diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst
index 2efed9926c3f9..54a79d03438a0 100644
--- a/Documentation/RCU/checklist.rst
+++ b/Documentation/RCU/checklist.rst
@@ -214,8 +214,8 @@ over a rather long period of time, but improvements are always welcome!
 	the rest of the system.
 
 7.	As of v4.20, a given kernel implements only one RCU flavor,
-	which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y.
-	If the updater uses call_rcu() or synchronize_rcu(),
+	which is RCU-sched for PREEMPTION=n and RCU-preempt for
+	PREEMPTION=y. If the updater uses call_rcu() or synchronize_rcu(),
 	then the corresponding readers my use rcu_read_lock() and
 	rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
 	or any pair of primitives that disables and re-enables preemption,
diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
index c9ab6af4d3be9..e97d1b4876ef4 100644
--- a/Documentation/RCU/stallwarn.rst
+++ b/Documentation/RCU/stallwarn.rst
@@ -25,7 +25,7 @@ So your kernel printed an RCU CPU stall warning.  The next question is
 
 -	A CPU looping with bottom halves disabled.
 
--	For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel
+-	For !CONFIG_PREEMPTION kernels, a CPU looping anywhere in the kernel
 	without invoking schedule().  If the looping in the kernel is
 	really expected and desirable behavior, you might need to add
 	some calls to cond_resched().
@@ -44,7 +44,7 @@ So your kernel printed an RCU CPU stall warning.  The next question is
 	result in the ``rcu_.*kthread starved for`` console-log message,
 	which will include additional debugging information.
 
--	A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might
+-	A CPU-bound real-time task in a CONFIG_PREEMPTION kernel, which might
 	happen to preempt a low-priority task in the middle of an RCU
 	read-side critical section.   This is especially damaging if
 	that low-priority task is not permitted to run on any other CPU,
diff --git a/Documentation/printk-ringbuffer.txt b/Documentation/printk-ringbuffer.txt
new file mode 100644
index 0000000000000..6bde5dbd8545b
--- /dev/null
+++ b/Documentation/printk-ringbuffer.txt
@@ -0,0 +1,377 @@
+struct printk_ringbuffer
+------------------------
+John Ogness <john.ogness@linutronix.de>
+
+Overview
+~~~~~~~~
+As the name suggests, this ring buffer was implemented specifically to serve
+the needs of the printk() infrastructure. The ring buffer itself is not
+specific to printk and could be used for other purposes. _However_, the
+requirements and semantics of printk are rather unique. If you intend to use
+this ring buffer for anything other than printk, you need to be very clear on
+its features, behavior, and pitfalls.
+
+Features
+^^^^^^^^
+The printk ring buffer has the following features:
+
+- single global buffer
+- resides in initialized data section (available at early boot)
+- lockless readers
+- supports multiple writers
+- supports multiple non-consuming readers
+- safe from any context (including NMI)
+- groups bytes into variable length blocks (referenced by entries)
+- entries tagged with sequence numbers
+
+Behavior
+^^^^^^^^
+Since the printk ring buffer readers are lockless, there exists no
+synchronization between readers and writers. Basically writers are the tasks
+in control and may overwrite any and all committed data at any time and from
+any context. For this reason readers can miss entries if they are overwritten
+before the reader was able to access the data. The reader API implementation
+is such that reader access to entries is atomic, so there is no risk of
+readers having to deal with partial or corrupt data. Also, entries are
+tagged with sequence numbers so readers can recognize if entries were missed.
+
+Writing to the ring buffer consists of 2 steps. First a writer must reserve
+an entry of desired size. After this step the writer has exclusive access
+to the memory region. Once the data has been written to memory, it needs to
+be committed to the ring buffer. After this step the entry has been inserted
+into the ring buffer and assigned an appropriate sequence number.
+
+Once committed, a writer must no longer access the data directly. This is
+because the data may have been overwritten and no longer exists. If a
+writer must access the data, it should either keep a private copy before
+committing the entry or use the reader API to gain access to the data.
+
+Because of how the data backend is implemented, entries that have been
+reserved but not yet committed act as barriers, preventing future writers
+from filling the ring buffer beyond the location of the reserved but not
+yet committed entry region. For this reason it is *important* that writers
+perform both reserve and commit as quickly as possible. Also, be aware that
+preemption and local interrupts are disabled and writing to the ring buffer
+is processor-reentrant locked during the reserve/commit window. Writers in
+NMI contexts can still preempt any other writers, but as long as these
+writers do not write a large amount of data with respect to the ring buffer
+size, this should not become an issue.
+
+API
+~~~
+
+Declaration
+^^^^^^^^^^^
+The printk ring buffer can be instantiated as a static structure:
+
+ /* declare a static struct printk_ringbuffer */
+ #define DECLARE_STATIC_PRINTKRB(name, szbits, cpulockptr)
+
+The value of szbits specifies the size of the ring buffer in bits. The
+cpulockptr field is a pointer to a prb_cpulock struct that is used to
+perform processor-reentrant spin locking for the writers. It is specified
+externally because it may be used for multiple ring buffers (or other
+code) to synchronize writers without risk of deadlock.
+
+Here is an example of a declaration of a printk ring buffer specifying a
+32KB (2^15) ring buffer:
+
+....
+DECLARE_STATIC_PRINTKRB_CPULOCK(rb_cpulock);
+DECLARE_STATIC_PRINTKRB(rb, 15, &rb_cpulock);
+....
+
+If writers will be using multiple ring buffers and the ordering of that usage
+is not clear, the same prb_cpulock should be used for both ring buffers.
+
+Writer API
+^^^^^^^^^^
+The writer API consists of 2 functions. The first is to reserve an entry in
+the ring buffer, the second is to commit that data to the ring buffer. The
+reserved entry information is stored within a provided `struct prb_handle`.
+
+ /* reserve an entry */
+ char *prb_reserve(struct prb_handle *h, struct printk_ringbuffer *rb,
+                   unsigned int size);
+
+ /* commit a reserved entry to the ring buffer */
+ void prb_commit(struct prb_handle *h);
+
+Here is an example of a function to write data to a ring buffer:
+
+....
+int write_data(struct printk_ringbuffer *rb, char *data, int size)
+{
+    struct prb_handle h;
+    char *buf;
+
+    buf = prb_reserve(&h, rb, size);
+    if (!buf)
+        return -1;
+    memcpy(buf, data, size);
+    prb_commit(&h);
+
+    return 0;
+}
+....
+
+Pitfalls
+++++++++
+Be aware that prb_reserve() can fail. A retry might be successful, but it
+depends entirely on whether or not the next part of the ring buffer to
+overwrite belongs to reserved but not yet committed entries of other writers.
+Writers can use the prb_inc_lost() function to allow readers to notice that a
+message was lost.
+
+Reader API
+^^^^^^^^^^
+The reader API utilizes a `struct prb_iterator` to track the reader's
+position in the ring buffer.
+
+ /* declare a pre-initialized static iterator for a ring buffer */
+ #define DECLARE_STATIC_PRINTKRB_ITER(name, rbaddr)
+
+ /* initialize iterator for a ring buffer (if static macro NOT used) */
+ void prb_iter_init(struct prb_iterator *iter,
+                    struct printk_ringbuffer *rb, u64 *seq);
+
+ /* make a deep copy of an iterator */
+ void prb_iter_copy(struct prb_iterator *dest,
+                    struct prb_iterator *src);
+
+ /* non-blocking, advance to next entry (and read the data) */
+ int prb_iter_next(struct prb_iterator *iter, char *buf,
+                   int size, u64 *seq);
+
+ /* blocking, advance to next entry (and read the data) */
+ int prb_iter_wait_next(struct prb_iterator *iter, char *buf,
+                        int size, u64 *seq);
+
+ /* position iterator at the entry seq */
+ int prb_iter_seek(struct prb_iterator *iter, u64 seq);
+
+ /* read data at current position */
+ int prb_iter_data(struct prb_iterator *iter, char *buf,
+                   int size, u64 *seq);
+
+Typically prb_iter_data() is not needed because the data can be retrieved
+directly with prb_iter_next().
+
+Here is an example of a non-blocking function that will read all the data in
+a ring buffer:
+
+....
+void read_all_data(struct printk_ringbuffer *rb, char *buf, int size)
+{
+    struct prb_iterator iter;
+    u64 prev_seq = 0;
+    u64 seq;
+    int ret;
+
+    prb_iter_init(&iter, rb, NULL);
+
+    for (;;) {
+        ret = prb_iter_next(&iter, buf, size, &seq);
+        if (ret > 0) {
+            if (seq != ++prev_seq) {
+                /* "seq - prev_seq" entries missed */
+                prev_seq = seq;
+            }
+            /* process buf here */
+        } else if (ret == 0) {
+            /* hit the end, done */
+            break;
+        } else if (ret < 0) {
+            /*
+             * iterator is invalid, a writer overtook us, reset the
+             * iterator and keep going, entries were missed
+             */
+            prb_iter_init(&iter, rb, NULL);
+        }
+    }
+}
+....
+
+Pitfalls
+++++++++
+The reader's iterator can become invalid at any time because the reader was
+overtaken by a writer. Typically the reader should reset the iterator back
+to the current oldest entry (which will be newer than the entry the reader
+was at) and continue, noting the number of entries that were missed.
+
+Utility API
+^^^^^^^^^^^
+Several functions are available as convenience for external code.
+
+ /* query the size of the data buffer */
+ int prb_buffer_size(struct printk_ringbuffer *rb);
+
+ /* skip a seq number to signify a lost record */
+ void prb_inc_lost(struct printk_ringbuffer *rb);
+
+ /* processor-reentrant spin lock */
+ void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+
+ /* processor-reentrant spin unlock */
+ void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+
+Pitfalls
+++++++++
+Although the value returned by prb_buffer_size() does represent an absolute
+upper bound, the amount of data that can be stored within the ring buffer
+is actually less because of the additional storage space of a header for each
+entry.
+
+The prb_lock() and prb_unlock() functions can be used to synchronize between
+ring buffer writers and other external activities. The function of a
+processor-reentrant spin lock is to disable preemption and local interrupts
+and synchronize against other processors. It does *not* protect against
+multiple contexts of a single processor, i.e NMI.
+
+Implementation
+~~~~~~~~~~~~~~
+This section describes several of the implementation concepts and details to
+help developers better understand the code.
+
+Entries
+^^^^^^^
+All ring buffer data is stored within a single static byte array. The reason
+for this is to ensure that any pointers to the data (past and present) will
+always point to valid memory. This is important because the lockless readers
+may be preempted for long periods of time and when they resume may be working
+with expired pointers.
+
+Entries are identified by start index and size. (The start index plus size
+is the start index of the next entry.) The start index is not simply an
+offset into the byte array, but rather a logical position (lpos) that maps
+directly to byte array offsets.
+
+For example, for a byte array of 1000, an entry may have have a start index
+of 100. Another entry may have a start index of 1100. And yet another 2100.
+All of these entry are pointing to the same memory region, but only the most
+recent entry is valid. The other entries are pointing to valid memory, but
+represent entries that have been overwritten.
+
+Note that due to overflowing, the most recent entry is not necessarily the one
+with the highest lpos value. Indeed, the printk ring buffer initializes its
+data such that an overflow happens relatively quickly in order to validate the
+handling of this situation. The implementation assumes that an lpos (unsigned
+long) will never completely wrap while a reader is preempted. If this were to
+become an issue, the seq number (which never wraps) could be used to increase
+the robustness of handling this situation.
+
+Buffer Wrapping
+^^^^^^^^^^^^^^^
+If an entry starts near the end of the byte array but would extend beyond it,
+a special terminating entry (size = -1) is inserted into the byte array and
+the real entry is placed at the beginning of the byte array. This can waste
+space at the end of the byte array, but simplifies the implementation by
+allowing writers to always work with contiguous buffers.
+
+Note that the size field is the first 4 bytes of the entry header. Also note
+that calc_next() always ensures that there are at least 4 bytes left at the
+end of the byte array to allow room for a terminating entry.
+
+Ring Buffer Pointers
+^^^^^^^^^^^^^^^^^^^^
+Three pointers (lpos values) are used to manage the ring buffer:
+
+ - _tail_: points to the oldest entry
+ - _head_: points to where the next new committed entry will be
+ - _reserve_: points to where the next new reserved entry will be
+
+These pointers always maintain a logical ordering:
+
+ tail <= head <= reserve
+
+The reserve pointer moves forward when a writer reserves a new entry. The
+head pointer moves forward when a writer commits a new entry.
+
+The reserve pointer cannot overwrite the tail pointer in a wrap situation. In
+such a situation, the tail pointer must be "pushed forward", thus
+invalidating that oldest entry. Readers identify if they are accessing a
+valid entry by ensuring their entry pointer is `>= tail && < head`.
+
+If the tail pointer is equal to the head pointer, it cannot be pushed and any
+reserve operation will fail. The only resolution is for writers to commit
+their reserved entries.
+
+Processor-Reentrant Locking
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The purpose of the processor-reentrant locking is to limit the interruption
+scenarios of writers to 2 contexts. This allows for a simplified
+implementation where:
+
+- The reserve/commit window only exists on 1 processor at a time. A reserve
+  can never fail due to uncommitted entries of other processors.
+
+- When committing entries, it is trivial to handle the situation when
+  subsequent entries have already been committed, i.e. managing the head
+  pointer.
+
+Performance
+~~~~~~~~~~~
+Some basic tests were performed on a quad Intel(R) Xeon(R) CPU E5-2697 v4 at
+2.30GHz (36 cores / 72 threads). All tests involved writing a total of
+32,000,000 records at an average of 33 bytes each. Each writer was pinned to
+its own CPU and would write as fast as it could until a total of 32,000,000
+records were written. All tests involved 2 readers that were both pinned
+together to another CPU. Each reader would read as fast as it could and track
+how many of the 32,000,000 records it could read. All tests used a ring buffer
+of 16KB in size, which holds around 350 records (header + data for each
+entry).
+
+The only difference between the tests is the number of writers (and thus also
+the number of records per writer). As more writers are added, the time to
+write a record increases. This is because data pointers, modified via cmpxchg,
+and global data access in general become more contended.
+
+1 writer
+^^^^^^^^
+ runtime: 0m 18s
+ reader1: 16219900/32000000 (50%) records
+ reader2: 16141582/32000000 (50%) records
+
+2 writers
+^^^^^^^^^
+ runtime: 0m 32s
+ reader1: 16327957/32000000 (51%) records
+ reader2: 16313988/32000000 (50%) records
+
+4 writers
+^^^^^^^^^
+ runtime: 0m 42s
+ reader1: 16421642/32000000 (51%) records
+ reader2: 16417224/32000000 (51%) records
+
+8 writers
+^^^^^^^^^
+ runtime: 0m 43s
+ reader1: 16418300/32000000 (51%) records
+ reader2: 16432222/32000000 (51%) records
+
+16 writers
+^^^^^^^^^^
+ runtime: 0m 54s
+ reader1: 16539189/32000000 (51%) records
+ reader2: 16542711/32000000 (51%) records
+
+32 writers
+^^^^^^^^^^
+ runtime: 1m 13s
+ reader1: 16731808/32000000 (52%) records
+ reader2: 16735119/32000000 (52%) records
+
+Comments
+^^^^^^^^
+It is particularly interesting to compare/contrast the 1-writer and 32-writer
+tests. Despite the writing of the 32,000,000 records taking over 4 times
+longer, the readers (which perform no cmpxchg) were still unable to keep up.
+This shows that the memory contention between the increasing number of CPUs
+also has a dramatic effect on readers.
+
+It should also be noted that in all cases each reader was able to read >=50%
+of the records. This means that a single reader would have been able to keep
+up with the writer(s) in all cases, becoming slightly easier as more writers
+are added. This was the purpose of pinning 2 readers to 1 CPU: to observe how
+maximum reader performance changes.
diff --git a/arch/Kconfig b/arch/Kconfig
index af14a567b493f..222e553f3cf50 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -34,6 +34,7 @@ config OPROFILE
 	tristate "OProfile system profiling"
 	depends on PROFILING
 	depends on HAVE_OPROFILE
+	depends on !PREEMPT_RT
 	select RING_BUFFER
 	select RING_BUFFER_ALLOW_SWAP
 	help
diff --git a/arch/alpha/include/asm/spinlock_types.h b/arch/alpha/include/asm/spinlock_types.h
index 1d5716bc060be..6883bc952d224 100644
--- a/arch/alpha/include/asm/spinlock_types.h
+++ b/arch/alpha/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ALPHA_SPINLOCK_TYPES_H
 #define _ALPHA_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e00d94b166587..b7c20565754da 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -31,6 +31,7 @@ config ARM
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
@@ -64,7 +65,7 @@ config ARM
 	select HARDIRQS_SW_RESEND
 	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
-	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
+	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU && !PREEMPT_RT
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
@@ -102,6 +103,7 @@ config ARM
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
@@ -117,6 +119,7 @@ config ARM
 	select OLD_SIGSUSPEND3
 	select PCI_SYSCALL if PCI
 	select PERF_USE_VMALLOC
+	select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM
 	select RTC_LIB
 	select SYS_SUPPORTS_APM_EMULATION
 	# Above selects are sorted alphabetically; please add new ones
diff --git a/arch/arm/include/asm/spinlock_types.h b/arch/arm/include/asm/spinlock_types.h
index 5976958647fe1..a37c0803954ba 100644
--- a/arch/arm/include/asm/spinlock_types.h
+++ b/arch/arm/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 #define TICKET_SHIFT	16
 
 typedef struct {
diff --git a/arch/arm/include/asm/switch_to.h b/arch/arm/include/asm/switch_to.h
index 007d8fea71572..285e6248454fc 100644
--- a/arch/arm/include/asm/switch_to.h
+++ b/arch/arm/include/asm/switch_to.h
@@ -4,6 +4,13 @@
 
 #include <linux/thread_info.h>
 
+#if defined CONFIG_PREEMPT_RT && defined CONFIG_HIGHMEM
+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p);
+#else
+static inline void
+switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
+#endif
+
 /*
  * For v7 SMP cores running a preemptible kernel we may be pre-empted
  * during a TLB maintenance operation, so execute an inner-shareable dsb
@@ -26,6 +33,7 @@ extern struct task_struct *__switch_to(struct task_struct *, struct thread_info
 #define switch_to(prev,next,last)					\
 do {									\
 	__complete_pending_tlbi();					\
+	switch_kmaps(prev, next);					\
 	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
 } while (0)
 
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 536b6b979f634..875aaf9af9465 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -46,6 +46,7 @@ struct cpu_context_save {
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
+	int			preempt_lazy_count; /* 0 => preemptable, <0 => bug */
 	mm_segment_t		addr_limit;	/* address limit */
 	struct task_struct	*task;		/* main task structure */
 	__u32			cpu;		/* cpu */
@@ -134,7 +135,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
 #define TIF_SYSCALL_TRACE	4	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	5	/* syscall auditing active */
 #define TIF_SYSCALL_TRACEPOINT	6	/* syscall tracepoint instrumentation */
-#define TIF_SECCOMP		7	/* seccomp syscall filtering active */
+#define TIF_NEED_RESCHED_LAZY	7
+#define TIF_SECCOMP		8	/* seccomp syscall filtering active */
 
 #define TIF_USING_IWMMXT	17
 #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
@@ -143,6 +145,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -158,7 +161,8 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
  * Change these and you break ASM code in entry-common.S
  */
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
-				 _TIF_NOTIFY_RESUME | _TIF_UPROBE)
+				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
+				 _TIF_NEED_RESCHED_LAZY)
 
 #endif /* __KERNEL__ */
 #endif /* __ASM_ARM_THREAD_INFO_H */
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index a1570c8bab25a..88a0eb048ca1b 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -41,6 +41,7 @@ int main(void)
   BLANK();
   DEFINE(TI_FLAGS,		offsetof(struct thread_info, flags));
   DEFINE(TI_PREEMPT,		offsetof(struct thread_info, preempt_count));
+  DEFINE(TI_PREEMPT_LAZY,	offsetof(struct thread_info, preempt_lazy_count));
   DEFINE(TI_ADDR_LIMIT,		offsetof(struct thread_info, addr_limit));
   DEFINE(TI_TASK,		offsetof(struct thread_info, task));
   DEFINE(TI_CPU,		offsetof(struct thread_info, cpu));
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 55a47df047738..1e689a727cb9b 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -206,11 +206,18 @@ ENDPROC(__dabt_svc)
 
 #ifdef CONFIG_PREEMPTION
 	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
-	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
 	teq	r8, #0				@ if preempt count != 0
+	bne	1f				@ return from exeption
+	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
+	tst	r0, #_TIF_NEED_RESCHED		@ if NEED_RESCHED is set
+	blne	svc_preempt			@ preempt!
+
+	ldr	r8, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
+	teq	r8, #0				@ if preempt lazy count != 0
 	movne	r0, #0				@ force flags to 0
-	tst	r0, #_TIF_NEED_RESCHED
+	tst	r0, #_TIF_NEED_RESCHED_LAZY
 	blne	svc_preempt
+1:
 #endif
 
 	svc_exit r5, irq = 1			@ return from exception
@@ -225,8 +232,14 @@ ENDPROC(__irq_svc)
 1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
 	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
 	tst	r0, #_TIF_NEED_RESCHED
+	bne	1b
+	tst	r0, #_TIF_NEED_RESCHED_LAZY
 	reteq	r8				@ go again
-	b	1b
+	ldr	r0, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
+	teq	r0, #0				@ if preempt lazy count != 0
+	beq	1b
+	ret	r8				@ go again
+
 #endif
 
 __und_fault:
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 271cb8a1eba1e..fd039b1b37319 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -53,7 +53,9 @@ saved_pc	.req	lr
 	cmp	r2, #TASK_SIZE
 	blne	addr_limit_check_failed
 	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
-	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+	tst	r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP)
+	bne	fast_work_pending
+	tst	r1, #_TIF_SECCOMP
 	bne	fast_work_pending
 
 
@@ -90,8 +92,11 @@ ENDPROC(ret_fast_syscall)
 	cmp	r2, #TASK_SIZE
 	blne	addr_limit_check_failed
 	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
-	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+	tst	r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP)
+	bne	do_slower_path
+	tst	r1, #_TIF_SECCOMP
 	beq	no_work_pending
+do_slower_path:
  UNWIND(.fnend		)
 ENDPROC(ret_fast_syscall)
 
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index c1892f733f208..fb8c029549012 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -649,7 +649,8 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 	 */
 	trace_hardirqs_off();
 	do {
-		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
+		if (likely(thread_flags & (_TIF_NEED_RESCHED |
+					   _TIF_NEED_RESCHED_LAZY))) {
 			schedule();
 		} else {
 			if (unlikely(!user_mode(regs)))
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 5d9da61eff622..7f83a013dccca 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -680,11 +680,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 		break;
 
 	case IPI_CPU_BACKTRACE:
-		printk_nmi_enter();
 		irq_enter();
 		nmi_cpu_backtrace(regs);
 		irq_exit();
-		printk_nmi_exit();
 		break;
 
 	default:
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index efa4020250315..59487ee9fd612 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -400,6 +400,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 	if (addr < TASK_SIZE)
 		return do_page_fault(addr, fsr, regs);
 
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	if (user_mode(regs))
 		goto bad_area;
 
@@ -470,6 +473,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
 static int
 do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	do_bad_area(addr, fsr, regs);
 	return 0;
 }
diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
index 187fab227b509..954a115f62054 100644
--- a/arch/arm/mm/highmem.c
+++ b/arch/arm/mm/highmem.c
@@ -31,8 +31,14 @@ static inline pte_t get_fixmap_pte(unsigned long vaddr)
 	return *ptep;
 }
 
+static unsigned int fixmap_idx(int type)
+{
+	return FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+}
+
 void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 {
+	pte_t pte = mk_pte(page, kmap_prot);
 	unsigned int idx;
 	unsigned long vaddr;
 	void *kmap;
@@ -53,7 +59,7 @@ void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 
 	type = kmap_atomic_idx_push();
 
-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+	idx = fixmap_idx(type);
 	vaddr = __fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
@@ -61,13 +67,16 @@ void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 	 * Make sure it was indeed properly unmapped.
 	 */
 	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+#endif
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
 #endif
 	/*
 	 * When debugging is off, kunmap_atomic leaves the previous mapping
 	 * in place, so the contained TLB flush ensures the TLB is updated
 	 * with the new mapping.
 	 */
-	set_fixmap_pte(idx, mk_pte(page, prot));
+	set_fixmap_pte(idx, pte);
 
 	return (void *)vaddr;
 }
@@ -80,16 +89,19 @@ void kunmap_atomic_high(void *kvaddr)
 
 	if (kvaddr >= (void *)FIXADDR_START) {
 		type = kmap_atomic_idx();
-		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+		idx = fixmap_idx(type);
 
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 #ifdef CONFIG_DEBUG_HIGHMEM
 		BUG_ON(vaddr != __fix_to_virt(idx));
-		set_fixmap_pte(idx, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */
 #endif
+		set_fixmap_pte(idx, __pte(0));
 		kmap_atomic_idx_pop();
 	} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
 		/* this address was obtained through kmap_high_get() */
@@ -100,22 +112,51 @@ EXPORT_SYMBOL(kunmap_atomic_high);
 
 void *kmap_atomic_pfn(unsigned long pfn)
 {
+	pte_t pte = pfn_pte(pfn, kmap_prot);
 	unsigned long vaddr;
 	int idx, type;
 	struct page *page = pfn_to_page(pfn);
 
-	preempt_disable();
+	migrate_disable();
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
 	type = kmap_atomic_idx_push();
-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+	idx = fixmap_idx(type);
 	vaddr = __fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
 #endif
-	set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_fixmap_pte(idx, pte);
 
 	return (void *)vaddr;
 }
+
+#if defined CONFIG_PREEMPT_RT
+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	int i;
+
+	/*
+	 * Clear @prev's kmap_atomic mappings
+	 */
+	for (i = 0; i < prev_p->kmap_idx; i++) {
+		int idx = fixmap_idx(i);
+
+		set_fixmap_pte(idx, __pte(0));
+	}
+	/*
+	 * Restore @next_p's kmap_atomic mappings
+	 */
+	for (i = 0; i < next_p->kmap_idx; i++) {
+		int idx = fixmap_idx(i);
+
+		if (!pte_none(next_p->kmap_pte[i]))
+			set_fixmap_pte(idx, next_p->kmap_pte[i]);
+	}
+}
+#endif
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d232837cbeee..4da217d5b84c2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -75,6 +75,7 @@ config ARM64
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
 	select ARCH_SUPPORTS_NUMA_BALANCING
+	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
 	select ARCH_WANT_DEFAULT_BPF_JIT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
@@ -169,6 +170,7 @@ config ARM64
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_FUTEX_CMPXCHG if FUTEX
@@ -190,6 +192,7 @@ config ARM64
 	select PCI_DOMAINS_GENERIC if PCI
 	select PCI_ECAM if (ACPI && PCI)
 	select PCI_SYSCALL if PCI
+	select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM
 	select POWER_RESET
 	select POWER_SUPPLY
 	select SPARSE_IRQ
diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index 80e946b2abee2..3b19db2db1ed0 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h
@@ -70,13 +70,36 @@ static inline bool __preempt_count_dec_and_test(void)
 	 * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE
 	 * pair.
 	 */
-	return !pc || !READ_ONCE(ti->preempt_count);
+	if (!pc || !READ_ONCE(ti->preempt_count))
+		return true;
+#ifdef CONFIG_PREEMPT_LAZY
+	if ((pc & ~PREEMPT_NEED_RESCHED))
+		return false;
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
+	return false;
+#endif
 }
 
 static inline bool should_resched(int preempt_offset)
 {
+#ifdef CONFIG_PREEMPT_LAZY
+	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
+	if (pc == preempt_offset)
+		return true;
+
+	if ((pc & ~PREEMPT_NEED_RESCHED) != preempt_offset)
+		return false;
+
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
 	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
 	return pc == preempt_offset;
+#endif
 }
 
 #ifdef CONFIG_PREEMPTION
diff --git a/arch/arm64/include/asm/spinlock_types.h b/arch/arm64/include/asm/spinlock_types.h
index 18782f0c47212..6672b05350b4e 100644
--- a/arch/arm64/include/asm/spinlock_types.h
+++ b/arch/arm64/include/asm/spinlock_types.h
@@ -5,10 +5,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
-# error "please don't include this file directly"
-#endif
-
 #include <asm-generic/qspinlock_types.h>
 #include <asm-generic/qrwlock_types.h>
 
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 5e784e16ee895..5d9f16f92c11e 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -29,6 +29,7 @@ struct thread_info {
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
 	u64			ttbr0;		/* saved TTBR0_EL1 */
 #endif
+	int			preempt_lazy_count;	/* 0 => preemptable, <0 => bug */
 	union {
 		u64		preempt_count;	/* 0 => preemptible, <0 => bug */
 		struct {
@@ -67,6 +68,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define TIF_FOREIGN_FPSTATE	3	/* CPU's FP state is not current's */
 #define TIF_UPROBE		4	/* uprobe breakpoint or singlestep */
 #define TIF_FSCHECK		5	/* Check FS is USER_DS on return */
+#define TIF_NEED_RESCHED_LAZY	6
 #define TIF_SYSCALL_TRACE	8	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	9	/* syscall auditing */
 #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
@@ -93,14 +95,16 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define _TIF_SYSCALL_EMU	(1 << TIF_SYSCALL_EMU)
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
 #define _TIF_FSCHECK		(1 << TIF_FSCHECK)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_SINGLESTEP		(1 << TIF_SINGLESTEP)
 #define _TIF_32BIT		(1 << TIF_32BIT)
 #define _TIF_SVE		(1 << TIF_SVE)
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
-				 _TIF_UPROBE | _TIF_FSCHECK)
+				 _TIF_UPROBE | _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
 
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
 				 _TIF_SYSCALL_EMU)
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 7d32fc959b1a0..b2f29bd2ae871 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -30,6 +30,7 @@ int main(void)
   BLANK();
   DEFINE(TSK_TI_FLAGS,		offsetof(struct task_struct, thread_info.flags));
   DEFINE(TSK_TI_PREEMPT,	offsetof(struct task_struct, thread_info.preempt_count));
+  DEFINE(TSK_TI_PREEMPT_LAZY,	offsetof(struct task_struct, thread_info.preempt_lazy_count));
   DEFINE(TSK_TI_ADDR_LIMIT,	offsetof(struct task_struct, thread_info.addr_limit));
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
   DEFINE(TSK_TI_TTBR0,		offsetof(struct task_struct, thread_info.ttbr0));
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 55af8b504b65a..de7cd345c633e 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -624,9 +624,18 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKING
 	mrs	x0, daif
 	orr	x24, x24, x0
 alternative_else_nop_endif
-	cbnz	x24, 1f				// preempt count != 0 || NMI return path
-	bl	arm64_preempt_schedule_irq	// irq en/disable is done inside
+
+	cbz	x24, 1f					// (need_resched + count) == 0
+	cbnz	w24, 2f					// count != 0
+
+	ldr	w24, [tsk, #TSK_TI_PREEMPT_LAZY]	// get preempt lazy count
+	cbnz	w24, 2f					// preempt lazy count != 0
+
+	ldr	x0, [tsk, #TSK_TI_FLAGS]		// get flags
+	tbz	x0, #TIF_NEED_RESCHED_LAZY, 2f		// needs rescheduling?
 1:
+	bl	arm64_preempt_schedule_irq		// irq en/disable is done inside
+2:
 #endif
 
 #ifdef CONFIG_ARM64_PSEUDO_NMI
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 55c8f3ec6705d..638a41b27febb 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -224,6 +224,16 @@ static void sve_free(struct task_struct *task)
 	__sve_free(task);
 }
 
+static void *sve_free_atomic(struct task_struct *task)
+{
+	void *sve_state = task->thread.sve_state;
+
+	WARN_ON(test_tsk_thread_flag(task, TIF_SVE));
+
+	task->thread.sve_state = NULL;
+	return sve_state;
+}
+
 /*
  * TIF_SVE controls whether a task can use SVE without trapping while
  * in userspace, and also the way a task's FPSIMD/SVE state is stored
@@ -1020,6 +1030,7 @@ void fpsimd_thread_switch(struct task_struct *next)
 void fpsimd_flush_thread(void)
 {
 	int vl, supported_vl;
+	void *mem = NULL;
 
 	if (!system_supports_fpsimd())
 		return;
@@ -1032,7 +1043,7 @@ void fpsimd_flush_thread(void)
 
 	if (system_supports_sve()) {
 		clear_thread_flag(TIF_SVE);
-		sve_free(current);
+		mem = sve_free_atomic(current);
 
 		/*
 		 * Reset the task vector length as required.
@@ -1066,6 +1077,7 @@ void fpsimd_flush_thread(void)
 	}
 
 	put_cpu_fpsimd_context();
+	kfree(mem);
 }
 
 /*
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 3b4f31f35e458..441a970fc7ceb 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -921,7 +921,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 		/* Check valid user FS if needed */
 		addr_limit_user_check();
 
-		if (thread_flags & _TIF_NEED_RESCHED) {
+		if (thread_flags & _TIF_NEED_RESCHED_MASK) {
 			/* Unmask Debug and SError for the next task */
 			local_daif_restore(DAIF_PROCCTX_NOIRQ);
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 46dc3d75cf135..04dc03bf83c7c 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -678,7 +678,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		 * involves poking the GIC, which must be done in a
 		 * non-preemptible context.
 		 */
-		preempt_disable();
+		migrate_disable();
 
 		kvm_pmu_flush_hwstate(vcpu);
 
@@ -727,7 +727,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 				kvm_timer_sync_user(vcpu);
 			kvm_vgic_sync_hwstate(vcpu);
 			local_irq_enable();
-			preempt_enable();
+			migrate_enable();
 			continue;
 		}
 
@@ -799,7 +799,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		/* Exit types that need handling before we can be preempted */
 		handle_exit_early(vcpu, ret);
 
-		preempt_enable();
+		migrate_enable();
 
 		ret = handle_exit(vcpu, ret);
 	}
diff --git a/arch/hexagon/include/asm/spinlock_types.h b/arch/hexagon/include/asm/spinlock_types.h
index 19d233497ba52..de72fb23016dc 100644
--- a/arch/hexagon/include/asm/spinlock_types.h
+++ b/arch/hexagon/include/asm/spinlock_types.h
@@ -8,10 +8,6 @@
 #ifndef _ASM_SPINLOCK_TYPES_H
 #define _ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
diff --git a/arch/ia64/include/asm/spinlock_types.h b/arch/ia64/include/asm/spinlock_types.h
index 6e345fefcdcab..681408d6816fb 100644
--- a/arch/ia64/include/asm/spinlock_types.h
+++ b/arch/ia64/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ASM_IA64_SPINLOCK_TYPES_H
 #define _ASM_IA64_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index c95fa3a2484cf..bef168c387490 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2652,7 +2652,7 @@ config MIPS_CRC_SUPPORT
 #
 config HIGHMEM
 	bool "High Memory Support"
-	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA
+	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA && !PREEMPT_RT
 
 config CPU_SUPPORTS_HIGHMEM
 	bool
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 65bed1fdeaad7..c08ba01d3f4c3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -144,6 +144,7 @@ config PPC
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select ARCH_OPTIONAL_KERNEL_RWX		if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
 	select ARCH_USE_QUEUED_RWLOCKS		if PPC_QUEUED_SPINLOCKS
@@ -226,6 +227,7 @@ config PPC
 	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select MMU_GATHER_RCU_TABLE_FREE
 	select MMU_GATHER_PAGE_SIZE
 	select HAVE_REGS_AND_STACK_ACCESS_API
@@ -247,6 +249,7 @@ config PPC
 	select OLD_SIGSUSPEND
 	select PCI_DOMAINS			if PCI
 	select PCI_SYSCALL			if PCI
+	select HAVE_POSIX_CPU_TIMERS_TASK_WORK	if !KVM
 	select PPC_DAWR				if PPC64
 	select RTC_LIB
 	select SPARSE_IRQ
@@ -404,7 +407,7 @@ menu "Kernel options"
 
 config HIGHMEM
 	bool "High memory support"
-	depends on PPC32
+	depends on PPC32 && !PREEMPT_RT
 
 source "kernel/Kconfig.hz"
 
diff --git a/arch/powerpc/include/asm/spinlock_types.h b/arch/powerpc/include/asm/spinlock_types.h
index c5d742f18021d..cc6922a011ba1 100644
--- a/arch/powerpc/include/asm/spinlock_types.h
+++ b/arch/powerpc/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ASM_POWERPC_SPINLOCK_TYPES_H
 #define _ASM_POWERPC_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 #ifdef CONFIG_PPC_QUEUED_SPINLOCKS
 #include <asm-generic/qspinlock_types.h>
 #include <asm-generic/qrwlock_types.h>
diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h
index 1c8460e235838..b1653c160bab9 100644
--- a/arch/powerpc/include/asm/stackprotector.h
+++ b/arch/powerpc/include/asm/stackprotector.h
@@ -24,7 +24,11 @@ static __always_inline void boot_init_stack_canary(void)
 	unsigned long canary;
 
 	/* Try to get a semi random initial value. */
+#ifdef CONFIG_PREEMPT_RT
+	canary = (unsigned long)&canary;
+#else
 	canary = get_random_canary();
+#endif
 	canary ^= mftb();
 	canary ^= LINUX_VERSION_CODE;
 	canary &= CANARY_MASK;
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index ca6c970257049..3eda5d38c4182 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -48,6 +48,8 @@
 struct thread_info {
 	int		preempt_count;		/* 0 => preemptable,
 						   <0 => BUG */
+	int             preempt_lazy_count;	/* 0 => preemptable,
+						   <0 => BUG */
 	unsigned long	local_flags;		/* private flags for thread */
 #ifdef CONFIG_LIVEPATCH
 	unsigned long *livepatch_sp;
@@ -98,11 +100,12 @@ void arch_setup_new_exec(void);
 #define TIF_SINGLESTEP		8	/* singlestepping active */
 #define TIF_NOHZ		9	/* in adaptive nohz mode */
 #define TIF_SECCOMP		10	/* secure computing */
-#define TIF_RESTOREALL		11	/* Restore all regs (implies NOERROR) */
-#define TIF_NOERROR		12	/* Force successful syscall return */
+
+#define TIF_NEED_RESCHED_LAZY	11	/* lazy rescheduling necessary */
+#define TIF_SYSCALL_TRACEPOINT	12	/* syscall tracepoint instrumentation */
+
 #define TIF_NOTIFY_RESUME	13	/* callback before returning to user */
 #define TIF_UPROBE		14	/* breakpointed or single-stepping */
-#define TIF_SYSCALL_TRACEPOINT	15	/* syscall tracepoint instrumentation */
 #define TIF_EMULATE_STACK_STORE	16	/* Is an instruction emulation
 						for stack store? */
 #define TIF_MEMDIE		17	/* is terminating due to OOM killer */
@@ -111,6 +114,9 @@ void arch_setup_new_exec(void);
 #endif
 #define TIF_POLLING_NRFLAG	19	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_32BIT		20	/* 32 bit binary */
+#define TIF_RESTOREALL		21	/* Restore all regs (implies NOERROR) */
+#define TIF_NOERROR		22	/* Force successful syscall return */
+
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
@@ -130,6 +136,7 @@ void arch_setup_new_exec(void);
 #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
 #define _TIF_EMULATE_STACK_STORE	(1<<TIF_EMULATE_STACK_STORE)
 #define _TIF_NOHZ		(1<<TIF_NOHZ)
+#define _TIF_NEED_RESCHED_LAZY	(1<<TIF_NEED_RESCHED_LAZY)
 #define _TIF_FSCHECK		(1<<TIF_FSCHECK)
 #define _TIF_SYSCALL_EMU	(1<<TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_DOTRACE	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
@@ -139,8 +146,9 @@ void arch_setup_new_exec(void);
 #define _TIF_USER_WORK_MASK	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
 				 _TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
-				 _TIF_FSCHECK)
+				 _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
 #define _TIF_PERSYSCALL_MASK	(_TIF_RESTOREALL|_TIF_NOERROR)
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
 
 /* Bits in local_flags */
 /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 8711c2164b45a..3ded638add454 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -188,6 +188,7 @@ int main(void)
 	OFFSET(TI_FLAGS, thread_info, flags);
 	OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
 	OFFSET(TI_PREEMPT, thread_info, preempt_count);
+	OFFSET(TI_PREEMPT_LAZY, thread_info, preempt_lazy_count);
 
 #ifdef CONFIG_PPC64
 	OFFSET(DCACHEL1BLOCKSIZE, ppc64_caches, l1d.block_size);
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index f4d0af8e1136a..22907e6419385 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -415,7 +415,9 @@ _GLOBAL(DoSyscall)
 	mtmsr	r10
 	lwz	r9,TI_FLAGS(r2)
 	li	r8,-MAX_ERRNO
-	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
+	lis	r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
+	ori	r0,r0, (_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
+	and.	r0,r9,r0
 	bne-	syscall_exit_work
 	cmplw	0,r3,r8
 	blt+	syscall_exit_cont
@@ -532,13 +534,13 @@ _ASM_NOKPROBE_SYMBOL(syscall_exit_finish)
 	b	syscall_dotrace_cont
 
 syscall_exit_work:
-	andi.	r0,r9,_TIF_RESTOREALL
+	andis.	r0,r9,_TIF_RESTOREALL@h
 	beq+	0f
 	REST_NVGPRS(r1)
 	b	2f
 0:	cmplw	0,r3,r8
 	blt+	1f
-	andi.	r0,r9,_TIF_NOERROR
+	andis.	r0,r9,_TIF_NOERROR@h
 	bne-	1f
 	lwz	r11,_CCR(r1)			/* Load CR */
 	neg	r3,r3
@@ -547,12 +549,12 @@ _ASM_NOKPROBE_SYMBOL(syscall_exit_finish)
 
 1:	stw	r6,RESULT(r1)	/* Save result */
 	stw	r3,GPR3(r1)	/* Update return value */
-2:	andi.	r0,r9,(_TIF_PERSYSCALL_MASK)
+2:	andis.	r0,r9,(_TIF_PERSYSCALL_MASK)@h
 	beq	4f
 
 	/* Clear per-syscall TIF flags if any are set.  */
 
-	li	r11,_TIF_PERSYSCALL_MASK
+	lis	r11,(_TIF_PERSYSCALL_MASK)@h
 	addi	r12,r2,TI_FLAGS
 3:	lwarx	r8,0,r12
 	andc	r8,r8,r11
@@ -942,7 +944,14 @@ user_exc_return:		/* r10 contains MSR_KERNEL here */
 	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
 	bne	restore_kuap
 	andi.	r8,r8,_TIF_NEED_RESCHED
+	bne+	1f
+	lwz	r0,TI_PREEMPT_LAZY(r2)
+	cmpwi	0,r0,0          /* if non-zero, just restore regs and return */
+	bne	restore_kuap
+	lwz	r0,TI_FLAGS(r2)
+	andi.	r0,r0,_TIF_NEED_RESCHED_LAZY
 	beq+	restore_kuap
+1:
 	lwz	r3,_MSR(r1)
 	andi.	r0,r3,MSR_EE	/* interrupts off? */
 	beq	restore_kuap	/* don't schedule if so */
@@ -1265,7 +1274,7 @@ _ASM_NOKPROBE_SYMBOL(ret_from_mcheck_exc)
 #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
 
 do_work:			/* r10 contains MSR_KERNEL here */
-	andi.	r0,r9,_TIF_NEED_RESCHED
+	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
 	beq	do_user_signal
 
 do_resched:			/* r10 contains MSR_KERNEL here */
@@ -1286,7 +1295,7 @@ do_resched:			/* r10 contains MSR_KERNEL here */
 	SYNC
 	mtmsr	r10		/* disable interrupts */
 	lwz	r9,TI_FLAGS(r2)
-	andi.	r0,r9,_TIF_NEED_RESCHED
+	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
 	bne-	do_resched
 	andi.	r0,r9,_TIF_USER_WORK_MASK
 	beq	restore_user
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index d9ed79415100f..50f7a1b8a6c85 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -1081,7 +1081,7 @@ _GLOBAL(ret_from_except_lite)
 	li	r10, -1
 	mtspr	SPRN_DBSR,r10
 	b	restore
-1:	andi.	r0,r4,_TIF_NEED_RESCHED
+1:	andi.	r0,r4,_TIF_NEED_RESCHED_MASK
 	beq	2f
 	bl	restore_interrupts
 	SCHEDULE_USER
@@ -1133,12 +1133,20 @@ _GLOBAL(ret_from_except_lite)
 	bne-	0b
 1:
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	/* Check if we need to preempt */
-	andi.	r0,r4,_TIF_NEED_RESCHED
-	beq+	restore
-	/* Check that preempt_count() == 0 and interrupts are enabled */
 	lwz	r8,TI_PREEMPT(r9)
+	cmpwi	0,r8,0		/* if non-zero, just restore regs and return */
+	bne	restore
+	andi.	r0,r4,_TIF_NEED_RESCHED
+	bne+	check_count
+
+	andi.	r0,r4,_TIF_NEED_RESCHED_LAZY
+	beq+	restore
+	lwz	r8,TI_PREEMPT_LAZY(r9)
+
+	/* Check that preempt_count() == 0 and interrupts are enabled */
+check_count:
 	cmpwi	cr0,r8,0
 	bne	restore
 	ld	r0,SOFTE(r1)
@@ -1159,7 +1167,7 @@ _GLOBAL(ret_from_except_lite)
 	 * interrupted after loading SRR0/1.
 	 */
 	wrteei	0
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 restore:
 	/*
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index bf21ebd361900..171e41ae389b9 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -784,10 +784,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_mostly;
 void *softirq_ctx[NR_CPUS] __read_mostly;
 void *hardirq_ctx[NR_CPUS] __read_mostly;
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	call_do_softirq(softirq_ctx[smp_processor_id()]);
 }
+#endif
 
 irq_hw_number_t virq_to_hw(unsigned int virq)
 {
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index b24f866fef816..a4b903822d502 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -31,6 +31,7 @@
  * We store the saved ksp_limit in the unused part
  * of the STACK_FRAME_OVERHEAD
  */
+#ifndef CONFIG_PREEMPT_RT
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	stw	r0,4(r1)
@@ -46,6 +47,7 @@ _GLOBAL(call_do_softirq)
 	stw	r10,THREAD+KSP_LIMIT(r2)
 	mtlr	r0
 	blr
+#endif
 
 /*
  * void call_do_irq(struct pt_regs *regs, void *sp);
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 7bb46ad982072..442832bf599f7 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -27,6 +27,7 @@
 
 	.text
 
+#ifndef CONFIG_PREEMPT_RT
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	std	r0,16(r1)
@@ -37,6 +38,7 @@ _GLOBAL(call_do_softirq)
 	ld	r0,16(r1)
 	mtlr	r0
 	blr
+#endif
 
 _GLOBAL(call_do_irq)
 	mflr	r0
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index 8e50818aa50bc..4be309aedbb49 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -193,7 +193,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
 	ti_flags = READ_ONCE(*ti_flagsp);
 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
 		local_irq_enable();
-		if (ti_flags & _TIF_NEED_RESCHED) {
+		if (ti_flags & _TIF_NEED_RESCHED_MASK) {
 			schedule();
 		} else {
 			/*
@@ -277,7 +277,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
 	ti_flags = READ_ONCE(*ti_flagsp);
 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
 		local_irq_enable(); /* returning to user: may enable */
-		if (ti_flags & _TIF_NEED_RESCHED) {
+		if (ti_flags & _TIF_NEED_RESCHED_MASK) {
 			schedule();
 		} else {
 			if (ti_flags & _TIF_SIGPENDING)
@@ -361,11 +361,14 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
 		/* Returning to a kernel context with local irqs enabled. */
 		WARN_ON_ONCE(!(regs->msr & MSR_EE));
 again:
-		if (IS_ENABLED(CONFIG_PREEMPT)) {
+		if (IS_ENABLED(CONFIG_PREEMPTION)) {
 			/* Return to preemptible kernel context */
 			if (unlikely(*ti_flagsp & _TIF_NEED_RESCHED)) {
 				if (preempt_count() == 0)
 					preempt_schedule_irq();
+			} else if (unlikely(*ti_flagsp & _TIF_NEED_RESCHED_LAZY)) {
+				if (current_thread_info()->preempt_lazy_count == 0)
+					preempt_schedule_irq();
 			}
 		}
 
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index d1ebe152f2107..f5a1468b8d5b9 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -170,7 +170,6 @@ extern void panic_flush_kmsg_start(void)
 
 extern void panic_flush_kmsg_end(void)
 {
-	printk_safe_flush_on_panic();
 	kmsg_dump(KMSG_DUMP_PANIC);
 	bust_spinlocks(0);
 	debug_locks_off();
@@ -260,12 +259,17 @@ static char *get_mmu_str(void)
 
 static int __die(const char *str, struct pt_regs *regs, long err)
 {
+	const char *pr = "";
+
 	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
+
 	printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n",
 	       IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
 	       PAGE_SIZE / 1024, get_mmu_str(),
-	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
+	       pr,
 	       IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
 	       IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "",
 	       debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index af3c15a1d41eb..8ae46c5945d07 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -181,11 +181,6 @@ static void watchdog_smp_panic(int cpu, u64 tb)
 
 	wd_smp_unlock(&flags);
 
-	printk_safe_flush();
-	/*
-	 * printk_safe_flush() seems to require another print
-	 * before anything actually goes out to console.
-	 */
 	if (sysctl_hardlockup_all_cpu_backtrace)
 		trigger_allbutself_cpu_backtrace();
 
diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
index 549591d9aaa2c..efb5bfe93f705 100644
--- a/arch/powerpc/kvm/Kconfig
+++ b/arch/powerpc/kvm/Kconfig
@@ -178,6 +178,7 @@ config KVM_E500MC
 config KVM_MPIC
 	bool "KVM in-kernel MPIC emulation"
 	depends on KVM && E500
+	depends on !PREEMPT_RT
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQFD
 	select HAVE_KVM_IRQ_ROUTING
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 6d47b4a3ce395..15eef4d607ed3 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include <linux/iommu.h>
 #include <linux/rculist.h>
+#include <linux/local_lock.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -177,6 +178,7 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift,
 }
 
 static DEFINE_PER_CPU(__be64 *, tce_page);
+static DEFINE_LOCAL_IRQ_LOCK(tcp_page_lock);
 
 static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 				     long npages, unsigned long uaddr,
@@ -198,7 +200,8 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		                           direction, attrs);
 	}
 
