-		const char *compat)
+static int __of_device_is_compatible(const struct device_node *device,
+				     const char *compat)
 {
 	const char* cp;
-	int cplen, l;
+	int uninitialized_var(cplen), l;
 
-	cp = of_get_property(device, "compatible", &cplen);
+	cp = __of_get_property(device, "compatible", &cplen);
 	if (cp == NULL)
 		return 0;
 	while (cplen > 0) {
@@ -244,6 +267,21 @@ int of_device_is_compatible(const struct
 
 	return 0;
 }
+
+/** Checks if the given "compat" string matches one of the strings in
+ * the device's "compatible" property
+ */
+int of_device_is_compatible(const struct device_node *device,
+		const char *compat)
+{
+	unsigned long flags;
+	int res;
+
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	res = __of_device_is_compatible(device, compat);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	return res;
+}
 EXPORT_SYMBOL(of_device_is_compatible);
 
 /**
@@ -303,13 +341,14 @@ EXPORT_SYMBOL(of_device_is_available);
 struct device_node *of_get_parent(const struct device_node *node)
 {
 	struct device_node *np;
+	unsigned long flags;
 
 	if (!node)
 		return NULL;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = of_node_get(node->parent);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_get_parent);
@@ -328,14 +367,15 @@ EXPORT_SYMBOL(of_get_parent);
 struct device_node *of_get_next_parent(struct device_node *node)
 {
 	struct device_node *parent;
+	unsigned long flags;
 
 	if (!node)
 		return NULL;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	parent = of_node_get(node->parent);
 	of_node_put(node);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return parent;
 }
 
@@ -351,14 +391,15 @@ struct device_node *of_get_next_child(co
 	struct device_node *prev)
 {
 	struct device_node *next;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	next = prev ? prev->sibling : node->child;
 	for (; next; next = next->sibling)
 		if (of_node_get(next))
 			break;
 	of_node_put(prev);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return next;
 }
 EXPORT_SYMBOL(of_get_next_child);
@@ -373,14 +414,15 @@ EXPORT_SYMBOL(of_get_next_child);
 struct device_node *of_find_node_by_path(const char *path)
 {
 	struct device_node *np = allnodes;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	for (; np; np = np->allnext) {
 		if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
 		    && of_node_get(np))
 			break;
 	}
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_by_path);
@@ -400,15 +442,16 @@ struct device_node *of_find_node_by_name
 	const char *name)
 {
 	struct device_node *np;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = from ? from->allnext : allnodes;
 	for (; np; np = np->allnext)
 		if (np->name && (of_node_cmp(np->name, name) == 0)
 		    && of_node_get(np))
 			break;
 	of_node_put(from);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_by_name);
@@ -429,15 +472,16 @@ struct device_node *of_find_node_by_type
 	const char *type)
 {
 	struct device_node *np;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = from ? from->allnext : allnodes;
 	for (; np; np = np->allnext)
 		if (np->type && (of_node_cmp(np->type, type) == 0)
 		    && of_node_get(np))
 			break;
 	of_node_put(from);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_by_type);
@@ -460,18 +504,20 @@ struct device_node *of_find_compatible_n
 	const char *type, const char *compatible)
 {
 	struct device_node *np;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = from ? from->allnext : allnodes;
 	for (; np; np = np->allnext) {
 		if (type
 		    && !(np->type && (of_node_cmp(np->type, type) == 0)))
 			continue;
-		if (of_device_is_compatible(np, compatible) && of_node_get(np))
+		if (__of_device_is_compatible(np, compatible) &&
+		    of_node_get(np))
 			break;
 	}
 	of_node_put(from);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_compatible_node);
@@ -493,8 +539,9 @@ struct device_node *of_find_node_with_pr
 {
 	struct device_node *np;
 	struct property *pp;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = from ? from->allnext : allnodes;
 	for (; np; np = np->allnext) {
 		for (pp = np->properties; pp != 0; pp = pp->next) {
@@ -506,20 +553,14 @@ struct device_node *of_find_node_with_pr
 	}
 out:
 	of_node_put(from);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_with_property);
 
-/**
- * of_match_node - Tell if an device_node has a matching of_match structure
- *	@matches:	array of of device match structures to search in
- *	@node:		the of device structure to match against
- *
- *	Low level utility function used by device matching.
- */
-const struct of_device_id *of_match_node(const struct of_device_id *matches,
-					 const struct device_node *node)
+static
+const struct of_device_id *__of_match_node(const struct of_device_id *matches,
+					   const struct device_node *node)
 {
 	if (!matches)
 		return NULL;
@@ -533,14 +574,33 @@ const struct of_device_id *of_match_node
 			match &= node->type
 				&& !strcmp(matches->type, node->type);
 		if (matches->compatible[0])
-			match &= of_device_is_compatible(node,
-						matches->compatible);
+			match &= __of_device_is_compatible(node,
+							   matches->compatible);
 		if (match)
 			return matches;
 		matches++;
 	}
 	return NULL;
 }
+
+/**
+ * of_match_node - Tell if an device_node has a matching of_match structure
+ *	@matches:	array of of device match structures to search in
+ *	@node:		the of device structure to match against
+ *
+ *	Low level utility function used by device matching.
+ */
+const struct of_device_id *of_match_node(const struct of_device_id *matches,
+					 const struct device_node *node)
+{
+	const struct of_device_id *match;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&devtree_lock, flags);
+	match = __of_match_node(matches, node);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	return match;
+}
 EXPORT_SYMBOL(of_match_node);
 
 /**
@@ -559,15 +619,16 @@ struct device_node *of_find_matching_nod
 					  const struct of_device_id *matches)
 {
 	struct device_node *np;
+	unsigned long flags;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np = from ? from->allnext : allnodes;
 	for (; np; np = np->allnext) {
-		if (of_match_node(matches, np) && of_node_get(np))
+		if (__of_match_node(matches, np) && of_node_get(np))
 			break;
 	}
 	of_node_put(from);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 	return np;
 }
 EXPORT_SYMBOL(of_find_matching_node);
@@ -610,12 +671,12 @@ struct device_node *of_find_node_by_phan
 {
 	struct device_node *np;
 
-	read_lock(&devtree_lock);
+	raw_spin_lock(&devtree_lock);
 	for (np = allnodes; np; np = np->allnext)
 		if (np->phandle == handle)
 			break;
 	of_node_get(np);
-	read_unlock(&devtree_lock);
+	raw_spin_unlock(&devtree_lock);
 	return np;
 }
 EXPORT_SYMBOL(of_find_node_by_phandle);
@@ -987,18 +1048,18 @@ int prom_add_property(struct device_node
 	unsigned long flags;
 
 	prop->next = NULL;
-	write_lock_irqsave(&devtree_lock, flags);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	next = &np->properties;
 	while (*next) {
 		if (strcmp(prop->name, (*next)->name) == 0) {
 			/* duplicate ! don't insert it */
-			write_unlock_irqrestore(&devtree_lock, flags);
+			raw_spin_unlock_irqrestore(&devtree_lock, flags);
 			return -1;
 		}
 		next = &(*next)->next;
 	}
 	*next = prop;
-	write_unlock_irqrestore(&devtree_lock, flags);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
 #ifdef CONFIG_PROC_DEVICETREE
 	/* try to add to proc as well if it was initialized */
@@ -1023,7 +1084,7 @@ int prom_remove_property(struct device_n
 	unsigned long flags;
 	int found = 0;
 
-	write_lock_irqsave(&devtree_lock, flags);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	next = &np->properties;
 	while (*next) {
 		if (*next == prop) {
@@ -1036,7 +1097,7 @@ int prom_remove_property(struct device_n
 		}
 		next = &(*next)->next;
 	}
-	write_unlock_irqrestore(&devtree_lock, flags);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
 	if (!found)
 		return -ENODEV;
@@ -1066,7 +1127,7 @@ int prom_update_property(struct device_n
 	unsigned long flags;
 	int found = 0;
 
-	write_lock_irqsave(&devtree_lock, flags);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	next = &np->properties;
 	while (*next) {
 		if (*next == oldprop) {
@@ -1080,7 +1141,7 @@ int prom_update_property(struct device_n
 		}
 		next = &(*next)->next;
 	}
-	write_unlock_irqrestore(&devtree_lock, flags);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 
 	if (!found)
 		return -ENODEV;
@@ -1110,12 +1171,12 @@ void of_attach_node(struct device_node *
 {
 	unsigned long flags;
 
-	write_lock_irqsave(&devtree_lock, flags);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 	np->sibling = np->parent->child;
 	np->allnext = allnodes;
 	np->parent->child = np;
 	allnodes = np;
-	write_unlock_irqrestore(&devtree_lock, flags);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 }
 
 /**
@@ -1129,7 +1190,7 @@ void of_detach_node(struct device_node *
 	struct device_node *parent;
 	unsigned long flags;
 
-	write_lock_irqsave(&devtree_lock, flags);
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 
 	parent = np->parent;
 	if (!parent)
@@ -1160,7 +1221,7 @@ void of_detach_node(struct device_node *
 	of_node_set_flag(np, OF_DETACHED);
 
 out_unlock:
-	write_unlock_irqrestore(&devtree_lock, flags);
+	raw_spin_unlock_irqrestore(&devtree_lock, flags);
 }
 #endif /* defined(CONFIG_OF_DYNAMIC) */
 
Index: linux-3.4/arch/sparc/kernel/prom_common.c
===================================================================
--- linux-3.4.orig/arch/sparc/kernel/prom_common.c
+++ linux-3.4/arch/sparc/kernel/prom_common.c
@@ -65,7 +65,7 @@ int of_set_property(struct device_node *
 	err = -ENODEV;
 
 	mutex_lock(&of_set_property_mutex);
-	write_lock(&devtree_lock);
+	raw_spin_lock(&devtree_lock);
 	prevp = &dp->properties;
 	while (*prevp) {
 		struct property *prop = *prevp;
@@ -92,7 +92,7 @@ int of_set_property(struct device_node *
 		}
 		prevp = &(*prevp)->next;
 	}
-	write_unlock(&devtree_lock);
+	raw_spin_unlock(&devtree_lock);
 	mutex_unlock(&of_set_property_mutex);
 
 	/* XXX Upate procfs if necessary... */
Index: linux-3.4/include/linux/of.h
===================================================================
--- linux-3.4.orig/include/linux/of.h
+++ linux-3.4/include/linux/of.h
@@ -90,7 +90,7 @@ static inline void of_node_put(struct de
 extern struct device_node *allnodes;
 extern struct device_node *of_chosen;
 extern struct device_node *of_aliases;
-extern rwlock_t devtree_lock;
+extern raw_spinlock_t devtree_lock;
 
 static inline bool of_have_populated_dt(void)
 {
Index: linux-3.4/include/linux/list.h
===================================================================
--- linux-3.4.orig/include/linux/list.h
+++ linux-3.4/include/linux/list.h
@@ -362,6 +362,17 @@ static inline void list_splice_tail_init
 	list_entry((ptr)->next, type, member)
 
 /**
+ * list_last_entry - get the last element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_struct within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_last_entry(ptr, type, member) \
+	list_entry((ptr)->prev, type, member)
+
+/**
  * list_for_each	-	iterate over a list
  * @pos:	the &struct list_head to use as a loop cursor.
  * @head:	the head for your list.
Index: linux-3.4/mm/page_alloc.c
===================================================================
--- linux-3.4.orig/mm/page_alloc.c
+++ linux-3.4/mm/page_alloc.c
@@ -57,6 +57,7 @@
 #include <linux/ftrace_event.h>
 #include <linux/memcontrol.h>
 #include <linux/prefetch.h>
+#include <linux/locallock.h>
 #include <linux/page-debug-flags.h>
 
 #include <asm/tlbflush.h>
@@ -216,6 +217,18 @@ EXPORT_SYMBOL(nr_node_ids);
 EXPORT_SYMBOL(nr_online_nodes);
 #endif
 
+static DEFINE_LOCAL_IRQ_LOCK(pa_lock);
+
+#ifdef CONFIG_PREEMPT_RT_BASE
+# define cpu_lock_irqsave(cpu, flags)		\
+	spin_lock_irqsave(&per_cpu(pa_lock, cpu).lock, flags)
+# define cpu_unlock_irqrestore(cpu, flags)		\
+	spin_unlock_irqrestore(&per_cpu(pa_lock, cpu).lock, flags)
+#else
+# define cpu_lock_irqsave(cpu, flags)		local_irq_save(flags)
+# define cpu_unlock_irqrestore(cpu, flags)	local_irq_restore(flags)
+#endif
+
 int page_group_by_mobility_disabled __read_mostly;
 
 static void set_pageblock_migratetype(struct page *page, int migratetype)
@@ -619,7 +632,7 @@ static inline int free_pages_check(struc
 }
 
 /*
- * Frees a number of pages from the PCP lists
+ * Frees a number of pages which have been collected from the pcp lists.
  * Assumes all pages on list are in same zone, and of same order.
  * count is the number of pages to free.
  *
@@ -630,16 +643,42 @@ static inline int free_pages_check(struc
  * pinned" detection logic.
  */
 static void free_pcppages_bulk(struct zone *zone, int count,
-					struct per_cpu_pages *pcp)
+			       struct list_head *list)
 {
-	int migratetype = 0;
-	int batch_free = 0;
 	int to_free = count;
+	unsigned long flags;
 
-	spin_lock(&zone->lock);
+	spin_lock_irqsave(&zone->lock, flags);
 	zone->all_unreclaimable = 0;
 	zone->pages_scanned = 0;
 
+	while (!list_empty(list)) {
+		struct page *page = list_first_entry(list, struct page, lru);
+
+		/* must delete as __free_one_page list manipulates */
+		list_del(&page->lru);
+		/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
+		__free_one_page(page, zone, 0, page_private(page));
+		trace_mm_page_pcpu_drain(page, 0, page_private(page));
+		to_free--;
+	}
+	WARN_ON(to_free != 0);
+	__mod_zone_page_state(zone, NR_FREE_PAGES, count);
+	spin_unlock_irqrestore(&zone->lock, flags);
+}
+
+/*
+ * Moves a number of pages from the PCP lists to free list which
+ * is freed outside of the locked region.
+ *
+ * Assumes all pages on list are in same zone, and of same order.
+ * count is the number of pages to free.
+ */
+static void isolate_pcp_pages(int to_free, struct per_cpu_pages *src,
+			      struct list_head *dst)
+{
+	int migratetype = 0, batch_free = 0;
+
 	while (to_free) {
 		struct page *page;
 		struct list_head *list;
@@ -655,7 +694,7 @@ static void free_pcppages_bulk(struct zo
 			batch_free++;
 			if (++migratetype == MIGRATE_PCPTYPES)
 				migratetype = 0;
-			list = &pcp->lists[migratetype];
+			list = &src->lists[migratetype];
 		} while (list_empty(list));
 
 		/* This is the only non-empty list. Free them all. */
@@ -663,28 +702,25 @@ static void free_pcppages_bulk(struct zo
 			batch_free = to_free;
 
 		do {
-			page = list_entry(list->prev, struct page, lru);
-			/* must delete as __free_one_page list manipulates */
+			page = list_last_entry(list, struct page, lru);
 			list_del(&page->lru);
-			/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
-			__free_one_page(page, zone, 0, page_private(page));
-			trace_mm_page_pcpu_drain(page, 0, page_private(page));
+			list_add(&page->lru, dst);
 		} while (--to_free && --batch_free && !list_empty(list));
 	}
-	__mod_zone_page_state(zone, NR_FREE_PAGES, count);
-	spin_unlock(&zone->lock);
 }
 
 static void free_one_page(struct zone *zone, struct page *page, int order,
 				int migratetype)
 {
-	spin_lock(&zone->lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&zone->lock, flags);
 	zone->all_unreclaimable = 0;
 	zone->pages_scanned = 0;
 
 	__free_one_page(page, zone, order, migratetype);
 	__mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
-	spin_unlock(&zone->lock);
+	spin_unlock_irqrestore(&zone->lock, flags);
 }
 
 static bool free_pages_prepare(struct page *page, unsigned int order)
@@ -721,13 +757,13 @@ static void __free_pages_ok(struct page 
 	if (!free_pages_prepare(page, order))
 		return;
 
-	local_irq_save(flags);
+	local_lock_irqsave(pa_lock, flags);
 	if (unlikely(wasMlocked))
 		free_page_mlock(page);
 	__count_vm_events(PGFREE, 1 << order);
 	free_one_page(page_zone(page), page, order,
 					get_pageblock_migratetype(page));
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pa_lock, flags);
 }
 
 void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
@@ -1111,16 +1147,18 @@ static int rmqueue_bulk(struct zone *zon
 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 {
 	unsigned long flags;
+	LIST_HEAD(dst);
 	int to_drain;
 
-	local_irq_save(flags);
+	local_lock_irqsave(pa_lock, flags);
 	if (pcp->count >= pcp->batch)
 		to_drain = pcp->batch;
 	else
 		to_drain = pcp->count;
-	free_pcppages_bulk(zone, to_drain, pcp);
+	isolate_pcp_pages(to_drain, pcp, &dst);
 	pcp->count -= to_drain;
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pa_lock, flags);
+	free_pcppages_bulk(zone, to_drain, &dst);
 }
 #endif
 
@@ -1139,16 +1177,21 @@ static void drain_pages(unsigned int cpu
 	for_each_populated_zone(zone) {
 		struct per_cpu_pageset *pset;
 		struct per_cpu_pages *pcp;
+		LIST_HEAD(dst);
+		int count;
 
-		local_irq_save(flags);
+		cpu_lock_irqsave(cpu, flags);
 		pset = per_cpu_ptr(zone->pageset, cpu);
 
 		pcp = &pset->pcp;
-		if (pcp->count) {
-			free_pcppages_bulk(zone, pcp->count, pcp);
+		count = pcp->count;
+		if (count) {
+			isolate_pcp_pages(count, pcp, &dst);
 			pcp->count = 0;
 		}
-		local_irq_restore(flags);
+		cpu_unlock_irqrestore(cpu, flags);
+		if (count)
+			free_pcppages_bulk(zone, count, &dst);
 	}
 }
 
@@ -1201,7 +1244,12 @@ void drain_all_pages(void)
 		else
 			cpumask_clear_cpu(cpu, &cpus_with_pcps);
 	}
+#ifndef CONFIG_PREEMPT_RT_BASE
 	on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1);
+#else
+	for_each_cpu(cpu, &cpus_with_pcps)
+		drain_pages(cpu);
+#endif
 }
 
 #ifdef CONFIG_HIBERNATION
@@ -1257,7 +1305,7 @@ void free_hot_cold_page(struct page *pag
 
 	migratetype = get_pageblock_migratetype(page);
 	set_page_private(page, migratetype);
-	local_irq_save(flags);
+	local_lock_irqsave(pa_lock, flags);
 	if (unlikely(wasMlocked))
 		free_page_mlock(page);
 	__count_vm_event(PGFREE);
@@ -1284,12 +1332,19 @@ void free_hot_cold_page(struct page *pag
 		list_add(&page->lru, &pcp->lists[migratetype]);
 	pcp->count++;
 	if (pcp->count >= pcp->high) {
-		free_pcppages_bulk(zone, pcp->batch, pcp);
+		LIST_HEAD(dst);
+		int count;
+
+		isolate_pcp_pages(pcp->batch, pcp, &dst);
 		pcp->count -= pcp->batch;
+		count = pcp->batch;
+		local_unlock_irqrestore(pa_lock, flags);
+		free_pcppages_bulk(zone, count, &dst);
+		return;
 	}
 
 out:
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pa_lock, flags);
 }
 
 /*
@@ -1397,7 +1452,7 @@ again:
 		struct per_cpu_pages *pcp;
 		struct list_head *list;
 
-		local_irq_save(flags);
+		local_lock_irqsave(pa_lock, flags);
 		pcp = &this_cpu_ptr(zone->pageset)->pcp;
 		list = &pcp->lists[migratetype];
 		if (list_empty(list)) {
@@ -1429,17 +1484,19 @@ again:
 			 */
 			WARN_ON_ONCE(order > 1);
 		}
-		spin_lock_irqsave(&zone->lock, flags);
+		local_spin_lock_irqsave(pa_lock, &zone->lock, flags);
 		page = __rmqueue(zone, order, migratetype);
-		spin_unlock(&zone->lock);
-		if (!page)
+		if (!page) {
+			spin_unlock(&zone->lock);
 			goto failed;
+		}
 		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
+		spin_unlock(&zone->lock);
 	}
 
 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
 	zone_statistics(preferred_zone, zone, gfp_flags);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pa_lock, flags);
 
 	VM_BUG_ON(bad_range(zone, page));
 	if (prep_new_page(page, order, gfp_flags))
@@ -1447,7 +1504,7 @@ again:
 	return page;
 
 failed:
-	local_irq_restore(flags);
+	local_unlock_irqrestore(pa_lock, flags);
 	return NULL;
 }
 
@@ -2038,8 +2095,8 @@ __alloc_pages_direct_compact(gfp_t gfp_m
 	if (*did_some_progress != COMPACT_SKIPPED) {
 
 		/* Page migration frees to the PCP lists but we want merging */
-		drain_pages(get_cpu());
-		put_cpu();
+		drain_pages(get_cpu_light());
+		put_cpu_light();
 
 		page = get_page_from_freelist(gfp_mask, nodemask,
 				order, zonelist, high_zoneidx,
@@ -3854,14 +3911,16 @@ static int __zone_pcp_update(void *data)
 	for_each_possible_cpu(cpu) {
 		struct per_cpu_pageset *pset;
 		struct per_cpu_pages *pcp;
+		LIST_HEAD(dst);
 
 		pset = per_cpu_ptr(zone->pageset, cpu);
 		pcp = &pset->pcp;
 
-		local_irq_save(flags);
-		free_pcppages_bulk(zone, pcp->count, pcp);
+		cpu_lock_irqsave(cpu, flags);
+		isolate_pcp_pages(pcp->count, pcp, &dst);
+		free_pcppages_bulk(zone, pcp->count, &dst);
 		setup_pageset(pset, batch);
-		local_irq_restore(flags);
+		cpu_unlock_irqrestore(cpu, flags);
 	}
 	return 0;
 }
@@ -4892,6 +4951,7 @@ static int page_alloc_cpu_notify(struct 
 void __init page_alloc_init(void)
 {
 	hotcpu_notifier(page_alloc_cpu_notify, 0);
+	local_irq_lock_init(pa_lock);
 }
 
 /*
Index: linux-3.4/include/linux/pid.h
===================================================================
--- linux-3.4.orig/include/linux/pid.h
+++ linux-3.4/include/linux/pid.h
@@ -2,6 +2,7 @@
 #define _LINUX_PID_H
 
 #include <linux/rcupdate.h>
+#include <linux/atomic.h>
 
 enum pid_type
 {
Index: linux-3.4/include/linux/sysctl.h
===================================================================
--- linux-3.4.orig/include/linux/sysctl.h
+++ linux-3.4/include/linux/sysctl.h
@@ -933,6 +933,7 @@ enum
 #include <linux/rcupdate.h>
 #include <linux/wait.h>
 #include <linux/rbtree.h>
+#include <linux/atomic.h>
 
 /* For the /proc/sys support */
 struct ctl_table;
Index: linux-3.4/net/core/sock.c
===================================================================
--- linux-3.4.orig/net/core/sock.c
+++ linux-3.4/net/core/sock.c
@@ -2139,12 +2139,11 @@ void lock_sock_nested(struct sock *sk, i
 	if (sk->sk_lock.owned)
 		__lock_sock(sk);
 	sk->sk_lock.owned = 1;
-	spin_unlock(&sk->sk_lock.slock);
+	spin_unlock_bh(&sk->sk_lock.slock);
 	/*
 	 * The sk_lock has mutex_lock() semantics here:
 	 */
 	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
-	local_bh_enable();
 }
 EXPORT_SYMBOL(lock_sock_nested);
 
Index: linux-3.4/include/linux/interrupt.h
===================================================================
--- linux-3.4.orig/include/linux/interrupt.h
+++ linux-3.4/include/linux/interrupt.h
@@ -59,6 +59,7 @@
  * IRQF_NO_THREAD - Interrupt cannot be threaded
  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
  *                resume time.
+ * IRQF_NO_SOFTIRQ_CALL - Do not process softirqs in the irq thread context (RT)
  */
 #define IRQF_DISABLED		0x00000020
 #define IRQF_SAMPLE_RANDOM	0x00000040
@@ -73,6 +74,7 @@
 #define IRQF_FORCE_RESUME	0x00008000
 #define IRQF_NO_THREAD		0x00010000
 #define IRQF_EARLY_RESUME	0x00020000
+#define IRQF_NO_SOFTIRQ_CALL	0x00040000
 
 #define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
 
@@ -217,7 +219,7 @@ extern void devm_free_irq(struct device 
 #ifdef CONFIG_LOCKDEP
 # define local_irq_enable_in_hardirq()	do { } while (0)
 #else
-# define local_irq_enable_in_hardirq()	local_irq_enable()
+# define local_irq_enable_in_hardirq()	local_irq_enable_nort()
 #endif
 
 extern void disable_irq_nosync(unsigned int irq);
@@ -394,9 +396,13 @@ static inline int disable_irq_wake(unsig
 
 
 #ifdef CONFIG_IRQ_FORCED_THREADING
-extern bool force_irqthreads;
+# ifndef CONFIG_PREEMPT_RT_BASE
+   extern bool force_irqthreads;
+# else
+#  define force_irqthreads	(true)
+# endif
 #else
-#define force_irqthreads	(0)
+#define force_irqthreads	(false)
 #endif
 
 #ifndef __ARCH_SET_SOFTIRQ_PENDING
@@ -450,8 +456,14 @@ struct softirq_action
 	void	(*action)(struct softirq_action *);
 };
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
+static inline void thread_do_softirq(void) { do_softirq(); }
+#else
+extern void thread_do_softirq(void);
+#endif
+
 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 extern void softirq_init(void);
 extern void __raise_softirq_irqoff(unsigned int nr);
@@ -459,6 +471,8 @@ extern void __raise_softirq_irqoff(unsig
 extern void raise_softirq_irqoff(unsigned int nr);
 extern void raise_softirq(unsigned int nr);
 
+extern void softirq_check_pending_idle(void);
+
 /* This is the worklist that queues up per-cpu softirq work.
  *
  * send_remote_sendirq() adds work to these lists, and
@@ -499,8 +513,9 @@ extern void __send_remote_softirq(struct
      to be executed on some cpu at least once after this.
    * If the tasklet is already scheduled, but its execution is still not
      started, it will be executed only once.
-   * If this tasklet is already running on another CPU (or schedule is called
-     from tasklet itself), it is rescheduled for later.
+   * If this tasklet is already running on another CPU, it is rescheduled
+     for later.
+   * Schedule must not be called from the tasklet itself (a lockup occurs)
    * Tasklet is strictly serialized wrt itself, but not
      wrt another tasklets. If client needs some intertask synchronization,
      he makes it with spinlocks.
@@ -525,27 +540,36 @@ struct tasklet_struct name = { NULL, 0, 
 enum
 {
 	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
-	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_RUN,	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_PENDING	/* Tasklet is pending */
 };
 
-#ifdef CONFIG_SMP
+#define TASKLET_STATEF_SCHED	(1 << TASKLET_STATE_SCHED)
+#define TASKLET_STATEF_RUN	(1 << TASKLET_STATE_RUN)
+#define TASKLET_STATEF_PENDING	(1 << TASKLET_STATE_PENDING)
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
 static inline int tasklet_trylock(struct tasklet_struct *t)
 {
 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
+static inline int tasklet_tryunlock(struct tasklet_struct *t)
+{
+	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
+}
+
 static inline void tasklet_unlock(struct tasklet_struct *t)
 {
 	smp_mb__before_clear_bit(); 
 	clear_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
-static inline void tasklet_unlock_wait(struct tasklet_struct *t)
-{
-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
-}
+extern void tasklet_unlock_wait(struct tasklet_struct *t);
+
 #else
 #define tasklet_trylock(t) 1
+#define tasklet_tryunlock(t)	1
 #define tasklet_unlock_wait(t) do { } while (0)
 #define tasklet_unlock(t) do { } while (0)
 #endif
@@ -594,17 +618,8 @@ static inline void tasklet_disable(struc
 	smp_mb();
 }
 
-static inline void tasklet_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
-
-static inline void tasklet_hi_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
+extern  void tasklet_enable(struct tasklet_struct *t);
+extern  void tasklet_hi_enable(struct tasklet_struct *t);
 
 extern void tasklet_kill(struct tasklet_struct *t);
 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
@@ -636,6 +651,12 @@ void tasklet_hrtimer_cancel(struct taskl
 	tasklet_kill(&ttimer->tasklet);
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+extern void softirq_early_init(void);
+#else
+static inline void softirq_early_init(void) { }
+#endif
+
 /*
  * Autoprobing for irqs:
  *
Index: linux-3.4/net/core/dev.c
===================================================================
--- linux-3.4.orig/net/core/dev.c
+++ linux-3.4/net/core/dev.c
@@ -220,14 +220,14 @@ static inline struct hlist_head *dev_ind
 static inline void rps_lock(struct softnet_data *sd)
 {
 #ifdef CONFIG_RPS
-	spin_lock(&sd->input_pkt_queue.lock);
+	raw_spin_lock(&sd->input_pkt_queue.raw_lock);
 #endif
 }
 
 static inline void rps_unlock(struct softnet_data *sd)
 {
 #ifdef CONFIG_RPS
-	spin_unlock(&sd->input_pkt_queue.lock);
+	raw_spin_unlock(&sd->input_pkt_queue.raw_lock);
 #endif
 }
 
@@ -1803,6 +1803,7 @@ static inline void __netif_reschedule(st
 	sd->output_queue_tailp = &q->next_sched;
 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 
 void __netif_schedule(struct Qdisc *q)
@@ -1824,6 +1825,7 @@ void dev_kfree_skb_irq(struct sk_buff *s
 		sd->completion_queue = skb;
 		raise_softirq_irqoff(NET_TX_SOFTIRQ);
 		local_irq_restore(flags);
+		preempt_check_resched_rt();
 	}
 }
 EXPORT_SYMBOL(dev_kfree_skb_irq);
@@ -2923,6 +2925,7 @@ enqueue:
 	rps_unlock(sd);
 
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 
 	atomic_long_inc(&skb->dev->rx_dropped);
 	kfree_skb(skb);
@@ -2986,16 +2989,46 @@ int netif_rx_ni(struct sk_buff *skb)
 {
 	int err;
 
-	preempt_disable();
+	migrate_disable();
 	err = netif_rx(skb);
 	if (local_softirq_pending())
-		do_softirq();
-	preempt_enable();
+		thread_do_softirq();
+	migrate_enable();
 
 	return err;
 }
 EXPORT_SYMBOL(netif_rx_ni);
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * RT runs ksoftirqd as a real time thread and the root_lock is a
+ * "sleeping spinlock". If the trylock fails then we can go into an
+ * infinite loop when ksoftirqd preempted the task which actually
+ * holds the lock, because we requeue q and raise NET_TX softirq
+ * causing ksoftirqd to loop forever.
+ *
+ * It's safe to use spin_lock on RT here as softirqs run in thread
+ * context and cannot deadlock against the thread which is holding
+ * root_lock.
+ *
+ * On !RT the trylock might fail, but there we bail out from the
+ * softirq loop after 10 attempts which we can't do on RT. And the
+ * task holding root_lock cannot be preempted, so the only downside of
+ * that trylock is that we need 10 loops to decide that we should have
+ * given up in the first one :)
+ */
+static inline int take_root_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+	return 1;
+}
+#else
+static inline int take_root_lock(spinlock_t *lock)
+{
+	return spin_trylock(lock);
+}
+#endif
+
 static void net_tx_action(struct softirq_action *h)
 {
 	struct softnet_data *sd = &__get_cpu_var(softnet_data);
@@ -3034,7 +3067,7 @@ static void net_tx_action(struct softirq
 			head = head->next_sched;
 
 			root_lock = qdisc_lock(q);
-			if (spin_trylock(root_lock)) {
+			if (take_root_lock(root_lock)) {
 				smp_mb__before_clear_bit();
 				clear_bit(__QDISC_STATE_SCHED,
 					  &q->state);
@@ -3353,7 +3386,7 @@ static void flush_backlog(void *arg)
 	skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
 		if (skb->dev == dev) {
 			__skb_unlink(skb, &sd->input_pkt_queue);
-			kfree_skb(skb);
+			__skb_queue_tail(&sd->tofree_queue, skb);
 			input_queue_head_incr(sd);
 		}
 	}
@@ -3362,10 +3395,13 @@ static void flush_backlog(void *arg)
 	skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
 		if (skb->dev == dev) {
 			__skb_unlink(skb, &sd->process_queue);
-			kfree_skb(skb);
+			__skb_queue_tail(&sd->tofree_queue, skb);
 			input_queue_head_incr(sd);
 		}
 	}
+
+	if (!skb_queue_empty(&sd->tofree_queue))
+		raise_softirq_irqoff(NET_RX_SOFTIRQ);
 }
 
 static int napi_gro_complete(struct sk_buff *skb)
@@ -3703,6 +3739,7 @@ static void net_rps_action_and_irq_enabl
 	} else
 #endif
 		local_irq_enable();
+	preempt_check_resched_rt();
 }
 
 static int process_backlog(struct napi_struct *napi, int quota)
@@ -3775,6 +3812,7 @@ void __napi_schedule(struct napi_struct 
 	local_irq_save(flags);
 	____napi_schedule(&__get_cpu_var(softnet_data), n);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(__napi_schedule);
 
@@ -3849,10 +3887,17 @@ static void net_rx_action(struct softirq
 	struct softnet_data *sd = &__get_cpu_var(softnet_data);
 	unsigned long time_limit = jiffies + 2;
 	int budget = netdev_budget;
+	struct sk_buff *skb;
 	void *have;
 
 	local_irq_disable();
 
+	while ((skb = __skb_dequeue(&sd->tofree_queue))) {
+		local_irq_enable();
+		kfree_skb(skb);
+		local_irq_disable();
+	}
+
 	while (!list_empty(&sd->poll_list)) {
 		struct napi_struct *n;
 		int work, weight;
@@ -6269,6 +6314,7 @@ static int dev_cpu_callback(struct notif
 
 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
 	local_irq_enable();
+	preempt_check_resched_rt();
 
 	/* Process offline CPU's input_pkt_queue */
 	while ((skb = __skb_dequeue(&oldsd->process_queue))) {
@@ -6279,6 +6325,9 @@ static int dev_cpu_callback(struct notif
 		netif_rx(skb);
 		input_queue_head_incr(oldsd);
 	}
+	while ((skb = __skb_dequeue(&oldsd->tofree_queue))) {
+		kfree_skb(skb);
+	}
 
 	return NOTIFY_OK;
 }
@@ -6542,8 +6591,9 @@ static int __init net_dev_init(void)
 		struct softnet_data *sd = &per_cpu(softnet_data, i);
 
 		memset(sd, 0, sizeof(*sd));
-		skb_queue_head_init(&sd->input_pkt_queue);
-		skb_queue_head_init(&sd->process_queue);
+		skb_queue_head_init_raw(&sd->input_pkt_queue);
+		skb_queue_head_init_raw(&sd->process_queue);
+		skb_queue_head_init_raw(&sd->tofree_queue);
 		sd->completion_queue = NULL;
 		INIT_LIST_HEAD(&sd->poll_list);
 		sd->output_queue = NULL;
Index: linux-3.4/kernel/softirq.c
===================================================================
--- linux-3.4.orig/kernel/softirq.c
+++ linux-3.4/kernel/softirq.c
@@ -21,9 +21,11 @@
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/rcupdate.h>
+#include <linux/delay.h>
 #include <linux/ftrace.h>
 #include <linux/smp.h>
 #include <linux/tick.h>
+#include <linux/locallock.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>
@@ -61,6 +63,67 @@ char *softirq_to_name[NR_SOFTIRQS] = {
 	"TASKLET", "SCHED", "HRTIMER", "RCU"
 };
 
+#ifdef CONFIG_NO_HZ
+# ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * On preempt-rt a softirq might be blocked on a lock. There might be
+ * no other runnable task on this CPU because the lock owner runs on
+ * some other CPU. So we have to go into idle with the pending bit
+ * set. Therefor we need to check this otherwise we warn about false
+ * positives which confuses users and defeats the whole purpose of
+ * this test.
+ *
+ * This code is called with interrupts disabled.
+ */
+void softirq_check_pending_idle(void)
+{
+	static int rate_limit;
+	u32 warnpending = 0, pending = local_softirq_pending();
+
+	if (rate_limit >= 10)
+		return;
+
+	if (pending) {
+		struct task_struct *tsk;
+
+		tsk = __get_cpu_var(ksoftirqd);
+		/*
+		 * The wakeup code in rtmutex.c wakes up the task
+		 * _before_ it sets pi_blocked_on to NULL under
+		 * tsk->pi_lock. So we need to check for both: state
+		 * and pi_blocked_on.
+		 */
+		raw_spin_lock(&tsk->pi_lock);
+
+		if (!tsk->pi_blocked_on && !(tsk->state == TASK_RUNNING))
+			warnpending = 1;
+
+		raw_spin_unlock(&tsk->pi_lock);
+	}
+
+	if (warnpending) {
+		printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+		       pending);
+		rate_limit++;
+	}
+}
+# else
+/*
+ * On !PREEMPT_RT we just printk rate limited:
+ */
+void softirq_check_pending_idle(void)
+{
+	static int rate_limit;
+
+	if (rate_limit < 10) {
+		printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+		       local_softirq_pending());
+		rate_limit++;
+	}
+}
+# endif
+#endif
+
 /*
  * we cannot loop indefinitely here to avoid userspace starvation,
  * but we also don't want to introduce a worst case 1/HZ latency
@@ -76,6 +139,36 @@ static void wakeup_softirqd(void)
 		wake_up_process(tsk);
 }
 
+static void handle_pending_softirqs(u32 pending, int cpu, int need_rcu_bh_qs)
+{
+	struct softirq_action *h = softirq_vec;
+	unsigned int prev_count = preempt_count();
+
+	local_irq_enable();
+	for ( ; pending; h++, pending >>= 1) {
+		unsigned int vec_nr = h - softirq_vec;
+
+		if (!(pending & 1))
+			continue;
+
+		kstat_incr_softirqs_this_cpu(vec_nr);
+		trace_softirq_entry(vec_nr);
+		h->action(h);
+		trace_softirq_exit(vec_nr);
+		if (unlikely(prev_count != preempt_count())) {
+			printk(KERN_ERR
+ "huh, entered softirq %u %s %p with preempt_count %08x exited with %08x?\n",
+			       vec_nr, softirq_to_name[vec_nr], h->action,
+			       prev_count, (unsigned int) preempt_count());
+			preempt_count() = prev_count;
+		}
+		if (need_rcu_bh_qs)
+			rcu_bh_qs(cpu);
+	}
+	local_irq_disable();
+}
+
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * preempt_count and SOFTIRQ_OFFSET usage:
  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
@@ -206,7 +299,6 @@ EXPORT_SYMBOL(local_bh_enable_ip);
 
 asmlinkage void __do_softirq(void)
 {
-	struct softirq_action *h;
 	__u32 pending;
 	int max_restart = MAX_SOFTIRQ_RESTART;
 	int cpu;
@@ -215,7 +307,7 @@ asmlinkage void __do_softirq(void)
 	account_system_vtime(current);
 
 	__local_bh_disable((unsigned long)__builtin_return_address(0),
-				SOFTIRQ_OFFSET);
+			   SOFTIRQ_OFFSET);
 	lockdep_softirq_enter();
 
 	cpu = smp_processor_id();
@@ -223,36 +315,7 @@ restart:
 	/* Reset the pending bitmask before enabling irqs */
 	set_softirq_pending(0);
 
-	local_irq_enable();
-
-	h = softirq_vec;
-
-	do {
-		if (pending & 1) {
-			unsigned int vec_nr = h - softirq_vec;
-			int prev_count = preempt_count();
-
-			kstat_incr_softirqs_this_cpu(vec_nr);
-
-			trace_softirq_entry(vec_nr);
-			h->action(h);
-			trace_softirq_exit(vec_nr);
-			if (unlikely(prev_count != preempt_count())) {
-				printk(KERN_ERR "huh, entered softirq %u %s %p"
-				       "with preempt_count %08x,"
-				       " exited with %08x?\n", vec_nr,
-				       softirq_to_name[vec_nr], h->action,
-				       prev_count, preempt_count());
-				preempt_count() = prev_count;
-			}
-
-			rcu_bh_qs(cpu);
-		}
-		h++;
-		pending >>= 1;
-	} while (pending);
-
-	local_irq_disable();
+	handle_pending_softirqs(pending, cpu, 1);
 
 	pending = local_softirq_pending();
 	if (pending && --max_restart)
@@ -267,6 +330,26 @@ restart:
 	__local_bh_enable(SOFTIRQ_OFFSET);
 }
 
+/*
+ * Called with preemption disabled from run_ksoftirqd()
+ */
+static int ksoftirqd_do_softirq(int cpu)
+{
+	/*
+	 * Preempt disable stops cpu going offline.
+	 * If already offline, we'll be on wrong CPU:
+	 * don't process.
+	 */
+	if (cpu_is_offline(cpu))
+		return -1;
+
+	local_irq_disable();
+	if (local_softirq_pending())
+		__do_softirq();
+	local_irq_enable();
+	return 0;
+}
+
 #ifndef __ARCH_HAS_DO_SOFTIRQ
 
 asmlinkage void do_softirq(void)
@@ -289,6 +372,191 @@ asmlinkage void do_softirq(void)
 
 #endif
 
+static inline void local_bh_disable_nort(void) { local_bh_disable(); }
+static inline void _local_bh_enable_nort(void) { _local_bh_enable(); }
+static inline void ksoftirqd_set_sched_params(void) { }
+static inline void ksoftirqd_clr_sched_params(void) { }
+
+#else /* !PREEMPT_RT_FULL */
+
+/*
+ * On RT we serialize softirq execution with a cpu local lock
+ */
+static DEFINE_LOCAL_IRQ_LOCK(local_softirq_lock);
+static DEFINE_PER_CPU(struct task_struct *, local_softirq_runner);
+
+static void __do_softirq_common(int need_rcu_bh_qs);
+
+void __do_softirq(void)
+{
+	__do_softirq_common(0);
+}
+
+void __init softirq_early_init(void)
+{
+	local_irq_lock_init(local_softirq_lock);
+}
+
+void local_bh_disable(void)
+{
+	migrate_disable();
+	current->softirq_nestcnt++;
+}
+EXPORT_SYMBOL(local_bh_disable);
+
+void local_bh_enable(void)
+{
+	if (WARN_ON(current->softirq_nestcnt == 0))
+		return;
+
+	if ((current->softirq_nestcnt == 1) &&
+	    local_softirq_pending() &&
+	    local_trylock(local_softirq_lock)) {
+
+		local_irq_disable();
+		if (local_softirq_pending())
+			__do_softirq();
+		local_irq_enable();
+		local_unlock(local_softirq_lock);
+		WARN_ON(current->softirq_nestcnt != 1);
+	}
+	current->softirq_nestcnt--;
+	migrate_enable();
+}
+EXPORT_SYMBOL(local_bh_enable);
+
+void local_bh_enable_ip(unsigned long ip)
+{
+	local_bh_enable();
+}
+EXPORT_SYMBOL(local_bh_enable_ip);
+
+void _local_bh_enable(void)
+{
+	current->softirq_nestcnt--;
+	migrate_enable();
+}
+EXPORT_SYMBOL(_local_bh_enable);
+
+/* For tracing */
+int notrace __in_softirq(void)
+{
+	if (__get_cpu_var(local_softirq_lock).owner == current)
+		return __get_cpu_var(local_softirq_lock).nestcnt;
+	return 0;
+}
+
+int in_serving_softirq(void)
+{
+	int res;
+
+	preempt_disable();
+	res = __get_cpu_var(local_softirq_runner) == current;
+	preempt_enable();
+	return res;
+}
+EXPORT_SYMBOL(in_serving_softirq);
+
+/*
+ * Called with bh and local interrupts disabled. For full RT cpu must
+ * be pinned.
+ */
+static void __do_softirq_common(int need_rcu_bh_qs)
+{
+	u32 pending = local_softirq_pending();
+	int cpu = smp_processor_id();
+
+	current->softirq_nestcnt++;
+
+	/* Reset the pending bitmask before enabling irqs */
+	set_softirq_pending(0);
+
+	__get_cpu_var(local_softirq_runner) = current;
+
+	lockdep_softirq_enter();
+
+	handle_pending_softirqs(pending, cpu, need_rcu_bh_qs);
+
+	pending = local_softirq_pending();
+	if (pending)
+		wakeup_softirqd();
+
+	lockdep_softirq_exit();
+	__get_cpu_var(local_softirq_runner) = NULL;
+
+	current->softirq_nestcnt--;
+}
+
+static int __thread_do_softirq(int cpu)
+{
+	/*
+	 * Prevent the current cpu from going offline.
+	 * pin_current_cpu() can reenable preemption and block on the
+	 * hotplug mutex. When it returns, the current cpu is
+	 * pinned. It might be the wrong one, but the offline check
+	 * below catches that.
+	 */
+	pin_current_cpu();
+	/*
+	 * If called from ksoftirqd (cpu >= 0) we need to check
+	 * whether we are on the wrong cpu due to cpu offlining. If
+	 * called via thread_do_softirq() no action required.
+	 */
+	if (cpu >= 0 && cpu_is_offline(cpu)) {
+		unpin_current_cpu();
+		return -1;
+	}
+	preempt_enable();
+	local_lock(local_softirq_lock);
+	local_irq_disable();
+	/*
+	 * We cannot switch stacks on RT as we want to be able to
+	 * schedule!
+	 */
+	if (local_softirq_pending())
+		__do_softirq_common(cpu >= 0);
+	local_unlock(local_softirq_lock);
+	unpin_current_cpu();
+	preempt_disable();
+	local_irq_enable();
+	return 0;
+}
+
+/*
+ * Called from netif_rx_ni(). Preemption enabled.
+ */
+void thread_do_softirq(void)
+{
+	if (!in_serving_softirq()) {
+		preempt_disable();
+		__thread_do_softirq(-1);
+		preempt_enable();
+	}
+}
+
+static int ksoftirqd_do_softirq(int cpu)
+{
+	return __thread_do_softirq(cpu);
+}
+
+static inline void local_bh_disable_nort(void) { }
+static inline void _local_bh_enable_nort(void) { }
+
+static inline void ksoftirqd_set_sched_params(void)
+{
+	struct sched_param param = { .sched_priority = 1 };
+
+	sched_setscheduler(current, SCHED_FIFO, &param);
+}
+
+static inline void ksoftirqd_clr_sched_params(void)
+{
+	struct sched_param param = { .sched_priority = 0 };
+
+	sched_setscheduler(current, SCHED_NORMAL, &param);
+}
+
+#endif /* PREEMPT_RT_FULL */
 /*
  * Enter an interrupt context.
  */
@@ -302,9 +570,9 @@ void irq_enter(void)
 		 * Prevent raise_softirq from needlessly waking up ksoftirqd
 		 * here, as softirq will be serviced on return from interrupt.
 		 */
-		local_bh_disable();
+		local_bh_disable_nort();
 		tick_check_idle(cpu);
-		_local_bh_enable();
+		_local_bh_enable_nort();
 	}
 
 	__irq_enter();
@@ -312,6 +580,7 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
+#ifndef CONFIG_PREEMPT_RT_FULL
 	if (!force_irqthreads) {
 #ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
 		__do_softirq();
@@ -324,6 +593,9 @@ static inline void invoke_softirq(void)
 		wakeup_softirqd();
 		__local_bh_enable(SOFTIRQ_OFFSET);
 	}
+#else
+		wakeup_softirqd();
+#endif
 }
 
 /*
@@ -398,15 +670,45 @@ struct tasklet_head
 static DEFINE_PER_CPU(struct tasklet_head, tasklet_vec);
 static DEFINE_PER_CPU(struct tasklet_head, tasklet_hi_vec);
 
+static void inline
+__tasklet_common_schedule(struct tasklet_struct *t, struct tasklet_head *head, unsigned int nr)
+{
+	if (tasklet_trylock(t)) {
+again:
+		/* We may have been preempted before tasklet_trylock
+		 * and __tasklet_action may have already run.
+		 * So double check the sched bit while the takslet
+		 * is locked before adding it to the list.
+		 */
+		if (test_bit(TASKLET_STATE_SCHED, &t->state)) {
+			t->next = NULL;
+			*head->tail = t;
+			head->tail = &(t->next);
+			raise_softirq_irqoff(nr);
+			tasklet_unlock(t);
+		} else {
+			/* This is subtle. If we hit the corner case above
+			 * It is possible that we get preempted right here,
+			 * and another task has successfully called
+			 * tasklet_schedule(), then this function, and
+			 * failed on the trylock. Thus we must be sure
+			 * before releasing the tasklet lock, that the
+			 * SCHED_BIT is clear. Otherwise the tasklet
+			 * may get its SCHED_BIT set, but not added to the
+			 * list
+			 */
+			if (!tasklet_tryunlock(t))
+				goto again;
+		}
+	}
+}
+
 void __tasklet_schedule(struct tasklet_struct *t)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
-	t->next = NULL;
-	*__this_cpu_read(tasklet_vec.tail) = t;
-	__this_cpu_write(tasklet_vec.tail, &(t->next));
-	raise_softirq_irqoff(TASKLET_SOFTIRQ);
+	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_vec), TASKLET_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
@@ -417,10 +719,7 @@ void __tasklet_hi_schedule(struct taskle
 	unsigned long flags;
 
 	local_irq_save(flags);
-	t->next = NULL;
-	*__this_cpu_read(tasklet_hi_vec.tail) = t;
-	__this_cpu_write(tasklet_hi_vec.tail,  &(t->next));
-	raise_softirq_irqoff(HI_SOFTIRQ);
+	__tasklet_common_schedule(t, &__get_cpu_var(tasklet_hi_vec), HI_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
@@ -428,50 +727,119 @@ EXPORT_SYMBOL(__tasklet_hi_schedule);
 
 void __tasklet_hi_schedule_first(struct tasklet_struct *t)
 {
-	BUG_ON(!irqs_disabled());
-
-	t->next = __this_cpu_read(tasklet_hi_vec.head);
-	__this_cpu_write(tasklet_hi_vec.head, t);
-	__raise_softirq_irqoff(HI_SOFTIRQ);
+	__tasklet_hi_schedule(t);
 }
 
 EXPORT_SYMBOL(__tasklet_hi_schedule_first);
 
-static void tasklet_action(struct softirq_action *a)
+void  tasklet_enable(struct tasklet_struct *t)
 {
-	struct tasklet_struct *list;
+	if (!atomic_dec_and_test(&t->count))
+		return;
+	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
+		tasklet_schedule(t);
+}
 
-	local_irq_disable();
-	list = __this_cpu_read(tasklet_vec.head);
-	__this_cpu_write(tasklet_vec.head, NULL);
-	__this_cpu_write(tasklet_vec.tail, &__get_cpu_var(tasklet_vec).head);
-	local_irq_enable();
+EXPORT_SYMBOL(tasklet_enable);
+
+void  tasklet_hi_enable(struct tasklet_struct *t)
+{
+	if (!atomic_dec_and_test(&t->count))
+		return;
+	if (test_and_clear_bit(TASKLET_STATE_PENDING, &t->state))
+		tasklet_hi_schedule(t);
+}
+
+EXPORT_SYMBOL(tasklet_hi_enable);
+
+static void
+__tasklet_action(struct softirq_action *a, struct tasklet_struct *list)
+{
+	int loops = 1000000;
 
 	while (list) {
 		struct tasklet_struct *t = list;
 
 		list = list->next;
 
-		if (tasklet_trylock(t)) {
-			if (!atomic_read(&t->count)) {
-				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
-					BUG();
-				t->func(t->data);
-				tasklet_unlock(t);
-				continue;
-			}
-			tasklet_unlock(t);
+		/*
+		 * Should always succeed - after a tasklist got on the
+		 * list (after getting the SCHED bit set from 0 to 1),
+		 * nothing but the tasklet softirq it got queued to can
+		 * lock it:
+		 */
+		if (!tasklet_trylock(t)) {
+			WARN_ON(1);
+			continue;
 		}
 
-		local_irq_disable();
 		t->next = NULL;
-		*__this_cpu_read(tasklet_vec.tail) = t;
-		__this_cpu_write(tasklet_vec.tail, &(t->next));
-		__raise_softirq_irqoff(TASKLET_SOFTIRQ);
-		local_irq_enable();
+
+		/*
+		 * If we cannot handle the tasklet because it's disabled,
+		 * mark it as pending. tasklet_enable() will later
+		 * re-schedule the tasklet.
+		 */
+		if (unlikely(atomic_read(&t->count))) {
+out_disabled:
+			/* implicit unlock: */
+			wmb();
+			t->state = TASKLET_STATEF_PENDING;
+			continue;
+		}
+
+		/*
+		 * After this point on the tasklet might be rescheduled
+		 * on another CPU, but it can only be added to another
+		 * CPU's tasklet list if we unlock the tasklet (which we
+		 * dont do yet).
+		 */
+		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+			WARN_ON(1);
+
+again:
+		t->func(t->data);
+
+		/*
+		 * Try to unlock the tasklet. We must use cmpxchg, because
+		 * another CPU might have scheduled or disabled the tasklet.
+		 * We only allow the STATE_RUN -> 0 transition here.
+		 */
+		while (!tasklet_tryunlock(t)) {
+			/*
+			 * If it got disabled meanwhile, bail out:
+			 */
+			if (atomic_read(&t->count))
+				goto out_disabled;
+			/*
+			 * If it got scheduled meanwhile, re-execute
+			 * the tasklet function:
+			 */
+			if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+				goto again;
+			if (!--loops) {
+				printk("hm, tasklet state: %08lx\n", t->state);
+				WARN_ON(1);
+				tasklet_unlock(t);
+				break;
+			}
+		}
 	}
 }
 
+static void tasklet_action(struct softirq_action *a)
+{
+	struct tasklet_struct *list;
+
+	local_irq_disable();
+	list = __get_cpu_var(tasklet_vec).head;
+	__get_cpu_var(tasklet_vec).head = NULL;
+	__get_cpu_var(tasklet_vec).tail = &__get_cpu_var(tasklet_vec).head;
+	local_irq_enable();
+
+	__tasklet_action(a, list);
+}
+
 static void tasklet_hi_action(struct softirq_action *a)
 {
 	struct tasklet_struct *list;
@@ -482,29 +850,7 @@ static void tasklet_hi_action(struct sof
 	__this_cpu_write(tasklet_hi_vec.tail, &__get_cpu_var(tasklet_hi_vec).head);
 	local_irq_enable();
 
-	while (list) {
-		struct tasklet_struct *t = list;
-
-		list = list->next;
-
-		if (tasklet_trylock(t)) {
-			if (!atomic_read(&t->count)) {
-				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
-					BUG();
-				t->func(t->data);
-				tasklet_unlock(t);
-				continue;
-			}
-			tasklet_unlock(t);
-		}
-
-		local_irq_disable();
-		t->next = NULL;
-		*__this_cpu_read(tasklet_hi_vec.tail) = t;
-		__this_cpu_write(tasklet_hi_vec.tail, &(t->next));
-		__raise_softirq_irqoff(HI_SOFTIRQ);
-		local_irq_enable();
-	}
+	__tasklet_action(a, list);
 }
 
 
@@ -527,7 +873,7 @@ void tasklet_kill(struct tasklet_struct 
 
 	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
 		do {
-			yield();
+			msleep(1);
 		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
 	}
 	tasklet_unlock_wait(t);
@@ -733,28 +1079,39 @@ void __init softirq_init(void)
 	open_softirq(HI_SOFTIRQ, tasklet_hi_action);
 }
 
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
+void tasklet_unlock_wait(struct tasklet_struct *t)
+{
+	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+		/*
+		 * Hack for now to avoid this busy-loop:
+		 */
+#ifdef CONFIG_PREEMPT_RT_FULL
+		msleep(1);
+#else
+		barrier();
+#endif
+	}
+}
+EXPORT_SYMBOL(tasklet_unlock_wait);
+#endif
+
 static int run_ksoftirqd(void * __bind_cpu)
 {
+	ksoftirqd_set_sched_params();
+
 	set_current_state(TASK_INTERRUPTIBLE);
 
 	while (!kthread_should_stop()) {
 		preempt_disable();
-		if (!local_softirq_pending()) {
+		if (!local_softirq_pending())
 			schedule_preempt_disabled();
-		}
 
 		__set_current_state(TASK_RUNNING);
 
 		while (local_softirq_pending()) {
-			/* Preempt disable stops cpu going offline.
-			   If already offline, we'll be on wrong CPU:
-			   don't process */
-			if (cpu_is_offline((long)__bind_cpu))
+			if (ksoftirqd_do_softirq((long) __bind_cpu))
 				goto wait_to_die;
-			local_irq_disable();
-			if (local_softirq_pending())
-				__do_softirq();
-			local_irq_enable();
 			sched_preempt_enable_no_resched();
 			cond_resched();
 			preempt_disable();
@@ -768,6 +1125,7 @@ static int run_ksoftirqd(void * __bind_c
 
 wait_to_die:
 	preempt_enable();
+	ksoftirqd_clr_sched_params();
 	/* Wait for kthread_stop */
 	set_current_state(TASK_INTERRUPTIBLE);
 	while (!kthread_should_stop()) {
@@ -844,9 +1202,8 @@ static int __cpuinit cpu_callback(struct
 	int hotcpu = (unsigned long)hcpu;
 	struct task_struct *p;
 
-	switch (action) {
+	switch (action & ~CPU_TASKS_FROZEN) {
 	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
 		p = kthread_create_on_node(run_ksoftirqd,
 					   hcpu,
 					   cpu_to_node(hotcpu),
@@ -859,19 +1216,16 @@ static int __cpuinit cpu_callback(struct
   		per_cpu(ksoftirqd, hotcpu) = p;
  		break;
 	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
 		wake_up_process(per_cpu(ksoftirqd, hotcpu));
 		break;
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
 		if (!per_cpu(ksoftirqd, hotcpu))
 			break;
 		/* Unbind so it can run.  Fall thru. */
 		kthread_bind(per_cpu(ksoftirqd, hotcpu),
 			     cpumask_any(cpu_online_mask));
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN: {
+	case CPU_POST_DEAD: {
 		static const struct sched_param param = {
 			.sched_priority = MAX_RT_PRIO-1
 		};
Index: linux-3.4/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-3.4/arch/x86/kernel/apic/io_apic.c
@@ -2555,7 +2555,8 @@ atomic_t irq_mis_count;
 static inline bool ioapic_irqd_mask(struct irq_data *data, struct irq_cfg *cfg)
 {
 	/* If we are moving the irq we need to mask it */
-	if (unlikely(irqd_is_setaffinity_pending(data))) {
+	if (unlikely(irqd_is_setaffinity_pending(data) &&
+		     !irqd_irq_inprogress(data))) {
 		mask_ioapic(cfg);
 		return true;
 	}
Index: linux-3.4/arch/x86/kernel/traps.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/traps.c
+++ linux-3.4/arch/x86/kernel/traps.c
@@ -87,9 +87,21 @@ static inline void conditional_sti(struc
 		local_irq_enable();
 }
 
-static inline void preempt_conditional_sti(struct pt_regs *regs)
+static inline void conditional_sti_ist(struct pt_regs *regs)
 {
+#ifdef CONFIG_X86_64
+	/*
+	 * X86_64 uses a per CPU stack on the IST for certain traps
+	 * like int3. The task can not be preempted when using one
+	 * of these stacks, thus preemption must be disabled, otherwise
+	 * the stack can be corrupted if the task is scheduled out,
+	 * and another task comes in and uses this stack.
+	 *
+	 * On x86_32 the task keeps its own stack and it is OK if the
+	 * task schedules out.
+	 */
 	inc_preempt_count();
+#endif
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_enable();
 }
@@ -100,11 +112,13 @@ static inline void conditional_cli(struc
 		local_irq_disable();
 }
 