-	local_irq_save(flags);	/* to protect tcep and the page behind it */
+	/* to protect tcep and the page behind it */
+	local_lock_irqsave(tcp_page_lock, flags);
 
 	tcep = __this_cpu_read(tce_page);
 
@@ -209,7 +212,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
 		/* If allocation fails, fall back to the loop implementation */
 		if (!tcep) {
-			local_irq_restore(flags);
+			local_unlock_irqrestore(tcp_page_lock, flags);
 			return tce_build_pSeriesLP(tbl->it_index, tcenum,
 					tbl->it_page_shift,
 					npages, uaddr, direction, attrs);
@@ -244,7 +247,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 		tcenum += limit;
 	} while (npages > 0 && !rc);
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(tcp_page_lock, flags);
 
 	if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
 		ret = (int)rc;
@@ -415,13 +418,14 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
 				DMA_BIDIRECTIONAL, 0);
 	}
 
-	local_irq_disable();	/* to protect tcep and the page behind it */
+	/* to protect tcep and the page behind it */
+	local_lock_irq(tcp_page_lock);
 	tcep = __this_cpu_read(tce_page);
 
 	if (!tcep) {
 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
 		if (!tcep) {
-			local_irq_enable();
+			local_unlock_irq(tcp_page_lock);
 			return -ENOMEM;
 		}
 		__this_cpu_write(tce_page, tcep);
@@ -467,7 +471,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
 
 	/* error cleanup: caller will clear whole range */
 
-	local_irq_enable();
+	local_unlock_irq(tcp_page_lock);
 	return rc;
 }
 
diff --git a/arch/s390/include/asm/spinlock_types.h b/arch/s390/include/asm/spinlock_types.h
index cfed272e4fd59..8e28e8176ec88 100644
--- a/arch/s390/include/asm/spinlock_types.h
+++ b/arch/s390/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	int lock;
 } __attribute__ ((aligned (4))) arch_spinlock_t;
diff --git a/arch/sh/include/asm/spinlock_types.h b/arch/sh/include/asm/spinlock_types.h
index e82369f286a20..22ca9a98bbb8b 100644
--- a/arch/sh/include/asm/spinlock_types.h
+++ b/arch/sh/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SH_SPINLOCK_TYPES_H
 #define __ASM_SH_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index 5717c7cbdd97a..c4e46252377ed 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -148,6 +148,7 @@ void irq_ctx_exit(int cpu)
 	hardirq_ctx[cpu] = NULL;
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	struct thread_info *curctx;
@@ -175,6 +176,7 @@ void do_softirq_own_stack(void)
 		  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 	);
 }
+#endif
 #else
 static inline void handle_one_irq(unsigned int irq)
 {
diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 3ec9f1402aad3..eb21682abfcb1 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -854,6 +854,7 @@ void __irq_entry handler_irq(int pil, struct pt_regs *regs)
 	set_irq_regs(old_regs);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	void *orig_sp, *sp = softirq_stack[smp_processor_id()];
@@ -868,6 +869,7 @@ void do_softirq_own_stack(void)
 	__asm__ __volatile__("mov %0, %%sp"
 			     : : "r" (orig_sp));
 }
+#endif
 
 #ifdef CONFIG_HOTPLUG_CPU
 void fixup_irqs(void)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7101ac64bb209..13a1f43f60347 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -92,6 +92,7 @@ config X86
 	select ARCH_SUPPORTS_ACPI
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
+	select ARCH_SUPPORTS_RT
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
@@ -208,6 +209,7 @@ config X86
 	select HAVE_PCI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
 	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
 	select HAVE_REGS_AND_STACK_ACCESS_API
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index ad8a7188a2bf7..c9eb0ed6c284d 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -376,14 +376,14 @@ static int ecb_encrypt(struct skcipher_request *req)
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	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);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -398,14 +398,14 @@ static int ecb_decrypt(struct skcipher_request *req)
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	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 = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -420,14 +420,14 @@ static int cbc_encrypt(struct skcipher_request *req)
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	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 = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -442,14 +442,14 @@ static int cbc_decrypt(struct skcipher_request *req)
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	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 = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -497,18 +497,20 @@ static int ctr_crypt(struct skcipher_request *req)
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
+		kernel_fpu_begin();
 		aesni_ctr_enc_tfm(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			              nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 	if (walk.nbytes) {
+		kernel_fpu_begin();
 		ctr_crypt_final(ctx, &walk);
+		kernel_fpu_end();
 		err = skcipher_walk_done(&walk, 0);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
diff --git a/arch/x86/crypto/cast5_avx_glue.c b/arch/x86/crypto/cast5_avx_glue.c
index 384ccb00f9e15..2f8df8ef8644e 100644
--- a/arch/x86/crypto/cast5_avx_glue.c
+++ b/arch/x86/crypto/cast5_avx_glue.c
@@ -46,7 +46,7 @@ static inline void cast5_fpu_end(bool fpu_enabled)
 
 static int ecb_crypt(struct skcipher_request *req, bool enc)
 {
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
@@ -61,7 +61,7 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
 		u8 *wsrc = walk.src.virt.addr;
 		u8 *wdst = walk.dst.virt.addr;
 
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 
 		/* Process multi-block batch */
 		if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
@@ -90,10 +90,9 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
 		} while (nbytes >= bsize);
 
 done:
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	cast5_fpu_end(fpu_enabled);
 	return err;
 }
 
@@ -197,7 +196,7 @@ static int cbc_decrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct skcipher_walk walk;
 	unsigned int nbytes;
 	int err;
@@ -205,12 +204,11 @@ static int cbc_decrypt(struct skcipher_request *req)
 	err = skcipher_walk_virt(&walk, req, false);
 
 	while ((nbytes = walk.nbytes)) {
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 		nbytes = __cbc_decrypt(ctx, &walk);
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	cast5_fpu_end(fpu_enabled);
 	return err;
 }
 
@@ -277,7 +275,7 @@ static int ctr_crypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct skcipher_walk walk;
 	unsigned int nbytes;
 	int err;
@@ -285,13 +283,12 @@ static int ctr_crypt(struct skcipher_request *req)
 	err = skcipher_walk_virt(&walk, req, false);
 
 	while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 		nbytes = __ctr_crypt(&walk, ctx);
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	cast5_fpu_end(fpu_enabled);
-
 	if (walk.nbytes) {
 		ctr_crypt_final(&walk, ctx);
 		err = skcipher_walk_done(&walk, 0);
diff --git a/arch/x86/crypto/glue_helper.c b/arch/x86/crypto/glue_helper.c
index d3d91a0abf88f..6d07747215147 100644
--- a/arch/x86/crypto/glue_helper.c
+++ b/arch/x86/crypto/glue_helper.c
@@ -24,7 +24,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -37,7 +37,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
 		unsigned int i;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 		for (i = 0; i < gctx->num_funcs; i++) {
 			func_bytes = bsize * gctx->funcs[i].num_blocks;
 
@@ -55,10 +55,9 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
 			if (nbytes < bsize)
 				break;
 		}
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	glue_fpu_end(fpu_enabled);
 	return err;
 }
 EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
@@ -101,7 +100,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -115,7 +114,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
 		u128 last_iv;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 		/* Start of the last block. */
 		src += nbytes / bsize - 1;
 		dst += nbytes / bsize - 1;
@@ -148,10 +147,10 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
 done:
 		u128_xor(dst, dst, (u128 *)walk.iv);
 		*(u128 *)walk.iv = last_iv;
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	glue_fpu_end(fpu_enabled);
 	return err;
 }
 EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
@@ -162,7 +161,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -176,7 +175,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 		le128 ctrblk;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 
 		be128_to_le128(&ctrblk, (be128 *)walk.iv);
 
@@ -202,11 +201,10 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
 		}
 
 		le128_to_be128((be128 *)walk.iv, &ctrblk);
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	glue_fpu_end(fpu_enabled);
-
 	if (nbytes) {
 		le128 ctrblk;
 		u128 tmp;
@@ -306,8 +304,14 @@ int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
 	tweak_fn(tweak_ctx, walk.iv, walk.iv);
 
 	while (nbytes) {
+		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+					     &walk, fpu_enabled,
+					     nbytes < bsize ? bsize : nbytes);
 		nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
 
+		glue_fpu_end(fpu_enabled);
+		fpu_enabled = false;
+
 		err = skcipher_walk_done(&walk, nbytes);
 		nbytes = walk.nbytes;
 	}
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index b774c52e5411f..1786e4d9f70e8 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -23,6 +23,7 @@ extern void kernel_fpu_begin(void);
 extern void kernel_fpu_end(void);
 extern bool irq_fpu_usable(void);
 extern void fpregs_mark_activate(void);
+extern void kernel_fpu_resched(void);
 
 /*
  * Use fpregs_lock() while editing CPU's FPU registers or fpu->state.
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 69485ca13665f..314757e23c47b 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -89,17 +89,48 @@ static __always_inline void __preempt_count_sub(int val)
  * a decrement which hits zero means we have no preempt_count and should
  * reschedule.
  */
-static __always_inline bool __preempt_count_dec_and_test(void)
+static __always_inline bool ____preempt_count_dec_and_test(void)
 {
 	return GEN_UNARY_RMWcc("decl", __preempt_count, e, __percpu_arg([var]));
 }
 
+static __always_inline bool __preempt_count_dec_and_test(void)
+{
+	if (____preempt_count_dec_and_test())
+		return true;
+#ifdef CONFIG_PREEMPT_LAZY
+	if (preempt_count())
+		return false;
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
+	return false;
+#endif
+}
+
 /*
  * Returns true when we need to resched and can (barring IRQ state).
  */
 static __always_inline bool should_resched(int preempt_offset)
 {
+#ifdef CONFIG_PREEMPT_LAZY
+	u32 tmp;
+	tmp = raw_cpu_read_4(__preempt_count);
+	if (tmp == preempt_offset)
+		return true;
+
+	/* preempt count == 0 ? */
+	tmp &= ~PREEMPT_NEED_RESCHED;
+	if (tmp != preempt_offset)
+		return false;
+	/* XXX PREEMPT_LOCK_OFFSET */
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
 	return unlikely(raw_cpu_read_4(__preempt_count) == preempt_offset);
+#endif
 }
 
 #ifdef CONFIG_PREEMPTION
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
index 6fd8410a3910c..f3bf2f515edb3 100644
--- a/arch/x86/include/asm/signal.h
+++ b/arch/x86/include/asm/signal.h
@@ -28,6 +28,19 @@ typedef struct {
 #define SA_IA32_ABI	0x02000000u
 #define SA_X32_ABI	0x01000000u
 
+/*
+ * 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 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)
+#define ARCH_RT_DELAYS_SIGNAL_SEND
+#endif
+
 #ifndef CONFIG_COMPAT
 typedef sigset_t compat_sigset_t;
 #endif
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
index 7fb482f0f25b0..3df0a95c9e134 100644
--- a/arch/x86/include/asm/stackprotector.h
+++ b/arch/x86/include/asm/stackprotector.h
@@ -65,7 +65,7 @@
  */
 static __always_inline void boot_init_stack_canary(void)
 {
-	u64 canary;
+	u64 canary = 0;
 	u64 tsc;
 
 #ifdef CONFIG_X86_64
@@ -76,8 +76,14 @@ static __always_inline void boot_init_stack_canary(void)
 	 * 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
 	get_random_bytes(&canary, sizeof(canary));
+#endif
 	tsc = rdtsc();
 	canary += tsc + (tsc << 32UL);
 	canary &= CANARY_MASK;
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 267701ae3d86d..350e342d9f252 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -56,17 +56,24 @@ struct task_struct;
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	u32			status;		/* thread synchronous flags */
+	int			preempt_lazy_count;	/* 0 => lazy preemptable
+							  <0 => BUG */
 };
 
 #define INIT_THREAD_INFO(tsk)			\
 {						\
 	.flags		= 0,			\
+	.preempt_lazy_count = 0,		\
 }
 
 #else /* !__ASSEMBLY__ */
 
 #include <asm/asm-offsets.h>
 
+#define GET_THREAD_INFO(reg) \
+	_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
+	_ASM_SUB $(THREAD_SIZE),reg ;
+
 #endif
 
 /*
@@ -93,6 +100,7 @@ struct thread_info {
 #define TIF_NOTSC		16	/* TSC is not accessible in userland */
 #define TIF_IA32		17	/* IA32 compatibility process */
 #define TIF_SLD			18	/* Restore split lock detection on context switch */
+#define TIF_NEED_RESCHED_LAZY	19	/* lazy rescheduling necessary */
 #define TIF_MEMDIE		20	/* is terminating due to OOM killer */
 #define TIF_POLLING_NRFLAG	21	/* idle is polling for TIF_NEED_RESCHED */
 #define TIF_IO_BITMAP		22	/* uses I/O bitmap */
@@ -123,6 +131,7 @@ struct thread_info {
 #define _TIF_NOTSC		(1 << TIF_NOTSC)
 #define _TIF_IA32		(1 << TIF_IA32)
 #define _TIF_SLD		(1 << TIF_SLD)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
 #define _TIF_FORCED_TF		(1 << TIF_FORCED_TF)
@@ -156,6 +165,8 @@ struct thread_info {
 
 #define _TIF_WORK_CTXSW_NEXT	(_TIF_WORK_CTXSW)
 
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
+
 #define STACK_WARN		(THREAD_SIZE/8)
 
 /*
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 31125448b174d..0a3270aadfce2 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -75,11 +75,12 @@ EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 
 	inc_irq_stat(hyperv_stimer0_count);
 	if (hv_stimer0_handler)
 		hv_stimer0_handler();
-	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
+	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0, ip);
 	ack_APIC_irq();
 
 	set_irq_regs(old_regs);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index eb86a2b831b15..23aaf9e132e9f 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -158,6 +158,18 @@ void kernel_fpu_end(void)
 }
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
 
+void kernel_fpu_resched(void)
+{
+	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
+
+	if (should_resched(PREEMPT_OFFSET)) {
+		kernel_fpu_end();
+		cond_resched();
+		kernel_fpu_begin();
+	}
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_resched);
+
 /*
  * Save the FPU state (mark it for reload if necessary):
  *
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 0b79efc87be52..93c6b88b382a0 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -131,6 +131,7 @@ int irq_init_percpu_irqstack(unsigned int cpu)
 	return 0;
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	struct irq_stack *irqstk;
@@ -147,6 +148,7 @@ void do_softirq_own_stack(void)
 
 	call_on_stack(__do_softirq, isp);
 }
+#endif
 
 void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 1b4fe93a86c5c..dae70c0c055ab 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -72,7 +72,9 @@ int irq_init_percpu_irqstack(unsigned int cpu)
 	return map_irq_stack(cpu);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	run_on_irqstack_cond(__do_softirq, NULL, NULL);
 }
+#endif
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 4f2f54e1281c3..17189e47cee88 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -38,6 +38,7 @@
 #include <linux/io.h>
 #include <linux/kdebug.h>
 #include <linux/syscalls.h>
+#include <linux/highmem.h>
 
 #include <asm/ldt.h>
 #include <asm/processor.h>
@@ -126,6 +127,35 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 }
 EXPORT_SYMBOL_GPL(start_thread);
 
+#ifdef CONFIG_PREEMPT_RT
+static void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	int i;
+
+	/*
+	 * Clear @prev's kmap_atomic mappings
+	 */
+	for (i = 0; i < prev_p->kmap_idx; i++) {
+		int idx = i + KM_TYPE_NR * smp_processor_id();
+		pte_t *ptep = kmap_pte - idx;
+
+		kpte_clear_flush(ptep, __fix_to_virt(FIX_KMAP_BEGIN + idx));
+	}
+	/*
+	 * Restore @next_p's kmap_atomic mappings
+	 */
+	for (i = 0; i < next_p->kmap_idx; i++) {
+		int idx = i + KM_TYPE_NR * smp_processor_id();
+
+		if (!pte_none(next_p->kmap_pte[i]))
+			set_pte(kmap_pte - idx, next_p->kmap_pte[i]);
+	}
+}
+#else
+static inline void
+switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
+#endif
+
 
 /*
  *	switch_to(x,y) should switch tasks from x to y.
@@ -187,6 +217,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 
 	switch_to_extra(prev_p, next_p);
 
+	switch_kmaps(prev_p, next_p);
+
 	/*
 	 * Leave lazy mode, flushing any hypercalls made here.
 	 * This must be done before restoring TLS segments so
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d39d6cf1d4737..84923ca2cefe0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7496,6 +7496,14 @@ int kvm_arch_init(void *opaque)
 		goto out;
 	}
 
+#ifdef CONFIG_PREEMPT_RT
+	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
+		pr_err("RT requires X86_FEATURE_CONSTANT_TSC\n");
+		r = -EOPNOTSUPP;
+		goto out;
+	}
+#endif
+
 	r = -ENOMEM;
 	x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu),
 					  __alignof__(struct fpu), SLAB_ACCOUNT,
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index 075fe51317b0f..95da91a7c7af5 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -8,12 +8,17 @@ void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
 {
 	unsigned long vaddr;
 	int idx, type;
+	pte_t pte;
 
 	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)));
-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+	pte = mk_pte(page, prot);
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_pte(kmap_pte-idx, pte);
 	arch_flush_lazy_mmu_mode();
 
 	return (void *)vaddr;
@@ -50,6 +55,9 @@ void kunmap_atomic_high(void *kvaddr)
 		 * is a bad idea also, in case the page changes cacheability
 		 * attributes or becomes a protected page in a hypervisor.
 		 */
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 		kpte_clear_flush(kmap_pte-idx, vaddr);
 		kmap_atomic_idx_pop();
 		arch_flush_lazy_mmu_mode();
diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
index f60398aeb6445..0ef360874c752 100644
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -46,16 +46,22 @@ EXPORT_SYMBOL_GPL(iomap_free);
 
 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
 {
+	pte_t pte = pfn_pte(pfn, prot);
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
+	migrate_disable();
 	pagefault_disable();
 
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
+	WARN_ON(!pte_none(*(kmap_pte - idx)));
+
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_pte(kmap_pte - idx, pte);
 	arch_flush_lazy_mmu_mode();
 
 	return (void *)vaddr;
@@ -106,11 +112,14 @@ iounmap_atomic(void __iomem *kvaddr)
 		 * is a bad idea also, in case the page changes cacheability
 		 * attributes or becomes a protected page in a hypervisor.
 		 */
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 		kpte_clear_flush(kmap_pte-idx, vaddr);
 		kmap_atomic_idx_pop();
 	}
 
 	pagefault_enable();
-	preempt_enable();
+	migrate_enable();
 }
 EXPORT_SYMBOL_GPL(iounmap_atomic);
diff --git a/arch/xtensa/include/asm/spinlock_types.h b/arch/xtensa/include/asm/spinlock_types.h
index 64c9389254f13..dc846323b1cd7 100644
--- a/arch/xtensa/include/asm/spinlock_types.h
+++ b/arch/xtensa/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
-# error "please don't include this file directly"
-#endif
-
 #include <asm-generic/qspinlock_types.h>
 #include <asm-generic/qrwlock_types.h>
 
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b3d2785eefe93..f7f66014d7dd2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -604,6 +604,7 @@ static void blk_mq_trigger_softirq(struct request *rq)
 	if (list->next == &rq->ipi_list)
 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 
 static int blk_softirq_cpu_dead(unsigned int cpu)
@@ -617,6 +618,7 @@ static int blk_softirq_cpu_dead(unsigned int cpu)
 			 this_cpu_ptr(&blk_cpu_done));
 	raise_softirq_irqoff(BLOCK_SOFTIRQ);
 	local_irq_enable();
+	preempt_check_resched_rt();
 
 	return 0;
 }
@@ -1606,14 +1608,14 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
-		int cpu = get_cpu();
+		int cpu = get_cpu_light();
 		if (cpumask_test_cpu(cpu, hctx->cpumask)) {
 			__blk_mq_run_hw_queue(hctx);
-			put_cpu();
+			put_cpu_light();
 			return;
 		}
 
-		put_cpu();
+		put_cpu_light();
 	}
 
 	kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index a1bea0f4baa88..5f8ca8c1f59cd 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -36,6 +36,7 @@ static struct workqueue_struct *cryptd_wq;
 struct cryptd_cpu_queue {
 	struct crypto_queue queue;
 	struct work_struct work;
+	spinlock_t qlock;
 };
 
 struct cryptd_queue {
@@ -105,6 +106,7 @@ static int cryptd_init_queue(struct cryptd_queue *queue,
 		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
 		crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
 		INIT_WORK(&cpu_queue->work, cryptd_queue_worker);
+		spin_lock_init(&cpu_queue->qlock);
 	}
 	pr_info("cryptd: max_cpu_qlen set to %d\n", max_cpu_qlen);
 	return 0;
@@ -129,8 +131,10 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,
 	struct cryptd_cpu_queue *cpu_queue;
 	refcount_t *refcnt;
 
-	cpu = get_cpu();
-	cpu_queue = this_cpu_ptr(queue->cpu_queue);
+	cpu_queue = raw_cpu_ptr(queue->cpu_queue);
+	spin_lock_bh(&cpu_queue->qlock);
+	cpu = smp_processor_id();
+
 	err = crypto_enqueue_request(&cpu_queue->queue, request);
 
 	refcnt = crypto_tfm_ctx(request->tfm);
@@ -146,7 +150,7 @@ static int cryptd_enqueue_request(struct cryptd_queue *queue,
 	refcount_inc(refcnt);
 
 out_put_cpu:
-	put_cpu();
+	spin_unlock_bh(&cpu_queue->qlock);
 
 	return err;
 }
@@ -162,16 +166,11 @@ static void cryptd_queue_worker(struct work_struct *work)
 	cpu_queue = container_of(work, struct cryptd_cpu_queue, work);
 	/*
 	 * Only handle one request at a time to avoid hogging crypto workqueue.
-	 * preempt_disable/enable is used to prevent being preempted by
-	 * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent
-	 * cryptd_enqueue_request() being accessed from software interrupts.
 	 */
-	local_bh_disable();
-	preempt_disable();
+	spin_lock_bh(&cpu_queue->qlock);
 	backlog = crypto_get_backlog(&cpu_queue->queue);
 	req = crypto_dequeue_request(&cpu_queue->queue);
-	preempt_enable();
-	local_bh_enable();
+	spin_unlock_bh(&cpu_queue->qlock);
 
 	if (!req)
 		return;
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9100ac36670af..4bd301dd22c3b 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -56,6 +56,40 @@ static void zram_free_page(struct zram *zram, size_t index);
 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 				u32 index, int offset, struct bio *bio);
 
+#ifdef CONFIG_PREEMPT_RT
+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
+{
+	size_t index;
+
+	for (index = 0; index < num_pages; index++)
+		spin_lock_init(&zram->table[index].lock);
+}
+
+static int zram_slot_trylock(struct zram *zram, u32 index)
+{
+	int ret;
+
+	ret = spin_trylock(&zram->table[index].lock);
+	if (ret)
+		__set_bit(ZRAM_LOCK, &zram->table[index].flags);
+	return ret;
+}
+
+static void zram_slot_lock(struct zram *zram, u32 index)
+{
+	spin_lock(&zram->table[index].lock);
+	__set_bit(ZRAM_LOCK, &zram->table[index].flags);
+}
+
+static void zram_slot_unlock(struct zram *zram, u32 index)
+{
+	__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
+	spin_unlock(&zram->table[index].lock);
+}
+
+#else
+
+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
 
 static int zram_slot_trylock(struct zram *zram, u32 index)
 {
@@ -71,6 +105,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index)
 {
 	bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
 }
+#endif
 
 static inline bool init_done(struct zram *zram)
 {
@@ -1158,6 +1193,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 
 	if (!huge_class_size)
 		huge_class_size = zs_huge_class_size(zram->mem_pool);
+	zram_meta_init_table_locks(zram, num_pages);
 	return true;
 }
 
@@ -1220,6 +1256,7 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 	unsigned long handle;
 	unsigned int size;
 	void *src, *dst;
+	struct zcomp_strm *zstrm;
 
 	zram_slot_lock(zram, index);
 	if (zram_test_flag(zram, index, ZRAM_WB)) {
@@ -1250,6 +1287,7 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 
 	size = zram_get_obj_size(zram, index);
 
+	zstrm = zcomp_stream_get(zram->comp);
 	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
 	if (size == PAGE_SIZE) {
 		dst = kmap_atomic(page);
@@ -1257,14 +1295,13 @@ static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 		kunmap_atomic(dst);
 		ret = 0;
 	} else {
-		struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
 
 		dst = kmap_atomic(page);
 		ret = zcomp_decompress(zstrm, src, size, dst);
 		kunmap_atomic(dst);
-		zcomp_stream_put(zram->comp);
 	}
 	zs_unmap_object(zram->mem_pool, handle);
+	zcomp_stream_put(zram->comp);
 	zram_slot_unlock(zram, index);
 
 	/* Should NEVER happen. Return bio error if it does. */
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index f2fd46daa7604..7e4dd447e1ddd 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -63,6 +63,7 @@ struct zram_table_entry {
 		unsigned long element;
 	};
 	unsigned long flags;
+	spinlock_t lock;
 #ifdef CONFIG_ZRAM_MEMORY_TRACKING
 	ktime_t ac_time;
 #endif
diff --git a/drivers/char/random.c b/drivers/char/random.c
index d20ba1b104ca3..081a1a4b9d70f 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1252,28 +1252,27 @@ static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs)
 	return *ptr;
 }
 
-void add_interrupt_randomness(int irq, int irq_flags)
+void add_interrupt_randomness(int irq, int irq_flags, __u64 ip)
 {
 	struct entropy_store	*r;
 	struct fast_pool	*fast_pool = this_cpu_ptr(&irq_randomness);
-	struct pt_regs		*regs = get_irq_regs();
 	unsigned long		now = jiffies;
 	cycles_t		cycles = random_get_entropy();
 	__u32			c_high, j_high;
-	__u64			ip;
 	unsigned long		seed;
 	int			credit = 0;
 
 	if (cycles == 0)
-		cycles = get_reg(fast_pool, regs);
+		cycles = get_reg(fast_pool, NULL);
 	c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0;
 	j_high = (sizeof(now) > 4) ? now >> 32 : 0;
 	fast_pool->pool[0] ^= cycles ^ j_high ^ irq;
 	fast_pool->pool[1] ^= now ^ c_high;
-	ip = regs ? instruction_pointer(regs) : _RET_IP_;
+	if (!ip)
+		ip = _RET_IP_;
 	fast_pool->pool[2] ^= ip;
 	fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
-		get_reg(fast_pool, regs);
+		get_reg(fast_pool, NULL);
 
 	fast_mix(fast_pool);
 	add_interrupt_bench(cycles);
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 1784530b8387b..c08cbb306636b 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -20,7 +20,6 @@
 #include "tpm-dev.h"
 
 static struct workqueue_struct *tpm_dev_wq;
-static DEFINE_MUTEX(tpm_dev_wq_lock);
 
 static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
 				u8 *buf, size_t bufsiz)
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 0b214963539de..39cee10c59f88 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -49,6 +49,31 @@ static inline struct tpm_tis_tcg_phy *to_tpm_tis_tcg_phy(struct tpm_tis_data *da
 	return container_of(data, struct tpm_tis_tcg_phy, priv);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * Flushes previous write operations to chip so that a subsequent
+ * ioread*()s won't stall a cpu.
+ */
+static inline void tpm_tis_flush(void __iomem *iobase)
+{
+	ioread8(iobase + TPM_ACCESS(0));
+}
+#else
+#define tpm_tis_flush(iobase) do { } while (0)
+#endif
+
+static inline void tpm_tis_iowrite8(u8 b, void __iomem *iobase, u32 addr)
+{
+	iowrite8(b, iobase + addr);
+	tpm_tis_flush(iobase);
+}
+
+static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
+{
+	iowrite32(b, iobase + addr);
+	tpm_tis_flush(iobase);
+}
+
 static bool interrupts = true;
 module_param(interrupts, bool, 0444);
 MODULE_PARM_DESC(interrupts, "Enable interrupts");
@@ -146,7 +171,7 @@ static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
 
 	while (len--)
-		iowrite8(*value++, phy->iobase + addr);
+		tpm_tis_iowrite8(*value++, phy->iobase, addr);
 
 	return 0;
 }
@@ -173,7 +198,7 @@ static int tpm_tcg_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 {
 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
 
-	iowrite32(value, phy->iobase + addr);
+	tpm_tis_iowrite32(value, phy->iobase, addr);
 
 	return 0;
 }
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3aa07c3b51369..25a8e81d17423 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -62,7 +62,7 @@ struct mm_struct efi_mm = {
 
 struct workqueue_struct *efi_rts_wq;
 
-static bool disable_runtime;
+static bool disable_runtime = IS_ENABLED(CONFIG_PREEMPT_RT);
 static int __init setup_noefi(char *arg)
 {
 	disable_runtime = true;
@@ -93,6 +93,9 @@ static int __init parse_efi_cmdline(char *str)
 	if (parse_option_str(str, "noruntime"))
 		disable_runtime = true;
 
+	if (parse_option_str(str, "runtime"))
+		disable_runtime = false;
+
 	if (parse_option_str(str, "nosoftreserve"))
 		set_bit(EFI_MEM_NO_SOFT_RESERVE, &efi.flags);
 
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index e8f809161c75f..c5700f44422ec 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -29,6 +29,7 @@
 #include <linux/async.h>
 #include <linux/i2c.h>
 #include <linux/sched/clock.h>
+#include <linux/local_lock.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_crtc.h>
@@ -1149,6 +1150,7 @@ struct intel_crtc {
 #ifdef CONFIG_DEBUG_FS
 	struct intel_pipe_crc pipe_crc;
 #endif
+	local_lock_t pipe_update_lock;
 };
 
 struct intel_plane {
diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
index c89f5f7ccb06e..62b8248d2ee79 100644
--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -118,7 +118,7 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
 			"PSR idle timed out 0x%x, atomic update may fail\n",
 			psr_status);
 
-	local_irq_disable();
+	local_lock_irq(&crtc->pipe_update_lock);
 
 	crtc->debug.min_vbl = min;
 	crtc->debug.max_vbl = max;
@@ -143,11 +143,11 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
 			break;
 		}
 
-		local_irq_enable();
+		local_unlock_irq(&crtc->pipe_update_lock);
 
 		timeout = schedule_timeout(timeout);
 
-		local_irq_disable();
+		local_lock_irq(&crtc->pipe_update_lock);
 	}
 
 	finish_wait(wq, &wait);
@@ -180,7 +180,7 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
 	return;
 
 irq_disable:
-	local_irq_disable();
+	local_lock_irq(&crtc->pipe_update_lock);
 }
 
 /**
@@ -218,7 +218,7 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
 		new_crtc_state->uapi.event = NULL;
 	}
 
-	local_irq_enable();
+	local_unlock_irq(&crtc->pipe_update_lock);
 
 	if (intel_vgpu_active(dev_priv))
 		return;
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 8ec3eecf3e397..31bb901530419 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -59,9 +59,10 @@ static int __engine_unpark(struct intel_wakeref *wf)
 
 static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
 {
-	unsigned long flags;
+	unsigned long flags = 0;
 
-	local_irq_save(flags);
+	if (!force_irqthreads)
+		local_irq_save(flags);
 	mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
 
 	return flags;
@@ -71,7 +72,8 @@ static inline void __timeline_mark_unlock(struct intel_context *ce,
 					  unsigned long flags)
 {
 	mutex_release(&ce->timeline->mutex.dep_map, _THIS_IP_);
-	local_irq_restore(flags);
+	if (!force_irqthreads)
+		local_irq_restore(flags);
 }
 
 #else
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 1fa67700d8f49..4ee735b91e973 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -865,6 +865,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
 	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -916,6 +917,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 
diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index a4addcc649782..396b6598694d3 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -2,6 +2,10 @@
 #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
 #define _I915_TRACE_H_
 
+#ifdef CONFIG_PREEMPT_RT
+#define NOTRACE
+#endif
+
 #include <linux/stringify.h>
 #include <linux/types.h>
 #include <linux/tracepoint.h>
@@ -778,7 +782,7 @@ DEFINE_EVENT(i915_request, i915_request_add,
 	    TP_ARGS(rq)
 );
 
-#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS)
+#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) && !defined(NOTRACE)
 DEFINE_EVENT(i915_request, i915_request_submit,
 	     TP_PROTO(struct i915_request *rq),
 	     TP_ARGS(rq)
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index e0ae911ef427d..781edf5504360 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -1822,6 +1822,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
 	struct radeon_device *rdev = dev->dev_private;
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -1914,6 +1915,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	/* Decode into vertical and horizontal scanout position. */
 	*vpos = position & 0x1fff;
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 40e2b9f91163c..d9de4813ffac8 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -18,6 +18,7 @@
 #include <linux/atomic.h>
 #include <linux/hyperv.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 
 #include "hv_trace.h"
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 910b6e90866ca..3cc8f52f2336f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -22,6 +22,7 @@
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
 #include <linux/sched/task_stack.h>
+#include <linux/irq.h>
 
 #include <linux/delay.h>
 #include <linux/notifier.h>
@@ -1303,6 +1304,8 @@ static void vmbus_isr(void)
 	void *page_addr = hv_cpu->synic_event_page;
 	struct hv_message *msg;
 	union hv_synic_event_flags *event;
+	struct pt_regs *regs = get_irq_regs();
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 	bool handled = false;
 
 	if (unlikely(page_addr == NULL))
@@ -1347,7 +1350,7 @@ static void vmbus_isr(void)
 			tasklet_schedule(&hv_cpu->msg_dpc);
 	}
 
-	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
+	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0, ip);
 }
 
 /*
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index ce9429ca6ddea..29ccbd6acf43f 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT
 
 config LEDS_TRIGGER_CPU
 	bool "LED CPU Trigger"
+	depends on !PREEMPT_RT
 	help
 	  This allows LEDs to be controlled by active CPUs. This shows
 	  the active CPUs across an array of LEDs so you can see which
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 225380efd1e24..7ae33e2edd350 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -2077,8 +2077,9 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 	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++;
@@ -2137,7 +2138,8 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
 			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();
 }
 
 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
@@ -6902,6 +6904,7 @@ static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
 			__func__, cpu);
 		return -ENOMEM;
 	}
+	spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
 	return 0;
 }
 
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 16fc29472f5c0..d16edbdcde6e6 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -627,6 +627,7 @@ 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
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 0f9274960dc6b..dc97e4f1f4ad2 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -1452,11 +1452,11 @@ static int fcoe_rcv(struct sk_buff *skb, struct net_device *netdev,
 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;
 }
@@ -1641,11 +1641,11 @@ static inline int fcoe_filter_frames(struct fc_lport *lport,
 		return 0;
 	}
 
-	stats = per_cpu_ptr(lport->stats, get_cpu());
+	stats = per_cpu_ptr(lport->stats, get_cpu_light());
 	stats->InvalidCRCCount++;
 	if (stats->InvalidCRCCount < 5)
 		printk(KERN_WARNING "fcoe: dropping frame with CRC error\n");
-	put_cpu();
+	put_cpu_light();
 	return -EINVAL;
 }
 
@@ -1686,7 +1686,7 @@ static void fcoe_recv_frame(struct sk_buff *skb)
 	 */
 	hp = (struct fcoe_hdr *) skb_network_header(skb);
 
-	stats = per_cpu_ptr(lport->stats, get_cpu());
+	stats = per_cpu_ptr(lport->stats, get_cpu_light());
 	if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
 		if (stats->ErrorFrames < 5)
 			printk(KERN_WARNING "fcoe: FCoE version "
@@ -1718,13 +1718,13 @@ static void fcoe_recv_frame(struct sk_buff *skb)
 		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);
 }
 
diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c
index 5ea426effa609..0d6b9acc7cf81 100644
--- a/drivers/scsi/fcoe/fcoe_ctlr.c
+++ b/drivers/scsi/fcoe/fcoe_ctlr.c
@@ -828,7 +828,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip)
 
 	INIT_LIST_HEAD(&del_list);
 
-	stats = per_cpu_ptr(fip->lp->stats, get_cpu());
+	stats = per_cpu_ptr(fip->lp->stats, get_cpu_light());
 
 	list_for_each_entry_safe(fcf, next, &fip->fcfs, list) {
 		deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2;
@@ -864,7 +864,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip)
 				sel_time = fcf->time;
 		}
 	}
-	put_cpu();
+	put_cpu_light();
 
 	list_for_each_entry_safe(fcf, next, &del_list, list) {
 		/* Removes fcf from current list */
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 96a2952cf626b..1cb773a4a02e7 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -826,10 +826,10 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
 	}
 	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) {
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 52bb21205bb68..5cbcaafbb4aa2 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -130,12 +130,55 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value)
 	up->dl_write(up, value);
 }
 
+static inline void serial8250_set_IER(struct uart_8250_port *up,
+				      unsigned char ier)
+{
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	serial_out(up, UART_IER, ier);
+
+	if (is_console)
+		console_atomic_unlock(flags);
+}
+
+static inline unsigned char serial8250_clear_IER(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	unsigned int clearval = 0;
+	unsigned int prior;
+	unsigned int flags;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (up->capabilities & UART_CAP_UUE)
+		clearval = UART_IER_UUE;
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	prior = serial_port_in(port, UART_IER);
+	serial_port_out(port, UART_IER, clearval);
+
+	if (is_console)
+		console_atomic_unlock(flags);
+
+	return prior;
+}
+
 static inline bool serial8250_set_THRI(struct uart_8250_port *up)
 {
 	if (up->ier & UART_IER_THRI)
 		return false;
 	up->ier |= UART_IER_THRI;
-	serial_out(up, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	return true;
 }
 
@@ -144,7 +187,7 @@ static inline bool serial8250_clear_THRI(struct uart_8250_port *up)
 	if (!(up->ier & UART_IER_THRI))
 		return false;
 	up->ier &= ~UART_IER_THRI;
-	serial_out(up, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	return true;
 }
 
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index cae61d1ebec5a..47dd230562719 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -274,10 +274,8 @@ static void serial8250_backup_timeout(struct timer_list *t)
 	 * Must disable interrupts or else we risk racing with the interrupt
 	 * based handler.
 	 */
-	if (up->port.irq) {
-		ier = serial_in(up, UART_IER);
-		serial_out(up, UART_IER, 0);
-	}
+	if (up->port.irq)
+		ier = serial8250_clear_IER(up);
 
 	iir = serial_in(up, UART_IIR);
 
@@ -300,7 +298,7 @@ static void serial8250_backup_timeout(struct timer_list *t)
 		serial8250_tx_chars(up);
 
 	if (up->port.irq)
-		serial_out(up, UART_IER, ier);
+		serial8250_set_IER(up, ier);
 
 	spin_unlock_irqrestore(&up->port.lock, flags);
 
@@ -578,6 +576,14 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev)
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
+static void univ8250_console_write_atomic(struct console *co, const char *s,
+					  unsigned int count)
+{
+	struct uart_8250_port *up = &serial8250_ports[co->index];
+
+	serial8250_console_write_atomic(up, s, count);
+}
+
 static void univ8250_console_write(struct console *co, const char *s,
 				   unsigned int count)
 {
@@ -671,6 +677,7 @@ static int univ8250_console_match(struct console *co, char *name, int idx,
 
 static struct console univ8250_console = {
 	.name		= "ttyS",
+	.write_atomic	= univ8250_console_write_atomic,
 	.write		= univ8250_console_write,
 	.device		= uart_console_device,
 	.setup		= univ8250_console_setup,
diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c
index 0d0c80905c581..f8116a8839d8a 100644
--- a/drivers/tty/serial/8250/8250_fsl.c
+++ b/drivers/tty/serial/8250/8250_fsl.c
@@ -53,9 +53,18 @@ int fsl8250_handle_irq(struct uart_port *port)
 
 	/* Stop processing interrupts on input overrun */
 	if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) {
+		unsigned int ca_flags;
 		unsigned long delay;
+		bool is_console;
 
+		is_console = uart_console(port);
+
+		if (is_console)
+			console_atomic_lock(&ca_flags);
 		up->ier = port->serial_in(port, UART_IER);
+		if (is_console)
+			console_atomic_unlock(ca_flags);
+
 		if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
 			port->ops->stop_rx(port);
 		} else {
diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
index dde766fa465ff..f4cceca82748e 100644
--- a/drivers/tty/serial/8250/8250_ingenic.c
+++ b/drivers/tty/serial/8250/8250_ingenic.c
@@ -146,6 +146,8 @@ OF_EARLYCON_DECLARE(x1000_uart, "ingenic,x1000-uart",
 
 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
 {
+	unsigned int flags;
+	bool is_console;
 	int ier;
 
 	switch (offset) {
@@ -167,7 +169,12 @@ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
 		 * If we have enabled modem status IRQs we should enable
 		 * modem mode.
 		 */
+		is_console = uart_console(p);
+		if (is_console)
+			console_atomic_lock(&flags);
 		ier = p->serial_in(p, UART_IER);
+		if (is_console)
+			console_atomic_unlock(flags);
 
 		if (ier & UART_IER_MSI)
 			value |= UART_MCR_MDCE | UART_MCR_FCM;
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 7b0dec14c8b80..d323ff7051f69 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -213,12 +213,37 @@ static void mtk8250_shutdown(struct uart_port *port)
 
 static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
 {
-	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	ier = serial_in(up, UART_IER);
+	serial_out(up, UART_IER, ier & (~mask));
+
+	if (is_console)
+		console_atomic_unlock(flags);
 }
 
 static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
 {
-	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+
+	if (uart_console(port))
+		console_atomic_lock(&flags);
+
+	ier = serial_in(up, UART_IER);
+	serial_out(up, UART_IER, ier | mask);
+
+	if (uart_console(port))
+		console_atomic_unlock(flags);
 }
 
 static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index c71d647eb87a0..4325a15be5731 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -757,7 +757,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
 			serial_out(p, UART_EFR, UART_EFR_ECB);
 			serial_out(p, UART_LCR, 0);
 		}
-		serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
+		serial8250_set_IER(p, sleep ? UART_IERX_SLEEP : 0);
 		if (p->capabilities & UART_CAP_EFR) {
 			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
 			serial_out(p, UART_EFR, efr);
@@ -1429,7 +1429,7 @@ static void serial8250_stop_rx(struct uart_port *port)
 
 	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
 	up->port.read_status_mask &= ~UART_LSR_DR;
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 
 	serial8250_rpm_put(up);
 }
@@ -1459,7 +1459,7 @@ void serial8250_em485_stop_tx(struct uart_8250_port *p)
 		serial8250_clear_and_reinit_fifos(p);
 
 		p->ier |= UART_IER_RLSI | UART_IER_RDI;
-		serial_port_out(&p->port, UART_IER, p->ier);
+		serial8250_set_IER(p, p->ier);
 	}
 }
 EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx);
@@ -1687,7 +1687,7 @@ static void serial8250_disable_ms(struct uart_port *port)
 	mctrl_gpio_disable_ms(up->gpios);
 
 	up->ier &= ~UART_IER_MSI;
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 }
 
 static void serial8250_enable_ms(struct uart_port *port)
@@ -1703,7 +1703,7 @@ static void serial8250_enable_ms(struct uart_port *port)
 	up->ier |= UART_IER_MSI;
 
 	serial8250_rpm_get(up);
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	serial8250_rpm_put(up);
 }
 
@@ -2118,14 +2118,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
 	struct uart_8250_port *up = up_to_u8250p(port);
 
 	serial8250_rpm_get(up);
-	/*
-	 *	First save the IER then disable the interrupts
-	 */
-	ier = serial_port_in(port, UART_IER);
-	if (up->capabilities & UART_CAP_UUE)
-		serial_port_out(port, UART_IER, UART_IER_UUE);
-	else
-		serial_port_out(port, UART_IER, 0);
+	ier = serial8250_clear_IER(up);
 
 	wait_for_xmitr(up, BOTH_EMPTY);
 	/*
@@ -2138,7 +2131,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
 	 *	and restore the IER
 	 */
 	wait_for_xmitr(up, BOTH_EMPTY);
-	serial_port_out(port, UART_IER, ier);
+	serial8250_set_IER(up, ier);
 	serial8250_rpm_put(up);
 }
 
@@ -2441,7 +2434,7 @@ void serial8250_do_shutdown(struct uart_port *port)
 	 */
 	spin_lock_irqsave(&port->lock, flags);
 	up->ier = 0;
-	serial_port_out(port, UART_IER, 0);
+	serial8250_set_IER(up, 0);
 	spin_unlock_irqrestore(&port->lock, flags);
 
 	synchronize_irq(port->irq);
@@ -2768,7 +2761,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
 	if (up->capabilities & UART_CAP_RTOIE)
 		up->ier |= UART_IER_RTOIE;
 
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 
 	if (up->capabilities & UART_CAP_EFR) {
 		unsigned char efr = 0;
@@ -3234,7 +3227,7 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults);
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
-static void serial8250_console_putchar(struct uart_port *port, int ch)
+static void serial8250_console_putchar_locked(struct uart_port *port, int ch)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
@@ -3242,6 +3235,18 @@ static void serial8250_console_putchar(struct uart_port *port, int ch)
 	serial_port_out(port, UART_TX, ch);
 }
 
+static void serial8250_console_putchar(struct uart_port *port, int ch)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int flags;
+
+	wait_for_xmitr(up, UART_LSR_THRE);
+
+	console_atomic_lock(&flags);
+	serial8250_console_putchar_locked(port, ch);
+	console_atomic_unlock(flags);
+}
+
 /*
  *	Restore serial console when h/w power-off detected
  */
@@ -3263,6 +3268,32 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 	serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
 }
 
+void serial8250_console_write_atomic(struct uart_8250_port *up,
+				     const char *s, unsigned int count)
+{
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+
+	console_atomic_lock(&flags);
+
+	touch_nmi_watchdog();
+
+	ier = serial8250_clear_IER(up);
+
+	if (atomic_fetch_inc(&up->console_printing)) {
+		uart_console_write(port, "\n", 1,
+				   serial8250_console_putchar_locked);
+	}
+	uart_console_write(port, s, count, serial8250_console_putchar_locked);
+	atomic_dec(&up->console_printing);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial8250_set_IER(up, ier);
+
+	console_atomic_unlock(flags);
+}
+
 /*
  *	Print a string to the serial port trying not to disturb
  *	any possible real use of the port...
@@ -3279,24 +3310,12 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	struct uart_port *port = &up->port;
 	unsigned long flags;
 	unsigned int ier;
-	int locked = 1;
 
 	touch_nmi_watchdog();
 
-	if (oops_in_progress)
-		locked = spin_trylock_irqsave(&port->lock, flags);
-	else
-		spin_lock_irqsave(&port->lock, flags);
+	spin_lock_irqsave(&port->lock, flags);
 
-	/*
-	 *	First save the IER then disable the interrupts
-	 */
-	ier = serial_port_in(port, UART_IER);
-
-	if (up->capabilities & UART_CAP_UUE)
-		serial_port_out(port, UART_IER, UART_IER_UUE);
-	else
-		serial_port_out(port, UART_IER, 0);
+	ier = serial8250_clear_IER(up);
 
 	/* check scratch reg to see if port powered off during system sleep */
 	if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
@@ -3310,7 +3329,9 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 		mdelay(port->rs485.delay_rts_before_send);
 	}
 
+	atomic_inc(&up->console_printing);
 	uart_console_write(port, s, count, serial8250_console_putchar);
+	atomic_dec(&up->console_printing);
 
 	/*
 	 *	Finally, wait for transmitter to become empty
@@ -3323,8 +3344,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 		if (em485->tx_stopped)
 			up->rs485_stop_tx(up);
 	}
-
-	serial_port_out(port, UART_IER, ier);
+	serial8250_set_IER(up, ier);
 
 	/*
 	 *	The receive handling will happen properly because the
@@ -3336,8 +3356,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	if (up->msr_saved_flags)
 		serial8250_modem_status(up);
 
-	if (locked)
-		spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->lock, flags);
 }
 
 static unsigned int probe_baud(struct uart_port *port)
@@ -3357,6 +3376,7 @@ static unsigned int probe_baud(struct uart_port *port)
 
 int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
 {
+	struct uart_8250_port *up = up_to_u8250p(port);
 	int baud = 9600;
 	int bits = 8;
 	int parity = 'n';
@@ -3366,6 +3386,8 @@ int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
 	if (!port->iobase && !port->membase)
 		return -ENODEV;
 
+	atomic_set(&up->console_printing, 0);
+
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else if (probe)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 67498594d7d7e..e5cf42bbabf35 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2198,18 +2198,24 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 {
 	struct uart_amba_port *uap = amba_ports[co->index];
 	unsigned int old_cr = 0, new_cr;
-	unsigned long flags;
+	unsigned long flags = 0;
 	int locked = 1;
 
 	clk_enable(uap->clk);
 
-	local_irq_save(flags);
+	/*
+	 * local_irq_save(flags);
+	 *
+	 * This local_irq_save() is nonsense. If we come in via sysrq
+	 * handling then interrupts are already disabled. Aside of
+	 * that the port.sysrq check is racy on SMP regardless.
+	*/
 	if (uap->port.sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock(&uap->port.lock);
+		locked = spin_trylock_irqsave(&uap->port.lock, flags);
 	else
-		spin_lock(&uap->port.lock);
+		spin_lock_irqsave(&uap->port.lock, flags);
 
 	/*
 	 *	First save the CR then disable the interrupts
@@ -2235,8 +2241,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 		pl011_write(old_cr, uap, REG_CR);
 
 	if (locked)
-		spin_unlock(&uap->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&uap->port.lock, flags);
 
 	clk_disable(uap->clk);
 }
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 76b94d0ff5865..80371598efea4 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1301,13 +1301,10 @@ serial_omap_console_write(struct console *co, const char *s,
 
 	pm_runtime_get_sync(up->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
@@ -1336,8 +1333,7 @@ serial_omap_console_write(struct console *co, const char *s,
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
 	if (locked)
-		spin_unlock(&up->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
 static int __init
diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c
index 04f75a44f2432..60cbce1995a59 100644
--- a/fs/afs/dir_silly.c
+++ b/fs/afs/dir_silly.c
@@ -236,7 +236,7 @@ int afs_silly_iput(struct dentry *dentry, struct inode *inode)
 	struct dentry *alias;
 	int ret;
 
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	_enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);
 
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 6df0922e7e304..5b2371b26bf85 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -81,7 +81,7 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 	struct inode *inode;
 	struct super_block *sb = parent->d_sb;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
 
diff --git a/fs/dcache.c b/fs/dcache.c
index ea0485861d937..26a187abf13a6 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2503,9 +2503,10 @@ EXPORT_SYMBOL(d_rehash);
 static inline unsigned start_dir_add(struct inode *dir)
 {
 
+	preempt_disable_rt();
 	for (;;) {
-		unsigned n = dir->i_dir_seq;
-		if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
+		unsigned n = dir->__i_dir_seq;
+		if (!(n & 1) && cmpxchg(&dir->__i_dir_seq, n, n + 1) == n)
 			return n;
 		cpu_relax();
 	}
@@ -2513,26 +2514,30 @@ static inline unsigned start_dir_add(struct inode *dir)
 
 static inline void end_dir_add(struct inode *dir, unsigned n)
 {
-	smp_store_release(&dir->i_dir_seq, n + 2);
+	smp_store_release(&dir->__i_dir_seq, n + 2);
+	preempt_enable_rt();
 }
 
 static void d_wait_lookup(struct dentry *dentry)
 {
-	if (d_in_lookup(dentry)) {
-		DECLARE_WAITQUEUE(wait, current);
-		add_wait_queue(dentry->d_wait, &wait);
-		do {
-			set_current_state(TASK_UNINTERRUPTIBLE);
-			spin_unlock(&dentry->d_lock);
-			schedule();
-			spin_lock(&dentry->d_lock);
-		} while (d_in_lookup(dentry));
-	}
+	struct swait_queue __wait;
+
+	if (!d_in_lookup(dentry))
+		return;
+
+	INIT_LIST_HEAD(&__wait.task_list);
+	do {
+		prepare_to_swait_exclusive(dentry->d_wait, &__wait, TASK_UNINTERRUPTIBLE);
+		spin_unlock(&dentry->d_lock);
+		schedule();
+		spin_lock(&dentry->d_lock);
+	} while (d_in_lookup(dentry));
+	finish_swait(dentry->d_wait, &__wait);
 }
 
 struct dentry *d_alloc_parallel(struct dentry *parent,
 				const struct qstr *name,
-				wait_queue_head_t *wq)
+				struct swait_queue_head *wq)
 {
 	unsigned int hash = name->hash;
 	struct hlist_bl_head *b = in_lookup_hash(parent, hash);
@@ -2546,7 +2551,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
 
 retry:
 	rcu_read_lock();
-	seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
+	seq = smp_load_acquire(&parent->d_inode->__i_dir_seq);
 	r_seq = read_seqbegin(&rename_lock);
 	dentry = __d_lookup_rcu(parent, name, &d_seq);
 	if (unlikely(dentry)) {
@@ -2574,7 +2579,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
 	}
 
 	hlist_bl_lock(b);
-	if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
+	if (unlikely(READ_ONCE(parent->d_inode->__i_dir_seq) != seq)) {
 		hlist_bl_unlock(b);
 		rcu_read_unlock();
 		goto retry;
@@ -2647,7 +2652,7 @@ void __d_lookup_done(struct dentry *dentry)
 	hlist_bl_lock(b);
 	dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
 	__hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
-	wake_up_all(dentry->d_wait);
+	swake_up_all(dentry->d_wait);
 	dentry->d_wait = NULL;
 	hlist_bl_unlock(b);
 	INIT_HLIST_NODE(&dentry->d_u.d_alias);
diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
index 90e3f01bd796b..ec8fd82117f4c 100644
--- a/fs/fuse/readdir.c
+++ b/fs/fuse/readdir.c
@@ -158,7 +158,7 @@ static int fuse_direntplus_link(struct file *file,
 	struct inode *dir = d_inode(parent);
 	struct fuse_conn *fc;
 	struct inode *inode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	if (!o->nodeid) {
 		/*
diff --git a/fs/inode.c b/fs/inode.c
index 72c4c347afb70..1b27d29265cfa 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -158,7 +158,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_bdev = NULL;
 	inode->i_cdev = NULL;
 	inode->i_link = NULL;
-	inode->i_dir_seq = 0;
+	inode->__i_dir_seq = 0;
 	inode->i_rdev = 0;
 	inode->dirtied_when = 0;
 
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 414beb5438836..f1cf739d63c21 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -87,7 +87,7 @@ enum {
  */
 struct io_wqe {
 	struct {
-		spinlock_t lock;
+		raw_spinlock_t lock;
 		struct io_wq_work_list work_list;
 		unsigned long hash_map;
 		unsigned flags;
@@ -148,7 +148,7 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
 
 	if (current->files != worker->restore_files) {
 		__acquire(&wqe->lock);
-		spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock_irq(&wqe->lock);
 		dropped_lock = true;
 
 		task_lock(current);
@@ -166,7 +166,7 @@ static bool __io_worker_unuse(struct io_wqe *wqe, struct io_worker *worker)
 	if (worker->mm) {
 		if (!dropped_lock) {
 			__acquire(&wqe->lock);
-			spin_unlock_irq(&wqe->lock);
+			raw_spin_unlock_irq(&wqe->lock);
 			dropped_lock = true;
 		}
 		__set_current_state(TASK_RUNNING);
@@ -220,17 +220,17 @@ static void io_worker_exit(struct io_worker *worker)
 	worker->flags = 0;
 	preempt_enable();
 
-	spin_lock_irq(&wqe->lock);
+	raw_spin_lock_irq(&wqe->lock);
 	hlist_nulls_del_rcu(&worker->nulls_node);
 	list_del_rcu(&worker->all_list);
 	if (__io_worker_unuse(wqe, worker)) {
 		__release(&wqe->lock);
-		spin_lock_irq(&wqe->lock);
+		raw_spin_lock_irq(&wqe->lock);
 	}
 	acct->nr_workers--;
 	nr_workers = wqe->acct[IO_WQ_ACCT_BOUND].nr_workers +
 			wqe->acct[IO_WQ_ACCT_UNBOUND].nr_workers;
-	spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock_irq(&wqe->lock);
 
 	/* all workers gone, wq exit can proceed */
 	if (!nr_workers && refcount_dec_and_test(&wqe->wq->refs))
@@ -504,7 +504,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 		else if (!wq_list_empty(&wqe->work_list))
 			wqe->flags |= IO_WQE_FLAG_STALLED;
 
-		spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock_irq(&wqe->lock);
 		if (!work)
 			break;
 		io_assign_current_work(worker, work);
@@ -538,17 +538,17 @@ static void io_worker_handle_work(struct io_worker *worker)
 				io_wqe_enqueue(wqe, linked);
 
 			if (hash != -1U && !next_hashed) {
-				spin_lock_irq(&wqe->lock);
+				raw_spin_lock_irq(&wqe->lock);
 				wqe->hash_map &= ~BIT_ULL(hash);
 				wqe->flags &= ~IO_WQE_FLAG_STALLED;
 				/* skip unnecessary unlock-lock wqe->lock */
 				if (!work)
 					goto get_next;
-				spin_unlock_irq(&wqe->lock);
+				raw_spin_unlock_irq(&wqe->lock);
 			}
 		} while (work);
 
-		spin_lock_irq(&wqe->lock);
+		raw_spin_lock_irq(&wqe->lock);
 	} while (1);
 }
 
@@ -563,7 +563,7 @@ static int io_wqe_worker(void *data)
 	while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
 		set_current_state(TASK_INTERRUPTIBLE);
 loop:
-		spin_lock_irq(&wqe->lock);
+		raw_spin_lock_irq(&wqe->lock);
 		if (io_wqe_run_queue(wqe)) {
 			__set_current_state(TASK_RUNNING);
 			io_worker_handle_work(worker);
@@ -574,7 +574,7 @@ static int io_wqe_worker(void *data)
 			__release(&wqe->lock);
 			goto loop;
 		}
-		spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock_irq(&wqe->lock);
 		if (signal_pending(current))
 			flush_signals(current);
 		if (schedule_timeout(WORKER_IDLE_TIMEOUT))
@@ -586,11 +586,11 @@ static int io_wqe_worker(void *data)
 	}
 
 	if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
-		spin_lock_irq(&wqe->lock);
+		raw_spin_lock_irq(&wqe->lock);
 		if (!wq_list_empty(&wqe->work_list))
 			io_worker_handle_work(worker);
 		else
-			spin_unlock_irq(&wqe->lock);
+			raw_spin_unlock_irq(&wqe->lock);
 	}
 
 	io_worker_exit(worker);
@@ -630,9 +630,9 @@ void io_wq_worker_sleeping(struct task_struct *tsk)
 
 	worker->flags &= ~IO_WORKER_F_RUNNING;
 
-	spin_lock_irq(&wqe->lock);
+	raw_spin_lock_irq(&wqe->lock);
 	io_wqe_dec_running(wqe, worker);
-	spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock_irq(&wqe->lock);
 }
 
 static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
@@ -656,7 +656,7 @@ static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
 		return false;
 	}
 
-	spin_lock_irq(&wqe->lock);
+	raw_spin_lock_irq(&wqe->lock);
 	hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
 	list_add_tail_rcu(&worker->all_list, &wqe->all_list);
 	worker->flags |= IO_WORKER_F_FREE;
@@ -665,7 +665,7 @@ static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
 	if (!acct->nr_workers && (worker->flags & IO_WORKER_F_BOUND))
 		worker->flags |= IO_WORKER_F_FIXED;
 	acct->nr_workers++;
-	spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock_irq(&wqe->lock);
 
 	if (index == IO_WQ_ACCT_UNBOUND)
 		atomic_inc(&wq->user->processes);
@@ -720,12 +720,12 @@ static int io_wq_manager(void *data)
 			if (!node_online(node))
 				continue;
 
-			spin_lock_irq(&wqe->lock);
+			raw_spin_lock_irq(&wqe->lock);
 			if (io_wqe_need_worker(wqe, IO_WQ_ACCT_BOUND))
 				fork_worker[IO_WQ_ACCT_BOUND] = true;
 			if (io_wqe_need_worker(wqe, IO_WQ_ACCT_UNBOUND))
 				fork_worker[IO_WQ_ACCT_UNBOUND] = true;
-			spin_unlock_irq(&wqe->lock);
+			raw_spin_unlock_irq(&wqe->lock);
 			if (fork_worker[IO_WQ_ACCT_BOUND])
 				create_io_worker(wq, wqe, IO_WQ_ACCT_BOUND);
 			if (fork_worker[IO_WQ_ACCT_UNBOUND])
@@ -821,10 +821,10 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
 	}
 
 	work_flags = work->flags;
-	spin_lock_irqsave(&wqe->lock, flags);
+	raw_spin_lock_irqsave(&wqe->lock, flags);
 	io_wqe_insert_work(wqe, work);
 	wqe->flags &= ~IO_WQE_FLAG_STALLED;
-	spin_unlock_irqrestore(&wqe->lock, flags);
+	raw_spin_unlock_irqrestore(&wqe->lock, flags);
 
 	if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
 	    !atomic_read(&acct->nr_running))
@@ -951,13 +951,13 @@ static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
 	unsigned long flags;
 
 retry:
-	spin_lock_irqsave(&wqe->lock, flags);
+	raw_spin_lock_irqsave(&wqe->lock, flags);
 	wq_list_for_each(node, prev, &wqe->work_list) {
 		work = container_of(node, struct io_wq_work, list);
 		if (!match->fn(work, match->data))
 			continue;
 		io_wqe_remove_pending(wqe, work, prev);
-		spin_unlock_irqrestore(&wqe->lock, flags);
+		raw_spin_unlock_irqrestore(&wqe->lock, flags);
 		io_run_cancel(work, wqe);
 		match->nr_pending++;
 		if (!match->cancel_all)
@@ -966,7 +966,7 @@ static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
 		/* not safe to continue after unlock */
 		goto retry;
 	}
-	spin_unlock_irqrestore(&wqe->lock, flags);
+	raw_spin_unlock_irqrestore(&wqe->lock, flags);
 }
 
 static void io_wqe_cancel_running_work(struct io_wqe *wqe,
@@ -1074,7 +1074,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 		}
 		atomic_set(&wqe->acct[IO_WQ_ACCT_UNBOUND].nr_running, 0);
 		wqe->wq = wq;
-		spin_lock_init(&wqe->lock);
+		raw_spin_lock_init(&wqe->lock);
 		INIT_WQ_LIST(&wqe->work_list);
 		INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
 		INIT_LIST_HEAD(&wqe->all_list);
diff --git a/fs/namei.c b/fs/namei.c
index e99e2a9da0f7d..8b7cbca327ded 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1520,7 +1520,7 @@ static struct dentry *__lookup_slow(const struct qstr *name,
 {
 	struct dentry *dentry, *old;
 	struct inode *inode = dir->d_inode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	/* Don't go there if it's already dead */
 	if (unlikely(IS_DEADDIR(inode)))
@@ -3018,7 +3018,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
 	struct dentry *dentry;
 	int error, create_error = 0;
 	umode_t mode = op->mode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	if (unlikely(IS_DEADDIR(dir_inode)))
 		return ERR_PTR(-ENOENT);
diff --git a/fs/namespace.c b/fs/namespace.c
index bae0e95b3713a..c7e53f6ba7df8 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -14,6 +14,7 @@
 #include <linux/mnt_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/namei.h>
+#include <linux/delay.h>
 #include <linux/security.h>
 #include <linux/cred.h>
 #include <linux/idr.h>
@@ -321,8 +322,11 @@ int __mnt_want_write(struct vfsmount *m)
 	 * incremented count after it has set MNT_WRITE_HOLD.
 	 */
 	smp_mb();
-	while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
-		cpu_relax();
+	while (READ_ONCE(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
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e732580fe47b3..4e7e32a2fb0d0 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -484,7 +484,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
 		unsigned long dir_verifier)
 {
 	struct qstr filename = QSTR_INIT(entry->name, entry->len);
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 	struct dentry *dentry;
 	struct dentry *alias;
 	struct inode *inode;
@@ -1662,7 +1662,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		    struct file *file, unsigned open_flags,
 		    umode_t mode)
 {
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 	struct nfs_open_context *ctx;
 	struct dentry *res;
 	struct iattr attr = { .ia_valid = ATTR_OPEN };
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index b27ebdccef703..f86c98a7ed047 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -13,7 +13,7 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/nfs_fs.h>
 #include <linux/sched.h>
-#include <linux/wait.h>
+#include <linux/swait.h>
 #include <linux/namei.h>
 #include <linux/fsnotify.h>
 
@@ -180,7 +180,7 @@ nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
 
 	data->cred = get_current_cred();
 	data->res.dir_attr = &data->dir_attr;
-	init_waitqueue_head(&data->wq);
+	init_swait_queue_head(&data->wq);
 
 	status = -EBUSY;
 	spin_lock(&dentry->d_lock);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 617db4e0faa09..9e4520113c022 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -96,6 +96,7 @@
 #include <linux/posix-timers.h>
 #include <linux/time_namespace.h>
 #include <linux/resctrl.h>
+#include <linux/swait.h>
 #include <trace/events/oom.h>
 #include "internal.h"
 #include "fd.h"
@@ -2033,7 +2034,7 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
 
 	child = d_hash_and_lookup(dir, &qname);
 	if (!child) {
-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 		child = d_alloc_parallel(dir, &qname, &wq);
 		if (IS_ERR(child))
 			goto end_instantiate;
diff --git a/fs/proc/kmsg.c b/fs/proc/kmsg.c
index b38ad552887fb..18ed6e4e0c7e7 100644
--- a/fs/proc/kmsg.c
+++ b/fs/proc/kmsg.c
@@ -18,8 +18,6 @@
 #include <linux/uaccess.h>
 #include <asm/io.h>
 
-extern wait_queue_head_t log_wait;
-
 static int kmsg_open(struct inode * inode, struct file * file)
 {
 	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
@@ -42,7 +40,7 @@ static ssize_t kmsg_read(struct file *file, char __user *buf,
 
 static __poll_t kmsg_poll(struct file *file, poll_table *wait)
 {
-	poll_wait(file, &log_wait, wait);
+	poll_wait(file, printk_wait_queue(), wait);
 	if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
 		return EPOLLIN | EPOLLRDNORM;
 	return 0;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 6c1166ccdaea5..dab5f1749ef1d 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -685,7 +685,7 @@ static bool proc_sys_fill_cache(struct file *file,
 
 	child = d_lookup(dir, &qname);
 	if (!child) {
-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 		child = d_alloc_parallel(dir, &qname, &wq);
 		if (IS_ERR(child))
 			return false;
diff --git a/include/linux/bottom_half.h b/include/linux/bottom_half.h
index a19519f4241dc..ef2366a65ba2a 100644
--- a/include/linux/bottom_half.h
+++ b/include/linux/bottom_half.h
@@ -4,6 +4,10 @@
 
 #include <linux/preempt.h>
 
+#ifdef CONFIG_PREEMPT_RT
+extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
+#else
+
 #ifdef CONFIG_TRACE_IRQFLAGS
 extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
 #else
@@ -13,6 +17,7 @@ static __always_inline void __local_bh_disable_ip(unsigned long ip, unsigned int
 	barrier();
 }
 #endif
+#endif
 
 static inline void local_bh_disable(void)
 {
diff --git a/include/linux/console.h b/include/linux/console.h
index 0670d3491e0ea..1badb57ba82f3 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -141,6 +141,7 @@ static inline int con_debug_leave(void)
 struct console {
 	char	name[16];
 	void	(*write)(struct console *, const char *, unsigned);
+	void	(*write_atomic)(struct console *, const char *, unsigned);
 	int	(*read)(struct console *, char *, unsigned);
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
@@ -150,6 +151,8 @@ struct console {
 	short	flags;
 	short	index;
 	int	cflag;
+	unsigned long printk_seq;
+	int	wrote_history;
 	void	*data;
 	struct	 console *next;
 };
@@ -230,4 +233,7 @@ extern void console_init(void);
 void dummycon_register_output_notifier(struct notifier_block *nb);
 void dummycon_unregister_output_notifier(struct notifier_block *nb);
 
+extern void console_atomic_lock(unsigned int *flags);
+extern void console_atomic_unlock(unsigned int flags);
+
 #endif /* _LINUX_CONSOLE_H */
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 65d975bf93904..1e23dd02ac4e8 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -106,7 +106,7 @@ struct dentry {
 
 	union {
 		struct list_head d_lru;		/* LRU list */
-		wait_queue_head_t *d_wait;	/* in-lookup ones only */
+		struct swait_queue_head *d_wait;	/* in-lookup ones only */
 	};
 	struct list_head d_child;	/* child of parent list */
 	struct list_head d_subdirs;	/* our children */
@@ -238,7 +238,7 @@ extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op
 extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
 extern struct dentry * d_alloc_anon(struct super_block *);
 extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
-					wait_queue_head_t *);
+					struct swait_queue_head *);
 extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
 extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index e7e45f0cc7da5..5a9e3e3769ce0 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -2,9 +2,8 @@
 #ifndef __LINUX_DEBUG_LOCKING_H
 #define __LINUX_DEBUG_LOCKING_H
 
-#include <linux/kernel.h>
 #include <linux/atomic.h>
-#include <linux/bug.h>
+#include <linux/cache.h>
 
 struct task_struct;
 
diff --git a/include/linux/delay.h b/include/linux/delay.h
index 1d0e2ce6b6d9f..02b37178b54f4 100644
--- a/include/linux/delay.h
+++ b/include/linux/delay.h
@@ -76,4 +76,10 @@ static inline void fsleep(unsigned long usecs)
 		msleep(DIV_ROUND_UP(usecs, 1000));
 }
 
+#ifdef CONFIG_PREEMPT_RT
+extern void cpu_chill(void);
+#else
+# define cpu_chill()	cpu_relax()
+#endif
+
 #endif /* defined(_LINUX_DELAY_H) */
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index efebbffcd5cc9..7f08edfa5e76b 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -69,7 +69,7 @@
 
 #define EXIT_TO_USER_MODE_WORK						\
 	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |		\
-	 _TIF_NEED_RESCHED | _TIF_PATCH_PENDING |			\
+	 _TIF_NEED_RESCHED_MASK | _TIF_PATCH_PENDING |			\
 	 ARCH_EXIT_TO_USER_MODE_WORK)
 
 /**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7519ae003a082..946b42e7c72da 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -704,7 +704,7 @@ struct inode {
 		struct block_device	*i_bdev;
 		struct cdev		*i_cdev;
 		char			*i_link;
-		unsigned		i_dir_seq;
+		unsigned		__i_dir_seq;
 	};
 
 	__u32			i_generation;
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 754f67ac4326a..c35b71f8644aa 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -115,7 +115,6 @@ extern void rcu_nmi_exit(void);
 	do {							\
 		lockdep_off();					\
 		arch_nmi_enter();				\
-		printk_nmi_enter();				\
 		BUG_ON(in_nmi() == NMI_MASK);			\
 		__preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET);	\
 	} while (0)
@@ -134,7 +133,6 @@ extern void rcu_nmi_exit(void);
 	do {							\
 		BUG_ON(!in_nmi());				\
 		__preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET);	\
-		printk_nmi_exit();				\
 		arch_nmi_exit();				\
 		lockdep_on();					\
 	} while (0)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 14e6202ce47f1..aa41a6b3d4829 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -8,6 +8,7 @@
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
+#include <linux/sched.h>
 
 #include <asm/cacheflush.h>
 
@@ -83,7 +84,7 @@ static inline void kunmap(struct page *page)
  */
 static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
-	preempt_disable();
+	migrate_disable();
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
@@ -153,7 +154,7 @@ static inline void kunmap(struct page *page)
 
 static inline void *kmap_atomic(struct page *page)
 {
-	preempt_disable();
+	migrate_disable();
 	pagefault_disable();
 	return page_address(page);
 }
@@ -178,32 +179,51 @@ static inline void kunmap_atomic_high(void *addr)
 
 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
 
+#ifndef CONFIG_PREEMPT_RT
 DECLARE_PER_CPU(int, __kmap_atomic_idx);
+#endif
 
 static inline int kmap_atomic_idx_push(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
 
-#ifdef CONFIG_DEBUG_HIGHMEM
+# ifdef CONFIG_DEBUG_HIGHMEM
 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
 	BUG_ON(idx >= KM_TYPE_NR);
-#endif
+# endif
 	return idx;
+#else
+	current->kmap_idx++;
+	BUG_ON(current->kmap_idx > KM_TYPE_NR);
+	return current->kmap_idx - 1;
+#endif
 }
 
 static inline int kmap_atomic_idx(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	return __this_cpu_read(__kmap_atomic_idx) - 1;
+#else
+	return current->kmap_idx - 1;
+#endif
 }
 
 static inline void kmap_atomic_idx_pop(void)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
+#ifndef CONFIG_PREEMPT_RT
+# ifdef CONFIG_DEBUG_HIGHMEM
 	int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 
 	BUG_ON(idx < 0);
-#else
+# else
 	__this_cpu_dec(__kmap_atomic_idx);
+# endif
+#else
+	current->kmap_idx--;
+# ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(current->kmap_idx < 0);
+# endif
 #endif
 }
 
@@ -218,7 +238,7 @@ do {                                                            \
 	BUILD_BUG_ON(__same_type((addr), struct page *));       \
 	kunmap_atomic_high(addr);                                  \
 	pagefault_enable();                                     \
-	preempt_enable();                                       \
+	migrate_enable();					\
 } while (0)
 
 
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f9aee35384610..332678fc03325 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -560,7 +560,7 @@ struct softirq_action
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
 
-#ifdef __ARCH_HAS_DO_SOFTIRQ
+#if defined(__ARCH_HAS_DO_SOFTIRQ) && !defined(CONFIG_PREEMPT_RT)
 void do_softirq_own_stack(void);
 #else
 static inline void do_softirq_own_stack(void)
@@ -575,6 +575,7 @@ extern void __raise_softirq_irqoff(unsigned int nr);
 
 extern void raise_softirq_irqoff(unsigned int nr);
 extern void raise_softirq(unsigned int nr);
+extern void softirq_check_pending_idle(void);
 
 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
 
@@ -668,7 +669,10 @@ static inline void tasklet_unlock(struct tasklet_struct *t)
 
 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 {
-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
+	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+		local_bh_disable();
+		local_bh_enable();
+	}
 }
 #else
 #define tasklet_trylock(t) 1
diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 30823780c1928..f941f2d7d71ce 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -55,4 +55,10 @@ static inline void irq_work_run(void) { }
 static inline void irq_work_single(void *arg) { }
 #endif
 
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+void irq_work_tick_soft(void);
+#else
+static inline void irq_work_tick_soft(void) { }
+#endif
+
 #endif /* _LINUX_IRQ_WORK_H */
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 5745491303e03..2b9caf39fb075 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -68,6 +68,7 @@ struct irq_desc {
 	unsigned int		irqs_unhandled;
 	atomic_t		threads_handled;
 	int			threads_handled_last;
+	u64			random_ip;
 	raw_spinlock_t		lock;
 	struct cpumask		*percpu_enabled;
 	const struct cpumask	*percpu_affinity;
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 3ed4e8771b64e..a437b2e70d379 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -71,14 +71,6 @@ do {						\
 do {						\
 	__this_cpu_dec(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 lockdep_hrtimer_enter(__hrtimer)		\
 ({							\
@@ -140,6 +132,21 @@ do {						\
 # define lockdep_irq_work_exit(__work)		do { } while (0)
 #endif
 
+#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT)
+# 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)
+#endif
+
 #if defined(CONFIG_IRQSOFF_TRACER) || \
 	defined(CONFIG_PREEMPT_TRACER)
  extern void stop_critical_timings(void);
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index c25b8e41c0ea3..b3b514a1f12fc 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -218,6 +218,10 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
  */
 # define might_sleep() \
 	do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
+# define might_sleep_no_state_check() \
+	do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
 /**
  * cant_sleep - annotation for functions that cannot sleep
  *
@@ -249,6 +253,7 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
   static inline void __might_sleep(const char *file, int line,
 				   int preempt_offset) { }
 # define might_sleep() do { might_resched(); } while (0)
+# define might_sleep_no_state_check() do { might_resched(); } while (0)
 # define cant_sleep() do { } while (0)
 # define sched_annotate_sleep() do { } while (0)
 # define non_block_start() do { } while (0)
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 3378bcbe585ea..25f6652c05d53 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -45,10 +45,8 @@ struct kmsg_dumper {
 	bool registered;
 
 	/* private state of the kmsg iterator */
-	u32 cur_idx;
-	u32 next_idx;
-	u64 cur_seq;
-	u64 next_seq;
+	u64 line_seq;
+	u64 buffer_end_seq;
 };
 
 #ifdef CONFIG_PRINTK
diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
index 4a8795b21d774..998d2c34cf0c2 100644
--- a/include/linux/local_lock_internal.h
+++ b/include/linux/local_lock_internal.h
@@ -7,33 +7,90 @@
 #include <linux/lockdep.h>
 
 typedef struct {
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#ifdef CONFIG_PREEMPT_RT
+	spinlock_t              lock;
+	struct task_struct      *owner;
+	int                     nestcnt;
+
+#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
 	struct lockdep_map	dep_map;
 	struct task_struct	*owner;
 #endif
 } local_lock_t;
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define LL_DEP_MAP_INIT(lockname)			\
+#ifdef CONFIG_PREEMPT_RT
+
+#define INIT_LOCAL_LOCK(lockname)	{	\
+	__SPIN_LOCK_UNLOCKED((lockname).lock),	\
+	.owner		= NULL,			\
+	.nestcnt	= 0,			\
+	}
+#else
+
+# ifdef CONFIG_DEBUG_LOCK_ALLOC
+#  define LL_DEP_MAP_INIT(lockname)			\
 	.dep_map = {					\
 		.name = #lockname,			\
 		.wait_type_inner = LD_WAIT_CONFIG,	\
 	}
-#else
-# define LL_DEP_MAP_INIT(lockname)
-#endif
+# else
+#  define LL_DEP_MAP_INIT(lockname)
+# endif
 
 #define INIT_LOCAL_LOCK(lockname)	{ LL_DEP_MAP_INIT(lockname) }
 
-#define __local_lock_init(lock)					\
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+
+static inline void ___local_lock_init(local_lock_t *l)
+{
+	l->owner = NULL;
+	l->nestcnt = 0;
+}
+
+#define __local_lock_init(l)					\
+do {								\
+	spin_lock_init(&(l)->lock);				\
+	___local_lock_init(l);					\
+} while (0)
+
+#else
+
+#define __local_lock_init(l)					\
 do {								\
 	static struct lock_class_key __key;			\
 								\
-	debug_check_no_locks_freed((void *)lock, sizeof(*lock));\
-	lockdep_init_map_wait(&(lock)->dep_map, #lock, &__key, 0, LD_WAIT_CONFIG);\
+	debug_check_no_locks_freed((void *)l, sizeof(*l));	\
+	lockdep_init_map_wait(&(l)->dep_map, #l, &__key, 0, LD_WAIT_CONFIG);\
 } while (0)
+#endif
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#ifdef CONFIG_PREEMPT_RT
+
+static inline void local_lock_acquire(local_lock_t *l)
+{
+	if (l->owner != current) {
+		spin_lock(&l->lock);
+		DEBUG_LOCKS_WARN_ON(l->owner);
+		DEBUG_LOCKS_WARN_ON(l->nestcnt);
+		l->owner = current;
+	}
+	l->nestcnt++;
+}
+
+static inline void local_lock_release(local_lock_t *l)
+{
+	DEBUG_LOCKS_WARN_ON(l->nestcnt == 0);
+	DEBUG_LOCKS_WARN_ON(l->owner != current);
+	if (--l->nestcnt)
+		return;
+
+	l->owner = NULL;
+	spin_unlock(&l->lock);
+}
+
+#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
 static inline void local_lock_acquire(local_lock_t *l)
 {
 	lock_map_acquire(&l->dep_map);
@@ -55,10 +112,45 @@ static inline void local_lock_release(local_lock_t *l) { }
 
 #define __local_lock(lock)					\
 	do {							\
-		preempt_disable();				\
+		migrate_disable();				\
 		local_lock_acquire(this_cpu_ptr(lock));		\
 	} while (0)
 
+#define __local_unlock(lock)					\
+	do {							\
+		local_lock_release(this_cpu_ptr(lock));		\
+		migrate_enable();				\
+	} while (0)
+
+#ifdef CONFIG_PREEMPT_RT
+
+#define __local_lock_irq(lock)					\
+	do {							\
+		migrate_disable();				\
+		local_lock_acquire(this_cpu_ptr(lock));		\
+	} while (0)
+
+#define __local_lock_irqsave(lock, flags)			\
+	do {							\
+		migrate_disable();				\
+		flags = 0;					\
+		local_lock_acquire(this_cpu_ptr(lock));		\
+	} while (0)
+
+#define __local_unlock_irq(lock)				\
+	do {							\
+		local_lock_release(this_cpu_ptr(lock));		\
+		migrate_enable();				\
+	} while (0)
+
+#define __local_unlock_irqrestore(lock, flags)			\
+	do {							\
+		local_lock_release(this_cpu_ptr(lock));		\
+		migrate_enable();				\
+	} while (0)
+
+#else
+
 #define __local_lock_irq(lock)					\
 	do {							\
 		local_irq_disable();				\
@@ -71,12 +163,6 @@ static inline void local_lock_release(local_lock_t *l) { }
 		local_lock_acquire(this_cpu_ptr(lock));		\
 	} while (0)
 
-#define __local_unlock(lock)					\
-	do {							\
-		local_lock_release(this_cpu_ptr(lock));		\
-		preempt_enable();				\
-	} while (0)
-
 #define __local_unlock_irq(lock)				\
 	do {							\
 		local_lock_release(this_cpu_ptr(lock));		\
@@ -88,3 +174,5 @@ static inline void local_lock_release(local_lock_t *l) { }
 		local_lock_release(this_cpu_ptr(lock));		\
 		local_irq_restore(flags);			\
 	} while (0)
+
+#endif
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 496c3ff97cce7..045645dae0843 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -12,6 +12,7 @@
 #include <linux/completion.h>
 #include <linux/cpumask.h>
 #include <linux/uprobes.h>
+#include <linux/rcupdate.h>
 #include <linux/page-flags-layout.h>
 #include <linux/workqueue.h>
 
@@ -538,6 +539,9 @@ struct mm_struct {
 		bool tlb_flush_batched;
 #endif
 		struct uprobes_state uprobes_state;
+#ifdef CONFIG_PREEMPT_RT
+		struct rcu_head delayed_drop;
+#endif
 #ifdef CONFIG_HUGETLB_PAGE
 		atomic_long_t hugetlb_usage;
 #endif
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index dcd185cbfe793..90f090efcb58d 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -22,6 +22,20 @@
 
 struct ww_acquire_ctx;
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname)			\
+		, .dep_map = {					\
+			.name = #lockname,			\
+			.wait_type_inner = LD_WAIT_SLEEP,	\
+		}
+#else
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/mutex_rt.h>
+#else
+
 /*
  * Simple, straightforward mutexes with strict semantics:
  *
@@ -68,14 +82,6 @@ struct mutex {
 struct ww_class;
 struct ww_acquire_ctx;
 
-struct ww_mutex {
-	struct mutex base;
-	struct ww_acquire_ctx *ctx;
-#ifdef CONFIG_DEBUG_MUTEXES
-	struct ww_class *ww_class;
-#endif
-};
-
 /*
  * This is the control structure for tasks blocked on mutex,
  * which resides on the blocked task's kernel stack:
@@ -119,16 +125,6 @@ do {									\
 	__mutex_init((mutex), #mutex, &__key);				\
 } while (0)
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)			\
-		, .dep_map = {					\
-			.name = #lockname,			\
-			.wait_type_inner = LD_WAIT_SLEEP,	\
-		}
-#else
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
-#endif
-
 #define __MUTEX_INITIALIZER(lockname) \
 		{ .owner = ATOMIC_LONG_INIT(0) \
 		, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
@@ -224,4 +220,6 @@ enum mutex_trylock_recursive_enum {
 extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
 mutex_trylock_recursive(struct mutex *lock);
 
+#endif /* !PREEMPT_RT */
+
 #endif /* __LINUX_MUTEX_H */
diff --git a/include/linux/mutex_rt.h b/include/linux/mutex_rt.h
new file mode 100644
index 0000000000000..3fcb5edb1d2b4
--- /dev/null
+++ b/include/linux/mutex_rt.h
@@ -0,0 +1,130 @@
+#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 void __lockfunc _mutex_lock_io(struct mutex *lock);
+extern void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass);
+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_lock_io(l)		_mutex_lock_io(l);
+
+#define __mutex_owner(l)		((l)->lock.owner)
+
+#ifdef CONFIG_DEBUG_MUTEXES
+#define mutex_destroy(l)		rt_mutex_destroy(&(l)->lock)
+#else
+static inline void mutex_destroy(struct mutex *lock) {}
+#endif
+
+#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_io_nested(l, s)	_mutex_lock_io_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)
+# define mutex_lock_io_nested(l, s)	_mutex_lock_io(l)
+#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)
+
+/**
+ * These values are chosen such that FAIL and SUCCESS match the
+ * values of the regular mutex_trylock().
+ */
+enum mutex_trylock_recursive_enum {
+	MUTEX_TRYLOCK_FAILED    = 0,
+	MUTEX_TRYLOCK_SUCCESS   = 1,
+	MUTEX_TRYLOCK_RECURSIVE,
+};
+/**
+ * mutex_trylock_recursive - trylock variant that allows recursive locking
+ * @lock: mutex to be locked
+ *
+ * This function should not be used, _ever_. It is purely for hysterical GEM
+ * raisins, and once those are gone this will be removed.
+ *
+ * Returns:
+ *  MUTEX_TRYLOCK_FAILED    - trylock failed,
+ *  MUTEX_TRYLOCK_SUCCESS   - lock acquired,
+ *  MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
+ */
+int __rt_mutex_owner_current(struct rt_mutex *lock);
+
+static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
+mutex_trylock_recursive(struct mutex *lock)
+{
+	if (unlikely(__rt_mutex_owner_current(&lock->lock)))
+		return MUTEX_TRYLOCK_RECURSIVE;
+
+	return mutex_trylock(lock);
+}
+
+extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
+
+#endif
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 9408f3252c8ee..c49bb4194369b 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1670,7 +1670,7 @@ struct nfs_unlinkdata {
 	struct nfs_removeargs args;
 	struct nfs_removeres res;
 	struct dentry *dentry;
-	wait_queue_head_t wq;
+	struct swait_queue_head wq;
 	const struct cred *cred;
 	struct nfs_fattr dir_attr;
 	long timeout;
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 176d6cf80e7c1..4daecc34c097f 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -3,6 +3,7 @@
 #define _LINUX_PID_H
 
 #include <linux/rculist.h>
+#include <linux/atomic.h>
 #include <linux/wait.h>
 #include <linux/refcount.h>
 
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 7d9c1c0e149c0..d8a401c3a1df3 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -78,10 +78,8 @@
 #include <asm/preempt.h>
 
 #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))
-
 /*
  * Are we doing bottom half or hardware interrupt processing?
  *
@@ -96,12 +94,23 @@
  *       should not be used in new code.
  */
 #define in_irq()		(hardirq_count())
-#define in_softirq()		(softirq_count())
 #define in_interrupt()		(irq_count())
-#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
 #define in_nmi()		(preempt_count() & NMI_MASK)
 #define in_task()		(!(preempt_count() & \
 				   (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))
+#ifdef CONFIG_PREEMPT_RT
+
+#define softirq_count()		((long)current->softirq_count)
+#define in_softirq()		(softirq_count())
+#define in_serving_softirq()	(current->softirq_count & SOFTIRQ_OFFSET)
+
+#else
+
+#define softirq_count()		(preempt_count() & SOFTIRQ_MASK)
+#define in_softirq()		(softirq_count())
+#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
+
+#endif
 
 /*
  * The preempt_count offset after preempt_disable();
@@ -115,7 +124,11 @@
 /*
  * The preempt_count offset after spin_lock()
  */
+#if !defined(CONFIG_PREEMPT_RT)
 #define PREEMPT_LOCK_OFFSET	PREEMPT_DISABLE_OFFSET
+#else
+#define PREEMPT_LOCK_OFFSET	0
+#endif
 
 /*
  * The preempt_count offset needed for things like:
@@ -164,6 +177,20 @@ extern void preempt_count_sub(int val);
 #define preempt_count_inc() preempt_count_add(1)
 #define preempt_count_dec() preempt_count_sub(1)
 
+#ifdef CONFIG_PREEMPT_LAZY
+#define add_preempt_lazy_count(val)	do { preempt_lazy_count() += (val); } while (0)
+#define sub_preempt_lazy_count(val)	do { preempt_lazy_count() -= (val); } while (0)
+#define inc_preempt_lazy_count()	add_preempt_lazy_count(1)
+#define dec_preempt_lazy_count()	sub_preempt_lazy_count(1)
+#define preempt_lazy_count()		(current_thread_info()->preempt_lazy_count)
+#else
+#define add_preempt_lazy_count(val)	do { } while (0)
+#define sub_preempt_lazy_count(val)	do { } while (0)
+#define inc_preempt_lazy_count()	do { } while (0)
+#define dec_preempt_lazy_count()	do { } while (0)
+#define preempt_lazy_count()		(0)
+#endif
+
 #ifdef CONFIG_PREEMPT_COUNT
 
 #define preempt_disable() \
@@ -172,13 +199,25 @@ do { \
 	barrier(); \
 } while (0)
 
+#define preempt_lazy_disable() \
+do { \
+	inc_preempt_lazy_count(); \
+	barrier(); \
+} while (0)
+
 #define sched_preempt_enable_no_resched() \
 do { \
 	barrier(); \
 	preempt_count_dec(); \
 } while (0)
 
-#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+#ifdef CONFIG_PREEMPT_RT
+# define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+# define preempt_check_resched_rt() preempt_check_resched()
+#else
+# define preempt_enable_no_resched() preempt_enable()
+# define preempt_check_resched_rt() barrier();
+#endif
 
 #define preemptible()	(preempt_count() == 0 && !irqs_disabled())
 
@@ -203,6 +242,13 @@ do { \
 		__preempt_schedule(); \
 } while (0)
 
+#define preempt_lazy_enable() \
+do { \
+	dec_preempt_lazy_count(); \
+	barrier(); \
+	preempt_check_resched(); \
+} while (0)
+
 #else /* !CONFIG_PREEMPTION */
 #define preempt_enable() \
 do { \
@@ -210,6 +256,12 @@ do { \
 	preempt_count_dec(); \
 } while (0)
 
+#define preempt_lazy_enable() \
+do { \
+	dec_preempt_lazy_count(); \
+	barrier(); \
+} while (0)
+
 #define preempt_enable_notrace() \
 do { \
 	barrier(); \
@@ -248,6 +300,7 @@ do { \
 #define preempt_disable_notrace()		barrier()
 #define preempt_enable_no_resched_notrace()	barrier()
 #define preempt_enable_notrace()		barrier()
+#define preempt_check_resched_rt()		barrier()
 #define preemptible()				0
 
 #endif /* CONFIG_PREEMPT_COUNT */
@@ -268,10 +321,22 @@ do { \
 } while (0)
 #define preempt_fold_need_resched() \
 do { \
-	if (tif_need_resched()) \
+	if (tif_need_resched_now()) \
 		set_preempt_need_resched(); \
 } while (0)
 
+#ifdef CONFIG_PREEMPT_RT
+# define preempt_disable_rt()		preempt_disable()
+# define preempt_enable_rt()		preempt_enable()
+# define preempt_disable_nort()		barrier()
+# define preempt_enable_nort()		barrier()
+#else
+# define preempt_disable_rt()		barrier()
+# define preempt_enable_rt()		barrier()
+# define preempt_disable_nort()		preempt_disable()
+# define preempt_enable_nort()		preempt_enable()
+#endif
+
 #ifdef CONFIG_PREEMPT_NOTIFIERS
 
 struct preempt_notifier;
@@ -322,6 +387,23 @@ static inline void preempt_notifier_init(struct preempt_notifier *notifier,
 
 #endif
 
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+
+int __migrate_disabled(struct task_struct *p);
+
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+static inline int __migrate_disabled(struct task_struct *p)
+{
+	return 0;
+}
+
+#else
 /**
  * migrate_disable - Prevent migration of the current task
  *
@@ -352,4 +434,9 @@ static __always_inline void migrate_enable(void)
 	preempt_enable();
 }
 
+static inline int __migrate_disabled(struct task_struct *p)
+{
+	return 0;
+}
+#endif
 #endif /* __LINUX_PREEMPT_H */
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 34c1a7be3e014..4318e2190408a 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -59,6 +59,7 @@ static inline const char *printk_skip_headers(const char *buffer)
  */
 #define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT
 #define CONSOLE_LOGLEVEL_QUIET	 CONFIG_CONSOLE_LOGLEVEL_QUIET
+#define CONSOLE_LOGLEVEL_EMERGENCY CONFIG_CONSOLE_LOGLEVEL_EMERGENCY
 
 extern int console_printk[];
 
@@ -66,6 +67,7 @@ extern int console_printk[];
 #define default_message_loglevel (console_printk[1])
 #define minimum_console_loglevel (console_printk[2])
 #define default_console_loglevel (console_printk[3])
+#define emergency_console_loglevel (console_printk[4])
 
 static inline void console_silent(void)
 {
@@ -147,18 +149,6 @@ static inline __printf(1, 2) __cold
 void early_printk(const char *s, ...) { }
 #endif
 
-#ifdef CONFIG_PRINTK_NMI
-extern void printk_nmi_enter(void);
-extern void printk_nmi_exit(void);
-extern void printk_nmi_direct_enter(void);
-extern void printk_nmi_direct_exit(void);
-#else
-static inline void printk_nmi_enter(void) { }
-static inline void printk_nmi_exit(void) { }
-static inline void printk_nmi_direct_enter(void) { }
-static inline void printk_nmi_direct_exit(void) { }
-#endif /* PRINTK_NMI */
-
 #ifdef CONFIG_PRINTK
 asmlinkage __printf(5, 0)
 int vprintk_emit(int facility, int level,
@@ -203,8 +193,7 @@ __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
 void dump_stack_print_info(const char *log_lvl);
 void show_regs_print_info(const char *log_lvl);
 extern asmlinkage void dump_stack(void) __cold;
-extern void printk_safe_flush(void);
-extern void printk_safe_flush_on_panic(void);
+struct wait_queue_head *printk_wait_queue(void);
 #else
 static inline __printf(1, 0)
 int vprintk(const char *s, va_list args)
@@ -269,13 +258,6 @@ static inline void dump_stack(void)
 {
 }
 
-static inline void printk_safe_flush(void)
-{
-}
-
-static inline void printk_safe_flush_on_panic(void)
-{
-}
 #endif
 
 extern int kptr_restrict;
diff --git a/include/linux/printk_ringbuffer.h b/include/linux/printk_ringbuffer.h
new file mode 100644
index 0000000000000..afd03305d2066
--- /dev/null
+++ b/include/linux/printk_ringbuffer.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PRINTK_RINGBUFFER_H
+#define _LINUX_PRINTK_RINGBUFFER_H
+
+#include <linux/irq_work.h>
+#include <linux/atomic.h>
+#include <linux/percpu.h>
+#include <linux/wait.h>
+
+struct prb_cpulock {
+	atomic_t owner;
+	unsigned long __percpu *irqflags;
+};
+
+struct printk_ringbuffer {
+	void *buffer;
+	unsigned int size_bits;
+
+	u64 seq;
+	atomic_long_t lost;
+
+	atomic_long_t tail;
+	atomic_long_t head;
+	atomic_long_t reserve;
+
+	struct prb_cpulock *cpulock;
+	atomic_t ctx;
+
+	struct wait_queue_head *wq;
+	atomic_long_t wq_counter;
+	struct irq_work *wq_work;
+};
+
+struct prb_entry {
+	unsigned int size;
+	u64 seq;
+	char data[0];
+};
+
+struct prb_handle {
+	struct printk_ringbuffer *rb;
+	unsigned int cpu;
+	struct prb_entry *entry;
+};
+
+#define DECLARE_STATIC_PRINTKRB_CPULOCK(name)				\
+static DEFINE_PER_CPU(unsigned long, _##name##_percpu_irqflags);	\
+static struct prb_cpulock name = {					\
+	.owner = ATOMIC_INIT(-1),					\
+	.irqflags = &_##name##_percpu_irqflags,				\
+}
+
+#define PRB_INIT ((unsigned long)-1)
+
+#define DECLARE_STATIC_PRINTKRB_ITER(name, rbaddr)			\
+static struct prb_iterator name = {					\
+	.rb = rbaddr,							\
+	.lpos = PRB_INIT,						\
+}
+
+struct prb_iterator {
+	struct printk_ringbuffer *rb;
+	unsigned long lpos;
+};
+
+#define DECLARE_STATIC_PRINTKRB(name, szbits, cpulockptr)		\
+static char _##name##_buffer[1 << (szbits)]				\
+	__aligned(__alignof__(long));					\
+static DECLARE_WAIT_QUEUE_HEAD(_##name##_wait);				\
+static void _##name##_wake_work_func(struct irq_work *irq_work)		\
+{									\
+	wake_up_interruptible_all(&_##name##_wait);			\
+}									\
+static struct irq_work _##name##_wake_work = {				\
+	.func = _##name##_wake_work_func,				\
+	.flags = ATOMIC_INIT(IRQ_WORK_LAZY),				\
+};									\
+static struct printk_ringbuffer name = {				\
+	.buffer = &_##name##_buffer[0],					\
+	.size_bits = szbits,						\
+	.seq = 0,							\
+	.lost = ATOMIC_LONG_INIT(0),					\
+	.tail = ATOMIC_LONG_INIT(-111 * sizeof(long)),			\
+	.head = ATOMIC_LONG_INIT(-111 * sizeof(long)),			\
+	.reserve = ATOMIC_LONG_INIT(-111 * sizeof(long)),		\
+	.cpulock = cpulockptr,						\
+	.ctx = ATOMIC_INIT(0),						\
+	.wq = &_##name##_wait,						\
+	.wq_counter = ATOMIC_LONG_INIT(0),				\
+	.wq_work = &_##name##_wake_work,				\
+}
+
+/* writer interface */
+char *prb_reserve(struct prb_handle *h, struct printk_ringbuffer *rb,
+		  unsigned int size);
+void prb_commit(struct prb_handle *h);
+
+/* reader interface */
+void prb_iter_init(struct prb_iterator *iter, struct printk_ringbuffer *rb,
+		   u64 *seq);
+void prb_iter_copy(struct prb_iterator *dest, struct prb_iterator *src);
+int prb_iter_next(struct prb_iterator *iter, char *buf, int size, u64 *seq);
+int prb_iter_wait_next(struct prb_iterator *iter, char *buf, int size,
+		       u64 *seq);
+int prb_iter_seek(struct prb_iterator *iter, u64 seq);
+int prb_iter_data(struct prb_iterator *iter, char *buf, int size, u64 *seq);
+
+/* utility functions */
+int prb_buffer_size(struct printk_ringbuffer *rb);
+void prb_inc_lost(struct printk_ringbuffer *rb);
+void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+void prb_unlock(struct prb_cpulock *cpu_lock, unsigned int cpu_store);
+
+#endif /*_LINUX_PRINTK_RINGBUFFER_H */
diff --git a/include/linux/random.h b/include/linux/random.h
index f45b8be3e3c4e..0e41d05278091 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -35,7 +35,7 @@ static inline void add_latent_entropy(void) {}
 
 extern void add_input_randomness(unsigned int type, unsigned int code,
 				 unsigned int value) __latent_entropy;
-extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
+extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) __latent_entropy;
 
 extern void get_random_bytes(void *buf, int nbytes);
 extern int wait_for_random_bytes(void);
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
index b17e0cd0a30cf..5ca206a41d678 100644
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -28,7 +28,7 @@ static inline void ratelimit_state_exit(struct ratelimit_state *rs)
 		return;
 
 	if (rs->missed) {
-		pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
+		pr_info("%s: %d output lines suppressed due to ratelimiting\n",
 			current->comm, rs->missed);
 		rs->missed = 0;
 	}
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index d7db179963221..c33b0e16d04b4 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -19,19 +19,9 @@
 
 #include <linux/kernel.h>
 #include <linux/stddef.h>
+#include <linux/rbtree_type.h>
 #include <linux/rcupdate.h>
 
-struct rb_node {
-	unsigned long  __rb_parent_color;
-	struct rb_node *rb_right;
-	struct rb_node *rb_left;
-} __attribute__((aligned(sizeof(long))));
-    /* The alignment might seem pointless, but allegedly CRIS needs it */
-
-struct rb_root {
-	struct rb_node *rb_node;
-};
-
 #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
 