-static inline void preempt_conditional_cli(struct pt_regs *regs)
+static inline void conditional_cli_ist(struct pt_regs *regs)
 {
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_disable();
+#ifdef CONFIG_X86_64
 	dec_preempt_count();
+#endif
 }
 
 static void __kprobes
@@ -226,9 +240,9 @@ dotraplinkage void do_stack_segment(stru
 	if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
 			X86_TRAP_SS, SIGBUS) == NOTIFY_STOP)
 		return;
-	preempt_conditional_sti(regs);
+	conditional_sti_ist(regs);
 	do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
-	preempt_conditional_cli(regs);
+	conditional_cli_ist(regs);
 }
 
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
@@ -320,9 +334,9 @@ dotraplinkage void __kprobes do_int3(str
 	 * as we may switch to the interrupt stack.
 	 */
 	debug_stack_usage_inc();
-	preempt_conditional_sti(regs);
+	conditional_sti_ist(regs);
 	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
-	preempt_conditional_cli(regs);
+	conditional_cli_ist(regs);
 	debug_stack_usage_dec();
 }
 
@@ -423,12 +437,12 @@ dotraplinkage void __kprobes do_debug(st
 	debug_stack_usage_inc();
 
 	/* It's safe to allow irq's after DR6 has been saved */
-	preempt_conditional_sti(regs);
+	conditional_sti_ist(regs);
 
 	if (regs->flags & X86_VM_MASK) {
 		handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
 					X86_TRAP_DB);
-		preempt_conditional_cli(regs);
+		conditional_cli_ist(regs);
 		debug_stack_usage_dec();
 		return;
 	}
@@ -448,7 +462,7 @@ dotraplinkage void __kprobes do_debug(st
 	si_code = get_si_code(tsk->thread.debugreg6);
 	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
 		send_sigtrap(tsk, regs, error_code, si_code);
-	preempt_conditional_cli(regs);
+	conditional_cli_ist(regs);
 	debug_stack_usage_dec();
 
 	return;
Index: linux-3.4/drivers/usb/gadget/ci13xxx_udc.c
===================================================================
--- linux-3.4.orig/drivers/usb/gadget/ci13xxx_udc.c
+++ linux-3.4/drivers/usb/gadget/ci13xxx_udc.c
@@ -834,7 +834,7 @@ static struct {
 } dbg_data = {
 	.idx = 0,
 	.tty = 0,
-	.lck = __RW_LOCK_UNLOCKED(lck)
+	.lck = __RW_LOCK_UNLOCKED(dbg_data.lck)
 };
 
 /**
Index: linux-3.4/fs/file.c
===================================================================
--- linux-3.4.orig/fs/file.c
+++ linux-3.4/fs/file.c
@@ -105,14 +105,14 @@ void free_fdtable_rcu(struct rcu_head *r
 		kfree(fdt->open_fds);
 		kfree(fdt);
 	} else {
-		fddef = &get_cpu_var(fdtable_defer_list);
+		fddef = &per_cpu(fdtable_defer_list, get_cpu_light());
 		spin_lock(&fddef->lock);
 		fdt->next = fddef->next;
 		fddef->next = fdt;
 		/* vmallocs are handled from the workqueue context */
 		schedule_work(&fddef->wq);
 		spin_unlock(&fddef->lock);
-		put_cpu_var(fdtable_defer_list);
+		put_cpu_light();
 	}
 }
 
@@ -421,7 +421,7 @@ struct files_struct init_files = {
 		.close_on_exec	= init_files.close_on_exec_init,
 		.open_fds	= init_files.open_fds_init,
 	},
-	.file_lock	= __SPIN_LOCK_UNLOCKED(init_task.file_lock),
+	.file_lock	= __SPIN_LOCK_UNLOCKED(init_files.file_lock),
 };
 
 /*
Index: linux-3.4/include/linux/idr.h
===================================================================
--- linux-3.4.orig/include/linux/idr.h
+++ linux-3.4/include/linux/idr.h
@@ -136,7 +136,7 @@ struct ida {
 	struct ida_bitmap	*free_bitmap;
 };
 
-#define IDA_INIT(name)		{ .idr = IDR_INIT(name), .free_bitmap = NULL, }
+#define IDA_INIT(name)		{ .idr = IDR_INIT((name).idr), .free_bitmap = NULL, }
 #define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)
 
 int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
Index: linux-3.4/kernel/cred.c
===================================================================
--- linux-3.4.orig/kernel/cred.c
+++ linux-3.4/kernel/cred.c
@@ -36,7 +36,7 @@ static struct kmem_cache *cred_jar;
 static struct thread_group_cred init_tgcred = {
 	.usage	= ATOMIC_INIT(2),
 	.tgid	= 0,
-	.lock	= __SPIN_LOCK_UNLOCKED(init_cred.tgcred.lock),
+	.lock	= __SPIN_LOCK_UNLOCKED(init_tgcred.lock),
 };
 #endif
 
Index: linux-3.4/drivers/pci/access.c
===================================================================
--- linux-3.4.orig/drivers/pci/access.c
+++ linux-3.4/drivers/pci/access.c
@@ -463,7 +463,7 @@ void pci_cfg_access_unlock(struct pci_de
 	WARN_ON(!dev->block_cfg_access);
 
 	dev->block_cfg_access = 0;
-	wake_up_all(&pci_cfg_wait);
+	wake_up_all_locked(&pci_cfg_wait);
 	raw_spin_unlock_irqrestore(&pci_lock, flags);
 }
 EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
Index: linux-3.4/Documentation/trace/histograms.txt
===================================================================
--- /dev/null
+++ linux-3.4/Documentation/trace/histograms.txt
@@ -0,0 +1,186 @@
+		Using the Linux Kernel Latency Histograms
+
+
+This document gives a short explanation how to enable, configure and use
+latency histograms. Latency histograms are primarily relevant in the
+context of real-time enabled kernels (CONFIG_PREEMPT/CONFIG_PREEMPT_RT)
+and are used in the quality management of the Linux real-time
+capabilities.
+
+
+* Purpose of latency histograms
+
+A latency histogram continuously accumulates the frequencies of latency
+data. There are two types of histograms
+- potential sources of latencies
+- effective latencies
+
+
+* Potential sources of latencies
+
+Potential sources of latencies are code segments where interrupts,
+preemption or both are disabled (aka critical sections). To create
+histograms of potential sources of latency, the kernel stores the time
+stamp at the start of a critical section, determines the time elapsed
+when the end of the section is reached, and increments the frequency
+counter of that latency value - irrespective of whether any concurrently
+running process is affected by latency or not.
+- Configuration items (in the Kernel hacking/Tracers submenu)
+  CONFIG_INTERRUPT_OFF_LATENCY
+  CONFIG_PREEMPT_OFF_LATENCY
+
+
+* Effective latencies
+
+Effective latencies are actually occuring during wakeup of a process. To
+determine effective latencies, the kernel stores the time stamp when a
+process is scheduled to be woken up, and determines the duration of the
+wakeup time shortly before control is passed over to this process. Note
+that the apparent latency in user space may be somewhat longer, since the
+process may be interrupted after control is passed over to it but before
+the execution in user space takes place. Simply measuring the interval
+between enqueuing and wakeup may also not appropriate in cases when a
+process is scheduled as a result of a timer expiration. The timer may have
+missed its deadline, e.g. due to disabled interrupts, but this latency
+would not be registered. Therefore, the offsets of missed timers are
+recorded in a separate histogram. If both wakeup latency and missed timer
+offsets are configured and enabled, a third histogram may be enabled that
+records the overall latency as a sum of the timer latency, if any, and the
+wakeup latency. This histogram is called "timerandwakeup".
+- Configuration items (in the Kernel hacking/Tracers submenu)
+  CONFIG_WAKEUP_LATENCY
+  CONFIG_MISSED_TIMER_OFSETS
+
+
+* Usage
+
+The interface to the administration of the latency histograms is located
+in the debugfs file system. To mount it, either enter
+
+mount -t sysfs nodev /sys
+mount -t debugfs nodev /sys/kernel/debug
+
+from shell command line level, or add
+
+nodev	/sys			sysfs	defaults	0 0
+nodev	/sys/kernel/debug	debugfs	defaults	0 0
+
+to the file /etc/fstab. All latency histogram related files are then
+available in the directory /sys/kernel/debug/tracing/latency_hist. A
+particular histogram type is enabled by writing non-zero to the related
+variable in the /sys/kernel/debug/tracing/latency_hist/enable directory.
+Select "preemptirqsoff" for the histograms of potential sources of
+latencies and "wakeup" for histograms of effective latencies etc. The
+histogram data - one per CPU - are available in the files
+
+/sys/kernel/debug/tracing/latency_hist/preemptoff/CPUx
+/sys/kernel/debug/tracing/latency_hist/irqsoff/CPUx
+/sys/kernel/debug/tracing/latency_hist/preemptirqsoff/CPUx
+/sys/kernel/debug/tracing/latency_hist/wakeup/CPUx
+/sys/kernel/debug/tracing/latency_hist/wakeup/sharedprio/CPUx
+/sys/kernel/debug/tracing/latency_hist/missed_timer_offsets/CPUx
+/sys/kernel/debug/tracing/latency_hist/timerandwakeup/CPUx
+
+The histograms are reset by writing non-zero to the file "reset" in a
+particular latency directory. To reset all latency data, use
+
+#!/bin/sh
+
+TRACINGDIR=/sys/kernel/debug/tracing
+HISTDIR=$TRACINGDIR/latency_hist
+
+if test -d $HISTDIR
+then
+  cd $HISTDIR
+  for i in `find . | grep /reset$`
+  do
+    echo 1 >$i
+  done
+fi
+
+
+* Data format
+
+Latency data are stored with a resolution of one microsecond. The
+maximum latency is 10,240 microseconds. The data are only valid, if the
+overflow register is empty. Every output line contains the latency in
+microseconds in the first row and the number of samples in the second
+row. To display only lines with a positive latency count, use, for
+example,
+
+grep -v " 0$" /sys/kernel/debug/tracing/latency_hist/preemptoff/CPU0
+
+#Minimum latency: 0 microseconds.
+#Average latency: 0 microseconds.
+#Maximum latency: 25 microseconds.
+#Total samples: 3104770694
+#There are 0 samples greater or equal than 10240 microseconds
+#usecs	         samples
+    0	      2984486876
+    1	        49843506
+    2	        58219047
+    3	         5348126
+    4	         2187960
+    5	         3388262
+    6	          959289
+    7	          208294
+    8	           40420
+    9	            4485
+   10	           14918
+   11	           18340
+   12	           25052
+   13	           19455
+   14	            5602
+   15	             969
+   16	              47
+   17	              18
+   18	              14
+   19	               1
+   20	               3
+   21	               2
+   22	               5
+   23	               2
+   25	               1
+
+
+* Wakeup latency of a selected process
+
+To only collect wakeup latency data of a particular process, write the
+PID of the requested process to
+
+/sys/kernel/debug/tracing/latency_hist/wakeup/pid
+
+PIDs are not considered, if this variable is set to 0.
+
+
+* Details of the process with the highest wakeup latency so far
+
+Selected data of the process that suffered from the highest wakeup
+latency that occurred in a particular CPU are available in the file
+
+/sys/kernel/debug/tracing/latency_hist/wakeup/max_latency-CPUx.
+
+In addition, other relevant system data at the time when the
+latency occurred are given.
+
+The format of the data is (all in one line):
+<PID> <Priority> <Latency> (<Timeroffset>) <Command> \
+<- <PID> <Priority> <Command> <Timestamp>
+
+The value of <Timeroffset> is only relevant in the combined timer
+and wakeup latency recording. In the wakeup recording, it is
+always 0, in the missed_timer_offsets recording, it is the same
+as <Latency>.
+
+When retrospectively searching for the origin of a latency and
+tracing was not enabled, it may be helpful to know the name and
+some basic data of the task that (finally) was switching to the
+late real-tlme task. In addition to the victim's data, also the
+data of the possible culprit are therefore displayed after the
+"<-" symbol.
+
+Finally, the timestamp of the time when the latency occurred
+in <seconds>.<microseconds> after the most recent system boot
+is provided.
+
+These data are also reset when the wakeup histogram is reset.
Index: linux-3.4/include/trace/events/hist.h
===================================================================
--- /dev/null
+++ linux-3.4/include/trace/events/hist.h
@@ -0,0 +1,69 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hist
+
+#if !defined(_TRACE_HIST_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HIST_H
+
+#include "latency_hist.h"
+#include <linux/tracepoint.h>
+
+#if !defined(CONFIG_PREEMPT_OFF_HIST) && !defined(CONFIG_INTERRUPT_OFF_HIST)
+#define trace_preemptirqsoff_hist(a,b)
+#else
+TRACE_EVENT(preemptirqsoff_hist,
+
+	TP_PROTO(int reason, int starthist),
+
+	TP_ARGS(reason, starthist),
+
+	TP_STRUCT__entry(
+		__field(int,	reason	)
+		__field(int,	starthist	)
+	),
+
+	TP_fast_assign(
+		__entry->reason		= reason;
+		__entry->starthist	= starthist;
+	),
+
+	TP_printk("reason=%s starthist=%s", getaction(__entry->reason),
+		  __entry->starthist ? "start" : "stop")
+);
+#endif
+
+#ifndef CONFIG_MISSED_TIMER_OFFSETS_HIST
+#define trace_hrtimer_interrupt(a,b,c,d)
+#else
+TRACE_EVENT(hrtimer_interrupt,
+
+	TP_PROTO(int cpu, long long offset, struct task_struct *curr, struct task_struct *task),
+
+	TP_ARGS(cpu, offset, curr, task),
+
+	TP_STRUCT__entry(
+		__field(int,		cpu	)
+		__field(long long,	offset	)
+		__array(char,		ccomm,	TASK_COMM_LEN)
+		__field(int,		cprio	)
+		__array(char,		tcomm,	TASK_COMM_LEN)
+		__field(int,		tprio	)
+	),
+
+	TP_fast_assign(
+		__entry->cpu	= cpu;
+		__entry->offset	= offset;
+		memcpy(__entry->ccomm, curr->comm, TASK_COMM_LEN);
+		__entry->cprio  = curr->prio;
+		memcpy(__entry->tcomm, task != NULL ? task->comm : "<none>", task != NULL ? TASK_COMM_LEN : 7);
+		__entry->tprio  = task != NULL ? task->prio : -1;
+	),
+
+	TP_printk("cpu=%d offset=%lld curr=%s[%d] thread=%s[%d]",
+		__entry->cpu, __entry->offset, __entry->ccomm, __entry->cprio, __entry->tcomm, __entry->tprio)
+);
+#endif
+
+#endif /* _TRACE_HIST_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
Index: linux-3.4/include/trace/events/latency_hist.h
===================================================================
--- /dev/null
+++ linux-3.4/include/trace/events/latency_hist.h
@@ -0,0 +1,30 @@
+#ifndef _LATENCY_HIST_H
+#define _LATENCY_HIST_H
+
+enum hist_action {
+	IRQS_ON,
+	PREEMPT_ON,
+	TRACE_STOP,
+	IRQS_OFF,
+	PREEMPT_OFF,
+	TRACE_START,
+};
+
+static char *actions[] = {
+	"IRQS_ON",
+	"PREEMPT_ON",
+	"TRACE_STOP",
+	"IRQS_OFF",
+	"PREEMPT_OFF",
+	"TRACE_START",
+};
+
+static inline char *getaction(int action)
+{
+	if (action >= 0 && action <= sizeof(actions)/sizeof(actions[0]))
+		return(actions[action]);
+	return("unknown");
+}
+
+#endif /* _LATENCY_HIST_H */
+
Index: linux-3.4/kernel/hrtimer.c
===================================================================
--- linux-3.4.orig/kernel/hrtimer.c
+++ linux-3.4/kernel/hrtimer.c
@@ -49,6 +49,7 @@
 #include <asm/uaccess.h>
 
 #include <trace/events/timer.h>
+#include <trace/events/hist.h>
 
 /*
  * The timer bases:
@@ -588,8 +589,7 @@ static int hrtimer_reprogram(struct hrti
 	 * When the callback is running, we do not reprogram the clock event
 	 * device. The timer callback is either running on a different CPU or
 	 * the callback is executed in the hrtimer_interrupt context. The
-	 * reprogramming is handled either by the softirq, which called the
-	 * callback or at the end of the hrtimer_interrupt.
+	 * reprogramming is handled at the end of the hrtimer_interrupt.
 	 */
 	if (hrtimer_callback_running(timer))
 		return 0;
@@ -624,6 +624,9 @@ static int hrtimer_reprogram(struct hrti
 	return res;
 }
 
+static void __run_hrtimer(struct hrtimer *timer, ktime_t *now);
+static int hrtimer_rt_defer(struct hrtimer *timer);
+
 /*
  * Initialize the high resolution related parts of cpu_base
  */
@@ -644,14 +647,23 @@ static inline int hrtimer_enqueue_reprog
 					    int wakeup)
 {
 	if (base->cpu_base->hres_active && hrtimer_reprogram(timer, base)) {
-		if (wakeup) {
-			raw_spin_unlock(&base->cpu_base->lock);
-			raise_softirq_irqoff(HRTIMER_SOFTIRQ);
-			raw_spin_lock(&base->cpu_base->lock);
-		} else
-			__raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+		if (!wakeup)
+			return -ETIME;
 
-		return 1;
+#ifdef CONFIG_PREEMPT_RT_BASE
+		/*
+		 * Move softirq based timers away from the rbtree in
+		 * case it expired already. Otherwise we would have a
+		 * stale base->first entry until the softirq runs.
+		 */
+		if (!hrtimer_rt_defer(timer))
+			return -ETIME;
+#endif
+		raw_spin_unlock(&base->cpu_base->lock);
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+		raw_spin_lock(&base->cpu_base->lock);
+
+		return 0;
 	}
 
 	return 0;
@@ -732,6 +744,11 @@ static inline int hrtimer_enqueue_reprog
 }
 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base) { }
 static inline void retrigger_next_event(void *arg) { }
+static inline int hrtimer_reprogram(struct hrtimer *timer,
+				    struct hrtimer_clock_base *base)
+{
+	return 0;
+}
 
 #endif /* CONFIG_HIGH_RES_TIMERS */
 
@@ -846,6 +863,32 @@ u64 hrtimer_forward(struct hrtimer *time
 }
 EXPORT_SYMBOL_GPL(hrtimer_forward);
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+# define wake_up_timer_waiters(b)	wake_up(&(b)->wait)
+
+/**
+ * hrtimer_wait_for_timer - Wait for a running timer
+ *
+ * @timer:	timer to wait for
+ *
+ * The function waits in case the timers callback function is
+ * currently executed on the waitqueue of the timer base. The
+ * waitqueue is woken up after the timer callback function has
+ * finished execution.
+ */
+void hrtimer_wait_for_timer(const struct hrtimer *timer)
+{
+	struct hrtimer_clock_base *base = timer->base;
+
+	if (base && base->cpu_base && !timer->irqsafe)
+		wait_event(base->cpu_base->wait,
+			   !(timer->state & HRTIMER_STATE_CALLBACK));
+}
+
+#else
+# define wake_up_timer_waiters(b)	do { } while (0)
+#endif
+
 /*
  * enqueue_hrtimer - internal function to (re)start a timer
  *
@@ -889,6 +932,11 @@ static void __remove_hrtimer(struct hrti
 	if (!(timer->state & HRTIMER_STATE_ENQUEUED))
 		goto out;
 
+	if (unlikely(!list_empty(&timer->cb_entry))) {
+		list_del_init(&timer->cb_entry);
+		goto out;
+	}
+
 	next_timer = timerqueue_getnext(&base->active);
 	timerqueue_del(&base->active, &timer->node);
 	if (&timer->node == next_timer) {
@@ -985,8 +1033,20 @@ int __hrtimer_start_range_ns(struct hrti
 	 *
 	 * XXX send_remote_softirq() ?
 	 */
-	if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases))
-		hrtimer_enqueue_reprogram(timer, new_base, wakeup);
+	if (leftmost && new_base->cpu_base == &__get_cpu_var(hrtimer_bases)) {
+		ret = hrtimer_enqueue_reprogram(timer, new_base, wakeup);
+		if (ret) {
+			/*
+			 * In case we failed to reprogram the timer (mostly
+			 * because out current timer is already elapsed),
+			 * remove it again and report a failure. This avoids
+			 * stale base->first entries.
+			 */
+			debug_deactivate(timer);
+			__remove_hrtimer(timer, new_base,
+					timer->state & HRTIMER_STATE_CALLBACK, 0);
+		}
+	}
 
 	unlock_hrtimer_base(timer, &flags);
 
@@ -1072,7 +1132,7 @@ int hrtimer_cancel(struct hrtimer *timer
 
 		if (ret >= 0)
 			return ret;
-		cpu_relax();
+		hrtimer_wait_for_timer(timer);
 	}
 }
 EXPORT_SYMBOL_GPL(hrtimer_cancel);
@@ -1151,6 +1211,7 @@ static void __hrtimer_init(struct hrtime
 
 	base = hrtimer_clockid_to_base(clock_id);
 	timer->base = &cpu_base->clock_base[base];
+	INIT_LIST_HEAD(&timer->cb_entry);
 	timerqueue_init(&timer->node);
 
 #ifdef CONFIG_TIMER_STATS
@@ -1234,6 +1295,122 @@ static void __run_hrtimer(struct hrtimer
 	timer->state &= ~HRTIMER_STATE_CALLBACK;
 }
 
+static enum hrtimer_restart hrtimer_wakeup(struct hrtimer *timer);
+
+#ifdef CONFIG_PREEMPT_RT_BASE
+static void hrtimer_rt_reprogram(int restart, struct hrtimer *timer,
+				 struct hrtimer_clock_base *base)
+{
+	/*
+	 * Note, we clear the callback flag before we requeue the
+	 * timer otherwise we trigger the callback_running() check
+	 * in hrtimer_reprogram().
+	 */
+	timer->state &= ~HRTIMER_STATE_CALLBACK;
+
+	if (restart != HRTIMER_NORESTART) {
+		BUG_ON(hrtimer_active(timer));
+		/*
+		 * Enqueue the timer, if it's the leftmost timer then
+		 * we need to reprogram it.
+		 */
+		if (!enqueue_hrtimer(timer, base))
+			return;
+
+#ifndef CONFIG_HIGH_RES_TIMERS
+	}
+#else
+		if (base->cpu_base->hres_active &&
+		    hrtimer_reprogram(timer, base))
+			goto requeue;
+
+	} else if (hrtimer_active(timer)) {
+		/*
+		 * If the timer was rearmed on another CPU, reprogram
+		 * the event device.
+		 */
+		if (&timer->node == base->active.next &&
+		    base->cpu_base->hres_active &&
+		    hrtimer_reprogram(timer, base))
+			goto requeue;
+	}
+	return;
+
+requeue:
+	/*
+	 * Timer is expired. Thus move it from tree to pending list
+	 * again.
+	 */
+	__remove_hrtimer(timer, base, timer->state, 0);
+	list_add_tail(&timer->cb_entry, &base->expired);
+#endif
+}
+
+/*
+ * The changes in mainline which removed the callback modes from
+ * hrtimer are not yet working with -rt. The non wakeup_process()
+ * based callbacks which involve sleeping locks need to be treated
+ * seperately.
+ */
+static void hrtimer_rt_run_pending(void)
+{
+	enum hrtimer_restart (*fn)(struct hrtimer *);
+	struct hrtimer_cpu_base *cpu_base;
+	struct hrtimer_clock_base *base;
+	struct hrtimer *timer;
+	int index, restart;
+
+	local_irq_disable();
+	cpu_base = &per_cpu(hrtimer_bases, smp_processor_id());
+
+	raw_spin_lock(&cpu_base->lock);
+
+	for (index = 0; index < HRTIMER_MAX_CLOCK_BASES; index++) {
+		base = &cpu_base->clock_base[index];
+
+		while (!list_empty(&base->expired)) {
+			timer = list_first_entry(&base->expired,
+						 struct hrtimer, cb_entry);
+
+			/*
+			 * Same as the above __run_hrtimer function
+			 * just we run with interrupts enabled.
+			 */
+			debug_hrtimer_deactivate(timer);
+			__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
+			timer_stats_account_hrtimer(timer);
+			fn = timer->function;
+
+			raw_spin_unlock_irq(&cpu_base->lock);
+			restart = fn(timer);
+			raw_spin_lock_irq(&cpu_base->lock);
+
+			hrtimer_rt_reprogram(restart, timer, base);
+		}
+	}
+
+	raw_spin_unlock_irq(&cpu_base->lock);
+
+	wake_up_timer_waiters(cpu_base);
+}
+
+static int hrtimer_rt_defer(struct hrtimer *timer)
+{
+	if (timer->irqsafe)
+		return 0;
+
+	__remove_hrtimer(timer, timer->base, timer->state, 0);
+	list_add_tail(&timer->cb_entry, &timer->base->expired);
+	return 1;
+}
+
+#else
+
+static inline void hrtimer_rt_run_pending(void) { }
+static inline int hrtimer_rt_defer(struct hrtimer *timer) { return 0; }
+
+#endif
+
 #ifdef CONFIG_HIGH_RES_TIMERS
 
 /*
@@ -1244,7 +1421,7 @@ void hrtimer_interrupt(struct clock_even
 {
 	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
 	ktime_t expires_next, now, entry_time, delta;
-	int i, retries = 0;
+	int i, retries = 0, raise = 0;
 
 	BUG_ON(!cpu_base->hres_active);
 	cpu_base->nr_events++;
@@ -1280,6 +1457,14 @@ retry:
 
 			timer = container_of(node, struct hrtimer, node);
 
+			trace_hrtimer_interrupt(raw_smp_processor_id(),
+			    ktime_to_ns(ktime_sub(
+				hrtimer_get_expires(timer), basenow)),
+			    current,
+			    timer->function == hrtimer_wakeup ?
+			    container_of(timer, struct hrtimer_sleeper,
+				timer)->task : NULL);
+
 			/*
 			 * The immediate goal for using the softexpires is
 			 * minimizing wakeups, not running timers at the
@@ -1303,7 +1488,10 @@ retry:
 				break;
 			}
 
-			__run_hrtimer(timer, &basenow);
+			if (!hrtimer_rt_defer(timer))
+				__run_hrtimer(timer, &basenow);
+			else
+				raise = 1;
 		}
 	}
 
@@ -1318,6 +1506,10 @@ retry:
 	if (expires_next.tv64 == KTIME_MAX ||
 	    !tick_program_event(expires_next, 0)) {
 		cpu_base->hang_detected = 0;
+
+		if (raise)
+			raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+
 		return;
 	}
 
@@ -1393,17 +1585,17 @@ void hrtimer_peek_ahead_timers(void)
 	local_irq_restore(flags);
 }
 
-static void run_hrtimer_softirq(struct softirq_action *h)
-{
-	hrtimer_peek_ahead_timers();
-}
-
 #else /* CONFIG_HIGH_RES_TIMERS */
 
 static inline void __hrtimer_peek_ahead_timers(void) { }
 
 #endif	/* !CONFIG_HIGH_RES_TIMERS */
 
+static void run_hrtimer_softirq(struct softirq_action *h)
+{
+	hrtimer_rt_run_pending();
+}
+
 /*
  * Called from timer softirq every jiffy, expire hrtimers:
  *
@@ -1436,7 +1628,7 @@ void hrtimer_run_queues(void)
 	struct timerqueue_node *node;
 	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
 	struct hrtimer_clock_base *base;
-	int index, gettime = 1;
+	int index, gettime = 1, raise = 0;
 
 	if (hrtimer_hres_active())
 		return;
@@ -1461,10 +1653,16 @@ void hrtimer_run_queues(void)
 					hrtimer_get_expires_tv64(timer))
 				break;
 
-			__run_hrtimer(timer, &base->softirq_time);
+			if (!hrtimer_rt_defer(timer))
+				__run_hrtimer(timer, &base->softirq_time);
+			else
+				raise = 1;
 		}
 		raw_spin_unlock(&cpu_base->lock);
 	}
+
+	if (raise)
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
 }
 
 /*
@@ -1486,6 +1684,7 @@ static enum hrtimer_restart hrtimer_wake
 void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, struct task_struct *task)
 {
 	sl->timer.function = hrtimer_wakeup;
+	sl->timer.irqsafe = 1;
 	sl->task = task;
 }
 EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
@@ -1624,9 +1823,13 @@ static void __cpuinit init_hrtimers_cpu(
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 		cpu_base->clock_base[i].cpu_base = cpu_base;
 		timerqueue_init_head(&cpu_base->clock_base[i].active);
+		INIT_LIST_HEAD(&cpu_base->clock_base[i].expired);
 	}
 
 	hrtimer_init_hres(cpu_base);
+#ifdef CONFIG_PREEMPT_RT_BASE
+	init_waitqueue_head(&cpu_base->wait);
+#endif
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1739,9 +1942,7 @@ void __init hrtimers_init(void)
 	hrtimer_cpu_notify(&hrtimers_nb, (unsigned long)CPU_UP_PREPARE,
 			  (void *)(long)smp_processor_id());
 	register_cpu_notifier(&hrtimers_nb);
-#ifdef CONFIG_HIGH_RES_TIMERS
 	open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq);
-#endif
 }
 
 /**
Index: linux-3.4/kernel/trace/Kconfig
===================================================================
--- linux-3.4.orig/kernel/trace/Kconfig
+++ linux-3.4/kernel/trace/Kconfig
@@ -192,6 +192,24 @@ config IRQSOFF_TRACER
 	  enabled. This option and the preempt-off timing option can be
 	  used together or separately.)
 
+config INTERRUPT_OFF_HIST
+	bool "Interrupts-off Latency Histogram"
+	depends on IRQSOFF_TRACER
+	help
+	  This option generates continuously updated histograms (one per cpu)
+	  of the duration of time periods with interrupts disabled. The
+	  histograms are disabled by default. To enable them, write a non-zero
+	  number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/preemptirqsoff
+
+	  If PREEMPT_OFF_HIST is also selected, additional histograms (one
+	  per cpu) are generated that accumulate the duration of time periods
+	  when both interrupts and preemption are disabled. The histogram data
+	  will be located in the debug file system at
+
+	      /sys/kernel/debug/tracing/latency_hist/irqsoff
+
 config PREEMPT_TRACER
 	bool "Preemption-off Latency Tracer"
 	default n
@@ -214,6 +232,24 @@ config PREEMPT_TRACER
 	  enabled. This option and the irqs-off timing option can be
 	  used together or separately.)
 
+config PREEMPT_OFF_HIST
+	bool "Preemption-off Latency Histogram"
+	depends on PREEMPT_TRACER
+	help
+	  This option generates continuously updated histograms (one per cpu)
+	  of the duration of time periods with preemption disabled. The
+	  histograms are disabled by default. To enable them, write a non-zero
+	  number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/preemptirqsoff
+
+	  If INTERRUPT_OFF_HIST is also selected, additional histograms (one
+	  per cpu) are generated that accumulate the duration of time periods
+	  when both interrupts and preemption are disabled. The histogram data
+	  will be located in the debug file system at
+
+	      /sys/kernel/debug/tracing/latency_hist/preemptoff
+
 config SCHED_TRACER
 	bool "Scheduling Latency Tracer"
 	select GENERIC_TRACER
@@ -223,6 +259,74 @@ config SCHED_TRACER
 	  This tracer tracks the latency of the highest priority task
 	  to be scheduled in, starting from the point it has woken up.
 
+config WAKEUP_LATENCY_HIST
+	bool "Scheduling Latency Histogram"
+	depends on SCHED_TRACER
+	help
+	  This option generates continuously updated histograms (one per cpu)
+	  of the scheduling latency of the highest priority task.
+	  The histograms are disabled by default. To enable them, write a
+	  non-zero number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/wakeup
+
+	  Two different algorithms are used, one to determine the latency of
+	  processes that exclusively use the highest priority of the system and
+	  another one to determine the latency of processes that share the
+	  highest system priority with other processes. The former is used to
+	  improve hardware and system software, the latter to optimize the
+	  priority design of a given system. The histogram data will be
+	  located in the debug file system at
+
+	      /sys/kernel/debug/tracing/latency_hist/wakeup
+
+	  and
+
+	      /sys/kernel/debug/tracing/latency_hist/wakeup/sharedprio
+
+	  If both Scheduling Latency Histogram and Missed Timer Offsets
+	  Histogram are selected, additional histogram data will be collected
+	  that contain, in addition to the wakeup latency, the timer latency, in
+	  case the wakeup was triggered by an expired timer. These histograms
+	  are available in the
+
+	      /sys/kernel/debug/tracing/latency_hist/timerandwakeup
+
+	  directory. They reflect the apparent interrupt and scheduling latency
+	  and are best suitable to determine the worst-case latency of a given
+	  system. To enable these histograms, write a non-zero number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/timerandwakeup
+
+config MISSED_TIMER_OFFSETS_HIST
+	depends on HIGH_RES_TIMERS
+	select GENERIC_TRACER
+	bool "Missed Timer Offsets Histogram"
+	help
+	  Generate a histogram of missed timer offsets in microseconds. The
+	  histograms are disabled by default. To enable them, write a non-zero
+	  number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/missed_timer_offsets
+
+	  The histogram data will be located in the debug file system at
+
+	      /sys/kernel/debug/tracing/latency_hist/missed_timer_offsets
+
+	  If both Scheduling Latency Histogram and Missed Timer Offsets
+	  Histogram are selected, additional histogram data will be collected
+	  that contain, in addition to the wakeup latency, the timer latency, in
+	  case the wakeup was triggered by an expired timer. These histograms
+	  are available in the
+
+	      /sys/kernel/debug/tracing/latency_hist/timerandwakeup
+
+	  directory. They reflect the apparent interrupt and scheduling latency
+	  and are best suitable to determine the worst-case latency of a given
+	  system. To enable these histograms, write a non-zero number to
+
+	      /sys/kernel/debug/tracing/latency_hist/enable/timerandwakeup
+
 config ENABLE_DEFAULT_TRACERS
 	bool "Trace process context switches and events"
 	depends on !GENERIC_TRACER
Index: linux-3.4/kernel/trace/Makefile
===================================================================
--- linux-3.4.orig/kernel/trace/Makefile
+++ linux-3.4/kernel/trace/Makefile
@@ -36,6 +36,10 @@ obj-$(CONFIG_FUNCTION_TRACER) += trace_f
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
+obj-$(CONFIG_INTERRUPT_OFF_HIST) += latency_hist.o
+obj-$(CONFIG_PREEMPT_OFF_HIST) += latency_hist.o
+obj-$(CONFIG_WAKEUP_LATENCY_HIST) += latency_hist.o
+obj-$(CONFIG_MISSED_TIMER_OFFSETS_HIST) += latency_hist.o
 obj-$(CONFIG_NOP_TRACER) += trace_nop.o
 obj-$(CONFIG_STACK_TRACER) += trace_stack.o
 obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
Index: linux-3.4/kernel/trace/latency_hist.c
===================================================================
--- /dev/null
+++ linux-3.4/kernel/trace/latency_hist.c
@@ -0,0 +1,1170 @@
+/*
+ * kernel/trace/latency_hist.c
+ *
+ * Add support for histograms of preemption-off latency and
+ * interrupt-off latency and wakeup latency, it depends on
+ * Real-Time Preemption Support.
+ *
+ *  Copyright (C) 2005 MontaVista Software, Inc.
+ *  Yi Yang <yyang@ch.mvista.com>
+ *
+ *  Converted to work with the new latency tracer.
+ *  Copyright (C) 2008 Red Hat, Inc.
+ *    Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/percpu.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <asm/atomic.h>
+#include <asm/div64.h>
+
+#include "trace.h"
+#include <trace/events/sched.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/hist.h>
+
+enum {
+	IRQSOFF_LATENCY = 0,
+	PREEMPTOFF_LATENCY,
+	PREEMPTIRQSOFF_LATENCY,
+	WAKEUP_LATENCY,
+	WAKEUP_LATENCY_SHAREDPRIO,
+	MISSED_TIMER_OFFSETS,
+	TIMERANDWAKEUP_LATENCY,
+	MAX_LATENCY_TYPE,
+};
+
+#define MAX_ENTRY_NUM 10240
+
+struct hist_data {
+	atomic_t hist_mode; /* 0 log, 1 don't log */
+	long offset; /* set it to MAX_ENTRY_NUM/2 for a bipolar scale */
+	unsigned long min_lat;
+	unsigned long max_lat;
+	unsigned long long below_hist_bound_samples;
+	unsigned long long above_hist_bound_samples;
+	unsigned long long accumulate_lat;
+	unsigned long long total_samples;
+	unsigned long long hist_array[MAX_ENTRY_NUM];
+};
+
+struct enable_data {
+	int latency_type;
+	int enabled;
+};
+
+static char *latency_hist_dir_root = "latency_hist";
+
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+static DEFINE_PER_CPU(struct hist_data, irqsoff_hist);
+static char *irqsoff_hist_dir = "irqsoff";
+static DEFINE_PER_CPU(cycles_t, hist_irqsoff_start);
+static DEFINE_PER_CPU(int, hist_irqsoff_counting);
+#endif
+
+#ifdef CONFIG_PREEMPT_OFF_HIST
+static DEFINE_PER_CPU(struct hist_data, preemptoff_hist);
+static char *preemptoff_hist_dir = "preemptoff";
+static DEFINE_PER_CPU(cycles_t, hist_preemptoff_start);
+static DEFINE_PER_CPU(int, hist_preemptoff_counting);
+#endif
+
+#if defined(CONFIG_PREEMPT_OFF_HIST) && defined(CONFIG_INTERRUPT_OFF_HIST)
+static DEFINE_PER_CPU(struct hist_data, preemptirqsoff_hist);
+static char *preemptirqsoff_hist_dir = "preemptirqsoff";
+static DEFINE_PER_CPU(cycles_t, hist_preemptirqsoff_start);
+static DEFINE_PER_CPU(int, hist_preemptirqsoff_counting);
+#endif
+
+#if defined(CONFIG_PREEMPT_OFF_HIST) || defined(CONFIG_INTERRUPT_OFF_HIST)
+static notrace void probe_preemptirqsoff_hist(void *v, int reason, int start);
+static struct enable_data preemptirqsoff_enabled_data = {
+	.latency_type = PREEMPTIRQSOFF_LATENCY,
+	.enabled = 0,
+};
+#endif
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+struct maxlatproc_data {
+	char comm[FIELD_SIZEOF(struct task_struct, comm)];
+	char current_comm[FIELD_SIZEOF(struct task_struct, comm)];
+	int pid;
+	int current_pid;
+	int prio;
+	int current_prio;
+	long latency;
+	long timeroffset;
+	cycle_t timestamp;
+};
+#endif
+
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+static DEFINE_PER_CPU(struct hist_data, wakeup_latency_hist);
+static DEFINE_PER_CPU(struct hist_data, wakeup_latency_hist_sharedprio);
+static char *wakeup_latency_hist_dir = "wakeup";
+static char *wakeup_latency_hist_dir_sharedprio = "sharedprio";
+static notrace void probe_wakeup_latency_hist_start(void *v,
+    struct task_struct *p, int success);
+static notrace void probe_wakeup_latency_hist_stop(void *v,
+    struct task_struct *prev, struct task_struct *next);
+static notrace void probe_sched_migrate_task(void *,
+    struct task_struct *task, int cpu);
+static struct enable_data wakeup_latency_enabled_data = {
+	.latency_type = WAKEUP_LATENCY,
+	.enabled = 0,
+};
+static DEFINE_PER_CPU(struct maxlatproc_data, wakeup_maxlatproc);
+static DEFINE_PER_CPU(struct maxlatproc_data, wakeup_maxlatproc_sharedprio);
+static DEFINE_PER_CPU(struct task_struct *, wakeup_task);
+static DEFINE_PER_CPU(int, wakeup_sharedprio);
+static unsigned long wakeup_pid;
+#endif
+
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+static DEFINE_PER_CPU(struct hist_data, missed_timer_offsets);
+static char *missed_timer_offsets_dir = "missed_timer_offsets";
+static notrace void probe_hrtimer_interrupt(void *v, int cpu,
+    long long offset, struct task_struct *curr, struct task_struct *task);
+static struct enable_data missed_timer_offsets_enabled_data = {
+	.latency_type = MISSED_TIMER_OFFSETS,
+	.enabled = 0,
+};
+static DEFINE_PER_CPU(struct maxlatproc_data, missed_timer_offsets_maxlatproc);
+static unsigned long missed_timer_offsets_pid;
+#endif
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+static DEFINE_PER_CPU(struct hist_data, timerandwakeup_latency_hist);
+static char *timerandwakeup_latency_hist_dir = "timerandwakeup";
+static struct enable_data timerandwakeup_enabled_data = {
+	.latency_type = TIMERANDWAKEUP_LATENCY,
+	.enabled = 0,
+};
+static DEFINE_PER_CPU(struct maxlatproc_data, timerandwakeup_maxlatproc);
+#endif
+
+void notrace latency_hist(int latency_type, int cpu, unsigned long latency,
+			  unsigned long timeroffset, cycle_t stop,
+			  struct task_struct *p)
+{
+	struct hist_data *my_hist;
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+	struct maxlatproc_data *mp = NULL;
+#endif
+
+	if (cpu < 0 || cpu >= NR_CPUS || latency_type < 0 ||
+	    latency_type >= MAX_LATENCY_TYPE)
+		return;
+
+	switch (latency_type) {
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+	case IRQSOFF_LATENCY:
+		my_hist = &per_cpu(irqsoff_hist, cpu);
+		break;
+#endif
+#ifdef CONFIG_PREEMPT_OFF_HIST
+	case PREEMPTOFF_LATENCY:
+		my_hist = &per_cpu(preemptoff_hist, cpu);
+		break;
+#endif
+#if defined(CONFIG_PREEMPT_OFF_HIST) && defined(CONFIG_INTERRUPT_OFF_HIST)
+	case PREEMPTIRQSOFF_LATENCY:
+		my_hist = &per_cpu(preemptirqsoff_hist, cpu);
+		break;
+#endif
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+	case WAKEUP_LATENCY:
+		my_hist = &per_cpu(wakeup_latency_hist, cpu);
+		mp = &per_cpu(wakeup_maxlatproc, cpu);
+		break;
+	case WAKEUP_LATENCY_SHAREDPRIO:
+		my_hist = &per_cpu(wakeup_latency_hist_sharedprio, cpu);
+		mp = &per_cpu(wakeup_maxlatproc_sharedprio, cpu);
+		break;
+#endif
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+	case MISSED_TIMER_OFFSETS:
+		my_hist = &per_cpu(missed_timer_offsets, cpu);
+		mp = &per_cpu(missed_timer_offsets_maxlatproc, cpu);
+		break;
+#endif
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+	case TIMERANDWAKEUP_LATENCY:
+		my_hist = &per_cpu(timerandwakeup_latency_hist, cpu);
+		mp = &per_cpu(timerandwakeup_maxlatproc, cpu);
+		break;
+#endif
+
+	default:
+		return;
+	}
+
+	latency += my_hist->offset;
+
+	if (atomic_read(&my_hist->hist_mode) == 0)
+		return;
+
+	if (latency < 0 || latency >= MAX_ENTRY_NUM) {
+		if (latency < 0)
+			my_hist->below_hist_bound_samples++;
+		else
+			my_hist->above_hist_bound_samples++;
+	} else
+		my_hist->hist_array[latency]++;
+
+	if (unlikely(latency > my_hist->max_lat ||
+	    my_hist->min_lat == ULONG_MAX)) {
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+		if (latency_type == WAKEUP_LATENCY ||
+		    latency_type == WAKEUP_LATENCY_SHAREDPRIO ||
+		    latency_type == MISSED_TIMER_OFFSETS ||
+		    latency_type == TIMERANDWAKEUP_LATENCY) {
+			strncpy(mp->comm, p->comm, sizeof(mp->comm));
+			strncpy(mp->current_comm, current->comm,
+			    sizeof(mp->current_comm));
+			mp->pid = task_pid_nr(p);
+			mp->current_pid = task_pid_nr(current);
+			mp->prio = p->prio;
+			mp->current_prio = current->prio;
+			mp->latency = latency;
+			mp->timeroffset = timeroffset;
+			mp->timestamp = stop;
+		}
+#endif
+		my_hist->max_lat = latency;
+	}
+	if (unlikely(latency < my_hist->min_lat))
+		my_hist->min_lat = latency;
+	my_hist->total_samples++;
+	my_hist->accumulate_lat += latency;
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+	loff_t *index_ptr = NULL;
+	loff_t index = *pos;
+	struct hist_data *my_hist = m->private;
+
+	if (index == 0) {
+		char minstr[32], avgstr[32], maxstr[32];
+
+		atomic_dec(&my_hist->hist_mode);
+
+		if (likely(my_hist->total_samples)) {
+			unsigned long avg = (unsigned long)
+			    div64_u64(my_hist->accumulate_lat,
+			    my_hist->total_samples);
+			snprintf(minstr, sizeof(minstr), "%ld",
+			    (long) my_hist->min_lat - my_hist->offset);
+			snprintf(avgstr, sizeof(avgstr), "%ld",
+			    (long) avg - my_hist->offset);
+			snprintf(maxstr, sizeof(maxstr), "%ld",
+			    (long) my_hist->max_lat - my_hist->offset);
+		} else {
+			strcpy(minstr, "<undef>");
+			strcpy(avgstr, minstr);
+			strcpy(maxstr, minstr);
+		}
+
+		seq_printf(m, "#Minimum latency: %s microseconds\n"
+			   "#Average latency: %s microseconds\n"
+			   "#Maximum latency: %s microseconds\n"
+			   "#Total samples: %llu\n"
+			   "#There are %llu samples lower than %ld"
+			   " microseconds.\n"
+			   "#There are %llu samples greater or equal"
+			   " than %ld microseconds.\n"
+			   "#usecs\t%16s\n",
+			   minstr, avgstr, maxstr,
+			   my_hist->total_samples,
+			   my_hist->below_hist_bound_samples,
+			   -my_hist->offset,
+			   my_hist->above_hist_bound_samples,
+			   MAX_ENTRY_NUM - my_hist->offset,
+			   "samples");
+	}
+	if (index < MAX_ENTRY_NUM) {
+		index_ptr = kmalloc(sizeof(loff_t), GFP_KERNEL);
+		if (index_ptr)
+			*index_ptr = index;
+	}
+
+	return index_ptr;
+}
+
+static void *l_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	loff_t *index_ptr = p;
+	struct hist_data *my_hist = m->private;
+
+	if (++*pos >= MAX_ENTRY_NUM) {
+		atomic_inc(&my_hist->hist_mode);
+		return NULL;
+	}
+	*index_ptr = *pos;
+	return index_ptr;
+}
+
+static void l_stop(struct seq_file *m, void *p)
+{
+	kfree(p);
+}
+
+static int l_show(struct seq_file *m, void *p)
+{
+	int index = *(loff_t *) p;
+	struct hist_data *my_hist = m->private;
+
+	seq_printf(m, "%6ld\t%16llu\n", index - my_hist->offset,
+	    my_hist->hist_array[index]);
+	return 0;
+}
+
+static struct seq_operations latency_hist_seq_op = {
+	.start = l_start,
+	.next  = l_next,
+	.stop  = l_stop,
+	.show  = l_show
+};
+
+static int latency_hist_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	ret = seq_open(file, &latency_hist_seq_op);
+	if (!ret) {
+		struct seq_file *seq = file->private_data;
+		seq->private = inode->i_private;
+	}
+	return ret;
+}
+
+static struct file_operations latency_hist_fops = {
+	.open = latency_hist_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+static void clear_maxlatprocdata(struct maxlatproc_data *mp)
+{
+	mp->comm[0] = mp->current_comm[0] = '\0';
+	mp->prio = mp->current_prio = mp->pid = mp->current_pid =
+	    mp->latency = mp->timeroffset = -1;
+	mp->timestamp = 0;
+}
+#endif
+
+static void hist_reset(struct hist_data *hist)
+{
+	atomic_dec(&hist->hist_mode);
+
+	memset(hist->hist_array, 0, sizeof(hist->hist_array));
+	hist->below_hist_bound_samples = 0ULL;
+	hist->above_hist_bound_samples = 0ULL;
+	hist->min_lat = ULONG_MAX;
+	hist->max_lat = 0UL;
+	hist->total_samples = 0ULL;
+	hist->accumulate_lat = 0ULL;
+
+	atomic_inc(&hist->hist_mode);
+}
+
+static ssize_t
+latency_hist_reset(struct file *file, const char __user *a,
+		   size_t size, loff_t *off)
+{
+	int cpu;
+	struct hist_data *hist = NULL;
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+	struct maxlatproc_data *mp = NULL;
+#endif
+	off_t latency_type = (off_t) file->private_data;
+
+	for_each_online_cpu(cpu) {
+
+		switch (latency_type) {
+#ifdef CONFIG_PREEMPT_OFF_HIST
+		case PREEMPTOFF_LATENCY:
+			hist = &per_cpu(preemptoff_hist, cpu);
+			break;
+#endif
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+		case IRQSOFF_LATENCY:
+			hist = &per_cpu(irqsoff_hist, cpu);
+			break;
+#endif
+#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
+		case PREEMPTIRQSOFF_LATENCY:
+			hist = &per_cpu(preemptirqsoff_hist, cpu);
+			break;
+#endif
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+		case WAKEUP_LATENCY:
+			hist = &per_cpu(wakeup_latency_hist, cpu);
+			mp = &per_cpu(wakeup_maxlatproc, cpu);
+			break;
+		case WAKEUP_LATENCY_SHAREDPRIO:
+			hist = &per_cpu(wakeup_latency_hist_sharedprio, cpu);
+			mp = &per_cpu(wakeup_maxlatproc_sharedprio, cpu);
+			break;
+#endif
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+		case MISSED_TIMER_OFFSETS:
+			hist = &per_cpu(missed_timer_offsets, cpu);
+			mp = &per_cpu(missed_timer_offsets_maxlatproc, cpu);
+			break;
+#endif
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+		case TIMERANDWAKEUP_LATENCY:
+			hist = &per_cpu(timerandwakeup_latency_hist, cpu);
+			mp = &per_cpu(timerandwakeup_maxlatproc, cpu);
+			break;
+#endif
+		}
+
+		hist_reset(hist);
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+		if (latency_type == WAKEUP_LATENCY ||
+		    latency_type == WAKEUP_LATENCY_SHAREDPRIO ||
+		    latency_type == MISSED_TIMER_OFFSETS ||
+		    latency_type == TIMERANDWAKEUP_LATENCY)
+			clear_maxlatprocdata(mp);
+#endif
+	}
+
+	return size;
+}
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+static ssize_t
+show_pid(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+	unsigned long *this_pid = file->private_data;
+
+	r = snprintf(buf, sizeof(buf), "%lu\n", *this_pid);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t do_pid(struct file *file, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	unsigned long pid;
+	unsigned long *this_pid = file->private_data;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = '\0';
+
+	if (strict_strtoul(buf, 10, &pid))
+		return(-EINVAL);
+
+	*this_pid = pid;
+
+	return cnt;
+}
+#endif
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+static ssize_t
+show_maxlatproc(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	int r;
+	struct maxlatproc_data *mp = file->private_data;
+	int strmaxlen = (TASK_COMM_LEN * 2) + (8 * 8);
+	unsigned long long t;
+	unsigned long usecs, secs;
+	char *buf;
+
+	if (mp->pid == -1 || mp->current_pid == -1) {
+		buf = "(none)\n";
+		return simple_read_from_buffer(ubuf, cnt, ppos, buf,
+		    strlen(buf));
+	}
+
+	buf = kmalloc(strmaxlen, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	t = ns2usecs(mp->timestamp);
+	usecs = do_div(t, USEC_PER_SEC);
+	secs = (unsigned long) t;
+	r = snprintf(buf, strmaxlen,
+	    "%d %d %ld (%ld) %s <- %d %d %s %lu.%06lu\n", mp->pid,
+	    MAX_RT_PRIO-1 - mp->prio, mp->latency, mp->timeroffset, mp->comm,
+	    mp->current_pid, MAX_RT_PRIO-1 - mp->current_prio, mp->current_comm,
+	    secs, usecs);
+	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+	kfree(buf);
+	return r;
+}
+#endif
+
+static ssize_t
+show_enable(struct file *file, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	struct enable_data *ed = file->private_data;
+	int r;
+
+	r = snprintf(buf, sizeof(buf), "%d\n", ed->enabled);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+do_enable(struct file *file, const char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	long enable;
+	struct enable_data *ed = file->private_data;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	if (strict_strtol(buf, 10, &enable))
+		return(-EINVAL);
+
+	if ((enable && ed->enabled) || (!enable && !ed->enabled))
+		return cnt;
+
+	if (enable) {
+		int ret;
+
+		switch (ed->latency_type) {
+#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
+		case PREEMPTIRQSOFF_LATENCY:
+			ret = register_trace_preemptirqsoff_hist(
+			    probe_preemptirqsoff_hist, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_preemptirqsoff_hist "
+				    "to trace_preemptirqsoff_hist\n");
+				return ret;
+			}
+			break;
+#endif
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+		case WAKEUP_LATENCY:
+			ret = register_trace_sched_wakeup(
+			    probe_wakeup_latency_hist_start, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_wakeup_latency_hist_start "
+				    "to trace_sched_wakeup\n");
+				return ret;
+			}
+			ret = register_trace_sched_wakeup_new(
+			    probe_wakeup_latency_hist_start, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_wakeup_latency_hist_start "
+				    "to trace_sched_wakeup_new\n");
+				unregister_trace_sched_wakeup(
+				    probe_wakeup_latency_hist_start, NULL);
+				return ret;
+			}
+			ret = register_trace_sched_switch(
+			    probe_wakeup_latency_hist_stop, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_wakeup_latency_hist_stop "
+				    "to trace_sched_switch\n");
+				unregister_trace_sched_wakeup(
+				    probe_wakeup_latency_hist_start, NULL);
+				unregister_trace_sched_wakeup_new(
+				    probe_wakeup_latency_hist_start, NULL);
+				return ret;
+			}
+			ret = register_trace_sched_migrate_task(
+			    probe_sched_migrate_task, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_sched_migrate_task "
+				    "to trace_sched_migrate_task\n");
+				unregister_trace_sched_wakeup(
+				    probe_wakeup_latency_hist_start, NULL);
+				unregister_trace_sched_wakeup_new(
+				    probe_wakeup_latency_hist_start, NULL);
+				unregister_trace_sched_switch(
+				    probe_wakeup_latency_hist_stop, NULL);
+				return ret;
+			}
+			break;
+#endif
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+		case MISSED_TIMER_OFFSETS:
+			ret = register_trace_hrtimer_interrupt(
+			    probe_hrtimer_interrupt, NULL);
+			if (ret) {
+				pr_info("wakeup trace: Couldn't assign "
+				    "probe_hrtimer_interrupt "
+				    "to trace_hrtimer_interrupt\n");
+				return ret;
+			}
+			break;
+#endif
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+		case TIMERANDWAKEUP_LATENCY:
+			if (!wakeup_latency_enabled_data.enabled ||
+			    !missed_timer_offsets_enabled_data.enabled)
+				return -EINVAL;
+			break;
+#endif
+		default:
+			break;
+		}
+	} else {
+		switch (ed->latency_type) {
+#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
+		case PREEMPTIRQSOFF_LATENCY:
+			{
+				int cpu;
+
+				unregister_trace_preemptirqsoff_hist(
+				    probe_preemptirqsoff_hist, NULL);
+				for_each_online_cpu(cpu) {
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+					per_cpu(hist_irqsoff_counting,
+					    cpu) = 0;
+#endif
+#ifdef CONFIG_PREEMPT_OFF_HIST
+					per_cpu(hist_preemptoff_counting,
+					    cpu) = 0;
+#endif
+#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
+					per_cpu(hist_preemptirqsoff_counting,
+					    cpu) = 0;
+#endif
+				}
+			}
+			break;
+#endif
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+		case WAKEUP_LATENCY:
+			{
+				int cpu;
+
+				unregister_trace_sched_wakeup(
+				    probe_wakeup_latency_hist_start, NULL);
+				unregister_trace_sched_wakeup_new(
+				    probe_wakeup_latency_hist_start, NULL);
+				unregister_trace_sched_switch(
+				    probe_wakeup_latency_hist_stop, NULL);
+				unregister_trace_sched_migrate_task(
+				    probe_sched_migrate_task, NULL);
+
+				for_each_online_cpu(cpu) {
+					per_cpu(wakeup_task, cpu) = NULL;
+					per_cpu(wakeup_sharedprio, cpu) = 0;
+				}
+			}
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+			timerandwakeup_enabled_data.enabled = 0;
+#endif
+			break;
+#endif
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+		case MISSED_TIMER_OFFSETS:
+			unregister_trace_hrtimer_interrupt(
+			    probe_hrtimer_interrupt, NULL);
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+			timerandwakeup_enabled_data.enabled = 0;
+#endif
+			break;
+#endif
+		default:
+			break;
+		}
+	}
+	ed->enabled = enable;
+	return cnt;
+}
+
+static const struct file_operations latency_hist_reset_fops = {
+	.open = tracing_open_generic,
+	.write = latency_hist_reset,
+};
+
+static const struct file_operations enable_fops = {
+	.open = tracing_open_generic,
+	.read = show_enable,
+	.write = do_enable,
+};
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+static const struct file_operations pid_fops = {
+	.open = tracing_open_generic,
+	.read = show_pid,
+	.write = do_pid,
+};
+
+static const struct file_operations maxlatproc_fops = {
+	.open = tracing_open_generic,
+	.read = show_maxlatproc,
+};
+#endif
+
+#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
+static notrace void probe_preemptirqsoff_hist(void *v, int reason,
+    int starthist)
+{
+	int cpu = raw_smp_processor_id();
+	int time_set = 0;
+
+	if (starthist) {
+		cycle_t uninitialized_var(start);
+
+		if (!preempt_count() && !irqs_disabled())
+			return;
+
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+		if ((reason == IRQS_OFF || reason == TRACE_START) &&
+		    !per_cpu(hist_irqsoff_counting, cpu)) {
+			per_cpu(hist_irqsoff_counting, cpu) = 1;
+			start = ftrace_now(cpu);
+			time_set++;
+			per_cpu(hist_irqsoff_start, cpu) = start;
+		}
+#endif
+
+#ifdef CONFIG_PREEMPT_OFF_HIST
+		if ((reason == PREEMPT_OFF || reason == TRACE_START) &&
+		    !per_cpu(hist_preemptoff_counting, cpu)) {
+			per_cpu(hist_preemptoff_counting, cpu) = 1;
+			if (!(time_set++))
+				start = ftrace_now(cpu);
+			per_cpu(hist_preemptoff_start, cpu) = start;
+		}
+#endif
+
+#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
+		if (per_cpu(hist_irqsoff_counting, cpu) &&
+		    per_cpu(hist_preemptoff_counting, cpu) &&
+		    !per_cpu(hist_preemptirqsoff_counting, cpu)) {
+			per_cpu(hist_preemptirqsoff_counting, cpu) = 1;
+			if (!time_set)
+				start = ftrace_now(cpu);
+			per_cpu(hist_preemptirqsoff_start, cpu) = start;
+		}
+#endif
+	} else {
+		cycle_t uninitialized_var(stop);
+
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+		if ((reason == IRQS_ON || reason == TRACE_STOP) &&
+		    per_cpu(hist_irqsoff_counting, cpu)) {
+			cycle_t start = per_cpu(hist_irqsoff_start, cpu);
+
+			stop = ftrace_now(cpu);
+			time_set++;
+			if (start && stop >= start) {
+				unsigned long latency =
+				    nsecs_to_usecs(stop - start);
+
+				latency_hist(IRQSOFF_LATENCY, cpu, latency, 0,
+				    stop, NULL);
+			}
+			per_cpu(hist_irqsoff_counting, cpu) = 0;
+		}
+#endif
+
+#ifdef CONFIG_PREEMPT_OFF_HIST
+		if ((reason == PREEMPT_ON || reason == TRACE_STOP) &&
+		    per_cpu(hist_preemptoff_counting, cpu)) {
+			cycle_t start = per_cpu(hist_preemptoff_start, cpu);
+
+			if (!(time_set++))
+				stop = ftrace_now(cpu);
+			if (start && stop >= start) {
+				unsigned long latency =
+				    nsecs_to_usecs(stop - start);
+
+				latency_hist(PREEMPTOFF_LATENCY, cpu, latency,
+				    0, stop, NULL);
+			}
+			per_cpu(hist_preemptoff_counting, cpu) = 0;
+		}
+#endif
+
+#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
+		if ((!per_cpu(hist_irqsoff_counting, cpu) ||
+		     !per_cpu(hist_preemptoff_counting, cpu)) &&
+		   per_cpu(hist_preemptirqsoff_counting, cpu)) {
+			cycle_t start = per_cpu(hist_preemptirqsoff_start, cpu);
+
+			if (!time_set)
+				stop = ftrace_now(cpu);
+			if (start && stop >= start) {
+				unsigned long latency =
+				    nsecs_to_usecs(stop - start);
+				latency_hist(PREEMPTIRQSOFF_LATENCY, cpu,
+				    latency, 0, stop, NULL);
+			}
+			per_cpu(hist_preemptirqsoff_counting, cpu) = 0;
+		}
+#endif
+	}
+}
+#endif
+
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+static DEFINE_RAW_SPINLOCK(wakeup_lock);
+static notrace void probe_sched_migrate_task(void *v, struct task_struct *task,
+    int cpu)
+{
+	int old_cpu = task_cpu(task);
+
+	if (cpu != old_cpu) {
+		unsigned long flags;
+		struct task_struct *cpu_wakeup_task;
+
+		raw_spin_lock_irqsave(&wakeup_lock, flags);
+
+		cpu_wakeup_task = per_cpu(wakeup_task, old_cpu);
+		if (task == cpu_wakeup_task) {
+			put_task_struct(cpu_wakeup_task);
+			per_cpu(wakeup_task, old_cpu) = NULL;
+			cpu_wakeup_task = per_cpu(wakeup_task, cpu) = task;
+			get_task_struct(cpu_wakeup_task);
+		}
+
+		raw_spin_unlock_irqrestore(&wakeup_lock, flags);
+	}
+}
+
+static notrace void probe_wakeup_latency_hist_start(void *v,
+    struct task_struct *p, int success)
+{
+	unsigned long flags;
+	struct task_struct *curr = current;
+	int cpu = task_cpu(p);
+	struct task_struct *cpu_wakeup_task;
+
+	raw_spin_lock_irqsave(&wakeup_lock, flags);
+
+	cpu_wakeup_task = per_cpu(wakeup_task, cpu);
+
+	if (wakeup_pid) {
+		if ((cpu_wakeup_task && p->prio == cpu_wakeup_task->prio) ||
+		    p->prio == curr->prio)
+			per_cpu(wakeup_sharedprio, cpu) = 1;
+		if (likely(wakeup_pid != task_pid_nr(p)))
+			goto out;
+	} else {
+		if (likely(!rt_task(p)) ||
+		    (cpu_wakeup_task && p->prio > cpu_wakeup_task->prio) ||
+		    p->prio > curr->prio)
+			goto out;
+		if ((cpu_wakeup_task && p->prio == cpu_wakeup_task->prio) ||
+		    p->prio == curr->prio)
+			per_cpu(wakeup_sharedprio, cpu) = 1;
+	}
+
+	if (cpu_wakeup_task)
+		put_task_struct(cpu_wakeup_task);
+	cpu_wakeup_task = per_cpu(wakeup_task, cpu) = p;
+	get_task_struct(cpu_wakeup_task);
+	cpu_wakeup_task->preempt_timestamp_hist =
+		ftrace_now(raw_smp_processor_id());
+out:
+	raw_spin_unlock_irqrestore(&wakeup_lock, flags);
+}
+
+static notrace void probe_wakeup_latency_hist_stop(void *v,
+    struct task_struct *prev, struct task_struct *next)
+{
+	unsigned long flags;
+	int cpu = task_cpu(next);
+	unsigned long latency;
+	cycle_t stop;
+	struct task_struct *cpu_wakeup_task;
+
+	raw_spin_lock_irqsave(&wakeup_lock, flags);
+
+	cpu_wakeup_task = per_cpu(wakeup_task, cpu);
+
+	if (cpu_wakeup_task == NULL)
+		goto out;
+
+	/* Already running? */
+	if (unlikely(current == cpu_wakeup_task))
+		goto out_reset;
+
+	if (next != cpu_wakeup_task) {
+		if (next->prio < cpu_wakeup_task->prio)
+			goto out_reset;
+
+		if (next->prio == cpu_wakeup_task->prio)
+			per_cpu(wakeup_sharedprio, cpu) = 1;
+
+		goto out;
+	}
+
+	/*
+	 * The task we are waiting for is about to be switched to.
+	 * Calculate latency and store it in histogram.
+	 */
+	stop = ftrace_now(raw_smp_processor_id());
+
+	latency = nsecs_to_usecs(stop - next->preempt_timestamp_hist);
+
+	if (per_cpu(wakeup_sharedprio, cpu)) {
+		latency_hist(WAKEUP_LATENCY_SHAREDPRIO, cpu, latency, 0, stop,
+		    next);
+		per_cpu(wakeup_sharedprio, cpu) = 0;
+	} else {
+		latency_hist(WAKEUP_LATENCY, cpu, latency, 0, stop, next);
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+		if (timerandwakeup_enabled_data.enabled) {
+			latency_hist(TIMERANDWAKEUP_LATENCY, cpu,
+			    next->timer_offset + latency, next->timer_offset,
+			    stop, next);
+		}
+#endif
+	}
+
+out_reset:
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+	next->timer_offset = 0;
+#endif
+	put_task_struct(cpu_wakeup_task);
+	per_cpu(wakeup_task, cpu) = NULL;
+out:
+	raw_spin_unlock_irqrestore(&wakeup_lock, flags);
+}
+#endif
+
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+static notrace void probe_hrtimer_interrupt(void *v, int cpu,
+    long long latency_ns, struct task_struct *curr, struct task_struct *task)
+{
+	if (latency_ns <= 0 && task != NULL && rt_task(task) &&
+	    (task->prio < curr->prio ||
+	    (task->prio == curr->prio &&
+	    !cpumask_test_cpu(cpu, &task->cpus_allowed)))) {
+		unsigned long latency;
+		cycle_t now;
+
+		if (missed_timer_offsets_pid) {
+			if (likely(missed_timer_offsets_pid !=
+			    task_pid_nr(task)))
+				return;
+		}
+
+		now = ftrace_now(cpu);
+		latency = (unsigned long) div_s64(-latency_ns, 1000);
+		latency_hist(MISSED_TIMER_OFFSETS, cpu, latency, latency, now,
+		    task);
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+		task->timer_offset = latency;
+#endif
+	}
+}
+#endif
+
+static __init int latency_hist_init(void)
+{
+	struct dentry *latency_hist_root = NULL;
+	struct dentry *dentry;
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+	struct dentry *dentry_sharedprio;
+#endif
+	struct dentry *entry;
+	struct dentry *enable_root;
+	int i = 0;
+	struct hist_data *my_hist;
+	char name[64];
+	char *cpufmt = "CPU%d";
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) || \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+	char *cpufmt_maxlatproc = "max_latency-CPU%d";
+	struct maxlatproc_data *mp = NULL;
+#endif
+
+	dentry = tracing_init_dentry();
+	latency_hist_root = debugfs_create_dir(latency_hist_dir_root, dentry);
+	enable_root = debugfs_create_dir("enable", latency_hist_root);
+
+#ifdef CONFIG_INTERRUPT_OFF_HIST
+	dentry = debugfs_create_dir(irqsoff_hist_dir, latency_hist_root);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(irqsoff_hist, i), &latency_hist_fops);
+		my_hist = &per_cpu(irqsoff_hist, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+	}
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)IRQSOFF_LATENCY, &latency_hist_reset_fops);
+#endif
+
+#ifdef CONFIG_PREEMPT_OFF_HIST
+	dentry = debugfs_create_dir(preemptoff_hist_dir,
+	    latency_hist_root);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(preemptoff_hist, i), &latency_hist_fops);
+		my_hist = &per_cpu(preemptoff_hist, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+	}
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)PREEMPTOFF_LATENCY, &latency_hist_reset_fops);
+#endif
+
+#if defined(CONFIG_INTERRUPT_OFF_HIST) && defined(CONFIG_PREEMPT_OFF_HIST)
+	dentry = debugfs_create_dir(preemptirqsoff_hist_dir,
+	    latency_hist_root);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(preemptirqsoff_hist, i), &latency_hist_fops);
+		my_hist = &per_cpu(preemptirqsoff_hist, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+	}
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)PREEMPTIRQSOFF_LATENCY, &latency_hist_reset_fops);
+#endif
+
+#if defined(CONFIG_INTERRUPT_OFF_HIST) || defined(CONFIG_PREEMPT_OFF_HIST)
+	entry = debugfs_create_file("preemptirqsoff", 0644,
+	    enable_root, (void *)&preemptirqsoff_enabled_data,
+	    &enable_fops);
+#endif
+
+#ifdef CONFIG_WAKEUP_LATENCY_HIST
+	dentry = debugfs_create_dir(wakeup_latency_hist_dir,
+	    latency_hist_root);
+	dentry_sharedprio = debugfs_create_dir(
+	    wakeup_latency_hist_dir_sharedprio, dentry);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(wakeup_latency_hist, i),
+		    &latency_hist_fops);
+		my_hist = &per_cpu(wakeup_latency_hist, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+
+		entry = debugfs_create_file(name, 0444, dentry_sharedprio,
+		    &per_cpu(wakeup_latency_hist_sharedprio, i),
+		    &latency_hist_fops);
+		my_hist = &per_cpu(wakeup_latency_hist_sharedprio, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+
+		sprintf(name, cpufmt_maxlatproc, i);
+
+		mp = &per_cpu(wakeup_maxlatproc, i);
+		entry = debugfs_create_file(name, 0444, dentry, mp,
+		    &maxlatproc_fops);
+		clear_maxlatprocdata(mp);
+
+		mp = &per_cpu(wakeup_maxlatproc_sharedprio, i);
+		entry = debugfs_create_file(name, 0444, dentry_sharedprio, mp,
+		    &maxlatproc_fops);
+		clear_maxlatprocdata(mp);
+	}
+	entry = debugfs_create_file("pid", 0644, dentry,
+	    (void *)&wakeup_pid, &pid_fops);
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)WAKEUP_LATENCY, &latency_hist_reset_fops);
+	entry = debugfs_create_file("reset", 0644, dentry_sharedprio,
+	    (void *)WAKEUP_LATENCY_SHAREDPRIO, &latency_hist_reset_fops);
+	entry = debugfs_create_file("wakeup", 0644,
+	    enable_root, (void *)&wakeup_latency_enabled_data,
+	    &enable_fops);
+#endif
+
+#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
+	dentry = debugfs_create_dir(missed_timer_offsets_dir,
+	    latency_hist_root);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(missed_timer_offsets, i), &latency_hist_fops);
+		my_hist = &per_cpu(missed_timer_offsets, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+
+		sprintf(name, cpufmt_maxlatproc, i);
+		mp = &per_cpu(missed_timer_offsets_maxlatproc, i);
+		entry = debugfs_create_file(name, 0444, dentry, mp,
+		    &maxlatproc_fops);
+		clear_maxlatprocdata(mp);
+	}
+	entry = debugfs_create_file("pid", 0644, dentry,
+	    (void *)&missed_timer_offsets_pid, &pid_fops);
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)MISSED_TIMER_OFFSETS, &latency_hist_reset_fops);
+	entry = debugfs_create_file("missed_timer_offsets", 0644,
+	    enable_root, (void *)&missed_timer_offsets_enabled_data,
+	    &enable_fops);
+#endif
+
+#if defined(CONFIG_WAKEUP_LATENCY_HIST) && \
+    defined(CONFIG_MISSED_TIMER_OFFSETS_HIST)
+	dentry = debugfs_create_dir(timerandwakeup_latency_hist_dir,
+	    latency_hist_root);
+	for_each_possible_cpu(i) {
+		sprintf(name, cpufmt, i);
+		entry = debugfs_create_file(name, 0444, dentry,
+		    &per_cpu(timerandwakeup_latency_hist, i),
+		    &latency_hist_fops);
+		my_hist = &per_cpu(timerandwakeup_latency_hist, i);
+		atomic_set(&my_hist->hist_mode, 1);
+		my_hist->min_lat = 0xFFFFFFFFUL;
+
+		sprintf(name, cpufmt_maxlatproc, i);
+		mp = &per_cpu(timerandwakeup_maxlatproc, i);
+		entry = debugfs_create_file(name, 0444, dentry, mp,
+		    &maxlatproc_fops);
+		clear_maxlatprocdata(mp);
+	}
+	entry = debugfs_create_file("reset", 0644, dentry,
+	    (void *)TIMERANDWAKEUP_LATENCY, &latency_hist_reset_fops);
+	entry = debugfs_create_file("timerandwakeup", 0644,
+	    enable_root, (void *)&timerandwakeup_enabled_data,
+	    &enable_fops);
+#endif
+	return 0;
+}
+
+__initcall(latency_hist_init);
Index: linux-3.4/kernel/trace/trace_irqsoff.c
===================================================================
--- linux-3.4.orig/kernel/trace/trace_irqsoff.c
+++ linux-3.4/kernel/trace/trace_irqsoff.c
@@ -17,6 +17,7 @@
 #include <linux/fs.h>
 
 #include "trace.h"
+#include <trace/events/hist.h>
 
 static struct trace_array		*irqsoff_trace __read_mostly;
 static int				tracer_enabled __read_mostly;
@@ -437,11 +438,13 @@ void start_critical_timings(void)
 {
 	if (preempt_trace() || irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+	trace_preemptirqsoff_hist(TRACE_START, 1);
 }
 EXPORT_SYMBOL_GPL(start_critical_timings);
 
 void stop_critical_timings(void)
 {
+	trace_preemptirqsoff_hist(TRACE_STOP, 0);
 	if (preempt_trace() || irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
@@ -451,6 +454,7 @@ EXPORT_SYMBOL_GPL(stop_critical_timings)
 #ifdef CONFIG_PROVE_LOCKING
 void time_hardirqs_on(unsigned long a0, unsigned long a1)
 {
+	trace_preemptirqsoff_hist(IRQS_ON, 0);
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(a0, a1);
 }
@@ -459,6 +463,7 @@ void time_hardirqs_off(unsigned long a0,
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(a0, a1);
+	trace_preemptirqsoff_hist(IRQS_OFF, 1);
 }
 
 #else /* !CONFIG_PROVE_LOCKING */
@@ -484,6 +489,7 @@ inline void print_irqtrace_events(struct
  */
 void trace_hardirqs_on(void)
 {
+	trace_preemptirqsoff_hist(IRQS_ON, 0);
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
@@ -493,11 +499,13 @@ void trace_hardirqs_off(void)
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+	trace_preemptirqsoff_hist(IRQS_OFF, 1);
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 
 void trace_hardirqs_on_caller(unsigned long caller_addr)
 {
+	trace_preemptirqsoff_hist(IRQS_ON, 0);
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(CALLER_ADDR0, caller_addr);
 }
@@ -507,6 +515,7 @@ void trace_hardirqs_off_caller(unsigned 
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(CALLER_ADDR0, caller_addr);
+	trace_preemptirqsoff_hist(IRQS_OFF, 1);
 }
 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 
@@ -516,12 +525,14 @@ EXPORT_SYMBOL(trace_hardirqs_off_caller)
 #ifdef CONFIG_PREEMPT_TRACER
 void trace_preempt_on(unsigned long a0, unsigned long a1)
 {
+	trace_preemptirqsoff_hist(PREEMPT_ON, 0);
 	if (preempt_trace() && !irq_trace())
 		stop_critical_timing(a0, a1);
 }
 
 void trace_preempt_off(unsigned long a0, unsigned long a1)
 {
+	trace_preemptirqsoff_hist(PREEMPT_ON, 1);
 	if (preempt_trace() && !irq_trace())
 		start_critical_timing(a0, a1);
 }
Index: linux-3.4/Documentation/hwlat_detector.txt
===================================================================
--- /dev/null
+++ linux-3.4/Documentation/hwlat_detector.txt
@@ -0,0 +1,64 @@
+Introduction:
+-------------
+
+The module hwlat_detector is a special purpose kernel module that is used to
+detect large system latencies induced by the behavior of certain underlying
+hardware or firmware, independent of Linux itself. The code was developed
+originally to detect SMIs (System Management Interrupts) on x86 systems,
+however there is nothing x86 specific about this patchset. It was
+originally written for use by the "RT" patch since the Real Time
+kernel is highly latency sensitive.
+
+SMIs are usually not serviced by the Linux kernel, which typically does not
+even know that they are occuring. SMIs are instead are set up by BIOS code
+and are serviced by BIOS code, usually for "critical" events such as
+management of thermal sensors and fans. Sometimes though, SMIs are used for
+other tasks and those tasks can spend an inordinate amount of time in the
+handler (sometimes measured in milliseconds). Obviously this is a problem if
+you are trying to keep event service latencies down in the microsecond range.
+
+The hardware latency detector works by hogging all of the cpus for configurable
+amounts of time (by calling stop_machine()), polling the CPU Time Stamp Counter
+for some period, then looking for gaps in the TSC data. Any gap indicates a
+time when the polling was interrupted and since the machine is stopped and
+interrupts turned off the only thing that could do that would be an SMI.
+
+Note that the SMI detector should *NEVER* be used in a production environment.
+It is intended to be run manually to determine if the hardware platform has a
+problem with long system firmware service routines.
+
+Usage:
+------
+
+Loading the module hwlat_detector passing the parameter "enabled=1" (or by
+setting the "enable" entry in "hwlat_detector" debugfs toggled on) is the only
+step required to start the hwlat_detector. It is possible to redefine the
+threshold in microseconds (us) above which latency spikes will be taken
+into account (parameter "threshold=").
+
+Example:
+
+	# modprobe hwlat_detector enabled=1 threshold=100
+
+After the module is loaded, it creates a directory named "hwlat_detector" under
+the debugfs mountpoint, "/debug/hwlat_detector" for this text. It is necessary
+to have debugfs mounted, which might be on /sys/debug on your system.
+
+The /debug/hwlat_detector interface contains the following files:
+
+count			- number of latency spikes observed since last reset
+enable			- a global enable/disable toggle (0/1), resets count
+max			- maximum hardware latency actually observed (usecs)
+sample			- a pipe from which to read current raw sample data
+			  in the format <timestamp> <latency observed usecs>
+			  (can be opened O_NONBLOCK for a single sample)
+threshold		- minimum latency value to be considered (usecs)
+width			- time period to sample with CPUs held (usecs)
+			  must be less than the total window size (enforced)
+window			- total period of sampling, width being inside (usecs)
+
+By default we will set width to 500,000 and window to 1,000,000, meaning that
+we will sample every 1,000,000 usecs (1s) for 500,000 usecs (0.5s). If we
+observe any latencies that exceed the threshold (initially 100 usecs),
+then we write to a global sample ring buffer of 8K samples, which is
+consumed by reading from the "sample" (pipe) debugfs file interface.
Index: linux-3.4/MAINTAINERS
===================================================================
--- linux-3.4.orig/MAINTAINERS
+++ linux-3.4/MAINTAINERS
@@ -3082,6 +3082,15 @@ L:	linuxppc-dev@lists.ozlabs.org
 S:	Odd Fixes
 F:	drivers/tty/hvc/
 
+HARDWARE LATENCY DETECTOR
+P:	Jon Masters
+M:	jcm@jonmasters.org
+W:	http://www.kernel.org/pub/linux/kernel/people/jcm/hwlat_detector/
+S:	Supported
+L:	linux-kernel@vger.kernel.org
+F:	Documentation/hwlat_detector.txt
+F:	drivers/misc/hwlat_detector.c
+
 HARDWARE MONITORING
 M:	Jean Delvare <khali@linux-fr.org>
 M:	Guenter Roeck <guenter.roeck@ericsson.com>
Index: linux-3.4/drivers/misc/Makefile
===================================================================
--- linux-3.4.orig/drivers/misc/Makefile
+++ linux-3.4/drivers/misc/Makefile
@@ -49,3 +49,4 @@ obj-y				+= carma/
 obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o
 obj-$(CONFIG_ALTERA_STAPL)	+=altera-stapl/
 obj-$(CONFIG_MAX8997_MUIC)	+= max8997-muic.o
+obj-$(CONFIG_HWLAT_DETECTOR)	+= hwlat_detector.o
Index: linux-3.4/drivers/misc/hwlat_detector.c
===================================================================
--- /dev/null
+++ linux-3.4/drivers/misc/hwlat_detector.c
@@ -0,0 +1,1212 @@
+/*
+ * hwlat_detector.c - A simple Hardware Latency detector.
+ *
+ * Use this module to detect large system latencies induced by the behavior of
+ * certain underlying system hardware or firmware, independent of Linux itself.
+ * The code was developed originally to detect the presence of SMIs on Intel
+ * and AMD systems, although there is no dependency upon x86 herein.
+ *
+ * The classical example usage of this module is in detecting the presence of
+ * SMIs or System Management Interrupts on Intel and AMD systems. An SMI is a
+ * somewhat special form of hardware interrupt spawned from earlier CPU debug
+ * modes in which the (BIOS/EFI/etc.) firmware arranges for the South Bridge
+ * LPC (or other device) to generate a special interrupt under certain
+ * circumstances, for example, upon expiration of a special SMI timer device,
+ * due to certain external thermal readings, on certain I/O address accesses,
+ * and other situations. An SMI hits a special CPU pin, triggers a special
+ * SMI mode (complete with special memory map), and the OS is unaware.
+ *
+ * Although certain hardware-inducing latencies are necessary (for example,
+ * a modern system often requires an SMI handler for correct thermal control
+ * and remote management) they can wreak havoc upon any OS-level performance
+ * guarantees toward low-latency, especially when the OS is not even made
+ * aware of the presence of these interrupts. For this reason, we need a
+ * somewhat brute force mechanism to detect these interrupts. In this case,
+ * we do it by hogging all of the CPU(s) for configurable timer intervals,
+ * sampling the built-in CPU timer, looking for discontiguous readings.
+ *
+ * WARNING: This implementation necessarily introduces latencies. Therefore,
+ *          you should NEVER use this module in a production environment
+ *          requiring any kind of low-latency performance guarantee(s).
+ *
+ * Copyright (C) 2008-2009 Jon Masters, Red Hat, Inc. <jcm@redhat.com>
+ *
+ * Includes useful feedback from Clark Williams <clark@redhat.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/ring_buffer.h>
+#include <linux/stop_machine.h>
+#include <linux/time.h>
+#include <linux/hrtimer.h>
+#include <linux/kthread.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/version.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+#define BUF_SIZE_DEFAULT	262144UL		/* 8K*(sizeof(entry)) */
+#define BUF_FLAGS		(RB_FL_OVERWRITE)	/* no block on full */
+#define U64STR_SIZE		22			/* 20 digits max */
+
+#define VERSION			"1.0.0"
+#define BANNER			"hwlat_detector: "
+#define DRVNAME			"hwlat_detector"
+#define DEFAULT_SAMPLE_WINDOW	1000000			/* 1s */
+#define DEFAULT_SAMPLE_WIDTH	500000			/* 0.5s */
+#define DEFAULT_LAT_THRESHOLD	10			/* 10us */
+
+/* Module metadata */
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jon Masters <jcm@redhat.com>");
+MODULE_DESCRIPTION("A simple hardware latency detector");
+MODULE_VERSION(VERSION);
+
+/* Module parameters */
+
+static int debug;
+static int enabled;
+static int threshold;
+
+module_param(debug, int, 0);			/* enable debug */
+module_param(enabled, int, 0);			/* enable detector */
+module_param(threshold, int, 0);		/* latency threshold */
+
+/* Buffering and sampling */
+
+static struct ring_buffer *ring_buffer;		/* sample buffer */
+static DEFINE_MUTEX(ring_buffer_mutex);		/* lock changes */
+static unsigned long buf_size = BUF_SIZE_DEFAULT;
+static struct task_struct *kthread;		/* sampling thread */
+
+/* DebugFS filesystem entries */
+
+static struct dentry *debug_dir;		/* debugfs directory */
+static struct dentry *debug_max;		/* maximum TSC delta */
+static struct dentry *debug_count;		/* total detect count */
+static struct dentry *debug_sample_width;	/* sample width us */
+static struct dentry *debug_sample_window;	/* sample window us */
+static struct dentry *debug_sample;		/* raw samples us */
+static struct dentry *debug_threshold;		/* threshold us */
+static struct dentry *debug_enable;         	/* enable/disable */
+
+/* Individual samples and global state */
+
+struct sample;					/* latency sample */
+struct data;					/* Global state */
+
+/* Sampling functions */
+static int __buffer_add_sample(struct sample *sample);
+static struct sample *buffer_get_sample(struct sample *sample);
+static int get_sample(void *unused);
+
+/* Threading and state */
+static int kthread_fn(void *unused);
+static int start_kthread(void);
+static int stop_kthread(void);
+static void __reset_stats(void);
+static int init_stats(void);
+
+/* Debugfs interface */
+static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
+				size_t cnt, loff_t *ppos, const u64 *entry);
+static ssize_t simple_data_write(struct file *filp, const char __user *ubuf,
+				 size_t cnt, loff_t *ppos, u64 *entry);
+static int debug_sample_fopen(struct inode *inode, struct file *filp);
+static ssize_t debug_sample_fread(struct file *filp, char __user *ubuf,
+				  size_t cnt, loff_t *ppos);
+static int debug_sample_release(struct inode *inode, struct file *filp);
+static int debug_enable_fopen(struct inode *inode, struct file *filp);
+static ssize_t debug_enable_fread(struct file *filp, char __user *ubuf,
+				  size_t cnt, loff_t *ppos);
+static ssize_t debug_enable_fwrite(struct file *file,
+				   const char __user *user_buffer,
+				   size_t user_size, loff_t *offset);
+
+/* Initialization functions */
+static int init_debugfs(void);
+static void free_debugfs(void);
+static int detector_init(void);
+static void detector_exit(void);
+
+/* Individual latency samples are stored here when detected and packed into
+ * the ring_buffer circular buffer, where they are overwritten when
+ * more than buf_size/sizeof(sample) samples are received. */
+struct sample {
+	u64		seqnum;		/* unique sequence */
+	u64		duration;	/* ktime delta */
+	struct timespec	timestamp;	/* wall time */
+	unsigned long   lost;
+};
+
+/* keep the global state somewhere. Mostly used under stop_machine. */
+static struct data {
+
+	struct mutex lock;		/* protect changes */
+
+	u64	count;			/* total since reset */
+	u64	max_sample;		/* max hardware latency */
+	u64	threshold;		/* sample threshold level */
+
+	u64	sample_window;		/* total sampling window (on+off) */
+	u64	sample_width;		/* active sampling portion of window */
+
+	atomic_t sample_open;		/* whether the sample file is open */
+
+	wait_queue_head_t wq;		/* waitqeue for new sample values */
+
+} data;
+
+/**
+ * __buffer_add_sample - add a new latency sample recording to the ring buffer
+ * @sample: The new latency sample value
+ *
+ * This receives a new latency sample and records it in a global ring buffer.
+ * No additional locking is used in this case - suited for stop_machine use.
+ */
+static int __buffer_add_sample(struct sample *sample)
+{
+	return ring_buffer_write(ring_buffer,
+				 sizeof(struct sample), sample);
+}
+
+/**
+ * buffer_get_sample - remove a hardware latency sample from the ring buffer
+ * @sample: Pre-allocated storage for the sample
+ *
+ * This retrieves a hardware latency sample from the global circular buffer
+ */
+static struct sample *buffer_get_sample(struct sample *sample)
+{
+	struct ring_buffer_event *e = NULL;
+	struct sample *s = NULL;
+	unsigned int cpu = 0;
+
+	if (!sample)
+		return NULL;
+
+	mutex_lock(&ring_buffer_mutex);
+	for_each_online_cpu(cpu) {
+		e = ring_buffer_consume(ring_buffer, cpu, NULL, &sample->lost);
+		if (e)
+			break;
+	}
+
+	if (e) {
+		s = ring_buffer_event_data(e);
+		memcpy(sample, s, sizeof(struct sample));
+	} else
+		sample = NULL;
+	mutex_unlock(&ring_buffer_mutex);
+
+	return sample;
+}
+
+/**
+ * get_sample - sample the CPU TSC and look for likely hardware latencies
+ * @unused: This is not used but is a part of the stop_machine API
+ *
+ * Used to repeatedly capture the CPU TSC (or similar), looking for potential
+ * hardware-induced latency. Called under stop_machine, with data.lock held.
+ */
+static int get_sample(void *unused)
+{
+	ktime_t start, t1, t2;
+	s64 diff, total = 0;
+	u64 sample = 0;
+	int ret = 1;
+
+	start = ktime_get(); /* start timestamp */
+
+	do {
+
+		t1 = ktime_get();	/* we'll look for a discontinuity */
+		t2 = ktime_get();
+
+		total = ktime_to_us(ktime_sub(t2, start)); /* sample width */
+		diff = ktime_to_us(ktime_sub(t2, t1));     /* current diff */
+
+		/* This shouldn't happen */
+		if (diff < 0) {
+			printk(KERN_ERR BANNER "time running backwards\n");
+			goto out;
+		}
+
+		if (diff > sample)
+			sample = diff; /* only want highest value */
+
+	} while (total <= data.sample_width);
+
+	/* If we exceed the threshold value, we have found a hardware latency */
+	if (sample > data.threshold) {
+		struct sample s;
+
+		data.count++;
+		s.seqnum = data.count;
+		s.duration = sample;
+		s.timestamp = CURRENT_TIME;
+		__buffer_add_sample(&s);
+
+		/* Keep a running maximum ever recorded hardware latency */
+		if (sample > data.max_sample)
+			data.max_sample = sample;
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+/*
+ * kthread_fn - The CPU time sampling/hardware latency detection kernel thread
+ * @unused: A required part of the kthread API.
+ *
+ * Used to periodically sample the CPU TSC via a call to get_sample. We
+ * use stop_machine, whith does (intentionally) introduce latency since we
+ * need to ensure nothing else might be running (and thus pre-empting).
+ * Obviously this should never be used in production environments.
+ *
+ * stop_machine will schedule us typically only on CPU0 which is fine for
+ * almost every real-world hardware latency situation - but we might later
+ * generalize this if we find there are any actualy systems with alternate
+ * SMI delivery or other non CPU0 hardware latencies.
+ */
+static int kthread_fn(void *unused)
+{
+	int err = 0;
+	u64 interval = 0;
+
+	while (!kthread_should_stop()) {
+
+		mutex_lock(&data.lock);
+
+		err = stop_machine(get_sample, unused, 0);
+		if (err) {
+			/* Houston, we have a problem */
+			mutex_unlock(&data.lock);
+			goto err_out;
+		}
+
+		wake_up(&data.wq); /* wake up reader(s) */
+
+		interval = data.sample_window - data.sample_width;
+		do_div(interval, USEC_PER_MSEC); /* modifies interval value */
+
+		mutex_unlock(&data.lock);
+
+		if (msleep_interruptible(interval))
+			goto out;
+	}
+		goto out;
+err_out:
+	printk(KERN_ERR BANNER "could not call stop_machine, disabling\n");
+	enabled = 0;
+out:
+	return err;
+
+}
+
+/**
+ * start_kthread - Kick off the hardware latency sampling/detector kthread
+ *
+ * This starts a kernel thread that will sit and sample the CPU timestamp
+ * counter (TSC or similar) and look for potential hardware latencies.
+ */
+static int start_kthread(void)
+{
+	kthread = kthread_run(kthread_fn, NULL,
+					DRVNAME);
+	if (IS_ERR(kthread)) {
+		printk(KERN_ERR BANNER "could not start sampling thread\n");
+		enabled = 0;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * stop_kthread - Inform the hardware latency samping/detector kthread to stop
+ *
+ * This kicks the running hardware latency sampling/detector kernel thread and
+ * tells it to stop sampling now. Use this on unload and at system shutdown.
+ */
+static int stop_kthread(void)
+{
+	int ret;
+
+	ret = kthread_stop(kthread);
+
+	return ret;
+}
+
+/**
+ * __reset_stats - Reset statistics for the hardware latency detector
+ *
+ * We use data to store various statistics and global state. We call this
+ * function in order to reset those when "enable" is toggled on or off, and
+ * also at initialization. Should be called with data.lock held.
+ */
+static void __reset_stats(void)
+{
+	data.count = 0;
+	data.max_sample = 0;
+	ring_buffer_reset(ring_buffer); /* flush out old sample entries */
+}
+
+/**
+ * init_stats - Setup global state statistics for the hardware latency detector
+ *
+ * We use data to store various statistics and global state. We also use
+ * a global ring buffer (ring_buffer) to keep raw samples of detected hardware
+ * induced system latencies. This function initializes these structures and
+ * allocates the global ring buffer also.
+ */
+static int init_stats(void)
+{
+	int ret = -ENOMEM;
+
+	mutex_init(&data.lock);
+	init_waitqueue_head(&data.wq);
+	atomic_set(&data.sample_open, 0);
+
+	ring_buffer = ring_buffer_alloc(buf_size, BUF_FLAGS);
+
+	if (WARN(!ring_buffer, KERN_ERR BANNER
+			       "failed to allocate ring buffer!\n"))
+		goto out;
+
+	__reset_stats();
+	data.threshold = DEFAULT_LAT_THRESHOLD;	    /* threshold us */
+	data.sample_window = DEFAULT_SAMPLE_WINDOW; /* window us */
+	data.sample_width = DEFAULT_SAMPLE_WIDTH;   /* width us */
+
+	ret = 0;
+
+out:
+	return ret;
+
+}
+
+/*
+ * simple_data_read - Wrapper read function for global state debugfs entries
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ * @entry: The entry to read from
+ *
+ * This function provides a generic read implementation for the global state
+ * "data" structure debugfs filesystem entries. It would be nice to use
+ * simple_attr_read directly, but we need to make sure that the data.lock
+ * spinlock is held during the actual read (even though we likely won't ever
+ * actually race here as the updater runs under a stop_machine context).
+ */
+static ssize_t simple_data_read(struct file *filp, char __user *ubuf,
+				size_t cnt, loff_t *ppos, const u64 *entry)
+{
+	char buf[U64STR_SIZE];
+	u64 val = 0;
+	int len = 0;
+
+	memset(buf, 0, sizeof(buf));
+
+	if (!entry)
+		return -EFAULT;
+
+	mutex_lock(&data.lock);
+	val = *entry;
+	mutex_unlock(&data.lock);
+
+	len = snprintf(buf, sizeof(buf), "%llu\n", (unsigned long long)val);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
+
+}
+
+/*
+ * simple_data_write - Wrapper write function for global state debugfs entries
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to write value from
+ * @cnt: The maximum number of bytes to write
+ * @ppos: The current "file" position
+ * @entry: The entry to write to
+ *
+ * This function provides a generic write implementation for the global state
+ * "data" structure debugfs filesystem entries. It would be nice to use
+ * simple_attr_write directly, but we need to make sure that the data.lock
+ * spinlock is held during the actual write (even though we likely won't ever
+ * actually race here as the updater runs under a stop_machine context).
+ */
+static ssize_t simple_data_write(struct file *filp, const char __user *ubuf,
+				 size_t cnt, loff_t *ppos, u64 *entry)
+{
+	char buf[U64STR_SIZE];
+	int csize = min(cnt, sizeof(buf));
+	u64 val = 0;
+	int err = 0;
+
+	memset(buf, '\0', sizeof(buf));
+	if (copy_from_user(buf, ubuf, csize))
+		return -EFAULT;
+
+	buf[U64STR_SIZE-1] = '\0';			/* just in case */
+	err = strict_strtoull(buf, 10, &val);
+	if (err)
+		return -EINVAL;
+
+	mutex_lock(&data.lock);
+	*entry = val;
+	mutex_unlock(&data.lock);
+
+	return csize;
+}
+
+/**
+ * debug_count_fopen - Open function for "count" debugfs entry
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "count" debugfs
+ * interface to the hardware latency detector.
+ */
+static int debug_count_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_count_fread - Read function for "count" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "count" debugfs
+ * interface to the hardware latency detector. Can be used to read the
+ * number of latency readings exceeding the configured threshold since
+ * the detector was last reset (e.g. by writing a zero into "count").
+ */
+static ssize_t debug_count_fread(struct file *filp, char __user *ubuf,
+				     size_t cnt, loff_t *ppos)
+{
+	return simple_data_read(filp, ubuf, cnt, ppos, &data.count);
+}
+
+/**
+ * debug_count_fwrite - Write function for "count" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "count" debugfs
+ * interface to the hardware latency detector. Can be used to write a
+ * desired value, especially to zero the total count.
+ */
+static ssize_t  debug_count_fwrite(struct file *filp,
+				       const char __user *ubuf,
+				       size_t cnt,
+				       loff_t *ppos)
+{
+	return simple_data_write(filp, ubuf, cnt, ppos, &data.count);
+}
+
+/**
+ * debug_enable_fopen - Dummy open function for "enable" debugfs interface
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "enable" debugfs
+ * interface to the hardware latency detector.
+ */
+static int debug_enable_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_enable_fread - Read function for "enable" debugfs interface
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "enable" debugfs
+ * interface to the hardware latency detector. Can be used to determine
+ * whether the detector is currently enabled ("0\n" or "1\n" returned).
+ */
+static ssize_t debug_enable_fread(struct file *filp, char __user *ubuf,
+				      size_t cnt, loff_t *ppos)
+{
+	char buf[4];
+
+	if ((cnt < sizeof(buf)) || (*ppos))
+		return 0;
+
+	buf[0] = enabled ? '1' : '0';
+	buf[1] = '\n';
+	buf[2] = '\0';
+	if (copy_to_user(ubuf, buf, strlen(buf)))
+		return -EFAULT;
+	return *ppos = strlen(buf);
+}
+
+/**
+ * debug_enable_fwrite - Write function for "enable" debugfs interface
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "enable" debugfs
+ * interface to the hardware latency detector. Can be used to enable or
+ * disable the detector, which will have the side-effect of possibly
+ * also resetting the global stats and kicking off the measuring
+ * kthread (on an enable) or the converse (upon a disable).
+ */
+static ssize_t  debug_enable_fwrite(struct file *filp,
+					const char __user *ubuf,
+					size_t cnt,
+					loff_t *ppos)
+{
+	char buf[4];
+	int csize = min(cnt, sizeof(buf));
+	long val = 0;
+	int err = 0;
+
+	memset(buf, '\0', sizeof(buf));
+	if (copy_from_user(buf, ubuf, csize))
+		return -EFAULT;
+
+	buf[sizeof(buf)-1] = '\0';			/* just in case */
+	err = strict_strtoul(buf, 10, &val);
+	if (0 != err)
+		return -EINVAL;
+
+	if (val) {
+		if (enabled)
+			goto unlock;
+		enabled = 1;
+		__reset_stats();
+		if (start_kthread())
+			return -EFAULT;
+	} else {
+		if (!enabled)
+			goto unlock;
+		enabled = 0;
+		err = stop_kthread();
+		if (err) {
+			printk(KERN_ERR BANNER "cannot stop kthread\n");
+			return -EFAULT;
+		}
+		wake_up(&data.wq);		/* reader(s) should return */
+	}
+unlock:
+	return csize;
+}
+
+/**
+ * debug_max_fopen - Open function for "max" debugfs entry
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "max" debugfs
+ * interface to the hardware latency detector.
+ */
+static int debug_max_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_max_fread - Read function for "max" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "max" debugfs
+ * interface to the hardware latency detector. Can be used to determine
+ * the maximum latency value observed since it was last reset.
+ */
+static ssize_t debug_max_fread(struct file *filp, char __user *ubuf,
+				   size_t cnt, loff_t *ppos)
+{
+	return simple_data_read(filp, ubuf, cnt, ppos, &data.max_sample);
+}
+
+/**
+ * debug_max_fwrite - Write function for "max" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "max" debugfs
+ * interface to the hardware latency detector. Can be used to reset the
+ * maximum or set it to some other desired value - if, then, subsequent
+ * measurements exceed this value, the maximum will be updated.
+ */
+static ssize_t  debug_max_fwrite(struct file *filp,
+				     const char __user *ubuf,
+				     size_t cnt,
+				     loff_t *ppos)
+{
+	return simple_data_write(filp, ubuf, cnt, ppos, &data.max_sample);
+}
+
+
+/**
+ * debug_sample_fopen - An open function for "sample" debugfs interface
+ * @inode: The in-kernel inode representation of this debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function handles opening the "sample" file within the hardware
+ * latency detector debugfs directory interface. This file is used to read
+ * raw samples from the global ring_buffer and allows the user to see a
+ * running latency history. Can be opened blocking or non-blocking,
+ * affecting whether it behaves as a buffer read pipe, or does not.
+ * Implements simple locking to prevent multiple simultaneous use.
+ */
+static int debug_sample_fopen(struct inode *inode, struct file *filp)
+{
+	if (!atomic_add_unless(&data.sample_open, 1, 1))
+		return -EBUSY;
+	else
+		return 0;
+}
+
+/**
+ * debug_sample_fread - A read function for "sample" debugfs interface
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that will contain the samples read
+ * @cnt: The maximum bytes to read from the debugfs "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function handles reading from the "sample" file within the hardware
+ * latency detector debugfs directory interface. This file is used to read
+ * raw samples from the global ring_buffer and allows the user to see a
+ * running latency history. By default this will block pending a new
+ * value written into the sample buffer, unless there are already a
+ * number of value(s) waiting in the buffer, or the sample file was
+ * previously opened in a non-blocking mode of operation.
+ */
+static ssize_t debug_sample_fread(struct file *filp, char __user *ubuf,
+					size_t cnt, loff_t *ppos)
+{
+	int len = 0;
+	char buf[64];
+	struct sample *sample = NULL;
+
+	if (!enabled)
+		return 0;
+
+	sample = kzalloc(sizeof(struct sample), GFP_KERNEL);
+	if (!sample)
+		return -ENOMEM;
+
+	while (!buffer_get_sample(sample)) {
+
+		DEFINE_WAIT(wait);
+
+		if (filp->f_flags & O_NONBLOCK) {
+			len = -EAGAIN;
+			goto out;
+		}
+
+		prepare_to_wait(&data.wq, &wait, TASK_INTERRUPTIBLE);
+		schedule();
+		finish_wait(&data.wq, &wait);
+
+		if (signal_pending(current)) {
+			len = -EINTR;
+			goto out;
+		}
+
+		if (!enabled) {			/* enable was toggled */
+			len = 0;
+			goto out;
+		}
+	}
+
+	len = snprintf(buf, sizeof(buf), "%010lu.%010lu\t%llu\n",
+		      sample->timestamp.tv_sec,
+		      sample->timestamp.tv_nsec,
+		      sample->duration);
+
+
+	/* handling partial reads is more trouble than it's worth */
+	if (len > cnt)
+		goto out;
+
+	if (copy_to_user(ubuf, buf, len))
+		len = -EFAULT;
+
+out:
+	kfree(sample);
+	return len;
+}
+
+/**
+ * debug_sample_release - Release function for "sample" debugfs interface
+ * @inode: The in-kernel inode represenation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function completes the close of the debugfs interface "sample" file.
+ * Frees the sample_open "lock" so that other users may open the interface.
+ */
+static int debug_sample_release(struct inode *inode, struct file *filp)
+{
+	atomic_dec(&data.sample_open);
+
+	return 0;
+}
+
+/**
+ * debug_threshold_fopen - Open function for "threshold" debugfs entry
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "threshold" debugfs
+ * interface to the hardware latency detector.
+ */
+static int debug_threshold_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_threshold_fread - Read function for "threshold" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "threshold" debugfs
+ * interface to the hardware latency detector. It can be used to determine
+ * the current threshold level at which a latency will be recorded in the
+ * global ring buffer, typically on the order of 10us.
+ */
+static ssize_t debug_threshold_fread(struct file *filp, char __user *ubuf,
+					 size_t cnt, loff_t *ppos)
+{
+	return simple_data_read(filp, ubuf, cnt, ppos, &data.threshold);
+}
+
+/**
+ * debug_threshold_fwrite - Write function for "threshold" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "threshold" debugfs
+ * interface to the hardware latency detector. It can be used to configure
+ * the threshold level at which any subsequently detected latencies will
+ * be recorded into the global ring buffer.
+ */
+static ssize_t  debug_threshold_fwrite(struct file *filp,
+					const char __user *ubuf,
+					size_t cnt,
+					loff_t *ppos)
+{
+	int ret;
+
+	ret = simple_data_write(filp, ubuf, cnt, ppos, &data.threshold);
+
+	if (enabled)
+		wake_up_process(kthread);
+
+	return ret;
+}
+
+/**
+ * debug_width_fopen - Open function for "width" debugfs entry
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "width" debugfs
+ * interface to the hardware latency detector.
+ */
+static int debug_width_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_width_fread - Read function for "width" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "width" debugfs
+ * interface to the hardware latency detector. It can be used to determine
+ * for how many us of the total window us we will actively sample for any
+ * hardware-induced latecy periods. Obviously, it is not possible to
+ * sample constantly and have the system respond to a sample reader, or,
+ * worse, without having the system appear to have gone out to lunch.
+ */
+static ssize_t debug_width_fread(struct file *filp, char __user *ubuf,
+				     size_t cnt, loff_t *ppos)
+{
+	return simple_data_read(filp, ubuf, cnt, ppos, &data.sample_width);
+}
+
+/**
+ * debug_width_fwrite - Write function for "width" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "width" debugfs
+ * interface to the hardware latency detector. It can be used to configure
+ * for how many us of the total window us we will actively sample for any
+ * hardware-induced latency periods. Obviously, it is not possible to
+ * sample constantly and have the system respond to a sample reader, or,
+ * worse, without having the system appear to have gone out to lunch. It
+ * is enforced that width is less that the total window size.
+ */
+static ssize_t  debug_width_fwrite(struct file *filp,
+				       const char __user *ubuf,
+				       size_t cnt,
+				       loff_t *ppos)
+{
+	char buf[U64STR_SIZE];
+	int csize = min(cnt, sizeof(buf));
+	u64 val = 0;
+	int err = 0;
+
+	memset(buf, '\0', sizeof(buf));
+	if (copy_from_user(buf, ubuf, csize))
+		return -EFAULT;
+
+	buf[U64STR_SIZE-1] = '\0';			/* just in case */
+	err = strict_strtoull(buf, 10, &val);
+	if (0 != err)
+		return -EINVAL;
+
+	mutex_lock(&data.lock);
+	if (val < data.sample_window)
+		data.sample_width = val;
+	else {
+		mutex_unlock(&data.lock);
+		return -EINVAL;
+	}
+	mutex_unlock(&data.lock);
+
+	if (enabled)
+		wake_up_process(kthread);
+
+	return csize;
+}
+
+/**
+ * debug_window_fopen - Open function for "window" debugfs entry
+ * @inode: The in-kernel inode representation of the debugfs "file"
+ * @filp: The active open file structure for the debugfs "file"
+ *
+ * This function provides an open implementation for the "window" debugfs
+ * interface to the hardware latency detector. The window is the total time
+ * in us that will be considered one sample period. Conceptually, windows
+ * occur back-to-back and contain a sample width period during which
+ * actual sampling occurs.
+ */
+static int debug_window_fopen(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/**
+ * debug_window_fread - Read function for "window" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The userspace provided buffer to read value into
+ * @cnt: The maximum number of bytes to read
+ * @ppos: The current "file" position
+ *
+ * This function provides a read implementation for the "window" debugfs
+ * interface to the hardware latency detector. The window is the total time
+ * in us that will be considered one sample period. Conceptually, windows
+ * occur back-to-back and contain a sample width period during which
+ * actual sampling occurs. Can be used to read the total window size.
+ */
+static ssize_t debug_window_fread(struct file *filp, char __user *ubuf,
+				      size_t cnt, loff_t *ppos)
+{
+	return simple_data_read(filp, ubuf, cnt, ppos, &data.sample_window);
+}
+
+/**
+ * debug_window_fwrite - Write function for "window" debugfs entry
+ * @filp: The active open file structure for the debugfs "file"
+ * @ubuf: The user buffer that contains the value to write
+ * @cnt: The maximum number of bytes to write to "file"
+ * @ppos: The current position in the debugfs "file"
+ *
+ * This function provides a write implementation for the "window" debufds
+ * interface to the hardware latency detetector. The window is the total time
+ * in us that will be considered one sample period. Conceptually, windows
+ * occur back-to-back and contain a sample width period during which
+ * actual sampling occurs. Can be used to write a new total window size. It
+ * is enfoced that any value written must be greater than the sample width
+ * size, or an error results.
+ */
+static ssize_t  debug_window_fwrite(struct file *filp,
+					const char __user *ubuf,
+					size_t cnt,
+					loff_t *ppos)
+{
+	char buf[U64STR_SIZE];
+	int csize = min(cnt, sizeof(buf));
+	u64 val = 0;
+	int err = 0;
+
+	memset(buf, '\0', sizeof(buf));
+	if (copy_from_user(buf, ubuf, csize))
+		return -EFAULT;
+
+	buf[U64STR_SIZE-1] = '\0';			/* just in case */
+	err = strict_strtoull(buf, 10, &val);
+	if (0 != err)
+		return -EINVAL;
+
+	mutex_lock(&data.lock);
+	if (data.sample_width < val)
+		data.sample_window = val;
+	else {
+		mutex_unlock(&data.lock);
+		return -EINVAL;
+	}
+	mutex_unlock(&data.lock);
+
+	return csize;
+}
+
+/*
+ * Function pointers for the "count" debugfs file operations
+ */
+static const struct file_operations count_fops = {
+	.open		= debug_count_fopen,
+	.read		= debug_count_fread,
+	.write		= debug_count_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "enable" debugfs file operations
+ */
+static const struct file_operations enable_fops = {
+	.open		= debug_enable_fopen,
+	.read		= debug_enable_fread,
+	.write		= debug_enable_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "max" debugfs file operations
+ */
+static const struct file_operations max_fops = {
+	.open		= debug_max_fopen,
+	.read		= debug_max_fread,
+	.write		= debug_max_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "sample" debugfs file operations
+ */
+static const struct file_operations sample_fops = {
+	.open 		= debug_sample_fopen,
+	.read		= debug_sample_fread,
+	.release	= debug_sample_release,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "threshold" debugfs file operations
+ */
+static const struct file_operations threshold_fops = {
+	.open		= debug_threshold_fopen,
+	.read		= debug_threshold_fread,
+	.write		= debug_threshold_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "width" debugfs file operations
+ */
+static const struct file_operations width_fops = {
+	.open		= debug_width_fopen,
+	.read		= debug_width_fread,
+	.write		= debug_width_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/*
+ * Function pointers for the "window" debugfs file operations
+ */
+static const struct file_operations window_fops = {
+	.open		= debug_window_fopen,
+	.read		= debug_window_fread,
+	.write		= debug_window_fwrite,
+	.owner		= THIS_MODULE,
+};
+
+/**
+ * init_debugfs - A function to initialize the debugfs interface files
+ *
+ * This function creates entries in debugfs for "hwlat_detector", including
+ * files to read values from the detector, current samples, and the
+ * maximum sample that has been captured since the hardware latency
+ * dectector was started.
+ */
+static int init_debugfs(void)
+{
+	int ret = -ENOMEM;
+
+	debug_dir = debugfs_create_dir(DRVNAME, NULL);
+	if (!debug_dir)
+		goto err_debug_dir;
+
+	debug_sample = debugfs_create_file("sample", 0444,
+					       debug_dir, NULL,
+					       &sample_fops);
+	if (!debug_sample)
+		goto err_sample;
+
+	debug_count = debugfs_create_file("count", 0444,
+					      debug_dir, NULL,
+					      &count_fops);
+	if (!debug_count)
+		goto err_count;
+
+	debug_max = debugfs_create_file("max", 0444,
+					    debug_dir, NULL,
+					    &max_fops);
+	if (!debug_max)
+		goto err_max;
+
+	debug_sample_window = debugfs_create_file("window", 0644,
+						      debug_dir, NULL,
+						      &window_fops);
+	if (!debug_sample_window)
+		goto err_window;
+
+	debug_sample_width = debugfs_create_file("width", 0644,
+						     debug_dir, NULL,
+						     &width_fops);
+	if (!debug_sample_width)
+		goto err_width;
+
+	debug_threshold = debugfs_create_file("threshold", 0644,
+						  debug_dir, NULL,
+						  &threshold_fops);
+	if (!debug_threshold)
+		goto err_threshold;
+
+	debug_enable = debugfs_create_file("enable", 0644,
+					       debug_dir, &enabled,
+					       &enable_fops);
+	if (!debug_enable)
+		goto err_enable;
+
+	else {
+		ret = 0;
+		goto out;
+	}
+
+err_enable:
+	debugfs_remove(debug_threshold);
+err_threshold:
+	debugfs_remove(debug_sample_width);
+err_width:
+	debugfs_remove(debug_sample_window);
+err_window:
+	debugfs_remove(debug_max);
+err_max:
+	debugfs_remove(debug_count);
+err_count:
+	debugfs_remove(debug_sample);
+err_sample:
+	debugfs_remove(debug_dir);
+err_debug_dir:
+out:
+	return ret;
+}
+
+/**
+ * free_debugfs - A function to cleanup the debugfs file interface
+ */
+static void free_debugfs(void)
+{
+	/* could also use a debugfs_remove_recursive */
+	debugfs_remove(debug_enable);
+	debugfs_remove(debug_threshold);
+	debugfs_remove(debug_sample_width);
+	debugfs_remove(debug_sample_window);
+	debugfs_remove(debug_max);
+	debugfs_remove(debug_count);
+	debugfs_remove(debug_sample);
+	debugfs_remove(debug_dir);
+}
+
+/**
+ * detector_init - Standard module initialization code
+ */
+static int detector_init(void)
+{
+	int ret = -ENOMEM;
+
+	printk(KERN_INFO BANNER "version %s\n", VERSION);
+
+	ret = init_stats();
+	if (0 != ret)
+		goto out;
+
+	ret = init_debugfs();
+	if (0 != ret)
+		goto err_stats;
+
+	if (enabled)
+		ret = start_kthread();
+
+	goto out;
+
+err_stats:
+	ring_buffer_free(ring_buffer);
+out:
+	return ret;
+
+}
+
+/**
+ * detector_exit - Standard module cleanup code
+ */
+static void detector_exit(void)
+{
+	int err;
+
+	if (enabled) {
+		enabled = 0;
+		err = stop_kthread();
+		if (err)
+			printk(KERN_ERR BANNER "cannot stop kthread\n");
+	}
+
+	free_debugfs();
+	ring_buffer_free(ring_buffer);	/* free up the ring buffer */
+
+}
+
+module_init(detector_init);
+module_exit(detector_exit);
Index: linux-3.4/localversion-rt
===================================================================
--- /dev/null
+++ linux-3.4/localversion-rt
@@ -0,0 +1 @@
+-rt6
Index: linux-3.4/arch/arm/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/arm/kernel/early_printk.c
+++ linux-3.4/arch/arm/kernel/early_printk.c
@@ -29,28 +29,17 @@ static void early_console_write(struct c
 	early_write(s, n);
 }
 
-static struct console early_console = {
+static struct console early_console_dev = {
 	.name =		"earlycon",
 	.write =	early_console_write,
 	.flags =	CON_PRINTBUFFER | CON_BOOT,
 	.index =	-1,
 };
 
-asmlinkage void early_printk(const char *fmt, ...)
-{
-	char buf[512];
-	int n;
-	va_list ap;
-
-	va_start(ap, fmt);
-	n = vscnprintf(buf, sizeof(buf), fmt, ap);
-	early_write(buf, n);
-	va_end(ap);
-}
-
 static int __init setup_early_printk(char *buf)
 {
-	register_console(&early_console);
+	early_console = &early_console_dev;
+	register_console(&early_console_dev);
 	return 0;
 }
 
Index: linux-3.4/arch/blackfin/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/blackfin/kernel/early_printk.c
+++ linux-3.4/arch/blackfin/kernel/early_printk.c
@@ -25,8 +25,6 @@ extern struct console *bfin_earlyserial_
 extern struct console *bfin_jc_early_init(void);
 #endif
 
-static struct console *early_console;
-
 /* Default console */
 #define DEFAULT_PORT 0
 #define DEFAULT_CFLAG CS8|B57600
Index: linux-3.4/arch/microblaze/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/microblaze/kernel/early_printk.c
+++ linux-3.4/arch/microblaze/kernel/early_printk.c
@@ -21,7 +21,6 @@
 #include <asm/setup.h>
 #include <asm/prom.h>
 
-static u32 early_console_initialized;
 static u32 base_addr;
 
 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
@@ -109,27 +108,11 @@ static struct console early_serial_uart1
 };
 #endif /* CONFIG_SERIAL_8250_CONSOLE */
 
-static struct console *early_console;
-
-void early_printk(const char *fmt, ...)
-{
-	char buf[512];
-	int n;
-	va_list ap;
-
-	if (early_console_initialized) {
-		va_start(ap, fmt);
-		n = vscnprintf(buf, 512, fmt, ap);
-		early_console->write(early_console, buf, n);
-		va_end(ap);
-	}
-}
-
 int __init setup_early_printk(char *opt)
 {
 	int version = 0;
 
-	if (early_console_initialized)
+	if (early_console)
 		return 1;
 
 	base_addr = of_early_console(&version);
@@ -159,7 +142,6 @@ int __init setup_early_printk(char *opt)
 		}
 
 		register_console(early_console);
-		early_console_initialized = 1;
 		return 0;
 	}
 	return 1;
@@ -169,7 +151,7 @@ int __init setup_early_printk(char *opt)
  * only for early console because of performance degression */
 void __init remap_early_printk(void)
 {
-	if (!early_console_initialized || !early_console)
+	if (!early_console)
 		return;
 	printk(KERN_INFO "early_printk_console remapping from 0x%x to ",
 								base_addr);
@@ -195,9 +177,9 @@ void __init remap_early_printk(void)
 
 void __init disable_early_printk(void)
 {
-	if (!early_console_initialized || !early_console)
+	if (!early_console)
 		return;
 	printk(KERN_WARNING "disabling early console\n");
 	unregister_console(early_console);
-	early_console_initialized = 0;
+	early_console = NULL;
 }
Index: linux-3.4/arch/mips/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/mips/kernel/early_printk.c
+++ linux-3.4/arch/mips/kernel/early_printk.c
@@ -25,20 +25,18 @@ early_console_write(struct console *con,
 	}
 }
 
-static struct console early_console __initdata = {
+static struct console early_console_prom = {
 	.name	= "early",
 	.write	= early_console_write,
 	.flags	= CON_PRINTBUFFER | CON_BOOT,
 	.index	= -1
 };
 
-static int early_console_initialized __initdata;
-
 void __init setup_early_printk(void)
 {
-	if (early_console_initialized)
+	if (early_console)
 		return;
-	early_console_initialized = 1;
+	early_console = &early_console_prom;
 