 #define RB_ROOT	(struct rb_root) { NULL, }
@@ -112,21 +102,6 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent
 			typeof(*pos), field); 1; }); \
 	     pos = n)
 
-/*
- * Leftmost-cached rbtrees.
- *
- * We do not cache the rightmost node based on footprint
- * size vs number of potential users that could benefit
- * from O(1) rb_last(). Just not worth it, users that want
- * this feature can always implement the logic explicitly.
- * Furthermore, users that want to cache both pointers may
- * find it a bit asymmetric, but that's ok.
- */
-struct rb_root_cached {
-	struct rb_root rb_root;
-	struct rb_node *rb_leftmost;
-};
-
 #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
 
 /* Same as rb_first(), but O(1) */
diff --git a/include/linux/rbtree_type.h b/include/linux/rbtree_type.h
new file mode 100644
index 0000000000000..77a89dd2c7c66
--- /dev/null
+++ b/include/linux/rbtree_type.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _LINUX_RBTREE_TYPE_H
+#define _LINUX_RBTREE_TYPE_H
+
+struct rb_node {
+	unsigned long  __rb_parent_color;
+	struct rb_node *rb_right;
+	struct rb_node *rb_left;
+} __attribute__((aligned(sizeof(long))));
+/* The alignment might seem pointless, but allegedly CRIS needs it */
+
+struct rb_root {
+	struct rb_node *rb_node;
+};
+
+/*
+ * Leftmost-cached rbtrees.
+ *
+ * We do not cache the rightmost node based on footprint
+ * size vs number of potential users that could benefit
+ * from O(1) rb_last(). Just not worth it, users that want
+ * this feature can always implement the logic explicitly.
+ * Furthermore, users that want to cache both pointers may
+ * find it a bit asymmetric, but that's ok.
+ */
+struct rb_root_cached {
+	struct rb_root rb_root;
+	struct rb_node *rb_leftmost;
+};
+
+#endif
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d15d46db61f75..2b594bfb520dd 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -52,6 +52,11 @@ void __rcu_read_unlock(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
+#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 */
 
@@ -70,6 +75,8 @@ 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 */
@@ -312,7 +319,8 @@ static inline void rcu_preempt_sleep_check(void) { }
 #define rcu_sleep_check()						\
 	do {								\
 		rcu_preempt_sleep_check();				\
-		RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT))		\
+		    RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
 				 "Illegal context switch in RCU-bh read-side critical section"); \
 		RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),	\
 				 "Illegal context switch in RCU-sched read-side critical section"); \
diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 6fd615a0eea94..46b266d3ed2e8 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -14,11 +14,15 @@
 #define __LINUX_RT_MUTEX_H
 
 #include <linux/linkage.h>
-#include <linux/rbtree.h>
-#include <linux/spinlock_types.h>
+#include <linux/rbtree_type.h>
+#include <linux/spinlock_types_raw.h>
 
 extern int max_lock_depth; /* for sysctl */
 
+#ifdef CONFIG_DEBUG_MUTEXES
+#include <linux/debug_locks.h>
+#endif
+
 /**
  * The rt_mutex structure
  *
@@ -31,8 +35,8 @@ struct rt_mutex {
 	raw_spinlock_t		wait_lock;
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
 	int			save_state;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
 	const char		*name, *file;
 	int			line;
 	void			*magic;
@@ -82,16 +86,23 @@ do { \
 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
 #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) \
 	, .waiters = RB_ROOT_CACHED \
 	, .owner = NULL \
 	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
+	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
+
+#define __RT_MUTEX_INITIALIZER(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname) }
 
 #define DEFINE_RT_MUTEX(mutexname) \
 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
 
+#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname)    \
+		, .save_state = 1 }
+
 /**
  * rt_mutex_is_locked - is the mutex locked
  * @lock: the mutex to be queried
@@ -115,6 +126,7 @@ extern void rt_mutex_lock(struct rt_mutex *lock);
 #endif
 
 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock);
 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
 			       struct hrtimer_sleeper *timeout);
 
diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h
new file mode 100644
index 0000000000000..a9c4c2ac4d1fa
--- /dev/null
+++ b/include/linux/rwlock_rt.h
@@ -0,0 +1,119 @@
+#ifndef __LINUX_RWLOCK_RT_H
+#define __LINUX_RWLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+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_read_trylock(rwlock_t *rwlock);
+extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
+extern int __lockfunc rt_read_can_lock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_can_lock(rwlock_t *rwlock);
+extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
+
+#define read_can_lock(rwlock)		rt_read_can_lock(rwlock)
+#define write_can_lock(rwlock)		rt_write_can_lock(rwlock)
+
+#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
+#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
+
+static inline int __write_trylock_rt_irqsave(rwlock_t *lock, unsigned long *flags)
+{
+	/* XXX ARCH_IRQ_ENABLED */
+	*flags = 0;
+	return rt_write_trylock(lock);
+}
+
+#define write_trylock_irqsave(lock, flags)		\
+	__cond_lock(lock, __write_trylock_rt_irqsave(lock, &(flags)))
+
+#define read_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		rt_read_lock(lock);			\
+		flags = 0;				\
+	} while (0)
+
+#define write_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		rt_write_lock(lock);			\
+		flags = 0;				\
+	} while (0)
+
+#define read_lock(lock)		rt_read_lock(lock)
+
+#define read_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		rt_read_lock(lock);			\
+	} while (0)
+
+#define read_lock_irq(lock)	read_lock(lock)
+
+#define write_lock(lock)	rt_write_lock(lock)
+
+#define write_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		rt_write_lock(lock);			\
+	} while (0)
+
+#define write_lock_irq(lock)	write_lock(lock)
+
+#define read_unlock(lock)	rt_read_unlock(lock)
+
+#define read_unlock_bh(lock)				\
+	do {						\
+		rt_read_unlock(lock);			\
+		local_bh_enable();			\
+	} while (0)
+
+#define read_unlock_irq(lock)	read_unlock(lock)
+
+#define write_unlock(lock)	rt_write_unlock(lock)
+
+#define write_unlock_bh(lock)				\
+	do {						\
+		rt_write_unlock(lock);			\
+		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);			\
+	} while (0)
+
+#define write_unlock_irqrestore(lock, flags) \
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		rt_write_unlock(lock);			\
+	} while (0)
+
+#define rwlock_init(rwl)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	__rt_rwlock_init(rwl, #rwl, &__key);		\
+} while (0)
+
+/*
+ * Internal functions made global for CPU pinning
+ */
+void __read_rt_lock(struct rt_rw_lock *lock);
+int __read_rt_trylock(struct rt_rw_lock *lock);
+void __write_rt_lock(struct rt_rw_lock *lock);
+int __write_rt_trylock(struct rt_rw_lock *lock);
+void __read_rt_unlock(struct rt_rw_lock *lock);
+void __write_rt_unlock(struct rt_rw_lock *lock);
+
+#endif
diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h
index 3bd03e18061c1..0ad226b5d8fd5 100644
--- a/include/linux/rwlock_types.h
+++ b/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
diff --git a/include/linux/rwlock_types_rt.h b/include/linux/rwlock_types_rt.h
new file mode 100644
index 0000000000000..546a1f8f12748
--- /dev/null
+++ b/include/linux/rwlock_types_rt.h
@@ -0,0 +1,55 @@
+#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
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define RW_DEP_MAP_INIT(lockname)
+#endif
+
+typedef struct rt_rw_lock rwlock_t;
+
+#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name)
+
+#define DEFINE_RWLOCK(name) \
+	rwlock_t name = __RW_LOCK_UNLOCKED(name)
+
+/*
+ * A reader biased implementation primarily for CPU pinning.
+ *
+ * Can be selected as general replacement for the single reader RT rwlock
+ * variant
+ */
+struct rt_rw_lock {
+	struct rt_mutex		rtmutex;
+	atomic_t		readers;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define READER_BIAS	(1U << 31)
+#define WRITER_BIAS	(1U << 30)
+
+#define __RWLOCK_RT_INITIALIZER(name)					\
+{									\
+	.readers = ATOMIC_INIT(READER_BIAS),				\
+	.rtmutex = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.rtmutex),	\
+	RW_DEP_MAP_INIT(name)						\
+}
+
+void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
+			     struct lock_class_key *key);
+
+#define rwlock_biased_rt_init(rwlock)					\
+	do {								\
+		static struct lock_class_key __key;			\
+									\
+		__rwlock_biased_rt_init((rwlock), #rwlock, &__key);	\
+	} while (0)
+
+#endif
diff --git a/include/linux/rwsem-rt.h b/include/linux/rwsem-rt.h
new file mode 100644
index 0000000000000..2018ff77904ad
--- /dev/null
+++ b/include/linux/rwsem-rt.h
@@ -0,0 +1,68 @@
+#ifndef _LINUX_RWSEM_RT_H
+#define _LINUX_RWSEM_RT_H
+
+#ifndef _LINUX_RWSEM_H
+#error "Include rwsem.h"
+#endif
+
+#include <linux/rtmutex.h>
+#include <linux/swait.h>
+
+#define READER_BIAS		(1U << 31)
+#define WRITER_BIAS		(1U << 30)
+
+struct rw_semaphore {
+	atomic_t		readers;
+	struct rt_mutex		rtmutex;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define __RWSEM_INITIALIZER(name)				\
+{								\
+	.readers = ATOMIC_INIT(READER_BIAS),			\
+	.rtmutex = __RT_MUTEX_INITIALIZER(name.rtmutex),	\
+	RW_DEP_MAP_INIT(name)					\
+}
+
+#define DECLARE_RWSEM(lockname) \
+	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
+
+extern void  __rwsem_init(struct rw_semaphore *rwsem, const char *name,
+			  struct lock_class_key *key);
+
+#define __init_rwsem(sem, name, key)			\
+do {							\
+		rt_mutex_init(&(sem)->rtmutex);		\
+		__rwsem_init((sem), (name), (key));	\
+} while (0)
+
+#define init_rwsem(sem)					\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	__init_rwsem((sem), #sem, &__key);		\
+} while (0)
+
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return atomic_read(&sem->readers) != READER_BIAS;
+}
+
+static inline int rwsem_is_contended(struct rw_semaphore *sem)
+{
+	return atomic_read(&sem->readers) > 0;
+}
+
+extern void __down_read(struct rw_semaphore *sem);
+extern int __down_read_killable(struct rw_semaphore *sem);
+extern int __down_read_trylock(struct rw_semaphore *sem);
+extern void __down_write(struct rw_semaphore *sem);
+extern int __must_check __down_write_killable(struct rw_semaphore *sem);
+extern int __down_write_trylock(struct rw_semaphore *sem);
+extern void __up_read(struct rw_semaphore *sem);
+extern void __up_write(struct rw_semaphore *sem);
+extern void __downgrade_write(struct rw_semaphore *sem);
+
+#endif
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 25e3fde856178..9101367852bc9 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -16,6 +16,11 @@
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
 #include <linux/err.h>
+
+#ifdef CONFIG_PREEMPT_RT
+#include <linux/rwsem-rt.h>
+#else /* PREEMPT_RT */
+
 #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
 #include <linux/osq_lock.h>
 #endif
@@ -119,6 +124,13 @@ static inline int rwsem_is_contended(struct rw_semaphore *sem)
 	return !list_empty(&sem->wait_list);
 }
 
+#endif /* !PREEMPT_RT */
+
+/*
+ * The functions below are the same for all rwsem implementations including
+ * the RT specific variant.
+ */
+
 /*
  * lock for reading
  */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index afe01e232935f..2453d40af7065 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -34,6 +34,7 @@
 #include <linux/rseq.h>
 #include <linux/seqlock.h>
 #include <linux/kcsan.h>
+#include <asm/kmap_types.h>
 
 /* task_struct member predeclarations (sorted alphabetically): */
 struct audit_context;
@@ -110,12 +111,8 @@ struct task_group;
 					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
 					 TASK_PARKED)
 
-#define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
-
 #define task_is_stopped(task)		((task->state & __TASK_STOPPED) != 0)
 
-#define task_is_stopped_or_traced(task)	((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
-
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 
 /*
@@ -139,6 +136,9 @@ struct task_group;
 		smp_store_mb(current->state, (state_value));	\
 	} while (0)
 
+#define __set_current_state_no_track(state_value)		\
+	current->state = (state_value);
+
 #define set_special_state(state_value)					\
 	do {								\
 		unsigned long flags; /* may shadow */			\
@@ -148,6 +148,7 @@ struct task_group;
 		current->state = (state_value);				\
 		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	\
 	} while (0)
+
 #else
 /*
  * set_current_state() includes a barrier so that the write of current->state
@@ -192,6 +193,9 @@ struct task_group;
 #define set_current_state(state_value)					\
 	smp_store_mb(current->state, (state_value))
 
+#define __set_current_state_no_track(state_value)	\
+	__set_current_state(state_value)
+
 /*
  * set_special_state() should be used for those states when the blocking task
  * can not use the regular condition based wait-loop. In that case we must
@@ -229,6 +233,8 @@ extern void io_schedule_finish(int token);
 extern long io_schedule_timeout(long timeout);
 extern void io_schedule(void);
 
+int cpu_nr_pinned(int cpu);
+
 /**
  * struct prev_cputime - snapshot of system and user cputime
  * @utime: time spent in user mode
@@ -638,6 +644,8 @@ struct task_struct {
 #endif
 	/* -1 unrunnable, 0 runnable, >0 stopped: */
 	volatile long			state;
+	/* saved state for "spinlock sleepers" */
+	volatile long			saved_state;
 
 	/*
 	 * This begins the randomizable portion of task_struct. Only
@@ -713,6 +721,20 @@ struct task_struct {
 	int				nr_cpus_allowed;
 	const cpumask_t			*cpus_ptr;
 	cpumask_t			cpus_mask;
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+	int				migrate_disable;
+	bool				migrate_disable_scheduled;
+# ifdef CONFIG_SCHED_DEBUG
+	int				pinned_on_cpu;
+# endif
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+# ifdef CONFIG_SCHED_DEBUG
+	int				migrate_disable;
+# endif
+#endif
+#ifdef CONFIG_PREEMPT_RT
+	int				sleeping_lock;
+#endif
 
 #ifdef CONFIG_PREEMPT_RCU
 	int				rcu_read_lock_nesting;
@@ -941,11 +963,16 @@ struct task_struct {
 	/* Signal handlers: */
 	struct signal_struct		*signal;
 	struct sighand_struct __rcu		*sighand;
+	struct sigqueue			*sigqueue_cache;
 	sigset_t			blocked;
 	sigset_t			real_blocked;
 	/* Restored if set_restore_sigmask() was used: */
 	sigset_t			saved_sigmask;
 	struct sigpending		pending;
+#ifdef CONFIG_PREEMPT_RT
+	/* TODO: move me into ->restart_block ? */
+	struct				kernel_siginfo forced_info;
+#endif
 	unsigned long			sas_ss_sp;
 	size_t				sas_ss_size;
 	unsigned int			sas_ss_flags;
@@ -972,6 +999,7 @@ struct task_struct {
 	raw_spinlock_t			pi_lock;
 
 	struct wake_q_node		wake_q;
+	struct wake_q_node		wake_q_sleeper;
 
 #ifdef CONFIG_RT_MUTEXES
 	/* PI waiters blocked on a rt_mutex held by this task: */
@@ -999,6 +1027,9 @@ struct task_struct {
 	int				softirq_context;
 	int				irq_config;
 #endif
+#ifdef CONFIG_PREEMPT_RT
+	int				softirq_count;
+#endif
 
 #ifdef CONFIG_LOCKDEP
 # define MAX_LOCK_DEPTH			48UL
@@ -1280,6 +1311,12 @@ struct task_struct {
 	unsigned int			sequential_io;
 	unsigned int			sequential_io_avg;
 #endif
+#ifdef CONFIG_PREEMPT_RT
+# if defined CONFIG_HIGHMEM || defined CONFIG_X86_32
+	int				kmap_idx;
+	pte_t				kmap_pte[KM_TYPE_NR];
+# endif
+#endif
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 	unsigned long			task_state_change;
 #endif
@@ -1722,6 +1759,7 @@ extern struct task_struct *find_get_task_by_vpid(pid_t nr);
 
 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
@@ -1812,6 +1850,89 @@ static inline int test_tsk_need_resched(struct task_struct *tsk)
 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+static inline void set_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int test_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY));
+}
+
+static inline int need_resched_lazy(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+#else
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { }
+static inline int need_resched_lazy(void) { return 0; }
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+#endif
+
+
+static inline bool __task_is_stopped_or_traced(struct task_struct *task)
+{
+	if (task->state & (__TASK_STOPPED | __TASK_TRACED))
+		return true;
+#ifdef CONFIG_PREEMPT_RT
+	if (task->saved_state & (__TASK_STOPPED | __TASK_TRACED))
+		return true;
+#endif
+	return false;
+}
+
+static inline bool task_is_stopped_or_traced(struct task_struct *task)
+{
+	bool traced_stopped;
+
+#ifdef CONFIG_PREEMPT_RT
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	traced_stopped = __task_is_stopped_or_traced(task);
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+#else
+	traced_stopped = __task_is_stopped_or_traced(task);
+#endif
+	return traced_stopped;
+}
+
+static inline bool task_is_traced(struct task_struct *task)
+{
+	bool traced = false;
+
+	if (task->state & __TASK_TRACED)
+		return true;
+#ifdef CONFIG_PREEMPT_RT
+	/* in case the task is sleeping on tasklist_lock */
+	raw_spin_lock_irq(&task->pi_lock);
+	if (task->state & __TASK_TRACED)
+		traced = true;
+	else if (task->saved_state & __TASK_TRACED)
+		traced = true;
+	raw_spin_unlock_irq(&task->pi_lock);
+#endif
+	return traced;
+}
+
 /*
  * cond_resched() and cond_resched_lock(): latency reduction via
  * explicit rescheduling in places that are safe. The return
@@ -1864,6 +1985,23 @@ static __always_inline bool need_resched(void)
 	return unlikely(tif_need_resched());
 }
 
+#ifdef CONFIG_PREEMPT_RT
+static inline void sleeping_lock_inc(void)
+{
+	current->sleeping_lock++;
+}
+
+static inline void sleeping_lock_dec(void)
+{
+	current->sleeping_lock--;
+}
+
+#else
+
+static inline void sleeping_lock_inc(void) { }
+static inline void sleeping_lock_dec(void) { }
+#endif
+
 /*
  * Wrappers for p->thread_info->cpu access. No-op on UP.
  */
@@ -2048,4 +2186,6 @@ int sched_trace_rq_nr_running(struct rq *rq);
 
 const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
 
+extern struct task_struct *takedown_cpu_task;
+
 #endif
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index f889e332912fb..1a08d3d41805c 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -49,6 +49,17 @@ static inline void mmdrop(struct mm_struct *mm)
 		__mmdrop(mm);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+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
+
 /*
  * This has to be called after a get_task_mm()/mmget_not_zero()
  * followed by taking the mmap_lock for writing before modifying the
diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h
index 26a2013ac39c4..6e2dff721547c 100644
--- a/include/linux/sched/wake_q.h
+++ b/include/linux/sched/wake_q.h
@@ -58,6 +58,17 @@ static inline bool wake_q_empty(struct wake_q_head *head)
 
 extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
 extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
-extern void wake_up_q(struct wake_q_head *head);
+extern void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task);
+extern void __wake_up_q(struct wake_q_head *head, bool sleeper);
+
+static inline void wake_up_q(struct wake_q_head *head)
+{
+	__wake_up_q(head, false);
+}
+
+static inline void wake_up_q_sleeper(struct wake_q_head *head)
+{
+	__wake_up_q(head, true);
+}
 
 #endif /* _LINUX_SCHED_WAKE_Q_H */
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 962d9768945f0..75e3a73e27567 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -17,6 +17,7 @@
 #include <linux/kcsan-checks.h>
 #include <linux/lockdep.h>
 #include <linux/mutex.h>
+#include <linux/ww_mutex.h>
 #include <linux/preempt.h>
 #include <linux/spinlock.h>
 
@@ -131,63 +132,105 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
  * See Documentation/locking/seqlock.rst
  */
 
-#ifdef CONFIG_LOCKDEP
+/*
+ * For PREEMPT_RT, seqcount_LOCKTYPE_t write side critical sections cannot
+ * disable preemption. It can lead to higher latencies and the write side
+ * sections will not be able to acquire locks which become sleeping locks
+ * in RT (e.g. spinlock_t).
+ *
+ * To remain preemptible while avoiding a possible livelock caused by a
+ * reader preempting the write section, use a different technique: detect
+ * if a seqcount_LOCKTYPE_t writer is in progress. If that is the case,
+ * acquire then release the associated LOCKTYPE writer serialization
+ * lock. This will force any possibly preempted writer to make progress
+ * until the end of its writer serialization lock critical section.
+ *
+ * This lock-unlock technique must be implemented for all PREEMPT_RT
+ * sleeping locks.  See Documentation/locking/locktypes.rst
+ */
+#if defined(CONFIG_LOCKDEP) || defined(CONFIG_PREEMPT_RT)
 #define __SEQ_LOCK(expr)	expr
 #else
 #define __SEQ_LOCK(expr)
 #endif
 
 /**
- * typedef seqcount_LOCKNAME_t - sequence counter with LOCKTYPR associated
+ * typedef seqcount_LOCKTYPE_t - sequence counter with associated lock
  * @seqcount:	The real sequence counter
  * @lock:	Pointer to the associated spinlock
  *
- * A plain sequence counter with external writer synchronization by a
- * spinlock. The spinlock is associated to the sequence count in the
+ * A plain sequence counter with external writer synchronization by
+ * LOCKTYPE @lock. The lock is associated to the sequence counter in the
  * static initializer or init function. This enables lockdep to validate
  * that the write side critical section is properly serialized.
+ *
+ * LOCKTYPE:	raw_spinlock, spinlock, rwlock, mutex, or ww_mutex.
  */
 
 /**
- * seqcount_LOCKNAME_init() - runtime initializer for seqcount_LOCKNAME_t
- * @s:		Pointer to the seqcount_LOCKNAME_t instance
+ * seqcount_LOCKTYPE_init() - runtime initializer for seqcount_LOCKTYPE_t
+ * @s:		Pointer to the seqcount_LOCKTYPE_t instance
  * @lock:	Pointer to the associated LOCKTYPE
  */
 
 /*
- * SEQCOUNT_LOCKTYPE() - Instantiate seqcount_LOCKNAME_t and helpers
- * @locktype:		actual typename
- * @lockname:		name
+ * SEQCOUNT_LOCKTYPE() - Instantiate seqcount_LOCKTYPE_t and helpers
+ * @locktype:		"LOCKTYPE" part of seqcount_LOCKTYPE_t
+ * @locktype_t:		canonical/full LOCKTYPE C data type
  * @preemptible:	preemptibility of above locktype
  * @lockmember:		argument for lockdep_assert_held()
+ * @lockbase:		associated lock release function (prefix only)
+ * @lock_acquire:	associated lock acquisition function (full call)
  */
-#define SEQCOUNT_LOCKTYPE(locktype, lockname, preemptible, lockmember)	\
-typedef struct seqcount_##lockname {					\
+#define SEQCOUNT_LOCKTYPE(locktype, locktype_t, preemptible, lockmember, lockbase, lock_acquire) \
+typedef struct seqcount_##locktype {					\
 	seqcount_t		seqcount;				\
-	__SEQ_LOCK(locktype	*lock);					\
-} seqcount_##lockname##_t;						\
+	__SEQ_LOCK(locktype_t	*lock);					\
+} seqcount_##locktype##_t;						\
 									\
 static __always_inline void						\
-seqcount_##lockname##_init(seqcount_##lockname##_t *s, locktype *lock)	\
+seqcount_##locktype##_init(seqcount_##locktype##_t *s, locktype_t *lock)\
 {									\
 	seqcount_init(&s->seqcount);					\
 	__SEQ_LOCK(s->lock = lock);					\
 }									\
 									\
 static __always_inline seqcount_t *					\
-__seqcount_##lockname##_ptr(seqcount_##lockname##_t *s)			\
+__seqcount_##locktype##_ptr(seqcount_##locktype##_t *s)			\
 {									\
 	return &s->seqcount;						\
 }									\
 									\
+static __always_inline unsigned						\
+__seqcount_##locktype##_sequence(const seqcount_##locktype##_t *s)	\
+{									\
+	unsigned seq = READ_ONCE(s->seqcount.sequence);			\
+									\
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))				\
+		return seq;						\
+									\
+	if (preemptible && unlikely(seq & 1)) {				\
+		__SEQ_LOCK(lock_acquire);				\
+		__SEQ_LOCK(lockbase##_unlock((void *) s->lock));	\
+									\
+		/*							\
+		 * Re-read the sequence counter since the (possibly	\
+		 * preempted) writer made progress.			\
+		 */							\
+		seq = READ_ONCE(s->seqcount.sequence);			\
+	}								\
+									\
+	return seq;							\
+}									\
+									\
 static __always_inline bool						\
-__seqcount_##lockname##_preemptible(seqcount_##lockname##_t *s)		\
+__seqcount_##locktype##_preemptible(seqcount_##locktype##_t *s)		\
 {									\
 	return preemptible;						\
 }									\
 									\
 static __always_inline void						\
-__seqcount_##lockname##_assert(seqcount_##lockname##_t *s)		\
+__seqcount_##locktype##_assert(seqcount_##locktype##_t *s)		\
 {									\
 	__SEQ_LOCK(lockdep_assert_held(lockmember));			\
 }
@@ -196,30 +239,37 @@ __seqcount_##lockname##_assert(seqcount_##lockname##_t *s)		\
  * __seqprop() for seqcount_t
  */
 
-static inline seqcount_t *__seqcount_ptr(seqcount_t *s)
+static inline seqcount_t *__seqcount_t_ptr(seqcount_t *s)
 {
 	return s;
 }
 
-static inline bool __seqcount_preemptible(seqcount_t *s)
+static inline unsigned __seqcount_t_sequence(seqcount_t *s)
+{
+	return READ_ONCE(s->sequence);
+}
+
+static inline bool __seqcount_t_preemptible(seqcount_t *s)
 {
 	return false;
 }
 
-static inline void __seqcount_assert(seqcount_t *s)
+static inline void __seqcount_t_assert(seqcount_t *s)
 {
 	lockdep_assert_preemption_disabled();
 }
 
-SEQCOUNT_LOCKTYPE(raw_spinlock_t,	raw_spinlock,	false,	s->lock)
-SEQCOUNT_LOCKTYPE(spinlock_t,		spinlock,	false,	s->lock)
-SEQCOUNT_LOCKTYPE(rwlock_t,		rwlock,		false,	s->lock)
-SEQCOUNT_LOCKTYPE(struct mutex,		mutex,		true,	s->lock)
-SEQCOUNT_LOCKTYPE(struct ww_mutex,	ww_mutex,	true,	&s->lock->base)
+#define __SEQ_RT	IS_ENABLED(CONFIG_PREEMPT_RT)
+
+SEQCOUNT_LOCKTYPE(raw_spinlock, raw_spinlock_t,  false,    s->lock,        raw_spin, raw_spin_lock(s->lock))
+SEQCOUNT_LOCKTYPE(spinlock,     spinlock_t,      __SEQ_RT, s->lock,        spin,     spin_lock(s->lock))
+SEQCOUNT_LOCKTYPE(rwlock,       rwlock_t,        __SEQ_RT, s->lock,        read,     read_lock(s->lock))
+SEQCOUNT_LOCKTYPE(mutex,        struct mutex,    true,     s->lock,        mutex,    mutex_lock(s->lock))
+SEQCOUNT_LOCKTYPE(ww_mutex,     struct ww_mutex, true,     &s->lock->base, ww_mutex, ww_mutex_lock(s->lock, NULL))
 
 /**
- * SEQCNT_LOCKNAME_ZERO - static initializer for seqcount_LOCKNAME_t
- * @name:	Name of the seqcount_LOCKNAME_t instance
+ * SEQCNT_LOCKTYPE_ZERO - static initializer for seqcount_LOCKTYPE_t
+ * @name:	Name of the seqcount_LOCKTYPE_t instance
  * @lock:	Pointer to the associated LOCKTYPE
  */
 
@@ -234,12 +284,11 @@ SEQCOUNT_LOCKTYPE(struct ww_mutex,	ww_mutex,	true,	&s->lock->base)
 #define SEQCNT_MUTEX_ZERO(name, lock)		SEQCOUNT_LOCKTYPE_ZERO(name, lock)
 #define SEQCNT_WW_MUTEX_ZERO(name, lock) 	SEQCOUNT_LOCKTYPE_ZERO(name, lock)
 
-
-#define __seqprop_case(s, lockname, prop)				\
-	seqcount_##lockname##_t: __seqcount_##lockname##_##prop((void *)(s))
+#define __seqprop_case(s, locktype, prop)				\
+	seqcount_##locktype##_t: __seqcount_##locktype##_##prop((void *)(s))
 
 #define __seqprop(s, prop) _Generic(*(s),				\
-	seqcount_t:		__seqcount_##prop((void *)(s)),		\
+	seqcount_t:		__seqcount_t_##prop((void *)(s)),	\
 	__seqprop_case((s),	raw_spinlock,	prop),			\
 	__seqprop_case((s),	spinlock,	prop),			\
 	__seqprop_case((s),	rwlock,		prop),			\
@@ -247,12 +296,13 @@ SEQCOUNT_LOCKTYPE(struct ww_mutex,	ww_mutex,	true,	&s->lock->base)
 	__seqprop_case((s),	ww_mutex,	prop))
 
 #define __seqcount_ptr(s)		__seqprop(s, ptr)
+#define __seqcount_sequence(s)		__seqprop(s, sequence)
 #define __seqcount_lock_preemptible(s)	__seqprop(s, preemptible)
 #define __seqcount_assert_lock_held(s)	__seqprop(s, assert)
 
 /**
  * __read_seqcount_begin() - begin a seqcount_t read section w/o barrier
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * __read_seqcount_begin is like read_seqcount_begin, but has no smp_rmb()
  * barrier. Callers should ensure that smp_rmb() or equivalent ordering is
@@ -265,56 +315,49 @@ SEQCOUNT_LOCKTYPE(struct ww_mutex,	ww_mutex,	true,	&s->lock->base)
  * Return: count to be passed to read_seqcount_retry()
  */
 #define __read_seqcount_begin(s)					\
-	__read_seqcount_t_begin(__seqcount_ptr(s))
-
-static inline unsigned __read_seqcount_t_begin(const seqcount_t *s)
-{
-	unsigned ret;
-
-repeat:
-	ret = READ_ONCE(s->sequence);
-	if (unlikely(ret & 1)) {
-		cpu_relax();
-		goto repeat;
-	}
-	kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX);
-	return ret;
-}
+({									\
+	unsigned ret;							\
+									\
+	while (true) {							\
+		ret = __seqcount_sequence(s);				\
+		if (likely(! (ret & 1)))				\
+			break;						\
+		cpu_relax();						\
+	}								\
+									\
+	kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX);			\
+	ret;								\
+})
 
 /**
  * raw_read_seqcount_begin() - begin a seqcount_t read section w/o lockdep
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * Return: count to be passed to read_seqcount_retry()
  */
 #define raw_read_seqcount_begin(s)					\
-	raw_read_seqcount_t_begin(__seqcount_ptr(s))
-
-static inline unsigned raw_read_seqcount_t_begin(const seqcount_t *s)
-{
-	unsigned ret = __read_seqcount_t_begin(s);
-	smp_rmb();
-	return ret;
-}
+({									\
+	unsigned ret = __read_seqcount_begin(s);			\
+									\
+	smp_rmb();							\
+	ret;								\
+})
 
 /**
  * read_seqcount_begin() - begin a seqcount_t read critical section
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * Return: count to be passed to read_seqcount_retry()
  */
 #define read_seqcount_begin(s)						\
-	read_seqcount_t_begin(__seqcount_ptr(s))
-
-static inline unsigned read_seqcount_t_begin(const seqcount_t *s)
-{
-	seqcount_lockdep_reader_access(s);
-	return raw_read_seqcount_t_begin(s);
-}
+({									\
+	seqcount_lockdep_reader_access(__seqcount_ptr(s));		\
+	raw_read_seqcount_begin(s);					\
+})
 
 /**
  * raw_read_seqcount() - read the raw seqcount_t counter value
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * raw_read_seqcount opens a read critical section of the given
  * seqcount_t, without any lockdep checking, and without checking or
@@ -324,20 +367,18 @@ static inline unsigned read_seqcount_t_begin(const seqcount_t *s)
  * Return: count to be passed to read_seqcount_retry()
  */
 #define raw_read_seqcount(s)						\
-	raw_read_seqcount_t(__seqcount_ptr(s))
-
-static inline unsigned raw_read_seqcount_t(const seqcount_t *s)
-{
-	unsigned ret = READ_ONCE(s->sequence);
-	smp_rmb();
-	kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX);
-	return ret;
-}
+({									\
+	unsigned ret = __seqcount_sequence(s);				\
+									\
+	smp_rmb();							\
+	kcsan_atomic_next(KCSAN_SEQLOCK_REGION_MAX);			\
+	ret;								\
+})
 
 /**
  * raw_seqcount_begin() - begin a seqcount_t read critical section w/o
  *                        lockdep and w/o counter stabilization
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * raw_seqcount_begin opens a read critical section of the given
  * seqcount_t. Unlike read_seqcount_begin(), this function will not wait
@@ -352,20 +393,17 @@ static inline unsigned raw_read_seqcount_t(const seqcount_t *s)
  * Return: count to be passed to read_seqcount_retry()
  */
 #define raw_seqcount_begin(s)						\
-	raw_seqcount_t_begin(__seqcount_ptr(s))
-
-static inline unsigned raw_seqcount_t_begin(const seqcount_t *s)
-{
-	/*
-	 * If the counter is odd, let read_seqcount_retry() fail
-	 * by decrementing the counter.
-	 */
-	return raw_read_seqcount_t(s) & ~1;
-}
+({									\
+	/*								\
+	 * If the counter is odd, let read_seqcount_retry() fail	\
+	 * by decrementing the counter.					\
+	 */								\
+	raw_read_seqcount(s) & ~1;					\
+})
 
 /**
  * __read_seqcount_retry() - end a seqcount_t read section w/o barrier
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  * @start: count, from read_seqcount_begin()
  *
  * __read_seqcount_retry is like read_seqcount_retry, but has no smp_rmb()
@@ -389,7 +427,7 @@ static inline int __read_seqcount_t_retry(const seqcount_t *s, unsigned start)
 
 /**
  * read_seqcount_retry() - end a seqcount_t read critical section
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  * @start: count, from read_seqcount_begin()
  *
  * read_seqcount_retry closes the read critical section of given
@@ -407,13 +445,22 @@ static inline int read_seqcount_t_retry(const seqcount_t *s, unsigned start)
 	return __read_seqcount_t_retry(s, start);
 }
 
+/*
+ * Automatically disable preemption for seqcount_LOCKTYPE_t writers, if the
+ * associated lock does not implicitly disable preemption.
+ *
+ * Don't do it for PREEMPT_RT. Check __SEQ_LOCK() for rationale.
+ */
+#define __seq_enforce_preemption_protection(s)				\
+	(!IS_ENABLED(CONFIG_PREEMPT_RT) && __seqcount_lock_preemptible(s))
+
 /**
  * raw_write_seqcount_begin() - start a seqcount_t write section w/o lockdep
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  */
 #define raw_write_seqcount_begin(s)					\
 do {									\
-	if (__seqcount_lock_preemptible(s))				\
+	if (__seq_enforce_preemption_protection(s))			\
 		preempt_disable();					\
 									\
 	raw_write_seqcount_t_begin(__seqcount_ptr(s));			\
@@ -428,13 +475,13 @@ static inline void raw_write_seqcount_t_begin(seqcount_t *s)
 
 /**
  * raw_write_seqcount_end() - end a seqcount_t write section w/o lockdep
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  */
 #define raw_write_seqcount_end(s)					\
 do {									\
 	raw_write_seqcount_t_end(__seqcount_ptr(s));			\
 									\
-	if (__seqcount_lock_preemptible(s))				\
+	if (__seq_enforce_preemption_protection(s))			\
 		preempt_enable();					\
 } while (0)
 
@@ -448,7 +495,7 @@ static inline void raw_write_seqcount_t_end(seqcount_t *s)
 /**
  * write_seqcount_begin_nested() - start a seqcount_t write section with
  *                                 custom lockdep nesting level
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  * @subclass: lockdep nesting level
  *
  * See Documentation/locking/lockdep-design.rst
@@ -457,7 +504,7 @@ static inline void raw_write_seqcount_t_end(seqcount_t *s)
 do {									\
 	__seqcount_assert_lock_held(s);					\
 									\
-	if (__seqcount_lock_preemptible(s))				\
+	if (__seq_enforce_preemption_protection(s))			\
 		preempt_disable();					\
 									\
 	write_seqcount_t_begin_nested(__seqcount_ptr(s), subclass);	\
@@ -471,7 +518,7 @@ static inline void write_seqcount_t_begin_nested(seqcount_t *s, int subclass)
 
 /**
  * write_seqcount_begin() - start a seqcount_t write side critical section
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * write_seqcount_begin opens a write side critical section of the given
  * seqcount_t.
@@ -484,7 +531,7 @@ static inline void write_seqcount_t_begin_nested(seqcount_t *s, int subclass)
 do {									\
 	__seqcount_assert_lock_held(s);					\
 									\
-	if (__seqcount_lock_preemptible(s))				\
+	if (__seq_enforce_preemption_protection(s))			\
 		preempt_disable();					\
 									\
 	write_seqcount_t_begin(__seqcount_ptr(s));			\
@@ -497,7 +544,7 @@ static inline void write_seqcount_t_begin(seqcount_t *s)
 
 /**
  * write_seqcount_end() - end a seqcount_t write side critical section
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * The write section must've been opened with write_seqcount_begin().
  */
@@ -505,7 +552,7 @@ static inline void write_seqcount_t_begin(seqcount_t *s)
 do {									\
 	write_seqcount_t_end(__seqcount_ptr(s));			\
 									\
-	if (__seqcount_lock_preemptible(s))				\
+	if (__seq_enforce_preemption_protection(s))			\
 		preempt_enable();					\
 } while (0)
 
@@ -517,7 +564,7 @@ static inline void write_seqcount_t_end(seqcount_t *s)
 
 /**
  * raw_write_seqcount_barrier() - do a seqcount_t write barrier
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * This can be used to provide an ordering guarantee instead of the usual
  * consistency guarantee. It is one wmb cheaper, because it can collapse
@@ -571,7 +618,7 @@ static inline void raw_write_seqcount_t_barrier(seqcount_t *s)
 /**
  * write_seqcount_invalidate() - invalidate in-progress seqcount_t read
  *                               side operations
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * After write_seqcount_invalidate, no seqcount_t read side operations
  * will complete successfully and see data older than this.
@@ -589,7 +636,7 @@ static inline void write_seqcount_t_invalidate(seqcount_t *s)
 
 /**
  * raw_read_seqcount_latch() - pick even/odd seqcount_t latch data copy
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * Use seqcount_t latching to switch between two storage places protected
  * by a sequence counter. Doing so allows having interruptible, preemptible,
@@ -614,7 +661,7 @@ static inline int raw_read_seqcount_t_latch(seqcount_t *s)
 
 /**
  * raw_write_seqcount_latch() - redirect readers to even/odd copy
- * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants
+ * @s: Pointer to seqcount_t or any of the seqcount_LOCKTYPE_t variants
  *
  * The latch technique is a multiversion concurrency control method that allows
  * queries during non-atomic modifications. If you can guarantee queries never
@@ -714,13 +761,17 @@ static inline void raw_write_seqcount_t_latch(seqcount_t *s)
  *    - Documentation/locking/seqlock.rst
  */
 typedef struct {
-	struct seqcount seqcount;
+	/*
+	 * Make sure that readers don't starve writers on PREEMPT_RT: use
+	 * seqcount_spinlock_t instead of seqcount_t. Check __SEQ_LOCK().
+	 */
+	seqcount_spinlock_t seqcount;
 	spinlock_t lock;
 } seqlock_t;
 
 #define __SEQLOCK_UNLOCKED(lockname)					\
 	{								\
-		.seqcount = SEQCNT_ZERO(lockname),			\
+		.seqcount = SEQCNT_SPINLOCK_ZERO(lockname, &(lockname).lock), \
 		.lock =	__SPIN_LOCK_UNLOCKED(lockname)			\
 	}
 
@@ -730,8 +781,8 @@ typedef struct {
  */
 #define seqlock_init(sl)						\
 	do {								\
-		seqcount_init(&(sl)->seqcount);				\
 		spin_lock_init(&(sl)->lock);				\
+		seqcount_spinlock_init(&(sl)->seqcount, &(sl)->lock);	\
 	} while (0)
 
 /**
@@ -778,6 +829,12 @@ static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start)
 	return read_seqcount_retry(&sl->seqcount, start);
 }
 
+/*
+ * For all seqlock_t write side functions, use write_seqcount_*t*_begin()
+ * instead of the generic write_seqcount_begin(). This way, no redundant
+ * lockdep_assert_held() checks are added.
+ */
+
 /**
  * write_seqlock() - start a seqlock_t write side critical section
  * @sl: Pointer to seqlock_t
@@ -794,7 +851,7 @@ static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start)
 static inline void write_seqlock(seqlock_t *sl)
 {
 	spin_lock(&sl->lock);
-	write_seqcount_t_begin(&sl->seqcount);
+	write_seqcount_t_begin(&sl->seqcount.seqcount);
 }
 
 /**
@@ -806,7 +863,7 @@ static inline void write_seqlock(seqlock_t *sl)
  */
 static inline void write_sequnlock(seqlock_t *sl)
 {
-	write_seqcount_t_end(&sl->seqcount);
+	write_seqcount_t_end(&sl->seqcount.seqcount);
 	spin_unlock(&sl->lock);
 }
 
@@ -820,7 +877,7 @@ static inline void write_sequnlock(seqlock_t *sl)
 static inline void write_seqlock_bh(seqlock_t *sl)
 {
 	spin_lock_bh(&sl->lock);
-	write_seqcount_t_begin(&sl->seqcount);
+	write_seqcount_t_begin(&sl->seqcount.seqcount);
 }
 
 /**
@@ -833,7 +890,7 @@ static inline void write_seqlock_bh(seqlock_t *sl)
  */
 static inline void write_sequnlock_bh(seqlock_t *sl)
 {
-	write_seqcount_t_end(&sl->seqcount);
+	write_seqcount_t_end(&sl->seqcount.seqcount);
 	spin_unlock_bh(&sl->lock);
 }
 
@@ -847,7 +904,7 @@ static inline void write_sequnlock_bh(seqlock_t *sl)
 static inline void write_seqlock_irq(seqlock_t *sl)
 {
 	spin_lock_irq(&sl->lock);
-	write_seqcount_t_begin(&sl->seqcount);
+	write_seqcount_t_begin(&sl->seqcount.seqcount);
 }
 
 /**
@@ -859,7 +916,7 @@ static inline void write_seqlock_irq(seqlock_t *sl)
  */
 static inline void write_sequnlock_irq(seqlock_t *sl)
 {
-	write_seqcount_t_end(&sl->seqcount);
+	write_seqcount_t_end(&sl->seqcount.seqcount);
 	spin_unlock_irq(&sl->lock);
 }
 
@@ -868,7 +925,7 @@ static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl)
 	unsigned long flags;
 
 	spin_lock_irqsave(&sl->lock, flags);
-	write_seqcount_t_begin(&sl->seqcount);
+	write_seqcount_t_begin(&sl->seqcount.seqcount);
 	return flags;
 }
 
@@ -897,7 +954,7 @@ static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl)
 static inline void
 write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags)
 {
-	write_seqcount_t_end(&sl->seqcount);
+	write_seqcount_t_end(&sl->seqcount.seqcount);
 	spin_unlock_irqrestore(&sl->lock, flags);
 }
 
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 2b70f736b091d..68d756373b53b 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -7,6 +7,7 @@
 #ifndef _LINUX_SERIAL_8250_H
 #define _LINUX_SERIAL_8250_H
 
+#include <linux/atomic.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
 #include <linux/platform_device.h>
@@ -125,6 +126,8 @@ struct uart_8250_port {
 #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
 	unsigned char		msr_saved_flags;
 
+	atomic_t		console_printing;
+
 	struct uart_8250_dma	*dma;
 	const struct uart_8250_ops *ops;
 
@@ -180,6 +183,8 @@ void serial8250_init_port(struct uart_8250_port *up);
 void serial8250_set_defaults(struct uart_8250_port *up);
 void serial8250_console_write(struct uart_8250_port *up, const char *s,
 			      unsigned int count);
+void serial8250_console_write_atomic(struct uart_8250_port *up, const char *s,
+				     unsigned int count);
 int serial8250_console_setup(struct uart_port *port, char *options, bool probe);
 int serial8250_console_exit(struct uart_port *port);
 
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index a5a5d1d4d7b1d..0470d1582b09a 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -31,7 +31,7 @@ struct shmem_sb_info {
 	struct percpu_counter used_blocks;  /* How many are allocated */
 	unsigned long max_inodes;   /* How many inodes are allowed */
 	unsigned long free_inodes;  /* How many are left for allocation */
-	spinlock_t stat_lock;	    /* Serialize shmem_sb_info changes */
+	raw_spinlock_t stat_lock;   /* Serialize shmem_sb_info changes */
 	umode_t mode;		    /* Mount mode for root directory */
 	unsigned char huge;	    /* Whether to try for hugepages */
 	kuid_t uid;		    /* Mount uid for root directory */
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 7bbc0e9cf0847..3030d984a1442 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -263,6 +263,7 @@ static inline void init_sigpending(struct sigpending *sig)
 }
 
 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)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ab57cf787c1f5..b405990d5b5c2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -295,6 +295,7 @@ struct sk_buff_head {
 
 	__u32		qlen;
 	spinlock_t	lock;
+	raw_spinlock_t	raw_lock;
 };
 
 struct sk_buff;
@@ -1875,6 +1876,12 @@ static inline void skb_queue_head_init(struct sk_buff_head *list)
 	__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)
 {
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 80d557ef8a11c..47d666fa4fbae 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -236,6 +236,9 @@ static inline int get_boot_cpu_id(void)
 #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:
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index f2f12d746dbdb..38ff58065dfb1 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -309,7 +309,11 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 })
 
 /* Include rwlock functions */
-#include <linux/rwlock.h>
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/rwlock_rt.h>
+#else
+# include <linux/rwlock.h>
+#endif
 
 /*
  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@@ -320,6 +324,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 # include <linux/spinlock_api_up.h>
 #endif
 
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/spinlock_rt.h>
+#else /* PREEMPT_RT */
+
 /*
  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  */
@@ -454,6 +462,8 @@ static __always_inline int spin_is_contended(spinlock_t *lock)
 
 #define assert_spin_locked(lock)	assert_raw_spin_locked(&(lock)->rlock)
 
+#endif /* !PREEMPT_RT */
+
 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)
diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h
index 19a9be9d97ee5..da38149f28431 100644
--- a/include/linux/spinlock_api_smp.h
+++ b/include/linux/spinlock_api_smp.h
@@ -187,6 +187,8 @@ static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock)
 	return 0;
 }
 
-#include <linux/rwlock_api_smp.h>
+#ifndef CONFIG_PREEMPT_RT
+# include <linux/rwlock_api_smp.h>
+#endif
 
 #endif /* __LINUX_SPINLOCK_API_SMP_H */
diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
new file mode 100644
index 0000000000000..50f6456c9fd24
--- /dev/null
+++ b/include/linux/spinlock_rt.h
@@ -0,0 +1,154 @@
+#ifndef __LINUX_SPINLOCK_RT_H
+#define __LINUX_SPINLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+#include <linux/bug.h>
+
+extern void
+__rt_spin_lock_init(spinlock_t *lock, const 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_lock_unlock(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.
+ * Migrate disable handling must be done at the call site.
+ */
+extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_trylock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
+
+#define spin_lock(lock)			rt_spin_lock(lock)
+
+#define spin_lock_bh(lock)			\
+	do {					\
+		local_bh_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;				\
+	__locked = spin_do_trylock(lock);	\
+	__locked;				\
+})
+
+#ifdef CONFIG_LOCKDEP
+# define spin_lock_nested(lock, subclass)		\
+	do {						\
+		rt_spin_lock_nested(lock, subclass);	\
+	} while (0)
+
+#define spin_lock_bh_nested(lock, subclass)		\
+	do {						\
+		local_bh_disable();			\
+		rt_spin_lock_nested(lock, subclass);	\
+	} while (0)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		rt_spin_lock_nested(lock, subclass);	 \
+	} while (0)
+#else
+# define spin_lock_nested(lock, subclass)	spin_lock(lock)
+# define spin_lock_bh_nested(lock, subclass)	spin_lock_bh(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)			rt_spin_unlock(lock)
+
+#define spin_unlock_bh(lock)				\
+	do {						\
+		rt_spin_unlock(lock);			\
+		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))
+
+#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));
+}
+
+#endif
diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h
index b981caafe8bf1..8d896d3e1a017 100644
--- a/include/linux/spinlock_types.h
+++ b/include/linux/spinlock_types.h
@@ -9,93 +9,15 @@
  * Released under the General Public License (GPL).
  */
 
-#if defined(CONFIG_SMP)
-# include <asm/spinlock_types.h>
+#include <linux/spinlock_types_raw.h>
+
+#ifndef CONFIG_PREEMPT_RT
+# include <linux/spinlock_types_nort.h>
+# include <linux/rwlock_types.h>
 #else
-# include <linux/spinlock_types_up.h>
+# include <linux/rtmutex.h>
+# include <linux/spinlock_types_rt.h>
+# include <linux/rwlock_types_rt.h>
 #endif
 