-	register_console(&early_console);
+	register_console(&early_console_prom);
 }
Index: linux-3.4/arch/powerpc/kernel/udbg.c
===================================================================
--- linux-3.4.orig/arch/powerpc/kernel/udbg.c
+++ linux-3.4/arch/powerpc/kernel/udbg.c
@@ -179,15 +179,13 @@ static struct console udbg_console = {
 	.index	= 0,
 };
 
-static int early_console_initialized;
-
 /*
  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
  * Call it again after setting udbg_putc in ppc_md->setup_arch.
  */
 void __init register_early_udbg_console(void)
 {
-	if (early_console_initialized)
+	if (early_console)
 		return;
 
 	if (!udbg_putc)
@@ -197,7 +195,7 @@ void __init register_early_udbg_console(
 		printk(KERN_INFO "early console immortal !\n");
 		udbg_console.flags &= ~CON_BOOT;
 	}
-	early_console_initialized = 1;
+	early_console = &udbg_console;
 	register_console(&udbg_console);
 }
 
Index: linux-3.4/arch/sh/kernel/sh_bios.c
===================================================================
--- linux-3.4.orig/arch/sh/kernel/sh_bios.c
+++ linux-3.4/arch/sh/kernel/sh_bios.c
@@ -144,8 +144,6 @@ static struct console bios_console = {
 	.index		= -1,
 };
 
-static struct console *early_console;
-
 static int __init setup_early_printk(char *buf)
 {
 	int keep_early = 0;
Index: linux-3.4/arch/sparc/kernel/setup_32.c
===================================================================
--- linux-3.4.orig/arch/sparc/kernel/setup_32.c
+++ linux-3.4/arch/sparc/kernel/setup_32.c
@@ -221,6 +221,7 @@ void __init setup_arch(char **cmdline_p)
 
 	boot_flags_init(*cmdline_p);
 
+	early_console = &prom_early_console;
 	register_console(&prom_early_console);
 
 	/* Set sparc_cpu_model */
Index: linux-3.4/arch/sparc/kernel/setup_64.c
===================================================================
--- linux-3.4.orig/arch/sparc/kernel/setup_64.c
+++ linux-3.4/arch/sparc/kernel/setup_64.c
@@ -487,6 +487,12 @@ static void __init init_sparc64_elf_hwca
 		popc_patch();
 }
 
+static inline void register_prom_console(void)
+{
+	early_console = &prom_early_console;
+	register_console(&prom_early_console);
+}
+
 void __init setup_arch(char **cmdline_p)
 {
 	/* Initialize PROM console and command line. */
@@ -498,7 +504,7 @@ void __init setup_arch(char **cmdline_p)
 #ifdef CONFIG_EARLYFB
 	if (btext_find_display())
 #endif
-		register_console(&prom_early_console);
+		register_prom_console();
 
 	if (tlb_type == hypervisor)
 		printk("ARCH: SUN4V\n");
Index: linux-3.4/arch/tile/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/tile/kernel/early_printk.c
+++ linux-3.4/arch/tile/kernel/early_printk.c
@@ -33,25 +33,8 @@ static struct console early_hv_console =
 };
 
 /* Direct interface for emergencies */
-static struct console *early_console = &early_hv_console;
-static int early_console_initialized;
 static int early_console_complete;
 
-static void early_vprintk(const char *fmt, va_list ap)
-{
-	char buf[512];
-	int n = vscnprintf(buf, sizeof(buf), fmt, ap);
-	early_console->write(early_console, buf, n);
-}
-
-void early_printk(const char *fmt, ...)
-{
-	va_list ap;
-	va_start(ap, fmt);
-	early_vprintk(fmt, ap);
-	va_end(ap);
-}
-
 void early_panic(const char *fmt, ...)
 {
 	va_list ap;
@@ -69,14 +52,13 @@ static int __initdata keep_early;
 
 static int __init setup_early_printk(char *str)
 {
-	if (early_console_initialized)
+	if (early_console)
 		return 1;
 
 	if (str != NULL && strncmp(str, "keep", 4) == 0)
 		keep_early = 1;
 
 	early_console = &early_hv_console;
-	early_console_initialized = 1;
 	register_console(early_console);
 
 	return 0;
@@ -85,12 +67,12 @@ static int __init setup_early_printk(cha
 void __init disable_early_printk(void)
 {
 	early_console_complete = 1;
-	if (!early_console_initialized || !early_console)
+	if (!early_console)
 		return;
 	if (!keep_early) {
 		early_printk("disabling early console\n");
 		unregister_console(early_console);
-		early_console_initialized = 0;
+		early_console = NULL;
 	} else {
 		early_printk("keeping early console\n");
 	}
@@ -98,7 +80,7 @@ void __init disable_early_printk(void)
 
 void warn_early_printk(void)
 {
-	if (early_console_complete || early_console_initialized)
+	if (early_console_complete || early_console)
 		return;
 	early_printk("\
 Machine shutting down before console output is fully initialized.\n\
Index: linux-3.4/arch/um/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/um/kernel/early_printk.c
+++ linux-3.4/arch/um/kernel/early_printk.c
@@ -16,7 +16,7 @@ static void early_console_write(struct c
 	um_early_printk(s, n);
 }
 
-static struct console early_console = {
+static struct console early_console_dev = {
 	.name = "earlycon",
 	.write = early_console_write,
 	.flags = CON_BOOT,
@@ -25,8 +25,10 @@ static struct console early_console = {
 
 static int __init setup_early_printk(char *buf)
 {
-	register_console(&early_console);
-
+	if (!early_console) {
+		early_console = &early_console_dev;
+		register_console(&early_console_dev);
+	}
 	return 0;
 }
 
Index: linux-3.4/arch/unicore32/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/unicore32/kernel/early_printk.c
+++ linux-3.4/arch/unicore32/kernel/early_printk.c
@@ -33,21 +33,17 @@ static struct console early_ocd_console 
 	.index =	-1,
 };
 
-/* Direct interface for emergencies */
-static struct console *early_console = &early_ocd_console;
-
-static int __initdata keep_early;
-
 static int __init setup_early_printk(char *buf)
 {
-	if (!buf)
+	int keep_early;
+
+	if (!buf || early_console)
 		return 0;
 
 	if (strstr(buf, "keep"))
 		keep_early = 1;
 
-	if (!strncmp(buf, "ocd", 3))
-		early_console = &early_ocd_console;
+	early_console = &early_ocd_console;
 
 	if (keep_early)
 		early_console->flags &= ~CON_BOOT;
Index: linux-3.4/arch/x86/kernel/early_printk.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/early_printk.c
+++ linux-3.4/arch/x86/kernel/early_printk.c
@@ -169,25 +169,9 @@ static struct console early_serial_conso
 	.index =	-1,
 };
 
-/* Direct interface for emergencies */
-static struct console *early_console = &early_vga_console;
-static int __initdata early_console_initialized;
-
-asmlinkage void early_printk(const char *fmt, ...)
-{
-	char buf[512];
-	int n;
-	va_list ap;
-
-	va_start(ap, fmt);
-	n = vscnprintf(buf, sizeof(buf), fmt, ap);
-	early_console->write(early_console, buf, n);
-	va_end(ap);
-}
-
 static inline void early_console_register(struct console *con, int keep_early)
 {
-	if (early_console->index != -1) {
+	if (con->index != -1) {
 		printk(KERN_CRIT "ERROR: earlyprintk= %s already used\n",
 		       con->name);
 		return;
@@ -207,9 +191,8 @@ static int __init setup_early_printk(cha
 	if (!buf)
 		return 0;
 
-	if (early_console_initialized)
+	if (early_console)
 		return 0;
-	early_console_initialized = 1;
 
 	keep = (strstr(buf, "keep") != NULL);
 
Index: linux-3.4/include/linux/console.h
===================================================================
--- linux-3.4.orig/include/linux/console.h
+++ linux-3.4/include/linux/console.h
@@ -133,6 +133,7 @@ struct console {
 	for (con = console_drivers; con != NULL; con = con->next)
 
 extern int console_set_on_cmdline;
+extern struct console *early_console;
 
 extern int add_preferred_console(char *name, int idx, char *options);
 extern int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options);
Index: linux-3.4/include/linux/printk.h
===================================================================
--- linux-3.4.orig/include/linux/printk.h
+++ linux-3.4/include/linux/printk.h
@@ -88,8 +88,15 @@ int no_printk(const char *fmt, ...)
 	return 0;
 }
 
+#ifdef CONFIG_EARLY_PRINTK
 extern asmlinkage __printf(1, 2)
 void early_printk(const char *fmt, ...);
+extern void printk_kill(void);
+#else
+static inline __printf(1, 2) __cold
+void early_printk(const char *s, ...) { }
+static inline void printk_kill(void) { }
+#endif
 
 extern int printk_needs_cpu(int cpu);
 extern void printk_tick(void);
@@ -114,7 +121,6 @@ extern int __printk_ratelimit(const char
 #define printk_ratelimit() __printk_ratelimit(__func__)
 extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 				   unsigned int interval_msec);
-
 extern int printk_delay_msec;
 extern int dmesg_restrict;
 extern int kptr_restrict;
Index: linux-3.4/kernel/printk.c
===================================================================
--- linux-3.4.orig/kernel/printk.c
+++ linux-3.4/kernel/printk.c
@@ -21,6 +21,7 @@
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
 #include <linux/console.h>
+#include <linux/sysrq.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
 #include <linux/nmi.h>
@@ -47,13 +48,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/printk.h>
 
-/*
- * Architectures can override it:
- */
-void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
-{
-}
-
 #define __LOG_BUF_LEN	(1 << CONFIG_LOG_BUF_SHIFT)
 
 /* printk's without a loglevel use this.. */
@@ -514,6 +508,7 @@ static void __call_console_drivers(unsig
 {
 	struct console *con;
 
+	migrate_disable();
 	for_each_console(con) {
 		if (exclusive_console && con != exclusive_console)
 			continue;
@@ -522,8 +517,65 @@ static void __call_console_drivers(unsig
 				(con->flags & CON_ANYTIME)))
 			con->write(con, &LOG_BUF(start), end - start);
 	}
+	migrate_enable();
+}
+
+#ifdef CONFIG_EARLY_PRINTK
+struct console *early_console;
+
+static void early_vprintk(const char *fmt, va_list ap)
+{
+	if (early_console) {
+		char buf[512];
+		int n = vscnprintf(buf, sizeof(buf), fmt, ap);
+
+		early_console->write(early_console, buf, n);
+	}
+}
+
+asmlinkage void early_printk(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	early_vprintk(fmt, ap);
+	va_end(ap);
+}
+
+/*
+ * This is independent of any log levels - a global
+ * kill switch that turns off all of printk.
+ *
+ * Used by the NMI watchdog if early-printk is enabled.
+ */
+static bool __read_mostly printk_killswitch;
+
+static int __init force_early_printk_setup(char *str)
+{
+	printk_killswitch = true;
+	return 0;
+}
+early_param("force_early_printk", force_early_printk_setup);
+
+void printk_kill(void)
+{
+	printk_killswitch = true;
 }
 
+static int forced_early_printk(const char *fmt, va_list ap)
+{
+	if (!printk_killswitch)
+		return 0;
+	early_vprintk(fmt, ap);
+	return 1;
+}
+#else
+static inline int forced_early_printk(const char *fmt, va_list ap)
+{
+	return 0;
+}
+#endif
+
 static bool __read_mostly ignore_loglevel;
 
 static int __init ignore_loglevel_setup(char *str)
@@ -790,12 +842,18 @@ static inline int can_use_console(unsign
  * interrupts disabled. It should return with 'lockbuf_lock'
  * released but interrupts still disabled.
  */
-static int console_trylock_for_printk(unsigned int cpu)
+static int console_trylock_for_printk(unsigned int cpu, unsigned long flags)
 	__releases(&logbuf_lock)
 {
 	int retval = 0, wake = 0;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	int lock = (!early_boot_irqs_disabled && !irqs_disabled_flags(flags) &&
+		!preempt_count()) || sysrq_in_progress;
+#else
+	int lock = 1;
+#endif
 
-	if (console_trylock()) {
+	if (lock && console_trylock()) {
 		retval = 1;
 
 		/*
@@ -846,6 +904,13 @@ asmlinkage int vprintk(const char *fmt, 
 	size_t plen;
 	char special;
 
+	/*
+	 * Fall back to early_printk if a debugging subsystem has
+	 * killed printk output
+	 */
+	if (unlikely(forced_early_printk(fmt, args)))
+		return 1;
+
 	boot_delay_msec();
 	printk_delay();
 
@@ -965,8 +1030,15 @@ asmlinkage int vprintk(const char *fmt, 
 	 * will release 'logbuf_lock' regardless of whether it
 	 * actually gets the semaphore or not.
 	 */
-	if (console_trylock_for_printk(this_cpu))
+	if (console_trylock_for_printk(this_cpu, flags)) {
+#ifndef CONFIG_PREEMPT_RT_FULL
+		console_unlock();
+#else
+		raw_local_irq_restore(flags);
 		console_unlock();
+		raw_local_irq_save(flags);
+#endif
+	}
 
 	lockdep_on();
 out_restore_irqs:
@@ -1242,8 +1314,8 @@ void printk_tick(void)
 
 int printk_needs_cpu(int cpu)
 {
-	if (cpu_is_offline(cpu))
-		printk_tick();
+	if (unlikely(cpu_is_offline(cpu)))
+		__this_cpu_write(printk_pending, 0);
 	return __this_cpu_read(printk_pending);
 }
 
@@ -1289,11 +1361,16 @@ again:
 		_con_start = con_start;
 		_log_end = log_end;
 		con_start = log_end;		/* Flush */
+#ifndef CONFIG_PREEMPT_RT_FULL
 		raw_spin_unlock(&logbuf_lock);
 		stop_critical_timings();	/* don't trace print latency */
 		call_console_drivers(_con_start, _log_end);
 		start_critical_timings();
 		local_irq_restore(flags);
+#else
+		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+		call_console_drivers(_con_start, _log_end);
+#endif
 	}
 	console_locked = 0;
 
Index: linux-3.4/kernel/watchdog.c
===================================================================
--- linux-3.4.orig/kernel/watchdog.c
+++ linux-3.4/kernel/watchdog.c
@@ -201,6 +201,8 @@ static int is_softlockup(unsigned long t
 
 #ifdef CONFIG_HARDLOCKUP_DETECTOR
 
+static DEFINE_RAW_SPINLOCK(watchdog_output_lock);
+
 static struct perf_event_attr wd_hw_attr = {
 	.type		= PERF_TYPE_HARDWARE,
 	.config		= PERF_COUNT_HW_CPU_CYCLES,
@@ -235,10 +237,19 @@ static void watchdog_overflow_callback(s
 		if (__this_cpu_read(hard_watchdog_warn) == true)
 			return;
 
-		if (hardlockup_panic)
+		/*
+		 * If early-printk is enabled then make sure we do not
+		 * lock up in printk() and kill console logging:
+		 */
+		printk_kill();
+
+		if (hardlockup_panic) {
 			panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
-		else
+		} else {
+			raw_spin_lock(&watchdog_output_lock);
 			WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
+			raw_spin_unlock(&watchdog_output_lock);
+		}
 
 		__this_cpu_write(hard_watchdog_warn, true);
 		return;
@@ -430,6 +441,7 @@ static void watchdog_prepare_cpu(int cpu
 	WARN_ON(per_cpu(softlockup_watchdog, cpu));
 	hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	hrtimer->function = watchdog_timer_fn;
+	hrtimer->irqsafe = 1;
 }
 
 static int watchdog_enable(int cpu)
Index: linux-3.4/kernel/Kconfig.preempt
===================================================================
--- linux-3.4.orig/kernel/Kconfig.preempt
+++ linux-3.4/kernel/Kconfig.preempt
@@ -1,3 +1,10 @@
+config PREEMPT
+	bool
+	select PREEMPT_COUNT
+
+config PREEMPT_RT_BASE
+	bool
+	select PREEMPT
 
 choice
 	prompt "Preemption Model"
@@ -33,9 +40,9 @@ config PREEMPT_VOLUNTARY
 
 	  Select this if you are building a kernel for a desktop system.
 
-config PREEMPT
+config PREEMPT__LL
 	bool "Preemptible Kernel (Low-Latency Desktop)"
-	select PREEMPT_COUNT
+	select PREEMPT
 	select UNINLINE_SPIN_UNLOCK if !ARCH_INLINE_SPIN_UNLOCK
 	help
 	  This option reduces the latency of the kernel by making
@@ -52,6 +59,21 @@ config PREEMPT
 	  embedded system with latency requirements in the milliseconds
 	  range.
 
+config PREEMPT_RTB
+	bool "Preemptible Kernel (Basic RT)"
+	select PREEMPT_RT_BASE
+	help
+	  This option is basically the same as (Low-Latency Desktop) but
+	  enables changes which are preliminary for the full preemptiple
+	  RT kernel.
+
+config PREEMPT_RT_FULL
+	bool "Fully Preemptible Kernel (RT)"
+	depends on IRQ_FORCED_THREADING
+	select PREEMPT_RT_BASE
+	help
+	  All and everything
+
 endchoice
 
 config PREEMPT_COUNT
Index: linux-3.4/include/asm-generic/bug.h
===================================================================
--- linux-3.4.orig/include/asm-generic/bug.h
+++ linux-3.4/include/asm-generic/bug.h
@@ -3,6 +3,10 @@
 
 #include <linux/compiler.h>
 
+#ifndef __ASSEMBLY__
+extern void __WARN_ON(const char *func, const char *file, const int line);
+#endif /* __ASSEMBLY__ */
+
 #ifdef CONFIG_BUG
 
 #ifdef CONFIG_GENERIC_BUG
@@ -202,4 +206,18 @@ extern void warn_slowpath_null(const cha
 # define WARN_ON_SMP(x)			({0;})
 #endif
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+# define BUG_ON_RT(c)			BUG_ON(c)
+# define BUG_ON_NONRT(c)		do { } while (0)
+# define WARN_ON_RT(condition)		WARN_ON(condition)
+# define WARN_ON_NONRT(condition)	do { } while (0)
+# define WARN_ON_ONCE_NONRT(condition)	do { } while (0)
+#else
+# define BUG_ON_RT(c)			do { } while (0)
+# define BUG_ON_NONRT(c)		BUG_ON(c)
+# define WARN_ON_RT(condition)		do { } while (0)
+# define WARN_ON_NONRT(condition)	WARN_ON(condition)
+# define WARN_ON_ONCE_NONRT(condition)	WARN_ON_ONCE(condition)
+#endif
+
 #endif
Index: linux-3.4/include/linux/irqflags.h
===================================================================
--- linux-3.4.orig/include/linux/irqflags.h
+++ linux-3.4/include/linux/irqflags.h
@@ -25,8 +25,6 @@
 # define trace_softirqs_enabled(p)	((p)->softirqs_enabled)
 # define trace_hardirq_enter()	do { current->hardirq_context++; } while (0)
 # define trace_hardirq_exit()	do { current->hardirq_context--; } while (0)
-# define lockdep_softirq_enter()	do { current->softirq_context++; } while (0)
-# define lockdep_softirq_exit()	do { current->softirq_context--; } while (0)
 # define INIT_TRACE_IRQFLAGS	.softirqs_enabled = 1,
 #else
 # define trace_hardirqs_on()		do { } while (0)
@@ -39,9 +37,15 @@
 # define trace_softirqs_enabled(p)	0
 # define trace_hardirq_enter()		do { } while (0)
 # define trace_hardirq_exit()		do { } while (0)
+# define INIT_TRACE_IRQFLAGS
+#endif
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT_FULL)
+# define lockdep_softirq_enter() do { current->softirq_context++; } while (0)
+# define lockdep_softirq_exit()	 do { current->softirq_context--; } while (0)
+#else
 # define lockdep_softirq_enter()	do { } while (0)
 # define lockdep_softirq_exit()		do { } while (0)
-# define INIT_TRACE_IRQFLAGS
 #endif
 
 #if defined(CONFIG_IRQSOFF_TRACER) || \
@@ -147,4 +151,23 @@
 
 #endif /* CONFIG_TRACE_IRQFLAGS_SUPPORT */
 
+/*
+ * local_irq* variants depending on RT/!RT
+ */
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define local_irq_disable_nort()	do { } while (0)
+# define local_irq_enable_nort()	do { } while (0)
+# define local_irq_save_nort(flags)	do { local_save_flags(flags); } while (0)
+# define local_irq_restore_nort(flags)	do { (void)(flags); } while (0)
+# define local_irq_disable_rt()		local_irq_disable()
+# define local_irq_enable_rt()		local_irq_enable()
+#else
+# define local_irq_disable_nort()	local_irq_disable()
+# define local_irq_enable_nort()	local_irq_enable()
+# define local_irq_save_nort(flags)	local_irq_save(flags)
+# define local_irq_restore_nort(flags)	local_irq_restore(flags)
+# define local_irq_disable_rt()		do { } while (0)
+# define local_irq_enable_rt()		do { } while (0)
+#endif
+
 #endif
Index: linux-3.4/include/linux/preempt.h
===================================================================
--- linux-3.4.orig/include/linux/preempt.h
+++ linux-3.4/include/linux/preempt.h
@@ -54,11 +54,17 @@ do { \
 	dec_preempt_count(); \
 } while (0)
 
-#define preempt_enable_no_resched()	sched_preempt_enable_no_resched()
+#ifndef CONFIG_PREEMPT_RT_BASE
+# define preempt_enable_no_resched()	sched_preempt_enable_no_resched()
+# define preempt_check_resched_rt()	do { } while (0)
+#else
+# define preempt_enable_no_resched()	preempt_enable()
+# define preempt_check_resched_rt()	preempt_check_resched()
+#endif
 
 #define preempt_enable() \
 do { \
-	preempt_enable_no_resched(); \
+	sched_preempt_enable_no_resched(); \
 	barrier(); \
 	preempt_check_resched(); \
 } while (0)
@@ -101,9 +107,31 @@ do { \
 #define preempt_disable_notrace()		do { } while (0)
 #define preempt_enable_no_resched_notrace()	do { } while (0)
 #define preempt_enable_notrace()		do { } while (0)
+#define preempt_check_resched_rt()	do { } while (0)
 
 #endif /* CONFIG_PREEMPT_COUNT */
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define preempt_disable_rt()		preempt_disable()
+# define preempt_enable_rt()		preempt_enable()
+# define preempt_disable_nort()		do { } while (0)
+# define preempt_enable_nort()		do { } while (0)
+# ifdef CONFIG_SMP
+   extern void migrate_disable(void);
+   extern void migrate_enable(void);
+# else /* CONFIG_SMP */
+#  define migrate_disable()		do { } while (0)
+#  define migrate_enable()		do { } while (0)
+# endif /* CONFIG_SMP */
+#else
+# define preempt_disable_rt()		do { } while (0)
+# define preempt_enable_rt()		do { } while (0)
+# define preempt_disable_nort()		preempt_disable()
+# define preempt_enable_nort()		preempt_enable()
+# define migrate_disable()		preempt_disable()
+# define migrate_enable()		preempt_enable()
+#endif
+
 #ifdef CONFIG_PREEMPT_NOTIFIERS
 
 struct preempt_notifier;
Index: linux-3.4/drivers/ata/libata-sff.c
===================================================================
--- linux-3.4.orig/drivers/ata/libata-sff.c
+++ linux-3.4/drivers/ata/libata-sff.c
@@ -678,9 +678,9 @@ unsigned int ata_sff_data_xfer_noirq(str
 	unsigned long flags;
 	unsigned int consumed;
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	consumed = ata_sff_data_xfer32(dev, buf, buflen, rw);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 
 	return consumed;
 }
@@ -719,7 +719,7 @@ static void ata_pio_sector(struct ata_qu
 		unsigned long flags;
 
 		/* FIXME: use a bounce buffer */
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		buf = kmap_atomic(page);
 
 		/* do the actual data transfer */
@@ -727,7 +727,7 @@ static void ata_pio_sector(struct ata_qu
 				       do_write);
 
 		kunmap_atomic(buf);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 	} else {
 		buf = page_address(page);
 		ap->ops->sff_data_xfer(qc->dev, buf + offset, qc->sect_size,
@@ -864,7 +864,7 @@ next_sg:
 		unsigned long flags;
 
 		/* FIXME: use bounce buffer */
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		buf = kmap_atomic(page);
 
 		/* do the actual data transfer */
@@ -872,7 +872,7 @@ next_sg:
 								count, rw);
 
 		kunmap_atomic(buf);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 	} else {
 		buf = page_address(page);
 		consumed = ap->ops->sff_data_xfer(dev,  buf + offset,
Index: linux-3.4/drivers/ide/alim15x3.c
===================================================================
--- linux-3.4.orig/drivers/ide/alim15x3.c
+++ linux-3.4/drivers/ide/alim15x3.c
@@ -234,7 +234,7 @@ static int init_chipset_ali15x3(struct p
 
 	isa_dev = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 
 	if (m5229_revision < 0xC2) {
 		/*
@@ -325,7 +325,7 @@ out:
 	}
 	pci_dev_put(north);
 	pci_dev_put(isa_dev);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 	return 0;
 }
 
Index: linux-3.4/drivers/ide/hpt366.c
===================================================================
--- linux-3.4.orig/drivers/ide/hpt366.c
+++ linux-3.4/drivers/ide/hpt366.c
@@ -1241,7 +1241,7 @@ static int __devinit init_dma_hpt366(ide
 
 	dma_old = inb(base + 2);
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 
 	dma_new = dma_old;
 	pci_read_config_byte(dev, hwif->channel ? 0x4b : 0x43, &masterdma);
@@ -1252,7 +1252,7 @@ static int __devinit init_dma_hpt366(ide
 	if (dma_new != dma_old)
 		outb(dma_new, base + 2);
 
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 
 	printk(KERN_INFO "    %s: BM-DMA at 0x%04lx-0x%04lx\n",
 			 hwif->name, base, base + 7);
Index: linux-3.4/drivers/ide/ide-io-std.c
===================================================================
--- linux-3.4.orig/drivers/ide/ide-io-std.c
+++ linux-3.4/drivers/ide/ide-io-std.c
@@ -175,7 +175,7 @@ void ide_input_data(ide_drive_t *drive, 
 		unsigned long uninitialized_var(flags);
 
 		if ((io_32bit & 2) && !mmio) {
-			local_irq_save(flags);
+			local_irq_save_nort(flags);
 			ata_vlb_sync(io_ports->nsect_addr);
 		}
 
@@ -186,7 +186,7 @@ void ide_input_data(ide_drive_t *drive, 
 			insl(data_addr, buf, words);
 
 		if ((io_32bit & 2) && !mmio)
-			local_irq_restore(flags);
+			local_irq_restore_nort(flags);
 
 		if (((len + 1) & 3) < 2)
 			return;
@@ -219,7 +219,7 @@ void ide_output_data(ide_drive_t *drive,
 		unsigned long uninitialized_var(flags);
 
 		if ((io_32bit & 2) && !mmio) {
-			local_irq_save(flags);
+			local_irq_save_nort(flags);
 			ata_vlb_sync(io_ports->nsect_addr);
 		}
 
@@ -230,7 +230,7 @@ void ide_output_data(ide_drive_t *drive,
 			outsl(data_addr, buf, words);
 
 		if ((io_32bit & 2) && !mmio)
-			local_irq_restore(flags);
+			local_irq_restore_nort(flags);
 
 		if (((len + 1) & 3) < 2)
 			return;
Index: linux-3.4/drivers/ide/ide-io.c
===================================================================
--- linux-3.4.orig/drivers/ide/ide-io.c
+++ linux-3.4/drivers/ide/ide-io.c
@@ -659,7 +659,7 @@ void ide_timer_expiry (unsigned long dat
 		/* disable_irq_nosync ?? */
 		disable_irq(hwif->irq);
 		/* local CPU only, as if we were handling an interrupt */
-		local_irq_disable();
+		local_irq_disable_nort();
 		if (hwif->polling) {
 			startstop = handler(drive);
 		} else if (drive_is_ready(drive)) {
Index: linux-3.4/drivers/ide/ide-iops.c
===================================================================
--- linux-3.4.orig/drivers/ide/ide-iops.c
+++ linux-3.4/drivers/ide/ide-iops.c
@@ -129,12 +129,12 @@ int __ide_wait_stat(ide_drive_t *drive, 
 				if ((stat & ATA_BUSY) == 0)
 					break;
 
-				local_irq_restore(flags);
+				local_irq_restore_nort(flags);
 				*rstat = stat;
 				return -EBUSY;
 			}
 		}
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 	}
 	/*
 	 * Allow status to settle, then read it again.
Index: linux-3.4/drivers/ide/ide-probe.c
===================================================================
--- linux-3.4.orig/drivers/ide/ide-probe.c
+++ linux-3.4/drivers/ide/ide-probe.c
@@ -196,10 +196,10 @@ static void do_identify(ide_drive_t *dri
 	int bswap = 1;
 
 	/* local CPU only; some systems need this */
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	/* read 512 bytes of id info */
 	hwif->tp_ops->input_data(drive, NULL, id, SECTOR_SIZE);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 
 	drive->dev_flags |= IDE_DFLAG_ID_READ;
 #ifdef DEBUG
Index: linux-3.4/drivers/ide/ide-taskfile.c
===================================================================
--- linux-3.4.orig/drivers/ide/ide-taskfile.c
+++ linux-3.4/drivers/ide/ide-taskfile.c
@@ -251,7 +251,7 @@ void ide_pio_bytes(ide_drive_t *drive, s
 
 		page_is_high = PageHighMem(page);
 		if (page_is_high)
-			local_irq_save(flags);
+			local_irq_save_nort(flags);
 
 		buf = kmap_atomic(page) + offset;
 
@@ -272,7 +272,7 @@ void ide_pio_bytes(ide_drive_t *drive, s
 		kunmap_atomic(buf);
 
 		if (page_is_high)
-			local_irq_restore(flags);
+			local_irq_restore_nort(flags);
 
 		len -= nr_bytes;
 	}
@@ -415,7 +415,7 @@ static ide_startstop_t pre_task_out_intr
 	}
 
 	if ((drive->dev_flags & IDE_DFLAG_UNMASK) == 0)
-		local_irq_disable();
+		local_irq_disable_nort();
 
 	ide_set_handler(drive, &task_pio_intr, WAIT_WORSTCASE);
 
Index: linux-3.4/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
===================================================================
--- linux-3.4.orig/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ linux-3.4/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -798,7 +798,7 @@ void ipoib_mcast_restart_task(struct wor
 
 	ipoib_mcast_stop_thread(dev, 0);
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	netif_addr_lock(dev);
 	spin_lock(&priv->lock);
 
@@ -880,7 +880,7 @@ void ipoib_mcast_restart_task(struct wor
 
 	spin_unlock(&priv->lock);
 	netif_addr_unlock(dev);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 
 	/* We have to cancel outside of the spinlock */
 	list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
Index: linux-3.4/drivers/input/gameport/gameport.c
===================================================================
--- linux-3.4.orig/drivers/input/gameport/gameport.c
+++ linux-3.4/drivers/input/gameport/gameport.c
@@ -87,12 +87,12 @@ static int gameport_measure_speed(struct
 	tx = 1 << 30;
 
 	for(i = 0; i < 50; i++) {
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		GET_TIME(t1);
 		for (t = 0; t < 50; t++) gameport_read(gameport);
 		GET_TIME(t2);
 		GET_TIME(t3);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 		udelay(i * 10);
 		if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 	}
@@ -111,11 +111,11 @@ static int gameport_measure_speed(struct
 	tx = 1 << 30;
 
 	for(i = 0; i < 50; i++) {
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		rdtscl(t1);
 		for (t = 0; t < 50; t++) gameport_read(gameport);
 		rdtscl(t2);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 		udelay(i * 10);
 		if (t2 - t1 < tx) tx = t2 - t1;
 	}
Index: linux-3.4/arch/x86/include/asm/acpi.h
===================================================================
--- linux-3.4.orig/arch/x86/include/asm/acpi.h
+++ linux-3.4/arch/x86/include/asm/acpi.h
@@ -51,8 +51,8 @@
 
 #define ACPI_ASM_MACROS
 #define BREAKPOINT3
-#define ACPI_DISABLE_IRQS() local_irq_disable()
-#define ACPI_ENABLE_IRQS()  local_irq_enable()
+#define ACPI_DISABLE_IRQS() local_irq_disable_nort()
+#define ACPI_ENABLE_IRQS()  local_irq_enable_nort()
 #define ACPI_FLUSH_CPU_CACHE()	wbinvd()
 
 int __acpi_acquire_global_lock(unsigned int *lock);
Index: linux-3.4/kernel/user.c
===================================================================
--- linux-3.4.orig/kernel/user.c
+++ linux-3.4/kernel/user.c
@@ -129,11 +129,11 @@ void free_uid(struct user_struct *up)
 	if (!up)
 		return;
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
 		free_user(up, flags);
 	else
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 }
 
 struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
Index: linux-3.4/kernel/res_counter.c
===================================================================
--- linux-3.4.orig/kernel/res_counter.c
+++ linux-3.4/kernel/res_counter.c
@@ -43,7 +43,7 @@ int res_counter_charge(struct res_counte
 	struct res_counter *c, *u;
 
 	*limit_fail_at = NULL;
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	for (c = counter; c != NULL; c = c->parent) {
 		spin_lock(&c->lock);
 		ret = res_counter_charge_locked(c, val);
@@ -62,7 +62,7 @@ undo:
 		spin_unlock(&u->lock);
 	}
 done:
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 	return ret;
 }
 
@@ -104,13 +104,13 @@ void res_counter_uncharge(struct res_cou
 	unsigned long flags;
 	struct res_counter *c;
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	for (c = counter; c != NULL; c = c->parent) {
 		spin_lock(&c->lock);
 		res_counter_uncharge_locked(c, val);
 		spin_unlock(&c->lock);
 	}
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 }
 
 
Index: linux-3.4/drivers/usb/core/hcd.c
===================================================================
--- linux-3.4.orig/drivers/usb/core/hcd.c
+++ linux-3.4/drivers/usb/core/hcd.c
@@ -2143,7 +2143,7 @@ irqreturn_t usb_hcd_irq (int irq, void *
 	 * when the first handler doesn't use it.  So let's just
 	 * assume it's never used.
 	 */
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 
 	if (unlikely(HCD_DEAD(hcd) || !HCD_HW_ACCESSIBLE(hcd)))
 		rc = IRQ_NONE;
@@ -2152,7 +2152,7 @@ irqreturn_t usb_hcd_irq (int irq, void *
 	else
 		rc = IRQ_HANDLED;
 
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(usb_hcd_irq);
Index: linux-3.4/drivers/tty/tty_ldisc.c
===================================================================
--- linux-3.4.orig/drivers/tty/tty_ldisc.c
+++ linux-3.4/drivers/tty/tty_ldisc.c
@@ -53,7 +53,7 @@ static void put_ldisc(struct tty_ldisc *
 	 * We really want an "atomic_dec_and_lock_irqsave()",
 	 * but we don't have it, so this does it by hand.
 	 */
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	if (atomic_dec_and_lock(&ld->users, &tty_ldisc_lock)) {
 		struct tty_ldisc_ops *ldo = ld->ops;
 
@@ -64,7 +64,7 @@ static void put_ldisc(struct tty_ldisc *
 		kfree(ld);
 		return;
 	}
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 	wake_up(&tty_ldisc_idle);
 }
 
Index: linux-3.4/lib/scatterlist.c
===================================================================
--- linux-3.4.orig/lib/scatterlist.c
+++ linux-3.4/lib/scatterlist.c
@@ -423,7 +423,7 @@ void sg_miter_stop(struct sg_mapping_ite
 			flush_kernel_dcache_page(miter->page);
 
 		if (miter->__flags & SG_MITER_ATOMIC) {
-			WARN_ON(!irqs_disabled());
+			WARN_ON_NONRT(!irqs_disabled());
 			kunmap_atomic(miter->addr);
 		} else
 			kunmap(miter->page);
@@ -463,7 +463,7 @@ static size_t sg_copy_buffer(struct scat
 
 	sg_miter_start(&miter, sgl, nents, sg_flags);
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 
 	while (sg_miter_next(&miter) && offset < buflen) {
 		unsigned int len;
@@ -480,7 +480,7 @@ static size_t sg_copy_buffer(struct scat
 
 	sg_miter_stop(&miter);
 
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 	return offset;
 }
 
Index: linux-3.4/net/mac80211/rx.c
===================================================================
--- linux-3.4.orig/net/mac80211/rx.c
+++ linux-3.4/net/mac80211/rx.c
@@ -3015,7 +3015,7 @@ void ieee80211_rx(struct ieee80211_hw *h
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 
-	WARN_ON_ONCE(softirq_count() == 0);
+	WARN_ON_ONCE_NONRT(softirq_count() == 0);
 
 	if (WARN_ON(status->band < 0 ||
 		    status->band >= IEEE80211_NUM_BANDS))
Index: linux-3.4/include/linux/page_cgroup.h
===================================================================
--- linux-3.4.orig/include/linux/page_cgroup.h
+++ linux-3.4/include/linux/page_cgroup.h
@@ -24,6 +24,9 @@ enum {
  */
 struct page_cgroup {
 	unsigned long flags;
+#ifdef CONFIG_PREEMPT_RT_BASE
+	spinlock_t pcg_lock;
+#endif
 	struct mem_cgroup *mem_cgroup;
 };
 
@@ -74,12 +77,20 @@ static inline void lock_page_cgroup(stru
 	 * Don't take this lock in IRQ context.
 	 * This lock is for pc->mem_cgroup, USED, MIGRATION
 	 */
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_lock(PCG_LOCK, &pc->flags);
+#else
+	spin_lock(&pc->pcg_lock);
+#endif
 }
 
 static inline void unlock_page_cgroup(struct page_cgroup *pc)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_unlock(PCG_LOCK, &pc->flags);
+#else
+	spin_unlock(&pc->pcg_lock);
+#endif
 }
 
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
@@ -102,6 +113,10 @@ static inline void __init page_cgroup_in
 {
 }
 
+static inline void page_cgroup_lock_init(struct page_cgroup *pc)
+{
+}
+
 #endif /* CONFIG_CGROUP_MEM_RES_CTLR */
 
 #include <linux/swap.h>
Index: linux-3.4/mm/page_cgroup.c
===================================================================
--- linux-3.4.orig/mm/page_cgroup.c
+++ linux-3.4/mm/page_cgroup.c
@@ -13,6 +13,14 @@
 
 static unsigned long total_usage;
 
+static void page_cgroup_lock_init(struct page_cgroup *pc, int nr_pages)
+{
+#ifdef CONFIG_PREEMPT_RT_BASE
+	for (; nr_pages; nr_pages--, pc++)
+		spin_lock_init(&pc->pcg_lock);
+#endif
+}
+
 #if !defined(CONFIG_SPARSEMEM)
 
 
@@ -60,6 +68,7 @@ static int __init alloc_node_page_cgroup
 		return -ENOMEM;
 	NODE_DATA(nid)->node_page_cgroup = base;
 	total_usage += table_size;
+	page_cgroup_lock_init(base, nr_pages);
 	return 0;
 }
 
@@ -150,6 +159,8 @@ static int __meminit init_section_page_c
 		return -ENOMEM;
 	}
 
+	page_cgroup_lock_init(base, PAGES_PER_SECTION);
+
 	/*
 	 * The passed "pfn" may not be aligned to SECTION.  For the calculation
 	 * we need to apply a mask.
Index: linux-3.4/fs/buffer.c
===================================================================
--- linux-3.4.orig/fs/buffer.c
+++ linux-3.4/fs/buffer.c
@@ -281,8 +281,7 @@ static void end_buffer_async_read(struct
 	 * decide that the page is now completely done.
 	 */
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	flags = bh_uptodate_lock_irqsave(first);
 	clear_buffer_async_read(bh);
 	unlock_buffer(bh);
 	tmp = bh;
@@ -295,8 +294,7 @@ static void end_buffer_async_read(struct
 		}
 		tmp = tmp->b_this_page;
 	} while (tmp != bh);
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	bh_uptodate_unlock_irqrestore(first, flags);
 
 	/*
 	 * If none of the buffers had errors and they are all
@@ -308,9 +306,7 @@ static void end_buffer_async_read(struct
 	return;
 
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
-	return;
+	bh_uptodate_unlock_irqrestore(first, flags);
 }
 
 /*
@@ -344,8 +340,7 @@ void end_buffer_async_write(struct buffe
 	}
 
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	flags = bh_uptodate_lock_irqsave(first);
 
 	clear_buffer_async_write(bh);
 	unlock_buffer(bh);
@@ -357,15 +352,12 @@ void end_buffer_async_write(struct buffe
 		}
 		tmp = tmp->b_this_page;
 	}
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	bh_uptodate_unlock_irqrestore(first, flags);
 	end_page_writeback(page);
 	return;
 
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
-	return;
+	bh_uptodate_unlock_irqrestore(first, flags);
 }
 EXPORT_SYMBOL(end_buffer_async_write);
 
@@ -3185,6 +3177,7 @@ struct buffer_head *alloc_buffer_head(gf
 	struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
 	if (ret) {
 		INIT_LIST_HEAD(&ret->b_assoc_buffers);
+		buffer_head_init_locks(ret);
 		preempt_disable();
 		__this_cpu_inc(bh_accounting.nr);
 		recalc_bh_state();
Index: linux-3.4/fs/ntfs/aops.c
===================================================================
--- linux-3.4.orig/fs/ntfs/aops.c
+++ linux-3.4/fs/ntfs/aops.c
@@ -108,8 +108,7 @@ static void ntfs_end_buffer_async_read(s
 				"0x%llx.", (unsigned long long)bh->b_blocknr);
 	}
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	flags = bh_uptodate_lock_irqsave(first);
 	clear_buffer_async_read(bh);
 	unlock_buffer(bh);
 	tmp = bh;
@@ -124,8 +123,7 @@ static void ntfs_end_buffer_async_read(s
 		}
 		tmp = tmp->b_this_page;
 	} while (tmp != bh);
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	bh_uptodate_unlock_irqrestore(first, flags);
 	/*
 	 * If none of the buffers had errors then we can set the page uptodate,
 	 * but we first have to perform the post read mst fixups, if the
@@ -146,13 +144,13 @@ static void ntfs_end_buffer_async_read(s
 		recs = PAGE_CACHE_SIZE / rec_size;
 		/* Should have been verified before we got here... */
 		BUG_ON(!recs);
-		local_irq_save(flags);
+		local_irq_save_nort(flags);
 		kaddr = kmap_atomic(page);
 		for (i = 0; i < recs; i++)
 			post_read_mst_fixup((NTFS_RECORD*)(kaddr +
 					i * rec_size), rec_size);
 		kunmap_atomic(kaddr);
-		local_irq_restore(flags);
+		local_irq_restore_nort(flags);
 		flush_dcache_page(page);
 		if (likely(page_uptodate && !PageError(page)))
 			SetPageUptodate(page);
@@ -160,9 +158,7 @@ static void ntfs_end_buffer_async_read(s
 	unlock_page(page);
 	return;
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
-	return;
+	bh_uptodate_unlock_irqrestore(first, flags);
 }
 
 /**
Index: linux-3.4/include/linux/buffer_head.h
===================================================================
--- linux-3.4.orig/include/linux/buffer_head.h
+++ linux-3.4/include/linux/buffer_head.h
@@ -72,8 +72,52 @@ struct buffer_head {
 	struct address_space *b_assoc_map;	/* mapping this buffer is
 						   associated with */
 	atomic_t b_count;		/* users using this buffer_head */
+#ifdef CONFIG_PREEMPT_RT_BASE
+	spinlock_t b_uptodate_lock;
+#if defined(CONFIG_JBD) || defined(CONFIG_JBD_MODULE) || \
+    defined(CONFIG_JBD2) || defined(CONFIG_JBD2_MODULE)
+	spinlock_t b_state_lock;
+	spinlock_t b_journal_head_lock;
+#endif
+#endif
 };
 
+static inline unsigned long bh_uptodate_lock_irqsave(struct buffer_head *bh)
+{
+	unsigned long flags;
+
+#ifndef CONFIG_PREEMPT_RT_BASE
+	local_irq_save(flags);
+	bit_spin_lock(BH_Uptodate_Lock, &bh->b_state);
+#else
+	spin_lock_irqsave(&bh->b_uptodate_lock, flags);
+#endif
+	return flags;
+}
+
+static inline void
+bh_uptodate_unlock_irqrestore(struct buffer_head *bh, unsigned long flags)
+{
+#ifndef CONFIG_PREEMPT_RT_BASE
+	bit_spin_unlock(BH_Uptodate_Lock, &bh->b_state);
+	local_irq_restore(flags);
+#else
+	spin_unlock_irqrestore(&bh->b_uptodate_lock, flags);
+#endif
+}
+
+static inline void buffer_head_init_locks(struct buffer_head *bh)
+{
+#ifdef CONFIG_PREEMPT_RT_BASE
+	spin_lock_init(&bh->b_uptodate_lock);
+#if defined(CONFIG_JBD) || defined(CONFIG_JBD_MODULE) || \
+    defined(CONFIG_JBD2) || defined(CONFIG_JBD2_MODULE)
+	spin_lock_init(&bh->b_state_lock);
+	spin_lock_init(&bh->b_journal_head_lock);
+#endif
+#endif
+}
+
 /*
  * macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
  * and buffer_foo() functions.
Index: linux-3.4/include/linux/jbd_common.h
===================================================================
--- linux-3.4.orig/include/linux/jbd_common.h
+++ linux-3.4/include/linux/jbd_common.h
@@ -37,32 +37,56 @@ static inline struct journal_head *bh2jh
 
 static inline void jbd_lock_bh_state(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_lock(BH_State, &bh->b_state);
+#else
+	spin_lock(&bh->b_state_lock);
+#endif
 }
 
 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	return bit_spin_trylock(BH_State, &bh->b_state);
+#else
+	return spin_trylock(&bh->b_state_lock);
+#endif
 }
 
 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	return bit_spin_is_locked(BH_State, &bh->b_state);
+#else
+	return spin_is_locked(&bh->b_state_lock);
+#endif
 }
 
 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_unlock(BH_State, &bh->b_state);
+#else
+	spin_unlock(&bh->b_state_lock);
+#endif
 }
 
 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_lock(BH_JournalHead, &bh->b_state);
+#else
+	spin_lock(&bh->b_journal_head_lock);
+#endif
 }
 
 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	bit_spin_unlock(BH_JournalHead, &bh->b_state);
+#else
+	spin_unlock(&bh->b_journal_head_lock);
+#endif
 }
 
 #endif
Index: linux-3.4/lib/Kconfig.debug
===================================================================
--- linux-3.4.orig/lib/Kconfig.debug
+++ linux-3.4/lib/Kconfig.debug
@@ -62,6 +62,28 @@ config MAGIC_SYSRQ
 	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
 	  unless you really know what this hack does.
 
+config MAGIC_SYSRQ_FORCE_PRINTK
+	bool "Force printk from Magic SysRq"
+	depends on MAGIC_SYSRQ && PREEMPT_RT_FULL
+	default n
+	help
+	  Allow the output from Magic SysRq to be output immediately, even if
+	  this causes large latencies.  This can cause performance problems
+	  for real-time processes.
+
+	  If PREEMPT_RT_FULL, printk() will not try to acquire the console lock
+	  when interrupts or preemption are disabled.  If the console lock is
+	  not acquired the printk() output will be buffered, but will not be
+	  output immediately.  Some drivers call into the Magic SysRq code
+	  with interrupts or preemption disabled, so the output of Magic SysRq
+	  will be buffered instead of printing immediately if this option is
+	  not selected.
+
+	  Even with this option selected, Magic SysRq output will be delayed
+	  if the attempt to acquire the console lock fails.
+
+	  Don't say Y unless you really know what this hack does.
+
 config STRIP_ASM_SYMS
 	bool "Strip assembler-generated symbols during link"
 	default n
@@ -151,7 +173,7 @@ config DEBUG_KERNEL
 
 config DEBUG_SHIRQ
 	bool "Debug shared IRQ handlers"
-	depends on DEBUG_KERNEL && GENERIC_HARDIRQS
+	depends on DEBUG_KERNEL && GENERIC_HARDIRQS && !PREEMPT_RT_BASE
 	help
 	  Enable this to generate a spurious interrupt as soon as a shared
 	  interrupt handler is registered, and just before one is deregistered.
Index: linux-3.4/kernel/irq/handle.c
===================================================================
--- linux-3.4.orig/kernel/irq/handle.c
+++ linux-3.4/kernel/irq/handle.c
@@ -172,8 +172,11 @@ handle_irq_event_percpu(struct irq_desc 
 		action = action->next;
 	} while (action);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+	/* FIXME: Can we unbreak that ? */
 	if (random & IRQF_SAMPLE_RANDOM)
 		add_interrupt_randomness(irq);
+#endif
 
 	if (!noirqdebug)
 		note_interrupt(irq, desc, retval);
Index: linux-3.4/kernel/irq/spurious.c
===================================================================
--- linux-3.4.orig/kernel/irq/spurious.c
+++ linux-3.4/kernel/irq/spurious.c
@@ -341,6 +341,11 @@ MODULE_PARM_DESC(noirqdebug, "Disable ir
 
 static int __init irqfixup_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT_BASE
+	printk(KERN_WARNING "irqfixup boot option not supported "
+		"w/ CONFIG_PREEMPT_RT\n");
+	return 1;
+#endif
 	irqfixup = 1;
 	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 	printk(KERN_WARNING "This may impact system performance.\n");
@@ -353,6 +358,11 @@ module_param(irqfixup, int, 0644);
 
 static int __init irqpoll_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT_BASE
+	printk(KERN_WARNING "irqpoll boot option not supported "
+		"w/ CONFIG_PREEMPT_RT\n");
+	return 1;
+#endif
 	irqfixup = 2;
 	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 				"enabled\n");
Index: linux-3.4/kernel/irq/manage.c
===================================================================
--- linux-3.4.orig/kernel/irq/manage.c
+++ linux-3.4/kernel/irq/manage.c
@@ -18,6 +18,7 @@
 #include "internals.h"
 
 #ifdef CONFIG_IRQ_FORCED_THREADING
+# ifndef CONFIG_PREEMPT_RT_BASE
 __read_mostly bool force_irqthreads;
 
 static int __init setup_forced_irqthreads(char *arg)
@@ -26,6 +27,7 @@ static int __init setup_forced_irqthread
 	return 0;
 }
 early_param("threadirqs", setup_forced_irqthreads);
+# endif
 #endif
 
 /**
@@ -747,7 +749,15 @@ irq_forced_thread_fn(struct irq_desc *de
 	local_bh_disable();
 	ret = action->thread_fn(action->irq, action->dev_id);
 	irq_finalize_oneshot(desc, action);
-	local_bh_enable();
+	/*
+	 * Interrupts which have real time requirements can be set up
+	 * to avoid softirq processing in the thread handler. This is
+	 * safe as these interrupts do not raise soft interrupts.
+	 */
+	if (irq_settings_no_softirq_call(desc))
+		_local_bh_enable();
+	else
+		local_bh_enable();
 	return ret;
 }
 
@@ -1069,6 +1079,9 @@ __setup_irq(unsigned int irq, struct irq
 			irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
 		}
 
+		if (new->flags & IRQF_NO_SOFTIRQ_CALL)
+			irq_settings_set_no_softirq_call(desc);
+
 		/* Set default affinity mask once everything is setup */
 		setup_affinity(irq, desc, mask);
 
Index: linux-3.4/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ linux-3.4/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
@@ -2240,11 +2240,7 @@ static netdev_tx_t atl1c_xmit_frame(stru
 	}
 
 	tpd_req = atl1c_cal_tpd_req(skb);
-	if (!spin_trylock_irqsave(&adapter->tx_lock, flags)) {
-		if (netif_msg_pktdata(adapter))
-			dev_info(&adapter->pdev->dev, "tx locked\n");
-		return NETDEV_TX_LOCKED;
-	}
+	spin_lock_irqsave(&adapter->tx_lock, flags);
 
 	if (atl1c_tpd_avail(adapter, type) < tpd_req) {
 		/* no enough descriptor, just stop queue */
Index: linux-3.4/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
+++ linux-3.4/drivers/net/ethernet/atheros/atl1e/atl1e_main.c
@@ -1822,8 +1822,7 @@ static netdev_tx_t atl1e_xmit_frame(stru
 		return NETDEV_TX_OK;
 	}
 	tpd_req = atl1e_cal_tdp_req(skb);
-	if (!spin_trylock_irqsave(&adapter->tx_lock, flags))
-		return NETDEV_TX_LOCKED;
+	spin_lock_irqsave(&adapter->tx_lock, flags);
 
 	if (atl1e_tpd_avail(adapter) < tpd_req) {
 		/* no enough descriptor, just stop queue */
Index: linux-3.4/drivers/net/ethernet/chelsio/cxgb/sge.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/chelsio/cxgb/sge.c
+++ linux-3.4/drivers/net/ethernet/chelsio/cxgb/sge.c
@@ -1678,8 +1678,7 @@ static int t1_sge_tx(struct sk_buff *skb
 	struct cmdQ *q = &sge->cmdQ[qid];
 	unsigned int credits, pidx, genbit, count, use_sched_skb = 0;
 
-	if (!spin_trylock(&q->lock))
-		return NETDEV_TX_LOCKED;
+	spin_lock(&q->lock);
 
 	reclaim_completed_tx(sge, q);
 
Index: linux-3.4/drivers/net/ethernet/neterion/s2io.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/neterion/s2io.c
+++ linux-3.4/drivers/net/ethernet/neterion/s2io.c
@@ -4089,12 +4089,7 @@ static netdev_tx_t s2io_xmit(struct sk_b
 			[skb->priority & (MAX_TX_FIFOS - 1)];
 	fifo = &mac_control->fifos[queue];
 
-	if (do_spin_lock)
-		spin_lock_irqsave(&fifo->tx_lock, flags);
-	else {
-		if (unlikely(!spin_trylock_irqsave(&fifo->tx_lock, flags)))
-			return NETDEV_TX_LOCKED;
-	}
+	spin_lock_irqsave(&fifo->tx_lock, flags);
 
 	if (sp->config.multiq) {
 		if (__netif_subqueue_stopped(dev, fifo->fifo_no)) {
Index: linux-3.4/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+++ linux-3.4/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
@@ -2131,10 +2131,9 @@ static int pch_gbe_xmit_frame(struct sk_
 		adapter->stats.tx_length_errors++;
 		return NETDEV_TX_OK;
 	}
-	if (!spin_trylock_irqsave(&tx_ring->tx_lock, flags)) {
-		/* Collision - tell upper layer to requeue */
-		return NETDEV_TX_LOCKED;
-	}
+
+	spin_lock_irqsave(&tx_ring->tx_lock, flags);
+
 	if (unlikely(!PCH_GBE_DESC_UNUSED(tx_ring))) {
 		netif_stop_queue(netdev);
 		spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
Index: linux-3.4/drivers/net/ethernet/tehuti/tehuti.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/tehuti/tehuti.c
+++ linux-3.4/drivers/net/ethernet/tehuti/tehuti.c
@@ -1606,13 +1606,8 @@ static netdev_tx_t bdx_tx_transmit(struc
 	unsigned long flags;
 
 	ENTER;
-	local_irq_save(flags);
-	if (!spin_trylock(&priv->tx_lock)) {
-		local_irq_restore(flags);
-		DBG("%s[%s]: TX locked, returning NETDEV_TX_LOCKED\n",
-		    BDX_DRV_NAME, ndev->name);
-		return NETDEV_TX_LOCKED;
-	}
+
+	spin_lock_irqsave(&priv->tx_lock, flags);
 
 	/* build tx descriptor */
 	BDX_ASSERT(f->m.wptr >= f->m.memsz);	/* started with valid wptr */
Index: linux-3.4/drivers/net/rionet.c
===================================================================
--- linux-3.4.orig/drivers/net/rionet.c
+++ linux-3.4/drivers/net/rionet.c
@@ -176,11 +176,7 @@ static int rionet_start_xmit(struct sk_b
 	u16 destid;
 	unsigned long flags;
 
-	local_irq_save(flags);
-	if (!spin_trylock(&rnet->tx_lock)) {
-		local_irq_restore(flags);
-		return NETDEV_TX_LOCKED;
-	}
+	spin_lock_irqsave(&rnet->tx_lock, flags);
 
 	if ((rnet->tx_cnt + 1) > RIONET_TX_RING_SIZE) {
 		netif_stop_queue(ndev);
Index: linux-3.4/drivers/net/ethernet/3com/3c59x.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/3com/3c59x.c
+++ linux-3.4/drivers/net/ethernet/3com/3c59x.c
@@ -843,9 +843,9 @@ static void poll_vortex(struct net_devic
 {
 	struct vortex_private *vp = netdev_priv(dev);
 	unsigned long flags;
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	(vp->full_bus_master_rx ? boomerang_interrupt:vortex_interrupt)(dev->irq,dev);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 }
 #endif
 
@@ -1920,12 +1920,12 @@ static void vortex_tx_timeout(struct net
 			 * Block interrupts because vortex_interrupt does a bare spin_lock()
 			 */
 			unsigned long flags;
-			local_irq_save(flags);
+			local_irq_save_nort(flags);
 			if (vp->full_bus_master_tx)
 				boomerang_interrupt(dev->irq, dev);
 			else
 				vortex_interrupt(dev->irq, dev);
-			local_irq_restore(flags);
+			local_irq_restore_nort(flags);
 		}
 	}
 
Index: linux-3.4/drivers/net/ethernet/freescale/gianfar.c
===================================================================
--- linux-3.4.orig/drivers/net/ethernet/freescale/gianfar.c
+++ linux-3.4/drivers/net/ethernet/freescale/gianfar.c
@@ -1643,7 +1643,7 @@ void stop_gfar(struct net_device *dev)
 
 
 	/* Lock it down */
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	lock_tx_qs(priv);
 	lock_rx_qs(priv);
 
@@ -1651,7 +1651,7 @@ void stop_gfar(struct net_device *dev)
 
 	unlock_rx_qs(priv);
 	unlock_tx_qs(priv);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 
 	/* Free the IRQs */
 	if (priv->device_flags & FSL_GIANFAR_DEV_HAS_MULTI_INTR) {
@@ -2948,7 +2948,7 @@ static void adjust_link(struct net_devic
 	struct phy_device *phydev = priv->phydev;
 	int new_state = 0;
 
-	local_irq_save(flags);
+	local_irq_save_nort(flags);
 	lock_tx_qs(priv);
 
 	if (phydev->link) {
@@ -3015,7 +3015,7 @@ static void adjust_link(struct net_devic
 	if (new_state && netif_msg_link(priv))
 		phy_print_status(phydev);
 	unlock_tx_qs(priv);
-	local_irq_restore(flags);
+	local_irq_restore_nort(flags);
 }
 
 /* Update the hash table based on the current list of multicast
Index: linux-3.4/drivers/usb/host/ohci-hcd.c
===================================================================
--- linux-3.4.orig/drivers/usb/host/ohci-hcd.c
+++ linux-3.4/drivers/usb/host/ohci-hcd.c
@@ -829,9 +829,13 @@ static irqreturn_t ohci_irq (struct usb_
 	}
 
 	if (ints & OHCI_INTR_WDH) {
-		spin_lock (&ohci->lock);
-		dl_done_list (ohci);
-		spin_unlock (&ohci->lock);
+		if (ohci->hcca->done_head == 0) {
+			ints &= ~OHCI_INTR_WDH;
+		} else {
+			spin_lock (&ohci->lock);
+			dl_done_list (ohci);
+			spin_unlock (&ohci->lock);
+		}
 	}
 
 	if (quirk_zfmicro(ohci) && (ints & OHCI_INTR_SF)) {
Index: linux-3.4/include/linux/percpu.h
===================================================================
--- linux-3.4.orig/include/linux/percpu.h
+++ linux-3.4/include/linux/percpu.h
@@ -48,6 +48,31 @@
 	preempt_enable();				\
 } while (0)
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define get_local_var(var)	get_cpu_var(var)
+# define put_local_var(var)	put_cpu_var(var)
+# define get_local_ptr(var)	get_cpu_ptr(var)
+# define put_local_ptr(var)	put_cpu_ptr(var)
+#else
+# define get_local_var(var) (*({			\
+	migrate_disable();				\
+	&__get_cpu_var(var); }))
+
+# define put_local_var(var) do {			\
+	(void)&(var);					\
+	migrate_enable();				\
+} while (0)
+
+# define get_local_ptr(var) ({				\
+	migrate_disable();				\
+	this_cpu_ptr(var); })
+
+# define put_local_ptr(var) do {			\
+	(void)(var);					\
+	migrate_enable();				\
+} while (0)
+#endif
+
 /* minimum unit size, also is the maximum supported allocation size */
 #define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)
 