-#include <linux/lockdep_types.h>
-
-typedef struct raw_spinlock {
-	arch_spinlock_t raw_lock;
-#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 RAW_SPIN_DEP_MAP_INIT(lockname)		\
-	.dep_map = {					\
-		.name = #lockname,			\
-		.wait_type_inner = LD_WAIT_SPIN,	\
-	}
-# define SPIN_DEP_MAP_INIT(lockname)			\
-	.dep_map = {					\
-		.name = #lockname,			\
-		.wait_type_inner = LD_WAIT_CONFIG,	\
-	}
-#else
-# define RAW_SPIN_DEP_MAP_INIT(lockname)
-# 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)		\
-	RAW_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)	\
-	{					\
-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
-	SPIN_DEBUG_INIT(lockname)		\
-	SPIN_DEP_MAP_INIT(lockname) }
-
-#define __SPIN_LOCK_INITIALIZER(lockname) \
-	{ { .rlock = ___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 */
diff --git a/include/linux/spinlock_types_nort.h b/include/linux/spinlock_types_nort.h
new file mode 100644
index 0000000000000..e4549f0dd197b
--- /dev/null
+++ b/include/linux/spinlock_types_nort.h
@@ -0,0 +1,39 @@
+#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)	\
+{						\
+	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+	SPIN_DEBUG_INIT(lockname)		\
+	SPIN_DEP_MAP_INIT(lockname) }
+
+#define __SPIN_LOCK_INITIALIZER(lockname) \
+	{ { .rlock = ___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
diff --git a/include/linux/spinlock_types_raw.h b/include/linux/spinlock_types_raw.h
new file mode 100644
index 0000000000000..1d4a180e983d7
--- /dev/null
+++ b/include/linux/spinlock_types_raw.h
@@ -0,0 +1,65 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
+#define __LINUX_SPINLOCK_TYPES_RAW_H
+
+#include <linux/types.h>
+
+#if defined(CONFIG_SMP)
+# include <asm/spinlock_types.h>
+#else
+# include <linux/spinlock_types_up.h>
+#endif
+
+#include <linux/lockdep_types.h>
+
+typedef struct raw_spinlock {
+	arch_spinlock_t raw_lock;
+#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 RAW_SPIN_DEP_MAP_INIT(lockname)		\
+	.dep_map = {					\
+		.name = #lockname,			\
+		.wait_type_inner = LD_WAIT_SPIN,	\
+	}
+# define SPIN_DEP_MAP_INIT(lockname)			\
+	.dep_map = {					\
+		.name = #lockname,			\
+		.wait_type_inner = LD_WAIT_CONFIG,	\
+	}
+#else
+# define RAW_SPIN_DEP_MAP_INIT(lockname)
+# 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)		\
+	RAW_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
diff --git a/include/linux/spinlock_types_rt.h b/include/linux/spinlock_types_rt.h
new file mode 100644
index 0000000000000..3e3d8c5f7a9ad
--- /dev/null
+++ b/include/linux/spinlock_types_rt.h
@@ -0,0 +1,48 @@
+#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
+
+#include <linux/cache.h>
+
+/*
+ * 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)
+
+#endif
diff --git a/include/linux/spinlock_types_up.h b/include/linux/spinlock_types_up.h
index c09b6407ae1b3..b0243ba07fb78 100644
--- a/include/linux/spinlock_types_up.h
+++ b/include/linux/spinlock_types_up.h
@@ -1,10 +1,6 @@
 #ifndef __LINUX_SPINLOCK_TYPES_UP_H
 #define __LINUX_SPINLOCK_TYPES_UP_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 /*
  * include/linux/spinlock_types_up.h - spinlock type definitions for UP
  *
diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h
index 76d8b09384a7a..99996aefc7a3e 100644
--- a/include/linux/stop_machine.h
+++ b/include/linux/stop_machine.h
@@ -26,6 +26,8 @@ struct cpu_stop_work {
 	cpu_stop_fn_t		fn;
 	void			*arg;
 	struct cpu_stop_done	*done;
+	/* Did not run due to disabled stopper; for nowait debug checks */
+	bool			disabled;
 };
 
 int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index e93e249a4e9bf..c88b9cecc78aa 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -97,7 +97,17 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
 #define test_thread_flag(flag) \
 	test_ti_thread_flag(current_thread_info(), flag)
 
-#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
+#ifdef CONFIG_PREEMPT_LAZY
+#define tif_need_resched()	(test_thread_flag(TIF_NEED_RESCHED) || \
+				 test_thread_flag(TIF_NEED_RESCHED_LAZY))
+#define tif_need_resched_now()	(test_thread_flag(TIF_NEED_RESCHED))
+#define tif_need_resched_lazy()	test_thread_flag(TIF_NEED_RESCHED_LAZY))
+
+#else
+#define tif_need_resched()	test_thread_flag(TIF_NEED_RESCHED)
+#define tif_need_resched_now()	test_thread_flag(TIF_NEED_RESCHED)
+#define tif_need_resched_lazy()	0
+#endif
 
 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
 static inline int arch_within_stack_frames(const void * const stack,
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 5c69433540494..75e3acd596358 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -67,6 +67,8 @@ struct trace_entry {
 	unsigned char		flags;
 	unsigned char		preempt_count;
 	int			pid;
+	unsigned char		migrate_disable;
+	unsigned char		preempt_lazy_count;
 };
 
 #define TRACE_EVENT_TYPE_MAX						\
diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
index c6abb79501b33..72bf38b97df88 100644
--- a/include/linux/u64_stats_sync.h
+++ b/include/linux/u64_stats_sync.h
@@ -66,7 +66,7 @@
 #include <linux/seqlock.h>
 
 struct u64_stats_sync {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG==32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	seqcount_t	seq;
 #endif
 };
@@ -117,22 +117,26 @@ static inline void u64_stats_inc(u64_stats_t *p)
 
 static inline void u64_stats_init(struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	seqcount_init(&syncp->seq);
 #endif
 }
 
 static inline void u64_stats_update_begin(struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_disable();
 	write_seqcount_begin(&syncp->seq);
 #endif
 }
 
 static inline void u64_stats_update_end(struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	write_seqcount_end(&syncp->seq);
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_enable();
 #endif
 }
 
@@ -141,8 +145,11 @@ u64_stats_update_begin_irqsave(struct u64_stats_sync *syncp)
 {
 	unsigned long flags = 0;
 
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
-	local_irq_save(flags);
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_disable();
+	else
+		local_irq_save(flags);
 	write_seqcount_begin(&syncp->seq);
 #endif
 	return flags;
@@ -152,15 +159,18 @@ static inline void
 u64_stats_update_end_irqrestore(struct u64_stats_sync *syncp,
 				unsigned long flags)
 {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	write_seqcount_end(&syncp->seq);
-	local_irq_restore(flags);
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		preempt_enable();
+	else
+		local_irq_restore(flags);
 #endif
 }
 
 static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	return read_seqcount_begin(&syncp->seq);
 #else
 	return 0;
@@ -169,7 +179,7 @@ static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *
 
 static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT))
 	preempt_disable();
 #endif
 	return __u64_stats_fetch_begin(syncp);
@@ -178,7 +188,7 @@ static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *sy
 static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
 					 unsigned int start)
 {
-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
 	return read_seqcount_retry(&syncp->seq, start);
 #else
 	return false;
@@ -188,7 +198,7 @@ static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
 static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
 					 unsigned int start)
 {
-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT))
 	preempt_enable();
 #endif
 	return __u64_stats_fetch_retry(syncp, start);
@@ -202,7 +212,9 @@ static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
  */
 static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync *syncp)
 {
-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT)
+	preempt_disable();
+#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP)
 	local_irq_disable();
 #endif
 	return __u64_stats_fetch_begin(syncp);
@@ -211,7 +223,9 @@ static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync
 static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync *syncp,
 					     unsigned int start)
 {
-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
+#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT)
+	preempt_enable();
+#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP)
 	local_irq_enable();
 #endif
 	return __u64_stats_fetch_retry(syncp, start);
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 91220ace31da9..d6bb3ce547c0a 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -63,7 +63,9 @@ DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
  */
 static inline void __count_vm_event(enum vm_event_item item)
 {
+	preempt_disable_rt();
 	raw_cpu_inc(vm_event_states.event[item]);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_event(enum vm_event_item item)
@@ -73,7 +75,9 @@ static inline void count_vm_event(enum vm_event_item item)
 
 static inline void __count_vm_events(enum vm_event_item item, long delta)
 {
+	preempt_disable_rt();
 	raw_cpu_add(vm_event_states.event[item], delta);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_events(enum vm_event_item item, long delta)
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 898c890fc153f..f3a30c1d587dd 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -10,6 +10,7 @@
 
 #include <asm/current.h>
 #include <uapi/linux/wait.h>
+#include <linux/atomic.h>
 
 typedef struct wait_queue_entry wait_queue_entry_t;
 
diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
index 850424e5d0306..8ef2feb0d8fef 100644
--- a/include/linux/ww_mutex.h
+++ b/include/linux/ww_mutex.h
@@ -28,6 +28,14 @@ struct ww_class {
 	unsigned int is_wait_die;
 };
 
+struct ww_mutex {
+	struct mutex base;
+	struct ww_acquire_ctx *ctx;
+#ifdef CONFIG_DEBUG_MUTEXES
+	struct ww_class *ww_class;
+#endif
+};
+
 struct ww_acquire_ctx {
 	struct task_struct *task;
 	unsigned long stamp;
diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 1424e02cef90c..163f8415e5db5 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -6,6 +6,7 @@
 #include <linux/socket.h>
 #include <linux/rtnetlink.h>
 #include <linux/pkt_sched.h>
+#include <net/net_seq_lock.h>
 
 /* Note: this used to be in include/uapi/linux/gen_stats.h */
 struct gnet_stats_basic_packed {
@@ -42,15 +43,15 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
 				 spinlock_t *lock, struct gnet_dump *d,
 				 int padattr);
 
-int gnet_stats_copy_basic(const seqcount_t *running,
+int gnet_stats_copy_basic(net_seqlock_t *running,
 			  struct gnet_dump *d,
 			  struct gnet_stats_basic_cpu __percpu *cpu,
 			  struct gnet_stats_basic_packed *b);
-void __gnet_stats_copy_basic(const seqcount_t *running,
+void __gnet_stats_copy_basic(net_seqlock_t *running,
 			     struct gnet_stats_basic_packed *bstats,
 			     struct gnet_stats_basic_cpu __percpu *cpu,
 			     struct gnet_stats_basic_packed *b);
-int gnet_stats_copy_basic_hw(const seqcount_t *running,
+int gnet_stats_copy_basic_hw(net_seqlock_t *running,
 			     struct gnet_dump *d,
 			     struct gnet_stats_basic_cpu __percpu *cpu,
 			     struct gnet_stats_basic_packed *b);
@@ -70,13 +71,13 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
 		      spinlock_t *lock,
-		      seqcount_t *running, struct nlattr *opt);
+		      net_seqlock_t *running, struct nlattr *opt);
 void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **ptr,
 			  spinlock_t *lock,
-			  seqcount_t *running, struct nlattr *opt);
+			  net_seqlock_t *running, struct nlattr *opt);
 bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
 bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
 			struct gnet_stats_rate_est64 *sample);
diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h
new file mode 100644
index 0000000000000..95a497a72e511
--- /dev/null
+++ b/include/net/net_seq_lock.h
@@ -0,0 +1,24 @@
+#ifndef __NET_NET_SEQ_LOCK_H__
+#define __NET_NET_SEQ_LOCK_H__
+
+#ifdef CONFIG_PREEMPT_RT
+# define net_seqlock_t			seqlock_t
+# define net_seq_begin(__r)		read_seqbegin(__r)
+# define net_seq_retry(__r, __s)	read_seqretry(__r, __s)
+
+static inline int try_write_seqlock(seqlock_t *sl)
+{
+	if (spin_trylock(&sl->lock)) {
+		write_seqcount_begin(&sl->seqcount);
+		return 1;
+	}
+	return 0;
+}
+
+#else
+# define net_seqlock_t			seqcount_t
+# define net_seq_begin(__r)		read_seqcount_begin(__r)
+# define net_seq_retry(__r, __s)	read_seqcount_retry(__r, __s)
+#endif
+
+#endif
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index d60e7c39d60c7..796ac453d9519 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -10,6 +10,7 @@
 #include <linux/percpu.h>
 #include <linux/dynamic_queue_limits.h>
 #include <linux/list.h>
+#include <net/net_seq_lock.h>
 #include <linux/refcount.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
@@ -100,7 +101,7 @@ struct Qdisc {
 	struct sk_buff_head	gso_skb ____cacheline_aligned_in_smp;
 	struct qdisc_skb_head	q;
 	struct gnet_stats_basic_packed bstats;
-	seqcount_t		running;
+	net_seqlock_t		running;
 	struct gnet_stats_queue	qstats;
 	unsigned long		state;
 	struct Qdisc            *next_sched;
@@ -138,7 +139,11 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc)
 {
 	if (qdisc->flags & TCQ_F_NOLOCK)
 		return spin_is_locked(&qdisc->seqlock);
+#ifdef CONFIG_PREEMPT_RT
+	return spin_is_locked(&qdisc->running.lock) ? true : false;
+#else
 	return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
+#endif
 }
 
 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
@@ -162,17 +167,27 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
 	} else if (qdisc_is_running(qdisc)) {
 		return false;
 	}
+#ifdef CONFIG_PREEMPT_RT
+	if (try_write_seqlock(&qdisc->running))
+		return true;
+	return false;
+#else
 	/* Variant of write_seqcount_begin() telling lockdep a trylock
 	 * was attempted.
 	 */
 	raw_write_seqcount_begin(&qdisc->running);
 	seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
 	return true;
+#endif
 }
 
 static inline void qdisc_run_end(struct Qdisc *qdisc)
 {
+#ifdef CONFIG_PREEMPT_RT
+	write_sequnlock(&qdisc->running);
+#else
 	write_seqcount_end(&qdisc->running);
+#endif
 	if (qdisc->flags & TCQ_F_NOLOCK)
 		spin_unlock(&qdisc->seqlock);
 }
@@ -547,7 +562,7 @@ static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
 	return qdisc_lock(root);
 }
 
-static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
+static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
 {
 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
 
diff --git a/init/Kconfig b/init/Kconfig
index d6a0b31b13dc9..7743d6e62a06a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -964,6 +964,7 @@ config CFS_BANDWIDTH
 config RT_GROUP_SCHED
 	bool "Group scheduling for SCHED_RR/FIFO"
 	depends on CGROUP_SCHED
+	depends on !PREEMPT_RT
 	default n
 	help
 	  This feature lets you explicitly allocate real CPU bandwidth
@@ -1871,6 +1872,7 @@ choice
 
 config SLAB
 	bool "SLAB"
+	depends on !PREEMPT_RT
 	select HAVE_HARDENED_USERCOPY_ALLOCATOR
 	help
 	  The regular slab allocator that is established and known to work
@@ -1891,6 +1893,7 @@ config SLUB
 config SLOB
 	depends on EXPERT
 	bool "SLOB (Simple Allocator)"
+	depends on !PREEMPT_RT
 	help
 	   SLOB replaces the stock allocator with a drastically simpler
 	   allocator. SLOB is generally more space efficient but
@@ -1957,7 +1960,7 @@ config SHUFFLE_PAGE_ALLOCATOR
 
 config SLUB_CPU_PARTIAL
 	default y
-	depends on SLUB && SMP
+	depends on SLUB && SMP && !PREEMPT_RT
 	bool "SLUB per cpu partial cache"
 	help
 	  Per cpu partial caches accelerate objects allocation and freeing
diff --git a/init/init_task.c b/init/init_task.c
index f6889fce64af7..c32b16be75332 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -82,6 +82,10 @@ struct task_struct init_task
 	.cpus_ptr	= &init_task.cpus_mask,
 	.cpus_mask	= CPU_MASK_ALL,
 	.nr_cpus_allowed= NR_CPUS,
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT) && \
+    defined(CONFIG_SCHED_DEBUG)
+	.pinned_on_cpu	= -1,
+#endif
 	.mm		= NULL,
 	.active_mm	= &init_mm,
 	.restart_block	= {
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
index bf82259cff965..c1203c14fee92 100644
--- a/kernel/Kconfig.preempt
+++ b/kernel/Kconfig.preempt
@@ -1,5 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+config HAVE_PREEMPT_LAZY
+	bool
+
+config PREEMPT_LAZY
+	def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT
+
 choice
 	prompt "Preemption Model"
 	default PREEMPT_NONE
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 642415b8c3c9e..daca5e74d75ed 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -345,7 +345,7 @@ void cpuset_read_unlock(void)
 	percpu_up_read(&cpuset_rwsem);
 }
 
-static DEFINE_SPINLOCK(callback_lock);
+static DEFINE_RAW_SPINLOCK(callback_lock);
 
 static struct workqueue_struct *cpuset_migrate_mm_wq;
 
@@ -1257,7 +1257,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
 	 * Newly added CPUs will be removed from effective_cpus and
 	 * newly deleted ones will be added back to effective_cpus.
 	 */
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	if (adding) {
 		cpumask_or(parent->subparts_cpus,
 			   parent->subparts_cpus, tmp->addmask);
@@ -1276,7 +1276,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
 	}
 
 	parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	return cmd == partcmd_update;
 }
@@ -1381,7 +1381,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
 			continue;
 		rcu_read_unlock();
 
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 
 		cpumask_copy(cp->effective_cpus, tmp->new_cpus);
 		if (cp->nr_subparts_cpus &&
@@ -1412,7 +1412,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
 					= cpumask_weight(cp->subparts_cpus);
 			}
 		}
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 
 		WARN_ON(!is_in_v2_mode() &&
 			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
@@ -1530,7 +1530,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 			return -EINVAL;
 	}
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
 
 	/*
@@ -1541,7 +1541,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 			       cs->cpus_allowed);
 		cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
 	}
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	update_cpumasks_hier(cs, &tmp);
 
@@ -1735,9 +1735,9 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
 			continue;
 		rcu_read_unlock();
 
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		cp->effective_mems = *new_mems;
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 
 		WARN_ON(!is_in_v2_mode() &&
 			!nodes_equal(cp->mems_allowed, cp->effective_mems));
@@ -1805,9 +1805,9 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
 	if (retval < 0)
 		goto done;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->mems_allowed = trialcs->mems_allowed;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	/* use trialcs->mems_allowed as a temp variable */
 	update_nodemasks_hier(cs, &trialcs->mems_allowed);
@@ -1898,9 +1898,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 	spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
 			|| (is_spread_page(cs) != is_spread_page(trialcs)));
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->flags = trialcs->flags;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
 		rebuild_sched_domains_locked();
@@ -2409,7 +2409,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
 	cpuset_filetype_t type = seq_cft(sf)->private;
 	int ret = 0;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 
 	switch (type) {
 	case FILE_CPULIST:
@@ -2431,7 +2431,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
 		ret = -EINVAL;
 	}
 
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 	return ret;
 }
 
@@ -2744,14 +2744,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 
 	cpuset_inc();
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	if (is_in_v2_mode()) {
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 		cs->effective_mems = parent->effective_mems;
 		cs->use_parent_ecpus = true;
 		parent->child_ecpus_count++;
 	}
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
 		goto out_unlock;
@@ -2778,12 +2778,12 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 	}
 	rcu_read_unlock();
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->mems_allowed = parent->mems_allowed;
 	cs->effective_mems = parent->mems_allowed;
 	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
 	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
 	put_online_cpus();
@@ -2839,7 +2839,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css)
 static void cpuset_bind(struct cgroup_subsys_state *root_css)
 {
 	percpu_down_write(&cpuset_rwsem);
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 
 	if (is_in_v2_mode()) {
 		cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
@@ -2850,7 +2850,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
 		top_cpuset.mems_allowed = top_cpuset.effective_mems;
 	}
 
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 	percpu_up_write(&cpuset_rwsem);
 }
 
@@ -2947,12 +2947,12 @@ hotplug_update_tasks_legacy(struct cpuset *cs,
 {
 	bool is_empty;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->cpus_allowed, new_cpus);
 	cpumask_copy(cs->effective_cpus, new_cpus);
 	cs->mems_allowed = *new_mems;
 	cs->effective_mems = *new_mems;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	/*
 	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
@@ -2989,10 +2989,10 @@ hotplug_update_tasks(struct cpuset *cs,
 	if (nodes_empty(*new_mems))
 		*new_mems = parent_cs(cs)->effective_mems;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->effective_cpus, new_cpus);
 	cs->effective_mems = *new_mems;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (cpus_updated)
 		update_tasks_cpumask(cs);
@@ -3147,7 +3147,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
 
 	/* synchronize cpus_allowed to cpu_active_mask */
 	if (cpus_updated) {
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		if (!on_dfl)
 			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
 		/*
@@ -3167,17 +3167,17 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
 			}
 		}
 		cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 		/* we don't mess with cpumasks of tasks in top_cpuset */
 	}
 
 	/* synchronize mems_allowed to N_MEMORY */
 	if (mems_updated) {
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		if (!on_dfl)
 			top_cpuset.mems_allowed = new_mems;
 		top_cpuset.effective_mems = new_mems;
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 		update_tasks_nodemask(&top_cpuset);
 	}
 
@@ -3278,11 +3278,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 	rcu_read_lock();
 	guarantee_online_cpus(task_cs(tsk), pmask);
 	rcu_read_unlock();
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 }
 
 /**
@@ -3343,11 +3343,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
 	nodemask_t mask;
 	unsigned long flags;
 
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 	rcu_read_lock();
 	guarantee_online_mems(task_cs(tsk), &mask);
 	rcu_read_unlock();
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 
 	return mask;
 }
@@ -3439,14 +3439,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
 		return true;
 
 	/* Not hardwall and node outside mems_allowed: scan up cpusets */
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 
 	rcu_read_lock();
 	cs = nearest_hardwall_ancestor(task_cs(current));
 	allowed = node_isset(node, cs->mems_allowed);
 	rcu_read_unlock();
 
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 	return allowed;
 }
 
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index d51175cedfca4..b424f3157b345 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -149,8 +149,9 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
 		raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,
 						       cpu);
 		struct cgroup *pos = NULL;
+		unsigned long flags;
 
-		raw_spin_lock(cpu_lock);
+		raw_spin_lock_irqsave(cpu_lock, flags);
 		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
 			struct cgroup_subsys_state *css;
 
@@ -162,7 +163,7 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
 				css->ss->css_rstat_flush(css, cpu);
 			rcu_read_unlock();
 		}
-		raw_spin_unlock(cpu_lock);
+		raw_spin_unlock_irqrestore(cpu_lock, flags);
 
 		/* if @may_sleep, play nice and yield if necessary */
 		if (may_sleep && (need_resched() ||
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ff2578ecf17d..541f537871483 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -864,6 +864,15 @@ static int take_cpu_down(void *_param)
 	int err, cpu = smp_processor_id();
 	int ret;
 
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * If any tasks disabled migration before we got here,
+	 * go back and sleep again.
+	 */
+	if (cpu_nr_pinned(cpu))
+		return -EAGAIN;
+#endif
+
 	/* Ensure this CPU doesn't handle any more interrupts. */
 	err = __cpu_disable();
 	if (err < 0)
@@ -893,6 +902,10 @@ static int take_cpu_down(void *_param)
 	return 0;
 }
 
+#ifdef CONFIG_PREEMPT_RT
+struct task_struct *takedown_cpu_task;
+#endif
+
 static int takedown_cpu(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
@@ -907,11 +920,39 @@ static int takedown_cpu(unsigned int cpu)
 	 */
 	irq_lock_sparse();
 
+#ifdef CONFIG_PREEMPT_RT
+	WARN_ON_ONCE(takedown_cpu_task);
+	takedown_cpu_task = current;
+
+again:
+	/*
+	 * If a task pins this CPU after we pass this check, take_cpu_down
+	 * will return -EAGAIN.
+	 */
+	for (;;) {
+		int nr_pinned;
+
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		nr_pinned = cpu_nr_pinned(cpu);
+		if (nr_pinned == 0)
+			break;
+		schedule();
+	}
+	set_current_state(TASK_RUNNING);
+#endif
+
 	/*
 	 * So now all preempt/rcu users must observe !cpu_active().
 	 */
 	err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
+#ifdef CONFIG_PREEMPT_RT
+	if (err == -EAGAIN)
+		goto again;
+#endif
 	if (err) {
+#ifdef CONFIG_PREEMPT_RT
+		takedown_cpu_task = NULL;
+#endif
 		/* CPU refused to die */
 		irq_unlock_sparse();
 		/* Unpark the hotplug thread so we can rollback there */
@@ -930,6 +971,9 @@ static int takedown_cpu(unsigned int cpu)
 	wait_for_ap_thread(st, false);
 	BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
 
+#ifdef CONFIG_PREEMPT_RT
+	takedown_cpu_task = NULL;
+#endif
 	/* Interrupts are moved away from the dying cpu, reenable alloc/free */
 	irq_unlock_sparse();
 
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index fcae019158cad..2f4806a6feef0 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -123,9 +123,17 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
 
 		local_irq_enable_exit_to_user(ti_work);
 
-		if (ti_work & _TIF_NEED_RESCHED)
+		if (ti_work & _TIF_NEED_RESCHED_MASK)
 			schedule();
 
+#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+		if (unlikely(current->forced_info.si_signo)) {
+			struct task_struct *t = current;
+			force_sig_info(&t->forced_info);
+			t->forced_info.si_signo = 0;
+		}
+#endif
+
 		if (ti_work & _TIF_UPROBE)
 			uprobe_notify_resume(regs);
 
@@ -329,7 +337,7 @@ void irqentry_exit_cond_resched(void)
 		rcu_irq_exit_check_preempt();
 		if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
 			WARN_ON_ONCE(!on_thread_stack());
-		if (need_resched())
+		if (should_resched(0))
 			preempt_schedule_irq();
 	}
 }
diff --git a/kernel/exit.c b/kernel/exit.c
index 733e80f334e71..a1756dcc17f2b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -151,7 +151,7 @@ static void __exit_signal(struct task_struct *tsk)
 	 * 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);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 4d32190861bdc..86dc0b03ed5c6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -42,6 +42,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/kprobes.h>
 #include <linux/vmacache.h>
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
@@ -287,7 +288,7 @@ static inline void free_thread_stack(struct task_struct *tsk)
 			return;
 		}
 
-		vfree_atomic(tsk->stack);
+		vfree(tsk->stack);
 		return;
 	}
 #endif
@@ -687,6 +688,19 @@ void __mmdrop(struct mm_struct *mm)
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * 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
+
 static void mmdrop_async_fn(struct work_struct *work)
 {
 	struct mm_struct *mm;
@@ -728,6 +742,15 @@ void __put_task_struct(struct task_struct *tsk)
 	WARN_ON(refcount_read(&tsk->usage));
 	WARN_ON(tsk == current);
 
+	/*
+	 * Remove function-return probe instances associated with this
+	 * task and put them back on the free list.
+	 */
+	kprobe_flush_task(tsk);
+
+	/* Task is done with its stack. */
+	put_task_stack(tsk);
+
 	cgroup_free(tsk);
 	task_numa_free(tsk, true);
 	security_task_free(tsk);
@@ -924,6 +947,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 	tsk->splice_pipe = NULL;
 	tsk->task_frag.page = NULL;
 	tsk->wake_q.next = NULL;
+	tsk->wake_q_sleeper.next = NULL;
 
 	account_kernel_stack(tsk, 1);
 
@@ -1969,6 +1993,7 @@ static __latent_entropy 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;
 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
diff --git a/kernel/futex.c b/kernel/futex.c
index a5876694a60eb..9853757335aed 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -869,7 +869,9 @@ static void exit_pi_state_list(struct task_struct *curr)
 		if (head->next != next) {
 			/* retain curr->pi_lock for the loop invariant */
 			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
+			raw_spin_unlock_irq(&curr->pi_lock);
 			spin_unlock(&hb->lock);
+			raw_spin_lock_irq(&curr->pi_lock);
 			put_pi_state(pi_state);
 			continue;
 		}
@@ -1479,6 +1481,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
 	struct task_struct *new_owner;
 	bool postunlock = false;
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 	int ret = 0;
 
 	new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
@@ -1538,13 +1541,13 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
 	pi_state->owner = new_owner;
 	raw_spin_unlock(&new_owner->pi_lock);
 
-	postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
-
+	postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q,
+					     &wake_sleeper_q);
 out_unlock:
 	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 
 	if (postunlock)
-		rt_mutex_postunlock(&wake_q);
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
 
 	return ret;
 }
@@ -2145,6 +2148,16 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
 				 */
 				requeue_pi_wake_futex(this, &key2, hb2);
 				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;
+				put_pi_state(pi_state);
+				continue;
 			} else if (ret) {
 				/*
 				 * rt_mutex_start_proxy_lock() detected a
@@ -2830,7 +2843,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
 		goto no_block;
 	}
 
-	rt_mutex_init_waiter(&rt_waiter);
+	rt_mutex_init_waiter(&rt_waiter, false);
 
 	/*
 	 * On PREEMPT_RT_FULL, when hb->lock becomes an rt_mutex, we must not
@@ -2846,6 +2859,14 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
 	 * before __rt_mutex_start_proxy_lock() is done.
 	 */
 	raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
+	/*
+	 * the migrate_disable() here disables migration in the in_atomic() fast
+	 * path which is enabled again in the following spin_unlock(). We have
+	 * one migrate_disable() pending in the slow-path which is reversed
+	 * after the raw_spin_unlock_irq() where we leave the atomic context.
+	 */
+	migrate_disable();
+
 	spin_unlock(q.lock_ptr);
 	/*
 	 * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
@@ -2854,6 +2875,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
 	 */
 	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
 	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
+	migrate_enable();
 
 	if (ret) {
 		if (ret == 1)
@@ -2999,10 +3021,19 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
 		 * rt_waiter. Also see the WARN in wake_futex_pi().
 		 */
 		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		/*
+		 * Magic trickery for now to make the RT migrate disable
+		 * logic happy. The following spin_unlock() happens with
+		 * interrupts disabled so the internal migrate_enable()
+		 * won't undo the migrate_disable() which was issued when
+		 * locking hb->lock.
+		 */
+		migrate_disable();
 		spin_unlock(&hb->lock);
 
 		/* drops pi_state->pi_mutex.wait_lock */
 		ret = wake_futex_pi(uaddr, uval, pi_state);
+		migrate_enable();
 
 		put_pi_state(pi_state);
 
@@ -3171,7 +3202,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	struct hrtimer_sleeper timeout, *to;
 	struct futex_pi_state *pi_state = NULL;
 	struct rt_mutex_waiter rt_waiter;
-	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;
@@ -3192,7 +3223,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	 * The waiter is allocated on our stack, manipulated by the requeue
 	 * code while we sleep on uaddr.
 	 */
-	rt_mutex_init_waiter(&rt_waiter);
+	rt_mutex_init_waiter(&rt_waiter, false);
 
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
 	if (unlikely(ret != 0))
@@ -3223,20 +3254,55 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 	/* 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;
+	/*
+	 * 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;
+	}
 
 	/*
-	 * 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) {
@@ -3245,7 +3311,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 		 * 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);
 			if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
 				pi_state = q.pi_state;
@@ -3256,7 +3323,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 			 * the requeue_pi() code acquired for us.
 			 */
 			put_pi_state(q.pi_state);
-			spin_unlock(q.lock_ptr);
+			spin_unlock(&hb2->lock);
 		}
 	} else {
 		struct rt_mutex *pi_mutex;
@@ -3270,7 +3337,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
 		pi_mutex = &q.pi_state->pi_mutex;
 		ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);
 
-		spin_lock(q.lock_ptr);
+		spin_lock(&hb2->lock);
+		BUG_ON(&hb2->lock != q.lock_ptr);
 		if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
 			ret = 0;
 
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 762a928e18f92..7929fcdb78174 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -192,10 +192,16 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
 {
 	irqreturn_t retval;
 	unsigned int flags = 0;
+	struct pt_regs *regs = get_irq_regs();
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 
 	retval = __handle_irq_event_percpu(desc, &flags);
 
-	add_interrupt_randomness(desc->irq_data.irq, flags);
+#ifdef CONFIG_PREEMPT_RT
+	desc->random_ip = ip;
+#else
+	add_interrupt_randomness(desc->irq_data.irq, flags, ip);
+#endif
 
 	if (!noirqdebug)
 		note_interrupt(desc, retval);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 5df903fccb609..110c4cced672e 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1175,6 +1175,12 @@ static int irq_thread(void *data)
 		if (action_ret == IRQ_WAKE_THREAD)
 			irq_wake_secondary(desc, action);
 
+#ifdef CONFIG_PREEMPT_RT
+		migrate_disable();
+		add_interrupt_randomness(action->irq, 0,
+				 desc->random_ip ^ (unsigned long) action);
+		migrate_enable();
+#endif
 		wake_threads_waitq(desc);
 	}
 
@@ -2711,7 +2717,7 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
  *	This call sets the internal irqchip state of an interrupt,
  *	depending on the value of @which.
  *
- *	This function should be called with preemption disabled if the
+ *	This function should be called with migration disabled if the
  *	interrupt controller has per-cpu registers.
  */
 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index f865e5f4d3825..dc7311dd74b11 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -443,6 +443,10 @@ MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 
 static int __init irqfixup_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT
+	pr_warn("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");
@@ -455,6 +459,10 @@ module_param(irqfixup, int, 0644);
 
 static int __init irqpoll_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT
+	pr_warn("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");
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index eca83965b631a..8183d30e1bb1c 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -18,6 +18,7 @@
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/smp.h>
+#include <linux/interrupt.h>
 #include <asm/processor.h>
 
 
@@ -52,13 +53,19 @@ void __weak arch_irq_work_raise(void)
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
+	struct llist_head *list;
+	bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT);
+
+	lazy_work = atomic_read(&work->flags) & IRQ_WORK_LAZY;
+
 	/* If the work is "lazy", handle it from next tick if any */
-	if (atomic_read(&work->flags) & IRQ_WORK_LAZY) {
-		if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
-		    tick_nohz_tick_stopped())
-			arch_irq_work_raise();
-	} else {
-		if (llist_add(&work->llnode, this_cpu_ptr(&raised_list)))
+	if (lazy_work || (realtime && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)))
+		list = this_cpu_ptr(&lazy_list);
+	else
+		list = this_cpu_ptr(&raised_list);
+
+	if (llist_add(&work->llnode, list)) {
+		if (!lazy_work || tick_nohz_tick_stopped())
 			arch_irq_work_raise();
 	}
 }
@@ -102,7 +109,13 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
 	if (cpu != smp_processor_id()) {
 		/* Arch remote IPI send/receive backend aren't NMI safe */
 		WARN_ON_ONCE(in_nmi());
-		__smp_call_single_queue(cpu, &work->llnode);
+
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)) {
+			if (llist_add(&work->llnode, &per_cpu(lazy_list, cpu)))
+				arch_send_call_function_single_ipi(cpu);
+		} else {
+			__smp_call_single_queue(cpu, &work->llnode);
+		}
 	} else {
 		__irq_work_queue_local(work);
 	}
@@ -120,9 +133,8 @@ bool irq_work_needs_cpu(void)
 	raised = this_cpu_ptr(&raised_list);
 	lazy = this_cpu_ptr(&lazy_list);
 
-	if (llist_empty(raised) || arch_irq_work_has_interrupt())
-		if (llist_empty(lazy))
-			return false;
+	if (llist_empty(raised) && llist_empty(lazy))
+		return false;
 
 	/* All work should have been flushed before going offline */
 	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
@@ -160,8 +172,12 @@ static void irq_work_run_list(struct llist_head *list)
 	struct irq_work *work, *tmp;
 	struct llist_node *llnode;
 
+#ifndef CONFIG_PREEMPT_RT
+	/*
+	 * nort: On RT IRQ-work may run in SOFTIRQ context.
+	 */
 	BUG_ON(!irqs_disabled());
-
+#endif
 	if (llist_empty(list))
 		return;
 
@@ -177,7 +193,16 @@ static void irq_work_run_list(struct llist_head *list)
 void irq_work_run(void)
 {
 	irq_work_run_list(this_cpu_ptr(&raised_list));
-	irq_work_run_list(this_cpu_ptr(&lazy_list));
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		/*
+		 * NOTE: we raise softirq via IPI for safety,
+		 * and execute in irq_work_tick() to move the
+		 * overhead from hard to soft irq context.
+		 */
+		if (!llist_empty(this_cpu_ptr(&lazy_list)))
+			raise_softirq(TIMER_SOFTIRQ);
+	} else
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
 }
 EXPORT_SYMBOL_GPL(irq_work_run);
 
@@ -187,8 +212,17 @@ void irq_work_tick(void)
 
 	if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
 		irq_work_run_list(raised);
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
+}
+
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+void irq_work_tick_soft(void)
+{
 	irq_work_run_list(this_cpu_ptr(&lazy_list));
 }
+#endif
 
 /*
  * Synchronize against the irq_work @entry, ensures the entry is not
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c19c0dad1ebef..c85754463de6d 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -978,7 +978,6 @@ void crash_kexec(struct pt_regs *regs)
 	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
 	if (old_cpu == PANIC_CPU_INVALID) {
 		/* This is the 1st CPU which comes here, so go ahead. */
-		printk_safe_flush_on_panic();
 		__crash_kexec(regs);
 
 		/*
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 35859da8bd4f7..dfff31ed644a6 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -138,6 +138,15 @@ KERNEL_ATTR_RO(vmcoreinfo);
 
 #endif /* CONFIG_CRASH_CORE */
 
+#if defined(CONFIG_PREEMPT_RT)
+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)
@@ -228,6 +237,9 @@ static struct attribute * kernel_attrs[] = {
 #ifndef CONFIG_TINY_RCU
 	&rcu_expedited_attr.attr,
 	&rcu_normal_attr.attr,
+#endif
+#ifdef CONFIG_PREEMPT_RT
+	&realtime_attr.attr,
 #endif
 	NULL
 };
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 6d11cfb9b41f2..c7fbf737e16ea 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -3,7 +3,7 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT		:= n
 
-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+obj-y += semaphore.o rwsem.o percpu-rwsem.o
 
 # Avoid recursion lockdep -> KCSAN -> ... -> lockdep.
 KCSAN_SANITIZE_lockdep.o := n
@@ -15,19 +15,23 @@ CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
 endif
 
-obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
 obj-$(CONFIG_LOCKDEP) += lockdep.o
 ifeq ($(CONFIG_PROC_FS),y)
 obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
 endif
 obj-$(CONFIG_SMP) += spinlock.o
-obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
+ifneq ($(CONFIG_PREEMPT_RT),y)
+obj-y += mutex.o
+obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
+obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+endif
+obj-$(CONFIG_PREEMPT_RT) += mutex-rt.o rwsem-rt.o rwlock-rt.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
 obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
 obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 54b74fabf40c7..46fc7b2be72c7 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4113,7 +4113,7 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
 	 */
 	for (depth = curr->lockdep_depth - 1; depth >= 0; depth--) {
 		struct held_lock *prev = curr->held_locks + depth;
-		if (prev->irq_context != next->irq_context)
+		if (prev->check && prev->irq_context != next->irq_context)
 			break;
 	}
 	depth++;
@@ -4124,6 +4124,9 @@ static int check_wait_context(struct task_struct *curr, struct held_lock *next)
 		struct held_lock *prev = curr->held_locks + depth;
 		short prev_inner = hlock_class(prev)->wait_type_inner;
 
+		if (!prev->check)
+			continue;
+
 		if (prev_inner) {
 			/*
 			 * We can have a bigger inner than a previous one
@@ -4881,6 +4884,7 @@ static void check_flags(unsigned long flags)
 		}
 	}
 
+#ifndef CONFIG_PREEMPT_RT
 	/*
 	 * We dont accurately track softirq state in e.g.
 	 * hardirq contexts (such as on 4KSTACKS), so only
@@ -4895,6 +4899,7 @@ static void check_flags(unsigned long flags)
 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
 		}
 	}
+#endif
 
 	if (!debug_locks)
 		print_irqtrace_events(current);
diff --git a/kernel/locking/mutex-rt.c b/kernel/locking/mutex-rt.c
new file mode 100644
index 0000000000000..5d418dc9ac701
--- /dev/null
+++ b/kernel/locking/mutex-rt.c
@@ -0,0 +1,223 @@
+/*
+ * 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_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock);
+
+void __lockfunc _mutex_lock_io(struct mutex *lock)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	_mutex_lock(lock);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io);
+
+int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	ret = __rt_mutex_lock_state(&lock->lock, TASK_INTERRUPTIBLE);
+	if (ret)
+		mutex_release(&lock->dep_map, _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_state(&lock->lock, TASK_KILLABLE);
+	if (ret)
+		mutex_release(&lock->dep_map, _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_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock_nested);
+
+void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass)
+{
+	int token;
+
+	token = io_schedule_prepare();
+
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io_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_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+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_state(&lock->lock, TASK_INTERRUPTIBLE);
+	if (ret)
+		mutex_release(&lock->dep_map, _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_state(&lock->lock, TASK_KILLABLE);
+	if (ret)
+		mutex_release(&lock->dep_map, _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, _RET_IP_);
+	__rt_mutex_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_unlock);
+
+/**
+ * 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);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index cfdd5b93264d7..ddd0508b0237a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -8,6 +8,11 @@
  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
  *  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/locking/rt-mutex-design.rst for details.
  */
@@ -19,6 +24,8 @@
 #include <linux/sched/wake_q.h>
 #include <linux/sched/debug.h>
 #include <linux/timer.h>
+#include <linux/ww_mutex.h>
+#include <linux/blkdev.h>
 
 #include "rtmutex_common.h"
 
@@ -136,6 +143,12 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
 		WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
+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 there's no debugging state to be
  * set up.
@@ -227,7 +240,7 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
  * Only use with rt_mutex_waiter_{less,equal}()
  */
 #define task_to_waiter(p)	\
-	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
+	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline, .task = (p) }
 
 static inline int
 rt_mutex_waiter_less(struct rt_mutex_waiter *left,
@@ -267,6 +280,27 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
 	return 1;
 }
 
+#define STEAL_NORMAL  0
+#define STEAL_LATERAL 1
+
+static inline int
+rt_mutex_steal(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, int mode)
+{
+	struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock);
+
+	if (waiter == top_waiter || rt_mutex_waiter_less(waiter, top_waiter))
+		return 1;
+
+	/*
+	 * Note that RT tasks are excluded from lateral-steals
+	 * to prevent the introduction of an unbounded latency.
+	 */
+	if (mode == STEAL_NORMAL || rt_task(waiter->task))
+		return 0;
+
+	return rt_mutex_waiter_equal(waiter, top_waiter);
+}
+
 static void
 rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
@@ -371,6 +405,14 @@ static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
 	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
 }
 
+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:
  */
@@ -378,7 +420,8 @@ int max_lock_depth = 1024;
 
 static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
 {
-	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+	return rt_mutex_real_waiter(p->pi_blocked_on) ?
+		p->pi_blocked_on->lock : NULL;
 }
 
 /*
@@ -514,7 +557,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * 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;
 
 	/*
@@ -694,13 +737,16 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * follow here. This is the end of the chain we are walking.
 	 */
 	if (!rt_mutex_owner(lock)) {
+		struct rt_mutex_waiter *lock_top_waiter;
+
 		/*
 		 * If the requeue [7] above changed the top waiter,
 		 * then we need to wake the new top waiter up to try
 		 * to get the lock.
 		 */
-		if (prerequeue_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 (prerequeue_top_waiter != lock_top_waiter)
+			rt_mutex_wake_waiter(lock_top_waiter);
 		raw_spin_unlock_irq(&lock->wait_lock);
 		return 0;
 	}
@@ -801,9 +847,11 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
  * @task:   The task which wants to acquire the lock
  * @waiter: The waiter that is queued to the lock's wait tree if the
  *	    callsite called task_blocked_on_lock(), otherwise NULL
+ * @mode:   Lock steal mode (STEAL_NORMAL, STEAL_LATERAL)
  */
-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)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -839,12 +887,11 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 	 */
 	if (waiter) {
 		/*
-		 * If waiter is not the highest priority waiter of
-		 * @lock, give up.
+		 * If waiter is not the highest priority waiter of @lock,
+		 * or its peer when lateral steal is allowed, give up.
 		 */
-		if (waiter != rt_mutex_top_waiter(lock))
+		if (!rt_mutex_steal(lock, waiter, mode))
 			return 0;
-
 		/*
 		 * We can acquire the lock. Remove the waiter from the
 		 * lock waiters tree.
@@ -862,14 +909,12 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 		 */
 		if (rt_mutex_has_waiters(lock)) {
 			/*
-			 * If @task->prio is greater than or equal to
-			 * the top waiter priority (kernel view),
-			 * @task lost.
+			 * If @task->prio is greater than the top waiter
+			 * priority (kernel view), or equal to it when a
+			 * lateral steal is forbidden, @task lost.
 			 */
-			if (!rt_mutex_waiter_less(task_to_waiter(task),
-						  rt_mutex_top_waiter(lock)))
+			if (!rt_mutex_steal(lock, task_to_waiter(task), mode))
 				return 0;
-
 			/*
 			 * The current top waiter stays enqueued. We
 			 * don't have to change anything in the lock
@@ -916,6 +961,344 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
 	return 1;
 }
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * preemptible spin_lock functions:
+ */
+static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
+					 void  (*slowfn)(struct rt_mutex *lock))
+{
+	might_sleep_no_state_check();
+
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return;
+	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_release(lock, current, NULL)))
+		return;
+	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
+
+static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+				   struct rt_mutex_waiter *waiter,
+				   struct task_struct *task,
+				   enum rtmutex_chainwalk chwalk);
+/*
+ * 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.
+ */
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags)
+{
+	struct task_struct *lock_owner, *self = current;
+	struct rt_mutex_waiter *top_waiter;
+	int ret;
+
+	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL))
+		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().
+	 */
+	raw_spin_lock(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+	raw_spin_unlock(&self->pi_lock);
+
+	ret = task_blocks_on_rt_mutex(lock, waiter, self, RT_MUTEX_MIN_CHAINWALK);
+	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_irqrestore(&lock->wait_lock, flags);
+
+		debug_rt_mutex_print_deadlock(waiter);
+
+		if (top_waiter != waiter || adaptive_wait(lock, lock_owner))
+			schedule();
+
+		raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+		raw_spin_lock(&self->pi_lock);
+		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+		raw_spin_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.
+	 */
+	raw_spin_lock(&self->pi_lock);
+	__set_current_state_no_track(self->saved_state);
+	self->saved_state = TASK_RUNNING;
+	raw_spin_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(!RB_EMPTY_NODE(&waiter->tree_entry));
+}
+
+static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+{
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
+
+	rt_mutex_init_waiter(&waiter, true);
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	rt_spin_lock_slowlock_locked(lock, &waiter, flags);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	debug_rt_mutex_free_waiter(&waiter);
+}
+
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+					     struct wake_q_head *wake_q,
+					     struct wake_q_head *wq_sleeper);
+/*
+ * Slow path to release a rt_mutex spin_lock style
+ */
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+{
+	unsigned long flags;
+	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
+	bool postunlock;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	postunlock = __rt_mutex_unlock_common(lock, &wake_q, &wake_sleeper_q);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	if (postunlock)
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+}
+
+void __lockfunc rt_spin_lock(spinlock_t *lock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
+{
+	rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+}
+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, _RET_IP_);
+	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+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_lock_unlock(spinlock_t *lock)
+{
+	spin_lock(lock);
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_lock_unlock);
+
+int __lockfunc rt_spin_trylock(spinlock_t *lock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = __rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	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) {
+		sleeping_lock_inc();
+		rcu_read_lock();
+		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;
+	ret = __rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		sleeping_lock_inc();
+		rcu_read_lock();
+		migrate_disable();
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_irqsave);
+
+void
+__rt_spin_lock_init(spinlock_t *lock, 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 *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+
+#endif /* PREEMPT_RT */
+
+#ifdef CONFIG_PREEMPT_RT
+	static inline int __sched
+__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
+	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
+
+	if (!hold_ctx)
+		return 0;
+
+	if (unlikely(ctx == hold_ctx))
+		return -EALREADY;
+
+	if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
+	    (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
+#ifdef CONFIG_DEBUG_MUTEXES
+		DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
+		ctx->contending_lock = ww;
+#endif
+		return -EDEADLK;
+	}
+
+	return 0;
+}
+#else
+	static inline int __sched
+__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	BUG();
+	return 0;
+}
+
+#endif
+
+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.
  *
@@ -948,6 +1331,22 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 		return -EDEADLK;
 
 	raw_spin_lock(&task->pi_lock);
+	/*
+	 * 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(&task->pi_lock);
+		return -EAGAIN;
+	}
+
+       BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
+
 	waiter->task = task;
 	waiter->lock = lock;
 	waiter->prio = task->prio;
@@ -971,7 +1370,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 		rt_mutex_enqueue_pi(owner, waiter);
 
 		rt_mutex_adjust_prio(owner);
-		if (owner->pi_blocked_on)
+		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
 	} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
 		chain_walk = 1;
@@ -1013,6 +1412,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
  * Called with lock->wait_lock held and interrupts disabled.
  */
 static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+				    struct wake_q_head *wake_sleeper_q,
 				    struct rt_mutex *lock)
 {
 	struct rt_mutex_waiter *waiter;
@@ -1052,7 +1452,10 @@ static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
 	 * Pairs with preempt_enable() in rt_mutex_postunlock();
 	 */
 	preempt_disable();
-	wake_q_add(wake_q, waiter->task);
+	if (waiter->savestate)
+		wake_q_add_sleeper(wake_sleeper_q, waiter->task);
+	else
+		wake_q_add(wake_q, waiter->task);
 	raw_spin_unlock(&current->pi_lock);
 }
 
@@ -1067,7 +1470,7 @@ static void remove_waiter(struct rt_mutex *lock,
 {
 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
 	struct task_struct *owner = rt_mutex_owner(lock);
-	struct rt_mutex *next_lock;
+	struct rt_mutex *next_lock = NULL;
 
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1093,7 +1496,8 @@ static void remove_waiter(struct rt_mutex *lock,
 	rt_mutex_adjust_prio(owner);
 
 	/* Store the lock on which owner is blocked or NULL */
-	next_lock = task_blocked_on_lock(owner);
+	if (rt_mutex_real_waiter(owner->pi_blocked_on))
+		next_lock = task_blocked_on_lock(owner);
 
 	raw_spin_unlock(&owner->pi_lock);
 
@@ -1129,26 +1533,28 @@ void rt_mutex_adjust_pi(struct task_struct *task)
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
 
 	waiter = task->pi_blocked_on;
-	if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+	if (!rt_mutex_real_waiter(waiter) ||
+	    rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 		return;
 	}
 	next_lock = waiter->lock;
-	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, RT_MUTEX_MIN_CHAINWALK, NULL,
 				   next_lock, NULL, task);
 }
 