Index: linux-3.4/include/linux/locallock.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/locallock.h
@@ -0,0 +1,230 @@
+#ifndef _LINUX_LOCALLOCK_H
+#define _LINUX_LOCALLOCK_H
+
+#include <linux/spinlock.h>
+
+#ifdef CONFIG_PREEMPT_RT_BASE
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+# define LL_WARN(cond)	WARN_ON(cond)
+#else
+# define LL_WARN(cond)	do { } while (0)
+#endif
+
+/*
+ * per cpu lock based substitute for local_irq_*()
+ */
+struct local_irq_lock {
+	spinlock_t		lock;
+	struct task_struct	*owner;
+	int			nestcnt;
+	unsigned long		flags;
+};
+
+#define DEFINE_LOCAL_IRQ_LOCK(lvar)					\
+	DEFINE_PER_CPU(struct local_irq_lock, lvar) = {			\
+		.lock = __SPIN_LOCK_UNLOCKED((lvar).lock) }
+
+#define local_irq_lock_init(lvar)					\
+	do {								\
+		int __cpu;						\
+		for_each_possible_cpu(__cpu)				\
+			spin_lock_init(&per_cpu(lvar, __cpu).lock);	\
+	} while (0)
+
+static inline void __local_lock(struct local_irq_lock *lv)
+{
+	if (lv->owner != current) {
+		spin_lock(&lv->lock);
+		LL_WARN(lv->owner);
+		LL_WARN(lv->nestcnt);
+		lv->owner = current;
+	}
+	lv->nestcnt++;
+}
+
+#define local_lock(lvar)					\
+	do { __local_lock(&get_local_var(lvar)); } while (0)
+
+static inline int __local_trylock(struct local_irq_lock *lv)
+{
+	if (lv->owner != current && spin_trylock(&lv->lock)) {
+		LL_WARN(lv->owner);
+		LL_WARN(lv->nestcnt);
+		lv->owner = current;
+		lv->nestcnt = 1;
+		return 1;
+	}
+	return 0;
+}
+
+#define local_trylock(lvar)						\
+	({								\
+		int __locked;						\
+		__locked = __local_trylock(&get_local_var(lvar));	\
+		if (!__locked)						\
+			put_local_var(lvar);				\
+		__locked;						\
+	})
+
+static inline void __local_unlock(struct local_irq_lock *lv)
+{
+	LL_WARN(lv->nestcnt == 0);
+	LL_WARN(lv->owner != current);
+	if (--lv->nestcnt)
+		return;
+
+	lv->owner = NULL;
+	spin_unlock(&lv->lock);
+}
+
+#define local_unlock(lvar)					\
+	do {							\
+		__local_unlock(&__get_cpu_var(lvar));		\
+		put_local_var(lvar);				\
+	} while (0)
+
+static inline void __local_lock_irq(struct local_irq_lock *lv)
+{
+	spin_lock_irqsave(&lv->lock, lv->flags);
+	LL_WARN(lv->owner);
+	LL_WARN(lv->nestcnt);
+	lv->owner = current;
+	lv->nestcnt = 1;
+}
+
+#define local_lock_irq(lvar)						\
+	do { __local_lock_irq(&get_local_var(lvar)); } while (0)
+
+static inline void __local_unlock_irq(struct local_irq_lock *lv)
+{
+	LL_WARN(!lv->nestcnt);
+	LL_WARN(lv->owner != current);
+	lv->owner = NULL;
+	lv->nestcnt = 0;
+	spin_unlock_irq(&lv->lock);
+}
+
+#define local_unlock_irq(lvar)						\
+	do {								\
+		__local_unlock_irq(&__get_cpu_var(lvar));		\
+		put_local_var(lvar);					\
+	} while (0)
+
+static inline int __local_lock_irqsave(struct local_irq_lock *lv)
+{
+	if (lv->owner != current) {
+		__local_lock_irq(lv);
+		return 0;
+	} else {
+		lv->nestcnt++;
+		return 1;
+	}
+}
+
+#define local_lock_irqsave(lvar, _flags)				\
+	do {								\
+		if (__local_lock_irqsave(&get_local_var(lvar)))		\
+			put_local_var(lvar);				\
+		_flags = __get_cpu_var(lvar).flags;			\
+	} while (0)
+
+static inline int __local_unlock_irqrestore(struct local_irq_lock *lv,
+					    unsigned long flags)
+{
+	LL_WARN(!lv->nestcnt);
+	LL_WARN(lv->owner != current);
+	if (--lv->nestcnt)
+		return 0;
+
+	lv->owner = NULL;
+	spin_unlock_irqrestore(&lv->lock, lv->flags);
+	return 1;
+}
+
+#define local_unlock_irqrestore(lvar, flags)				\
+	do {								\
+		if (__local_unlock_irqrestore(&__get_cpu_var(lvar), flags)) \
+			put_local_var(lvar);				\
+	} while (0)
+
+#define local_spin_trylock_irq(lvar, lock)				\
+	({								\
+		int __locked;						\
+		local_lock_irq(lvar);					\
+		__locked = spin_trylock(lock);				\
+		if (!__locked)						\
+			local_unlock_irq(lvar);				\
+		__locked;						\
+	})
+
+#define local_spin_lock_irq(lvar, lock)					\
+	do {								\
+		local_lock_irq(lvar);					\
+		spin_lock(lock);					\
+	} while (0)
+
+#define local_spin_unlock_irq(lvar, lock)				\
+	do {								\
+		spin_unlock(lock);					\
+		local_unlock_irq(lvar);					\
+	} while (0)
+
+#define local_spin_lock_irqsave(lvar, lock, flags)			\
+	do {								\
+		local_lock_irqsave(lvar, flags);			\
+		spin_lock(lock);					\
+	} while (0)
+
+#define local_spin_unlock_irqrestore(lvar, lock, flags)			\
+	do {								\
+		spin_unlock(lock);					\
+		local_unlock_irqrestore(lvar, flags);			\
+	} while (0)
+
+#define get_locked_var(lvar, var)					\
+	(*({								\
+		local_lock(lvar);					\
+		&__get_cpu_var(var);					\
+	}))
+
+#define put_locked_var(lvar, var)		local_unlock(lvar)
+
+#define local_lock_cpu(lvar)						\
+	({								\
+		local_lock(lvar);					\
+		smp_processor_id();					\
+	})
+
+#define local_unlock_cpu(lvar)			local_unlock(lvar)
+
+#else /* PREEMPT_RT_BASE */
+
+#define DEFINE_LOCAL_IRQ_LOCK(lvar)		__typeof__(const int) lvar
+
+static inline void local_irq_lock_init(int lvar) { }
+
+#define local_lock(lvar)			preempt_disable()
+#define local_unlock(lvar)			preempt_enable()
+#define local_lock_irq(lvar)			local_irq_disable()
+#define local_unlock_irq(lvar)			local_irq_enable()
+#define local_lock_irqsave(lvar, flags)		local_irq_save(flags)
+#define local_unlock_irqrestore(lvar, flags)	local_irq_restore(flags)
+
+#define local_spin_trylock_irq(lvar, lock)	spin_trylock_irq(lock)
+#define local_spin_lock_irq(lvar, lock)		spin_lock_irq(lock)
+#define local_spin_unlock_irq(lvar, lock)	spin_unlock_irq(lock)
+#define local_spin_lock_irqsave(lvar, lock, flags)	\
+	spin_lock_irqsave(lock, flags)
+#define local_spin_unlock_irqrestore(lvar, lock, flags)	\
+	spin_unlock_irqrestore(lock, flags)
+
+#define get_locked_var(lvar, var)		get_cpu_var(var)
+#define put_locked_var(lvar, var)		put_cpu_var(var)
+
+#define local_lock_cpu(lvar)			get_cpu()
+#define local_unlock_cpu(lvar)			put_cpu()
+
+#endif
+
+#endif
Index: linux-3.4/include/linux/smp.h
===================================================================
--- linux-3.4.orig/include/linux/smp.h
+++ linux-3.4/include/linux/smp.h
@@ -80,7 +80,6 @@ void __smp_call_function_single(int cpui
 
 int smp_call_function_any(const struct cpumask *mask,
 			  smp_call_func_t func, void *info, int wait);
-
 /*
  * Generic and arch helpers
  */
@@ -219,6 +218,9 @@ smp_call_function_any(const struct cpuma
 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
 #define put_cpu()		preempt_enable()
 
+#define get_cpu_light()		({ migrate_disable(); smp_processor_id(); })
+#define put_cpu_light()		migrate_enable()
+
 /*
  * Callback to arch code if there's nosmp or maxcpus=0 on the
  * boot command line:
Index: linux-3.4/mm/swap.c
===================================================================
--- linux-3.4.orig/mm/swap.c
+++ linux-3.4/mm/swap.c
@@ -30,6 +30,7 @@
 #include <linux/backing-dev.h>
 #include <linux/memcontrol.h>
 #include <linux/gfp.h>
+#include <linux/locallock.h>
 
 #include "internal.h"
 
@@ -40,6 +41,9 @@ static DEFINE_PER_CPU(struct pagevec[NR_
 static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
 static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
 
+static DEFINE_LOCAL_IRQ_LOCK(rotate_lock);
+static DEFINE_LOCAL_IRQ_LOCK(swap_lock);
+
 /*
  * This path almost never happens for VM activity - pages are normally
  * freed via pagevecs.  But it gets used by networking.
@@ -268,11 +272,11 @@ void rotate_reclaimable_page(struct page
 		unsigned long flags;
 
 		page_cache_get(page);
-		local_irq_save(flags);
+		local_lock_irqsave(rotate_lock, flags);
 		pvec = &__get_cpu_var(lru_rotate_pvecs);
 		if (!pagevec_add(pvec, page))
 			pagevec_move_tail(pvec);
-		local_irq_restore(flags);
+		local_unlock_irqrestore(rotate_lock, flags);
 	}
 }
 
@@ -328,12 +332,13 @@ static void activate_page_drain(int cpu)
 void activate_page(struct page *page)
 {
 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
-		struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
+		struct pagevec *pvec = &get_locked_var(swap_lock,
+						       activate_page_pvecs);
 
 		page_cache_get(page);
 		if (!pagevec_add(pvec, page))
 			pagevec_lru_move_fn(pvec, __activate_page, NULL);
-		put_cpu_var(activate_page_pvecs);
+		put_locked_var(swap_lock, activate_page_pvecs);
 	}
 }
 
@@ -373,12 +378,12 @@ EXPORT_SYMBOL(mark_page_accessed);
 
 void __lru_cache_add(struct page *page, enum lru_list lru)
 {
-	struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
+	struct pagevec *pvec = &get_locked_var(swap_lock, lru_add_pvecs)[lru];
 
 	page_cache_get(page);
 	if (!pagevec_add(pvec, page))
 		__pagevec_lru_add(pvec, lru);
-	put_cpu_var(lru_add_pvecs);
+	put_locked_var(swap_lock, lru_add_pvecs);
 }
 EXPORT_SYMBOL(__lru_cache_add);
 
@@ -513,9 +518,9 @@ void lru_add_drain_cpu(int cpu)
 		unsigned long flags;
 
 		/* No harm done if a racing interrupt already did this */
-		local_irq_save(flags);
+		local_lock_irqsave(rotate_lock, flags);
 		pagevec_move_tail(pvec);
-		local_irq_restore(flags);
+		local_unlock_irqrestore(rotate_lock, flags);
 	}
 
 	pvec = &per_cpu(lru_deactivate_pvecs, cpu);
@@ -543,18 +548,19 @@ void deactivate_page(struct page *page)
 		return;
 
 	if (likely(get_page_unless_zero(page))) {
-		struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
+		struct pagevec *pvec = &get_locked_var(swap_lock,
+						       lru_deactivate_pvecs);
 
 		if (!pagevec_add(pvec, page))
 			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
-		put_cpu_var(lru_deactivate_pvecs);
+		put_locked_var(swap_lock, lru_deactivate_pvecs);
 	}
 }
 
 void lru_add_drain(void)
 {
-	lru_add_drain_cpu(get_cpu());
-	put_cpu();
+	lru_add_drain_cpu(local_lock_cpu(swap_lock));
+	local_unlock_cpu(swap_lock);
 }
 
 static void lru_add_drain_per_cpu(struct work_struct *dummy)
@@ -768,6 +774,9 @@ void __init swap_setup(void)
 {
 	unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
 
+	local_irq_lock_init(rotate_lock);
+	local_irq_lock_init(swap_lock);
+
 #ifdef CONFIG_SWAP
 	bdi_init(swapper_space.backing_dev_info);
 #endif
Index: linux-3.4/include/linux/vmstat.h
===================================================================
--- linux-3.4.orig/include/linux/vmstat.h
+++ linux-3.4/include/linux/vmstat.h
@@ -29,7 +29,9 @@ DECLARE_PER_CPU(struct vm_event_state, v
 
 static inline void __count_vm_event(enum vm_event_item item)
 {
+	preempt_disable_rt();
 	__this_cpu_inc(vm_event_states.event[item]);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_event(enum vm_event_item item)
@@ -39,7 +41,9 @@ static inline void count_vm_event(enum v
 
 static inline void __count_vm_events(enum vm_event_item item, long delta)
 {
+	preempt_disable_rt();
 	__this_cpu_add(vm_event_states.event[item], delta);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_events(enum vm_event_item item, long delta)
Index: linux-3.4/mm/vmstat.c
===================================================================
--- linux-3.4.orig/mm/vmstat.c
+++ linux-3.4/mm/vmstat.c
@@ -216,6 +216,7 @@ void __mod_zone_page_state(struct zone *
 	long x;
 	long t;
 
+	preempt_disable_rt();
 	x = delta + __this_cpu_read(*p);
 
 	t = __this_cpu_read(pcp->stat_threshold);
@@ -225,6 +226,7 @@ void __mod_zone_page_state(struct zone *
 		x = 0;
 	}
 	__this_cpu_write(*p, x);
+	preempt_enable_rt();
 }
 EXPORT_SYMBOL(__mod_zone_page_state);
 
@@ -257,6 +259,7 @@ void __inc_zone_state(struct zone *zone,
 	s8 __percpu *p = pcp->vm_stat_diff + item;
 	s8 v, t;
 
+	preempt_disable_rt();
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
@@ -265,6 +268,7 @@ void __inc_zone_state(struct zone *zone,
 		zone_page_state_add(v + overstep, zone, item);
 		__this_cpu_write(*p, -overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
@@ -279,6 +283,7 @@ void __dec_zone_state(struct zone *zone,
 	s8 __percpu *p = pcp->vm_stat_diff + item;
 	s8 v, t;
 
+	preempt_disable_rt();
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
@@ -287,6 +292,7 @@ void __dec_zone_state(struct zone *zone,
 		zone_page_state_add(v - overstep, zone, item);
 		__this_cpu_write(*p, overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
Index: linux-3.4/include/linux/mm.h
===================================================================
--- linux-3.4.orig/include/linux/mm.h
+++ linux-3.4/include/linux/mm.h
@@ -1200,27 +1200,59 @@ static inline pmd_t *pmd_alloc(struct mm
  * overflow into the next struct page (as it might with DEBUG_SPINLOCK).
  * When freeing, reset page->mapping so free_pages_check won't complain.
  */
+#ifndef CONFIG_PREEMPT_RT_FULL
+
 #define __pte_lockptr(page)	&((page)->ptl)
-#define pte_lock_init(_page)	do {					\
-	spin_lock_init(__pte_lockptr(_page));				\
-} while (0)
+
+static inline struct page *pte_lock_init(struct page *page)
+{
+	spin_lock_init(__pte_lockptr(page));
+	return page;
+}
+
 #define pte_lock_deinit(page)	((page)->mapping = NULL)
+
+#else /* !PREEMPT_RT_FULL */
+
+/*
+ * On PREEMPT_RT_FULL the spinlock_t's are too large to embed in the
+ * page frame, hence it only has a pointer and we need to dynamically
+ * allocate the lock when we allocate PTE-pages.
+ *
+ * This is an overall win, since only a small fraction of the pages
+ * will be PTE pages under normal circumstances.
+ */
+
+#define __pte_lockptr(page)	((page)->ptl)
+
+extern struct page *pte_lock_init(struct page *page);
+extern void pte_lock_deinit(struct page *page);
+
+#endif /* PREEMPT_RT_FULL */
+
 #define pte_lockptr(mm, pmd)	({(void)(mm); __pte_lockptr(pmd_page(*(pmd)));})
 #else	/* !USE_SPLIT_PTLOCKS */
 /*
  * We use mm->page_table_lock to guard all pagetable pages of the mm.
  */
-#define pte_lock_init(page)	do {} while (0)
+static inline struct page *pte_lock_init(struct page *page) { return page; }
 #define pte_lock_deinit(page)	do {} while (0)
 #define pte_lockptr(mm, pmd)	({(void)(pmd); &(mm)->page_table_lock;})
 #endif /* USE_SPLIT_PTLOCKS */
 
-static inline void pgtable_page_ctor(struct page *page)
+static inline struct page *__pgtable_page_ctor(struct page *page)
 {
-	pte_lock_init(page);
-	inc_zone_page_state(page, NR_PAGETABLE);
+	page = pte_lock_init(page);
+	if (page)
+		inc_zone_page_state(page, NR_PAGETABLE);
+	return page;
 }
 
+#define pgtable_page_ctor(page)				\
+do {							\
+	page = __pgtable_page_ctor(page);		\
+} while (0)
+
 static inline void pgtable_page_dtor(struct page *page)
 {
 	pte_lock_deinit(page);
Index: linux-3.4/include/linux/mm_types.h
===================================================================
--- linux-3.4.orig/include/linux/mm_types.h
+++ linux-3.4/include/linux/mm_types.h
@@ -12,6 +12,7 @@
 #include <linux/completion.h>
 #include <linux/cpumask.h>
 #include <linux/page-debug-flags.h>
+#include <linux/rcupdate.h>
 #include <asm/page.h>
 #include <asm/mmu.h>
 
@@ -118,7 +119,11 @@ struct page {
 						 * system if PG_buddy is set.
 						 */
 #if USE_SPLIT_PTLOCKS
-		spinlock_t ptl;
+# ifndef CONFIG_PREEMPT_RT_FULL
+	    spinlock_t ptl;
+# else
+	    spinlock_t *ptl;
+# endif
 #endif
 		struct kmem_cache *slab;	/* SLUB: Pointer to slab */
 		struct page *first_page;	/* Compound tail pages */
@@ -388,6 +393,9 @@ struct mm_struct {
 #ifdef CONFIG_CPUMASK_OFFSTACK
 	struct cpumask cpumask_allocation;
 #endif
+#ifdef CONFIG_PREEMPT_RT_BASE
+	struct rcu_head delayed_drop;
+#endif
 };
 
 static inline void mm_init_cpumask(struct mm_struct *mm)
Index: linux-3.4/arch/arm/kernel/process.c
===================================================================
--- linux-3.4.orig/arch/arm/kernel/process.c
+++ linux-3.4/arch/arm/kernel/process.c
@@ -526,6 +526,31 @@ unsigned long arch_randomize_brk(struct 
 }
 
 #ifdef CONFIG_MMU
+
+/*
+ * CONFIG_SPLIT_PTLOCK_CPUS results in a page->ptl lock.  If the lock is not
+ * initialized by pgtable_page_ctor() then a coredump of the vector page will
+ * fail.
+ */
+static int __init vectors_user_mapping_init_page(void)
+{
+	struct page *page;
+	unsigned long addr = 0xffff0000;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pgd = pgd_offset_k(addr);
+	pud = pud_offset(pgd, addr);
+	pmd = pmd_offset(pud, addr);
+	page = pmd_page(*(pmd));
+
+	pgtable_page_ctor(page);
+
+	return 0;
+}
+late_initcall(vectors_user_mapping_init_page);
+
 /*
  * The vectors page is always readable from user space for the
  * atomic helpers and the signal restart code. Insert it into the
Index: linux-3.4/init/Kconfig
===================================================================
--- linux-3.4.orig/init/Kconfig
+++ linux-3.4/init/Kconfig
@@ -1265,6 +1265,7 @@ config SLAB
 
 config SLUB
 	bool "SLUB (Unqueued Allocator)"
+	depends on !PREEMPT_RT_FULL
 	help
 	   SLUB is a slab allocator that minimizes cache line usage
 	   instead of managing queues of cached objects (SLAB approach).
@@ -1276,6 +1277,7 @@ config SLUB
 config SLOB
 	depends on EXPERT
 	bool "SLOB (Simple Allocator)"
+	depends on !PREEMPT_RT_FULL
 	help
 	   SLOB replaces the stock allocator with a drastically simpler
 	   allocator. SLOB is generally more space efficient but
Index: linux-3.4/include/linux/radix-tree.h
===================================================================
--- linux-3.4.orig/include/linux/radix-tree.h
+++ linux-3.4/include/linux/radix-tree.h
@@ -230,7 +230,13 @@ unsigned long radix_tree_next_hole(struc
 				unsigned long index, unsigned long max_scan);
 unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
 				unsigned long index, unsigned long max_scan);
+
+#ifndef CONFIG_PREEMPT_RT_FULL
 int radix_tree_preload(gfp_t gfp_mask);
+#else
+static inline int radix_tree_preload(gfp_t gm) { return 0; }
+#endif
+
 void radix_tree_init(void);
 void *radix_tree_tag_set(struct radix_tree_root *root,
 			unsigned long index, unsigned int tag);
@@ -255,7 +261,7 @@ unsigned long radix_tree_locate_item(str
 
 static inline void radix_tree_preload_end(void)
 {
-	preempt_enable();
+	preempt_enable_nort();
 }
 
 /**
Index: linux-3.4/lib/radix-tree.c
===================================================================
--- linux-3.4.orig/lib/radix-tree.c
+++ linux-3.4/lib/radix-tree.c
@@ -202,12 +202,13 @@ radix_tree_node_alloc(struct radix_tree_
 		 * succeed in getting a node here (and never reach
 		 * kmem_cache_alloc)
 		 */
-		rtp = &__get_cpu_var(radix_tree_preloads);
+		rtp = &get_cpu_var(radix_tree_preloads);
 		if (rtp->nr) {
 			ret = rtp->nodes[rtp->nr - 1];
 			rtp->nodes[rtp->nr - 1] = NULL;
 			rtp->nr--;
 		}
+		put_cpu_var(radix_tree_preloads);
 	}
 	if (ret == NULL)
 		ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
@@ -242,6 +243,7 @@ radix_tree_node_free(struct radix_tree_n
 	call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Load up this CPU's radix_tree_node buffer with sufficient objects to
  * ensure that the addition of a single element in the tree cannot fail.  On
@@ -276,6 +278,7 @@ out:
 	return ret;
 }
 EXPORT_SYMBOL(radix_tree_preload);
+#endif
 
 /*
  *	Return the maximum key which can be store into a
Index: linux-3.4/kernel/panic.c
===================================================================
--- linux-3.4.orig/kernel/panic.c
+++ linux-3.4/kernel/panic.c
@@ -363,9 +363,11 @@ static u64 oops_id;
 
 static int init_oops_id(void)
 {
+#ifndef CONFIG_PREEMPT_RT_FULL
 	if (!oops_id)
 		get_random_bytes(&oops_id, sizeof(oops_id));
 	else
+#endif
 		oops_id++;
 
 	return 0;
Index: linux-3.4/ipc/mqueue.c
===================================================================
--- linux-3.4.orig/ipc/mqueue.c
+++ linux-3.4/ipc/mqueue.c
@@ -813,12 +813,17 @@ static inline void pipelined_send(struct
 				  struct msg_msg *message,
 				  struct ext_wait_queue *receiver)
 {
+	/*
+	 * Keep them in one critical section for PREEMPT_RT:
+	 */
+	preempt_disable_rt();
 	receiver->msg = message;
 	list_del(&receiver->list);
 	receiver->state = STATE_PENDING;
 	wake_up_process(receiver->task);
 	smp_wmb();
 	receiver->state = STATE_READY;
+	preempt_enable_rt();
 }
 
 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
@@ -832,15 +837,19 @@ static inline void pipelined_receive(str
 		wake_up_interruptible(&info->wait_q);
 		return;
 	}
+	/*
+	 * Keep them in one critical section for PREEMPT_RT:
+	 */
+	preempt_disable_rt();
 	msg_insert(sender->msg, info);
 	list_del(&sender->list);
 	sender->state = STATE_PENDING;
 	wake_up_process(sender->task);
 	smp_wmb();
 	sender->state = STATE_READY;
+	preempt_enable_rt();
 }
-
-SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
+ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 		size_t, msg_len, unsigned int, msg_prio,
 		const struct timespec __user *, u_abs_timeout)
 {
Index: linux-3.4/ipc/msg.c
===================================================================
--- linux-3.4.orig/ipc/msg.c
+++ linux-3.4/ipc/msg.c
@@ -259,12 +259,20 @@ static void expunge_all(struct msg_queue
 	while (tmp != &msq->q_receivers) {
 		struct msg_receiver *msr;
 
+		/*
+		 * Make sure that the wakeup doesnt preempt
+		 * this CPU prematurely. (on PREEMPT_RT)
+		 */
+		preempt_disable_rt();
+
 		msr = list_entry(tmp, struct msg_receiver, r_list);
 		tmp = tmp->next;
 		msr->r_msg = NULL;
 		wake_up_process(msr->r_tsk);
 		smp_mb();
 		msr->r_msg = ERR_PTR(res);
+
+		preempt_enable_rt();
 	}
 }
 
@@ -611,6 +619,12 @@ static inline int pipelined_send(struct 
 		    !security_msg_queue_msgrcv(msq, msg, msr->r_tsk,
 					       msr->r_msgtype, msr->r_mode)) {
 
+			/*
+			 * Make sure that the wakeup doesnt preempt
+			 * this CPU prematurely. (on PREEMPT_RT)
+			 */
+			preempt_disable_rt();
+
 			list_del(&msr->r_list);
 			if (msr->r_maxsize < msg->m_ts) {
 				msr->r_msg = NULL;
@@ -624,9 +638,11 @@ static inline int pipelined_send(struct 
 				wake_up_process(msr->r_tsk);
 				smp_mb();
 				msr->r_msg = msg;
+				preempt_enable_rt();
 
 				return 1;
 			}
+			preempt_enable_rt();
 		}
 	}
 	return 0;
Index: linux-3.4/kernel/relay.c
===================================================================
--- linux-3.4.orig/kernel/relay.c
+++ linux-3.4/kernel/relay.c
@@ -340,6 +340,10 @@ static void wakeup_readers(unsigned long
 {
 	struct rchan_buf *buf = (struct rchan_buf *)data;
 	wake_up_interruptible(&buf->read_wait);
+	/*
+	 * Stupid polling for now:
+	 */
+	mod_timer(&buf->timer, jiffies + 1);
 }
 
 /**
@@ -357,6 +361,7 @@ static void __relay_reset(struct rchan_b
 		init_waitqueue_head(&buf->read_wait);
 		kref_init(&buf->kref);
 		setup_timer(&buf->timer, wakeup_readers, (unsigned long)buf);
+		mod_timer(&buf->timer, jiffies + 1);
 	} else
 		del_timer_sync(&buf->timer);
 
@@ -739,15 +744,6 @@ size_t relay_switch_subbuf(struct rchan_
 		else
 			buf->early_bytes += buf->chan->subbuf_size -
 					    buf->padding[old_subbuf];
-		smp_mb();
-		if (waitqueue_active(&buf->read_wait))
-			/*
-			 * Calling wake_up_interruptible() from here
-			 * will deadlock if we happen to be logging
-			 * from the scheduler (trying to re-grab
-			 * rq->lock), so defer it.
-			 */
-			mod_timer(&buf->timer, jiffies + 1);
 	}
 
 	old = buf->data;
Index: linux-3.4/net/ipv4/route.c
===================================================================
--- linux-3.4.orig/net/ipv4/route.c
+++ linux-3.4/net/ipv4/route.c
@@ -250,7 +250,7 @@ struct rt_hash_bucket {
 };
 
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
-	defined(CONFIG_PROVE_LOCKING)
+	defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_PREEMPT_RT_FULL)
 /*
  * Instead of using one spinlock for each rt_hash_bucket, we use a table of spinlocks
  * The size of this table is a power of two and depends on the number of CPUS.
Index: linux-3.4/include/linux/timer.h
===================================================================
--- linux-3.4.orig/include/linux/timer.h
+++ linux-3.4/include/linux/timer.h
@@ -276,7 +276,7 @@ extern void add_timer(struct timer_list 
 
 extern int try_to_del_timer_sync(struct timer_list *timer);
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
   extern int del_timer_sync(struct timer_list *timer);
 #else
 # define del_timer_sync(t)		del_timer(t)
Index: linux-3.4/kernel/timer.c
===================================================================
--- linux-3.4.orig/kernel/timer.c
+++ linux-3.4/kernel/timer.c
@@ -75,6 +75,7 @@ struct tvec_root {
 struct tvec_base {
 	spinlock_t lock;
 	struct timer_list *running_timer;
+	wait_queue_head_t wait_for_running_timer;
 	unsigned long timer_jiffies;
 	unsigned long next_timer;
 	struct tvec_root tv1;
@@ -699,6 +700,36 @@ static struct tvec_base *lock_timer_base
 	}
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
+						  struct tvec_base *old,
+						  struct tvec_base *new)
+{
+	/* See the comment in lock_timer_base() */
+	timer_set_base(timer, NULL);
+	spin_unlock(&old->lock);
+	spin_lock(&new->lock);
+	timer_set_base(timer, new);
+	return new;
+}
+#else
+static inline struct tvec_base *switch_timer_base(struct timer_list *timer,
+						  struct tvec_base *old,
+						  struct tvec_base *new)
+{
+	/*
+	 * We cannot do the above because we might be preempted and
+	 * then the preempter would see NULL and loop forever.
+	 */
+	if (spin_trylock(&new->lock)) {
+		timer_set_base(timer, new);
+		spin_unlock(&old->lock);
+		return new;
+	}
+	return old;
+}
+#endif
+
 static inline int
 __mod_timer(struct timer_list *timer, unsigned long expires,
 						bool pending_only, int pinned)
@@ -725,12 +756,15 @@ __mod_timer(struct timer_list *timer, un
 
 	debug_activate(timer, expires);
 
+	preempt_disable_rt();
 	cpu = smp_processor_id();
 
 #if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
 	if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
 		cpu = get_nohz_timer_target();
 #endif
+	preempt_enable_rt();
+
 	new_base = per_cpu(tvec_bases, cpu);
 
 	if (base != new_base) {
@@ -741,14 +775,8 @@ __mod_timer(struct timer_list *timer, un
 		 * handler yet has not finished. This also guarantees that
 		 * the timer is serialized wrt itself.
 		 */
-		if (likely(base->running_timer != timer)) {
-			/* See the comment in lock_timer_base() */
-			timer_set_base(timer, NULL);
-			spin_unlock(&base->lock);
-			base = new_base;
-			spin_lock(&base->lock);
-			timer_set_base(timer, base);
-		}
+		if (likely(base->running_timer != timer))
+			base = switch_timer_base(timer, base, new_base);
 	}
 
 	timer->expires = expires;
@@ -931,6 +959,29 @@ void add_timer_on(struct timer_list *tim
 }
 EXPORT_SYMBOL_GPL(add_timer_on);
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * Wait for a running timer
+ */
+static void wait_for_running_timer(struct timer_list *timer)
+{
+	struct tvec_base *base = timer->base;
+
+	if (base->running_timer == timer)
+		wait_event(base->wait_for_running_timer,
+			   base->running_timer != timer);
+}
+
+# define wakeup_timer_waiters(b)	wake_up(&(b)->wait_for_tunning_timer)
+#else
+static inline void wait_for_running_timer(struct timer_list *timer)
+{
+	cpu_relax();
+}
+
+# define wakeup_timer_waiters(b)	do { } while (0)
+#endif
+
 /**
  * del_timer - deactive a timer.
  * @timer: the timer to be deactivated
@@ -1003,7 +1054,7 @@ out:
 }
 EXPORT_SYMBOL(try_to_del_timer_sync);
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
 /**
  * del_timer_sync - deactivate a timer and wait for the handler to finish.
  * @timer: the timer to be deactivated
@@ -1063,7 +1114,7 @@ int del_timer_sync(struct timer_list *ti
 		int ret = try_to_del_timer_sync(timer);
 		if (ret >= 0)
 			return ret;
-		cpu_relax();
+		wait_for_running_timer(timer);
 	}
 }
 EXPORT_SYMBOL(del_timer_sync);
@@ -1174,10 +1225,11 @@ static inline void __run_timers(struct t
 
 			spin_unlock_irq(&base->lock);
 			call_timer_fn(timer, fn, data);
+			base->running_timer = NULL;
 			spin_lock_irq(&base->lock);
 		}
 	}
-	base->running_timer = NULL;
+	wake_up(&base->wait_for_running_timer);
 	spin_unlock_irq(&base->lock);
 }
 
@@ -1316,6 +1368,23 @@ unsigned long get_next_timer_interrupt(u
 	 */
 	if (cpu_is_offline(smp_processor_id()))
 		return now + NEXT_TIMER_MAX_DELTA;
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+	/*
+	 * On PREEMPT_RT we cannot sleep here. If the trylock does not
+	 * succeed then we return the worst-case 'expires in 1 tick'
+	 * value. We use the rt functions here directly to avoid a
+	 * migrate_disable() call.
+	 */
+	if (spin_do_trylock(&base->lock)) {
+		if (time_before_eq(base->next_timer, base->timer_jiffies))
+			base->next_timer = __next_timer_interrupt(base);
+		expires = base->next_timer;
+		rt_spin_unlock(&base->lock);
+	} else {
+		expires = now + 1;
+	}
+#else
 	spin_lock(&base->lock);
 	if (time_before_eq(base->next_timer, base->timer_jiffies))
 		base->next_timer = __next_timer_interrupt(base);
@@ -1324,7 +1393,7 @@ unsigned long get_next_timer_interrupt(u
 
 	if (time_before_eq(expires, now))
 		return now;
-
+#endif
 	return cmp_next_hrtimer_event(now, expires);
 }
 #endif
@@ -1340,14 +1409,13 @@ void update_process_times(int user_tick)
 
 	/* Note: this timer irq context must be accounted for as well. */
 	account_process_tick(p, user_tick);
+	scheduler_tick();
 	run_local_timers();
 	rcu_check_callbacks(cpu, user_tick);
-	printk_tick();
-#ifdef CONFIG_IRQ_WORK
+#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL)
 	if (in_irq())
 		irq_work_run();
 #endif
-	scheduler_tick();
 	run_posix_cpu_timers(p);
 }
 
@@ -1358,6 +1426,11 @@ static void run_timer_softirq(struct sof
 {
 	struct tvec_base *base = __this_cpu_read(tvec_bases);
 
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL)
+	irq_work_run();
+#endif
+
+	printk_tick();
 	hrtimer_run_pending();
 
 	if (time_after_eq(jiffies, base->timer_jiffies))
@@ -1684,6 +1757,7 @@ static int __cpuinit init_timers_cpu(int
 	}
 
 	spin_lock_init(&base->lock);
+	init_waitqueue_head(&base->wait_for_running_timer);
 
 	for (j = 0; j < TVN_SIZE; j++) {
 		INIT_LIST_HEAD(base->tv5.vec + j);
@@ -1723,7 +1797,7 @@ static void __cpuinit migrate_timers(int
 
 	BUG_ON(cpu_online(cpu));
 	old_base = per_cpu(tvec_bases, cpu);
-	new_base = get_cpu_var(tvec_bases);
+	new_base = get_local_var(tvec_bases);
 	/*
 	 * The caller is globally serialized and nobody else
 	 * takes two locks at once, deadlock is not possible.
@@ -1744,7 +1818,7 @@ static void __cpuinit migrate_timers(int
 
 	spin_unlock(&old_base->lock);
 	spin_unlock_irq(&new_base->lock);
-	put_cpu_var(tvec_bases);
+	put_local_var(tvec_bases);
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
Index: linux-3.4/include/linux/hrtimer.h
===================================================================
--- linux-3.4.orig/include/linux/hrtimer.h
+++ linux-3.4/include/linux/hrtimer.h
@@ -111,6 +111,8 @@ struct hrtimer {
 	enum hrtimer_restart		(*function)(struct hrtimer *);
 	struct hrtimer_clock_base	*base;
 	unsigned long			state;
+	struct list_head		cb_entry;
+	int				irqsafe;
 #ifdef CONFIG_TIMER_STATS
 	int				start_pid;
 	void				*start_site;
@@ -147,6 +149,7 @@ struct hrtimer_clock_base {
 	int			index;
 	clockid_t		clockid;
 	struct timerqueue_head	active;
+	struct list_head	expired;
 	ktime_t			resolution;
 	ktime_t			(*get_time)(void);
 	ktime_t			softirq_time;
@@ -187,6 +190,9 @@ struct hrtimer_cpu_base {
 	unsigned long			nr_hangs;
 	ktime_t				max_hang_time;
 #endif
+#ifdef CONFIG_PREEMPT_RT_BASE
+	wait_queue_head_t		wait;
+#endif
 	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
 };
 
@@ -374,6 +380,13 @@ static inline int hrtimer_restart(struct
 	return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }
 
+/* Softirq preemption could deadlock timer removal */
+#ifdef CONFIG_PREEMPT_RT_BASE
+  extern void hrtimer_wait_for_timer(const struct hrtimer *timer);
+#else
+# define hrtimer_wait_for_timer(timer)	do { cpu_relax(); } while (0)
+#endif
+
 /* Query timers: */
 extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);
 extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);
Index: linux-3.4/kernel/itimer.c
===================================================================
--- linux-3.4.orig/kernel/itimer.c
+++ linux-3.4/kernel/itimer.c
@@ -213,6 +213,7 @@ again:
 		/* We are sharing ->siglock with it_real_fn() */
 		if (hrtimer_try_to_cancel(timer) < 0) {
 			spin_unlock_irq(&tsk->sighand->siglock);
+			hrtimer_wait_for_timer(&tsk->signal->real_timer);
 			goto again;
 		}
 		expires = timeval_to_ktime(value->it_value);
Index: linux-3.4/kernel/sched/rt.c
===================================================================
--- linux-3.4.orig/kernel/sched/rt.c
+++ linux-3.4/kernel/sched/rt.c
@@ -41,6 +41,7 @@ void init_rt_bandwidth(struct rt_bandwid
 
 	hrtimer_init(&rt_b->rt_period_timer,
 			CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	rt_b->rt_period_timer.irqsafe = 1;
 	rt_b->rt_period_timer.function = sched_rt_period_timer;
 }
 
Index: linux-3.4/fs/timerfd.c
===================================================================
--- linux-3.4.orig/fs/timerfd.c
+++ linux-3.4/fs/timerfd.c
@@ -313,7 +313,7 @@ SYSCALL_DEFINE4(timerfd_settime, int, uf
 		if (hrtimer_try_to_cancel(&ctx->tmr) >= 0)
 			break;
 		spin_unlock_irq(&ctx->wqh.lock);
-		cpu_relax();
+		hrtimer_wait_for_timer(&ctx->tmr);
 	}
 
 	/*
Index: linux-3.4/include/linux/init_task.h
===================================================================
--- linux-3.4.orig/include/linux/init_task.h
+++ linux-3.4/include/linux/init_task.h
@@ -132,6 +132,12 @@ extern struct cred init_cred;
 # define INIT_PERF_EVENTS(tsk)
 #endif
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+# define INIT_TIMER_LIST		.posix_timer_list = NULL,
+#else
+# define INIT_TIMER_LIST
+#endif
+
 #define INIT_TASK_COMM "swapper"
 
 /*
@@ -186,6 +192,7 @@ extern struct cred init_cred;
 	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
 	.pi_lock	= __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock),	\
 	.timer_slack_ns = 50000, /* 50 usec default slack */		\
+	INIT_TIMER_LIST							\
 	.pids = {							\
 		[PIDTYPE_PID]  = INIT_PID_LINK(PIDTYPE_PID),		\
 		[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID),		\
Index: linux-3.4/init/main.c
===================================================================
--- linux-3.4.orig/init/main.c
+++ linux-3.4/init/main.c
@@ -68,6 +68,7 @@
 #include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/perf_event.h>
+#include <linux/posix-timers.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -489,6 +490,7 @@ asmlinkage void __init start_kernel(void
  * Interrupts are still disabled. Do necessary setups, then
  * enable them
  */
+	softirq_early_init();
 	tick_init();
 	boot_cpu_init();
 	page_address_init();
Index: linux-3.4/kernel/posix-cpu-timers.c
===================================================================
--- linux-3.4.orig/kernel/posix-cpu-timers.c
+++ linux-3.4/kernel/posix-cpu-timers.c
@@ -682,7 +682,7 @@ static int posix_cpu_timer_set(struct k_
 	/*
 	 * Disarm any old timer after extracting its expiry time.
 	 */
-	BUG_ON(!irqs_disabled());
+	BUG_ON_NONRT(!irqs_disabled());
 
 	ret = 0;
 	old_incr = timer->it.cpu.incr;
@@ -1198,7 +1198,7 @@ void posix_cpu_timer_schedule(struct k_i
 	/*
 	 * Now re-arm for the new expiry time.
 	 */
-	BUG_ON(!irqs_disabled());
+	BUG_ON_NONRT(!irqs_disabled());
 	arm_timer(timer);
 	spin_unlock(&p->sighand->siglock);
 
@@ -1262,10 +1262,11 @@ static inline int fastpath_timer_check(s
 	sig = tsk->signal;
 	if (sig->cputimer.running) {
 		struct task_cputime group_sample;
+		unsigned long flags;
 
-		raw_spin_lock(&sig->cputimer.lock);
+		raw_spin_lock_irqsave(&sig->cputimer.lock, flags);
 		group_sample = sig->cputimer.cputime;
-		raw_spin_unlock(&sig->cputimer.lock);
+		raw_spin_unlock_irqrestore(&sig->cputimer.lock, flags);
 
 		if (task_cputime_expired(&group_sample, &sig->cputime_expires))
 			return 1;
@@ -1279,13 +1280,13 @@ static inline int fastpath_timer_check(s
  * already updated our counts.  We need to check if any timers fire now.
  * Interrupts are disabled.
  */
-void run_posix_cpu_timers(struct task_struct *tsk)
+static void __run_posix_cpu_timers(struct task_struct *tsk)
 {
 	LIST_HEAD(firing);
 	struct k_itimer *timer, *next;
 	unsigned long flags;
 
-	BUG_ON(!irqs_disabled());
+	BUG_ON_NONRT(!irqs_disabled());
 
 	/*
 	 * The fast path checks that there are no expired thread or thread
@@ -1343,6 +1344,190 @@ void run_posix_cpu_timers(struct task_st
 	}
 }
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+#include <linux/kthread.h>
+#include <linux/cpu.h>
+DEFINE_PER_CPU(struct task_struct *, posix_timer_task);
+DEFINE_PER_CPU(struct task_struct *, posix_timer_tasklist);
+
+static int posix_cpu_timers_thread(void *data)
+{
+	int cpu = (long)data;
+
+	BUG_ON(per_cpu(posix_timer_task,cpu) != current);
+
+	while (!kthread_should_stop()) {
+		struct task_struct *tsk = NULL;
+		struct task_struct *next = NULL;
+
+		if (cpu_is_offline(cpu))
+			goto wait_to_die;
+
+		/* grab task list */
+		raw_local_irq_disable();
+		tsk = per_cpu(posix_timer_tasklist, cpu);
+		per_cpu(posix_timer_tasklist, cpu) = NULL;
+		raw_local_irq_enable();
+
+		/* its possible the list is empty, just return */
+		if (!tsk) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			schedule();
+			__set_current_state(TASK_RUNNING);
+			continue;
+		}
+
+		/* Process task list */
+		while (1) {
+			/* save next */
+			next = tsk->posix_timer_list;
+
+			/* run the task timers, clear its ptr and
+			 * unreference it
+			 */
+			__run_posix_cpu_timers(tsk);
+			tsk->posix_timer_list = NULL;
+			put_task_struct(tsk);
+
+			/* check if this is the last on the list */
+			if (next == tsk)
+				break;
+			tsk = next;
+		}
+	}
+	return 0;
+
+wait_to_die:
+	/* Wait for kthread_stop */
+	set_current_state(TASK_INTERRUPTIBLE);
+	while (!kthread_should_stop()) {
+		schedule();
+		set_current_state(TASK_INTERRUPTIBLE);
+	}
+	__set_current_state(TASK_RUNNING);
+	return 0;
+}
+
+static inline int __fastpath_timer_check(struct task_struct *tsk)
+{
+	/* tsk == current, ensure it is safe to use ->signal/sighand */
+	if (unlikely(tsk->exit_state))
+		return 0;
+
+	if (!task_cputime_zero(&tsk->cputime_expires))
+			return 1;
+
+	if (!task_cputime_zero(&tsk->signal->cputime_expires))
+			return 1;
+
+	return 0;
+}
+
+void run_posix_cpu_timers(struct task_struct *tsk)
+{
+	unsigned long cpu = smp_processor_id();
+	struct task_struct *tasklist;
+
+	BUG_ON(!irqs_disabled());
+	if(!per_cpu(posix_timer_task, cpu))
+		return;
+	/* get per-cpu references */
+	tasklist = per_cpu(posix_timer_tasklist, cpu);
+
+	/* check to see if we're already queued */
+	if (!tsk->posix_timer_list && __fastpath_timer_check(tsk)) {
+		get_task_struct(tsk);
+		if (tasklist) {
+			tsk->posix_timer_list = tasklist;
+		} else {
+			/*
+			 * The list is terminated by a self-pointing
+			 * task_struct
+			 */
+			tsk->posix_timer_list = tsk;
+		}
+		per_cpu(posix_timer_tasklist, cpu) = tsk;
+
+		wake_up_process(per_cpu(posix_timer_task, cpu));
+	}
+}
+
+/*
+ * posix_cpu_thread_call - callback that gets triggered when a CPU is added.
+ * Here we can start up the necessary migration thread for the new CPU.
+ */
+static int posix_cpu_thread_call(struct notifier_block *nfb,
+				 unsigned long action, void *hcpu)
+{
+	int cpu = (long)hcpu;
+	struct task_struct *p;
+	struct sched_param param;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		p = kthread_create(posix_cpu_timers_thread, hcpu,
+					"posixcputmr/%d",cpu);
+		if (IS_ERR(p))
+			return NOTIFY_BAD;
+		p->flags |= PF_NOFREEZE;
+		kthread_bind(p, cpu);
+		/* Must be high prio to avoid getting starved */
+		param.sched_priority = MAX_RT_PRIO-1;
+		sched_setscheduler(p, SCHED_FIFO, &param);
+		per_cpu(posix_timer_task,cpu) = p;
+		break;
+	case CPU_ONLINE:
+		/* Strictly unneccessary, as first user will wake it. */
+		wake_up_process(per_cpu(posix_timer_task,cpu));
+		break;
+#ifdef CONFIG_HOTPLUG_CPU
+	case CPU_UP_CANCELED:
+		/* Unbind it from offline cpu so it can run.  Fall thru. */
+		kthread_bind(per_cpu(posix_timer_task, cpu),
+			     cpumask_any(cpu_online_mask));
+		kthread_stop(per_cpu(posix_timer_task,cpu));
+		per_cpu(posix_timer_task,cpu) = NULL;
+		break;
+	case CPU_DEAD:
+		kthread_stop(per_cpu(posix_timer_task,cpu));
+		per_cpu(posix_timer_task,cpu) = NULL;
+		break;
+#endif
+	}
+	return NOTIFY_OK;
+}
+
+/* Register at highest priority so that task migration (migrate_all_tasks)
+ * happens before everything else.
+ */
+static struct notifier_block __devinitdata posix_cpu_thread_notifier = {
+	.notifier_call = posix_cpu_thread_call,
+	.priority = 10
+};
+
+static int __init posix_cpu_thread_init(void)
+{
+	void *hcpu = (void *)(long)smp_processor_id();
+	/* Start one for boot CPU. */
+	unsigned long cpu;
+
+	/* init the per-cpu posix_timer_tasklets */
+	for_each_possible_cpu(cpu)
+		per_cpu(posix_timer_tasklist, cpu) = NULL;
+
+	posix_cpu_thread_call(&posix_cpu_thread_notifier, CPU_UP_PREPARE, hcpu);
+	posix_cpu_thread_call(&posix_cpu_thread_notifier, CPU_ONLINE, hcpu);
+	register_cpu_notifier(&posix_cpu_thread_notifier);
+	return 0;
+}
+early_initcall(posix_cpu_thread_init);
+#else /* CONFIG_PREEMPT_RT_BASE */
+void run_posix_cpu_timers(struct task_struct *tsk)
+{
+	__run_posix_cpu_timers(tsk);
+}
+#endif /* CONFIG_PREEMPT_RT_BASE */
+
 /*
  * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
  * The tsk->sighand->siglock must be held by the caller.
Index: linux-3.4/include/linux/rcupdate.h
===================================================================
--- linux-3.4.orig/include/linux/rcupdate.h
+++ linux-3.4/include/linux/rcupdate.h
@@ -101,6 +101,9 @@ extern void call_rcu(struct rcu_head *he
 
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define call_rcu_bh	call_rcu
+#else
 /**
  * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
  * @head: structure to be used for queueing the RCU updates.
@@ -121,6 +124,7 @@ extern void call_rcu(struct rcu_head *he
  */
 extern void call_rcu_bh(struct rcu_head *head,
 			void (*func)(struct rcu_head *head));
+#endif
 
 /**
  * call_rcu_sched() - Queue an RCU for invocation after sched grace period.
@@ -156,6 +160,11 @@ void synchronize_rcu(void);
  * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
  */
 #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
+#ifndef CONFIG_PREEMPT_RT_FULL
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+#else
+static inline int sched_rcu_preempt_depth(void) { return 0; }
+#endif
 
 #else /* #ifdef CONFIG_PREEMPT_RCU */
 
@@ -179,6 +188,8 @@ static inline int rcu_preempt_depth(void
 	return 0;
 }
 
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
 /* Internal to kernel */
@@ -324,7 +335,14 @@ static inline int rcu_read_lock_held(voi
  * rcu_read_lock_bh_held() is defined out of line to avoid #include-file
  * hell.
  */
+#ifdef CONFIG_PREEMPT_RT_FULL
+static inline int rcu_read_lock_bh_held(void)
+{
+	return rcu_read_lock_held();
+}
+#else
 extern int rcu_read_lock_bh_held(void);
+#endif
 
 /**
  * rcu_read_lock_sched_held() - might we be in RCU-sched read-side critical section?
@@ -773,10 +791,14 @@ static inline void rcu_read_unlock(void)
 static inline void rcu_read_lock_bh(void)
 {
 	local_bh_disable();
+#ifdef CONFIG_PREEMPT_RT_FULL
+	rcu_read_lock();
+#else
 	__acquire(RCU_BH);
 	rcu_lock_acquire(&rcu_bh_lock_map);
 	rcu_lockdep_assert(!rcu_is_cpu_idle(),
 			   "rcu_read_lock_bh() used illegally while idle");
+#endif
 }
 
 /*
@@ -786,10 +808,14 @@ static inline void rcu_read_lock_bh(void
  */
 static inline void rcu_read_unlock_bh(void)
 {
+#ifdef CONFIG_PREEMPT_RT_FULL
+	rcu_read_unlock();
+#else
 	rcu_lockdep_assert(!rcu_is_cpu_idle(),
 			   "rcu_read_unlock_bh() used illegally while idle");
 	rcu_lock_release(&rcu_bh_lock_map);
 	__release(RCU_BH);
+#endif
 	local_bh_enable();
 }
 
Index: linux-3.4/kernel/sched/features.h
===================================================================
--- linux-3.4.orig/kernel/sched/features.h
+++ linux-3.4/kernel/sched/features.h
@@ -60,11 +60,15 @@ SCHED_FEAT(OWNER_SPIN, true)
  */
 SCHED_FEAT(NONTASK_POWER, true)
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Queue remote wakeups on the target CPU and process them
  * using the scheduler IPI. Reduces rq->lock contention/bounces.
  */
 SCHED_FEAT(TTWU_QUEUE, true)
+#else
+SCHED_FEAT(TTWU_QUEUE, false)
+#endif
 
 SCHED_FEAT(FORCE_SD_OVERLAP, false)
 SCHED_FEAT(RT_RUNTIME_SHARE, true)
Index: linux-3.4/kernel/stop_machine.c
===================================================================
--- linux-3.4.orig/kernel/stop_machine.c
+++ linux-3.4/kernel/stop_machine.c
@@ -29,12 +29,12 @@ struct cpu_stop_done {
 	atomic_t		nr_todo;	/* nr left to execute */
 	bool			executed;	/* actually executed? */
 	int			ret;		/* collected return value */
-	struct completion	completion;	/* fired if nr_todo reaches 0 */
+	struct task_struct	*waiter;	/* woken when nr_todo reaches 0 */
 };
 
 /* the actual stopper, one per every possible cpu, enabled on online cpus */
 struct cpu_stopper {
-	spinlock_t		lock;
+	raw_spinlock_t		lock;
 	bool			enabled;	/* is this stopper enabled? */
 	struct list_head	works;		/* list of pending works */
 	struct task_struct	*thread;	/* stopper thread */
@@ -47,7 +47,7 @@ static void cpu_stop_init_done(struct cp
 {
 	memset(done, 0, sizeof(*done));
 	atomic_set(&done->nr_todo, nr_todo);
-	init_completion(&done->completion);
+	done->waiter = current;
 }
 
 /* signal completion unless @done is NULL */
@@ -56,8 +56,10 @@ static void cpu_stop_signal_done(struct 
 	if (done) {
 		if (executed)
 			done->executed = true;
-		if (atomic_dec_and_test(&done->nr_todo))
-			complete(&done->completion);
+		if (atomic_dec_and_test(&done->nr_todo)) {
+			wake_up_process(done->waiter);
+			done->waiter = NULL;
+		}
 	}
 }
 
@@ -67,7 +69,7 @@ static void cpu_stop_queue_work(struct c
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&stopper->lock, flags);
+	raw_spin_lock_irqsave(&stopper->lock, flags);
 
 	if (stopper->enabled) {
 		list_add_tail(&work->list, &stopper->works);
@@ -75,7 +77,23 @@ static void cpu_stop_queue_work(struct c
 	} else
 		cpu_stop_signal_done(work->done, false);
 
-	spin_unlock_irqrestore(&stopper->lock, flags);
+	raw_spin_unlock_irqrestore(&stopper->lock, flags);
+}
+
+static void wait_for_stop_done(struct cpu_stop_done *done)
+{
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	while (atomic_read(&done->nr_todo)) {
+		schedule();
+		set_current_state(TASK_UNINTERRUPTIBLE);
+	}
+	/*
+	 * We need to wait until cpu_stop_signal_done() has cleared
+	 * done->waiter.
+	 */
+	while (done->waiter)
+		cpu_relax();
+	set_current_state(TASK_RUNNING);
 }
 
 /**
@@ -109,7 +127,7 @@ int stop_one_cpu(unsigned int cpu, cpu_s
 
 	cpu_stop_init_done(&done, 1);
 	cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu), &work);
-	wait_for_completion(&done.completion);
+	wait_for_stop_done(&done);
 	return done.executed ? done.ret : -ENOENT;
 }
 
@@ -135,6 +153,7 @@ void stop_one_cpu_nowait(unsigned int cp
 
 /* static data for stop_cpus */
 static DEFINE_MUTEX(stop_cpus_mutex);
+static DEFINE_MUTEX(stopper_lock);
 static DEFINE_PER_CPU(struct cpu_stop_work, stop_cpus_work);
 
 static void queue_stop_cpus_work(const struct cpumask *cpumask,
@@ -153,15 +172,14 @@ static void queue_stop_cpus_work(const s
 	}
 
 	/*
-	 * Disable preemption while queueing to avoid getting
-	 * preempted by a stopper which might wait for other stoppers
-	 * to enter @fn which can lead to deadlock.
+	 * Make sure that all work is queued on all cpus before we
+	 * any of the cpus can execute it.
 	 */
-	preempt_disable();
+	mutex_lock(&stopper_lock);
 	for_each_cpu(cpu, cpumask)
 		cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu),
 				    &per_cpu(stop_cpus_work, cpu));
-	preempt_enable();
+	mutex_unlock(&stopper_lock);
 }
 
 static int __stop_cpus(const struct cpumask *cpumask,
@@ -171,7 +189,7 @@ static int __stop_cpus(const struct cpum
 
 	cpu_stop_init_done(&done, cpumask_weight(cpumask));
 	queue_stop_cpus_work(cpumask, fn, arg, &done);
-	wait_for_completion(&done.completion);
+	wait_for_stop_done(&done);
 	return done.executed ? done.ret : -ENOENT;
 }
 
@@ -259,13 +277,13 @@ repeat:
 	}
 
 	work = NULL;
-	spin_lock_irq(&stopper->lock);
+	raw_spin_lock_irq(&stopper->lock);
 	if (!list_empty(&stopper->works)) {
 		work = list_first_entry(&stopper->works,
 					struct cpu_stop_work, list);
 		list_del_init(&work->list);
 	}
-	spin_unlock_irq(&stopper->lock);
+	raw_spin_unlock_irq(&stopper->lock);
 
 	if (work) {
 		cpu_stop_fn_t fn = work->fn;
@@ -275,6 +293,16 @@ repeat:
 
 		__set_current_state(TASK_RUNNING);
 
+		/*
+		 * Wait until the stopper finished scheduling on all
+		 * cpus
+		 */
+		mutex_lock(&stopper_lock);
+		/*
+		 * Let other cpu threads continue as well
+		 */
+		mutex_unlock(&stopper_lock);
+
 		/* cpu stop callbacks are not allowed to sleep */
 		preempt_disable();
 
@@ -289,7 +317,13 @@ repeat:
 			  kallsyms_lookup((unsigned long)fn, NULL, NULL, NULL,
 					  ksym_buf), arg);
 
+		/*
+		 * Make sure that the wakeup and setting done->waiter
+		 * to NULL is atomic.
+		 */
+		local_irq_disable();
 		cpu_stop_signal_done(done, true);
+		local_irq_enable();
 	} else
 		schedule();
 
@@ -317,6 +351,7 @@ static int __cpuinit cpu_stop_cpu_callba
 		if (IS_ERR(p))
 			return notifier_from_errno(PTR_ERR(p));
 		get_task_struct(p);
+		p->flags |= PF_STOMPER;
 		kthread_bind(p, cpu);
 		sched_set_stop_task(cpu, p);
 		stopper->thread = p;
@@ -326,9 +361,9 @@ static int __cpuinit cpu_stop_cpu_callba
 		/* strictly unnecessary, as first user will wake it */
 		wake_up_process(stopper->thread);
 		/* mark enabled */
-		spin_lock_irq(&stopper->lock);
+		raw_spin_lock_irq(&stopper->lock);
 		stopper->enabled = true;
-		spin_unlock_irq(&stopper->lock);
+		raw_spin_unlock_irq(&stopper->lock);
 		break;
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -341,11 +376,11 @@ static int __cpuinit cpu_stop_cpu_callba
 		/* kill the stopper */
 		kthread_stop(stopper->thread);
 		/* drain remaining works */
-		spin_lock_irq(&stopper->lock);
+		raw_spin_lock_irq(&stopper->lock);
 		list_for_each_entry(work, &stopper->works, list)
 			cpu_stop_signal_done(work->done, false);
 		stopper->enabled = false;
-		spin_unlock_irq(&stopper->lock);
+		raw_spin_unlock_irq(&stopper->lock);
 		/* release the stopper */
 		put_task_struct(stopper->thread);
 		stopper->thread = NULL;
@@ -376,7 +411,7 @@ static int __init cpu_stop_init(void)
 	for_each_possible_cpu(cpu) {
 		struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
 
-		spin_lock_init(&stopper->lock);
+		raw_spin_lock_init(&stopper->lock);
 		INIT_LIST_HEAD(&stopper->works);
 	}
 
@@ -570,7 +605,7 @@ int stop_machine_from_inactive_cpu(int (
 	ret = stop_machine_cpu_stop(&smdata);
 
 	/* Busy wait for completion. */
-	while (!completion_done(&done.completion))
+	while (atomic_read(&done.nr_todo))
 		cpu_relax();
 
 	mutex_unlock(&stop_cpus_mutex);
Index: linux-3.4/include/linux/cpu.h
===================================================================
--- linux-3.4.orig/include/linux/cpu.h
+++ linux-3.4/include/linux/cpu.h
@@ -75,8 +75,10 @@ enum {
 	/* migration should happen before other stuff but after perf */
 	CPU_PRI_PERF		= 20,
 	CPU_PRI_MIGRATION	= 10,
-	/* prepare workqueues for other notifiers */
-	CPU_PRI_WORKQUEUE	= 5,
+
+	CPU_PRI_WORKQUEUE_ACTIVE	= 5,  /* prepare workqueues for others */
+	CPU_PRI_NORMAL			= 0,
+	CPU_PRI_WORKQUEUE_INACTIVE	= -5, /* flush workqueues after others */
 };
 
 #define CPU_ONLINE		0x0002 /* CPU (unsigned)v is up */
@@ -176,6 +178,8 @@ extern struct bus_type cpu_subsys;
 
 extern void get_online_cpus(void);
 extern void put_online_cpus(void);
+extern void pin_current_cpu(void);
+extern void unpin_current_cpu(void);
 #define hotcpu_notifier(fn, pri)	cpu_notifier(fn, pri)
 #define register_hotcpu_notifier(nb)	register_cpu_notifier(nb)
 #define unregister_hotcpu_notifier(nb)	unregister_cpu_notifier(nb)
@@ -198,6 +202,8 @@ static inline void cpu_hotplug_driver_un
 
 #define get_online_cpus()	do { } while (0)
 #define put_online_cpus()	do { } while (0)
+static inline void pin_current_cpu(void) { }
+static inline void unpin_current_cpu(void) { }
 #define hotcpu_notifier(fn, pri)	do { (void)(fn); } while (0)
 /* These aren't inline functions due to a GCC bug. */
 #define register_hotcpu_notifier(nb)	({ (void)(nb); 0; })
Index: linux-3.4/kernel/cpu.c
===================================================================
--- linux-3.4.orig/kernel/cpu.c
+++ linux-3.4/kernel/cpu.c
@@ -46,7 +46,12 @@ static int cpu_hotplug_disabled;
 
 static struct {
 	struct task_struct *active_writer;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	/* Makes the lock keep the task's state */
+	spinlock_t lock;
+#else
 	struct mutex lock; /* Synchronizes accesses to refcount, */
+#endif
 	/*
 	 * Also blocks the new readers during
 	 * an ongoing cpu hotplug operation.
@@ -54,18 +59,128 @@ static struct {
 	int refcount;
 } cpu_hotplug = {
 	.active_writer = NULL,
+#ifdef CONFIG_PREEMPT_RT_FULL
+	.lock = __SPIN_LOCK_UNLOCKED(cpu_hotplug.lock),
+#else
 	.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
+#endif
 	.refcount = 0,
 };
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define hotplug_lock() rt_spin_lock(&cpu_hotplug.lock)
+# define hotplug_unlock() rt_spin_unlock(&cpu_hotplug.lock)
+#else
+# define hotplug_lock() mutex_lock(&cpu_hotplug.lock)
+# define hotplug_unlock() mutex_unlock(&cpu_hotplug.lock)
+#endif
+
+struct hotplug_pcp {
+	struct task_struct *unplug;
+	int refcount;
+	struct completion synced;
+};
+
+static DEFINE_PER_CPU(struct hotplug_pcp, hotplug_pcp);
+
+/**
+ * pin_current_cpu - Prevent the current cpu from being unplugged
+ *
+ * Lightweight version of get_online_cpus() to prevent cpu from being
+ * unplugged when code runs in a migration disabled region.
+ *
+ * Must be called with preemption disabled (preempt_count = 1)!
+ */
+void pin_current_cpu(void)
+{
+	struct hotplug_pcp *hp;
+
+retry:
+	hp = &__get_cpu_var(hotplug_pcp);
+
+	if (!hp->unplug || hp->refcount || preempt_count() > 1 ||
+	    hp->unplug == current || (current->flags & PF_STOMPER)) {
+		hp->refcount++;
+		return;
+	}
+	preempt_enable();
+	hotplug_lock();
+	hotplug_unlock();
+	preempt_disable();
+	goto retry;
+}
+
+/**
+ * unpin_current_cpu - Allow unplug of current cpu
+ *
+ * Must be called with preemption or interrupts disabled!
+ */
+void unpin_current_cpu(void)
+{
+	struct hotplug_pcp *hp = &__get_cpu_var(hotplug_pcp);
+
+	WARN_ON(hp->refcount <= 0);
+
+	/* This is safe. sync_unplug_thread is pinned to this cpu */
+	if (!--hp->refcount && hp->unplug && hp->unplug != current &&
+	    !(current->flags & PF_STOMPER))
+		wake_up_process(hp->unplug);
+}
+
+/*
+ * FIXME: Is this really correct under all circumstances ?
+ */
+static int sync_unplug_thread(void *data)
+{
+	struct hotplug_pcp *hp = data;
+
+	preempt_disable();
+	hp->unplug = current;
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	while (hp->refcount) {
+		schedule_preempt_disabled();
+		set_current_state(TASK_UNINTERRUPTIBLE);
+	}
+	set_current_state(TASK_RUNNING);
+	preempt_enable();
+	complete(&hp->synced);
+	return 0;
+}
+
+/*
+ * Start the sync_unplug_thread on the target cpu and wait for it to
+ * complete.
+ */
+static int cpu_unplug_begin(unsigned int cpu)
+{
+	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
+	struct task_struct *tsk;
+
+	init_completion(&hp->synced);
+	tsk = kthread_create(sync_unplug_thread, hp, "sync_unplug/%d", cpu);
+	if (IS_ERR(tsk))
+		return (PTR_ERR(tsk));
+	kthread_bind(tsk, cpu);
+	wake_up_process(tsk);
+	wait_for_completion(&hp->synced);
+	return 0;
+}
+
+static void cpu_unplug_done(unsigned int cpu)
+{
+	struct hotplug_pcp *hp = &per_cpu(hotplug_pcp, cpu);
+
+	hp->unplug = NULL;
+}
+
 void get_online_cpus(void)
 {
 	might_sleep();
 	if (cpu_hotplug.active_writer == current)
 		return;
-	mutex_lock(&cpu_hotplug.lock);
+	hotplug_lock();
 	cpu_hotplug.refcount++;
-	mutex_unlock(&cpu_hotplug.lock);
+	hotplug_unlock();
 
 }
 EXPORT_SYMBOL_GPL(get_online_cpus);
@@ -74,10 +189,10 @@ void put_online_cpus(void)
 {
 	if (cpu_hotplug.active_writer == current)
 		return;
-	mutex_lock(&cpu_hotplug.lock);
+	hotplug_lock();
 	if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
 		wake_up_process(cpu_hotplug.active_writer);
-	mutex_unlock(&cpu_hotplug.lock);
+	hotplug_unlock();
 
 }
 EXPORT_SYMBOL_GPL(put_online_cpus);
@@ -109,11 +224,11 @@ static void cpu_hotplug_begin(void)
 	cpu_hotplug.active_writer = current;
 
 	for (;;) {
-		mutex_lock(&cpu_hotplug.lock);
+		hotplug_lock();
 		if (likely(!cpu_hotplug.refcount))
 			break;
 		__set_current_state(TASK_UNINTERRUPTIBLE);
-		mutex_unlock(&cpu_hotplug.lock);
+		hotplug_unlock();
 		schedule();
 	}
 }
@@ -121,7 +236,7 @@ static void cpu_hotplug_begin(void)
 static void cpu_hotplug_done(void)
 {
 	cpu_hotplug.active_writer = NULL;
-	mutex_unlock(&cpu_hotplug.lock);
+	hotplug_unlock();
 }
 
 #else /* #if CONFIG_HOTPLUG_CPU */
@@ -210,13 +325,14 @@ static int __ref take_cpu_down(void *_pa
 /* Requires cpu_add_remove_lock to be held */
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
-	int err, nr_calls = 0;
+	int mycpu, err, nr_calls = 0;
 	void *hcpu = (void *)(long)cpu;
 	unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
 	struct take_cpu_down_param tcd_param = {
 		.mod = mod,
 		.hcpu = hcpu,
 	};
+	cpumask_var_t cpumask;
 
 	if (num_online_cpus() == 1)
 		return -EBUSY;
@@ -224,7 +340,26 @@ static int __ref _cpu_down(unsigned int 
 	if (!cpu_online(cpu))
 		return -EINVAL;
 
+	/* Move the downtaker off the unplug cpu */
+	if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
+		return -ENOMEM;
+	cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
+	set_cpus_allowed_ptr(current, cpumask);
+	free_cpumask_var(cpumask);
+	migrate_disable();
+	mycpu = smp_processor_id();
+	if (mycpu == cpu) {
+		printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
+		migrate_enable();
+		return -EBUSY;
+	}
+
 	cpu_hotplug_begin();
+	err = cpu_unplug_begin(cpu);
+	if (err) {
+		printk("cpu_unplug_begin(%d) failed\n", cpu);
+		goto out_cancel;
+	}
 
 	err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
 	if (err) {
@@ -263,6 +398,9 @@ static int __ref _cpu_down(unsigned int 
 	check_for_tasks(cpu);
 
 out_release:
+	cpu_unplug_done(cpu);
+out_cancel:
+	migrate_enable();
 	cpu_hotplug_done();
 	if (!err)
 		cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
Index: linux-3.4/lib/smp_processor_id.c
===================================================================
--- linux-3.4.orig/lib/smp_processor_id.c
+++ linux-3.4/lib/smp_processor_id.c
@@ -39,9 +39,9 @@ notrace unsigned int debug_smp_processor
 	if (!printk_ratelimit())
 		goto out_enable;
 
-	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "
-			"code: %s/%d\n",
-			preempt_count() - 1, current->comm, current->pid);
+	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x %08x] "
+	       "code: %s/%d\n", preempt_count() - 1,
+	       __migrate_disabled(current), current->comm, current->pid);
 	print_symbol("caller is %s\n", (long)__builtin_return_address(0));
 	dump_stack();
 
Index: linux-3.4/include/linux/ftrace_event.h
===================================================================
--- linux-3.4.orig/include/linux/ftrace_event.h
+++ linux-3.4/include/linux/ftrace_event.h
@@ -49,7 +49,8 @@ struct trace_entry {
 	unsigned char		flags;
 	unsigned char		preempt_count;
 	int			pid;
-	int			padding;
+	unsigned short		migrate_disable;
+	unsigned short		padding;
 };
 
 #define FTRACE_MAX_EVENT						\
Index: linux-3.4/kernel/trace/trace.c
===================================================================
--- linux-3.4.orig/kernel/trace/trace.c
+++ linux-3.4/kernel/trace/trace.c
@@ -414,11 +414,13 @@ EXPORT_SYMBOL_GPL(tracing_is_on);
  */
 void trace_wake_up(void)
 {
+#ifndef CONFIG_PREEMPT_RT_FULL
 	const unsigned long delay = msecs_to_jiffies(2);
 
 	if (trace_flags & TRACE_ITER_BLOCK)
 		return;
 	schedule_delayed_work(&wakeup_work, delay);
+#endif
 }
 
 static int __init set_buf_size(char *str)
@@ -775,6 +777,12 @@ update_max_tr_single(struct trace_array 
 }
 #endif /* CONFIG_TRACER_MAX_TRACE */
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+static void default_wait_pipe(struct trace_iterator *iter);
+#else
+#define default_wait_pipe	poll_wait_pipe
+#endif
+
 /**
  * register_tracer - register a tracer with the ftrace system.
  * @type - the plugin for the tracer
@@ -1179,6 +1187,8 @@ tracing_generic_entry_update(struct trac
 		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
 		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
 		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
+
+	entry->migrate_disable	= (tsk) ? __migrate_disabled(tsk) & 0xFF : 0;
 }
 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
 
@@ -1937,9 +1947,10 @@ static void print_lat_help_header(struct
 	seq_puts(m, "#                | / _----=> need-resched    \n");
 	seq_puts(m, "#                || / _---=> hardirq/softirq \n");
 	seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
-	seq_puts(m, "#                |||| /     delay             \n");
-	seq_puts(m, "#  cmd     pid   ||||| time  |   caller      \n");
-	seq_puts(m, "#     \\   /      |||||  \\    |   /           \n");
+	seq_puts(m, "#                |||| / _--=> migrate-disable\n");
+	seq_puts(m, "#                ||||| /     delay           \n");
+	seq_puts(m, "#  cmd     pid   |||||| time  |   caller     \n");
+	seq_puts(m, "#     \\   /      |||||  \\   |   /          \n");
 }
 
 static void print_event_info(struct trace_array *tr, struct seq_file *m)
@@ -3300,6 +3311,7 @@ static int tracing_release_pipe(struct i
 	return 0;
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 static unsigned int
 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
 {
@@ -3321,8 +3333,7 @@ tracing_poll_pipe(struct file *filp, pol
 	}
 }
 
-
-void default_wait_pipe(struct trace_iterator *iter)
+static void default_wait_pipe(struct trace_iterator *iter)
 {
 	DEFINE_WAIT(wait);
 
@@ -3333,6 +3344,20 @@ void default_wait_pipe(struct trace_iter
 
 	finish_wait(&trace_wait, &wait);
 }
+#else
+static unsigned int
+tracing_poll_pipe(struct file *filp, poll_table *poll_table)
+{
+	struct trace_iterator *iter = filp->private_data;
+
+	if ((trace_flags & TRACE_ITER_BLOCK) || !trace_empty(iter))
+		return POLLIN | POLLRDNORM;
+	poll_wait_pipe(iter);
+	if (!trace_empty(iter))
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+#endif
 
 /*
  * This is a make-shift waitqueue.
Index: linux-3.4/kernel/trace/trace_events.c
===================================================================
--- linux-3.4.orig/kernel/trace/trace_events.c
+++ linux-3.4/kernel/trace/trace_events.c
@@ -116,7 +116,8 @@ static int trace_define_common_fields(vo
 	__common_field(unsigned char, flags);
 	__common_field(unsigned char, preempt_count);
 	__common_field(int, pid);
-	__common_field(int, padding);
+	__common_field(unsigned short, migrate_disable);
+	__common_field(unsigned short, padding);
 
 	return ret;
 }
Index: linux-3.4/kernel/trace/trace_output.c
===================================================================
--- linux-3.4.orig/kernel/trace/trace_output.c
+++ linux-3.4/kernel/trace/trace_output.c
@@ -593,6 +593,11 @@ int trace_print_lat_fmt(struct trace_seq
 	else
 		ret = trace_seq_putc(s, '.');
 
+	if (entry->migrate_disable)
+		ret = trace_seq_printf(s, "%x", entry->migrate_disable);
+	else
+		ret = trace_seq_putc(s, '.');
+
 	return ret;
 }
 
Index: linux-3.4/kernel/sched/debug.c
===================================================================
--- linux-3.4.orig/kernel/sched/debug.c
+++ linux-3.4/kernel/sched/debug.c
@@ -237,6 +237,9 @@ void print_rt_rq(struct seq_file *m, int
 	P(rt_throttled);
 	PN(rt_time);
 	PN(rt_runtime);
+#ifdef CONFIG_SMP
+	P(rt_nr_migratory);
+#endif
 
 #undef PN
 #undef P
@@ -485,6 +488,10 @@ void proc_sched_show_task(struct task_st
 	P(se.load.weight);
 	P(policy);
 	P(prio);
+#ifdef CONFIG_PREEMPT_RT_FULL
+	P(migrate_disable);
+#endif
+	P(rt.nr_cpus_allowed);
 #undef PN
 #undef __PN
 #undef P
Index: linux-3.4/kernel/trace/trace.h
===================================================================
--- linux-3.4.orig/kernel/trace/trace.h
+++ linux-3.4/kernel/trace/trace.h
@@ -354,7 +354,6 @@ void trace_init_global_iter(struct trace
 
 void tracing_iter_reset(struct trace_iterator *iter, int cpu);
 
-void default_wait_pipe(struct trace_iterator *iter);
 void poll_wait_pipe(struct trace_iterator *iter);
 
 void ftrace(struct trace_array *tr,
Index: linux-3.4/kernel/trace/ring_buffer.c
===================================================================
--- linux-3.4.orig/kernel/trace/ring_buffer.c
+++ linux-3.4/kernel/trace/ring_buffer.c
@@ -446,7 +446,7 @@ struct ring_buffer_per_cpu {
 	int				cpu;
 	atomic_t			record_disabled;
 	struct ring_buffer		*buffer;
-	raw_spinlock_t			reader_lock;	/* serialize readers */
+	spinlock_t			reader_lock;	/* serialize readers */
 	arch_spinlock_t			lock;
 	struct lock_class_key		lock_key;
 	struct list_head		*pages;
@@ -1017,6 +1017,44 @@ static int rb_allocate_pages(struct ring
 	return -ENOMEM;
 }
 
+static inline int ok_to_lock(void)
+{
+	if (in_nmi())
+		return 0;
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (in_atomic() || irqs_disabled())
+		return 0;
+#endif
+	return 1;
+}
+
+static int
+read_buffer_lock(struct ring_buffer_per_cpu *cpu_buffer,
+		 unsigned long *flags)
+{
+	/*
+	 * If an NMI die dumps out the content of the ring buffer
+	 * do not grab locks. We also permanently disable the ring
+	 * buffer too. A one time deal is all you get from reading
+	 * the ring buffer from an NMI.
+	 */
+	if (!ok_to_lock()) {
+		if (spin_trylock_irqsave(&cpu_buffer->reader_lock, *flags))
+			return 1;
+		tracing_off_permanent();
+		return 0;
+	}
+	spin_lock_irqsave(&cpu_buffer->reader_lock, *flags);
+	return 1;
+}
+
+static void
+read_buffer_unlock(struct ring_buffer_per_cpu *cpu_buffer,
+		   unsigned long flags, int locked)
+{
+	if (locked)
+		spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
 static struct ring_buffer_per_cpu *
 rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
 {
@@ -1032,7 +1070,7 @@ rb_allocate_cpu_buffer(struct ring_buffe
 
 	cpu_buffer->cpu = cpu;
 	cpu_buffer->buffer = buffer;
-	raw_spin_lock_init(&cpu_buffer->reader_lock);
+	spin_lock_init(&cpu_buffer->reader_lock);
 	lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
 	cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 
@@ -1227,9 +1265,11 @@ rb_remove_pages(struct ring_buffer_per_c
 {
 	struct buffer_page *bpage;
 	struct list_head *p;
+	unsigned long flags;
 	unsigned i;
+	int locked;
 
-	raw_spin_lock_irq(&cpu_buffer->reader_lock);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	rb_head_page_deactivate(cpu_buffer);
 
 	for (i = 0; i < nr_pages; i++) {
@@ -1247,7 +1287,7 @@ rb_remove_pages(struct ring_buffer_per_c
 	rb_check_pages(cpu_buffer);
 
 out:
-	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 }
 
 static void
@@ -1256,9 +1296,11 @@ rb_insert_pages(struct ring_buffer_per_c
 {
 	struct buffer_page *bpage;
 	struct list_head *p;
+	unsigned long flags;
 	unsigned i;
+	int locked;
 
-	raw_spin_lock_irq(&cpu_buffer->reader_lock);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	rb_head_page_deactivate(cpu_buffer);
 
 	for (i = 0; i < nr_pages; i++) {
@@ -1273,7 +1315,7 @@ rb_insert_pages(struct ring_buffer_per_c
 	rb_check_pages(cpu_buffer);
 
 out:
-	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 }
 
 /**
@@ -2714,7 +2756,7 @@ unsigned long ring_buffer_oldest_event_t
 		return 0;
 
 	cpu_buffer = buffer->buffers[cpu];
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 	/*
 	 * if the tail is on reader_page, oldest time stamp is on the reader
 	 * page
@@ -2724,7 +2766,7 @@ unsigned long ring_buffer_oldest_event_t
 	else
 		bpage = rb_set_head_page(cpu_buffer);
 	ret = bpage->page->time_stamp;
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
 	return ret;
 }
@@ -2888,15 +2930,16 @@ void ring_buffer_iter_reset(struct ring_
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	unsigned long flags;
+	int locked;
 
 	if (!iter)
 		return;
 
 	cpu_buffer = iter->cpu_buffer;
 
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	rb_iter_reset(iter);
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
 
@@ -3314,21 +3357,6 @@ rb_iter_peek(struct ring_buffer_iter *it
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
 
-static inline int rb_ok_to_lock(void)
-{
-	/*
-	 * If an NMI die dumps out the content of the ring buffer
-	 * do not grab locks. We also permanently disable the ring
-	 * buffer too. A one time deal is all you get from reading
-	 * the ring buffer from an NMI.
-	 */
-	if (likely(!in_nmi()))
-		return 1;
-
-	tracing_off_permanent();
-	return 0;
-}
-
 /**
  * ring_buffer_peek - peek at the next event to be read
  * @buffer: The ring buffer to read
@@ -3346,22 +3374,17 @@ ring_buffer_peek(struct ring_buffer *buf
 	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
 	struct ring_buffer_event *event;
 	unsigned long flags;
-	int dolock;
+	int locked;
 
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
 		return NULL;
 
-	dolock = rb_ok_to_lock();
  again:
-	local_irq_save(flags);
-	if (dolock)
-		raw_spin_lock(&cpu_buffer->reader_lock);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
 		rb_advance_reader(cpu_buffer);
-	if (dolock)
-		raw_spin_unlock(&cpu_buffer->reader_lock);
-	local_irq_restore(flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
 		goto again;
@@ -3383,11 +3406,12 @@ ring_buffer_iter_peek(struct ring_buffer
 	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
 	struct ring_buffer_event *event;
 	unsigned long flags;
+	int locked;
 
  again:
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	event = rb_iter_peek(iter, ts);
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
 		goto again;
@@ -3413,9 +3437,7 @@ ring_buffer_consume(struct ring_buffer *
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct ring_buffer_event *event = NULL;
 	unsigned long flags;
-	int dolock;
-
-	dolock = rb_ok_to_lock();
+	int locked;
 
  again:
 	/* might be called in atomic */
@@ -3425,9 +3447,7 @@ ring_buffer_consume(struct ring_buffer *
 		goto out;
 
 	cpu_buffer = buffer->buffers[cpu];
-	local_irq_save(flags);
-	if (dolock)
-		raw_spin_lock(&cpu_buffer->reader_lock);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 
 	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
 	if (event) {
@@ -3435,9 +3455,8 @@ ring_buffer_consume(struct ring_buffer *
 		rb_advance_reader(cpu_buffer);
 	}
 
-	if (dolock)
-		raw_spin_unlock(&cpu_buffer->reader_lock);
-	local_irq_restore(flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
+
 
  out:
 	preempt_enable();
@@ -3522,17 +3541,18 @@ ring_buffer_read_start(struct ring_buffe
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	unsigned long flags;
+	int locked;
 
 	if (!iter)
 		return;
 
 	cpu_buffer = iter->cpu_buffer;
 
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	arch_spin_lock(&cpu_buffer->lock);
 	rb_iter_reset(iter);
 	arch_spin_unlock(&cpu_buffer->lock);
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_start);
 
@@ -3566,8 +3586,9 @@ ring_buffer_read(struct ring_buffer_iter
 	struct ring_buffer_event *event;
 	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
 	unsigned long flags;
+	int locked;
 
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
  again:
 	event = rb_iter_peek(iter, ts);
 	if (!event)
@@ -3578,7 +3599,7 @@ ring_buffer_read(struct ring_buffer_iter
 
 	rb_advance_iter(iter);
  out:
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
 	return event;
 }
@@ -3643,13 +3664,14 @@ void ring_buffer_reset_cpu(struct ring_b
 {
 	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
 	unsigned long flags;
+	int locked;
 
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
 		return;
 
 	atomic_inc(&cpu_buffer->record_disabled);
 
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 
 	if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
 		goto out;
@@ -3661,7 +3683,7 @@ void ring_buffer_reset_cpu(struct ring_b
 	arch_spin_unlock(&cpu_buffer->lock);
 
  out:
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
 	atomic_dec(&cpu_buffer->record_disabled);
 }
@@ -3688,22 +3710,16 @@ int ring_buffer_empty(struct ring_buffer
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	unsigned long flags;
-	int dolock;
+	int locked;
 	int cpu;
 	int ret;
 
-	dolock = rb_ok_to_lock();
-
 	/* yes this is racy, but if you don't like the race, lock the buffer */
 	for_each_buffer_cpu(buffer, cpu) {
 		cpu_buffer = buffer->buffers[cpu];
-		local_irq_save(flags);
-		if (dolock)
-			raw_spin_lock(&cpu_buffer->reader_lock);
+		locked = read_buffer_lock(cpu_buffer, &flags);
 		ret = rb_per_cpu_empty(cpu_buffer);
-		if (dolock)
-			raw_spin_unlock(&cpu_buffer->reader_lock);
-		local_irq_restore(flags);
+		read_buffer_unlock(cpu_buffer, flags, locked);
 
 		if (!ret)
 			return 0;
@@ -3722,22 +3738,16 @@ int ring_buffer_empty_cpu(struct ring_bu
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	unsigned long flags;
-	int dolock;
+	int locked;
 	int ret;
 
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
 		return 1;
 
-	dolock = rb_ok_to_lock();
-
 	cpu_buffer = buffer->buffers[cpu];
-	local_irq_save(flags);
-	if (dolock)
-		raw_spin_lock(&cpu_buffer->reader_lock);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 	ret = rb_per_cpu_empty(cpu_buffer);
-	if (dolock)
-		raw_spin_unlock(&cpu_buffer->reader_lock);
-	local_irq_restore(flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
 	return ret;
 }
@@ -3912,6 +3922,7 @@ int ring_buffer_read_page(struct ring_bu
 	unsigned int commit;
 	unsigned int read;
 	u64 save_timestamp;
+	int locked;
 	int ret = -1;
 
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
@@ -3933,7 +3944,7 @@ int ring_buffer_read_page(struct ring_bu
 	if (!bpage)
 		goto out;
 
-	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	locked = read_buffer_lock(cpu_buffer, &flags);
 
 	reader = rb_get_reader_page(cpu_buffer);
 	if (!reader)
@@ -4057,7 +4068,7 @@ int ring_buffer_read_page(struct ring_bu
 		memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
 
  out_unlock:
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	read_buffer_unlock(cpu_buffer, flags, locked);
 
  out:
 	return ret;
Index: linux-3.4/kernel/lockdep.c
===================================================================
--- linux-3.4.orig/kernel/lockdep.c
+++ linux-3.4/kernel/lockdep.c
@@ -3495,6 +3495,7 @@ static void check_flags(unsigned long fl
 		}
 	}
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 	/*
 	 * We dont accurately track softirq state in e.g.
 	 * hardirq contexts (such as on 4KSTACKS), so only
@@ -3509,6 +3510,7 @@ static void check_flags(unsigned long fl
 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
 		}
 	}
+#endif
 
 	if (!debug_locks)
 		print_irqtrace_events(current);
Index: linux-3.4/kernel/Kconfig.locks
===================================================================
--- linux-3.4.orig/kernel/Kconfig.locks
+++ linux-3.4/kernel/Kconfig.locks
@@ -199,4 +199,4 @@ config INLINE_WRITE_UNLOCK_IRQRESTORE
 	def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
 
 config MUTEX_SPIN_ON_OWNER
-	def_bool SMP && !DEBUG_MUTEXES
+	def_bool SMP && !DEBUG_MUTEXES && !PREEMPT_RT_FULL
Index: linux-3.4/include/linux/hardirq.h
===================================================================
--- linux-3.4.orig/include/linux/hardirq.h
+++ linux-3.4/include/linux/hardirq.h
@@ -60,7 +60,11 @@
 #define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)
 #define NMI_OFFSET	(1UL << NMI_SHIFT)
 
-#define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)
+#else
+# define SOFTIRQ_DISABLE_OFFSET (0)
+#endif
 
 #ifndef PREEMPT_ACTIVE
 #define PREEMPT_ACTIVE_BITS	1
@@ -73,10 +77,17 @@
 #endif
 
 #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
-#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
 #define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
 				 | NMI_MASK))
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+# define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
+# define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
+#else
+# define softirq_count()	(0UL)
+extern int in_serving_softirq(void);
+#endif
+
 /*
  * Are we doing bottom half or hardware interrupt processing?
  * Are we in a softirq context? Interrupt context?
@@ -86,7 +97,6 @@
 #define in_irq()		(hardirq_count())
 #define in_softirq()		(softirq_count())
 #define in_interrupt()		(irq_count())
-#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
 
 /*
  * Are we in NMI context?
Index: linux-3.4/arch/powerpc/kernel/irq.c
===================================================================
--- linux-3.4.orig/arch/powerpc/kernel/irq.c
+++ linux-3.4/arch/powerpc/kernel/irq.c
@@ -523,6 +523,7 @@ void irq_ctx_init(void)
 	}
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 static inline void do_softirq_onstack(void)
 {
 	struct thread_info *curtp, *irqtp;
@@ -559,6 +560,7 @@ void do_softirq(void)
 
 	local_irq_restore(flags);
 }
+#endif
 
 irq_hw_number_t virq_to_hw(unsigned int virq)
 {
Index: linux-3.4/arch/powerpc/kernel/misc_32.S
===================================================================
--- linux-3.4.orig/arch/powerpc/kernel/misc_32.S
+++ linux-3.4/arch/powerpc/kernel/misc_32.S
@@ -36,6 +36,7 @@
 
 	.text
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	stw	r0,4(r1)
@@ -46,6 +47,7 @@ _GLOBAL(call_do_softirq)
 	lwz	r0,4(r1)
 	mtlr	r0
 	blr
+#endif
 
 _GLOBAL(call_handle_irq)
 	mflr	r0
Index: linux-3.4/arch/powerpc/kernel/misc_64.S
===================================================================
--- linux-3.4.orig/arch/powerpc/kernel/misc_64.S
+++ linux-3.4/arch/powerpc/kernel/misc_64.S
@@ -29,6 +29,7 @@
 
 	.text
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	std	r0,16(r1)
@@ -39,6 +40,7 @@ _GLOBAL(call_do_softirq)
 	ld	r0,16(r1)
 	mtlr	r0
 	blr
+#endif
 
 _GLOBAL(call_handle_irq)
 	ld	r8,0(r6)
Index: linux-3.4/arch/sh/kernel/irq.c
===================================================================
--- linux-3.4.orig/arch/sh/kernel/irq.c
+++ linux-3.4/arch/sh/kernel/irq.c
@@ -149,6 +149,7 @@ void irq_ctx_exit(int cpu)
 	hardirq_ctx[cpu] = NULL;
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 asmlinkage void do_softirq(void)
 {
 	unsigned long flags;
@@ -191,6 +192,7 @@ asmlinkage void do_softirq(void)
 
 	local_irq_restore(flags);
 }
+#endif
 #else
 static inline void handle_one_irq(unsigned int irq)
 {
Index: linux-3.4/arch/sparc/kernel/irq_64.c
===================================================================
--- linux-3.4.orig/arch/sparc/kernel/irq_64.c
+++ linux-3.4/arch/sparc/kernel/irq_64.c
@@ -698,6 +698,7 @@ void __irq_entry handler_irq(int pil, st
 	set_irq_regs(old_regs);
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 void do_softirq(void)
 {
 	unsigned long flags;
@@ -723,6 +724,7 @@ void do_softirq(void)
 
 	local_irq_restore(flags);
 }
+#endif
 
 #ifdef CONFIG_HOTPLUG_CPU
 void fixup_irqs(void)
Index: linux-3.4/arch/x86/kernel/entry_64.S
===================================================================
--- linux-3.4.orig/arch/x86/kernel/entry_64.S
+++ linux-3.4/arch/x86/kernel/entry_64.S
@@ -1240,6 +1240,7 @@ ENTRY(kernel_execve)
 	CFI_ENDPROC
 END(kernel_execve)
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /* Call softirq on interrupt stack. Interrupts are off. */
 ENTRY(call_softirq)
 	CFI_STARTPROC
@@ -1259,6 +1260,7 @@ ENTRY(call_softirq)
 	ret
 	CFI_ENDPROC
 END(call_softirq)
+#endif
 
 #ifdef CONFIG_XEN
 zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
Index: linux-3.4/arch/x86/kernel/irq_32.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/irq_32.c
+++ linux-3.4/arch/x86/kernel/irq_32.c
@@ -149,6 +149,7 @@ void __cpuinit irq_ctx_init(int cpu)
 	       cpu, per_cpu(hardirq_ctx, cpu),  per_cpu(softirq_ctx, cpu));
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 asmlinkage void do_softirq(void)
 {
 	unsigned long flags;
@@ -179,6 +180,7 @@ asmlinkage void do_softirq(void)
 
 	local_irq_restore(flags);
 }
+#endif
 
 bool handle_irq(unsigned irq, struct pt_regs *regs)
 {
Index: linux-3.4/arch/x86/kernel/irq_64.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/irq_64.c
+++ linux-3.4/arch/x86/kernel/irq_64.c
@@ -88,7 +88,7 @@ bool handle_irq(unsigned irq, struct pt_
 	return true;
 }
 
-
+#ifndef CONFIG_PREEMPT_RT_FULL
 extern void call_softirq(void);
 
 asmlinkage void do_softirq(void)
@@ -108,3 +108,4 @@ asmlinkage void do_softirq(void)
 	}
 	local_irq_restore(flags);
 }
+#endif
Index: linux-3.4/include/linux/irq.h
===================================================================
--- linux-3.4.orig/include/linux/irq.h
+++ linux-3.4/include/linux/irq.h
@@ -73,6 +73,7 @@ typedef	void (*irq_preflow_handler_t)(st
  * IRQ_MOVE_PCNTXT		- Interrupt can be migrated from process context
  * IRQ_NESTED_TRHEAD		- Interrupt nests into another thread
  * IRQ_PER_CPU_DEVID		- Dev_id is a per-cpu variable
+ * IRQ_NO_SOFTIRQ_CALL		- No softirq processing in the irq thread context (RT)
  */
 enum {
 	IRQ_TYPE_NONE		= 0x00000000,
@@ -97,12 +98,14 @@ enum {
 	IRQ_NESTED_THREAD	= (1 << 15),
 	IRQ_NOTHREAD		= (1 << 16),
 	IRQ_PER_CPU_DEVID	= (1 << 17),
+	IRQ_NO_SOFTIRQ_CALL	= (1 << 18),
 };
 
 #define IRQF_MODIFY_MASK	\
 	(IRQ_TYPE_SENSE_MASK | IRQ_NOPROBE | IRQ_NOREQUEST | \
 	 IRQ_NOAUTOEN | IRQ_MOVE_PCNTXT | IRQ_LEVEL | IRQ_NO_BALANCING | \
-	 IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID)
+	 IRQ_PER_CPU | IRQ_NESTED_THREAD | IRQ_NOTHREAD | IRQ_PER_CPU_DEVID | \
+	 IRQ_NO_SOFTIRQ_CALL)
 
 #define IRQ_NO_BALANCING_MASK	(IRQ_PER_CPU | IRQ_NO_BALANCING)
 
Index: linux-3.4/kernel/irq/settings.h
===================================================================
--- linux-3.4.orig/kernel/irq/settings.h
+++ linux-3.4/kernel/irq/settings.h
@@ -14,6 +14,7 @@ enum {
 	_IRQ_NO_BALANCING	= IRQ_NO_BALANCING,
 	_IRQ_NESTED_THREAD	= IRQ_NESTED_THREAD,
 	_IRQ_PER_CPU_DEVID	= IRQ_PER_CPU_DEVID,
+	_IRQ_NO_SOFTIRQ_CALL	= IRQ_NO_SOFTIRQ_CALL,
 	_IRQF_MODIFY_MASK	= IRQF_MODIFY_MASK,
 };
 
@@ -26,6 +27,7 @@ enum {
 #define IRQ_NOAUTOEN		GOT_YOU_MORON
 #define IRQ_NESTED_THREAD	GOT_YOU_MORON
 #define IRQ_PER_CPU_DEVID	GOT_YOU_MORON
+#define IRQ_NO_SOFTIRQ_CALL	GOT_YOU_MORON
 #undef IRQF_MODIFY_MASK
 #define IRQF_MODIFY_MASK	GOT_YOU_MORON
 
@@ -36,6 +38,16 @@ irq_settings_clr_and_set(struct irq_desc
 	desc->status_use_accessors |= (set & _IRQF_MODIFY_MASK);
 }
 
+static inline bool irq_settings_no_softirq_call(struct irq_desc *desc)
+{
+	return desc->status_use_accessors & _IRQ_NO_SOFTIRQ_CALL;
+}
+
+static inline void irq_settings_set_no_softirq_call(struct irq_desc *desc)
+{
+	desc->status_use_accessors |= _IRQ_NO_SOFTIRQ_CALL;
+}
+
 static inline bool irq_settings_is_per_cpu(struct irq_desc *desc)
 {
 	return desc->status_use_accessors & _IRQ_PER_CPU;
Index: linux-3.4/drivers/md/raid5.c
===================================================================
--- linux-3.4.orig/drivers/md/raid5.c
+++ linux-3.4/drivers/md/raid5.c
@@ -1309,8 +1309,9 @@ static void __raid_run_ops(struct stripe
 	struct raid5_percpu *percpu;
 	unsigned long cpu;
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	percpu = per_cpu_ptr(conf->percpu, cpu);
+	spin_lock(&percpu->lock);
 	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
 		ops_run_biofill(sh);
 		overlap_clear++;
@@ -1362,7 +1363,8 @@ static void __raid_run_ops(struct stripe
 			if (test_and_clear_bit(R5_Overlap, &dev->flags))
 				wake_up(&sh->raid_conf->wait_for_overlap);
 		}
-	put_cpu();
+	spin_unlock(&percpu->lock);
+	put_cpu_light();
 }
 
 #ifdef CONFIG_MULTICORE_RAID456
@@ -4758,6 +4760,7 @@ static int raid5_alloc_percpu(struct r5c
 			break;
 		}
 		per_cpu_ptr(conf->percpu, cpu)->scribble = scribble;
+		spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
 	}
 #ifdef CONFIG_HOTPLUG_CPU
 	conf->cpu_notify.notifier_call = raid456_cpu_notify;
Index: linux-3.4/drivers/md/raid5.h
===================================================================
--- linux-3.4.orig/drivers/md/raid5.h
+++ linux-3.4/drivers/md/raid5.h
@@ -417,6 +417,7 @@ struct r5conf {
 	int			recovery_disabled;
 	/* per cpu variables */
 	struct raid5_percpu {
+		spinlock_t	lock;	     /* Protection for -RT */
 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
 		void		*scribble;   /* space for constructing buffer
 					      * lists and performing address
Index: linux-3.4/include/linux/rtmutex.h
===================================================================
--- linux-3.4.orig/include/linux/rtmutex.h
+++ linux-3.4/include/linux/rtmutex.h
@@ -14,7 +14,7 @@
 
 #include <linux/linkage.h>
 #include <linux/plist.h>
-#include <linux/spinlock_types.h>
+#include <linux/spinlock_types_raw.h>
 
 extern int max_lock_depth; /* for sysctl */
 
@@ -29,9 +29,10 @@ struct rt_mutex {
 	raw_spinlock_t		wait_lock;
 	struct plist_head	wait_list;
 	struct task_struct	*owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
 	int			save_state;
-	const char 		*name, *file;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+	const char		*file;
+	const char		*name;
 	int			line;
 	void			*magic;
 #endif
@@ -56,19 +57,39 @@ struct hrtimer_sleeper;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
 	, .name = #mutexname, .file = __FILE__, .line = __LINE__
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, __func__)
+
+# define rt_mutex_init(mutex)					\
+	do {							\
+		raw_spin_lock_init(&(mutex)->wait_lock);	\
+		__rt_mutex_init(mutex, #mutex);			\
+	} while (0)
+
  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
 #else
 # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL)
+
+# define rt_mutex_init(mutex)					\
+	do {							\
+		raw_spin_lock_init(&(mutex)->wait_lock);	\
+		__rt_mutex_init(mutex, #mutex);			\
+	} while (0)
+
 # define rt_mutex_debug_task_free(t)			do { } while (0)
 #endif
 
-#define __RT_MUTEX_INITIALIZER(mutexname) \
-	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
 	, .wait_list = PLIST_HEAD_INIT(mutexname.wait_list) \
 	, .owner = NULL \
-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname)}
+	__DEBUG_RT_MUTEX_INITIALIZER(mutexname)
+
+
+#define __RT_MUTEX_INITIALIZER(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname) }
+
+#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname)    \
+	  , .save_state = 1 }
 
 #define DEFINE_RT_MUTEX(mutexname) \
 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
@@ -90,6 +111,7 @@ extern void rt_mutex_destroy(struct rt_m
 extern void rt_mutex_lock(struct rt_mutex *lock);
 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
 						int detect_deadlock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock, int detect_deadlock);
 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
 					struct hrtimer_sleeper *timeout,
 					int detect_deadlock);
Index: linux-3.4/kernel/rtmutex.c
===================================================================
--- linux-3.4.orig/kernel/rtmutex.c
+++ linux-3.4/kernel/rtmutex.c
@@ -8,6 +8,12 @@
  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
  *  Copyright (C) 2006 Esben Nielsen
  *
+ * Adaptive Spinlocks:
+ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
+ *                                   and Peter Morreale,
+ * Adaptive Spinlocks simplification:
+ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
+ *
  *  See Documentation/rt-mutex-design.txt for details.
  */
 #include <linux/spinlock.h>
@@ -67,6 +73,12 @@ static void fixup_rt_mutex_waiters(struc
 		clear_rt_mutex_waiters(lock);
 }
 
+static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
+{
+	return waiter && waiter != PI_WAKEUP_INPROGRESS &&
+		waiter != PI_REQUEUE_INPROGRESS;
+}
+
 /*
  * We can speed up the acquire/release, if the architecture
  * supports cmpxchg and if there's no debugging state to be set up
@@ -90,6 +102,12 @@ static inline void mark_rt_mutex_waiters
 }
 #endif
 
+static inline void init_lists(struct rt_mutex *lock)
+{
+	if (unlikely(!lock->wait_list.node_list.prev))
+		plist_head_init(&lock->wait_list);
+}
+
 /*
  * Calculate task priority from the waiter list priority
  *
@@ -136,6 +154,14 @@ static void rt_mutex_adjust_prio(struct 
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 }
 
+static void rt_mutex_wake_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (waiter->savestate)
+		wake_up_lock_sleeper(waiter->task);
+	else
+		wake_up_process(waiter->task);
+}
+
 /*
  * Max number of times we'll walk the boosting chain:
  */
@@ -196,7 +222,7 @@ static int rt_mutex_adjust_prio_chain(st
 	 * reached or the state of the chain has changed while we
 	 * dropped the locks.
 	 */
-	if (!waiter)
+	if (!rt_mutex_real_waiter(waiter))
 		goto out_unlock_pi;
 
 	/*
@@ -247,13 +273,15 @@ static int rt_mutex_adjust_prio_chain(st
 	/* Release the task */
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 	if (!rt_mutex_owner(lock)) {
+		struct rt_mutex_waiter *lock_top_waiter;
+
 		/*
 		 * If the requeue above changed the top waiter, then we need
 		 * to wake the new top waiter up to try to get the lock.
 		 */
-
-		if (top_waiter != rt_mutex_top_waiter(lock))
-			wake_up_process(rt_mutex_top_waiter(lock)->task);
+		lock_top_waiter = rt_mutex_top_waiter(lock);
+		if (top_waiter != lock_top_waiter)
+			rt_mutex_wake_waiter(lock_top_waiter);
 		raw_spin_unlock(&lock->wait_lock);
 		goto out_put_task;
 	}
@@ -298,6 +326,25 @@ static int rt_mutex_adjust_prio_chain(st
 	return ret;
 }
 
+
+#define STEAL_NORMAL  0
+#define STEAL_LATERAL 1
+
+/*
+ * Note that RT tasks are excluded from lateral-steals to prevent the
+ * introduction of an unbounded latency
+ */
+static inline int lock_is_stealable(struct task_struct *task,
+				    struct task_struct *pendowner, int mode)
+{
+    if (mode == STEAL_NORMAL || rt_task(task)) {
+	    if (task->prio >= pendowner->prio)
+		    return 0;
+    } else if (task->prio > pendowner->prio)
+	    return 0;
+    return 1;
+}
+
 /*
  * Try to take an rt-mutex
  *
@@ -307,8 +354,9 @@ static int rt_mutex_adjust_prio_chain(st
  * @task:   the task which wants to acquire the lock
  * @waiter: the waiter that is queued to the lock's wait list. (could be NULL)
  */
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
-		struct rt_mutex_waiter *waiter)
+static int
+__try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+		       struct rt_mutex_waiter *waiter, int mode)
 {
 	/*
 	 * We have to be careful here if the atomic speedups are
@@ -341,12 +389,14 @@ static int try_to_take_rt_mutex(struct r
 	 * 3) it is top waiter
 	 */
 	if (rt_mutex_has_waiters(lock)) {
-		if (task->prio >= rt_mutex_top_waiter(lock)->list_entry.prio) {
-			if (!waiter || waiter != rt_mutex_top_waiter(lock))
-				return 0;
-		}
+		struct task_struct *pown = rt_mutex_top_waiter(lock)->task;
+
+		if (task != pown && !lock_is_stealable(task, pown, mode))
+			return 0;
 	}
 
+	/* We got the lock. */
+
 	if (waiter || rt_mutex_has_waiters(lock)) {
 		unsigned long flags;
 		struct rt_mutex_waiter *top;
@@ -371,7 +421,6 @@ static int try_to_take_rt_mutex(struct r
 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 	}
 
-	/* We got the lock. */
 	debug_rt_mutex_lock(lock);
 
 	rt_mutex_set_owner(lock, task);
@@ -381,6 +430,13 @@ static int try_to_take_rt_mutex(struct r
 	return 1;
 }
 
+static inline int
+try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+		     struct rt_mutex_waiter *waiter)
+{
+	return __try_to_take_rt_mutex(lock, task, waiter, STEAL_NORMAL);
+}
+
 /*
  * Task blocks on lock.
  *
@@ -399,6 +455,23 @@ static int task_blocks_on_rt_mutex(struc
 	int chain_walk = 0, res;
 
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
+
+	/*
+	 * In the case of futex requeue PI, this will be a proxy
+	 * lock. The task will wake unaware that it is enqueueed on
+	 * this lock. Avoid blocking on two locks and corrupting
+	 * pi_blocked_on via the PI_WAKEUP_INPROGRESS
+	 * flag. futex_wait_requeue_pi() sets this when it wakes up
+	 * before requeue (due to a signal or timeout). Do not enqueue
+	 * the task if PI_WAKEUP_INPROGRESS is set.
+	 */
+	if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		return -EAGAIN;
+	}
+
+	BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
+
 	__rt_mutex_adjust_prio(task);
 	waiter->task = task;
 	waiter->lock = lock;
@@ -423,7 +496,7 @@ static int task_blocks_on_rt_mutex(struc
 		plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
 
 		__rt_mutex_adjust_prio(owner);
-		if (owner->pi_blocked_on)
+		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
 		raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
 	}
@@ -478,7 +551,7 @@ static void wakeup_next_waiter(struct rt
 
 	raw_spin_unlock_irqrestore(&current->pi_lock, flags);
 
-	wake_up_process(waiter->task);
+	rt_mutex_wake_waiter(waiter);
 }
 
 /*
@@ -517,7 +590,7 @@ static void remove_waiter(struct rt_mute
 		}
 		__rt_mutex_adjust_prio(owner);
 
-		if (owner->pi_blocked_on)
+		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
 
 		raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
@@ -551,23 +624,316 @@ void rt_mutex_adjust_pi(struct task_stru
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
 
 	waiter = task->pi_blocked_on;
-	if (!waiter || waiter->list_entry.prio == task->prio) {
+	if (!rt_mutex_real_waiter(waiter) ||
+	    waiter->list_entry.prio == task->prio) {
 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 		return;
 	}
 
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
-
 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
 	get_task_struct(task);
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+/*
+ * preemptible spin_lock functions:
+ */
+static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
+					 void  (*slowfn)(struct rt_mutex *lock))
+{
+	might_sleep();
+
+	if (likely(rt_mutex_cmpxchg(lock, NULL, current)))
+		rt_mutex_deadlock_account_lock(lock, current);
+	else
+		slowfn(lock);
+}
+
+static inline void rt_spin_lock_fastunlock(struct rt_mutex *lock,
+					   void  (*slowfn)(struct rt_mutex *lock))
+{
+	if (likely(rt_mutex_cmpxchg(lock, current, NULL)))
+		rt_mutex_deadlock_account_unlock(current);
+	else
+		slowfn(lock);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Note that owner is a speculative pointer and dereferencing relies
+ * on rcu_read_lock() and the check against the lock owner.
+ */
+static int adaptive_wait(struct rt_mutex *lock,
+			 struct task_struct *owner)
+{
+	int res = 0;
+
+	rcu_read_lock();
+	for (;;) {
+		if (owner != rt_mutex_owner(lock))
+			break;
+		/*
+		 * Ensure that owner->on_cpu is dereferenced _after_
+		 * checking the above to be valid.
+		 */
+		barrier();
+		if (!owner->on_cpu) {
+			res = 1;
+			break;
+		}
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return res;
+}
+#else
+static int adaptive_wait(struct rt_mutex *lock,
+			 struct task_struct *orig_owner)
+{
+	return 1;
+}
+#endif
+
+# define pi_lock(lock)			raw_spin_lock_irq(lock)
+# define pi_unlock(lock)		raw_spin_unlock_irq(lock)
+
+/*
+ * Slow path lock function spin_lock style: this variant is very
+ * careful not to miss any non-lock wakeups.
+ *
+ * We store the current state under p->pi_lock in p->saved_state and
+ * the try_to_wake_up() code handles this accordingly.
+ */
+static void  noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+{
+	struct task_struct *lock_owner, *self = current;
+	struct rt_mutex_waiter waiter, *top_waiter;
+	int ret;
+
+	rt_mutex_init_waiter(&waiter, true);
+
+	raw_spin_lock(&lock->wait_lock);
+	init_lists(lock);
+
+	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL)) {
+		raw_spin_unlock(&lock->wait_lock);
+		return;
+	}
+
+	BUG_ON(rt_mutex_owner(lock) == self);
+
+	/*
+	 * We save whatever state the task is in and we'll restore it
+	 * after acquiring the lock taking real wakeups into account
+	 * as well. We are serialized via pi_lock against wakeups. See
+	 * try_to_wake_up().
+	 */
+	pi_lock(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state(TASK_UNINTERRUPTIBLE);
+	pi_unlock(&self->pi_lock);
+
+	ret = task_blocks_on_rt_mutex(lock, &waiter, self, 0);
+	BUG_ON(ret);
+
+	for (;;) {
+		/* Try to acquire the lock again. */
+		if (__try_to_take_rt_mutex(lock, self, &waiter, STEAL_LATERAL))
+			break;
+
+		top_waiter = rt_mutex_top_waiter(lock);
+		lock_owner = rt_mutex_owner(lock);
+
+		raw_spin_unlock(&lock->wait_lock);
+
+		debug_rt_mutex_print_deadlock(&waiter);
+
+		if (top_waiter != &waiter || adaptive_wait(lock, lock_owner))
+			schedule_rt_mutex(lock);
+
+		raw_spin_lock(&lock->wait_lock);
+
+		pi_lock(&self->pi_lock);
+		__set_current_state(TASK_UNINTERRUPTIBLE);
+		pi_unlock(&self->pi_lock);
+	}
+
+	/*
+	 * Restore the task state to current->saved_state. We set it
+	 * to the original state above and the try_to_wake_up() code
+	 * has possibly updated it when a real (non-rtmutex) wakeup
+	 * happened while we were blocked. Clear saved_state so
+	 * try_to_wakeup() does not get confused.
+	 */
+	pi_lock(&self->pi_lock);
+	__set_current_state(self->saved_state);
+	self->saved_state = TASK_RUNNING;
+	pi_unlock(&self->pi_lock);
+
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit
+	 * unconditionally. We might have to fix that up:
+	 */
+	fixup_rt_mutex_waiters(lock);
+
+	BUG_ON(rt_mutex_has_waiters(lock) && &waiter == rt_mutex_top_waiter(lock));
+	BUG_ON(!plist_node_empty(&waiter.list_entry));
+
+	raw_spin_unlock(&lock->wait_lock);
+
+	debug_rt_mutex_free_waiter(&waiter);
+}
+
+/*
+ * Slow path to release a rt_mutex spin_lock style
+ */
+static void  noinline __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+{
+	raw_spin_lock(&lock->wait_lock);
+
+	debug_rt_mutex_unlock(lock);
+
+	rt_mutex_deadlock_account_unlock(current);
+
+	if (!rt_mutex_has_waiters(lock)) {
+		lock->owner = NULL;
+		raw_spin_unlock(&lock->wait_lock);
+		return;
+	}
+
+	wakeup_next_waiter(lock);
+
+	raw_spin_unlock(&lock->wait_lock);
+
+	/* Undo pi boosting.when necessary */
+	rt_mutex_adjust_prio(current);
+}
+
+void __lockfunc rt_spin_lock(spinlock_t *lock)
+{
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
+{
+	rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(__rt_spin_lock);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+}
+EXPORT_SYMBOL(rt_spin_lock_nested);
+#endif
+
+void __lockfunc rt_spin_unlock(spinlock_t *lock)
+{
+	/* NOTE: we always pass in '1' for nested, for simplicity */
+	spin_release(&lock->dep_map, 1, _RET_IP_);
+	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+}
+EXPORT_SYMBOL(rt_spin_unlock);
+
+void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
+{
+	rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
+}
+EXPORT_SYMBOL(__rt_spin_unlock);
+
+/*
+ * Wait for the lock to get unlocked: instead of polling for an unlock
+ * (like raw spinlocks do), we lock and unlock, to force the kernel to
+ * schedule if there's contention:
+ */
+void __lockfunc rt_spin_unlock_wait(spinlock_t *lock)
+{
+	spin_lock(lock);
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_unlock_wait);
+
+int __lockfunc rt_spin_trylock(spinlock_t *lock)
+{
+	int ret = rt_mutex_trylock(&lock->lock);
+
+	if (ret)
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock);
+
+int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
+{
+	int ret;
+
+	local_bh_disable();
+	ret = rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		migrate_disable();
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	} else
+		local_bh_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_bh);
+
+int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
+{
+	int ret;
+
+	*flags = 0;
+	migrate_disable();
+	ret = rt_mutex_trylock(&lock->lock);
+	if (ret)
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	else
+		migrate_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_irqsave);
+
+int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock)
+{
+	/* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
+	if (atomic_add_unless(atomic, -1, 1))
+		return 0;
+	migrate_disable();
+	rt_spin_lock(lock);
+	if (atomic_dec_and_test(atomic))
+		return 1;
+	rt_spin_unlock(lock);
+	migrate_enable();
+	return 0;
+}
+EXPORT_SYMBOL(atomic_dec_and_spin_lock);
+
+void
+__rt_spin_lock_init(spinlock_t *lock, char *name, struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+
+#endif /* PREEMPT_RT_FULL */
+
 /**
  * __rt_mutex_slowlock() - Perform the wait-wake-try-to-take loop
  * @lock:		 the rt_mutex to take
  * @state:		 the state the task should block in (TASK_INTERRUPTIBLE
- * 			 or TASK_UNINTERRUPTIBLE)
+ *			 or TASK_UNINTERRUPTIBLE)
  * @timeout:		 the pre-initialized and started timer, or NULL for none
  * @waiter:		 the pre-initialized rt_mutex_waiter
  *
@@ -623,9 +989,10 @@ rt_mutex_slowlock(struct rt_mutex *lock,
 	struct rt_mutex_waiter waiter;
 	int ret = 0;
 
-	debug_rt_mutex_init_waiter(&waiter);
+	rt_mutex_init_waiter(&waiter, false);
 
 	raw_spin_lock(&lock->wait_lock);
+	init_lists(lock);
 
 	/* Try to acquire the lock again: */
 	if (try_to_take_rt_mutex(lock, current, NULL)) {
@@ -678,6 +1045,7 @@ rt_mutex_slowtrylock(struct rt_mutex *lo
 	int ret = 0;
 
 	raw_spin_lock(&lock->wait_lock);
+	init_lists(lock);
 
 	if (likely(rt_mutex_owner(lock) != current)) {
 
@@ -791,12 +1159,12 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
 /**
  * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
  *
- * @lock: 		the rt_mutex to be locked
+ * @lock:		the rt_mutex to be locked
  * @detect_deadlock:	deadlock detection on/off
  *
  * Returns:
- *  0 		on success
- * -EINTR 	when interrupted by a signal
+ *  0		on success
+ * -EINTR	when interrupted by a signal
  * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
@@ -810,17 +1178,38 @@ int __sched rt_mutex_lock_interruptible(
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
 /**
+ * rt_mutex_lock_killable - lock a rt_mutex killable
+ *
+ * @lock:		the rt_mutex to be locked
+ * @detect_deadlock:	deadlock detection on/off
+ *
+ * Returns:
+ *  0		on success
+ * -EINTR	when interrupted by a signal
+ * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock,
+				   int detect_deadlock)
+{
+	might_sleep();
+
+	return rt_mutex_fastlock(lock, TASK_KILLABLE,
+				 detect_deadlock, rt_mutex_slowlock);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
+/**
  * rt_mutex_timed_lock - lock a rt_mutex interruptible
  *			the timeout structure is provided
  *			by the caller
  *
- * @lock: 		the rt_mutex to be locked
+ * @lock:		the rt_mutex to be locked
  * @timeout:		timeout structure or NULL (no timeout)
  * @detect_deadlock:	deadlock detection on/off
  *
  * Returns:
- *  0 		on success
- * -EINTR 	when interrupted by a signal
+ *  0		on success
+ * -EINTR	when interrupted by a signal
  * -ETIMEDOUT	when the timeout expired
  * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
  */
@@ -889,12 +1278,11 @@ EXPORT_SYMBOL_GPL(rt_mutex_destroy);
 void __rt_mutex_init(struct rt_mutex *lock, const char *name)
 {
 	lock->owner = NULL;
-	raw_spin_lock_init(&lock->wait_lock);
 	plist_head_init(&lock->wait_list);
 
 	debug_rt_mutex_init(lock, name);
 }
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
+EXPORT_SYMBOL(__rt_mutex_init);
 