-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
 {
 	debug_rt_mutex_init_waiter(waiter);
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
 	RB_CLEAR_NODE(&waiter->tree_entry);
 	waiter->task = NULL;
+	waiter->savestate = savestate;
 }
 
 /**
@@ -1164,7 +1570,8 @@ void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
 static int __sched
 __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		    struct hrtimer_sleeper *timeout,
-		    struct rt_mutex_waiter *waiter)
+		    struct rt_mutex_waiter *waiter,
+		    struct ww_acquire_ctx *ww_ctx)
 {
 	int ret = 0;
 
@@ -1173,16 +1580,17 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		if (try_to_take_rt_mutex(lock, current, waiter))
 			break;
 
-		/*
-		 * TASK_INTERRUPTIBLE checks for signals and
-		 * timeout. Ignored otherwise.
-		 */
-		if (likely(state == TASK_INTERRUPTIBLE)) {
-			/* Signal pending? */
-			if (signal_pending(current))
-				ret = -EINTR;
-			if (timeout && !timeout->task)
-				ret = -ETIMEDOUT;
+		if (timeout && !timeout->task) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (ww_ctx && ww_ctx->acquired > 0) {
+			ret = __mutex_lock_check_stamp(lock, ww_ctx);
 			if (ret)
 				break;
 		}
@@ -1221,19 +1629,157 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
 	}
 }
 
+static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
+						   struct ww_acquire_ctx *ww_ctx)
+{
+#ifdef CONFIG_DEBUG_MUTEXES
+	/*
+	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+	 * but released with a normal mutex_unlock in this call.
+	 *
+	 * This should never happen, always use ww_mutex_unlock.
+	 */
+	DEBUG_LOCKS_WARN_ON(ww->ctx);
+
+	/*
+	 * Not quite done after calling ww_acquire_done() ?
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+	if (ww_ctx->contending_lock) {
+		/*
+		 * After -EDEADLK you tried to
+		 * acquire a different ww_mutex? Bad!
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+		/*
+		 * You called ww_mutex_lock after receiving -EDEADLK,
+		 * but 'forgot' to unlock everything else first?
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+		ww_ctx->contending_lock = NULL;
+	}
+
+	/*
+	 * Naughty, using a different class will lead to undefined behavior!
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+	ww_ctx->acquired++;
+}
+
+#ifdef CONFIG_PREEMPT_RT
+static void ww_mutex_account_lock(struct rt_mutex *lock,
+				  struct ww_acquire_ctx *ww_ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
+	struct rt_mutex_waiter *waiter, *n;
+
+	/*
+	 * This branch gets optimized out for the common case,
+	 * and is only important for ww_mutex_lock.
+	 */
+	ww_mutex_lock_acquired(ww, ww_ctx);
+	ww->ctx = ww_ctx;
+
+	/*
+	 * Give any possible sleeping processes the chance to wake up,
+	 * so they can recheck if they have to back off.
+	 */
+	rbtree_postorder_for_each_entry_safe(waiter, n, &lock->waiters.rb_root,
+					     tree_entry) {
+		/* XXX debug rt mutex waiter wakeup */
+
+		BUG_ON(waiter->lock != lock);
+		rt_mutex_wake_waiter(waiter);
+	}
+}
+
+#else
+
+static void ww_mutex_account_lock(struct rt_mutex *lock,
+				  struct ww_acquire_ctx *ww_ctx)
+{
+	BUG();
+}
+#endif
+
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+				     struct hrtimer_sleeper *timeout,
+				     enum rtmutex_chainwalk chwalk,
+				     struct ww_acquire_ctx *ww_ctx,
+				     struct rt_mutex_waiter *waiter)
+{
+	int ret;
+
+#ifdef CONFIG_PREEMPT_RT
+	if (ww_ctx) {
+		struct ww_mutex *ww;
+
+		ww = container_of(lock, struct ww_mutex, base.lock);
+		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
+			return -EALREADY;
+	}
+#endif
+
+	/* Try to acquire the lock again: */
+	if (try_to_take_rt_mutex(lock, current, NULL)) {
+		if (ww_ctx)
+			ww_mutex_account_lock(lock, ww_ctx);
+		return 0;
+	}
+
+	set_current_state(state);
+
+	/* Setup the timer, when timeout != NULL */
+	if (unlikely(timeout))
+		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
+
+	ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
+
+	if (likely(!ret)) {
+		/* sleep on the mutex */
+		ret = __rt_mutex_slowlock(lock, state, timeout, waiter,
+					  ww_ctx);
+	} else if (ww_ctx) {
+		/* ww_mutex received EDEADLK, let it become EALREADY */
+		ret = __mutex_lock_check_stamp(lock, ww_ctx);
+		BUG_ON(!ret);
+	}
+
+	if (unlikely(ret)) {
+		__set_current_state(TASK_RUNNING);
+		remove_waiter(lock, waiter);
+		/* ww_mutex wants to report EDEADLK/EALREADY, let it */
+		if (!ww_ctx)
+			rt_mutex_handle_deadlock(ret, chwalk, waiter);
+	} else if (ww_ctx) {
+		ww_mutex_account_lock(lock, ww_ctx);
+	}
+
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit
+	 * unconditionally. We might have to fix that up.
+	 */
+	fixup_rt_mutex_waiters(lock);
+	return ret;
+}
+
 /*
  * Slow path lock function:
  */
 static int __sched
 rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		  struct hrtimer_sleeper *timeout,
-		  enum rtmutex_chainwalk chwalk)
+		  enum rtmutex_chainwalk chwalk,
+		  struct ww_acquire_ctx *ww_ctx)
 {
 	struct rt_mutex_waiter waiter;
 	unsigned long flags;
 	int ret = 0;
 
-	rt_mutex_init_waiter(&waiter);
+	rt_mutex_init_waiter(&waiter, false);
 
 	/*
 	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
@@ -1245,35 +1791,8 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 	 */
 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 
-	/* Try to acquire the lock again: */
-	if (try_to_take_rt_mutex(lock, current, NULL)) {
-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-		return 0;
-	}
-
-	set_current_state(state);
-
-	/* Setup the timer, when timeout != NULL */
-	if (unlikely(timeout))
-		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
-
-	ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
-
-	if (likely(!ret))
-		/* sleep on the mutex */
-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
-
-	if (unlikely(ret)) {
-		__set_current_state(TASK_RUNNING);
-		remove_waiter(lock, &waiter);
-		rt_mutex_handle_deadlock(ret, chwalk, &waiter);
-	}
-
-	/*
-	 * try_to_take_rt_mutex() sets the waiter bit
-	 * unconditionally. We might have to fix that up.
-	 */
-	fixup_rt_mutex_waiters(lock);
+	ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, ww_ctx,
+				       &waiter);
 
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
@@ -1334,7 +1853,8 @@ static inline int rt_mutex_slowtrylock(struct rt_mutex *lock)
  * Return whether the current task needs to call rt_mutex_postunlock().
  */
 static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
-					struct wake_q_head *wake_q)
+					struct wake_q_head *wake_q,
+					struct wake_q_head *wake_sleeper_q)
 {
 	unsigned long flags;
 
@@ -1388,7 +1908,7 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
 	 *
 	 * Queue the next waiter for wakeup once we release the wait_lock.
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	mark_wakeup_next_waiter(wake_q, wake_sleeper_q, lock);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return true; /* call rt_mutex_postunlock() */
@@ -1402,29 +1922,45 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
  */
 static inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
+		  struct ww_acquire_ctx *ww_ctx,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
-				enum rtmutex_chainwalk chwalk))
+				enum rtmutex_chainwalk chwalk,
+				struct ww_acquire_ctx *ww_ctx))
 {
 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
 		return 0;
 
-	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
+	/*
+	 * If rt_mutex blocks, the function sched_submit_work will not call
+	 * blk_schedule_flush_plug (because tsk_is_pi_blocked would be true).
+	 * We must call blk_schedule_flush_plug here, if we don't call it,
+	 * a deadlock in I/O may happen.
+	 */
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK, ww_ctx);
 }
 
 static inline int
 rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
 			struct hrtimer_sleeper *timeout,
 			enum rtmutex_chainwalk chwalk,
+			struct ww_acquire_ctx *ww_ctx,
 			int (*slowfn)(struct rt_mutex *lock, int state,
 				      struct hrtimer_sleeper *timeout,
-				      enum rtmutex_chainwalk chwalk))
+				      enum rtmutex_chainwalk chwalk,
+				      struct ww_acquire_ctx *ww_ctx))
 {
 	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
 	    likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
 		return 0;
 
-	return slowfn(lock, state, timeout, chwalk);
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	return slowfn(lock, state, timeout, chwalk, ww_ctx);
 }
 
 static inline int
@@ -1440,9 +1976,11 @@ rt_mutex_fasttrylock(struct rt_mutex *lock,
 /*
  * Performs the wakeup of the the top-waiter and re-enables preemption.
  */
-void rt_mutex_postunlock(struct wake_q_head *wake_q)
+void rt_mutex_postunlock(struct wake_q_head *wake_q,
+			 struct wake_q_head *wake_sleeper_q)
 {
 	wake_up_q(wake_q);
+	wake_up_q_sleeper(wake_sleeper_q);
 
 	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
 	preempt_enable();
@@ -1451,23 +1989,46 @@ void rt_mutex_postunlock(struct wake_q_head *wake_q)
 static inline void
 rt_mutex_fastunlock(struct rt_mutex *lock,
 		    bool (*slowfn)(struct rt_mutex *lock,
-				   struct wake_q_head *wqh))
+				   struct wake_q_head *wqh,
+				   struct wake_q_head *wq_sleeper))
 {
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 
 	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
 		return;
 
-	if (slowfn(lock, &wake_q))
-		rt_mutex_postunlock(&wake_q);
+	if (slowfn(lock, &wake_q, &wake_sleeper_q))
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+}
+
+int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+{
+	might_sleep();
+	return rt_mutex_fastlock(lock, state, NULL, rt_mutex_slowlock);
+}
+
+/**
+ * rt_mutex_lock_state - lock a rt_mutex with a given state
+ *
+ * @lock:      The rt_mutex to be locked
+ * @state:     The state to set when blocking on the rt_mutex
+ */
+static inline int __sched rt_mutex_lock_state(struct rt_mutex *lock,
+					      unsigned int subclass, int state)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	ret = __rt_mutex_lock_state(lock, state);
+	if (ret)
+		mutex_release(&lock->dep_map, _RET_IP_);
+	return ret;
 }
 
 static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
 {
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
+	rt_mutex_lock_state(lock, subclass, TASK_UNINTERRUPTIBLE);
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -1508,16 +2069,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
 {
-	int ret;
-
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	ret = rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
-	if (ret)
-		mutex_release(&lock->dep_map, _RET_IP_);
-
-	return ret;
+	return rt_mutex_lock_state(lock, 0, TASK_INTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
@@ -1534,6 +2086,22 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
 	return __rt_mutex_slowtrylock(lock);
 }
 
+/**
+ * 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
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
+{
+	return rt_mutex_lock_state(lock, 0, TASK_KILLABLE);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
 /**
  * rt_mutex_timed_lock - lock a rt_mutex interruptible
  *			the timeout structure is provided
@@ -1557,6 +2125,7 @@ rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
 	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
 				       RT_MUTEX_MIN_CHAINWALK,
+				       NULL,
 				       rt_mutex_slowlock);
 	if (ret)
 		mutex_release(&lock->dep_map, _RET_IP_);
@@ -1565,6 +2134,18 @@ rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
 }
 EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
 
+int __sched __rt_mutex_trylock(struct rt_mutex *lock)
+{
+#ifdef CONFIG_PREEMPT_RT
+	if (WARN_ON_ONCE(in_irq() || in_nmi()))
+#else
+	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+#endif
+		return 0;
+
+	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+}
+
 /**
  * rt_mutex_trylock - try to lock a rt_mutex
  *
@@ -1580,10 +2161,7 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
 {
 	int ret;
 
-	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
-		return 0;
-
-	ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+	ret = __rt_mutex_trylock(lock);
 	if (ret)
 		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 
@@ -1591,6 +2169,11 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
 }
 EXPORT_SYMBOL_GPL(rt_mutex_trylock);
 
+void __sched __rt_mutex_unlock(struct rt_mutex *lock)
+{
+	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+}
+
 /**
  * rt_mutex_unlock - unlock a rt_mutex
  *
@@ -1599,16 +2182,13 @@ EXPORT_SYMBOL_GPL(rt_mutex_trylock);
 void __sched rt_mutex_unlock(struct rt_mutex *lock)
 {
 	mutex_release(&lock->dep_map, _RET_IP_);
-	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+	__rt_mutex_unlock(lock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_unlock);
 
-/**
- * Futex variant, that since futex variants do not use the fast-path, can be
- * simple and will not need to retry.
- */
-bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				    struct wake_q_head *wake_q)
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+					     struct wake_q_head *wake_q,
+					     struct wake_q_head *wq_sleeper)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1625,23 +2205,35 @@ bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
 	 * avoid inversion prior to the wakeup.  preempt_disable()
 	 * therein pairs with rt_mutex_postunlock().
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	mark_wakeup_next_waiter(wake_q, wq_sleeper, lock);
 
 	return true; /* call postunlock() */
 }
 
+/**
+ * Futex variant, that since futex variants do not use the fast-path, can be
+ * simple and will not need to retry.
+ */
+bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
+				     struct wake_q_head *wake_q,
+				     struct wake_q_head *wq_sleeper)
+{
+	return __rt_mutex_unlock_common(lock, wake_q, wq_sleeper);
+}
+
 void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
 {
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 	unsigned long flags;
 	bool postunlock;
 
 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
-	postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
+	postunlock = __rt_mutex_futex_unlock(lock, &wake_q, &wake_sleeper_q);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	if (postunlock)
-		rt_mutex_postunlock(&wake_q);
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
 }
 
 /**
@@ -1680,7 +2272,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name,
 	if (name && key)
 		debug_rt_mutex_init(lock, name, key);
 }
-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
@@ -1700,6 +2292,14 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				struct task_struct *proxy_owner)
 {
 	__rt_mutex_init(lock, NULL, NULL);
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/*
+	 * get another key class for the wait_lock. LOCK_PI and UNLOCK_PI is
+	 * holding the ->wait_lock of the proxy_lock while unlocking a sleeping
+	 * lock.
+	 */
+	raw_spin_lock_init(&lock->wait_lock);
+#endif
 	debug_rt_mutex_proxy_lock(lock, proxy_owner);
 	rt_mutex_set_owner(lock, proxy_owner);
 }
@@ -1723,6 +2323,26 @@ void rt_mutex_proxy_unlock(struct rt_mutex *lock,
 	rt_mutex_set_owner(lock, NULL);
 }
 
+static void fixup_rt_mutex_blocked(struct rt_mutex *lock)
+{
+	struct task_struct *tsk = current;
+	/*
+	 * RT has a problem here when the wait got interrupted by a timeout
+	 * or a signal. task->pi_blocked_on is still set. The task must
+	 * acquire the hash bucket lock when returning from this function.
+	 *
+	 * If the hash bucket lock is contended then the
+	 * BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on)) in
+	 * task_blocks_on_rt_mutex() will trigger. This can be avoided by
+	 * clearing task->pi_blocked_on which removes the task from the
+	 * boosting chain of the rtmutex. That's correct because the task
+	 * is not longer blocked on it.
+	 */
+	raw_spin_lock(&tsk->pi_lock);
+	tsk->pi_blocked_on = NULL;
+	raw_spin_unlock(&tsk->pi_lock);
+}
+
 /**
  * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
  * @lock:		the rt_mutex to take
@@ -1753,6 +2373,34 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 	if (try_to_take_rt_mutex(lock, task, NULL))
 		return 1;
 
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * 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(&task->pi_lock);
+	if (task->pi_blocked_on) {
+		raw_spin_unlock(&task->pi_lock);
+		return -EAGAIN;
+	}
+	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
+	raw_spin_unlock(&task->pi_lock);
+#endif
+
 	/* We enforce deadlock detection for futexes */
 	ret = task_blocks_on_rt_mutex(lock, waiter, task,
 				      RT_MUTEX_FULL_CHAINWALK);
@@ -1767,6 +2415,9 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 		ret = 0;
 	}
 
+	if (ret)
+		fixup_rt_mutex_blocked(lock);
+
 	debug_rt_mutex_print_deadlock(waiter);
 
 	return ret;
@@ -1852,12 +2503,15 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
 	raw_spin_lock_irq(&lock->wait_lock);
 	/* sleep on the mutex */
 	set_current_state(TASK_INTERRUPTIBLE);
-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
+	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
 	 * have to fix that up.
 	 */
 	fixup_rt_mutex_waiters(lock);
+	if (ret)
+		fixup_rt_mutex_blocked(lock);
+
 	raw_spin_unlock_irq(&lock->wait_lock);
 
 	return ret;
@@ -1919,3 +2573,97 @@ bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
 
 	return cleanup;
 }
+
+static inline int
+ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+	unsigned tmp;
+
+	if (ctx->deadlock_inject_countdown-- == 0) {
+		tmp = ctx->deadlock_inject_interval;
+		if (tmp > UINT_MAX/4)
+			tmp = UINT_MAX;
+		else
+			tmp = tmp*2 + tmp + tmp/2;
+
+		ctx->deadlock_inject_interval = tmp;
+		ctx->deadlock_inject_countdown = tmp;
+		ctx->contending_lock = lock;
+
+		ww_mutex_unlock(lock);
+
+		return -EDEADLK;
+	}
+#endif
+
+	return 0;
+}
+
+#ifdef CONFIG_PREEMPT_RT
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+
+	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
+			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
+	ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0,
+				ctx);
+	if (ret)
+		mutex_release(&lock->base.dep_map, _RET_IP_);
+	else if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
+
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+
+	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
+			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
+	ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0,
+				ctx);
+	if (ret)
+		mutex_release(&lock->base.dep_map, _RET_IP_);
+	else if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock);
+
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+	/*
+	 * The unlocking fastpath is the 0->1 transition from 'locked'
+	 * into 'unlocked' state:
+	 */
+	if (lock->ctx) {
+#ifdef CONFIG_DEBUG_MUTEXES
+		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+		if (lock->ctx->acquired > 0)
+			lock->ctx->acquired--;
+		lock->ctx = NULL;
+	}
+
+	mutex_release(&lock->base.dep_map, _RET_IP_);
+	__rt_mutex_unlock(&lock->base.lock);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
+
+int __rt_mutex_owner_current(struct rt_mutex *lock)
+{
+	return rt_mutex_owner(lock) == current;
+}
+EXPORT_SYMBOL(__rt_mutex_owner_current);
+#endif
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index d1d62f942be22..546aaf058b9ec 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -15,6 +15,7 @@
 
 #include <linux/rtmutex.h>
 #include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
 
 /*
  * This is the control structure for tasks blocked on a rt_mutex,
@@ -29,6 +30,7 @@ struct rt_mutex_waiter {
 	struct rb_node          pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
+	bool			savestate;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
@@ -130,12 +132,15 @@ enum rtmutex_chainwalk {
 /*
  * 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);
 extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
 				  struct task_struct *proxy_owner);
-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
+extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savetate);
 extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 				     struct rt_mutex_waiter *waiter,
 				     struct task_struct *task);
@@ -153,9 +158,27 @@ extern int __rt_mutex_futex_trylock(struct rt_mutex *l);
 
 extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
 extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				 struct wake_q_head *wqh);
+				 struct wake_q_head *wqh,
+				 struct wake_q_head *wq_sleeper);
 
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
+				struct wake_q_head *wake_sleeper_q);
+
+/* RW semaphore special interface */
+struct ww_acquire_ctx;
+
+extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+extern int __rt_mutex_trylock(struct rt_mutex *lock);
+extern void __rt_mutex_unlock(struct rt_mutex *lock);
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+				     struct hrtimer_sleeper *timeout,
+				     enum rtmutex_chainwalk chwalk,
+				     struct ww_acquire_ctx *ww_ctx,
+				     struct rt_mutex_waiter *waiter);
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags);
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock);
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # include "rtmutex-debug.h"
diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
new file mode 100644
index 0000000000000..3ccfbc432942d
--- /dev/null
+++ b/kernel/locking/rwlock-rt.c
@@ -0,0 +1,384 @@
+/*
+ */
+#include <linux/sched/debug.h>
+#include <linux/export.h>
+
+#include "rtmutex_common.h"
+#include <linux/rwlock_types_rt.h>
+
+/*
+ * RT-specific reader/writer locks
+ *
+ * write_lock()
+ *  1) Lock lock->rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical region
+ *  4) Mark it write locked
+ *
+ * write_unlock()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS so readers can use the fast path again
+ *  3) Unlock lock->rtmutex to release blocked readers
+ *
+ * read_lock()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take lock->rtmutex.wait_lock which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on lock->rtmutex
+ *  5) unlock lock->rtmutex, goto 1)
+ *
+ * read_unlock()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in write_lock()#3
+ *
+ * read_lock()#3 has the consequence, that rw locks on RT are not writer
+ * fair, but writers, which should be avoided in RT tasks (think tasklist
+ * lock), are subject to the rtmutex priority/DL inheritance mechanism.
+ *
+ * It's possible to make the rw locks writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers
+ * to block on the rtmutex, but the rtmutex would have to be proxy locked
+ * for one reader after the other. We can't use multi-reader inheritance
+ * because there is no way to support that with
+ * SCHED_DEADLINE. Implementing the one by one reader boosting/handover
+ * mechanism is a major surgery for a very dubious value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ */
+
+void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
+			     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held semaphore:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+	atomic_set(&lock->readers, READER_BIAS);
+	rt_mutex_init(&lock->rtmutex);
+	lock->rtmutex.save_state = 1;
+}
+
+int __read_rt_trylock(struct rt_rw_lock *lock)
+{
+	int r, old;
+
+	/*
+	 * Increment reader count, if lock->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&lock->readers); r < 0;) {
+		old = atomic_cmpxchg(&lock->readers, r, r + 1);
+		if (likely(old == r))
+			return 1;
+		r = old;
+	}
+	return 0;
+}
+
+void __sched __read_rt_lock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
+
+	if (__read_rt_trylock(lock))
+		return;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	/*
+	 * Allow readers as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&lock->readers) != WRITER_BIAS) {
+		atomic_inc(&lock->readers);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			read_lock()
+	 *					write_lock()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * read_lock()
+	 * unlock(m->wait_lock)
+	 *			read_unlock()
+	 *			swake()
+	 *					lock(m->wait_lock)
+	 *					lock->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					write_unlock()
+	 *					lock->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			read_lock()
+	 *					write_lock()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call read_unlock() which might be unbound.
+	 */
+	rt_mutex_init_waiter(&waiter, true);
+	rt_spin_lock_slowlock_locked(m, &waiter, flags);
+	/*
+	 * The slowlock() above is guaranteed to return with the rtmutex is
+	 * now held, so there can't be a writer active. Increment the reader
+	 * count and immediately drop the rtmutex again.
+	 */
+	atomic_inc(&lock->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	rt_spin_lock_slowunlock(m);
+
+	debug_rt_mutex_free_waiter(&waiter);
+}
+
+void __read_rt_unlock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct task_struct *tsk;
+
+	/*
+	 * sem->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical region.
+	 */
+	if (!atomic_dec_and_test(&lock->readers))
+		return;
+
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path, but to clean up the rw
+	 * lock it needs to acquire m->wait_lock. The worst case which can
+	 * happen is a spurious wakeup.
+	 */
+	tsk = rt_mutex_owner(m);
+	if (tsk)
+		wake_up_process(tsk);
+
+	raw_spin_unlock_irq(&m->wait_lock);
+}
+
+static void __write_unlock_common(struct rt_rw_lock *lock, int bias,
+				  unsigned long flags)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+
+	atomic_add(READER_BIAS - bias, &lock->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	rt_spin_lock_slowunlock(m);
+}
+
+void __sched __write_rt_lock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct task_struct *self = current;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	__rt_spin_lock(m);
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &lock->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+
+	raw_spin_lock(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+	raw_spin_unlock(&self->pi_lock);
+
+	for (;;) {
+		/* Have all readers left the critical region? */
+		if (!atomic_read(&lock->readers)) {
+			atomic_set(&lock->readers, WRITER_BIAS);
+			raw_spin_lock(&self->pi_lock);
+			__set_current_state_no_track(self->saved_state);
+			self->saved_state = TASK_RUNNING;
+			raw_spin_unlock(&self->pi_lock);
+			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+			return;
+		}
+
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+
+		if (atomic_read(&lock->readers) != 0)
+			schedule();
+
+		raw_spin_lock_irqsave(&m->wait_lock, flags);
+
+		raw_spin_lock(&self->pi_lock);
+		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+		raw_spin_unlock(&self->pi_lock);
+	}
+}
+
+int __write_rt_trylock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	unsigned long flags;
+
+	if (!__rt_mutex_trylock(m))
+		return 0;
+
+	atomic_sub(READER_BIAS, &lock->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	if (!atomic_read(&lock->readers)) {
+		atomic_set(&lock->readers, WRITER_BIAS);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return 1;
+	}
+	__write_unlock_common(lock, 0, flags);
+	return 0;
+}
+
+void __write_rt_unlock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	__write_unlock_common(lock, WRITER_BIAS, flags);
+}
+
+/* Map the reader biased implementation */
+static inline int do_read_rt_trylock(rwlock_t *rwlock)
+{
+	return __read_rt_trylock(rwlock);
+}
+
+static inline int do_write_rt_trylock(rwlock_t *rwlock)
+{
+	return __write_rt_trylock(rwlock);
+}
+
+static inline void do_read_rt_lock(rwlock_t *rwlock)
+{
+	__read_rt_lock(rwlock);
+}
+
+static inline void do_write_rt_lock(rwlock_t *rwlock)
+{
+	__write_rt_lock(rwlock);
+}
+
+static inline void do_read_rt_unlock(rwlock_t *rwlock)
+{
+	__read_rt_unlock(rwlock);
+}
+
+static inline void do_write_rt_unlock(rwlock_t *rwlock)
+{
+	__write_rt_unlock(rwlock);
+}
+
+static inline void do_rwlock_rt_init(rwlock_t *rwlock, const char *name,
+				     struct lock_class_key *key)
+{
+	__rwlock_biased_rt_init(rwlock, name, key);
+}
+
+int __lockfunc rt_read_can_lock(rwlock_t *rwlock)
+{
+	return  atomic_read(&rwlock->readers) < 0;
+}
+
+int __lockfunc rt_write_can_lock(rwlock_t *rwlock)
+{
+	return atomic_read(&rwlock->readers) == READER_BIAS;
+}
+
+/*
+ * The common functions which get wrapped into the rwlock API.
+ */
+int __lockfunc rt_read_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = do_read_rt_trylock(rwlock);
+	if (ret) {
+		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+int __lockfunc rt_write_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = do_write_rt_trylock(rwlock);
+	if (ret) {
+		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+void __lockfunc rt_read_lock(rwlock_t *rwlock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+	do_read_rt_lock(rwlock);
+}
+EXPORT_SYMBOL(rt_read_lock);
+
+void __lockfunc rt_write_lock(rwlock_t *rwlock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+	do_write_rt_lock(rwlock);
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+void __lockfunc rt_read_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	do_read_rt_unlock(rwlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+void __lockfunc rt_write_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, _RET_IP_);
+	do_write_rt_unlock(rwlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
+{
+	do_rwlock_rt_init(rwlock, name, key);
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
new file mode 100644
index 0000000000000..f518495bd6ccd
--- /dev/null
+++ b/kernel/locking/rwsem-rt.c
@@ -0,0 +1,302 @@
+/*
+ */
+#include <linux/blkdev.h>
+#include <linux/rwsem.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/signal.h>
+#include <linux/export.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * RT-specific reader/writer semaphores
+ *
+ * down_write()
+ *  1) Lock sem->rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical region
+ *  4) Mark it write locked
+ *
+ * up_write()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS so readers can use the fast path again
+ *  3) Unlock sem->rtmutex to release blocked readers
+ *
+ * down_read()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take sem->rtmutex.wait_lock which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on sem->rtmutex
+ *  5) unlock sem->rtmutex, goto 1)
+ *
+ * up_read()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in down_write()#3
+ *
+ * down_read()#3 has the consequence, that rw semaphores on RT are not writer
+ * fair, but writers, which should be avoided in RT tasks (think mmap_sem),
+ * are subject to the rtmutex priority/DL inheritance mechanism.
+ *
+ * It's possible to make the rw semaphores writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers to
+ * block on the rtmutex, but the rtmutex would have to be proxy locked for one
+ * reader after the other. We can't use multi-reader inheritance because there
+ * is no way to support that with SCHED_DEADLINE. Implementing the one by one
+ * reader boosting/handover mechanism is a major surgery for a very dubious
+ * value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ */
+
+void __rwsem_init(struct rw_semaphore *sem, const char *name,
+		  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held semaphore:
+	 */
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
+	atomic_set(&sem->readers, READER_BIAS);
+}
+EXPORT_SYMBOL(__rwsem_init);
+
+int __down_read_trylock(struct rw_semaphore *sem)
+{
+	int r, old;
+
+	/*
+	 * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&sem->readers); r < 0;) {
+		old = atomic_cmpxchg(&sem->readers, r, r + 1);
+		if (likely(old == r))
+			return 1;
+		r = old;
+	}
+	return 0;
+}
+
+static int __sched __down_read_common(struct rw_semaphore *sem, int state)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	struct rt_mutex_waiter waiter;
+	int ret;
+
+	if (__down_read_trylock(sem))
+		return 0;
+	/*
+	 * If rt_mutex blocks, the function sched_submit_work will not call
+	 * blk_schedule_flush_plug (because tsk_is_pi_blocked would be true).
+	 * We must call blk_schedule_flush_plug here, if we don't call it,
+	 * a deadlock in I/O may happen.
+	 */
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	might_sleep();
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Allow readers as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&sem->readers) != WRITER_BIAS) {
+		atomic_inc(&sem->readers);
+		raw_spin_unlock_irq(&m->wait_lock);
+		return 0;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * down_read()
+	 * unlock(m->wait_lock)
+	 *			up_read()
+	 *			swake()
+	 *					lock(m->wait_lock)
+	 *					sem->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					up_write()
+	 *					sem->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call up_read() which might be unbound.
+	 */
+	rt_mutex_init_waiter(&waiter, false);
+	ret = rt_mutex_slowlock_locked(m, state, NULL, RT_MUTEX_MIN_CHAINWALK,
+				       NULL, &waiter);
+	/*
+	 * The slowlock() above is guaranteed to return with the rtmutex (for
+	 * ret = 0) is now held, so there can't be a writer active. Increment
+	 * the reader count and immediately drop the rtmutex again.
+	 * For ret != 0 we don't hold the rtmutex and need unlock the wait_lock.
+	 * We don't own the lock then.
+	 */
+	if (!ret)
+		atomic_inc(&sem->readers);
+	raw_spin_unlock_irq(&m->wait_lock);
+	if (!ret)
+		__rt_mutex_unlock(m);
+
+	debug_rt_mutex_free_waiter(&waiter);
+	return ret;
+}
+
+void __down_read(struct rw_semaphore *sem)
+{
+	int ret;
+
+	ret = __down_read_common(sem, TASK_UNINTERRUPTIBLE);
+	WARN_ON_ONCE(ret);
+}
+
+int __down_read_killable(struct rw_semaphore *sem)
+{
+	int ret;
+
+	ret = __down_read_common(sem, TASK_KILLABLE);
+	if (likely(!ret))
+		return ret;
+	WARN_ONCE(ret != -EINTR, "Unexpected state: %d\n", ret);
+	return -EINTR;
+}
+
+void __up_read(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	struct task_struct *tsk;
+
+	/*
+	 * sem->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical region.
+	 */
+	if (!atomic_dec_and_test(&sem->readers))
+		return;
+
+	might_sleep();
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path (due to a signal), but to
+	 * clean up the rwsem it needs to acquire m->wait_lock. The worst
+	 * case which can happen is a spurious wakeup.
+	 */
+	tsk = rt_mutex_owner(m);
+	if (tsk)
+		wake_up_process(tsk);
+
+	raw_spin_unlock_irq(&m->wait_lock);
+}
+
+static void __up_write_unlock(struct rw_semaphore *sem, int bias,
+			      unsigned long flags)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+
+	atomic_add(READER_BIAS - bias, &sem->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	__rt_mutex_unlock(m);
+}
+
+static int __sched __down_write_common(struct rw_semaphore *sem, int state)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	if (__rt_mutex_lock_state(m, state))
+		return -EINTR;
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &sem->readers);
+	might_sleep();
+
+	set_current_state(state);
+	for (;;) {
+		raw_spin_lock_irqsave(&m->wait_lock, flags);
+		/* Have all readers left the critical region? */
+		if (!atomic_read(&sem->readers)) {
+			atomic_set(&sem->readers, WRITER_BIAS);
+			__set_current_state(TASK_RUNNING);
+			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+			return 0;
+		}
+
+		if (signal_pending_state(state, current)) {
+			__set_current_state(TASK_RUNNING);
+			__up_write_unlock(sem, 0, flags);
+			return -EINTR;
+		}
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+
+		if (atomic_read(&sem->readers) != 0) {
+			schedule();
+			set_current_state(state);
+		}
+	}
+}
+
+void __sched __down_write(struct rw_semaphore *sem)
+{
+	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+int __sched __down_write_killable(struct rw_semaphore *sem)
+{
+	return __down_write_common(sem, TASK_KILLABLE);
+}
+
+int __down_write_trylock(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	if (!__rt_mutex_trylock(m))
+		return 0;
+
+	atomic_sub(READER_BIAS, &sem->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	if (!atomic_read(&sem->readers)) {
+		atomic_set(&sem->readers, WRITER_BIAS);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return 1;
+	}
+	__up_write_unlock(sem, 0, flags);
+	return 0;
+}
+
+void __up_write(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	__up_write_unlock(sem, WRITER_BIAS, flags);
+}
+
+void __downgrade_write(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	/* Release it and account current as reader */
+	__up_write_unlock(sem, WRITER_BIAS - 1, flags);
+}
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index f11b9bd3431d2..7f42a330709a9 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -28,6 +28,7 @@
 #include <linux/rwsem.h>
 #include <linux/atomic.h>
 
+#ifndef CONFIG_PREEMPT_RT
 #include "lock_events.h"
 
 /*
@@ -1332,6 +1333,7 @@ static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
 	return sem;
 }
 
+
 /*
  * lock for reading
  */
@@ -1482,6 +1484,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
 	if (tmp & RWSEM_FLAG_WAITERS)
 		rwsem_downgrade_wake(sem);
 }
+#endif
 
 /*
  * lock for reading
@@ -1617,7 +1620,9 @@ void down_read_non_owner(struct rw_semaphore *sem)
 {
 	might_sleep();
 	__down_read(sem);
+#ifndef CONFIG_PREEMPT_RT
 	__rwsem_set_reader_owned(sem, NULL);
+#endif
 }
 EXPORT_SYMBOL(down_read_non_owner);
 
@@ -1646,7 +1651,9 @@ EXPORT_SYMBOL(down_write_killable_nested);
 
 void up_read_non_owner(struct rw_semaphore *sem)
 {
+#ifndef CONFIG_PREEMPT_RT
 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
+#endif
 	__up_read(sem);
 }
 EXPORT_SYMBOL(up_read_non_owner);
diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
index 0ff08380f5318..45445a2f1799a 100644
--- a/kernel/locking/spinlock.c
+++ b/kernel/locking/spinlock.c
@@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)		\
  *         __[spin|read|write]_lock_bh()
  */
 BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT
 BUILD_LOCK_OPS(read, rwlock);
 BUILD_LOCK_OPS(write, rwlock);
+#endif
 
 #endif
 
@@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
 EXPORT_SYMBOL(_raw_spin_unlock_bh);
 #endif
 
+#ifndef CONFIG_PREEMPT_RT
+
 #ifndef CONFIG_INLINE_READ_TRYLOCK
 int __lockfunc _raw_read_trylock(rwlock_t *lock)
 {
@@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
 EXPORT_SYMBOL(_raw_write_unlock_bh);
 #endif
 
+#endif /* !PREEMPT_RT */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
index b9d93087ee669..72e306e0e8a3b 100644
--- a/kernel/locking/spinlock_debug.c
+++ b/kernel/locking/spinlock_debug.c
@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
 
 EXPORT_SYMBOL(__raw_spin_lock_init);
 
+#ifndef CONFIG_PREEMPT_RT
 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 char *name,
 }
 
 EXPORT_SYMBOL(__rwlock_init);
+#endif
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
@@ -139,6 +141,7 @@ void do_raw_spin_unlock(raw_spinlock_t *lock)
 	arch_spin_unlock(&lock->raw_lock);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 static void rwlock_bug(rwlock_t *lock, const char *msg)
 {
 	if (!debug_locks_off())
@@ -228,3 +231,5 @@ void do_raw_write_unlock(rwlock_t *lock)
 	debug_write_unlock(lock);
 	arch_write_unlock(&lock->raw_lock);
 }
+
+#endif
diff --git a/kernel/panic.c b/kernel/panic.c
index aef8872ba8435..d563542bc7eb1 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -247,7 +247,6 @@ void panic(const char *fmt, ...)
 	 * Bypass the panic_cpu check and call __crash_kexec directly.
 	 */
 	if (!_crash_kexec_post_notifiers) {
-		printk_safe_flush_on_panic();
 		__crash_kexec(NULL);
 
 		/*
@@ -271,8 +270,6 @@ void panic(const char *fmt, ...)
 	 */
 	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
 
-	/* Call flush even twice. It tries harder with a single online CPU */
-	printk_safe_flush_on_panic();
 	kmsg_dump(KMSG_DUMP_PANIC);
 
 	/*
@@ -542,9 +539,11 @@ static u64 oops_id;
 
 static int init_oops_id(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	if (!oops_id)
 		get_random_bytes(&oops_id, sizeof(oops_id));
 	else
+#endif
 		oops_id++;
 
 	return 0;
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 4d052fc6bcde7..7b219d824c0fb 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,4 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-y	= printk.o
-obj-$(CONFIG_PRINTK)	+= printk_safe.o
 obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
deleted file mode 100644
index 660f9a6bf73a1..0000000000000
--- a/kernel/printk/internal.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * internal.h - printk internal definitions
- */
-#include <linux/percpu.h>
-
-#ifdef CONFIG_PRINTK
-
-#define PRINTK_SAFE_CONTEXT_MASK	0x007ffffff
-#define PRINTK_NMI_DIRECT_CONTEXT_MASK	0x008000000
-#define PRINTK_NMI_CONTEXT_MASK		0xff0000000
-
-#define PRINTK_NMI_CONTEXT_OFFSET	0x010000000
-
-extern raw_spinlock_t logbuf_lock;
-
-__printf(5, 0)
-int vprintk_store(int facility, int level,
-		  const char *dict, size_t dictlen,
-		  const char *fmt, va_list args);
-
-__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
-__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args);
-void __printk_safe_enter(void);
-void __printk_safe_exit(void);
-
-void printk_safe_init(void);
-bool printk_percpu_data_ready(void);
-
-#define printk_safe_enter_irqsave(flags)	\
-	do {					\
-		local_irq_save(flags);		\
-		__printk_safe_enter();		\
-	} while (0)
-
-#define printk_safe_exit_irqrestore(flags)	\
-	do {					\
-		__printk_safe_exit();		\
-		local_irq_restore(flags);	\
-	} while (0)
-
-#define printk_safe_enter_irq()		\
-	do {					\
-		local_irq_disable();		\
-		__printk_safe_enter();		\
-	} while (0)
-
-#define printk_safe_exit_irq()			\
-	do {					\
-		__printk_safe_exit();		\
-		local_irq_enable();		\
-	} while (0)
-
-void defer_console_output(void);
-
-#else
-
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
-
-/*
- * In !PRINTK builds we still export logbuf_lock spin_lock, console_sem
- * semaphore and some of console functions (console_unlock()/etc.), so
- * printk-safe must preserve the existing local IRQ guarantees.
- */
-#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
-#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
-
-#define printk_safe_enter_irq() local_irq_disable()
-#define printk_safe_exit_irq() local_irq_enable()
-
-static inline void printk_safe_init(void) { }
-static inline bool printk_percpu_data_ready(void) { return false; }
-#endif /* CONFIG_PRINTK */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9b75f6bfc3333..8b74ff17b2eef 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -44,6 +44,9 @@
 #include <linux/irq_work.h>
 #include <linux/ctype.h>
 #include <linux/uio.h>
+#include <linux/kthread.h>
+#include <linux/clocksource.h>
+#include <linux/printk_ringbuffer.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
@@ -57,13 +60,13 @@
 
 #include "console_cmdline.h"
 #include "braille.h"
-#include "internal.h"
 
-int console_printk[4] = {
+int console_printk[5] = {
 	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
 	MESSAGE_LOGLEVEL_DEFAULT,	/* default_message_loglevel */
 	CONSOLE_LOGLEVEL_MIN,		/* minimum_console_loglevel */
 	CONSOLE_LOGLEVEL_DEFAULT,	/* default_console_loglevel */
+	CONSOLE_LOGLEVEL_EMERGENCY,	/* emergency_console_loglevel */
 };
 EXPORT_SYMBOL_GPL(console_printk);
 
@@ -224,19 +227,7 @@ static int nr_ext_console_drivers;
 
 static int __down_trylock_console_sem(unsigned long ip)
 {
-	int lock_failed;
-	unsigned long flags;
-
-	/*
-	 * Here and in __up_console_sem() we need to be in safe mode,
-	 * because spindump/WARN/etc from under console ->lock will
-	 * deadlock in printk()->down_trylock_console_sem() otherwise.
-	 */
-	printk_safe_enter_irqsave(flags);
-	lock_failed = down_trylock(&console_sem);
-	printk_safe_exit_irqrestore(flags);
-
-	if (lock_failed)
+	if (down_trylock(&console_sem))
 		return 1;
 	mutex_acquire(&console_lock_dep_map, 0, 1, ip);
 	return 0;
@@ -245,13 +236,9 @@ static int __down_trylock_console_sem(unsigned long ip)
 
 static void __up_console_sem(unsigned long ip)
 {
-	unsigned long flags;
-
 	mutex_release(&console_lock_dep_map, ip);
 
-	printk_safe_enter_irqsave(flags);
 	up(&console_sem);
-	printk_safe_exit_irqrestore(flags);
 }
 #define up_console_sem() __up_console_sem(_RET_IP_)
 
@@ -265,11 +252,6 @@ static void __up_console_sem(unsigned long ip)
  */
 static int console_locked, console_suspended;
 
-/*
- * If exclusive_console is non-NULL then only this console is to be printed to.
- */
-static struct console *exclusive_console;
-
 /*
  *	Array of consoles built from command line options (console=)
  */
@@ -367,6 +349,7 @@ enum log_flags {
 
 struct printk_log {
 	u64 ts_nsec;		/* timestamp in nanoseconds */
+	u16 cpu;		/* cpu that generated record */
 	u16 len;		/* length of entire record */
 	u16 text_len;		/* length of text buffer */
 	u16 dict_len;		/* length of dictionary buffer */
@@ -382,65 +365,22 @@ __packed __aligned(4)
 #endif
 ;
 
-/*
- * The logbuf_lock protects kmsg buffer, indices, counters.  This can be taken
- * within the scheduler's rq lock. It must be released before calling
- * console_unlock() or anything else that might wake up a process.
- */
-DEFINE_RAW_SPINLOCK(logbuf_lock);
-
-/*
- * Helper macros to lock/unlock logbuf_lock and switch between
- * printk-safe/unsafe modes.
- */
-#define logbuf_lock_irq()				\
-	do {						\
-		printk_safe_enter_irq();		\
-		raw_spin_lock(&logbuf_lock);		\
-	} while (0)
-
-#define logbuf_unlock_irq()				\
-	do {						\
-		raw_spin_unlock(&logbuf_lock);		\
-		printk_safe_exit_irq();			\
-	} while (0)
-
-#define logbuf_lock_irqsave(flags)			\
-	do {						\
-		printk_safe_enter_irqsave(flags);	\
-		raw_spin_lock(&logbuf_lock);		\
-	} while (0)
-
-#define logbuf_unlock_irqrestore(flags)		\
-	do {						\
-		raw_spin_unlock(&logbuf_lock);		\
-		printk_safe_exit_irqrestore(flags);	\
-	} while (0)
+DECLARE_STATIC_PRINTKRB_CPULOCK(printk_cpulock);
 
 #ifdef CONFIG_PRINTK
-DECLARE_WAIT_QUEUE_HEAD(log_wait);
-/* the next printk record to read by syslog(READ) or /proc/kmsg */
+/* record buffer */
+DECLARE_STATIC_PRINTKRB(printk_rb, CONFIG_LOG_BUF_SHIFT, &printk_cpulock);
+
+static DEFINE_MUTEX(syslog_lock);
+DECLARE_STATIC_PRINTKRB_ITER(syslog_iter, &printk_rb);
+
+/* the last printk record to read by syslog(READ) or /proc/kmsg */
 static u64 syslog_seq;
-static u32 syslog_idx;
 static size_t syslog_partial;
 static bool syslog_time;
 
-/* index and sequence number of the first record stored in the buffer */
-static u64 log_first_seq;
-static u32 log_first_idx;
-
-/* index and sequence number of the next record to store in the buffer */
-static u64 log_next_seq;
-static u32 log_next_idx;
-
-/* the next printk record to write to the console */
-static u64 console_seq;
-static u32 console_idx;
-static u64 exclusive_console_stop_seq;
-
 /* the next printk record to read after the last 'clear' command */
 static u64 clear_seq;
-static u32 clear_idx;
 
 #ifdef CONFIG_PRINTK_CALLER
 #define PREFIX_MAX		48
@@ -452,36 +392,16 @@ static u32 clear_idx;
 #define LOG_LEVEL(v)		((v) & 0x07)
 #define LOG_FACILITY(v)		((v) >> 3 & 0xff)
 
-/* record buffer */
-#define LOG_ALIGN __alignof__(struct printk_log)
-#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
-#define LOG_BUF_LEN_MAX (u32)(1 << 31)
-static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
-static char *log_buf = __log_buf;
-static u32 log_buf_len = __LOG_BUF_LEN;
-
-/*
- * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before
- * per_cpu_areas are initialised. This variable is set to true when
- * it's safe to access per-CPU data.
- */
-static bool __printk_percpu_data_ready __read_mostly;
-
-bool printk_percpu_data_ready(void)
-{
-	return __printk_percpu_data_ready;
-}
-
 /* Return log buffer address */
 char *log_buf_addr_get(void)
 {
-	return log_buf;
+	return printk_rb.buffer;
 }
 
 /* Return log buffer size */
 u32 log_buf_len_get(void)
 {
-	return log_buf_len;
+	return (1 << printk_rb.size_bits);
 }
 
 /* human readable text of the record */
@@ -496,180 +416,50 @@ static char *log_dict(const struct printk_log *msg)
 	return (char *)msg + sizeof(struct printk_log) + msg->text_len;
 }
 
-/* get record by index; idx must point to valid msg */
-static struct printk_log *log_from_idx(u32 idx)
-{
-	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
-	/*
-	 * A length == 0 record is the end of buffer marker. Wrap around and
-	 * read the message at the start of the buffer.
-	 */
-	if (!msg->len)
-		return (struct printk_log *)log_buf;
-	return msg;
-}
-
-/* get next record; idx must point to valid msg */
-static u32 log_next(u32 idx)
-{
-	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
-	/* length == 0 indicates the end of the buffer; wrap */
-	/*
-	 * A length == 0 record is the end of buffer marker. Wrap around and
-	 * read the message at the start of the buffer as *this* one, and
-	 * return the one after that.
-	 */
-	if (!msg->len) {
-		msg = (struct printk_log *)log_buf;
-		return msg->len;
-	}
-	return idx + msg->len;
-}
-
-/*
- * Check whether there is enough free space for the given message.
- *
- * The same values of first_idx and next_idx mean that the buffer
- * is either empty or full.
- *
- * If the buffer is empty, we must respect the position of the indexes.
- * They cannot be reset to the beginning of the buffer.
- */
-static int logbuf_has_space(u32 msg_size, bool empty)
-{
-	u32 free;
-
-	if (log_next_idx > log_first_idx || empty)
-		free = max(log_buf_len - log_next_idx, log_first_idx);
-	else
-		free = log_first_idx - log_next_idx;
-
-	/*
-	 * We need space also for an empty header that signalizes wrapping
-	 * of the buffer.
-	 */
-	return free >= msg_size + sizeof(struct printk_log);
-}
-
-static int log_make_free_space(u32 msg_size)
-{
-	while (log_first_seq < log_next_seq &&
-	       !logbuf_has_space(msg_size, false)) {
-		/* drop old messages until we have enough contiguous space */
-		log_first_idx = log_next(log_first_idx);
-		log_first_seq++;
-	}
-
-	if (clear_seq < log_first_seq) {
-		clear_seq = log_first_seq;
-		clear_idx = log_first_idx;
-	}
-
-	/* sequence numbers are equal, so the log buffer is empty */
-	if (logbuf_has_space(msg_size, log_first_seq == log_next_seq))
-		return 0;
-
-	return -ENOMEM;
-}
-
-/* compute the message size including the padding bytes */
-static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len)
-{
-	u32 size;
-
-	size = sizeof(struct printk_log) + text_len + dict_len;
-	*pad_len = (-size) & (LOG_ALIGN - 1);
-	size += *pad_len;
-
-	return size;
-}
-
-/*
- * Define how much of the log buffer we could take at maximum. The value
- * must be greater than two. Note that only half of the buffer is available
- * when the index points to the middle.
- */
-#define MAX_LOG_TAKE_PART 4
-static const char trunc_msg[] = "<truncated>";
-
-static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
-			u16 *dict_len, u32 *pad_len)
-{
-	/*
-	 * The message should not take the whole buffer. Otherwise, it might
-	 * get removed too soon.
-	 */
-	u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART;
-	if (*text_len > max_text_len)
-		*text_len = max_text_len;
-	/* enable the warning message */
-	*trunc_msg_len = strlen(trunc_msg);
-	/* disable the "dict" completely */
-	*dict_len = 0;
-	/* compute the size again, count also the warning message */
-	return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
-}
+static void printk_emergency(char *buffer, int level, u64 ts_nsec, u16 cpu,
+			     char *text, u16 text_len);
 
 /* insert record into the buffer, discard old ones, update heads */
 static int log_store(u32 caller_id, int facility, int level,
-		     enum log_flags flags, u64 ts_nsec,
+		     enum log_flags flags, u64 ts_nsec, u16 cpu,
 		     const char *dict, u16 dict_len,
 		     const char *text, u16 text_len)
 {
 	struct printk_log *msg;
-	u32 size, pad_len;
-	u16 trunc_msg_len = 0;
+	struct prb_handle h;
+	char *rbuf;
+	u32 size;
 
-	/* number of '\0' padding bytes to next message */
-	size = msg_used_size(text_len, dict_len, &pad_len);
+	size = sizeof(*msg) + text_len + dict_len;
 
-	if (log_make_free_space(size)) {
-		/* truncate the message if it is too long for empty buffer */
-		size = truncate_msg(&text_len, &trunc_msg_len,
-				    &dict_len, &pad_len);
-		/* survive when the log buffer is too small for trunc_msg */
-		if (log_make_free_space(size))
-			return 0;
-	}
-
-	if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) {
+	rbuf = prb_reserve(&h, &printk_rb, size);
+	if (!rbuf) {
 		/*
-		 * This message + an additional empty header does not fit
-		 * at the end of the buffer. Add an empty header with len == 0
-		 * to signify a wrap around.
+		 * An emergency message would have been printed, but
+		 * it cannot be stored in the log.
 		 */
-		memset(log_buf + log_next_idx, 0, sizeof(struct printk_log));
-		log_next_idx = 0;
+		prb_inc_lost(&printk_rb);
+		return 0;
 	}
 
 	/* fill message */
-	msg = (struct printk_log *)(log_buf + log_next_idx);
+	msg = (struct printk_log *)rbuf;
 	memcpy(log_text(msg), text, text_len);
 	msg->text_len = text_len;
-	if (trunc_msg_len) {
-		memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len);
-		msg->text_len += trunc_msg_len;
-	}
 	memcpy(log_dict(msg), dict, dict_len);
 	msg->dict_len = dict_len;
 	msg->facility = facility;
 	msg->level = level & 7;
 	msg->flags = flags & 0x1f;
-	if (ts_nsec > 0)
-		msg->ts_nsec = ts_nsec;
-	else
-		msg->ts_nsec = local_clock();
+	msg->ts_nsec = ts_nsec;
 #ifdef CONFIG_PRINTK_CALLER
 	msg->caller_id = caller_id;
 #endif
-	memset(log_dict(msg) + dict_len, 0, pad_len);
+	msg->cpu = cpu;
 	msg->len = size;
 
 	/* insert message */
-	log_next_idx += msg->len;
-	log_next_seq++;
+	prb_commit(&h);
 
 	return msg->text_len;
 }
@@ -739,9 +529,9 @@ static ssize_t msg_print_ext_header(char *buf, size_t size,
 
 	do_div(ts_usec, 1000);
 
-	return scnprintf(buf, size, "%u,%llu,%llu,%c%s;",
+	return scnprintf(buf, size, "%u,%llu,%llu,%c%s,%hu;",
 			 (msg->facility << 3) | msg->level, seq, ts_usec,
-			 msg->flags & LOG_CONT ? 'c' : '-', caller);
+			 msg->flags & LOG_CONT ? 'c' : '-', caller, msg->cpu);
 }
 
 static ssize_t msg_print_ext_body(char *buf, size_t size,
@@ -792,13 +582,18 @@ static ssize_t msg_print_ext_body(char *buf, size_t size,
 	return p - buf;
 }
 
+#define PRINTK_SPRINT_MAX (LOG_LINE_MAX + PREFIX_MAX)
+#define PRINTK_RECORD_MAX (sizeof(struct printk_log) + \
+				CONSOLE_EXT_LOG_MAX + PRINTK_SPRINT_MAX)
+
 /* /dev/kmsg - userspace message inject/listen interface */
 struct devkmsg_user {
 	u64 seq;
-	u32 idx;
+	struct prb_iterator iter;
 	struct ratelimit_state rs;
 	struct mutex lock;
 	char buf[CONSOLE_EXT_LOG_MAX];
+	char msgbuf[PRINTK_RECORD_MAX];
 };
 
 static __printf(3, 4) __cold
@@ -881,9 +676,11 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 			    size_t count, loff_t *ppos)
 {
 	struct devkmsg_user *user = file->private_data;
+	struct prb_iterator backup_iter;
 	struct printk_log *msg;
-	size_t len;
 	ssize_t ret;
+	size_t len;
+	u64 seq;
 
 	if (!user)
 		return -EBADF;
@@ -892,52 +689,63 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 	if (ret)
 		return ret;
 
-	logbuf_lock_irq();
-	while (user->seq == log_next_seq) {
-		if (file->f_flags & O_NONBLOCK) {
-			ret = -EAGAIN;
-			logbuf_unlock_irq();
-			goto out;
-		}
+	/* make a backup copy in case there is a problem */
+	prb_iter_copy(&backup_iter, &user->iter);
 
-		logbuf_unlock_irq();
-		ret = wait_event_interruptible(log_wait,
-					       user->seq != log_next_seq);
-		if (ret)
-			goto out;
-		logbuf_lock_irq();
+	if (file->f_flags & O_NONBLOCK) {
+		ret = prb_iter_next(&user->iter, &user->msgbuf[0],
+				      sizeof(user->msgbuf), &seq);
+	} else {
+		ret = prb_iter_wait_next(&user->iter, &user->msgbuf[0],
+					   sizeof(user->msgbuf), &seq);
 	}
-
-	if (user->seq < log_first_seq) {
-		/* our last seen message is gone, return error and reset */
-		user->idx = log_first_idx;
-		user->seq = log_first_seq;
+	if (ret == 0) {
+		/* end of list */
+		ret = -EAGAIN;
+		goto out;
+	} else if (ret == -EINVAL) {
+		/* iterator invalid, return error and reset */
 		ret = -EPIPE;
-		logbuf_unlock_irq();
+		prb_iter_init(&user->iter, &printk_rb, &user->seq);
+		goto out;
+	} else if (ret < 0) {
+		/* interrupted by signal */
 		goto out;
 	}
 
-	msg = log_from_idx(user->idx);
+	user->seq++;
+	if (user->seq < seq) {
+		ret = -EPIPE;
+		goto restore_out;
+	}
+
+	msg = (struct printk_log *)&user->msgbuf[0];
 	len = msg_print_ext_header(user->buf, sizeof(user->buf),
 				   msg, user->seq);
 	len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len,
 				  log_dict(msg), msg->dict_len,
 				  log_text(msg), msg->text_len);
 
-	user->idx = log_next(user->idx);
-	user->seq++;
-	logbuf_unlock_irq();
-
 	if (len > count) {
 		ret = -EINVAL;
-		goto out;
+		goto restore_out;
 	}
 
 	if (copy_to_user(buf, user->buf, len)) {
 		ret = -EFAULT;
-		goto out;
+		goto restore_out;
 	}
+
 	ret = len;
+	goto out;
+restore_out:
+	/*
+	 * There was an error, but this message should not be
+	 * lost because of it. Restore the backup and setup
+	 * seq so that it will work with the next read.
+	 */
+	prb_iter_copy(&user->iter, &backup_iter);
+	user->seq = seq - 1;
 out:
 	mutex_unlock(&user->lock);
 	return ret;
@@ -954,19 +762,22 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct devkmsg_user *user = file->private_data;
-	loff_t ret = 0;
+	loff_t ret;
+	u64 seq;
 
 	if (!user)
 		return -EBADF;
 	if (offset)
 		return -ESPIPE;
 
-	logbuf_lock_irq();
+	ret = mutex_lock_interruptible(&user->lock);
+	if (ret)
+		return ret;
+
 	switch (whence) {
 	case SEEK_SET:
 		/* the first record */
-		user->idx = log_first_idx;
-		user->seq = log_first_seq;
+		prb_iter_init(&user->iter, &printk_rb, &user->seq);
 		break;
 	case SEEK_DATA:
 		/*
@@ -974,40 +785,87 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
 		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
 		 * changes no global state, and does not clear anything.
 		 */
-		user->idx = clear_idx;
-		user->seq = clear_seq;
+		for (;;) {
+			prb_iter_init(&user->iter, &printk_rb, &seq);
+			ret = prb_iter_seek(&user->iter, clear_seq);
+			if (ret > 0) {
+				/* seeked to clear seq */
+				user->seq = clear_seq;
+				break;
+			} else if (ret == 0) {
+				/*
+				 * The end of the list was hit without
+				 * ever seeing the clear seq. Just
+				 * seek to the beginning of the list.
+				 */
+				prb_iter_init(&user->iter, &printk_rb,
+					      &user->seq);
+				break;
+			}
+			/* iterator invalid, start over */
+
+			/* reset clear_seq if it is no longer available */
+			if (seq > clear_seq)
+				clear_seq = 0;
+		}
+		ret = 0;
 		break;
 	case SEEK_END:
 		/* after the last record */
-		user->idx = log_next_idx;
-		user->seq = log_next_seq;
+		for (;;) {
+			ret = prb_iter_next(&user->iter, NULL, 0, &user->seq);
+			if (ret == 0)
+				break;
+			else if (ret > 0)
+				continue;
+			/* iterator invalid, start over */
+			prb_iter_init(&user->iter, &printk_rb, &user->seq);
+		}
+		ret = 0;
 		break;
 	default:
 		ret = -EINVAL;
 	}
-	logbuf_unlock_irq();
+
+	mutex_unlock(&user->lock);
 	return ret;
 }
 
+struct wait_queue_head *printk_wait_queue(void)
+{
+	/* FIXME: using prb internals! */
+	return printk_rb.wq;
+}
+
 static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
 {
 	struct devkmsg_user *user = file->private_data;
+	struct prb_iterator iter;
 	__poll_t ret = 0;
+	int rbret;
+	u64 seq;
 
 	if (!user)
 		return EPOLLERR|EPOLLNVAL;
 
-	poll_wait(file, &log_wait, wait);
+	poll_wait(file, printk_wait_queue(), wait);
 
-	logbuf_lock_irq();
-	if (user->seq < log_next_seq) {
-		/* return error when data has vanished underneath us */
-		if (user->seq < log_first_seq)
-			ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
-		else
-			ret = EPOLLIN|EPOLLRDNORM;
-	}
-	logbuf_unlock_irq();
+	mutex_lock(&user->lock);
+
+	/* use copy so no actual iteration takes place */
+	prb_iter_copy(&iter, &user->iter);
+
+	rbret = prb_iter_next(&iter, &user->msgbuf[0],
+			      sizeof(user->msgbuf), &seq);
+	if (rbret == 0)
+		goto out;
+
+	ret = EPOLLIN|EPOLLRDNORM;
+
+	if (rbret < 0 || (seq - user->seq) != 1)
+		ret |= EPOLLERR|EPOLLPRI;
+out:
+	mutex_unlock(&user->lock);
 
 	return ret;
 }
@@ -1037,10 +895,7 @@ static int devkmsg_open(struct inode *inode, struct file *file)
 
 	mutex_init(&user->lock);
 
-	logbuf_lock_irq();
-	user->idx = log_first_idx;
-	user->seq = log_first_seq;
-	logbuf_unlock_irq();
+	prb_iter_init(&user->iter, &printk_rb, &user->seq);
 
 	file->private_data = user;
 	return 0;
@@ -1080,11 +935,6 @@ const struct file_operations kmsg_fops = {
  */
 void log_buf_vmcoreinfo_setup(void)
 {
-	VMCOREINFO_SYMBOL(log_buf);
-	VMCOREINFO_SYMBOL(log_buf_len);
-	VMCOREINFO_SYMBOL(log_first_idx);
-	VMCOREINFO_SYMBOL(clear_idx);
-	VMCOREINFO_SYMBOL(log_next_idx);
 	/*
 	 * Export struct printk_log size and field offsets. User space tools can
 	 * parse it and detect any changes to structure down the line.
@@ -1100,6 +950,8 @@ void log_buf_vmcoreinfo_setup(void)
 }
 #endif
 
+/* FIXME: no support for buffer resizing */
+#if 0
 /* requested log_buf_len from kernel cmdline */
 static unsigned long __initdata new_log_buf_len;
 
@@ -1165,29 +1017,16 @@ static void __init log_buf_add_cpu(void)
 #else /* !CONFIG_SMP */
 static inline void log_buf_add_cpu(void) {}
 #endif /* CONFIG_SMP */
-
-static void __init set_percpu_data_ready(void)
-{
-	printk_safe_init();
-	/* Make sure we set this flag only after printk_safe() init is done */
-	barrier();
-	__printk_percpu_data_ready = true;
-}
+#endif /* 0 */
 
 void __init setup_log_buf(int early)
 {
+/* FIXME: no support for buffer resizing */
+#if 0
 	unsigned long flags;
 	char *new_log_buf;
 	unsigned int free;
 
-	/*
-	 * Some archs call setup_log_buf() multiple times - first is very
-	 * early, e.g. from setup_arch(), and second - when percpu_areas
-	 * are initialised.
-	 */
-	if (!early)
-		set_percpu_data_ready();
-
 	if (log_buf != __log_buf)
 		return;
 
@@ -1215,6 +1054,7 @@ void __init setup_log_buf(int early)
 	pr_info("log_buf_len: %u bytes\n", log_buf_len);
 	pr_info("early log buf free: %u(%u%%)\n",
 		free, (free * 100) / __LOG_BUF_LEN);
+#endif
 }
 
 static bool __read_mostly ignore_loglevel;
@@ -1295,6 +1135,11 @@ static inline void boot_delay_msec(int level)
 static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 
+static size_t print_cpu(u16 cpu, char *buf)
+{
+	return sprintf(buf, "%03hu: ", cpu);
+}
+
 static size_t print_syslog(unsigned int level, char *buf)
 {
 	return sprintf(buf, "<%u>", level);
@@ -1338,6 +1183,7 @@ static size_t print_prefix(const struct printk_log *msg, bool syslog,
 		buf[len++] = ' ';
 		buf[len] = '\0';
 	}
+	len += print_cpu(msg->cpu, buf + len);
 
 	return len;
 }
@@ -1383,31 +1229,43 @@ static size_t msg_print_text(const struct printk_log *msg, bool syslog,
 	return len;
 }
 
-static int syslog_print(char __user *buf, int size)
+static int syslog_print(char __user *buf, int size, char *text,
+			char *msgbuf, int *locked)
 {
-	char *text;
+	struct prb_iterator iter;
 	struct printk_log *msg;
 	int len = 0;
-
-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
-	if (!text)
-		return -ENOMEM;
+	u64 seq;
+	int ret;
 
 	while (size > 0) {
 		size_t n;
 		size_t skip;
 
-		logbuf_lock_irq();
-		if (syslog_seq < log_first_seq) {
-			/* messages are gone, move to first one */
-			syslog_seq = log_first_seq;
-			syslog_idx = log_first_idx;
-			syslog_partial = 0;
-		}
-		if (syslog_seq == log_next_seq) {
-			logbuf_unlock_irq();
+		for (;;) {
+			prb_iter_copy(&iter, &syslog_iter);
+			ret = prb_iter_next(&iter, msgbuf,
+					    PRINTK_RECORD_MAX, &seq);
+			if (ret < 0) {
+				/* messages are gone, move to first one */
+				prb_iter_init(&syslog_iter, &printk_rb,
+					      &syslog_seq);
+				syslog_partial = 0;
+				continue;
+			}
 			break;
 		}
+		if (ret == 0)
+			break;
+
+		/*
+		 * If messages have been missed, the partial tracker
+		 * is no longer valid and must be reset.
+		 */
+		if (syslog_seq > 0 && seq - 1 != syslog_seq) {
+			syslog_seq = seq - 1;
+			syslog_partial = 0;
+		}
 
 		/*
 		 * To keep reading/counting partial line consistent,
@@ -1416,131 +1274,213 @@ static int syslog_print(char __user *buf, int size)
 		if (!syslog_partial)
 			syslog_time = printk_time;
 
+		msg = (struct printk_log *)msgbuf;
+
 		skip = syslog_partial;
-		msg = log_from_idx(syslog_idx);
 		n = msg_print_text(msg, true, syslog_time, text,
-				   LOG_LINE_MAX + PREFIX_MAX);
+				   PRINTK_SPRINT_MAX);
 		if (n - syslog_partial <= size) {
 			/* message fits into buffer, move forward */
-			syslog_idx = log_next(syslog_idx);
-			syslog_seq++;
+			prb_iter_next(&syslog_iter, NULL, 0, &syslog_seq);
 			n -= syslog_partial;
 			syslog_partial = 0;
-		} else if (!len){
+		} else if (!len) {
 			/* partial read(), remember position */
 			n = size;
 			syslog_partial += n;
 		} else
 			n = 0;
-		logbuf_unlock_irq();
 
 		if (!n)
 			break;
 
+		mutex_unlock(&syslog_lock);
 		if (copy_to_user(buf, text + skip, n)) {
 			if (!len)
 				len = -EFAULT;
+			*locked = 0;
 			break;
 		}
+		ret = mutex_lock_interruptible(&syslog_lock);
 
 		len += n;
 		size -= n;
 		buf += n;
-	}
 
-	kfree(text);
-	return len;
-}
-
-static int syslog_print_all(char __user *buf, int size, bool clear)
-{
-	char *text;
-	int len = 0;
-	u64 next_seq;
-	u64 seq;
-	u32 idx;
-	bool time;
-
-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
-	if (!text)
-		return -ENOMEM;
-
-	time = printk_time;
-	logbuf_lock_irq();
-	/*
-	 * Find first record that fits, including all following records,
-	 * into the user-provided buffer for this dump.
-	 */
-	seq = clear_seq;
-	idx = clear_idx;
-	while (seq < log_next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		len += msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	/* move first record forward until length fits into the buffer */
-	seq = clear_seq;
-	idx = clear_idx;
-	while (len > size && seq < log_next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		len -= msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	/* last message fitting into this dump */
-	next_seq = log_next_seq;
-
-	len = 0;
-	while (len >= 0 && seq < next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-		int textlen = msg_print_text(msg, true, time, text,
-					     LOG_LINE_MAX + PREFIX_MAX);
-
-		idx = log_next(idx);
-		seq++;
-
-		logbuf_unlock_irq();
-		if (copy_to_user(buf + len, text, textlen))
-			len = -EFAULT;
-		else
-			len += textlen;
-		logbuf_lock_irq();
-
-		if (seq < log_first_seq) {
-			/* messages are gone, move to next one */
-			seq = log_first_seq;
-			idx = log_first_idx;
+		if (ret) {
+			if (!len)
+				len = ret;
+			*locked = 0;
+			break;
 		}
 	}
 
-	if (clear) {
-		clear_seq = log_next_seq;
-		clear_idx = log_next_idx;
-	}
-	logbuf_unlock_irq();
+	return len;
+}
+
+static int count_remaining(struct prb_iterator *iter, u64 until_seq,
+			   char *msgbuf, int size, bool records, bool time)
+{
+	struct prb_iterator local_iter;
+	struct printk_log *msg;
+	int len = 0;
+	u64 seq;
+	int ret;
+
+	prb_iter_copy(&local_iter, iter);
+	for (;;) {
+		ret = prb_iter_next(&local_iter, msgbuf, size, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/* the iter is invalid, restart from head */
+			prb_iter_init(&local_iter, &printk_rb, NULL);
+			len = 0;
+			continue;
+		}
+
+		if (until_seq && seq >= until_seq)
+			break;
+
+		if (records) {
+			len++;
+		} else {
+			msg = (struct printk_log *)msgbuf;
+			len += msg_print_text(msg, true, time, NULL, 0);
+		}
+	}
 
-	kfree(text);
 	return len;
 }
 
 static void syslog_clear(void)
 {
-	logbuf_lock_irq();
-	clear_seq = log_next_seq;
-	clear_idx = log_next_idx;
-	logbuf_unlock_irq();
+	struct prb_iterator iter;
+	int ret;
+
+	prb_iter_init(&iter, &printk_rb, &clear_seq);
+	for (;;) {
+		ret = prb_iter_next(&iter, NULL, 0, &clear_seq);
+		if (ret == 0)
+			break;
+		else if (ret < 0)
+			prb_iter_init(&iter, &printk_rb, &clear_seq);
+	}
+}
+
+static int syslog_print_all(char __user *buf, int size, bool clear)
+{
+	struct prb_iterator iter;
+	struct printk_log *msg;
+	char *msgbuf = NULL;
+	char *text = NULL;
+	int textlen;
+	u64 seq = 0;
+	int len = 0;
+	bool time;
+	int ret;
+
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+	if (!text)
+		return -ENOMEM;
+	msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!msgbuf) {
+		kfree(text);
+		return -ENOMEM;
+	}
+
+	time = printk_time;
+
+	/*
+	 * Setup iter to last event before clear. Clear may
+	 * be lost, but keep going with a best effort.
+	 */
+	prb_iter_init(&iter, &printk_rb, NULL);
+	prb_iter_seek(&iter, clear_seq);
+
+	/* count the total bytes after clear */
+	len = count_remaining(&iter, 0, msgbuf, PRINTK_RECORD_MAX,
+			      false, time);
+
+	/* move iter forward until length fits into the buffer */
+	while (len > size) {
+		ret = prb_iter_next(&iter, msgbuf,
+				    PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * The iter is now invalid so clear will
+			 * also be invalid. Restart from the head.
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			len = count_remaining(&iter, 0, msgbuf,
+					      PRINTK_RECORD_MAX, false, time);
+			continue;
+		}
+
+		msg = (struct printk_log *)msgbuf;
+		len -= msg_print_text(msg, true, time, NULL, 0);
+
+		if (clear)
+			clear_seq = seq;
+	}
+
+	/* copy messages to buffer */
+	len = 0;
+	while (len >= 0 && len < size) {
+		if (clear)
+			clear_seq = seq;
+
+		ret = prb_iter_next(&iter, msgbuf,
+				    PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * The iter is now invalid. Make a best
+			 * effort to grab the rest of the log
+			 * from the new head.
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		msg = (struct printk_log *)msgbuf;
+		textlen = msg_print_text(msg, true, time, text,
+					 PRINTK_SPRINT_MAX);
+		if (textlen < 0) {
+			len = textlen;
+			break;
+		}
+
+		if (len + textlen > size)
+			break;
+
+		if (copy_to_user(buf + len, text, textlen))
+			len = -EFAULT;
+		else
+			len += textlen;
+	}
+
+	if (clear && !seq)
+		syslog_clear();
+
+	kfree(text);
+	kfree(msgbuf);
+	return len;
 }
 
 int do_syslog(int type, char __user *buf, int len, int source)
 {
 	bool clear = false;
 	static int saved_console_loglevel = LOGLEVEL_DEFAULT;
+	struct prb_iterator iter;
+	char *msgbuf = NULL;
+	char *text = NULL;
+	int locked;
 	int error;
+	int ret;
 
 	error = check_syslog_permissions(type, source);
 	if (error)
@@ -1558,11 +1498,49 @@ int do_syslog(int type, char __user *buf, int len, int source)
 			return 0;
 		if (!access_ok(buf, len))
 			return -EFAULT;
-		error = wait_event_interruptible(log_wait,
-						 syslog_seq != log_next_seq);
+
+		text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+		msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+		if (!text || !msgbuf) {
+			error = -ENOMEM;
+			goto out;
+		}
+
+		error = mutex_lock_interruptible(&syslog_lock);
 		if (error)
-			return error;
-		error = syslog_print(buf, len);
+			goto out;
+
+		/*
+		 * Wait until a first message is available. Use a copy
+		 * because no iteration should occur for syslog now.
+		 */
+		for (;;) {
+			prb_iter_copy(&iter, &syslog_iter);
+
+			mutex_unlock(&syslog_lock);
+			ret = prb_iter_wait_next(&iter, NULL, 0, NULL);
+			if (ret == -ERESTARTSYS) {
+				error = ret;
+				goto out;
+			}
+			error = mutex_lock_interruptible(&syslog_lock);
+			if (error)
+				goto out;
+
+			if (ret == -EINVAL) {
+				prb_iter_init(&syslog_iter, &printk_rb,
+					      &syslog_seq);
+				syslog_partial = 0;
+				continue;
+			}
+			break;
+		}
+
+		/* print as much as will fit in the user buffer */
+		locked = 1;
+		error = syslog_print(buf, len, text, msgbuf, &locked);
+		if (locked)
+			mutex_unlock(&syslog_lock);
 		break;
 	/* Read/clear last kernel messages */
 	case SYSLOG_ACTION_READ_CLEAR:
@@ -1607,47 +1585,43 @@ int do_syslog(int type, char __user *buf, int len, int source)
 		break;
 	/* Number of chars in the log buffer */
 	case SYSLOG_ACTION_SIZE_UNREAD:
-		logbuf_lock_irq();
-		if (syslog_seq < log_first_seq) {
-			/* messages are gone, move to first one */
-			syslog_seq = log_first_seq;
-			syslog_idx = log_first_idx;
-			syslog_partial = 0;
-		}
+		msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+		if (!msgbuf)
+			return -ENOMEM;
+
+		error = mutex_lock_interruptible(&syslog_lock);
+		if (error)
+			goto out;
+
 		if (source == SYSLOG_FROM_PROC) {
 			/*
 			 * Short-cut for poll(/"proc/kmsg") which simply checks
 			 * for pending data, not the size; return the count of
 			 * records, not the length.
 			 */
-			error = log_next_seq - syslog_seq;
+			error = count_remaining(&syslog_iter, 0, msgbuf,
+						PRINTK_RECORD_MAX, true,
+						printk_time);
 		} else {
-			u64 seq = syslog_seq;
-			u32 idx = syslog_idx;
-			bool time = syslog_partial ? syslog_time : printk_time;
-
-			while (seq < log_next_seq) {
-				struct printk_log *msg = log_from_idx(idx);
-
-				error += msg_print_text(msg, true, time, NULL,
-							0);
-				time = printk_time;
-				idx = log_next(idx);
-				seq++;
-			}
+			error = count_remaining(&syslog_iter, 0, msgbuf,
+						PRINTK_RECORD_MAX, false,
+						printk_time);
 			error -= syslog_partial;
 		}
-		logbuf_unlock_irq();
+
+		mutex_unlock(&syslog_lock);
 		break;
 	/* Size of the log buffer */
 	case SYSLOG_ACTION_SIZE_BUFFER:
-		error = log_buf_len;
+		error = prb_buffer_size(&printk_rb);
 		break;
 	default:
 		error = -EINVAL;
 		break;
 	}
-
+out:
+	kfree(msgbuf);
+	kfree(text);
 	return error;
 }
 
@@ -1656,179 +1630,11 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
 	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
 }
 
-/*
- * Special console_lock variants that help to reduce the risk of soft-lockups.
- * They allow to pass console_lock to another printk() call using a busy wait.
- */
-
-#ifdef CONFIG_LOCKDEP
-static struct lockdep_map console_owner_dep_map = {
-	.name = "console_owner"
-};
-#endif
-
-static DEFINE_RAW_SPINLOCK(console_owner_lock);
-static struct task_struct *console_owner;
-static bool console_waiter;
-
-/**
- * console_lock_spinning_enable - mark beginning of code where another
- *	thread might safely busy wait
- *
- * This basically converts console_lock into a spinlock. This marks
- * the section where the console_lock owner can not sleep, because
- * there may be a waiter spinning (like a spinlock). Also it must be
- * ready to hand over the lock at the end of the section.
- */
-static void console_lock_spinning_enable(void)
-{
-	raw_spin_lock(&console_owner_lock);
-	console_owner = current;
-	raw_spin_unlock(&console_owner_lock);
-
-	/* The waiter may spin on us after setting console_owner */
-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
-}
-
-/**
- * console_lock_spinning_disable_and_check - mark end of code where another
- *	thread was able to busy wait and check if there is a waiter
- *
- * This is called at the end of the section where spinning is allowed.
- * It has two functions. First, it is a signal that it is no longer
- * safe to start busy waiting for the lock. Second, it checks if
- * there is a busy waiter and passes the lock rights to her.
- *
- * Important: Callers lose the lock if there was a busy waiter.
- *	They must not touch items synchronized by console_lock
- *	in this case.
- *
- * Return: 1 if the lock rights were passed, 0 otherwise.
- */
-static int console_lock_spinning_disable_and_check(void)
-{
-	int waiter;
-
-	raw_spin_lock(&console_owner_lock);
-	waiter = READ_ONCE(console_waiter);
-	console_owner = NULL;
-	raw_spin_unlock(&console_owner_lock);
-
-	if (!waiter) {
-		spin_release(&console_owner_dep_map, _THIS_IP_);
-		return 0;
-	}
-
-	/* The waiter is now free to continue */
-	WRITE_ONCE(console_waiter, false);
-
-	spin_release(&console_owner_dep_map, _THIS_IP_);
-
-	/*
-	 * Hand off console_lock to waiter. The waiter will perform
-	 * the up(). After this, the waiter is the console_lock owner.
-	 */
-	mutex_release(&console_lock_dep_map, _THIS_IP_);
-	return 1;
-}
-
-/**
- * console_trylock_spinning - try to get console_lock by busy waiting
- *
- * This allows to busy wait for the console_lock when the current
- * owner is running in specially marked sections. It means that
- * the current owner is running and cannot reschedule until it
- * is ready to lose the lock.
- *
- * Return: 1 if we got the lock, 0 othrewise
- */
-static int console_trylock_spinning(void)
-{
-	struct task_struct *owner = NULL;
-	bool waiter;
-	bool spin = false;
-	unsigned long flags;
-
-	if (console_trylock())
-		return 1;
-
-	printk_safe_enter_irqsave(flags);
-
-	raw_spin_lock(&console_owner_lock);
-	owner = READ_ONCE(console_owner);
-	waiter = READ_ONCE(console_waiter);
-	if (!waiter && owner && owner != current) {
-		WRITE_ONCE(console_waiter, true);
-		spin = true;
-	}
-	raw_spin_unlock(&console_owner_lock);
-
-	/*
-	 * If there is an active printk() writing to the
-	 * consoles, instead of having it write our data too,
-	 * see if we can offload that load from the active
-	 * printer, and do some printing ourselves.
-	 * Go into a spin only if there isn't already a waiter
-	 * spinning, and there is an active printer, and
-	 * that active printer isn't us (recursive printk?).
-	 */
-	if (!spin) {
-		printk_safe_exit_irqrestore(flags);
-		return 0;
-	}
-
-	/* We spin waiting for the owner to release us */
-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
-	/* Owner will clear console_waiter on hand off */
-	while (READ_ONCE(console_waiter))
-		cpu_relax();
-	spin_release(&console_owner_dep_map, _THIS_IP_);
-
-	printk_safe_exit_irqrestore(flags);
-	/*
-	 * The owner passed the console lock to us.
-	 * Since we did not spin on console lock, annotate
-	 * this as a trylock. Otherwise lockdep will
-	 * complain.
-	 */
-	mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
-
-	return 1;
-}
-
-/*
- * Call the console drivers, asking them to write out
- * log_buf[start] to log_buf[end - 1].
- * The console_lock must be held.
- */
-static void call_console_drivers(const char *ext_text, size_t ext_len,
-				 const char *text, size_t len)
-{
-	struct console *con;
-
-	trace_console_rcuidle(text, len);
-
-	for_each_console(con) {
-		if (exclusive_console && con != exclusive_console)
-			continue;
-		if (!(con->flags & CON_ENABLED))
-			continue;
-		if (!con->write)
-			continue;
-		if (!cpu_online(smp_processor_id()) &&
-		    !(con->flags & CON_ANYTIME))
-			continue;
-		if (con->flags & CON_EXTENDED)
-			con->write(con, ext_text, ext_len);
-		else
-			con->write(con, text, len);
-	}
-}
-
 int printk_delay_msec __read_mostly;
 
-static inline void printk_delay(void)
+static inline void printk_delay(int level)
 {
+	boot_delay_msec(level);
 	if (unlikely(printk_delay_msec)) {
 		int m = printk_delay_msec;
 
@@ -1839,6 +1645,170 @@ static inline void printk_delay(void)
 	}
 }
 
+static void print_console_dropped(struct console *con, u64 count)
+{
+	char text[64];
+	int len;
+
+	len = sprintf(text, "** %llu printk message%s dropped **\n",
+		      count, count > 1 ? "s" : "");
+	con->write(con, text, len);
+}
+
+static void format_text(struct printk_log *msg, u64 seq,
+			char *ext_text, size_t *ext_len,
+			char *text, size_t *len, bool time)
+{
+	if (suppress_message_printing(msg->level)) {
+		/*
+		 * Skip record that has level above the console
+		 * loglevel and update each console's local seq.
+		 */
+		*len = 0;
+		*ext_len = 0;
+		return;
+	}
+
+	*len = msg_print_text(msg, console_msg_format & MSG_FORMAT_SYSLOG,
+			      time, text, PRINTK_SPRINT_MAX);
+	if (nr_ext_console_drivers) {
+		*ext_len = msg_print_ext_header(ext_text, CONSOLE_EXT_LOG_MAX,
+						msg, seq);
+		*ext_len += msg_print_ext_body(ext_text + *ext_len,
+					       CONSOLE_EXT_LOG_MAX - *ext_len,
+					       log_dict(msg), msg->dict_len,
+					       log_text(msg), msg->text_len);
+	} else {
+		*ext_len = 0;
+	}
+}
+
+static void printk_write_history(struct console *con, u64 master_seq)
+{
+	struct prb_iterator iter;
+	bool time = printk_time;
+	static char *ext_text;
+	static char *text;
+	static char *buf;
+	u64 seq;
+
+	ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL);
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+	buf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!ext_text || !text || !buf)
+		return;
+
+	if (!(con->flags & CON_ENABLED))
+		goto out;
+
+	if (!con->write)
+		goto out;
+
+	if (!cpu_online(raw_smp_processor_id()) &&
+	    !(con->flags & CON_ANYTIME))
+		goto out;
+
+	prb_iter_init(&iter, &printk_rb, NULL);
+
+	for (;;) {
+		struct printk_log *msg;
+		size_t ext_len;
+		size_t len;
+		int ret;
+
+		ret = prb_iter_next(&iter, buf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		if (seq > master_seq)
+			break;
+
+		con->printk_seq++;
+		if (con->printk_seq < seq) {
+			print_console_dropped(con, seq - con->printk_seq);
+			con->printk_seq = seq;
+		}
+
+		msg = (struct printk_log *)buf;
+		format_text(msg, master_seq, ext_text, &ext_len, text,
+			    &len, time);
+
+		if (len == 0 && ext_len == 0)
+			continue;
+
+		if (con->flags & CON_EXTENDED)
+			con->write(con, ext_text, ext_len);
+		else
+			con->write(con, text, len);
+
+		printk_delay(msg->level);
+	}
+out:
+	con->wrote_history = 1;
+	kfree(ext_text);
+	kfree(text);
+	kfree(buf);
+}
+
+/*
+ * Call the console drivers, asking them to write out
+ * log_buf[start] to log_buf[end - 1].
+ * The console_lock must be held.
+ */
+static void call_console_drivers(u64 seq, const char *ext_text, size_t ext_len,
+				 const char *text, size_t len, int level,
+				 int facility)
+{
+	struct console *con;
+
+	trace_console_rcuidle(text, len);
+
+	for_each_console(con) {
+		if (!(con->flags & CON_ENABLED))
+			continue;
+		if (!con->wrote_history) {
+			if (con->flags & CON_PRINTBUFFER) {
+				printk_write_history(con, seq);
+				continue;
+			}
+			con->wrote_history = 1;
+			con->printk_seq = seq - 1;
+		}
+		if (con->flags & CON_BOOT && facility == 0) {
+			/* skip boot messages, already printed */
+			if (con->printk_seq < seq)
+				con->printk_seq = seq;
+			continue;
+		}
+		if (!con->write)
+			continue;
+		if (!cpu_online(raw_smp_processor_id()) &&
+		    !(con->flags & CON_ANYTIME))
+			continue;
+		if (con->printk_seq >= seq)
+			continue;
+
+		con->printk_seq++;
+		if (con->printk_seq < seq) {
+			print_console_dropped(con, seq - con->printk_seq);
+			con->printk_seq = seq;
+		}
+
+		/* for supressed messages, only seq is updated */
+		if (len == 0 && ext_len == 0)
+			continue;
+
+		if (con->flags & CON_EXTENDED)
+			con->write(con, ext_text, ext_len);
+		else
+			con->write(con, text, len);
+	}
+}
+
 static inline u32 printk_caller_id(void)
 {
 	return in_task() ? task_pid_nr(current) :
@@ -1855,101 +1825,95 @@ static struct cont {
 	char buf[LOG_LINE_MAX];
 	size_t len;			/* length == 0 means unused buffer */
 	u32 caller_id;			/* printk_caller_id() of first print */
+	int cpu_owner;			/* cpu of first print */
 	u64 ts_nsec;			/* time of first print */
 	u8 level;			/* log level of first message */
 	u8 facility;			/* log facility of first message */
 	enum log_flags flags;		/* prefix, newline flags */
-} cont;
+} cont[2];
 
-static void cont_flush(void)
+static void cont_flush(int ctx)
 {
-	if (cont.len == 0)
+	struct cont *c = &cont[ctx];
+
+	if (c->len == 0)
 		return;
 
-	log_store(cont.caller_id, cont.facility, cont.level, cont.flags,
-		  cont.ts_nsec, NULL, 0, cont.buf, cont.len);
-	cont.len = 0;
+	log_store(c->caller_id, c->facility, c->level, c->flags,
+		  c->ts_nsec, c->cpu_owner, NULL, 0, c->buf, c->len);
+	c->len = 0;
 }
 
-static bool cont_add(u32 caller_id, int facility, int level,
+static void cont_add(int ctx, int cpu, u32 caller_id, int facility, int level,
 		     enum log_flags flags, const char *text, size_t len)
 {
+	struct cont *c = &cont[ctx];
+
+	if (cpu != c->cpu_owner || !(flags & LOG_CONT))
+		cont_flush(ctx);
+
 	/* If the line gets too long, split it up in separate records. */
-	if (cont.len + len > sizeof(cont.buf)) {
-		cont_flush();
-		return false;
+	while (c->len + len > sizeof(c->buf))
+		cont_flush(ctx);
+
+	if (!c->len) {
+		c->facility = facility;
+		c->level = level;
+		c->caller_id = caller_id;
+		c->ts_nsec = local_clock();
+		c->flags = flags;
+		c->cpu_owner = cpu;
 	}
 
-	if (!cont.len) {
-		cont.facility = facility;
-		cont.level = level;
-		cont.caller_id = caller_id;
-		cont.ts_nsec = local_clock();
-		cont.flags = flags;
-	}
-
-	memcpy(cont.buf + cont.len, text, len);
-	cont.len += len;
+	memcpy(c->buf + c->len, text, len);
+	c->len += len;
 
 	// The original flags come from the first line,
 	// but later continuations can add a newline.
 	if (flags & LOG_NEWLINE) {
-		cont.flags |= LOG_NEWLINE;
-		cont_flush();
+		c->flags |= LOG_NEWLINE;
+		cont_flush(ctx);
 	}
-
-	return true;
 }
 
-static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len)
+/* ring buffer used as memory allocator for temporary sprint buffers */
+DECLARE_STATIC_PRINTKRB(sprint_rb,
+			ilog2(PRINTK_RECORD_MAX + sizeof(struct prb_entry) +
+			      sizeof(long)) + 2, &printk_cpulock);
+
+asmlinkage int vprintk_emit(int facility, int level,
+			    const char *dict, size_t dictlen,
+			    const char *fmt, va_list args)
 {
 	const u32 caller_id = printk_caller_id();
-
-	/*
-	 * If an earlier line was buffered, and we're a continuation
-	 * write from the same context, try to add it to the buffer.
-	 */
-	if (cont.len) {
-		if (cont.caller_id == caller_id && (lflags & LOG_CONT)) {
-			if (cont_add(caller_id, facility, level, lflags, text, text_len))
-				return text_len;
-		}
-		/* Otherwise, make sure it's flushed */
-		cont_flush();
-	}
-
-	/* Skip empty continuation lines that couldn't be added - they just flush */
-	if (!text_len && (lflags & LOG_CONT))
-		return 0;
-
-	/* If it doesn't end in a newline, try to buffer the current line */
-	if (!(lflags & LOG_NEWLINE)) {
-		if (cont_add(caller_id, facility, level, lflags, text, text_len))
-			return text_len;
-	}
-
-	/* Store it in the record log */
-	return log_store(caller_id, facility, level, lflags, 0,
-			 dict, dictlen, text, text_len);
-}
-
-/* Must be called under logbuf_lock. */
-int vprintk_store(int facility, int level,
-		  const char *dict, size_t dictlen,
-		  const char *fmt, va_list args)
-{
-	static char textbuf[LOG_LINE_MAX];
-	char *text = textbuf;
-	size_t text_len;
+	int ctx = !!in_nmi();
 	enum log_flags lflags = 0;
+	int printed_len = 0;
+	struct prb_handle h;
+	size_t text_len;
+	u64 ts_nsec;
+	char *text;
+	char *rbuf;
+	int cpu;
+
+	ts_nsec = local_clock();
+
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_SPRINT_MAX);
+	if (!rbuf) {
+		prb_inc_lost(&printk_rb);
+		return printed_len;
+	}
+
+	cpu = raw_smp_processor_id();
 
 	/*
-	 * The printf needs to come first; we need the syslog
-	 * prefix which might be passed-in as a parameter.
+	 * If this turns out to be an emergency message, there
+	 * may need to be a prefix added. Leave room for it.
 	 */
-	text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+	text = rbuf + PREFIX_MAX;
+	text_len = vscnprintf(text, PRINTK_SPRINT_MAX - PREFIX_MAX, fmt, args);
 
-	/* mark and strip a trailing newline */
+	/* strip and flag a trailing newline */
 	if (text_len && text[text_len-1] == '\n') {
 		text_len--;
 		lflags |= LOG_NEWLINE;
@@ -1980,62 +1944,37 @@ int vprintk_store(int facility, int level,
 	if (dict)
 		lflags |= LOG_NEWLINE;
 
-	return log_output(facility, level, lflags,
-			  dict, dictlen, text, text_len);
-}
-
-asmlinkage int vprintk_emit(int facility, int level,
-			    const char *dict, size_t dictlen,
-			    const char *fmt, va_list args)
-{
-	int printed_len;
-	bool in_sched = false, pending_output;
-	unsigned long flags;
-	u64 curr_log_seq;
-
-	/* Suppress unimportant messages after panic happens */
-	if (unlikely(suppress_printk))
-		return 0;
-
-	if (level == LOGLEVEL_SCHED) {
-		level = LOGLEVEL_DEFAULT;
-		in_sched = true;
+	/*
+	 * NOTE:
+	 * - rbuf points to beginning of allocated buffer
+	 * - text points to beginning of text
+	 * - there is room before text for prefix
+	 */
+	if (facility == 0) {
+		/* only the kernel can create emergency messages */
+		printk_emergency(rbuf, level & 7, ts_nsec, cpu, text, text_len);
 	}
 
-	boot_delay_msec(level);
-	printk_delay();
-
-	/* This stops the holder of console_sem just where we want him */
-	logbuf_lock_irqsave(flags);
-	curr_log_seq = log_next_seq;
-	printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
-	pending_output = (curr_log_seq != log_next_seq);
-	logbuf_unlock_irqrestore(flags);
-
-	/* If called from the scheduler, we can not call up(). */
-	if (!in_sched && pending_output) {
-		/*
-		 * Disable preemption to avoid being preempted while holding
-		 * console_sem which would prevent anyone from printing to
-		 * console
-		 */
-		preempt_disable();
-		/*
-		 * Try to acquire and then immediately release the console
-		 * semaphore.  The release will print out buffers and wake up
-		 * /dev/kmsg and syslog() users.
-		 */
-		if (console_trylock_spinning())
-			console_unlock();
-		preempt_enable();
+	if ((lflags & LOG_CONT) || !(lflags & LOG_NEWLINE)) {
+		 cont_add(ctx, cpu, caller_id, facility, level, lflags, text, text_len);
+		 printed_len = text_len;
+	} else {
+		if (cpu == cont[ctx].cpu_owner)
+			cont_flush(ctx);
+		printed_len = log_store(caller_id, facility, level, lflags, ts_nsec, cpu,
+					dict, dictlen, text, text_len);
 	}
 
-	if (pending_output)
-		wake_up_klogd();
+	prb_commit(&h);
 	return printed_len;
 }
 EXPORT_SYMBOL(vprintk_emit);
 
+static __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+{
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
+}
+
 asmlinkage int vprintk(const char *fmt, va_list args)
 {
 	return vprintk_func(fmt, args);
@@ -2081,39 +2020,6 @@ asmlinkage __visible int printk(const char *fmt, ...)
 	return r;
 }
 EXPORT_SYMBOL(printk);
-
-#else /* CONFIG_PRINTK */
-
-#define LOG_LINE_MAX		0
-#define PREFIX_MAX		0
-#define printk_time		false
-
-static u64 syslog_seq;
-static u32 syslog_idx;
-static u64 console_seq;
-static u32 console_idx;
-static u64 exclusive_console_stop_seq;
-static u64 log_first_seq;
-static u32 log_first_idx;
-static u64 log_next_seq;
-static char *log_text(const struct printk_log *msg) { return NULL; }
-static char *log_dict(const struct printk_log *msg) { return NULL; }
-static struct printk_log *log_from_idx(u32 idx) { return NULL; }
-static u32 log_next(u32 idx) { return 0; }
-static ssize_t msg_print_ext_header(char *buf, size_t size,
-				    struct printk_log *msg,
-				    u64 seq) { return 0; }
-static ssize_t msg_print_ext_body(char *buf, size_t size,
-				  char *dict, size_t dict_len,
-				  char *text, size_t text_len) { return 0; }
-static void console_lock_spinning_enable(void) { }
-static int console_lock_spinning_disable_and_check(void) { return 0; }
-static void call_console_drivers(const char *ext_text, size_t ext_len,
-				 const char *text, size_t len) {}
-static size_t msg_print_text(const struct printk_log *msg, bool syslog,
-			     bool time, char *buf, size_t size) { return 0; }
-static bool suppress_message_printing(int level) { return false; }
-
 #endif /* CONFIG_PRINTK */
 
 #ifdef CONFIG_EARLY_PRINTK
@@ -2350,187 +2256,24 @@ int is_console_locked(void)
 }
 EXPORT_SYMBOL(is_console_locked);
 
-/*
- * Check if we have any console that is capable of printing while cpu is
- * booting or shutting down. Requires console_sem.
- */
-static int have_callable_console(void)
-{
-	struct console *con;
-
-	for_each_console(con)
-		if ((con->flags & CON_ENABLED) &&
-				(con->flags & CON_ANYTIME))
-			return 1;
-
-	return 0;
-}
-
-/*
- * Can we actually use the console at this time on this cpu?
- *
- * Console drivers may assume that per-cpu resources have been allocated. So
- * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't
- * call them until this CPU is officially up.
- */
-static inline int can_use_console(void)
-{
-	return cpu_online(raw_smp_processor_id()) || have_callable_console();
-}
-
 /**
  * console_unlock - unlock the console system
  *
  * Releases the console_lock which the caller holds on the console system
  * and the console driver list.
  *
- * While the console_lock was held, console output may have been buffered
- * by printk().  If this is the case, console_unlock(); emits
- * the output prior to releasing the lock.
- *
- * If there is output waiting, we wake /dev/kmsg and syslog() users.
- *
  * console_unlock(); may be called from any context.
  */
 void console_unlock(void)
 {
-	static char ext_text[CONSOLE_EXT_LOG_MAX];
-	static char text[LOG_LINE_MAX + PREFIX_MAX];
-	unsigned long flags;
-	bool do_cond_resched, retry;
-
 	if (console_suspended) {
 		up_console_sem();
 		return;
 	}
 
-	/*
-	 * Console drivers are called with interrupts disabled, so
-	 * @console_may_schedule should be cleared before; however, we may
-	 * end up dumping a lot of lines, for example, if called from
-	 * console registration path, and should invoke cond_resched()
-	 * between lines if allowable.  Not doing so can cause a very long
-	 * scheduling stall on a slow console leading to RCU stall and
-	 * softlockup warnings which exacerbate the issue with more
-	 * messages practically incapacitating the system.
-	 *
-	 * console_trylock() is not able to detect the preemptive
-	 * context reliably. Therefore the value must be stored before
-	 * and cleared after the the "again" goto label.
-	 */
-	do_cond_resched = console_may_schedule;
-again:
-	console_may_schedule = 0;
-
-	/*
-	 * We released the console_sem lock, so we need to recheck if
-	 * cpu is online and (if not) is there at least one CON_ANYTIME
-	 * console.
-	 */
-	if (!can_use_console()) {
-		console_locked = 0;
-		up_console_sem();
-		return;
-	}
-
-	for (;;) {
-		struct printk_log *msg;
-		size_t ext_len = 0;
-		size_t len;
-
-		printk_safe_enter_irqsave(flags);
-		raw_spin_lock(&logbuf_lock);
-		if (console_seq < log_first_seq) {
-			len = snprintf(text, sizeof(text),
-				       "** %llu printk messages dropped **\n",
-				       log_first_seq - console_seq);
-
-			/* messages are gone, move to first one */
-			console_seq = log_first_seq;
-			console_idx = log_first_idx;
-		} else {
-			len = 0;
-		}
-skip:
-		if (console_seq == log_next_seq)
-			break;
-
-		msg = log_from_idx(console_idx);
-		if (suppress_message_printing(msg->level)) {
-			/*
-			 * Skip record we have buffered and already printed
-			 * directly to the console when we received it, and
-			 * record that has level above the console loglevel.
-			 */
-			console_idx = log_next(console_idx);
-			console_seq++;
-			goto skip;
-		}
-
-		/* Output to all consoles once old messages replayed. */
-		if (unlikely(exclusive_console &&
-			     console_seq >= exclusive_console_stop_seq)) {
-			exclusive_console = NULL;
-		}
-
-		len += msg_print_text(msg,
-				console_msg_format & MSG_FORMAT_SYSLOG,
-				printk_time, text + len, sizeof(text) - len);
-		if (nr_ext_console_drivers) {
-			ext_len = msg_print_ext_header(ext_text,
-						sizeof(ext_text),
-						msg, console_seq);
-			ext_len += msg_print_ext_body(ext_text + ext_len,
-						sizeof(ext_text) - ext_len,
-						log_dict(msg), msg->dict_len,
-						log_text(msg), msg->text_len);
-		}
-		console_idx = log_next(console_idx);
-		console_seq++;
-		raw_spin_unlock(&logbuf_lock);
-
-		/*
-		 * While actively printing out messages, if another printk()
-		 * were to occur on another CPU, it may wait for this one to
-		 * finish. This task can not be preempted if there is a
-		 * waiter waiting to take over.
-		 */
-		console_lock_spinning_enable();
-
-		stop_critical_timings();	/* don't trace print latency */
-		call_console_drivers(ext_text, ext_len, text, len);
-		start_critical_timings();
-
-		if (console_lock_spinning_disable_and_check()) {
-			printk_safe_exit_irqrestore(flags);
-			return;
-		}
-
-		printk_safe_exit_irqrestore(flags);
-
-		if (do_cond_resched)
-			cond_resched();
-	}
-
 	console_locked = 0;
 