 /**
  * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
@@ -909,7 +1297,7 @@ EXPORT_SYMBOL_GPL(__rt_mutex_init);
 void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				struct task_struct *proxy_owner)
 {
-	__rt_mutex_init(lock, NULL);
+	rt_mutex_init(lock);
 	debug_rt_mutex_proxy_lock(lock, proxy_owner);
 	rt_mutex_set_owner(lock, proxy_owner);
 	rt_mutex_deadlock_account_lock(lock, proxy_owner);
@@ -958,6 +1346,35 @@ int rt_mutex_start_proxy_lock(struct rt_
 		return 1;
 	}
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+	/*
+	 * In PREEMPT_RT there's an added race.
+	 * If the task, that we are about to requeue, times out,
+	 * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
+	 * to skip this task. But right after the task sets
+	 * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
+	 * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
+	 * This will replace the PI_WAKEUP_INPROGRESS with the actual
+	 * lock that it blocks on. We *must not* place this task
+	 * on this proxy lock in that case.
+	 *
+	 * To prevent this race, we first take the task's pi_lock
+	 * and check if it has updated its pi_blocked_on. If it has,
+	 * we assume that it woke up and we return -EAGAIN.
+	 * Otherwise, we set the task's pi_blocked_on to
+	 * PI_REQUEUE_INPROGRESS, so that if the task is waking up
+	 * it will know that we are in the process of requeuing it.
+	 */
+	raw_spin_lock_irq(&task->pi_lock);
+	if (task->pi_blocked_on) {
+		raw_spin_unlock_irq(&task->pi_lock);
+		raw_spin_unlock(&lock->wait_lock);
+		return -EAGAIN;
+	}
+	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
+	raw_spin_unlock_irq(&task->pi_lock);
+#endif
+
 	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
 
 	if (ret && !rt_mutex_owner(lock)) {
Index: linux-3.4/kernel/futex.c
===================================================================
--- linux-3.4.orig/kernel/futex.c
+++ linux-3.4/kernel/futex.c
@@ -1423,6 +1423,16 @@ retry_private:
 				requeue_pi_wake_futex(this, &key2, hb2);
 				drop_count++;
 				continue;
+			} else if (ret == -EAGAIN) {
+				/*
+				 * Waiter was woken by timeout or
+				 * signal and has set pi_blocked_on to
+				 * PI_WAKEUP_INPROGRESS before we
+				 * tried to enqueue it on the rtmutex.
+				 */
+				this->pi_state = NULL;
+				free_pi_state(pi_state);
+				continue;
 			} else if (ret) {
 				/* -EDEADLK */
 				this->pi_state = NULL;
@@ -2267,7 +2277,7 @@ static int futex_wait_requeue_pi(u32 __u
 	struct hrtimer_sleeper timeout, *to = NULL;
 	struct rt_mutex_waiter rt_waiter;
 	struct rt_mutex *pi_mutex = NULL;
-	struct futex_hash_bucket *hb;
+	struct futex_hash_bucket *hb, *hb2;
 	union futex_key key2 = FUTEX_KEY_INIT;
 	struct futex_q q = futex_q_init;
 	int res, ret;
@@ -2289,8 +2299,7 @@ static int futex_wait_requeue_pi(u32 __u
 	 * The waiter is allocated on our stack, manipulated by the requeue
 	 * code while we sleep on uaddr.
 	 */
-	debug_rt_mutex_init_waiter(&rt_waiter);
-	rt_waiter.task = NULL;
+	rt_mutex_init_waiter(&rt_waiter, false);
 
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, VERIFY_WRITE);
 	if (unlikely(ret != 0))
@@ -2311,20 +2320,55 @@ static int futex_wait_requeue_pi(u32 __u
 	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
 	futex_wait_queue_me(hb, &q, to);
 
-	spin_lock(&hb->lock);
-	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
-	spin_unlock(&hb->lock);
-	if (ret)
-		goto out_put_keys;
+	/*
+	 * On RT we must avoid races with requeue and trying to block
+	 * on two mutexes (hb->lock and uaddr2's rtmutex) by
+	 * serializing access to pi_blocked_on with pi_lock.
+	 */
+	raw_spin_lock_irq(&current->pi_lock);
+	if (current->pi_blocked_on) {
+		/*
+		 * We have been requeued or are in the process of
+		 * being requeued.
+		 */
+		raw_spin_unlock_irq(&current->pi_lock);
+	} else {
+		/*
+		 * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
+		 * prevents a concurrent requeue from moving us to the
+		 * uaddr2 rtmutex. After that we can safely acquire
+		 * (and possibly block on) hb->lock.
+		 */
+		current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
+		raw_spin_unlock_irq(&current->pi_lock);
+
+		spin_lock(&hb->lock);
+
+		/*
+		 * Clean up pi_blocked_on. We might leak it otherwise
+		 * when we succeeded with the hb->lock in the fast
+		 * path.
+		 */
+		raw_spin_lock_irq(&current->pi_lock);
+		current->pi_blocked_on = NULL;
+		raw_spin_unlock_irq(&current->pi_lock);
+
+		ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+		spin_unlock(&hb->lock);
+		if (ret)
+			goto out_put_keys;
+	}
 
 	/*
-	 * In order for us to be here, we know our q.key == key2, and since
-	 * we took the hb->lock above, we also know that futex_requeue() has
-	 * completed and we no longer have to concern ourselves with a wakeup
-	 * race with the atomic proxy lock acquisition by the requeue code. The
-	 * futex_requeue dropped our key1 reference and incremented our key2
-	 * reference count.
+	 * In order to be here, we have either been requeued, are in
+	 * the process of being requeued, or requeue successfully
+	 * acquired uaddr2 on our behalf.  If pi_blocked_on was
+	 * non-null above, we may be racing with a requeue.  Do not
+	 * rely on q->lock_ptr to be hb2->lock until after blocking on
+	 * hb->lock or hb2->lock. The futex_requeue dropped our key1
+	 * reference and incremented our key2 reference count.
 	 */
+	hb2 = hash_futex(&key2);
 
 	/* Check if the requeue code acquired the second futex for us. */
 	if (!q.rt_waiter) {
@@ -2333,9 +2377,10 @@ static int futex_wait_requeue_pi(u32 __u
 		 * did a lock-steal - fix up the PI-state in that case.
 		 */
 		if (q.pi_state && (q.pi_state->owner != current)) {
-			spin_lock(q.lock_ptr);
+			spin_lock(&hb2->lock);
+			BUG_ON(&hb2->lock != q.lock_ptr);
 			ret = fixup_pi_state_owner(uaddr2, &q, current);
-			spin_unlock(q.lock_ptr);
+			spin_unlock(&hb2->lock);
 		}
 	} else {
 		/*
@@ -2348,7 +2393,8 @@ static int futex_wait_requeue_pi(u32 __u
 		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
 		debug_rt_mutex_free_waiter(&rt_waiter);
 
-		spin_lock(q.lock_ptr);
+		spin_lock(&hb2->lock);
+		BUG_ON(&hb2->lock != q.lock_ptr);
 		/*
 		 * Fixup the pi_state owner and possibly acquire the lock if we
 		 * haven't already.
Index: linux-3.4/kernel/rtmutex_common.h
===================================================================
--- linux-3.4.orig/kernel/rtmutex_common.h
+++ linux-3.4/kernel/rtmutex_common.h
@@ -49,6 +49,7 @@ struct rt_mutex_waiter {
 	struct plist_node	pi_list_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
+	bool			savestate;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
@@ -103,6 +104,9 @@ static inline struct task_struct *rt_mut
 /*
  * PI-futex support (proxy locking functions, etc.):
  */
+#define PI_WAKEUP_INPROGRESS	((struct rt_mutex_waiter *) 1)
+#define PI_REQUEUE_INPROGRESS	((struct rt_mutex_waiter *) 2)
+
 extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
 extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				       struct task_struct *proxy_owner);
@@ -123,4 +127,12 @@ extern int rt_mutex_finish_proxy_lock(st
 # include "rtmutex.h"
 #endif
 
+static inline void
+rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
+{
+	debug_rt_mutex_init_waiter(waiter);
+	waiter->task = NULL;
+	waiter->savestate = savestate;
+}
+
 #endif
Index: linux-3.4/include/linux/rwlock_types.h
===================================================================
--- linux-3.4.orig/include/linux/rwlock_types.h
+++ linux-3.4/include/linux/rwlock_types.h
@@ -1,6 +1,10 @@
 #ifndef __LINUX_RWLOCK_TYPES_H
 #define __LINUX_RWLOCK_TYPES_H
 
+#if !defined(__LINUX_SPINLOCK_TYPES_H)
+# error "Do not include directly, include spinlock_types.h"
+#endif
+
 /*
  * include/linux/rwlock_types.h - generic rwlock type definitions
  *				  and initializers
@@ -43,6 +47,7 @@ typedef struct {
 				RW_DEP_MAP_INIT(lockname) }
 #endif
 
-#define DEFINE_RWLOCK(x)	rwlock_t x = __RW_LOCK_UNLOCKED(x)
+#define DEFINE_RWLOCK(name) \
+	rwlock_t name __cacheline_aligned_in_smp = __RW_LOCK_UNLOCKED(name)
 
 #endif /* __LINUX_RWLOCK_TYPES_H */
Index: linux-3.4/include/linux/spinlock_types.h
===================================================================
--- linux-3.4.orig/include/linux/spinlock_types.h
+++ linux-3.4/include/linux/spinlock_types.h
@@ -9,80 +9,15 @@
  * Released under the General Public License (GPL).
  */
 
-#if defined(CONFIG_SMP)
-# include <asm/spinlock_types.h>
-#else
-# include <linux/spinlock_types_up.h>
-#endif
-
-#include <linux/lockdep.h>
-
-typedef struct raw_spinlock {
-	arch_spinlock_t raw_lock;
-#ifdef CONFIG_GENERIC_LOCKBREAK
-	unsigned int break_lock;
-#endif
-#ifdef CONFIG_DEBUG_SPINLOCK
-	unsigned int magic, owner_cpu;
-	void *owner;
-#endif
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	struct lockdep_map dep_map;
-#endif
-} raw_spinlock_t;
-
-#define SPINLOCK_MAGIC		0xdead4ead
-
-#define SPINLOCK_OWNER_INIT	((void *)-1L)
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
-#else
-# define SPIN_DEP_MAP_INIT(lockname)
-#endif
+#include <linux/spinlock_types_raw.h>
 
-#ifdef CONFIG_DEBUG_SPINLOCK
-# define SPIN_DEBUG_INIT(lockname)		\
-	.magic = SPINLOCK_MAGIC,		\
-	.owner_cpu = -1,			\
-	.owner = SPINLOCK_OWNER_INIT,
+#ifndef CONFIG_PREEMPT_RT_FULL
+# include <linux/spinlock_types_nort.h>
+# include <linux/rwlock_types.h>
 #else
-# define SPIN_DEBUG_INIT(lockname)
+# include <linux/rtmutex.h>
+# include <linux/spinlock_types_rt.h>
+# include <linux/rwlock_types_rt.h>
 #endif
 
-#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
-	{					\
-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
-	SPIN_DEBUG_INIT(lockname)		\
-	SPIN_DEP_MAP_INIT(lockname) }
-
-#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
-	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
-
-#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
-
-typedef struct spinlock {
-	union {
-		struct raw_spinlock rlock;
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
-		struct {
-			u8 __padding[LOCK_PADSIZE];
-			struct lockdep_map dep_map;
-		};
-#endif
-	};
-} spinlock_t;
-
-#define __SPIN_LOCK_INITIALIZER(lockname) \
-	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
-
-#define __SPIN_LOCK_UNLOCKED(lockname) \
-	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
-
-#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
-
-#include <linux/rwlock_types.h>
-
 #endif /* __LINUX_SPINLOCK_TYPES_H */
Index: linux-3.4/include/linux/spinlock_types_nort.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/spinlock_types_nort.h
@@ -0,0 +1,33 @@
+#ifndef __LINUX_SPINLOCK_TYPES_NORT_H
+#define __LINUX_SPINLOCK_TYPES_NORT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+/*
+ * The non RT version maps spinlocks to raw_spinlocks
+ */
+typedef struct spinlock {
+	union {
+		struct raw_spinlock rlock;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
+		struct {
+			u8 __padding[LOCK_PADSIZE];
+			struct lockdep_map dep_map;
+		};
+#endif
+	};
+} spinlock_t;
+
+#define __SPIN_LOCK_INITIALIZER(lockname) \
+	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
+
+#define __SPIN_LOCK_UNLOCKED(lockname) \
+	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
+
+#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
+
+#endif
Index: linux-3.4/include/linux/spinlock_types_raw.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/spinlock_types_raw.h
@@ -0,0 +1,56 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
+#define __LINUX_SPINLOCK_TYPES_RAW_H
+
+#if defined(CONFIG_SMP)
+# include <asm/spinlock_types.h>
+#else
+# include <linux/spinlock_types_up.h>
+#endif
+
+#include <linux/lockdep.h>
+
+typedef struct raw_spinlock {
+	arch_spinlock_t raw_lock;
+#ifdef CONFIG_GENERIC_LOCKBREAK
+	unsigned int break_lock;
+#endif
+#ifdef CONFIG_DEBUG_SPINLOCK
+	unsigned int magic, owner_cpu;
+	void *owner;
+#endif
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map dep_map;
+#endif
+} raw_spinlock_t;
+
+#define SPINLOCK_MAGIC		0xdead4ead
+
+#define SPINLOCK_OWNER_INIT	((void *)-1L)
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define SPIN_DEP_MAP_INIT(lockname)
+#endif
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+# define SPIN_DEBUG_INIT(lockname)		\
+	.magic = SPINLOCK_MAGIC,		\
+	.owner_cpu = -1,			\
+	.owner = SPINLOCK_OWNER_INIT,
+#else
+# define SPIN_DEBUG_INIT(lockname)
+#endif
+
+#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
+	{					\
+	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+	SPIN_DEBUG_INIT(lockname)		\
+	SPIN_DEP_MAP_INIT(lockname) }
+
+#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
+	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
+
+#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
+
+#endif
Index: linux-3.4/include/linux/rwlock_types_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/rwlock_types_rt.h
@@ -0,0 +1,33 @@
+#ifndef __LINUX_RWLOCK_TYPES_RT_H
+#define __LINUX_RWLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+/*
+ * rwlocks - rtmutex which allows single reader recursion
+ */
+typedef struct {
+	struct rt_mutex		lock;
+	int			read_depth;
+	unsigned int		break_lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+} rwlock_t;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define RW_DEP_MAP_INIT(lockname)
+#endif
+
+#define __RW_LOCK_UNLOCKED(name) \
+	{ .lock = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.lock),	\
+	  RW_DEP_MAP_INIT(name) }
+
+#define DEFINE_RWLOCK(name) \
+	rwlock_t name __cacheline_aligned_in_smp = __RW_LOCK_UNLOCKED(name)
+
+#endif
Index: linux-3.4/include/linux/spinlock_types_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/spinlock_types_rt.h
@@ -0,0 +1,49 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RT_H
+#define __LINUX_SPINLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+/*
+ * PREEMPT_RT: spinlocks - an RT mutex plus lock-break field:
+ */
+typedef struct spinlock {
+	struct rt_mutex		lock;
+	unsigned int		break_lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+} spinlock_t;
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define __RT_SPIN_INITIALIZER(name) \
+	{ \
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
+	.save_state = 1, \
+	.file = __FILE__, \
+	.line = __LINE__ , \
+	}
+#else
+# define __RT_SPIN_INITIALIZER(name) \
+	{								\
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock),		\
+	.save_state = 1, \
+	}
+#endif
+
+/*
+.wait_list = PLIST_HEAD_INIT_RAW((name).lock.wait_list, (name).lock.wait_lock)
+*/
+
+#define __SPIN_LOCK_UNLOCKED(name)			\
+	{ .lock = __RT_SPIN_INITIALIZER(name.lock),		\
+	  SPIN_DEP_MAP_INIT(name) }
+
+#define __DEFINE_SPINLOCK(name) \
+	spinlock_t name = __SPIN_LOCK_UNLOCKED(name)
+
+#define DEFINE_SPINLOCK(name) \
+	spinlock_t name __cacheline_aligned_in_smp = __SPIN_LOCK_UNLOCKED(name)
+
+#endif
Index: linux-3.4/include/linux/mutex.h
===================================================================
--- linux-3.4.orig/include/linux/mutex.h
+++ linux-3.4/include/linux/mutex.h
@@ -17,6 +17,17 @@
 
 #include <linux/atomic.h>
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
+		, .dep_map = { .name = #lockname }
+#else
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+#endif
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/mutex_rt.h>
+#else
+
 /*
  * Simple, straightforward mutexes with strict semantics:
  *
@@ -95,13 +106,6 @@ do {							\
 static inline void mutex_destroy(struct mutex *lock) {}
 #endif
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
-		, .dep_map = { .name = #lockname }
-#else
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
-#endif
-
 #define __MUTEX_INITIALIZER(lockname) \
 		{ .count = ATOMIC_INIT(1) \
 		, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
@@ -167,6 +171,9 @@ extern int __must_check mutex_lock_killa
  */
 extern int mutex_trylock(struct mutex *lock);
 extern void mutex_unlock(struct mutex *lock);
+
+#endif /* !PREEMPT_RT_FULL */
+
 extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
 
 #ifndef CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX
Index: linux-3.4/include/linux/mutex_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/mutex_rt.h
@@ -0,0 +1,84 @@
+#ifndef __LINUX_MUTEX_RT_H
+#define __LINUX_MUTEX_RT_H
+
+#ifndef __LINUX_MUTEX_H
+#error "Please include mutex.h"
+#endif
+
+#include <linux/rtmutex.h>
+
+/* FIXME: Just for __lockfunc */
+#include <linux/spinlock.h>
+
+struct mutex {
+	struct rt_mutex		lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define __MUTEX_INITIALIZER(mutexname)					\
+	{								\
+		.lock = __RT_MUTEX_INITIALIZER(mutexname.lock)		\
+		__DEP_MAP_MUTEX_INITIALIZER(mutexname)			\
+	}
+
+#define DEFINE_MUTEX(mutexname)						\
+	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
+
+extern void __mutex_do_init(struct mutex *lock, const char *name, struct lock_class_key *key);
+extern void __lockfunc _mutex_lock(struct mutex *lock);
+extern int __lockfunc _mutex_lock_interruptible(struct mutex *lock);
+extern int __lockfunc _mutex_lock_killable(struct mutex *lock);
+extern void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass);
+extern void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);
+extern int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_trylock(struct mutex *lock);
+extern void __lockfunc _mutex_unlock(struct mutex *lock);
+
+#define mutex_is_locked(l)		rt_mutex_is_locked(&(l)->lock)
+#define mutex_lock(l)			_mutex_lock(l)
+#define mutex_lock_interruptible(l)	_mutex_lock_interruptible(l)
+#define mutex_lock_killable(l)		_mutex_lock_killable(l)
+#define mutex_trylock(l)		_mutex_trylock(l)
+#define mutex_unlock(l)			_mutex_unlock(l)
+#define mutex_destroy(l)		rt_mutex_destroy(&(l)->lock)
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define mutex_lock_nested(l, s)	_mutex_lock_nested(l, s)
+# define mutex_lock_interruptible_nested(l, s) \
+					_mutex_lock_interruptible_nested(l, s)
+# define mutex_lock_killable_nested(l, s) \
+					_mutex_lock_killable_nested(l, s)
+
+# define mutex_lock_nest_lock(lock, nest_lock)				\
+do {									\
+	typecheck(struct lockdep_map *, &(nest_lock)->dep_map);		\
+	_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map);		\
+} while (0)
+
+#else
+# define mutex_lock_nested(l, s)	_mutex_lock(l)
+# define mutex_lock_interruptible_nested(l, s) \
+					_mutex_lock_interruptible(l)
+# define mutex_lock_killable_nested(l, s) \
+					_mutex_lock_killable(l)
+# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
+#endif
+
+# define mutex_init(mutex)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(mutex)->lock);			\
+	__mutex_do_init((mutex), #mutex, &__key);	\
+} while (0)
+
+# define __mutex_init(mutex, name, key)			\
+do {							\
+	rt_mutex_init(&(mutex)->lock);			\
+	__mutex_do_init((mutex), name, key);		\
+} while (0)
+
+#endif
Index: linux-3.4/include/linux/rwsem.h
===================================================================
--- linux-3.4.orig/include/linux/rwsem.h
+++ linux-3.4/include/linux/rwsem.h
@@ -16,6 +16,10 @@
 
 #include <linux/atomic.h>
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+#include <linux/rwsem_rt.h>
+#else /* PREEMPT_RT_FULL */
+
 struct rw_semaphore;
 
 #ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
@@ -130,4 +134,6 @@ extern void down_write_nested(struct rw_
 # define down_write_nested(sem, subclass)	down_write(sem)
 #endif
 
+#endif /* !PREEMPT_RT_FULL */
+
 #endif /* _LINUX_RWSEM_H */
Index: linux-3.4/include/linux/rwsem_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/rwsem_rt.h
@@ -0,0 +1,105 @@
+#ifndef _LINUX_RWSEM_RT_H
+#define _LINUX_RWSEM_RT_H
+
+#ifndef _LINUX_RWSEM_H
+#error "Include rwsem.h"
+#endif
+
+/*
+ * RW-semaphores are a spinlock plus a reader-depth count.
+ *
+ * Note that the semantics are different from the usual
+ * Linux rw-sems, in PREEMPT_RT mode we do not allow
+ * multiple readers to hold the lock at once, we only allow
+ * a read-lock owner to read-lock recursively. This is
+ * better for latency, makes the implementation inherently
+ * fair and makes it simpler as well.
+ */
+
+#include <linux/rtmutex.h>
+
+struct rw_semaphore {
+	struct rt_mutex		lock;
+	int			read_depth;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define __RWSEM_INITIALIZER(name) \
+	{ .lock = __RT_MUTEX_INITIALIZER(name.lock), \
+	  RW_DEP_MAP_INIT(name) }
+
+#define DECLARE_RWSEM(lockname) \
+	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
+
+extern void  __rt_rwsem_init(struct rw_semaphore *rwsem, char *name,
+				     struct lock_class_key *key);
+
+# define rt_init_rwsem(sem)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(sem)->lock);			\
+	__rt_rwsem_init((sem), #sem, &__key);		\
+} while (0)
+
+extern void  rt_down_write(struct rw_semaphore *rwsem);
+extern void rt_down_read_nested(struct rw_semaphore *rwsem, int subclass);
+extern void rt_down_write_nested(struct rw_semaphore *rwsem, int subclass);
+extern void  rt_down_read(struct rw_semaphore *rwsem);
+extern int  rt_down_write_trylock(struct rw_semaphore *rwsem);
+extern int  rt_down_read_trylock(struct rw_semaphore *rwsem);
+extern void  rt_up_read(struct rw_semaphore *rwsem);
+extern void  rt_up_write(struct rw_semaphore *rwsem);
+extern void  rt_downgrade_write(struct rw_semaphore *rwsem);
+
+#define init_rwsem(sem)		rt_init_rwsem(sem)
+#define rwsem_is_locked(s)	rt_mutex_is_locked(&(s)->lock)
+
+static inline void down_read(struct rw_semaphore *sem)
+{
+	rt_down_read(sem);
+}
+
+static inline int down_read_trylock(struct rw_semaphore *sem)
+{
+	return rt_down_read_trylock(sem);
+}
+
+static inline void down_write(struct rw_semaphore *sem)
+{
+	rt_down_write(sem);
+}
+
+static inline int down_write_trylock(struct rw_semaphore *sem)
+{
+	return rt_down_write_trylock(sem);
+}
+
+static inline void up_read(struct rw_semaphore *sem)
+{
+	rt_up_read(sem);
+}
+
+static inline void up_write(struct rw_semaphore *sem)
+{
+	rt_up_write(sem);
+}
+
+static inline void downgrade_write(struct rw_semaphore *sem)
+{
+	rt_downgrade_write(sem);
+}
+
+static inline void down_read_nested(struct rw_semaphore *sem, int subclass)
+{
+	return rt_down_read_nested(sem, subclass);
+}
+
+static inline void down_write_nested(struct rw_semaphore *sem, int subclass)
+{
+	rt_down_write_nested(sem, subclass);
+}
+
+#endif
Index: linux-3.4/lib/Makefile
===================================================================
--- linux-3.4.orig/lib/Makefile
+++ linux-3.4/lib/Makefile
@@ -38,8 +38,11 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o 
 obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
 obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
+
+ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
+endif
 
 CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
 obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
Index: linux-3.4/include/linux/rwlock_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/rwlock_rt.h
@@ -0,0 +1,123 @@
+#ifndef __LINUX_RWLOCK_RT_H
+#define __LINUX_RWLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+#define rwlock_init(rwl)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(rwl)->lock);			\
+	__rt_rwlock_init(rwl, #rwl, &__key);		\
+} while (0)
+
+extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_trylock_irqsave(rwlock_t *trylock, unsigned long *flags);
+extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
+extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
+extern unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock);
+extern unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock);
+extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
+
+#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
+#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
+
+#define write_trylock_irqsave(lock, flags)	\
+	__cond_lock(lock, rt_write_trylock_irqsave(lock, &flags))
+
+#define read_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		migrate_disable();			\
+		flags = rt_read_lock_irqsave(lock);	\
+	} while (0)
+
+#define write_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		migrate_disable();			\
+		flags = rt_write_lock_irqsave(lock);	\
+	} while (0)
+
+#define read_lock(lock)					\
+	do {						\
+		migrate_disable();			\
+		rt_read_lock(lock);			\
+	} while (0)
+
+#define read_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		migrate_disable();			\
+		rt_read_lock(lock);			\
+	} while (0)
+
+#define read_lock_irq(lock)	read_lock(lock)
+
+#define write_lock(lock)				\
+	do {						\
+		migrate_disable();			\
+		rt_write_lock(lock);			\
+	} while (0)
+
+#define write_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		migrate_disable();			\
+		rt_write_lock(lock);			\
+	} while (0)
+
+#define write_lock_irq(lock)	write_lock(lock)
+
+#define read_unlock(lock)				\
+	do {						\
+		rt_read_unlock(lock);			\
+		migrate_enable();			\
+	} while (0)
+
+#define read_unlock_bh(lock)				\
+	do {						\
+		rt_read_unlock(lock);			\
+		migrate_enable();			\
+		local_bh_enable();			\
+	} while (0)
+
+#define read_unlock_irq(lock)	read_unlock(lock)
+
+#define write_unlock(lock)				\
+	do {						\
+		rt_write_unlock(lock);			\
+		migrate_enable();			\
+	} while (0)
+
+#define write_unlock_bh(lock)				\
+	do {						\
+		rt_write_unlock(lock);			\
+		migrate_enable();			\
+		local_bh_enable();			\
+	} while (0)
+
+#define write_unlock_irq(lock)	write_unlock(lock)
+
+#define read_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		rt_read_unlock(lock);			\
+		migrate_enable();			\
+	} while (0)
+
+#define write_unlock_irqrestore(lock, flags) \
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		rt_write_unlock(lock);			\
+		migrate_enable();			\
+	} while (0)
+
+#endif
Index: linux-3.4/include/linux/spinlock.h
===================================================================
--- linux-3.4.orig/include/linux/spinlock.h
+++ linux-3.4/include/linux/spinlock.h
@@ -254,7 +254,11 @@ static inline void do_raw_spin_unlock(ra
 #define raw_spin_can_lock(lock)	(!raw_spin_is_locked(lock))
 
 /* Include rwlock functions */
-#include <linux/rwlock.h>
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/rwlock_rt.h>
+#else
+# include <linux/rwlock.h>
+#endif
 
 /*
  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@@ -265,6 +269,10 @@ static inline void do_raw_spin_unlock(ra
 # include <linux/spinlock_api_up.h>
 #endif
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+# include <linux/spinlock_rt.h>
+#else /* PREEMPT_RT_FULL */
+
 /*
  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  */
@@ -394,4 +402,6 @@ extern int _atomic_dec_and_lock(atomic_t
 #define atomic_dec_and_lock(atomic, lock) \
 		__cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 
+#endif /* !PREEMPT_RT_FULL */
+
 #endif /* __LINUX_SPINLOCK_H */
Index: linux-3.4/include/linux/spinlock_api_smp.h
===================================================================
--- linux-3.4.orig/include/linux/spinlock_api_smp.h
+++ linux-3.4/include/linux/spinlock_api_smp.h
@@ -191,6 +191,8 @@ static inline int __raw_spin_trylock_bh(
 	return 0;
 }
 
-#include <linux/rwlock_api_smp.h>
+#ifndef CONFIG_PREEMPT_RT_FULL
+# include <linux/rwlock_api_smp.h>
+#endif
 
 #endif /* __LINUX_SPINLOCK_API_SMP_H */
Index: linux-3.4/include/linux/spinlock_rt.h
===================================================================
--- /dev/null
+++ linux-3.4/include/linux/spinlock_rt.h
@@ -0,0 +1,166 @@
+#ifndef __LINUX_SPINLOCK_RT_H
+#define __LINUX_SPINLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+extern void
+__rt_spin_lock_init(spinlock_t *lock, char *name, struct lock_class_key *key);
+
+#define spin_lock_init(slock)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(slock)->lock);			\
+	__rt_spin_lock_init(slock, #slock, &__key);	\
+} while (0)
+
+extern void __lockfunc rt_spin_lock(spinlock_t *lock);
+extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
+extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
+extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
+extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
+extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock(spinlock_t *lock);
+extern int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock);
+
+/*
+ * lockdep-less calls, for derived types like rwlock:
+ * (for trylock they can use rt_mutex_trylock() directly.
+ */
+extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
+
+#define spin_lock_local(lock)			rt_spin_lock(lock)
+#define spin_unlock_local(lock)			rt_spin_unlock(lock)
+
+#define spin_lock(lock)				\
+	do {					\
+		migrate_disable();		\
+		rt_spin_lock(lock);		\
+	} while (0)
+
+#define spin_lock_bh(lock)			\
+	do {					\
+		local_bh_disable();		\
+		migrate_disable();		\
+		rt_spin_lock(lock);		\
+	} while (0)
+
+#define spin_lock_irq(lock)		spin_lock(lock)
+
+#define spin_do_trylock(lock)		__cond_lock(lock, rt_spin_trylock(lock))
+
+#define spin_trylock(lock)			\
+({						\
+	int __locked;				\
+	migrate_disable();			\
+	__locked = spin_do_trylock(lock);	\
+	if (!__locked)				\
+		migrate_enable();		\
+	__locked;				\
+})
+
+#ifdef CONFIG_LOCKDEP
+# define spin_lock_nested(lock, subclass)		\
+	do {						\
+		migrate_disable();			\
+		rt_spin_lock_nested(lock, subclass);	\
+	} while (0)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		migrate_disable();			 \
+		rt_spin_lock_nested(lock, subclass);	 \
+	} while (0)
+#else
+# define spin_lock_nested(lock, subclass)	spin_lock(lock)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		spin_lock(lock);			 \
+	} while (0)
+#endif
+
+#define spin_lock_irqsave(lock, flags)			 \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		spin_lock(lock);			 \
+	} while (0)
+
+static inline unsigned long spin_lock_trace_flags(spinlock_t *lock)
+{
+	unsigned long flags = 0;
+#ifdef CONFIG_TRACE_IRQFLAGS
+	flags = rt_spin_lock_trace_flags(lock);
+#else
+	spin_lock(lock); /* lock_local */
+#endif
+	return flags;
+}
+
+/* FIXME: we need rt_spin_lock_nest_lock */
+#define spin_lock_nest_lock(lock, nest_lock) spin_lock_nested(lock, 0)
+
+#define spin_unlock(lock)				\
+	do {						\
+		rt_spin_unlock(lock);			\
+		migrate_enable();			\
+	} while (0)
+
+#define spin_unlock_bh(lock)				\
+	do {						\
+		rt_spin_unlock(lock);			\
+		migrate_enable();			\
+		local_bh_enable();			\
+	} while (0)
+
+#define spin_unlock_irq(lock)		spin_unlock(lock)
+
+#define spin_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		spin_unlock(lock);			\
+	} while (0)
+
+#define spin_trylock_bh(lock)	__cond_lock(lock, rt_spin_trylock_bh(lock))
+#define spin_trylock_irq(lock)	spin_trylock(lock)
+
+#define spin_trylock_irqsave(lock, flags)	\
+	rt_spin_trylock_irqsave(lock, &(flags))
+
+#define spin_unlock_wait(lock)		rt_spin_unlock_wait(lock)
+
+#ifdef CONFIG_GENERIC_LOCKBREAK
+# define spin_is_contended(lock)	((lock)->break_lock)
+#else
+# define spin_is_contended(lock)	(((void)(lock), 0))
+#endif
+
+static inline int spin_can_lock(spinlock_t *lock)
+{
+	return !rt_mutex_is_locked(&lock->lock);
+}
+
+static inline int spin_is_locked(spinlock_t *lock)
+{
+	return rt_mutex_is_locked(&lock->lock);
+}
+
+static inline void assert_spin_locked(spinlock_t *lock)
+{
+	BUG_ON(!spin_is_locked(lock));
+}
+
+#define atomic_dec_and_lock(atomic, lock) \
+	atomic_dec_and_spin_lock(atomic, lock)
+
+#endif
Index: linux-3.4/kernel/Makefile
===================================================================
--- linux-3.4.orig/kernel/Makefile
+++ linux-3.4/kernel/Makefile
@@ -7,8 +7,8 @@ obj-y     = fork.o exec_domain.o panic.o
 	    sysctl.o sysctl_binary.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o extable.o params.o posix-timers.o \
-	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
-	    hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \
+	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o \
+	    hrtimer.o nsproxy.o srcu.o semaphore.o \
 	    notifier.o ksysfs.o cred.o \
 	    async.o range.o groups.o
 
@@ -29,7 +29,11 @@ obj-$(CONFIG_FREEZER) += freezer.o
 obj-$(CONFIG_PROFILING) += profile.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-y += time/
+ifneq ($(CONFIG_PREEMPT_RT_FULL),y)
+obj-y += mutex.o
 obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+obj-y += rwsem.o
+endif
 obj-$(CONFIG_LOCKDEP) += lockdep.o
 ifeq ($(CONFIG_PROC_FS),y)
 obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
@@ -41,6 +45,7 @@ endif
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
+obj-$(CONFIG_PREEMPT_RT_FULL) += rt.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
 obj-$(CONFIG_SMP) += smp.o
 ifneq ($(CONFIG_SMP),y)
Index: linux-3.4/kernel/rt.c
===================================================================
--- /dev/null
+++ linux-3.4/kernel/rt.c
@@ -0,0 +1,442 @@
+/*
+ * kernel/rt.c
+ *
+ * Real-Time Preemption Support
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * historic credit for proving that Linux spinlocks can be implemented via
+ * RT-aware mutexes goes to many people: The Pmutex project (Dirk Grambow
+ * and others) who prototyped it on 2.4 and did lots of comparative
+ * research and analysis; TimeSys, for proving that you can implement a
+ * fully preemptible kernel via the use of IRQ threading and mutexes;
+ * Bill Huey for persuasively arguing on lkml that the mutex model is the
+ * right one; and to MontaVista, who ported pmutexes to 2.6.
+ *
+ * This code is a from-scratch implementation and is not based on pmutexes,
+ * but the idea of converting spinlocks to mutexes is used here too.
+ *
+ * lock debugging, locking tree, deadlock detection:
+ *
+ *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ *  Released under the General Public License (GPL).
+ *
+ * Includes portions of the generic R/W semaphore implementation from:
+ *
+ *  Copyright (c) 2001   David Howells (dhowells@redhat.com).
+ *  - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
+ *  - Derived also from comments by Linus
+ *
+ * Pending ownership of locks and ownership stealing:
+ *
+ *  Copyright (C) 2005, Kihon Technologies Inc., Steven Rostedt
+ *
+ *   (also by Steven Rostedt)
+ *    - Converted single pi_lock to individual task locks.
+ *
+ * By Esben Nielsen:
+ *    Doing priority inheritance with help of the scheduler.
+ *
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *  - major rework based on Esben Nielsens initial patch
+ *  - replaced thread_info references by task_struct refs
+ *  - removed task->pending_owner dependency
+ *  - BKL drop/reacquire for semaphore style locks to avoid deadlocks
+ *    in the scheduler return path as discussed with Steven Rostedt
+ *
+ *  Copyright (C) 2006, Kihon Technologies Inc.
+ *    Steven Rostedt <rostedt@goodmis.org>
+ *  - debugged and patched Thomas Gleixner's rework.
+ *  - added back the cmpxchg to the rework.
+ *  - turned atomic require back on for SMP.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/rtmutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/plist.h>
+#include <linux/fs.h>
+#include <linux/futex.h>
+#include <linux/hrtimer.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * struct mutex functions
+ */
+void __mutex_do_init(struct mutex *mutex, const char *name,
+		     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
+	lockdep_init_map(&mutex->dep_map, name, key, 0);
+#endif
+	mutex->lock.save_state = 0;
+}
+EXPORT_SYMBOL(__mutex_do_init);
+
+void __lockfunc _mutex_lock(struct mutex *lock)
+{
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	rt_mutex_lock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_lock);
+
+int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	ret = rt_mutex_lock_interruptible(&lock->lock, 0);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible);
+
+int __lockfunc _mutex_lock_killable(struct mutex *lock)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	ret = rt_mutex_lock_killable(&lock->lock, 0);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass)
+{
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	rt_mutex_lock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_lock_nested);
+
+void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+	mutex_acquire_nest(&lock->dep_map, 0, 0, nest, _RET_IP_);
+	rt_mutex_lock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_lock_nest_lock);
+
+int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass)
+{
+	int ret;
+
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	ret = rt_mutex_lock_interruptible(&lock->lock, 0);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible_nested);
+
+int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	ret = rt_mutex_lock_killable(&lock->lock, 0);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable_nested);
+#endif
+
+int __lockfunc _mutex_trylock(struct mutex *lock)
+{
+	int ret = rt_mutex_trylock(&lock->lock);
+
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_trylock);
+
+void __lockfunc _mutex_unlock(struct mutex *lock)
+{
+	mutex_release(&lock->dep_map, 1, _RET_IP_);
+	rt_mutex_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_unlock);
+
+/*
+ * rwlock_t functions
+ */
+int __lockfunc rt_write_trylock(rwlock_t *rwlock)
+{
+	int ret = rt_mutex_trylock(&rwlock->lock);
+
+	migrate_disable();
+	if (ret)
+		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+	else
+		migrate_enable();
+
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+int __lockfunc rt_write_trylock_irqsave(rwlock_t *rwlock, unsigned long *flags)
+{
+	int ret;
+
+	*flags = 0;
+	migrate_disable();
+	ret = rt_write_trylock(rwlock);
+	if (!ret)
+		migrate_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock_irqsave);
+
+int __lockfunc rt_read_trylock(rwlock_t *rwlock)
+{
+	struct rt_mutex *lock = &rwlock->lock;
+	int ret = 1;
+
+	/*
+	 * recursive read locks succeed when current owns the lock,
+	 * but not when read_depth == 0 which means that the lock is
+	 * write locked.
+	 */
+	migrate_disable();
+	if (rt_mutex_owner(lock) != current)
+		ret = rt_mutex_trylock(lock);
+	else if (!rwlock->read_depth)
+		ret = 0;
+
+	if (ret) {
+		rwlock->read_depth++;
+		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
+	} else
+		migrate_enable();
+
+	return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+void __lockfunc rt_write_lock(rwlock_t *rwlock)
+{
+	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+	__rt_spin_lock(&rwlock->lock);
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+void __lockfunc rt_read_lock(rwlock_t *rwlock)
+{
+	struct rt_mutex *lock = &rwlock->lock;
+
+	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+
+	/*
+	 * recursive read locks succeed when current owns the lock
+	 */
+	if (rt_mutex_owner(lock) != current)
+		__rt_spin_lock(lock);
+	rwlock->read_depth++;
+}
+
+EXPORT_SYMBOL(rt_read_lock);
+
+void __lockfunc rt_write_unlock(rwlock_t *rwlock)
+{
+	/* NOTE: we always pass in '1' for nested, for simplicity */
+	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+	__rt_spin_unlock(&rwlock->lock);
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+void __lockfunc rt_read_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+
+	/* Release the lock only when read_depth is down to 0 */
+	if (--rwlock->read_depth == 0)
+		__rt_spin_unlock(&rwlock->lock);
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+unsigned long __lockfunc rt_write_lock_irqsave(rwlock_t *rwlock)
+{
+	rt_write_lock(rwlock);
+
+	return 0;
+}
+EXPORT_SYMBOL(rt_write_lock_irqsave);
+
+unsigned long __lockfunc rt_read_lock_irqsave(rwlock_t *rwlock)
+{
+	rt_read_lock(rwlock);
+
+	return 0;
+}
+EXPORT_SYMBOL(rt_read_lock_irqsave);
+
+void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)rwlock, sizeof(*rwlock));
+	lockdep_init_map(&rwlock->dep_map, name, key, 0);
+#endif
+	rwlock->lock.save_state = 1;
+	rwlock->read_depth = 0;
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
+
+/*
+ * rw_semaphores
+ */
+
+void  rt_up_write(struct rw_semaphore *rwsem)
+{
+	rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+	rt_mutex_unlock(&rwsem->lock);
+}
+EXPORT_SYMBOL(rt_up_write);
+
+void  rt_up_read(struct rw_semaphore *rwsem)
+{
+	rwsem_release(&rwsem->dep_map, 1, _RET_IP_);
+	if (--rwsem->read_depth == 0)
+		rt_mutex_unlock(&rwsem->lock);
+}
+EXPORT_SYMBOL(rt_up_read);
+
+/*
+ * downgrade a write lock into a read lock
+ * - just wake up any readers at the front of the queue
+ */
+void  rt_downgrade_write(struct rw_semaphore *rwsem)
+{
+	BUG_ON(rt_mutex_owner(&rwsem->lock) != current);
+	rwsem->read_depth = 1;
+}
+EXPORT_SYMBOL(rt_downgrade_write);
+
+int  rt_down_write_trylock(struct rw_semaphore *rwsem)
+{
+	int ret = rt_mutex_trylock(&rwsem->lock);
+
+	if (ret)
+		rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(rt_down_write_trylock);
+
+void  rt_down_write(struct rw_semaphore *rwsem)
+{
+	rwsem_acquire(&rwsem->dep_map, 0, 0, _RET_IP_);
+	rt_mutex_lock(&rwsem->lock);
+}
+EXPORT_SYMBOL(rt_down_write);
+
+void  rt_down_write_nested(struct rw_semaphore *rwsem, int subclass)
+{
+	rwsem_acquire(&rwsem->dep_map, subclass, 0, _RET_IP_);
+	rt_mutex_lock(&rwsem->lock);
+}
+EXPORT_SYMBOL(rt_down_write_nested);
+
+int  rt_down_read_trylock(struct rw_semaphore *rwsem)
+{
+	struct rt_mutex *lock = &rwsem->lock;
+	int ret = 1;
+
+	/*
+	 * recursive read locks succeed when current owns the rwsem,
+	 * but not when read_depth == 0 which means that the rwsem is
+	 * write locked.
+	 */
+	if (rt_mutex_owner(lock) != current)
+		ret = rt_mutex_trylock(&rwsem->lock);
+	else if (!rwsem->read_depth)
+		ret = 0;
+
+	if (ret) {
+		rwsem->read_depth++;
+		rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_down_read_trylock);
+
+static void __rt_down_read(struct rw_semaphore *rwsem, int subclass)
+{
+	struct rt_mutex *lock = &rwsem->lock;
+
+	rwsem_acquire_read(&rwsem->dep_map, subclass, 0, _RET_IP_);
+
+	if (rt_mutex_owner(lock) != current)
+		rt_mutex_lock(&rwsem->lock);
+	rwsem->read_depth++;
+}
+
+void  rt_down_read(struct rw_semaphore *rwsem)
+{
+	__rt_down_read(rwsem, 0);
+}
+EXPORT_SYMBOL(rt_down_read);
+
+void  rt_down_read_nested(struct rw_semaphore *rwsem, int subclass)
+{
+	__rt_down_read(rwsem, subclass);
+}
+EXPORT_SYMBOL(rt_down_read_nested);
+
+void  __rt_rwsem_init(struct rw_semaphore *rwsem, char *name,
+			      struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)rwsem, sizeof(*rwsem));
+	lockdep_init_map(&rwsem->dep_map, name, key, 0);
+#endif
+	rwsem->read_depth = 0;
+	rwsem->lock.save_state = 0;
+}
+EXPORT_SYMBOL(__rt_rwsem_init);
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+	/* dec if we can't possibly hit 0 */
+	if (atomic_add_unless(cnt, -1, 1))
+		return 0;
+	/* we might hit 0, so take the lock */
+	mutex_lock(lock);
+	if (!atomic_dec_and_test(cnt)) {
+		/* when we actually did the dec, we didn't hit 0 */
+		mutex_unlock(lock);
+		return 0;
+	}
+	/* we hit 0, and we hold the lock */
+	return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
Index: linux-3.4/kernel/spinlock.c
===================================================================
--- linux-3.4.orig/kernel/spinlock.c
+++ linux-3.4/kernel/spinlock.c
@@ -110,8 +110,11 @@ void __lockfunc __raw_##op##_lock_bh(loc
  *         __[spin|read|write]_lock_bh()
  */
 BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT_FULL
 BUILD_LOCK_OPS(read, rwlock);
 BUILD_LOCK_OPS(write, rwlock);
+#endif
 
 #endif
 
@@ -195,6 +198,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_
 EXPORT_SYMBOL(_raw_spin_unlock_bh);
 #endif
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+
 #ifndef CONFIG_INLINE_READ_TRYLOCK
 int __lockfunc _raw_read_trylock(rwlock_t *lock)
 {
@@ -339,6 +344,8 @@ void __lockfunc _raw_write_unlock_bh(rwl
 EXPORT_SYMBOL(_raw_write_unlock_bh);
 #endif
 
+#endif /* !PREEMPT_RT_FULL */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
Index: linux-3.4/lib/spinlock_debug.c
===================================================================
--- linux-3.4.orig/lib/spinlock_debug.c
+++ linux-3.4/lib/spinlock_debug.c
@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t
 
 EXPORT_SYMBOL(__raw_spin_lock_init);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 void __rwlock_init(rwlock_t *lock, const char *name,
 		   struct lock_class_key *key)
 {
@@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const
 }
 
 EXPORT_SYMBOL(__rwlock_init);
+#endif
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
@@ -155,6 +157,7 @@ void do_raw_spin_unlock(raw_spinlock_t *
 	arch_spin_unlock(&lock->raw_lock);
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 static void rwlock_bug(rwlock_t *lock, const char *msg)
 {
 	if (!debug_locks_off())
@@ -296,3 +299,5 @@ void do_raw_write_unlock(rwlock_t *lock)
 	debug_write_unlock(lock);
 	arch_write_unlock(&lock->raw_lock);
 }
+
+#endif
Index: linux-3.4/kernel/rcutree_plugin.h
===================================================================
--- linux-3.4.orig/kernel/rcutree_plugin.h
+++ linux-3.4/kernel/rcutree_plugin.h
@@ -339,7 +339,7 @@ static noinline void rcu_read_unlock_spe
 	}
 
 	/* Hardware IRQ handlers cannot block. */
-	if (in_irq() || in_serving_softirq()) {
+	if (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET)) {
 		local_irq_restore(flags);
 		return;
 	}
@@ -1899,7 +1899,7 @@ static void __cpuinit rcu_prepare_kthrea
 
 #endif /* #else #ifdef CONFIG_RCU_BOOST */
 
-#if !defined(CONFIG_RCU_FAST_NO_HZ)
+#if !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL)
 
 /*
  * Check to see if any future RCU-related work will need to be done
@@ -1914,6 +1914,9 @@ int rcu_needs_cpu(int cpu)
 {
 	return rcu_cpu_has_callbacks(cpu);
 }
+#endif	/* !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL) */
+
+#if !defined(CONFIG_RCU_FAST_NO_HZ)
 
 /*
  * Because we do not have RCU_FAST_NO_HZ, don't bother initializing for it.
@@ -1984,6 +1987,7 @@ static DEFINE_PER_CPU(struct hrtimer, rc
 static ktime_t rcu_idle_gp_wait;	/* If some non-lazy callbacks. */
 static ktime_t rcu_idle_lazy_gp_wait;	/* If only lazy callbacks. */
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Allow the CPU to enter dyntick-idle mode if either: (1) There are no
  * callbacks on this CPU, (2) this CPU has not yet attempted to enter
@@ -2001,6 +2005,7 @@ int rcu_needs_cpu(int cpu)
 	/* Otherwise, RCU needs the CPU only if it recently tried and failed. */
 	return per_cpu(rcu_dyntick_holdoff, cpu) == jiffies;
 }
+#endif	/* #ifndef CONFIG_PREEMPT_RT_FULL */
 
 /*
  * Does the specified flavor of RCU have non-lazy callbacks pending on
Index: linux-3.4/include/linux/rcutree.h
===================================================================
--- linux-3.4.orig/include/linux/rcutree.h
+++ linux-3.4/include/linux/rcutree.h
@@ -57,7 +57,11 @@ static inline void exit_rcu(void)
 
 #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 extern void synchronize_rcu_bh(void);
+#else
+# define synchronize_rcu_bh	synchronize_rcu
+#endif
 extern void synchronize_sched_expedited(void);
 extern void synchronize_rcu_expedited(void);
 
@@ -85,19 +89,29 @@ static inline void synchronize_rcu_bh_ex
 }
 
 extern void rcu_barrier(void);
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define rcu_barrier_bh		rcu_barrier
+#else
 extern void rcu_barrier_bh(void);
+#endif
 extern void rcu_barrier_sched(void);
 
 extern unsigned long rcutorture_testseq;
 extern unsigned long rcutorture_vernum;
 extern long rcu_batches_completed(void);
-extern long rcu_batches_completed_bh(void);
 extern long rcu_batches_completed_sched(void);
 
 extern void rcu_force_quiescent_state(void);
-extern void rcu_bh_force_quiescent_state(void);
 extern void rcu_sched_force_quiescent_state(void);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+extern void rcu_bh_force_quiescent_state(void);
+extern long rcu_batches_completed_bh(void);
+#else
+# define rcu_bh_force_quiescent_state	rcu_force_quiescent_state
+# define rcu_batches_completed_bh	rcu_batches_completed
+#endif
+
 /* A context switch is a grace period for RCU-sched and RCU-bh. */
 static inline int rcu_blocking_is_gp(void)
 {
Index: linux-3.4/kernel/rcupdate.c
===================================================================
--- linux-3.4.orig/kernel/rcupdate.c
+++ linux-3.4/kernel/rcupdate.c
@@ -77,6 +77,7 @@ int debug_lockdep_rcu_enabled(void)
 }
 EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /**
  * rcu_read_lock_bh_held() - might we be in RCU-bh read-side critical section?
  *
@@ -103,6 +104,7 @@ int rcu_read_lock_bh_held(void)
 	return in_softirq() || irqs_disabled();
 }
 EXPORT_SYMBOL_GPL(rcu_read_lock_bh_held);
+#endif
 
 #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
Index: linux-3.4/kernel/rcutree.c
===================================================================
--- linux-3.4.orig/kernel/rcutree.c
+++ linux-3.4/kernel/rcutree.c
@@ -172,6 +172,14 @@ void rcu_sched_qs(int cpu)
 	rdp->passed_quiesce = 1;
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+static void rcu_preempt_qs(int cpu);
+
+void rcu_bh_qs(int cpu)
+{
+	rcu_preempt_qs(cpu);
+}
+#else
 void rcu_bh_qs(int cpu)
 {
 	struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu);
@@ -182,6 +190,7 @@ void rcu_bh_qs(int cpu)
 		trace_rcu_grace_period("rcu_bh", rdp->gpnum, "cpuqs");
 	rdp->passed_quiesce = 1;
 }
+#endif
 
 /*
  * Note a context switch.  This is a quiescent state for RCU-sched,
@@ -228,6 +237,7 @@ long rcu_batches_completed_sched(void)
 }
 EXPORT_SYMBOL_GPL(rcu_batches_completed_sched);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Return the number of RCU BH batches processed thus far for debug & stats.
  */
@@ -245,6 +255,7 @@ void rcu_bh_force_quiescent_state(void)
 	force_quiescent_state(&rcu_bh_state, 0);
 }
 EXPORT_SYMBOL_GPL(rcu_bh_force_quiescent_state);
+#endif
 
 /*
  * Record the number of times rcutorture tests have been initiated and
@@ -1884,6 +1895,7 @@ void call_rcu_sched(struct rcu_head *hea
 }
 EXPORT_SYMBOL_GPL(call_rcu_sched);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Queue an RCU callback for invocation after a quicker grace period.
  */
@@ -1892,6 +1904,7 @@ void call_rcu_bh(struct rcu_head *head, 
 	__call_rcu(head, func, &rcu_bh_state, 0);
 }
 EXPORT_SYMBOL_GPL(call_rcu_bh);
+#endif
 
 /**
  * synchronize_sched - wait until an rcu-sched grace period has elapsed.
@@ -1928,6 +1941,7 @@ void synchronize_sched(void)
 }
 EXPORT_SYMBOL_GPL(synchronize_sched);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /**
  * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.
  *
@@ -1948,6 +1962,7 @@ void synchronize_rcu_bh(void)
 	wait_rcu_gp(call_rcu_bh);
 }
 EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
+#endif
 
 static atomic_t sync_sched_expedited_started = ATOMIC_INIT(0);
 static atomic_t sync_sched_expedited_done = ATOMIC_INIT(0);
@@ -2223,6 +2238,7 @@ static void _rcu_barrier(struct rcu_stat
 	mutex_unlock(&rcu_barrier_mutex);
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /**
  * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
  */
@@ -2231,6 +2247,7 @@ void rcu_barrier_bh(void)
 	_rcu_barrier(&rcu_bh_state, call_rcu_bh);
 }
 EXPORT_SYMBOL_GPL(rcu_barrier_bh);
+#endif
 
 /**
  * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
Index: linux-3.4/kernel/rcutiny.c
===================================================================
--- linux-3.4.orig/kernel/rcutiny.c
+++ linux-3.4/kernel/rcutiny.c
@@ -368,6 +368,7 @@ void call_rcu_sched(struct rcu_head *hea
 }
 EXPORT_SYMBOL_GPL(call_rcu_sched);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Post an RCU bottom-half callback to be invoked after any subsequent
  * quiescent state.
@@ -377,3 +378,4 @@ void call_rcu_bh(struct rcu_head *head, 
 	__call_rcu(head, func, &rcu_bh_ctrlblk);
 }
 EXPORT_SYMBOL_GPL(call_rcu_bh);
+#endif
Index: linux-3.4/include/linux/lglock.h
===================================================================
--- linux-3.4.orig/include/linux/lglock.h
+++ linux-3.4/include/linux/lglock.h
@@ -71,6 +71,8 @@
  extern void name##_global_lock_online(void);				\
  extern void name##_global_unlock_online(void);				\
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+
 #define DEFINE_LGLOCK(name)						\
 									\
  DEFINE_SPINLOCK(name##_cpu_lock);					\
@@ -197,4 +199,130 @@
 	preempt_enable();						\
  }									\
  EXPORT_SYMBOL(name##_global_unlock);
+
+#else /* !PREEMPT_RT_FULL */
+#define DEFINE_LGLOCK(name)						\
+									\
+ DEFINE_PER_CPU(struct rt_mutex, name##_lock);				\
+ DEFINE_SPINLOCK(name##_cpu_lock);					\
+ cpumask_t name##_cpus __read_mostly;					\
+ DEFINE_LGLOCK_LOCKDEP(name);						\
+									\
+ static int								\
+ name##_lg_cpu_callback(struct notifier_block *nb,			\
+				unsigned long action, void *hcpu)	\
+ {									\
+	switch (action & ~CPU_TASKS_FROZEN) {				\
+	case CPU_UP_PREPARE:						\
+		spin_lock(&name##_cpu_lock);				\
+		cpu_set((unsigned long)hcpu, name##_cpus);		\
+		spin_unlock(&name##_cpu_lock);				\
+		break;							\
+	case CPU_UP_CANCELED: case CPU_DEAD:				\
+		spin_lock(&name##_cpu_lock);				\
+		cpu_clear((unsigned long)hcpu, name##_cpus);		\
+		spin_unlock(&name##_cpu_lock);				\
+	}								\
+	return NOTIFY_OK;						\
+ }									\
+ static struct notifier_block name##_lg_cpu_notifier = {		\
+	.notifier_call = name##_lg_cpu_callback,			\
+ };									\
+ void name##_lock_init(void) {						\
+	int i;								\
+	LOCKDEP_INIT_MAP(&name##_lock_dep_map, #name, &name##_lock_key, 0); \
+	for_each_possible_cpu(i) {					\
+		struct rt_mutex *lock;					\
+		lock = &per_cpu(name##_lock, i);			\
+		rt_mutex_init(lock);					\
+	}								\
+	register_hotcpu_notifier(&name##_lg_cpu_notifier);		\
+	get_online_cpus();						\
+	for_each_online_cpu(i)						\
+		cpu_set(i, name##_cpus);				\
+	put_online_cpus();						\
+ }									\
+ EXPORT_SYMBOL(name##_lock_init);					\
+									\
+ void name##_local_lock(void) {						\
+	struct rt_mutex *lock;						\
+	migrate_disable();						\
+	rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_);	\
+	lock = &__get_cpu_var(name##_lock);				\
+	__rt_spin_lock(lock);						\
+ }									\
+ EXPORT_SYMBOL(name##_local_lock);					\
+									\
+ void name##_local_unlock(void) {					\
+	struct rt_mutex *lock;						\
+	rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_);		\
+	lock = &__get_cpu_var(name##_lock);				\
+	__rt_spin_unlock(lock);						\
+	migrate_enable();						\
+ }									\
+ EXPORT_SYMBOL(name##_local_unlock);					\
+									\
+ void name##_local_lock_cpu(int cpu) {					\
+	struct rt_mutex *lock;						\
+	rwlock_acquire_read(&name##_lock_dep_map, 0, 0, _THIS_IP_);	\
+	lock = &per_cpu(name##_lock, cpu);				\
+	__rt_spin_lock(lock);						\
+ }									\
+ EXPORT_SYMBOL(name##_local_lock_cpu);					\
+									\
+ void name##_local_unlock_cpu(int cpu) {				\
+	struct rt_mutex *lock;						\
+	rwlock_release(&name##_lock_dep_map, 1, _THIS_IP_);		\
+	lock = &per_cpu(name##_lock, cpu);				\
+	__rt_spin_unlock(lock);						\
+ }									\
+ EXPORT_SYMBOL(name##_local_unlock_cpu);				\
+									\
+ void name##_global_lock_online(void) {					\
+	int i;								\
+	rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_);		\
+	spin_lock(&name##_cpu_lock);					\
+	for_each_cpu(i, &name##_cpus) {					\
+		struct rt_mutex *lock;					\
+		lock = &per_cpu(name##_lock, i);			\
+		__rt_spin_lock(lock);					\
+	}								\
+ }									\
+ EXPORT_SYMBOL(name##_global_lock_online);				\
+									\
+ void name##_global_unlock_online(void) {				\
+	int i;								\
+	rwlock_release(&name##_lock_dep_map, 1, _RET_IP_);		\
+	for_each_cpu(i, &name##_cpus) {					\
+		struct rt_mutex *lock;					\
+		lock = &per_cpu(name##_lock, i);			\
+		__rt_spin_unlock(lock);					\
+	}								\
+	spin_unlock(&name##_cpu_lock);					\
+ }									\
+ EXPORT_SYMBOL(name##_global_unlock_online);				\
+									\
+ void name##_global_lock(void) {					\
+	int i;								\
+	rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_);		\
+	for_each_possible_cpu(i) {					\
+		struct rt_mutex *lock;					\
+		lock = &per_cpu(name##_lock, i);			\
+		__rt_spin_lock(lock);					\
+	}								\
+ }									\
+ EXPORT_SYMBOL(name##_global_lock);					\
+									\
+ void name##_global_unlock(void) {					\
+	int i;								\
+	rwlock_release(&name##_lock_dep_map, 1, _RET_IP_);		\
+	for_each_possible_cpu(i) {					\
+		struct rt_mutex *lock;					\
+		lock = &per_cpu(name##_lock, i);			\
+		__rt_spin_unlock(lock);					\
+	}								\
+ }									\
+ EXPORT_SYMBOL(name##_global_unlock);
+#endif /* PRREMPT_RT_FULL */
+
 #endif
Index: linux-3.4/drivers/tty/serial/8250/8250.c
===================================================================
--- linux-3.4.orig/drivers/tty/serial/8250/8250.c
+++ linux-3.4/drivers/tty/serial/8250/8250.c
@@ -38,6 +38,7 @@
 #include <linux/nmi.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/kdb.h>
 #ifdef CONFIG_SPARC
 #include <linux/sunserialcore.h>
 #endif
@@ -80,7 +81,16 @@ static unsigned int skip_txen_test; /* f
 #define DEBUG_INTR(fmt...)	do { } while (0)
 #endif
 
-#define PASS_LIMIT	512
+/*
+ * On -rt we can have a more delays, and legitimately
+ * so - so don't drop work spuriously and spam the
+ * syslog:
+ */
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define PASS_LIMIT	1000000
+#else
+# define PASS_LIMIT	512
+#endif
 
 #define BOTH_EMPTY 	(UART_LSR_TEMT | UART_LSR_THRE)
 
@@ -2807,14 +2817,10 @@ serial8250_console_write(struct console 
 
 	touch_nmi_watchdog();
 
-	local_irq_save(flags);
-	if (port->sysrq) {
-		/* serial8250_handle_irq() already took the lock */
-		locked = 0;
-	} else if (oops_in_progress) {
-		locked = spin_trylock(&port->lock);
-	} else
-		spin_lock(&port->lock);
+	if (port->sysrq || oops_in_progress || in_kdb_printk())
+		locked = spin_trylock_irqsave(&port->lock, flags);
+	else
+		spin_lock_irqsave(&port->lock, flags);
 
 	/*
 	 *	First save the IER then disable the interrupts
@@ -2846,8 +2852,7 @@ serial8250_console_write(struct console 
 		serial8250_modem_status(up);
 
 	if (locked)
-		spin_unlock(&port->lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&port->lock, flags);
 }
 
 static int __init serial8250_console_setup(struct console *co, char *options)
Index: linux-3.4/drivers/tty/tty_buffer.c
===================================================================
--- linux-3.4.orig/drivers/tty/tty_buffer.c
+++ linux-3.4/drivers/tty/tty_buffer.c
@@ -493,10 +493,14 @@ void tty_flip_buffer_push(struct tty_str
 		tty->buf.tail->commit = tty->buf.tail->used;
 	spin_unlock_irqrestore(&tty->buf.lock, flags);
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 	if (tty->low_latency)
 		flush_to_ldisc(&tty->buf.work);
 	else
 		schedule_work(&tty->buf.work);
+#else
+	flush_to_ldisc(&tty->buf.work);
+#endif
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
Index: linux-3.4/drivers/tty/serial/omap-serial.c
===================================================================
--- linux-3.4.orig/drivers/tty/serial/omap-serial.c
+++ linux-3.4/drivers/tty/serial/omap-serial.c
@@ -1064,13 +1064,10 @@ serial_omap_console_write(struct console
 
 	pm_runtime_get_sync(&up->pdev->dev);
 
-	local_irq_save(flags);
-	if (up->port.sysrq)
-		locked = 0;
-	else if (oops_in_progress)
-		locked = spin_trylock(&up->port.lock);
+	if (up->port.sysrq || oops_in_progress)
+		locked = spin_trylock_irqsave(&up->port.lock, flags);
 	else
-		spin_lock(&up->port.lock);
+		spin_lock_irqsave(&up->port.lock, flags);
 
 	/*
 	 * First save the IER then disable the interrupts
@@ -1099,8 +1096,7 @@ serial_omap_console_write(struct console
 	pm_runtime_mark_last_busy(&up->pdev->dev);
 	pm_runtime_put_autosuspend(&up->pdev->dev);
 	if (locked)
-		spin_unlock(&up->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
 static int __init
Index: linux-3.4/fs/namespace.c
===================================================================
--- linux-3.4.orig/fs/namespace.c
+++ linux-3.4/fs/namespace.c
@@ -20,6 +20,7 @@
 #include <linux/fs_struct.h>	/* get_fs_root et.al. */
 #include <linux/fsnotify.h>	/* fsnotify_vfsmount_delete */
 #include <linux/uaccess.h>
+#include <linux/delay.h>
 #include "pnode.h"
 #include "internal.h"
 
@@ -313,8 +314,11 @@ int mnt_want_write(struct vfsmount *m)
 	 * incremented count after it has set MNT_WRITE_HOLD.
 	 */
 	smp_mb();
-	while (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)
-		cpu_relax();
+	while (mnt->mnt.mnt_flags & MNT_WRITE_HOLD) {
+		preempt_enable();
+		cpu_chill();
+		preempt_disable();
+	}
 	/*
 	 * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
 	 * be set to match its requirements. So we must not load that until
Index: linux-3.4/fs/exec.c
===================================================================
--- linux-3.4.orig/fs/exec.c
+++ linux-3.4/fs/exec.c
@@ -840,10 +840,12 @@ static int exec_mmap(struct mm_struct *m
 		}
 	}
 	task_lock(tsk);
+	local_irq_disable_rt();
 	active_mm = tsk->active_mm;
 	tsk->mm = mm;
 	tsk->active_mm = mm;
 	activate_mm(active_mm, mm);
+	local_irq_enable_rt();
 	task_unlock(tsk);
 	arch_pick_mmap_layout(mm);
 	if (old_mm) {
Index: linux-3.4/mm/mmu_context.c
===================================================================
--- linux-3.4.orig/mm/mmu_context.c
+++ linux-3.4/mm/mmu_context.c
@@ -26,6 +26,7 @@ void use_mm(struct mm_struct *mm)
 	struct task_struct *tsk = current;
 
 	task_lock(tsk);
+	local_irq_disable_rt();
 	active_mm = tsk->active_mm;
 	if (active_mm != mm) {
 		atomic_inc(&mm->mm_count);
@@ -33,6 +34,7 @@ void use_mm(struct mm_struct *mm)
 	}
 	tsk->mm = mm;
 	switch_mm(active_mm, mm, tsk);
+	local_irq_enable_rt();
 	task_unlock(tsk);
 
 	if (active_mm != mm)
Index: linux-3.4/arch/x86/kernel/cpu/mcheck/mce.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/cpu/mcheck/mce.c
+++ linux-3.4/arch/x86/kernel/cpu/mcheck/mce.c
@@ -38,6 +38,7 @@
 #include <linux/debugfs.h>
 #include <linux/irq_work.h>
 #include <linux/export.h>
+#include <linux/jiffies.h>
 
 #include <asm/processor.h>
 #include <asm/mce.h>
@@ -1229,17 +1230,14 @@ void mce_log_therm_throt_event(__u64 sta
  * poller finds an MCE, poll 2x faster.  When the poller finds no more
  * errors, poll 2x slower (up to check_interval seconds).
  */
-static int check_interval = 5 * 60; /* 5 minutes */
+static unsigned long check_interval = 5 * 60; /* 5 minutes */
 
-static DEFINE_PER_CPU(int, mce_next_interval); /* in jiffies */
-static DEFINE_PER_CPU(struct timer_list, mce_timer);
+static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
+static DEFINE_PER_CPU(struct hrtimer, mce_timer);
 
-static void mce_start_timer(unsigned long data)
+static enum hrtimer_restart mce_start_timer(struct hrtimer *timer)
 {
-	struct timer_list *t = &per_cpu(mce_timer, data);
-	int *n;
-
-	WARN_ON(smp_processor_id() != data);
+	unsigned long *n;
 
 	if (mce_available(__this_cpu_ptr(&cpu_info))) {
 		machine_check_poll(MCP_TIMESTAMP,
@@ -1252,21 +1250,22 @@ static void mce_start_timer(unsigned lon
 	 */
 	n = &__get_cpu_var(mce_next_interval);
 	if (mce_notify_irq())
-		*n = max(*n/2, HZ/100);
+		*n = max(*n/2, HZ/100UL);
 	else
-		*n = min(*n*2, (int)round_jiffies_relative(check_interval*HZ));
+		*n = min(*n*2, round_jiffies_relative(check_interval*HZ));
 
-	t->expires = jiffies + *n;
-	add_timer_on(t, smp_processor_id());
+	hrtimer_forward(timer, timer->base->get_time(),
+			ns_to_ktime(jiffies_to_usecs(*n) * 1000));
+	return HRTIMER_RESTART;
 }
 
-/* Must not be called in IRQ context where del_timer_sync() can deadlock */
+/* Must not be called in IRQ context where hrtimer_cancel() can deadlock */
 static void mce_timer_delete_all(void)
 {
 	int cpu;
 
 	for_each_online_cpu(cpu)
-		del_timer_sync(&per_cpu(mce_timer, cpu));
+		hrtimer_cancel(&per_cpu(mce_timer, cpu));
 }
 
 static void mce_do_trigger(struct work_struct *work)
@@ -1496,10 +1495,11 @@ static void __mcheck_cpu_init_vendor(str
 
 static void __mcheck_cpu_init_timer(void)
 {
-	struct timer_list *t = &__get_cpu_var(mce_timer);
-	int *n = &__get_cpu_var(mce_next_interval);
+	struct hrtimer *t = &__get_cpu_var(mce_timer);
+	unsigned long *n = &__get_cpu_var(mce_next_interval);
 
-	setup_timer(t, mce_start_timer, smp_processor_id());
+	hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	t->function = mce_start_timer;
 
 	if (mce_ignore_ce)
 		return;
@@ -1507,8 +1507,9 @@ static void __mcheck_cpu_init_timer(void
 	*n = check_interval * HZ;
 	if (!*n)
 		return;
-	t->expires = round_jiffies(jiffies + *n);
-	add_timer_on(t, smp_processor_id());
+
+	hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(*n) * 1000),
+			       0 , HRTIMER_MODE_REL_PINNED);
 }
 
 /* Handle unconfigured int18 (should never happen) */
@@ -2160,6 +2161,8 @@ static void __cpuinit mce_disable_cpu(vo
 	if (!mce_available(__this_cpu_ptr(&cpu_info)))
 		return;
 
+	hrtimer_cancel(&__get_cpu_var(mce_timer));
+
 	if (!(action & CPU_TASKS_FROZEN))
 		cmci_clear();
 	for (i = 0; i < banks; i++) {
@@ -2186,6 +2189,7 @@ static void __cpuinit mce_reenable_cpu(v
 		if (b->init)
 			wrmsrl(MSR_IA32_MCx_CTL(i), b->ctl);
 	}
+	__mcheck_cpu_init_timer();
 }
 
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
@@ -2193,7 +2197,6 @@ static int __cpuinit
 mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 {
 	unsigned int cpu = (unsigned long)hcpu;
-	struct timer_list *t = &per_cpu(mce_timer, cpu);
 
 	switch (action) {
 	case CPU_ONLINE:
@@ -2210,16 +2213,10 @@ mce_cpu_callback(struct notifier_block *
 		break;
 	case CPU_DOWN_PREPARE:
 	case CPU_DOWN_PREPARE_FROZEN:
-		del_timer_sync(t);
 		smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
 		break;
 	case CPU_DOWN_FAILED:
 	case CPU_DOWN_FAILED_FROZEN:
-		if (!mce_ignore_ce && check_interval) {
-			t->expires = round_jiffies(jiffies +
-					   __get_cpu_var(mce_next_interval));
-			add_timer_on(t, cpu);
-		}
 		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
 		break;
 	case CPU_POST_DEAD:
Index: linux-3.4/arch/x86/include/asm/stackprotector.h
===================================================================
--- linux-3.4.orig/arch/x86/include/asm/stackprotector.h
+++ linux-3.4/arch/x86/include/asm/stackprotector.h
@@ -57,7 +57,7 @@
  */
 static __always_inline void boot_init_stack_canary(void)
 {
-	u64 canary;
+	u64 uninitialized_var(canary);
 	u64 tsc;
 
 #ifdef CONFIG_X86_64
@@ -68,8 +68,16 @@ static __always_inline void boot_init_st
 	 * of randomness. The TSC only matters for very early init,
 	 * there it already has some randomness on most systems. Later
 	 * on during the bootup the random pool has true entropy too.
+	 *
+	 * For preempt-rt we need to weaken the randomness a bit, as
+	 * we can't call into the random generator from atomic context
+	 * due to locking constraints. We just leave canary
+	 * uninitialized and use the TSC based randomness on top of
+	 * it.
 	 */
+#ifndef CONFIG_PREEMPT_RT_FULL
 	get_random_bytes(&canary, sizeof(canary));
+#endif
 	tsc = __native_read_tsc();
 	canary += tsc + (tsc << 32UL);
 
Index: linux-3.4/arch/x86/Kconfig
===================================================================
--- linux-3.4.orig/arch/x86/Kconfig
+++ linux-3.4/arch/x86/Kconfig
@@ -155,10 +155,10 @@ config ARCH_MAY_HAVE_PC_FDC
 	def_bool ISA_DMA_API
 
 config RWSEM_GENERIC_SPINLOCK
-	def_bool !X86_XADD
+	def_bool !X86_XADD || PREEMPT_RT_FULL
 
 config RWSEM_XCHGADD_ALGORITHM
-	def_bool X86_XADD
+	def_bool X86_XADD && !RWSEM_GENERIC_SPINLOCK && !PREEMPT_RT_FULL
 
 config ARCH_HAS_CPU_IDLE_WAIT
 	def_bool y
@@ -750,7 +750,7 @@ config IOMMU_HELPER
 config MAXSMP
 	bool "Enable Maximum number of SMP Processors and NUMA Nodes"
 	depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
-	select CPUMASK_OFFSTACK
+	select CPUMASK_OFFSTACK if !PREEMPT_RT_FULL
 	---help---
 	  Enable maximum number of CPUS and NUMA Nodes for this architecture.
 	  If unsure, say N.
Index: linux-3.4/arch/x86/include/asm/page_64_types.h
===================================================================
--- linux-3.4.orig/arch/x86/include/asm/page_64_types.h
+++ linux-3.4/arch/x86/include/asm/page_64_types.h
@@ -14,12 +14,21 @@
 #define IRQ_STACK_ORDER 2
 #define IRQ_STACK_SIZE (PAGE_SIZE << IRQ_STACK_ORDER)
 
-#define STACKFAULT_STACK 1
-#define DOUBLEFAULT_STACK 2
-#define NMI_STACK 3
-#define DEBUG_STACK 4
-#define MCE_STACK 5
-#define N_EXCEPTION_STACKS 5  /* hw limit: 7 */
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define STACKFAULT_STACK 0
+# define DOUBLEFAULT_STACK 1
+# define NMI_STACK 2
+# define DEBUG_STACK 0
+# define MCE_STACK 3
+# define N_EXCEPTION_STACKS 3  /* hw limit: 7 */
+#else
+# define STACKFAULT_STACK 1
+# define DOUBLEFAULT_STACK 2
+# define NMI_STACK 3
+# define DEBUG_STACK 4
+# define MCE_STACK 5
+# define N_EXCEPTION_STACKS 5  /* hw limit: 7 */
+#endif
 
 #define PUD_PAGE_SIZE		(_AC(1, UL) << PUD_SHIFT)
 #define PUD_PAGE_MASK		(~(PUD_PAGE_SIZE-1))
Index: linux-3.4/arch/x86/kernel/cpu/common.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/cpu/common.c
+++ linux-3.4/arch/x86/kernel/cpu/common.c
@@ -1056,7 +1056,9 @@ DEFINE_PER_CPU(struct task_struct *, fpu
  */
 static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
 	  [0 ... N_EXCEPTION_STACKS - 1]	= EXCEPTION_STKSZ,
+#if DEBUG_STACK > 0
 	  [DEBUG_STACK - 1]			= DEBUG_STKSZ
+#endif
 };
 
 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
Index: linux-3.4/arch/x86/kernel/dumpstack_64.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/dumpstack_64.c
+++ linux-3.4/arch/x86/kernel/dumpstack_64.c
@@ -21,10 +21,14 @@
 		(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
 
 static char x86_stack_ids[][8] = {
+#if DEBUG_STACK > 0
 		[ DEBUG_STACK-1			]	= "#DB",
+#endif
 		[ NMI_STACK-1			]	= "NMI",
 		[ DOUBLEFAULT_STACK-1		]	= "#DF",
+#if STACKFAULT_STACK > 0
 		[ STACKFAULT_STACK-1		]	= "#SS",
+#endif
 		[ MCE_STACK-1			]	= "#MC",
 #if DEBUG_STKSZ > EXCEPTION_STKSZ
 		[ N_EXCEPTION_STACKS ...
Index: linux-3.4/fs/eventpoll.c
===================================================================
--- linux-3.4.orig/fs/eventpoll.c
+++ linux-3.4/fs/eventpoll.c
@@ -488,12 +488,12 @@ static int ep_poll_wakeup_proc(void *pri
  */
 static void ep_poll_safewake(wait_queue_head_t *wq)
 {
-	int this_cpu = get_cpu();
+	int this_cpu = get_cpu_light();
 
 	ep_call_nested(&poll_safewake_ncalls, EP_MAX_NESTS,
 		       ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu);
 
-	put_cpu();
+	put_cpu_light();
 }
 
 static void ep_remove_wait_queue(struct eppoll_entry *pwq)
Index: linux-3.4/mm/vmalloc.c
===================================================================
--- linux-3.4.orig/mm/vmalloc.c
+++ linux-3.4/mm/vmalloc.c
@@ -782,7 +782,7 @@ static struct vmap_block *new_vmap_block
 	struct vmap_block *vb;
 	struct vmap_area *va;
 	unsigned long vb_idx;
-	int node, err;
+	int node, err, cpu;
 
 	node = numa_node_id();
 
@@ -821,12 +821,13 @@ static struct vmap_block *new_vmap_block
 	BUG_ON(err);
 	radix_tree_preload_end();
 
-	vbq = &get_cpu_var(vmap_block_queue);
+	cpu = get_cpu_light();
+	vbq = &__get_cpu_var(vmap_block_queue);
 	vb->vbq = vbq;
 	spin_lock(&vbq->lock);
 	list_add_rcu(&vb->free_list, &vbq->free);
 	spin_unlock(&vbq->lock);
-	put_cpu_var(vmap_block_queue);
+	put_cpu_light();
 
 	return vb;
 }
@@ -900,7 +901,7 @@ static void *vb_alloc(unsigned long size
 	struct vmap_block *vb;
 	unsigned long addr = 0;
 	unsigned int order;
-	int purge = 0;
+	int purge = 0, cpu;
 
 	BUG_ON(size & ~PAGE_MASK);
 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
@@ -908,7 +909,8 @@ static void *vb_alloc(unsigned long size
 
 again:
 	rcu_read_lock();
-	vbq = &get_cpu_var(vmap_block_queue);
+	cpu = get_cpu_light();
+	vbq = &__get_cpu_var(vmap_block_queue);
 	list_for_each_entry_rcu(vb, &vbq->free, free_list) {
 		int i;
 
@@ -945,7 +947,7 @@ next:
 	if (purge)
 		purge_fragmented_blocks_thiscpu();
 
-	put_cpu_var(vmap_block_queue);
+	put_cpu_light();
 	rcu_read_unlock();
 
 	if (!addr) {
Index: linux-3.4/include/linux/workqueue.h
===================================================================
--- linux-3.4.orig/include/linux/workqueue.h
+++ linux-3.4/include/linux/workqueue.h
@@ -254,9 +254,10 @@ enum {
 	WQ_MEM_RECLAIM		= 1 << 3, /* may be used for memory reclaim */
 	WQ_HIGHPRI		= 1 << 4, /* high priority */
 	WQ_CPU_INTENSIVE	= 1 << 5, /* cpu instensive workqueue */
+	WQ_NON_AFFINE		= 1 << 6, /* free to move works around cpus */
 
-	WQ_DRAINING		= 1 << 6, /* internal: workqueue is draining */
-	WQ_RESCUER		= 1 << 7, /* internal: workqueue has rescuer */
+	WQ_DRAINING		= 1 << 7, /* internal: workqueue is draining */
+	WQ_RESCUER		= 1 << 8, /* internal: workqueue has rescuer */
 
 	WQ_MAX_ACTIVE		= 512,	  /* I like 512, better ideas? */
 	WQ_MAX_UNBOUND_PER_CPU	= 4,	  /* 4 * #cpus for unbound wq */
Index: linux-3.4/lib/debugobjects.c
===================================================================
--- linux-3.4.orig/lib/debugobjects.c
+++ linux-3.4/lib/debugobjects.c
@@ -310,7 +310,10 @@ __debug_object_init(void *addr, struct d
 	struct debug_obj *obj;
 	unsigned long flags;
 
-	fill_pool();
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (preempt_count() == 0 && !irqs_disabled())
+#endif
+		fill_pool();
 
 	db = get_bucket((unsigned long) addr);
 
@@ -1053,9 +1056,9 @@ static int __init debug_objects_replace_
 		}
 	}
 
+	local_irq_enable();
 	printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
 	       obj_pool_used);
-	local_irq_enable();
 	return 0;
 free:
 	hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
Index: linux-3.4/include/linux/jump_label.h
===================================================================
--- linux-3.4.orig/include/linux/jump_label.h
+++ linux-3.4/include/linux/jump_label.h
@@ -51,7 +51,8 @@
 #include <linux/compiler.h>
 #include <linux/workqueue.h>
 
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
+#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) && \
+	!defined(CONFIG_PREEMPT_BASE)
 
 struct static_key {
 	atomic_t enabled;
Index: linux-3.4/include/linux/netdevice.h
===================================================================
--- linux-3.4.orig/include/linux/netdevice.h
+++ linux-3.4/include/linux/netdevice.h
@@ -1743,6 +1743,7 @@ struct softnet_data {
 	unsigned		dropped;
 	struct sk_buff_head	input_pkt_queue;
 	struct napi_struct	backlog;
+	struct sk_buff_head	tofree_queue;
 };
 
 static inline void input_queue_head_incr(struct softnet_data *sd)
Index: linux-3.4/include/linux/skbuff.h
===================================================================
--- linux-3.4.orig/include/linux/skbuff.h
+++ linux-3.4/include/linux/skbuff.h
@@ -132,6 +132,7 @@ struct sk_buff_head {
 
 	__u32		qlen;
 	spinlock_t	lock;
+	raw_spinlock_t	raw_lock;
 };
 
 struct sk_buff;
@@ -967,6 +968,12 @@ static inline void skb_queue_head_init(s
 	__skb_queue_head_init(list);
 }
 
+static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
+{
+	raw_spin_lock_init(&list->raw_lock);
+	__skb_queue_head_init(list);
+}
+
 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
 		struct lock_class_key *class)
 {
Index: linux-3.4/arch/x86/kernel/irq_work.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/irq_work.c
+++ linux-3.4/arch/x86/kernel/irq_work.c
@@ -18,6 +18,7 @@ void smp_irq_work_interrupt(struct pt_re
 	irq_exit();
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 void arch_irq_work_raise(void)
 {
 #ifdef CONFIG_X86_LOCAL_APIC
@@ -28,3 +29,4 @@ void arch_irq_work_raise(void)
 	apic_wait_icr_idle();
 #endif
 }
+#endif
Index: linux-3.4/kernel/irq_work.c
===================================================================
--- linux-3.4.orig/kernel/irq_work.c
+++ linux-3.4/kernel/irq_work.c
@@ -107,8 +107,10 @@ void irq_work_run(void)
 	if (llist_empty(this_list))
 		return;
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 	BUG_ON(!in_irq());
 	BUG_ON(!irqs_disabled());
+#endif
 
 	llnode = llist_del_all(this_list);
 	while (llnode != NULL) {
Index: linux-3.4/arch/powerpc/Kconfig
===================================================================
--- linux-3.4.orig/arch/powerpc/Kconfig
+++ linux-3.4/arch/powerpc/Kconfig
@@ -69,10 +69,11 @@ config LOCKDEP_SUPPORT
 
 config RWSEM_GENERIC_SPINLOCK
 	bool
+	default y if PREEMPT_RT_FULL
 
 config RWSEM_XCHGADD_ALGORITHM
 	bool
-	default y
+	default y if !PREEMPT_RT_FULL
 
 config GENERIC_LOCKBREAK
 	bool
@@ -282,7 +283,7 @@ menu "Kernel options"
 
 config HIGHMEM
 	bool "High memory support"
-	depends on PPC32
+	depends on PPC32 && !PREEMPT_RT_FULL
 
 source kernel/time/Kconfig
 source kernel/Kconfig.hz
Index: linux-3.4/arch/mips/Kconfig
===================================================================
--- linux-3.4.orig/arch/mips/Kconfig
+++ linux-3.4/arch/mips/Kconfig
@@ -2081,7 +2081,7 @@ config CPU_R4400_WORKAROUNDS
 #
 config HIGHMEM
 	bool "High Memory Support"
-	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM
+	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !PREEMPT_RT_FULL
 
 config CPU_SUPPORTS_HIGHMEM
 	bool
Index: linux-3.4/Documentation/sysrq.txt
===================================================================
--- linux-3.4.orig/Documentation/sysrq.txt
+++ linux-3.4/Documentation/sysrq.txt
@@ -57,10 +57,17 @@ On PowerPC - Press 'ALT - Print Screen (
 On other - If you know of the key combos for other architectures, please
            let me know so I can add them to this section.
 
-On all -  write a character to /proc/sysrq-trigger.  e.g.:
-
+On all -  write a character to /proc/sysrq-trigger, e.g.:
 		echo t > /proc/sysrq-trigger
 
+On all - Enable network SysRq by writing a cookie to icmp_echo_sysrq, e.g.
+		echo 0x01020304 >/proc/sys/net/ipv4/icmp_echo_sysrq
+	 Send an ICMP echo request with this pattern plus the particular
+	 SysRq command key. Example:
+	 	# ping -c1 -s57 -p0102030468
+	 will trigger the SysRq-H (help) command.
+
+
 *  What are the 'command' keys?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 'b'     - Will immediately reboot the system without syncing or unmounting
Index: linux-3.4/include/net/netns/ipv4.h
===================================================================
--- linux-3.4.orig/include/net/netns/ipv4.h
+++ linux-3.4/include/net/netns/ipv4.h
@@ -47,6 +47,7 @@ struct netns_ipv4 {
 
 	int sysctl_icmp_echo_ignore_all;
 	int sysctl_icmp_echo_ignore_broadcasts;
+	int sysctl_icmp_echo_sysrq;
 	int sysctl_icmp_ignore_bogus_error_responses;
 	int sysctl_icmp_ratelimit;
 	int sysctl_icmp_ratemask;
Index: linux-3.4/net/ipv4/icmp.c
===================================================================
--- linux-3.4.orig/net/ipv4/icmp.c
+++ linux-3.4/net/ipv4/icmp.c
@@ -69,6 +69,7 @@
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/fcntl.h>
+#include <linux/sysrq.h>
 #include <linux/socket.h>
 #include <linux/in.h>
 #include <linux/inet.h>
@@ -799,6 +800,30 @@ out_err:
 }
 
 /*
+ * 32bit and 64bit have different timestamp length, so we check for
+ * the cookie at offset 20 and verify it is repeated at offset 50
+ */
+#define CO_POS0		20
+#define CO_POS1		50
+#define CO_SIZE		sizeof(int)
+#define ICMP_SYSRQ_SIZE	57
+
+/*
+ * We got a ICMP_SYSRQ_SIZE sized ping request. Check for the cookie
+ * pattern and if it matches send the next byte as a trigger to sysrq.
+ */
+static void icmp_check_sysrq(struct net *net, struct sk_buff *skb)
+{
+	int cookie = htonl(net->ipv4.sysctl_icmp_echo_sysrq);
+	char *p = skb->data;
+
+	if (!memcmp(&cookie, p + CO_POS0, CO_SIZE) &&
+	    !memcmp(&cookie, p + CO_POS1, CO_SIZE) &&
+	    p[CO_POS0 + CO_SIZE] == p[CO_POS1 + CO_SIZE])
+		handle_sysrq(p[CO_POS0 + CO_SIZE]);
+}
+
+/*
  *	Handle ICMP_ECHO ("ping") requests.
  *
  *	RFC 1122: 3.2.2.6 MUST have an echo server that answers ICMP echo
@@ -825,6 +850,11 @@ static void icmp_echo(struct sk_buff *sk
 		icmp_param.data_len	   = skb->len;
 		icmp_param.head_len	   = sizeof(struct icmphdr);
 		icmp_reply(&icmp_param, skb);
+
+		if (skb->len == ICMP_SYSRQ_SIZE &&
+		    net->ipv4.sysctl_icmp_echo_sysrq) {
+			icmp_check_sysrq(net, skb);
+		}
 	}
 }
 
Index: linux-3.4/net/ipv4/sysctl_net_ipv4.c
===================================================================
--- linux-3.4.orig/net/ipv4/sysctl_net_ipv4.c
+++ linux-3.4/net/ipv4/sysctl_net_ipv4.c
@@ -718,6 +718,13 @@ static struct ctl_table ipv4_net_table[]
 		.proc_handler	= proc_dointvec
 	},
 	{
+		.procname	= "icmp_echo_sysrq",
+		.data		= &init_net.ipv4.sysctl_icmp_echo_sysrq,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec
+	},
+	{
 		.procname	= "icmp_ignore_bogus_error_responses",
 		.data		= &init_net.ipv4.sysctl_icmp_ignore_bogus_error_responses,
 		.maxlen		= sizeof(int),
Index: linux-3.4/include/linux/kdb.h
===================================================================
--- linux-3.4.orig/include/linux/kdb.h
+++ linux-3.4/include/linux/kdb.h
@@ -150,12 +150,14 @@ extern int kdb_register(char *, kdb_func
 extern int kdb_register_repeat(char *, kdb_func_t, char *, char *,
 			       short, kdb_repeat_t);
 extern int kdb_unregister(char *);
+#define in_kdb_printk() (kdb_trap_printk)
 #else /* ! CONFIG_KGDB_KDB */
 #define kdb_printf(...)
 #define kdb_init(x)
 #define kdb_register(...)
 #define kdb_register_repeat(...)
 #define kdb_uregister(x)
+#define in_kdb_printk() (0)
 #endif	/* CONFIG_KGDB_KDB */
 enum {
 	KDB_NOT_INITIALIZED,
Index: linux-3.4/kernel/debug/kdb/kdb_io.c
===================================================================
--- linux-3.4.orig/kernel/debug/kdb/kdb_io.c
+++ linux-3.4/kernel/debug/kdb/kdb_io.c
@@ -553,7 +553,6 @@ int vkdb_printf(const char *fmt, va_list
 	int diag;
 	int linecount;
 	int logging, saved_loglevel = 0;
-	int saved_trap_printk;
 	int got_printf_lock = 0;
 	int retlen = 0;
 	int fnd, len;
@@ -564,8 +563,6 @@ int vkdb_printf(const char *fmt, va_list
 	unsigned long uninitialized_var(flags);
 
 	preempt_disable();
-	saved_trap_printk = kdb_trap_printk;
-	kdb_trap_printk = 0;
 
 	/* Serialize kdb_printf if multiple cpus try to write at once.
 	 * But if any cpu goes recursive in kdb, just print the output,
@@ -821,7 +818,6 @@ kdb_print_out:
 	} else {
 		__release(kdb_printf_lock);
 	}
-	kdb_trap_printk = saved_trap_printk;
 	preempt_enable();
 	return retlen;
 }
@@ -831,9 +827,11 @@ int kdb_printf(const char *fmt, ...)
 	va_list ap;
 	int r;
 
+	kdb_trap_printk++;
 	va_start(ap, fmt);
 	r = vkdb_printf(fmt, ap);
 	va_end(ap);
+	kdb_trap_printk--;
 
 	return r;
 }
Index: linux-3.4/kernel/ksysfs.c
===================================================================
--- linux-3.4.orig/kernel/ksysfs.c
+++ linux-3.4/kernel/ksysfs.c
@@ -133,6 +133,15 @@ KERNEL_ATTR_RO(vmcoreinfo);
 
 #endif /* CONFIG_KEXEC */
 
+#if defined(CONFIG_PREEMPT_RT_FULL)
+static ssize_t  realtime_show(struct kobject *kobj,
+			      struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", 1);
+}
+KERNEL_ATTR_RO(realtime);
+#endif
+
 /* whether file capabilities are enabled */
 static ssize_t fscaps_show(struct kobject *kobj,
 				  struct kobj_attribute *attr, char *buf)
@@ -182,6 +191,9 @@ static struct attribute * kernel_attrs[]
 	&kexec_crash_size_attr.attr,
 	&vmcoreinfo_attr.attr,
 #endif
+#ifdef CONFIG_PREEMPT_RT_FULL
+	&realtime_attr.attr,
+#endif
 	NULL
 };
 
Index: linux-3.4/arch/x86/kernel/process_32.c
===================================================================
--- linux-3.4.orig/arch/x86/kernel/process_32.c
+++ linux-3.4/arch/x86/kernel/process_32.c
@@ -36,6 +36,7 @@
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
+#include <linux/highmem.h>
 
 #include <asm/pgtable.h>
 #include <asm/ldt.h>
@@ -285,6 +286,41 @@ __switch_to(struct task_struct *prev_p, 
 		     task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT))
 		__switch_to_xtra(prev_p, next_p, tss);
 
+#if defined CONFIG_PREEMPT_RT_FULL && defined CONFIG_HIGHMEM
+	/*
+	 * Save @prev's kmap_atomic stack
+	 */
+	prev_p->kmap_idx = __this_cpu_read(__kmap_atomic_idx);
+	if (unlikely(prev_p->kmap_idx)) {
+		int i;
+
+		for (i = 0; i < prev_p->kmap_idx; i++) {
+			int idx = i + KM_TYPE_NR * smp_processor_id();
+
+			pte_t *ptep = kmap_pte - idx;
+			prev_p->kmap_pte[i] = *ptep;
+			kpte_clear_flush(ptep, __fix_to_virt(FIX_KMAP_BEGIN + idx));
+		}
+
+		__this_cpu_write(__kmap_atomic_idx, 0);
+	}
+
+	/*
+	 * Restore @next_p's kmap_atomic stack
+	 */
+	if (unlikely(next_p->kmap_idx)) {
+		int i;
+
+		__this_cpu_write(__kmap_atomic_idx, next_p->kmap_idx);
+
+		for (i = 0; i < next_p->kmap_idx; i++) {
+			int idx = i + KM_TYPE_NR * smp_processor_id();
+
+			set_pte(kmap_pte - idx, next_p->kmap_pte[i]);
+		}
+	}
+#endif
+
 	/*
 	 * Leave lazy mode, flushing any hypercalls made here.
 	 * This must be done before restoring TLS segments so
Index: linux-3.4/ipc/sem.c
===================================================================
--- linux-3.4.orig/ipc/sem.c
+++ linux-3.4/ipc/sem.c
@@ -461,6 +461,13 @@ undo:
 static void wake_up_sem_queue_prepare(struct list_head *pt,
 				struct sem_queue *q, int error)
 {
+#ifdef CONFIG_PREEMPT_RT_BASE
+	struct task_struct *p = q->sleeper;
+	get_task_struct(p);
+	q->status = error;
+	wake_up_process(p);
+	put_task_struct(p);
+#else
 	if (list_empty(pt)) {
 		/*
 		 * Hold preempt off so that we don't get preempted and have the
@@ -472,6 +479,7 @@ static void wake_up_sem_queue_prepare(st
 	q->pid = error;
 
 	list_add_tail(&q->simple_list, pt);
+#endif
 }
 
 /**
@@ -485,6 +493,7 @@ static void wake_up_sem_queue_prepare(st
  */
 static void wake_up_sem_queue_do(struct list_head *pt)
 {
+#ifndef CONFIG_PREEMPT_RT_BASE
 	struct sem_queue *q, *t;
 	int did_something;
 
@@ -497,6 +506,7 @@ static void wake_up_sem_queue_do(struct 
 	}
 	if (did_something)
 		preempt_enable();
+#endif
 }
 
 static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
Index: linux-3.4/drivers/tty/serial/cpm_uart/cpm_uart_core.c
===================================================================
--- linux-3.4.orig/drivers/tty/serial/cpm_uart/cpm_uart_core.c
+++ linux-3.4/drivers/tty/serial/cpm_uart/cpm_uart_core.c
@@ -1226,7 +1226,7 @@ static void cpm_uart_console_write(struc
 {
 	struct uart_cpm_port *pinfo = &cpm_uart_ports[co->index];
 	unsigned long flags;
-	int nolock = oops_in_progress;
+	int nolock = oops_in_progress || sysrq_in_progress;
 
 	if (unlikely(nolock)) {
 		local_irq_save(flags);
Index: linux-3.4/drivers/tty/sysrq.c
===================================================================
--- linux-3.4.orig/drivers/tty/sysrq.c
+++ linux-3.4/drivers/tty/sysrq.c
@@ -495,6 +495,23 @@ static void __sysrq_put_key_op(int key, 
                 sysrq_key_table[i] = op_p;
 }
 
+#ifdef CONFIG_MAGIC_SYSRQ_FORCE_PRINTK
+
+int sysrq_in_progress;
+
+static void set_sysrq_in_progress(int value)
+{
+	sysrq_in_progress = value;
+}
+
+#else
+
+static void set_sysrq_in_progress(int value)
+{
+}
+
+#endif
+
 void __handle_sysrq(int key, bool check_mask)
 {
 	struct sysrq_key_op *op_p;
@@ -503,6 +520,9 @@ void __handle_sysrq(int key, bool check_
 	unsigned long flags;
 
 	spin_lock_irqsave(&sysrq_key_table_lock, flags);
+
+	set_sysrq_in_progress(1);
+
 	/*
 	 * Raise the apparent loglevel to maximum so that the sysrq header
 	 * is shown to provide the user with positive feedback.  We do not
@@ -544,6 +564,9 @@ void __handle_sysrq(int key, bool check_
 		printk("\n");
 		console_loglevel = orig_log_level;
 	}
+
+	set_sysrq_in_progress(0);
+
 	spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
 }
 
Index: linux-3.4/include/linux/sysrq.h
===================================================================
--- linux-3.4.orig/include/linux/sysrq.h
+++ linux-3.4/include/linux/sysrq.h
@@ -38,6 +38,11 @@ struct sysrq_key_op {
 	int enable_mask;
 };
 
+#ifdef CONFIG_MAGIC_SYSRQ_FORCE_PRINTK
+extern int sysrq_in_progress;
+#else
+#define sysrq_in_progress 0
+#endif
 #ifdef CONFIG_MAGIC_SYSRQ
 
 /* Generic SysRq interface -- you may call it from any device driver, supplying
Index: linux-3.4/arch/x86/kvm/x86.c
===================================================================
--- linux-3.4.orig/arch/x86/kvm/x86.c
+++ linux-3.4/arch/x86/kvm/x86.c
@@ -4882,6 +4882,13 @@ int kvm_arch_init(void *opaque)
 		goto out;
 	}
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
+		printk(KERN_ERR "RT requires X86_FEATURE_CONSTANT_TSC\n");
+		return -EOPNOTSUPP;
+	}
+#endif
+
 	r = kvm_mmu_module_init();
 	if (r)
 		goto out;
Index: linux-3.4/drivers/scsi/fcoe/fcoe.c
===================================================================
--- linux-3.4.orig/drivers/scsi/fcoe/fcoe.c
+++ linux-3.4/drivers/scsi/fcoe/fcoe.c
@@ -1222,7 +1222,7 @@ static void fcoe_percpu_thread_destroy(u
 	struct sk_buff *skb;
 #ifdef CONFIG_SMP
 	struct fcoe_percpu_s *p0;
-	unsigned targ_cpu = get_cpu();
+	unsigned targ_cpu = get_cpu_light();
 #endif /* CONFIG_SMP */
 
 	FCOE_DBG("Destroying receive thread for CPU %d\n", cpu);
@@ -1278,7 +1278,7 @@ static void fcoe_percpu_thread_destroy(u
 			kfree_skb(skb);
 		spin_unlock_bh(&p->fcoe_rx_list.lock);
 	}
-	put_cpu();
+	put_cpu_light();
 #else
 	/*
 	 * This a non-SMP scenario where the singular Rx thread is
@@ -1494,11 +1494,11 @@ err2:
 static int fcoe_alloc_paged_crc_eof(struct sk_buff *skb, int tlen)
 {
 	struct fcoe_percpu_s *fps;
-	int rc;
+	int rc, cpu = get_cpu_light();
 
-	fps = &get_cpu_var(fcoe_percpu);
+	fps = &per_cpu(fcoe_percpu, cpu);
 	rc = fcoe_get_paged_crc_eof(skb, tlen, fps);
-	put_cpu_var(fcoe_percpu);
+	put_cpu_light();
 
 	return rc;
 }
@@ -1738,7 +1738,7 @@ static void fcoe_recv_frame(struct sk_bu
 	 */
 	hp = (struct fcoe_hdr *) skb_network_header(skb);
 
-	stats = per_cpu_ptr(lport->dev_stats, get_cpu());
+	stats = per_cpu_ptr(lport->dev_stats, get_cpu_light());
 	if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
 		if (stats->ErrorFrames < 5)
 			printk(KERN_WARNING "fcoe: FCoE version "
@@ -1770,13 +1770,13 @@ static void fcoe_recv_frame(struct sk_bu
 		goto drop;
 
 	if (!fcoe_filter_frames(lport, fp)) {
-		put_cpu();
+		put_cpu_light();
 		fc_exch_recv(lport, fp);
 		return;
 	}
 drop:
 	stats->ErrorFrames++;
-	put_cpu();
+	put_cpu_light();
 	kfree_skb(skb);
 }
 
Index: linux-3.4/drivers/scsi/fcoe/fcoe_ctlr.c
===================================================================
--- linux-3.4.orig/drivers/scsi/fcoe/fcoe_ctlr.c
+++ linux-3.4/drivers/scsi/fcoe/fcoe_ctlr.c
@@ -719,7 +719,7 @@ static unsigned long fcoe_ctlr_age_fcfs(
 	unsigned long sel_time = 0;
 	struct fcoe_dev_stats *stats;
 
-	stats = per_cpu_ptr(fip->lp->dev_stats, get_cpu());
+	stats = per_cpu_ptr(fip->lp->dev_stats, get_cpu_light());
 
 	list_for_each_entry_safe(fcf, next, &fip->fcfs, list) {
 		deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2;
@@ -752,7 +752,7 @@ static unsigned long fcoe_ctlr_age_fcfs(
 				sel_time = fcf->time;
 		}
 	}
-	put_cpu();
+	put_cpu_light();
 	if (sel_time && !fip->sel_fcf && !fip->sel_time) {
 		sel_time += msecs_to_jiffies(FCOE_CTLR_START_DELAY);
 		fip->sel_time = sel_time;
Index: linux-3.4/drivers/scsi/libfc/fc_exch.c
===================================================================
--- linux-3.4.orig/drivers/scsi/libfc/fc_exch.c
+++ linux-3.4/drivers/scsi/libfc/fc_exch.c
@@ -724,10 +724,10 @@ static struct fc_exch *fc_exch_em_alloc(
 	}
 	memset(ep, 0, sizeof(*ep));
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	pool = per_cpu_ptr(mp->pool, cpu);
 	spin_lock_bh(&pool->lock);
-	put_cpu();
+	put_cpu_light();
 
 	/* peek cache of free slot */
 	if (pool->left != FC_XID_UNKNOWN) {
Index: linux-3.4/arch/x86/crypto/aesni-intel_glue.c
===================================================================
--- linux-3.4.orig/arch/x86/crypto/aesni-intel_glue.c
+++ linux-3.4/arch/x86/crypto/aesni-intel_glue.c
@@ -290,14 +290,14 @@ static int ecb_encrypt(struct blkcipher_
 	err = blkcipher_walk_virt(desc, &walk);
 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_ecb_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
-			      nbytes & AES_BLOCK_MASK);
+				nbytes & AES_BLOCK_MASK);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = blkcipher_walk_done(desc, &walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -314,14 +314,14 @@ static int ecb_decrypt(struct blkcipher_
 	err = blkcipher_walk_virt(desc, &walk);
 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_ecb_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = blkcipher_walk_done(desc, &walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -360,14 +360,14 @@ static int cbc_encrypt(struct blkcipher_
 	err = blkcipher_walk_virt(desc, &walk);
 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = blkcipher_walk_done(desc, &walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -384,14 +384,14 @@ static int cbc_decrypt(struct blkcipher_
 	err = blkcipher_walk_virt(desc, &walk);
 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = blkcipher_walk_done(desc, &walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -446,18 +446,20 @@ static int ctr_crypt(struct blkcipher_de
 	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
 	desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
+		kernel_fpu_begin();
 		aesni_ctr_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = blkcipher_walk_done(desc, &walk, nbytes);
 	}
 	if (walk.nbytes) {
+		kernel_fpu_begin();
 		ctr_crypt_final(ctx, &walk);
+		kernel_fpu_end();
 		err = blkcipher_walk_done(desc, &walk, 0);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
Index: linux-3.4/drivers/md/dm.c
===================================================================
--- linux-3.4.orig/drivers/md/dm.c
+++ linux-3.4/drivers/md/dm.c
@@ -1648,14 +1648,14 @@ static void dm_request_fn(struct request
 		if (map_request(ti, clone, md))
 			goto requeued;
 
-		BUG_ON(!irqs_disabled());
+		BUG_ON_NONRT(!irqs_disabled());
 		spin_lock(q->queue_lock);
 	}
 
 	goto out;
 
 requeued:
-	BUG_ON(!irqs_disabled());
+	BUG_ON_NONRT(!irqs_disabled());
 	spin_lock(q->queue_lock);
 
 delay_and_out:
Index: linux-3.4/lib/Kconfig
===================================================================
--- linux-3.4.orig/lib/Kconfig
+++ linux-3.4/lib/Kconfig
@@ -303,6 +303,7 @@ config CHECK_SIGNATURE
 
 config CPUMASK_OFFSTACK
 	bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS
+	depends on !PREEMPT_RT_FULL
 	help
 	  Use dynamic allocation for cpumask_var_t, instead of putting
 	  them on the stack.  This is a bit more expensive, but avoids
Index: linux-3.4/include/net/neighbour.h
===================================================================
--- linux-3.4.orig/include/net/neighbour.h
+++ linux-3.4/include/net/neighbour.h
@@ -394,7 +394,7 @@ struct neighbour_cb {
 
 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
 
-static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
+static inline void neigh_ha_snapshot(char *dst, struct neighbour *n,
 				     const struct net_device *dev)
 {
 	unsigned int seq;
Index: linux-3.4/block/blk-iopoll.c
===================================================================
--- linux-3.4.orig/block/blk-iopoll.c
+++ linux-3.4/block/blk-iopoll.c
@@ -38,6 +38,7 @@ void blk_iopoll_sched(struct blk_iopoll 
 	list_add_tail(&iop->list, &__get_cpu_var(blk_cpu_iopoll));
 	__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(blk_iopoll_sched);
 
@@ -135,6 +136,7 @@ static void blk_iopoll_softirq(struct so
 		__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
 
 	local_irq_enable();
+	preempt_check_resched_rt();
 }
 
 /**
@@ -204,6 +206,7 @@ static int __cpuinit blk_iopoll_cpu_noti
 				 &__get_cpu_var(blk_cpu_iopoll));
 		__raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
 		local_irq_enable();
+		preempt_check_resched_rt();
 	}
 
 	return NOTIFY_OK;
Index: linux-3.4/block/blk-softirq.c
===================================================================
--- linux-3.4.orig/block/blk-softirq.c
+++ linux-3.4/block/blk-softirq.c
@@ -51,6 +51,7 @@ static void trigger_softirq(void *data)
 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
 
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 
 /*
@@ -93,6 +94,7 @@ static int __cpuinit blk_cpu_notify(stru
 				 &__get_cpu_var(blk_cpu_done));
 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
 		local_irq_enable();
+		preempt_check_resched_rt();
 	}
 
 	return NOTIFY_OK;
@@ -150,6 +152,7 @@ do_local:
 		goto do_local;
 
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 
 /**
Index: linux-3.4/include/linux/delay.h
===================================================================
--- linux-3.4.orig/include/linux/delay.h
+++ linux-3.4/include/linux/delay.h
@@ -52,4 +52,10 @@ static inline void ssleep(unsigned int s
 	msleep(seconds * 1000);
 }
 
+#ifdef CONFIG_PREEMPT_RT_FULL
+# define cpu_chill()	msleep(1)
+#else
+# define cpu_chill()	cpu_relax()
+#endif
+
 #endif /* defined(_LINUX_DELAY_H) */
Index: linux-3.4/fs/autofs4/autofs_i.h
===================================================================
--- linux-3.4.orig/fs/autofs4/autofs_i.h
+++ linux-3.4/fs/autofs4/autofs_i.h
@@ -34,6 +34,7 @@
 #include <linux/sched.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
+#include <linux/delay.h>
 #include <asm/current.h>
 #include <asm/uaccess.h>
 
Index: linux-3.4/fs/autofs4/expire.c
===================================================================
--- linux-3.4.orig/fs/autofs4/expire.c
+++ linux-3.4/fs/autofs4/expire.c
@@ -171,7 +171,7 @@ again:
 			parent = p->d_parent;
 			if (!spin_trylock(&parent->d_lock)) {
 				spin_unlock(&p->d_lock);
-				cpu_relax();
+				cpu_chill();
 				goto relock;
 			}
 			spin_unlock(&p->d_lock);
Index: linux-3.4/fs/dcache.c
===================================================================
--- linux-3.4.orig/fs/dcache.c
+++ linux-3.4/fs/dcache.c
@@ -37,6 +37,7 @@
 #include <linux/rculist_bl.h>
 #include <linux/prefetch.h>
 #include <linux/ratelimit.h>
+#include <linux/delay.h>
 #include "internal.h"
 #include "mount.h"
 
@@ -454,7 +455,7 @@ static inline struct dentry *dentry_kill
 	if (inode && !spin_trylock(&inode->i_lock)) {
 relock:
 		spin_unlock(&dentry->d_lock);
-		cpu_relax();
+		cpu_chill();
 		return dentry; /* try again with same dentry */
 	}
 	if (IS_ROOT(dentry))
@@ -840,7 +841,7 @@ relock:
 
 		if (!spin_trylock(&dentry->d_lock)) {
 			spin_unlock(&dcache_lru_lock);
-			cpu_relax();
+			cpu_chill();
 			goto relock;
 		}
 
@@ -2022,7 +2023,7 @@ again:
 	if (dentry->d_count == 1) {
 		if (inode && !spin_trylock(&inode->i_lock)) {
 			spin_unlock(&dentry->d_lock);
-			cpu_relax();
+			cpu_chill();
 			goto again;
 		}
 		dentry->d_flags &= ~DCACHE_CANT_MOUNT;
Index: linux-3.4/net/packet/af_packet.c
===================================================================
--- linux-3.4.orig/net/packet/af_packet.c
+++ linux-3.4/net/packet/af_packet.c
@@ -88,6 +88,7 @@
 #include <linux/virtio_net.h>
 #include <linux/errqueue.h>
 #include <linux/net_tstamp.h>
+#include <linux/delay.h>
 
 #ifdef CONFIG_INET
 #include <net/inet_common.h>
@@ -672,7 +673,7 @@ static void prb_retire_rx_blk_timer_expi
 	if (BLOCK_NUM_PKTS(pbd)) {
 		while (atomic_read(&pkc->blk_fill_in_prog)) {
 			/* Waiting for skb_copy_bits to finish... */
-			cpu_relax();
+			cpu_chill();
 		}
 	}
 
@@ -927,7 +928,7 @@ static void prb_retire_current_block(str
 		if (!(status & TP_STATUS_BLK_TMO)) {
 			while (atomic_read(&pkc->blk_fill_in_prog)) {
 				/* Waiting for skb_copy_bits to finish... */
-				cpu_relax();
+				cpu_chill();
 			}
 		}
 		prb_close_block(pkc, pbd, po, status);
Index: linux-3.4/net/rds/ib_rdma.c
===================================================================
--- linux-3.4.orig/net/rds/ib_rdma.c
+++ linux-3.4/net/rds/ib_rdma.c
@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/rculist.h>
 #include <linux/llist.h>
+#include <linux/delay.h>
 
 #include "rds.h"
 #include "ib.h"
@@ -286,7 +287,7 @@ static inline void wait_clean_list_grace
 	for_each_online_cpu(cpu) {
 		flag = &per_cpu(clean_list_grace, cpu);
 		while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
-			cpu_relax();
+			cpu_chill();
 	}
 }
 
Index: linux-3.4/kernel/time/ntp.c
===================================================================
--- linux-3.4.orig/kernel/time/ntp.c
+++ linux-3.4/kernel/time/ntp.c
@@ -22,7 +22,7 @@
  * NTP timekeeping variables:
  */
 
-DEFINE_SPINLOCK(ntp_lock);
+DEFINE_RAW_SPINLOCK(ntp_lock);
 
 
 /* USER_HZ period (usecs): */
@@ -347,7 +347,7 @@ void ntp_clear(void)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&ntp_lock, flags);
+	raw_spin_lock_irqsave(&ntp_lock, flags);
 
 	time_adjust	= 0;		/* stop active adjtime() */
 	time_status	|= STA_UNSYNC;
@@ -361,7 +361,7 @@ void ntp_clear(void)
 
 	/* Clear PPS state variables */
 	pps_clear();
-	spin_unlock_irqrestore(&ntp_lock, flags);
+	raw_spin_unlock_irqrestore(&ntp_lock, flags);
 
 }
 
@@ -371,9 +371,9 @@ u64 ntp_tick_length(void)
 	unsigned long flags;
 	s64 ret;
 
-	spin_lock_irqsave(&ntp_lock, flags);
+	raw_spin_lock_irqsave(&ntp_lock, flags);
 	ret = tick_length;
-	spin_unlock_irqrestore(&ntp_lock, flags);
+	raw_spin_unlock_irqrestore(&ntp_lock, flags);
 	return ret;
 }
 
@@ -394,7 +394,7 @@ int second_overflow(unsigned long secs)
 	int leap = 0;
 	unsigned long flags;
 
-	spin_lock_irqsave(&ntp_lock, flags);
+	raw_spin_lock_irqsave(&ntp_lock, flags);
 
 	/*
 	 * Leap second processing. If in leap-insert state at the end of the
@@ -476,7 +476,7 @@ int second_overflow(unsigned long secs)
 
 
 out:
-	spin_unlock_irqrestore(&ntp_lock, flags);
+	raw_spin_unlock_irqrestore(&ntp_lock, flags);
 
 	return leap;
 }
@@ -658,7 +658,7 @@ int do_adjtimex(struct timex *txc)
 
 	getnstimeofday(&ts);
 
-	spin_lock_irq(&ntp_lock);
+	raw_spin_lock_irq(&ntp_lock);
 
 	if (txc->modes & ADJ_ADJTIME) {
 		long save_adjust = time_adjust;
@@ -700,7 +700,7 @@ int do_adjtimex(struct timex *txc)
 	/* fill PPS status fields */
 	pps_fill_timex(txc);
 
-	spin_unlock_irq(&ntp_lock);
+	raw_spin_unlock_irq(&ntp_lock);
 
 	txc->time.tv_sec = ts.tv_sec;
 	txc->time.tv_usec = ts.tv_nsec;
@@ -898,7 +898,7 @@ void hardpps(const struct timespec *phas
 
 	pts_norm = pps_normalize_ts(*phase_ts);
 
-	spin_lock_irqsave(&ntp_lock, flags);
+	raw_spin_lock_irqsave(&ntp_lock, flags);
 
 	/* clear the error bits, they will be set again if needed */
 	time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
@@ -911,7 +911,7 @@ void hardpps(const struct timespec *phas
 	 * just start the frequency interval */
 	if (unlikely(pps_fbase.tv_sec == 0)) {
 		pps_fbase = *raw_ts;
-		spin_unlock_irqrestore(&ntp_lock, flags);
+		raw_spin_unlock_irqrestore(&ntp_lock, flags);
 		return;
 	}
 
@@ -926,7 +926,7 @@ void hardpps(const struct timespec *phas
 		time_status |= STA_PPSJITTER;
 		/* restart the frequency calibration interval */
 		pps_fbase = *raw_ts;
-		spin_unlock_irqrestore(&ntp_lock, flags);
+		raw_spin_unlock_irqrestore(&ntp_lock, flags);
 		pr_err("hardpps: PPSJITTER: bad pulse\n");
 		return;
 	}
@@ -943,7 +943,7 @@ void hardpps(const struct timespec *phas
 
 	hardpps_update_phase(pts_norm.nsec);
 
-	spin_unlock_irqrestore(&ntp_lock, flags);
+	raw_spin_unlock_irqrestore(&ntp_lock, flags);
 }
 EXPORT_SYMBOL(hardpps);
 
Index: linux-3.4/arch/Kconfig
===================================================================
--- linux-3.4.orig/arch/Kconfig
+++ linux-3.4/arch/Kconfig
@@ -6,6 +6,7 @@ config OPROFILE
 	tristate "OProfile system profiling"
 	depends on PROFILING
 	depends on HAVE_OPROFILE
+	depends on !PREEMPT_RT_FULL
 	select RING_BUFFER
 	select RING_BUFFER_ALLOW_SWAP
 	help
Index: linux-3.4/drivers/net/Kconfig
===================================================================
--- linux-3.4.orig/drivers/net/Kconfig
+++ linux-3.4/drivers/net/Kconfig
@@ -156,6 +156,7 @@ config MACVTAP
 
 config NETCONSOLE
 	tristate "Network console logging support"
+	depends on !PREEMPT_RT_FULL
 	---help---
 	If you want to log kernel messages over the network, enable this.
 	See <file:Documentation/networking/netconsole.txt> for details.
Index: linux-3.4/mm/Kconfig
===================================================================
--- linux-3.4.orig/mm/Kconfig
+++ linux-3.4/mm/Kconfig
@@ -313,7 +313,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
 
 config TRANSPARENT_HUGEPAGE
 	bool "Transparent Hugepage Support"
-	depends on X86 && MMU
+	depends on X86 && MMU && !PREEMPT_RT_FULL
 	select COMPACTION
 	help
 	  Transparent Hugepages allows the kernel to use huge pages and
Index: linux-3.4/init/Makefile
===================================================================
--- linux-3.4.orig/init/Makefile
+++ linux-3.4/init/Makefile
@@ -29,4 +29,4 @@ silent_chk_compile.h = :
 include/generated/compile.h: FORCE
 	@$($(quiet)chk_compile.h)
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(KBUILD_CFLAGS)"
+	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CONFIG_PREEMPT_RT_FULL)" "$(CC) $(KBUILD_CFLAGS)"
Index: linux-3.4/scripts/mkcompile_h
===================================================================
--- linux-3.4.orig/scripts/mkcompile_h
+++ linux-3.4/scripts/mkcompile_h
@@ -4,7 +4,8 @@ TARGET=$1
 ARCH=$2
 SMP=$3
 PREEMPT=$4
-CC=$5
+RT=$5
+CC=$6
 
 vecho() { [ "${quiet}" = "silent_" ] || echo "$@" ; }
 
@@ -57,6 +58,7 @@ UTS_VERSION="#$VERSION"
 CONFIG_FLAGS=""
 if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
 if [ -n "$PREEMPT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"; fi
+if [ -n "$RT" ] ; then CONFIG_FLAGS="$CONFIG_FLAGS RT"; fi
 UTS_VERSION="$UTS_VERSION $CONFIG_FLAGS $TIMESTAMP"
 
 # Truncate to maximum length