-	raw_spin_unlock(&logbuf_lock);
-
 	up_console_sem();
-
-	/*
-	 * Someone could have filled up the buffer again, so re-check if there's
-	 * something to flush. In case we cannot trylock the console_sem again,
-	 * there's a new owner and the console_unlock() from them will do the
-	 * flush, no worries.
-	 */
-	raw_spin_lock(&logbuf_lock);
-	retry = console_seq != log_next_seq;
-	raw_spin_unlock(&logbuf_lock);
-	printk_safe_exit_irqrestore(flags);
-
-	if (retry && console_trylock())
-		goto again;
 }
 EXPORT_SYMBOL(console_unlock);
 
@@ -2581,24 +2324,10 @@ void console_unblank(void)
 void console_flush_on_panic(enum con_flush_mode mode)
 {
 	/*
-	 * If someone else is holding the console lock, trylock will fail
-	 * and may_schedule may be set.  Ignore and proceed to unlock so
-	 * that messages are flushed out.  As this can be called from any
-	 * context and we don't want to get preempted while flushing,
-	 * ensure may_schedule is cleared.
+	 * FIXME: This is currently a NOP. Emergency messages will have been
+	 * printed, but what about if write_atomic is not available on the
+	 * console? What if the printk kthread is still alive?
 	 */
-	console_trylock();
-	console_may_schedule = 0;
-
-	if (mode == CONSOLE_REPLAY_ALL) {
-		unsigned long flags;
-
-		logbuf_lock_irqsave(flags);
-		console_seq = log_first_seq;
-		console_idx = log_first_idx;
-		logbuf_unlock_irqrestore(flags);
-	}
-	console_unlock();
 }
 
 /*
@@ -2732,7 +2461,6 @@ static int try_enable_new_console(struct console *newcon, bool user_specified)
  */
 void register_console(struct console *newcon)
 {
-	unsigned long flags;
 	struct console *bcon = NULL;
 	int err;
 
@@ -2820,27 +2548,6 @@ void register_console(struct console *newcon)
 	if (newcon->flags & CON_EXTENDED)
 		nr_ext_console_drivers++;
 
-	if (newcon->flags & CON_PRINTBUFFER) {
-		/*
-		 * console_unlock(); will print out the buffered messages
-		 * for us.
-		 */
-		logbuf_lock_irqsave(flags);
-		/*
-		 * We're about to replay the log buffer.  Only do this to the
-		 * just-registered console to avoid excessive message spam to
-		 * the already-registered consoles.
-		 *
-		 * Set exclusive_console with disabled interrupts to reduce
-		 * race window with eventual console_flush_on_panic() that
-		 * ignores console_lock.
-		 */
-		exclusive_console = newcon;
-		exclusive_console_stop_seq = console_seq;
-		console_seq = syslog_seq;
-		console_idx = syslog_idx;
-		logbuf_unlock_irqrestore(flags);
-	}
 	console_unlock();
 	console_sysfs_notify();
 
@@ -2850,6 +2557,10 @@ void register_console(struct console *newcon)
 	 * boot consoles, real consoles, etc - this is to ensure that end
 	 * users know there might be something in the kernel's log buffer that
 	 * went to the bootconsole (that they do not see on the real console)
+	 *
+	 * This message is also important because it will trigger the
+	 * printk kthread to begin dumping the log buffer to the newly
+	 * registered console.
 	 */
 	pr_info("%sconsole [%s%d] enabled\n",
 		(newcon->flags & CON_BOOT) ? "boot" : "" ,
@@ -3007,65 +2718,75 @@ static int __init printk_late_init(void)
 late_initcall(printk_late_init);
 
 #if defined CONFIG_PRINTK
-/*
- * Delayed printk version, for scheduler-internal messages:
- */
-#define PRINTK_PENDING_WAKEUP	0x01
-#define PRINTK_PENDING_OUTPUT	0x02
-
-static DEFINE_PER_CPU(int, printk_pending);
-
-static void wake_up_klogd_work_func(struct irq_work *irq_work)
+static int printk_kthread_func(void *data)
 {
-	int pending = __this_cpu_xchg(printk_pending, 0);
+	struct prb_iterator iter;
+	struct printk_log *msg;
+	size_t ext_len;
+	char *ext_text;
+	u64 master_seq;
+	size_t len;
+	char *text;
+	char *buf;
+	int ret;
 
-	if (pending & PRINTK_PENDING_OUTPUT) {
-		/* If trylock fails, someone else is doing the printing */
-		if (console_trylock())
-			console_unlock();
+	ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL);
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+	buf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!ext_text || !text || !buf)
+		return -1;
+
+	prb_iter_init(&iter, &printk_rb, NULL);
+
+	/* the printk kthread never exits */
+	for (;;) {
+		ret = prb_iter_wait_next(&iter, buf,
+					 PRINTK_RECORD_MAX, &master_seq);
+		if (ret == -ERESTARTSYS) {
+			continue;
+		} else if (ret < 0) {
+			/* iterator invalid, start over */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		msg = (struct printk_log *)buf;
+		format_text(msg, master_seq, ext_text, &ext_len, text,
+			    &len, printk_time);
+
+		console_lock();
+		console_may_schedule = 0;
+		call_console_drivers(master_seq, ext_text, ext_len, text, len,
+				     msg->level, msg->facility);
+		if (len > 0 || ext_len > 0)
+			printk_delay(msg->level);
+		console_unlock();
 	}
 
-	if (pending & PRINTK_PENDING_WAKEUP)
-		wake_up_interruptible(&log_wait);
+	kfree(ext_text);
+	kfree(text);
+	kfree(buf);
+
+	return 0;
 }
 
-static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
-	.func = wake_up_klogd_work_func,
-	.flags = ATOMIC_INIT(IRQ_WORK_LAZY),
-};
-
-void wake_up_klogd(void)
+static int __init init_printk_kthread(void)
 {
-	if (!printk_percpu_data_ready())
-		return;
+	struct task_struct *thread;
 
-	preempt_disable();
-	if (waitqueue_active(&log_wait)) {
-		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
-		irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
+	thread = kthread_run(printk_kthread_func, NULL, "printk");
+	if (IS_ERR(thread)) {
+		pr_err("printk: unable to create printing thread\n");
+		return PTR_ERR(thread);
 	}
-	preempt_enable();
+
+	return 0;
 }
+late_initcall(init_printk_kthread);
 
-void defer_console_output(void)
+static int vprintk_deferred(const char *fmt, va_list args)
 {
-	if (!printk_percpu_data_ready())
-		return;
-
-	preempt_disable();
-	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
-	irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
-	preempt_enable();
-}
-
-int vprintk_deferred(const char *fmt, va_list args)
-{
-	int r;
-
-	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
-	defer_console_output();
-
-	return r;
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
 }
 
 int printk_deferred(const char *fmt, ...)
@@ -3204,8 +2925,8 @@ EXPORT_SYMBOL_GPL(kmsg_dump_reason_str);
  */
 void kmsg_dump(enum kmsg_dump_reason reason)
 {
+	struct kmsg_dumper dumper_local;
 	struct kmsg_dumper *dumper;
-	unsigned long flags;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(dumper, &dump_list, list) {
@@ -3222,21 +2943,18 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 		if (reason > max_reason)
 			continue;
 
-		/* initialize iterator with data about the stored records */
-		dumper->active = true;
+		/*
+		 * use a local copy to avoid modifying the
+		 * iterator used by any other cpus/contexts
+		 */
+		memcpy(&dumper_local, dumper, sizeof(dumper_local));
 
-		logbuf_lock_irqsave(flags);
-		dumper->cur_seq = clear_seq;
-		dumper->cur_idx = clear_idx;
-		dumper->next_seq = log_next_seq;
-		dumper->next_idx = log_next_idx;
-		logbuf_unlock_irqrestore(flags);
+		/* initialize iterator with data about the stored records */
+		dumper_local.active = true;
+		kmsg_dump_rewind(&dumper_local);
 
 		/* invoke dumper which will iterate over records */
-		dumper->dump(dumper, reason);
-
-		/* reset iterator */
-		dumper->active = false;
+		dumper_local.dump(&dumper_local, reason);
 	}
 	rcu_read_unlock();
 }
@@ -3263,33 +2981,67 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
 			       char *line, size_t size, size_t *len)
 {
+	struct prb_iterator iter;
 	struct printk_log *msg;
-	size_t l = 0;
-	bool ret = false;
+	struct prb_handle h;
+	bool cont = false;
+	char *msgbuf;
+	char *rbuf;
+	size_t l;
+	u64 seq;
+	int ret;
 
 	if (!dumper->active)
-		goto out;
+		return cont;
 
-	if (dumper->cur_seq < log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = log_first_seq;
-		dumper->cur_idx = log_first_idx;
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_RECORD_MAX);
+	if (!rbuf)
+		return cont;
+	msgbuf = rbuf;
+retry:
+	for (;;) {
+		prb_iter_init(&iter, &printk_rb, &seq);
+
+		if (dumper->line_seq == seq) {
+			/* already where we want to be */
+			break;
+		} else if (dumper->line_seq < seq) {
+			/* messages are gone, move to first available one */
+			dumper->line_seq = seq;
+			break;
+		}
+
+		ret = prb_iter_seek(&iter, dumper->line_seq);
+		if (ret > 0) {
+			/* seeked to line_seq */
+			break;
+		} else if (ret == 0) {
+			/*
+			 * The end of the list was hit without ever seeing
+			 * line_seq. Reset it to the beginning of the list.
+			 */
+			prb_iter_init(&iter, &printk_rb, &dumper->line_seq);
+			break;
+		}
+		/* iterator invalid, start over */
 	}
 
-	/* last entry */
-	if (dumper->cur_seq >= log_next_seq)
+	ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX,
+			    &dumper->line_seq);
+	if (ret == 0)
 		goto out;
+	else if (ret < 0)
+		goto retry;
 
-	msg = log_from_idx(dumper->cur_idx);
+	msg = (struct printk_log *)msgbuf;
 	l = msg_print_text(msg, syslog, printk_time, line, size);
 
-	dumper->cur_idx = log_next(dumper->cur_idx);
-	dumper->cur_seq++;
-	ret = true;
-out:
 	if (len)
 		*len = l;
-	return ret;
+	cont = true;
+out:
+	prb_commit(&h);
+	return cont;
 }
 
 /**
@@ -3312,12 +3064,9 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
 			char *line, size_t size, size_t *len)
 {
-	unsigned long flags;
 	bool ret;
 
-	logbuf_lock_irqsave(flags);
 	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
-	logbuf_unlock_irqrestore(flags);
 
 	return ret;
 }
@@ -3345,74 +3094,101 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
 			  char *buf, size_t size, size_t *len)
 {
-	unsigned long flags;
-	u64 seq;
-	u32 idx;
-	u64 next_seq;
-	u32 next_idx;
-	size_t l = 0;
-	bool ret = false;
+	struct prb_iterator iter;
 	bool time = printk_time;
+	struct printk_log *msg;
+	u64 new_end_seq = 0;
+	struct prb_handle h;
+	bool cont = false;
+	char *msgbuf;
+	u64 end_seq;
+	int textlen;
+	u64 seq = 0;
+	char *rbuf;
+	int l = 0;
+	int ret;
 
 	if (!dumper->active)
+		return cont;
+
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_RECORD_MAX);
+	if (!rbuf)
+		return cont;
+	msgbuf = rbuf;
+
+	prb_iter_init(&iter, &printk_rb, NULL);
+
+	/*
+	 * seek to the start record, which is set/modified
+	 * by kmsg_dump_get_line_nolock()
+	 */
+	ret = prb_iter_seek(&iter, dumper->line_seq);
+	if (ret <= 0)
+		prb_iter_init(&iter, &printk_rb, &seq);
+
+	/* work with a local end seq to have a constant value */
+	end_seq = dumper->buffer_end_seq;
+	if (!end_seq) {
+		/* initialize end seq to "infinity" */
+		end_seq = -1;
+		dumper->buffer_end_seq = end_seq;
+	}
+retry:
+	if (seq >= end_seq)
 		goto out;
 
-	logbuf_lock_irqsave(flags);
-	if (dumper->cur_seq < log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = log_first_seq;
-		dumper->cur_idx = log_first_idx;
+	/* count the total bytes after seq */
+	textlen = count_remaining(&iter, end_seq, msgbuf,
+				  PRINTK_RECORD_MAX, 0, time);
+
+	/* move iter forward until length fits into the buffer */
+	while (textlen > size) {
+		ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0 || seq >= end_seq) {
+			prb_iter_init(&iter, &printk_rb, &seq);
+			goto retry;
+		}
+
+		msg = (struct printk_log *)msgbuf;
+		textlen -= msg_print_text(msg, true, time, NULL, 0);
 	}
 
-	/* last entry */
-	if (dumper->cur_seq >= dumper->next_seq) {
-		logbuf_unlock_irqrestore(flags);
-		goto out;
+	/* save end seq for the next interation */
+	new_end_seq = seq + 1;
+
+	/* copy messages to buffer */
+	while (l < size) {
+		ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * iterator (and thus also the start position)
+			 * invalid, start over from beginning of list
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		if (seq >= end_seq)
+			break;
+
+		msg = (struct printk_log *)msgbuf;
+		textlen = msg_print_text(msg, syslog, time, buf + l, size - l);
+		if (textlen > 0)
+			l += textlen;
+		cont = true;
 	}
 
-	/* calculate length of entire buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		l += msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	/* move first record forward until length fits into the buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	while (l >= size && seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		l -= msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	/* last message in next interation */
-	next_seq = seq;
-	next_idx = idx;
-
-	l = 0;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		l += msg_print_text(msg, syslog, time, buf + l, size - l);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	dumper->next_seq = next_seq;
-	dumper->next_idx = next_idx;
-	ret = true;
-	logbuf_unlock_irqrestore(flags);
-out:
-	if (len)
+	if (cont && len)
 		*len = l;
-	return ret;
+out:
+	prb_commit(&h);
+	if (new_end_seq)
+		dumper->buffer_end_seq = new_end_seq;
+	return cont;
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
 
@@ -3428,10 +3204,8 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
  */
 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
 {
-	dumper->cur_seq = clear_seq;
-	dumper->cur_idx = clear_idx;
-	dumper->next_seq = log_next_seq;
-	dumper->next_idx = log_next_idx;
+	dumper->line_seq = 0;
+	dumper->buffer_end_seq = 0;
 }
 
 /**
@@ -3444,12 +3218,89 @@ void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
  */
 void kmsg_dump_rewind(struct kmsg_dumper *dumper)
 {
-	unsigned long flags;
-
-	logbuf_lock_irqsave(flags);
 	kmsg_dump_rewind_nolock(dumper);
-	logbuf_unlock_irqrestore(flags);
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 
+static bool console_can_emergency(int level)
+{
+	struct console *con;
+
+	for_each_console(con) {
+		if (!(con->flags & CON_ENABLED))
+			continue;
+		if (con->write_atomic && oops_in_progress)
+			return true;
+		if (con->write && (con->flags & CON_BOOT))
+			return true;
+	}
+	return false;
+}
+
+static void call_emergency_console_drivers(int level, const char *text,
+					   size_t text_len)
+{
+	struct console *con;
+
+	for_each_console(con) {
+		if (!(con->flags & CON_ENABLED))
+			continue;
+		if (con->write_atomic && oops_in_progress) {
+			con->write_atomic(con, text, text_len);
+			continue;
+		}
+		if (con->write && (con->flags & CON_BOOT)) {
+			con->write(con, text, text_len);
+			continue;
+		}
+	}
+}
+
+static void printk_emergency(char *buffer, int level, u64 ts_nsec, u16 cpu,
+			     char *text, u16 text_len)
+{
+	struct printk_log msg;
+	size_t prefix_len;
+
+	if (!console_can_emergency(level))
+		return;
+
+	msg.level = level;
+	msg.ts_nsec = ts_nsec;
+	msg.cpu = cpu;
+	msg.facility = 0;
+
+	/* "text" must have PREFIX_MAX preceding bytes available */
+
+	prefix_len = print_prefix(&msg,
+				  console_msg_format & MSG_FORMAT_SYSLOG,
+				  printk_time, buffer);
+	/* move the prefix forward to the beginning of the message text */
+	text -= prefix_len;
+	memmove(text, buffer, prefix_len);
+	text_len += prefix_len;
+
+	text[text_len++] = '\n';
+
+	call_emergency_console_drivers(level, text, text_len);
+
+	touch_softlockup_watchdog_sync();
+	clocksource_touch_watchdog();
+	rcu_cpu_stall_reset();
+	touch_nmi_watchdog();
+
+	printk_delay(level);
+}
 #endif
+
+void console_atomic_lock(unsigned int *flags)
+{
+	prb_lock(&printk_cpulock, flags);
+}
+EXPORT_SYMBOL(console_atomic_lock);
+
+void console_atomic_unlock(unsigned int flags)
+{
+	prb_unlock(&printk_cpulock, flags);
+}
+EXPORT_SYMBOL(console_atomic_unlock);
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
deleted file mode 100644
index 50aeae7704346..0000000000000
--- a/kernel/printk/printk_safe.c
+++ /dev/null
@@ -1,414 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * printk_safe.c - Safe printk for printk-deadlock-prone contexts
- */
-
-#include <linux/preempt.h>
-#include <linux/spinlock.h>
-#include <linux/debug_locks.h>
-#include <linux/kdb.h>
-#include <linux/smp.h>
-#include <linux/cpumask.h>
-#include <linux/irq_work.h>
-#include <linux/printk.h>
-#include <linux/kprobes.h>
-
-#include "internal.h"
-
-/*
- * printk() could not take logbuf_lock in NMI context. Instead,
- * it uses an alternative implementation that temporary stores
- * the strings into a per-CPU buffer. The content of the buffer
- * is later flushed into the main ring buffer via IRQ work.
- *
- * The alternative implementation is chosen transparently
- * by examinig current printk() context mask stored in @printk_context
- * per-CPU variable.
- *
- * The implementation allows to flush the strings also from another CPU.
- * There are situations when we want to make sure that all buffers
- * were handled or when IRQs are blocked.
- */
-
-#define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) -	\
-				sizeof(atomic_t) -			\
-				sizeof(atomic_t) -			\
-				sizeof(struct irq_work))
-
-struct printk_safe_seq_buf {
-	atomic_t		len;	/* length of written data */
-	atomic_t		message_lost;
-	struct irq_work		work;	/* IRQ work that flushes the buffer */
-	unsigned char		buffer[SAFE_LOG_BUF_LEN];
-};
-
-static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq);
-static DEFINE_PER_CPU(int, printk_context);
-
-#ifdef CONFIG_PRINTK_NMI
-static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq);
-#endif
-
-/* Get flushed in a more safe context. */
-static void queue_flush_work(struct printk_safe_seq_buf *s)
-{
-	if (printk_percpu_data_ready())
-		irq_work_queue(&s->work);
-}
-
-/*
- * Add a message to per-CPU context-dependent buffer. NMI and printk-safe
- * have dedicated buffers, because otherwise printk-safe preempted by
- * NMI-printk would have overwritten the NMI messages.
- *
- * The messages are flushed from irq work (or from panic()), possibly,
- * from other CPU, concurrently with printk_safe_log_store(). Should this
- * happen, printk_safe_log_store() will notice the buffer->len mismatch
- * and repeat the write.
- */
-static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
-						const char *fmt, va_list args)
-{
-	int add;
-	size_t len;
-	va_list ap;
-
-again:
-	len = atomic_read(&s->len);
-
-	/* The trailing '\0' is not counted into len. */
-	if (len >= sizeof(s->buffer) - 1) {
-		atomic_inc(&s->message_lost);
-		queue_flush_work(s);
-		return 0;
-	}
-
-	/*
-	 * Make sure that all old data have been read before the buffer
-	 * was reset. This is not needed when we just append data.
-	 */
-	if (!len)
-		smp_rmb();
-
-	va_copy(ap, args);
-	add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap);
-	va_end(ap);
-	if (!add)
-		return 0;
-
-	/*
-	 * Do it once again if the buffer has been flushed in the meantime.
-	 * Note that atomic_cmpxchg() is an implicit memory barrier that
-	 * makes sure that the data were written before updating s->len.
-	 */
-	if (atomic_cmpxchg(&s->len, len, len + add) != len)
-		goto again;
-
-	queue_flush_work(s);
-	return add;
-}
-
-static inline void printk_safe_flush_line(const char *text, int len)
-{
-	/*
-	 * Avoid any console drivers calls from here, because we may be
-	 * in NMI or printk_safe context (when in panic). The messages
-	 * must go only into the ring buffer at this stage.  Consoles will
-	 * get explicitly called later when a crashdump is not generated.
-	 */
-	printk_deferred("%.*s", len, text);
-}
-
-/* printk part of the temporary buffer line by line */
-static int printk_safe_flush_buffer(const char *start, size_t len)
-{
-	const char *c, *end;
-	bool header;
-
-	c = start;
-	end = start + len;
-	header = true;
-
-	/* Print line by line. */
-	while (c < end) {
-		if (*c == '\n') {
-			printk_safe_flush_line(start, c - start + 1);
-			start = ++c;
-			header = true;
-			continue;
-		}
-
-		/* Handle continuous lines or missing new line. */
-		if ((c + 1 < end) && printk_get_level(c)) {
-			if (header) {
-				c = printk_skip_level(c);
-				continue;
-			}
-
-			printk_safe_flush_line(start, c - start);
-			start = c++;
-			header = true;
-			continue;
-		}
-
-		header = false;
-		c++;
-	}
-
-	/* Check if there was a partial line. Ignore pure header. */
-	if (start < end && !header) {
-		static const char newline[] = KERN_CONT "\n";
-
-		printk_safe_flush_line(start, end - start);
-		printk_safe_flush_line(newline, strlen(newline));
-	}
-
-	return len;
-}
-
-static void report_message_lost(struct printk_safe_seq_buf *s)
-{
-	int lost = atomic_xchg(&s->message_lost, 0);
-
-	if (lost)
-		printk_deferred("Lost %d message(s)!\n", lost);
-}
-
-/*
- * Flush data from the associated per-CPU buffer. The function
- * can be called either via IRQ work or independently.
- */
-static void __printk_safe_flush(struct irq_work *work)
-{
-	static raw_spinlock_t read_lock =
-		__RAW_SPIN_LOCK_INITIALIZER(read_lock);
-	struct printk_safe_seq_buf *s =
-		container_of(work, struct printk_safe_seq_buf, work);
-	unsigned long flags;
-	size_t len;
-	int i;
-
-	/*
-	 * The lock has two functions. First, one reader has to flush all
-	 * available message to make the lockless synchronization with
-	 * writers easier. Second, we do not want to mix messages from
-	 * different CPUs. This is especially important when printing
-	 * a backtrace.
-	 */
-	raw_spin_lock_irqsave(&read_lock, flags);
-
-	i = 0;
-more:
-	len = atomic_read(&s->len);
-
-	/*
-	 * This is just a paranoid check that nobody has manipulated
-	 * the buffer an unexpected way. If we printed something then
-	 * @len must only increase. Also it should never overflow the
-	 * buffer size.
-	 */
-	if ((i && i >= len) || len > sizeof(s->buffer)) {
-		const char *msg = "printk_safe_flush: internal error\n";
-
-		printk_safe_flush_line(msg, strlen(msg));
-		len = 0;
-	}
-
-	if (!len)
-		goto out; /* Someone else has already flushed the buffer. */
-
-	/* Make sure that data has been written up to the @len */
-	smp_rmb();
-	i += printk_safe_flush_buffer(s->buffer + i, len - i);
-
-	/*
-	 * Check that nothing has got added in the meantime and truncate
-	 * the buffer. Note that atomic_cmpxchg() is an implicit memory
-	 * barrier that makes sure that the data were copied before
-	 * updating s->len.
-	 */
-	if (atomic_cmpxchg(&s->len, len, 0) != len)
-		goto more;
-
-out:
-	report_message_lost(s);
-	raw_spin_unlock_irqrestore(&read_lock, flags);
-}
-
-/**
- * printk_safe_flush - flush all per-cpu nmi buffers.
- *
- * The buffers are flushed automatically via IRQ work. This function
- * is useful only when someone wants to be sure that all buffers have
- * been flushed at some point.
- */
-void printk_safe_flush(void)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-#ifdef CONFIG_PRINTK_NMI
-		__printk_safe_flush(&per_cpu(nmi_print_seq, cpu).work);
-#endif
-		__printk_safe_flush(&per_cpu(safe_print_seq, cpu).work);
-	}
-}
-
-/**
- * printk_safe_flush_on_panic - flush all per-cpu nmi buffers when the system
- *	goes down.
- *
- * Similar to printk_safe_flush() but it can be called even in NMI context when
- * the system goes down. It does the best effort to get NMI messages into
- * the main ring buffer.
- *
- * Note that it could try harder when there is only one CPU online.
- */
-void printk_safe_flush_on_panic(void)
-{
-	/*
-	 * Make sure that we could access the main ring buffer.
-	 * Do not risk a double release when more CPUs are up.
-	 */
-	if (raw_spin_is_locked(&logbuf_lock)) {
-		if (num_online_cpus() > 1)
-			return;
-
-		debug_locks_off();
-		raw_spin_lock_init(&logbuf_lock);
-	}
-
-	printk_safe_flush();
-}
-
-#ifdef CONFIG_PRINTK_NMI
-/*
- * Safe printk() for NMI context. It uses a per-CPU buffer to
- * store the message. NMIs are not nested, so there is always only
- * one writer running. But the buffer might get flushed from another
- * CPU, so we need to be careful.
- */
-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
-{
-	struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq);
-
-	return printk_safe_log_store(s, fmt, args);
-}
-
-void noinstr printk_nmi_enter(void)
-{
-	this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
-}
-
-void noinstr printk_nmi_exit(void)
-{
-	this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
-}
-
-/*
- * Marks a code that might produce many messages in NMI context
- * and the risk of losing them is more critical than eventual
- * reordering.
- *
- * It has effect only when called in NMI context. Then printk()
- * will try to store the messages into the main logbuf directly
- * and use the per-CPU buffers only as a fallback when the lock
- * is not available.
- */
-void printk_nmi_direct_enter(void)
-{
-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
-		this_cpu_or(printk_context, PRINTK_NMI_DIRECT_CONTEXT_MASK);
-}
-
-void printk_nmi_direct_exit(void)
-{
-	this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK);
-}
-
-#else
-
-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
-{
-	return 0;
-}
-
-#endif /* CONFIG_PRINTK_NMI */
-
-/*
- * Lock-less printk(), to avoid deadlocks should the printk() recurse
- * into itself. It uses a per-CPU buffer to store the message, just like
- * NMI.
- */
-static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args)
-{
-	struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq);
-
-	return printk_safe_log_store(s, fmt, args);
-}
-
-/* Can be preempted by NMI. */
-void __printk_safe_enter(void)
-{
-	this_cpu_inc(printk_context);
-}
-
-/* Can be preempted by NMI. */
-void __printk_safe_exit(void)
-{
-	this_cpu_dec(printk_context);
-}
-
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args)
-{
-#ifdef CONFIG_KGDB_KDB
-	/* Allow to pass printk() to kdb but avoid a recursion. */
-	if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0))
-		return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
-#endif
-
-	/*
-	 * Try to use the main logbuf even in NMI. But avoid calling console
-	 * drivers that might have their own locks.
-	 */
-	if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK) &&
-	    raw_spin_trylock(&logbuf_lock)) {
-		int len;
-
-		len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
-		raw_spin_unlock(&logbuf_lock);
-		defer_console_output();
-		return len;
-	}
-
-	/* Use extra buffer in NMI when logbuf_lock is taken or in safe mode. */
-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
-		return vprintk_nmi(fmt, args);
-
-	/* Use extra buffer to prevent a recursion deadlock in safe mode. */
-	if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK)
-		return vprintk_safe(fmt, args);
-
-	/* No obstacles. */
-	return vprintk_default(fmt, args);
-}
-
-void __init printk_safe_init(void)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-		struct printk_safe_seq_buf *s;
-
-		s = &per_cpu(safe_print_seq, cpu);
-		init_irq_work(&s->work, __printk_safe_flush);
-
-#ifdef CONFIG_PRINTK_NMI
-		s = &per_cpu(nmi_print_seq, cpu);
-		init_irq_work(&s->work, __printk_safe_flush);
-#endif
-	}
-
-	/* Flush pending messages that did not have scheduled IRQ works. */
-	printk_safe_flush();
-}
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 43d6179508d64..3075006d720e6 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -180,7 +180,14 @@ static bool ptrace_freeze_traced(struct task_struct *task)
 
 	spin_lock_irq(&task->sighand->siglock);
 	if (task_is_traced(task) && !__fatal_signal_pending(task)) {
-		task->state = __TASK_TRACED;
+		unsigned long flags;
+
+		raw_spin_lock_irqsave(&task->pi_lock, flags);
+		if (task->state & __TASK_TRACED)
+			task->state = __TASK_TRACED;
+		else
+			task->saved_state = __TASK_TRACED;
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 		ret = true;
 	}
 	spin_unlock_irq(&task->sighand->siglock);
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index 0ebe15a849856..046974b22b8f6 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -186,8 +186,8 @@ config RCU_FAST_NO_HZ
 
 config RCU_BOOST
 	bool "Enable RCU priority boosting"
-	depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
-	default n
+	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
+	default y if PREEMPT_RT
 	help
 	  This option boosts the priority of preempted RCU readers that
 	  block the current preemptible RCU grace period for too long.
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f453bf8d2f1ef..a046e0c84db96 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -74,10 +74,13 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com> and Josh Triplett <josh@
 #define RCUTORTURE_RDR_RBH	 0x08	/*  ... rcu_read_lock_bh(). */
 #define RCUTORTURE_RDR_SCHED	 0x10	/*  ... rcu_read_lock_sched(). */
 #define RCUTORTURE_RDR_RCU	 0x20	/*  ... entering another RCU reader. */
-#define RCUTORTURE_RDR_NBITS	 6	/* Number of bits defined above. */
+#define RCUTORTURE_RDR_ATOM_BH	 0x40	/*  ... disabling bh while atomic */
+#define RCUTORTURE_RDR_ATOM_RBH	 0x80	/*  ... RBH while atomic */
+#define RCUTORTURE_RDR_NBITS	 8	/* Number of bits defined above. */
 #define RCUTORTURE_MAX_EXTEND	 \
 	(RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
-	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
+	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED | \
+	 RCUTORTURE_RDR_ATOM_BH | RCUTORTURE_RDR_ATOM_RBH)
 #define RCUTORTURE_RDR_MAX_LOOPS 0x7	/* Maximum reader extensions. */
 					/* Must be power of two minus one. */
 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
@@ -1246,31 +1249,53 @@ static void rcutorture_one_extend(int *readstate, int newstate,
 	WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
 	rtrsp->rt_readstate = newstate;
 
-	/* First, put new protection in place to avoid critical-section gap. */
+	/*
+	 * First, put new protection in place to avoid critical-section gap.
+	 * Disable preemption around the ATOM disables to ensure that
+	 * in_atomic() is true.
+	 */
 	if (statesnew & RCUTORTURE_RDR_BH)
 		local_bh_disable();
+	if (statesnew & RCUTORTURE_RDR_RBH)
+		rcu_read_lock_bh();
 	if (statesnew & RCUTORTURE_RDR_IRQ)
 		local_irq_disable();
 	if (statesnew & RCUTORTURE_RDR_PREEMPT)
 		preempt_disable();
-	if (statesnew & RCUTORTURE_RDR_RBH)
-		rcu_read_lock_bh();
 	if (statesnew & RCUTORTURE_RDR_SCHED)
 		rcu_read_lock_sched();
+	preempt_disable();
+	if (statesnew & RCUTORTURE_RDR_ATOM_BH)
+		local_bh_disable();
+	if (statesnew & RCUTORTURE_RDR_ATOM_RBH)
+		rcu_read_lock_bh();
+	preempt_enable();
 	if (statesnew & RCUTORTURE_RDR_RCU)
 		idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
 
-	/* Next, remove old protection, irq first due to bh conflict. */
+	/*
+	 * Next, remove old protection, in decreasing order of strength
+	 * to avoid unlock paths that aren't safe in the stronger
+	 * context.  Disable preemption around the ATOM enables in
+	 * case the context was only atomic due to IRQ disabling.
+	 */
+	preempt_disable();
 	if (statesold & RCUTORTURE_RDR_IRQ)
 		local_irq_enable();
-	if (statesold & RCUTORTURE_RDR_BH)
+	if (statesold & RCUTORTURE_RDR_ATOM_BH)
 		local_bh_enable();
+	if (statesold & RCUTORTURE_RDR_ATOM_RBH)
+		rcu_read_unlock_bh();
+	preempt_enable();
 	if (statesold & RCUTORTURE_RDR_PREEMPT)
 		preempt_enable();
-	if (statesold & RCUTORTURE_RDR_RBH)
-		rcu_read_unlock_bh();
 	if (statesold & RCUTORTURE_RDR_SCHED)
 		rcu_read_unlock_sched();
+	if (statesold & RCUTORTURE_RDR_BH)
+		local_bh_enable();
+	if (statesold & RCUTORTURE_RDR_RBH)
+		rcu_read_unlock_bh();
+
 	if (statesold & RCUTORTURE_RDR_RCU) {
 		bool lockit = !statesnew && !(torture_random(trsp) & 0xffff);
 
@@ -1313,6 +1338,12 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
 	int mask = rcutorture_extend_mask_max();
 	unsigned long randmask1 = torture_random(trsp) >> 8;
 	unsigned long randmask2 = randmask1 >> 3;
+	unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
+	unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
+	unsigned long nonatomic_bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+	unsigned long atomic_bhs = RCUTORTURE_RDR_ATOM_BH |
+				   RCUTORTURE_RDR_ATOM_RBH;
+	unsigned long tmp;
 
 	WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
 	/* Mostly only one bit (need preemption!), sometimes lots of bits. */
@@ -1320,11 +1351,49 @@ rcutorture_extend_mask(int oldmask, struct torture_random_state *trsp)
 		mask = mask & randmask2;
 	else
 		mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
-	/* Can't enable bh w/irq disabled. */
-	if ((mask & RCUTORTURE_RDR_IRQ) &&
-	    ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
-	     (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
-		mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+
+	/*
+	 * Can't enable bh w/irq disabled.
+	 */
+	tmp = atomic_bhs | nonatomic_bhs;
+	if (mask & RCUTORTURE_RDR_IRQ)
+		mask |= oldmask & tmp;
+
+	/*
+	 * Ideally these sequences would be detected in debug builds
+	 * (regardless of RT), but until then don't stop testing
+	 * them on non-RT.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		/*
+		 * Can't release the outermost rcu lock in an irq disabled
+		 * section without preemption also being disabled, if irqs
+		 * had ever been enabled during this RCU critical section
+		 * (could leak a special flag and delay reporting the qs).
+		 */
+		if ((oldmask & RCUTORTURE_RDR_RCU) &&
+		    (mask & RCUTORTURE_RDR_IRQ) &&
+		    !(mask & preempts))
+			mask |= RCUTORTURE_RDR_RCU;
+
+		/* Can't modify atomic bh in non-atomic context */
+		if ((oldmask & atomic_bhs) && (mask & atomic_bhs) &&
+		    !(mask & preempts_irq)) {
+			mask |= oldmask & preempts_irq;
+			if (mask & RCUTORTURE_RDR_IRQ)
+				mask |= oldmask & tmp;
+		}
+		if ((mask & atomic_bhs) && !(mask & preempts_irq))
+			mask |= RCUTORTURE_RDR_PREEMPT;
+
+		/* Can't modify non-atomic bh in atomic context */
+		tmp = nonatomic_bhs;
+		if (oldmask & preempts_irq)
+			mask &= ~tmp;
+		if ((oldmask | mask) & preempts_irq)
+			mask |= oldmask & tmp;
+	}
+
 	return mask ?: RCUTORTURE_RDR_RCU;
 }
 
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8ce77d9ac716c..1fa415198e8d8 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -113,8 +113,10 @@ static struct rcu_state rcu_state = {
 static bool dump_tree;
 module_param(dump_tree, bool, 0444);
 /* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
-static bool use_softirq = true;
+static bool use_softirq = !IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(use_softirq, bool, 0444);
+#endif
 /* Control rcu_node-tree auto-balancing at boot time. */
 static bool rcu_fanout_exact;
 module_param(rcu_fanout_exact, bool, 0444);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 982fc5be52698..4ce2fd80e28f0 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -289,10 +289,14 @@ void rcu_note_context_switch(bool preempt)
 	struct task_struct *t = current;
 	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 	struct rcu_node *rnp;
+	int sleeping_l = 0;
 
 	trace_rcu_utilization(TPS("Start context switch"));
 	lockdep_assert_irqs_disabled();
-	WARN_ON_ONCE(!preempt && rcu_preempt_depth() > 0);
+#if defined(CONFIG_PREEMPT_RT)
+	sleeping_l = t->sleeping_lock;
+#endif
+	WARN_ON_ONCE(!preempt && rcu_preempt_depth() > 0 && !sleeping_l);
 	if (rcu_preempt_depth() > 0 &&
 	    !t->rcu_read_unlock_special.b.blocked) {
 
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 2de49b5d8dd29..294f7021a4591 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -69,8 +69,10 @@
 #ifndef CONFIG_TINY_RCU
 module_param(rcu_expedited, int, 0);
 module_param(rcu_normal, int, 0);
-static int rcu_normal_after_boot;
+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(rcu_normal_after_boot, int, 0);
+#endif
 #endif /* #ifndef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d95dc3f46444..86e017ec2af5e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -63,7 +63,11 @@ const_debug unsigned int sysctl_sched_features =
  * Number of tasks to iterate in a single balance run.
  * Limited because this is done with IRQs disabled.
  */
+#ifdef CONFIG_PREEMPT_RT
+const_debug unsigned int sysctl_sched_nr_migrate = 8;
+#else
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
+#endif
 
 /*
  * period over which we measure -rt task CPU usage in us.
@@ -511,9 +515,15 @@ static bool set_nr_if_polling(struct task_struct *p)
 #endif
 #endif
 
-static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task,
+			 bool sleeper)
 {
-	struct wake_q_node *node = &task->wake_q;
+	struct wake_q_node *node;
+
+	if (sleeper)
+		node = &task->wake_q_sleeper;
+	else
+		node = &task->wake_q;
 
 	/*
 	 * Atomically grab the task, if ->wake_q is !nil already it means
@@ -549,7 +559,13 @@ static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
  */
 void wake_q_add(struct wake_q_head *head, struct task_struct *task)
 {
-	if (__wake_q_add(head, task))
+	if (__wake_q_add(head, task, false))
+		get_task_struct(task);
+}
+
+void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task)
+{
+	if (__wake_q_add(head, task, true))
 		get_task_struct(task);
 }
 
@@ -572,28 +588,39 @@ void wake_q_add(struct wake_q_head *head, struct task_struct *task)
  */
 void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
 {
-	if (!__wake_q_add(head, task))
+	if (!__wake_q_add(head, task, false))
 		put_task_struct(task);
 }
 
-void wake_up_q(struct wake_q_head *head)
+void __wake_up_q(struct wake_q_head *head, bool sleeper)
 {
 	struct wake_q_node *node = head->first;
 
 	while (node != WAKE_Q_TAIL) {
 		struct task_struct *task;
 
-		task = container_of(node, struct task_struct, wake_q);
+		if (sleeper)
+			task = container_of(node, struct task_struct, wake_q_sleeper);
+		else
+			task = container_of(node, struct task_struct, wake_q);
+
 		BUG_ON(!task);
 		/* Task can safely be re-inserted now: */
 		node = node->next;
-		task->wake_q.next = NULL;
 
+		if (sleeper)
+			task->wake_q_sleeper.next = NULL;
+		else
+			task->wake_q.next = NULL;
 		/*
 		 * wake_up_process() executes a full barrier, which pairs with
 		 * the queueing in wake_q_add() so as not to miss wakeups.
 		 */
-		wake_up_process(task);
+		if (sleeper)
+			wake_up_lock_sleeper(task);
+		else
+			wake_up_process(task);
+
 		put_task_struct(task);
 	}
 }
@@ -629,6 +656,48 @@ void resched_curr(struct rq *rq)
 		trace_sched_wake_idle_without_ipi(cpu);
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+
+static int tsk_is_polling(struct task_struct *p)
+{
+#ifdef TIF_POLLING_NRFLAG
+	return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
+#else
+	return 0;
+#endif
+}
+
+void resched_curr_lazy(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	int cpu;
+
+	if (!sched_feat(PREEMPT_LAZY)) {
+		resched_curr(rq);
+		return;
+	}
+
+	lockdep_assert_held(&rq->lock);
+
+	if (test_tsk_need_resched(curr))
+		return;
+
+	if (test_tsk_need_resched_lazy(curr))
+		return;
+
+	set_tsk_need_resched_lazy(curr);
+
+	cpu = cpu_of(rq);
+	if (cpu == smp_processor_id())
+		return;
+
+	/* NEED_RESCHED_LAZY must be visible before we test polling */
+	smp_mb();
+	if (!tsk_is_polling(curr))
+		smp_send_reschedule(cpu);
+}
+#endif
+
 void resched_cpu(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
@@ -1709,7 +1778,7 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
 	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
 		return false;
 
-	if (is_per_cpu_kthread(p))
+	if (is_per_cpu_kthread(p) || __migrate_disabled(p))
 		return cpu_online(cpu);
 
 	return cpu_active(cpu);
@@ -1756,6 +1825,7 @@ static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
 struct migration_arg {
 	struct task_struct *task;
 	int dest_cpu;
+	bool done;
 };
 
 /*
@@ -1791,6 +1861,11 @@ static int migration_cpu_stop(void *data)
 	struct task_struct *p = arg->task;
 	struct rq *rq = this_rq();
 	struct rq_flags rf;
+	int dest_cpu = arg->dest_cpu;
+
+	/* We don't look at arg after this point. */
+	smp_mb();
+	arg->done = true;
 
 	/*
 	 * The original target CPU might have gone down and we might
@@ -1813,9 +1888,9 @@ static int migration_cpu_stop(void *data)
 	 */
 	if (task_rq(p) == rq) {
 		if (task_on_rq_queued(p))
-			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
+			rq = __migrate_task(rq, &rf, p, dest_cpu);
 		else
-			p->wake_cpu = arg->dest_cpu;
+			p->wake_cpu = dest_cpu;
 	}
 	rq_unlock(rq, &rf);
 	raw_spin_unlock(&p->pi_lock);
@@ -1831,9 +1906,18 @@ static int migration_cpu_stop(void *data)
 void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
 {
 	cpumask_copy(&p->cpus_mask, new_mask);
-	p->nr_cpus_allowed = cpumask_weight(new_mask);
+	if (p->cpus_ptr == &p->cpus_mask)
+		p->nr_cpus_allowed = cpumask_weight(new_mask);
 }
 
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+int __migrate_disabled(struct task_struct *p)
+{
+	return p->migrate_disable;
+}
+EXPORT_SYMBOL_GPL(__migrate_disabled);
+#endif
+
 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
 {
 	struct rq *rq = task_rq(p);
@@ -1927,7 +2011,8 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 	}
 
 	/* 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) ||
+	    p->cpus_ptr != &p->cpus_mask)
 		goto out;
 
 	if (task_running(rq, p) || p->state == TASK_WAKING) {
@@ -2124,6 +2209,18 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p,
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static bool check_task_state(struct task_struct *p, long match_state)
+{
+	bool match = false;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	if (p->state == match_state || p->saved_state == match_state)
+		match = true;
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	return match;
+}
+
 /*
  * wait_task_inactive - wait for a thread to unschedule.
  *
@@ -2168,7 +2265,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
 		 * is actually now running somewhere else!
 		 */
 		while (task_running(rq, p)) {
-			if (match_state && unlikely(p->state != match_state))
+			if (match_state && !check_task_state(p, match_state))
 				return 0;
 			cpu_relax();
 		}
@@ -2183,7 +2280,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
 		running = task_running(rq, p);
 		queued = task_on_rq_queued(p);
 		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, &rf);
 
@@ -2828,7 +2926,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
 	int cpu, success = 0;
 
 	preempt_disable();
-	if (p == current) {
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT) && p == current) {
 		/*
 		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
 		 * == smp_processor_id()'. Together this means we can special
@@ -2858,8 +2956,26 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
 	 */
 	raw_spin_lock_irqsave(&p->pi_lock, flags);
 	smp_mb__after_spinlock();
-	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 unlock;
+	}
+	/*
+	 * 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;
 
 	trace_sched_waking(p);
 
@@ -3049,6 +3165,18 @@ int wake_up_process(struct task_struct *p)
 }
 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_UNINTERRUPTIBLE, WF_LOCK_SLEEPER);
+}
+
 int wake_up_state(struct task_struct *p, unsigned int state)
 {
 	return try_to_wake_up(p, state, 0);
@@ -3295,6 +3423,9 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
 	p->on_cpu = 0;
 #endif
 	init_task_preempt_count(p);
+#ifdef CONFIG_HAVE_PREEMPT_LAZY
+	task_thread_info(p)->preempt_lazy_count = 0;
+#endif
 #ifdef CONFIG_SMP
 	plist_node_init(&p->pushable_tasks, MAX_PRIO);
 	RB_CLEAR_NODE(&p->pushable_dl_tasks);
@@ -3631,23 +3762,18 @@ static struct rq *finish_task_switch(struct task_struct *prev)
 	 *   provided by mmdrop(),
 	 * - a sync_core for SYNC_CORE.
 	 */
+	/*
+	 * We use mmdrop_delayed() here so we don't have to do the
+	 * full __mmdrop() when we are the last user.
+	 */
 	if (mm) {
 		membarrier_mm_sync_core_before_usermode(mm);
-		mmdrop(mm);
+		mmdrop_delayed(mm);
 	}
 	if (unlikely(prev_state == TASK_DEAD)) {
 		if (prev->sched_class->task_dead)
 			prev->sched_class->task_dead(prev);
 
-		/*
-		 * Remove function-return probe instances associated with this
-		 * task and put them back on the free list.
-		 */
-		kprobe_flush_task(prev);
-
-		/* Task is done with its stack. */
-		put_task_stack(prev);
-
 		put_task_struct_rcu_user(prev);
 	}
 
@@ -4367,6 +4493,8 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
 	BUG();
 }
 
+static void migrate_disabled_sched(struct task_struct *p);
+
 /*
  * __schedule() is the main scheduler function.
  *
@@ -4445,6 +4573,9 @@ static void __sched notrace __schedule(bool preempt)
 	rq_lock(rq, &rf);
 	smp_mb__after_spinlock();
 
+	if (__migrate_disabled(prev))
+		migrate_disabled_sched(prev);
+
 	/* Promote REQ to ACT */
 	rq->clock_update_flags <<= 1;
 	update_rq_clock(rq);
@@ -4494,6 +4625,7 @@ static void __sched notrace __schedule(bool preempt)
 
 	next = pick_next_task(rq, prev, &rf);
 	clear_tsk_need_resched(prev);
+	clear_tsk_need_resched_lazy(prev);
 	clear_preempt_need_resched();
 
 	if (likely(prev != next)) {
@@ -4691,6 +4823,30 @@ static void __sched notrace preempt_schedule_common(void)
 	} while (need_resched());
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+/*
+ * If TIF_NEED_RESCHED is then we allow to be scheduled away since this is
+ * set by a RT task. Oterwise we try to avoid beeing scheduled out as long as
+ * preempt_lazy_count counter >0.
+ */
+static __always_inline int preemptible_lazy(void)
+{
+	if (test_thread_flag(TIF_NEED_RESCHED))
+		return 1;
+	if (current_thread_info()->preempt_lazy_count)
+		return 0;
+	return 1;
+}
+
+#else
+
+static inline int preemptible_lazy(void)
+{
+	return 1;
+}
+
+#endif
+
 #ifdef CONFIG_PREEMPTION
 /*
  * This is the entry point to schedule() from in-kernel preemption
@@ -4704,7 +4860,8 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
 	 */
 	if (likely(!preemptible()))
 		return;
-
+	if (!preemptible_lazy())
+		return;
 	preempt_schedule_common();
 }
 NOKPROBE_SYMBOL(preempt_schedule);
@@ -4731,6 +4888,9 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
 	if (likely(!preemptible()))
 		return;
 
+	if (!preemptible_lazy())
+		return;
+
 	do {
 		/*
 		 * Because the function tracer can trace preempt_count_sub()
@@ -6565,7 +6725,9 @@ void init_idle(struct task_struct *idle, int cpu)
 
 	/* Set the preempt count _outside_ the spinlocks! */
 	init_idle_preempt_count(idle, cpu);
-
+#ifdef CONFIG_HAVE_PREEMPT_LAZY
+	task_thread_info(idle)->preempt_lazy_count = 0;
+#endif
 	/*
 	 * The idle tasks have their own, simple scheduling class:
 	 */
@@ -6670,6 +6832,7 @@ void sched_setnuma(struct task_struct *p, int nid)
 #endif /* CONFIG_NUMA_BALANCING */
 
 #ifdef CONFIG_HOTPLUG_CPU
+
 /*
  * Ensure that the idle task is using init_mm right before its CPU goes
  * offline.
@@ -6764,6 +6927,7 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
 			break;
 
 		next = __pick_migrate_task(rq);
+		WARN_ON_ONCE(__migrate_disabled(next));
 
 		/*
 		 * Rules for changing task_struct::cpus_mask are holding
@@ -7231,7 +7395,7 @@ void __init sched_init(void)
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 static inline int preempt_count_equals(int preempt_offset)
 {
-	int nested = preempt_count() + rcu_preempt_depth();
+	int nested = preempt_count() + sched_rcu_preempt_depth();
 
 	return (nested == preempt_offset);
 }
@@ -8482,3 +8646,172 @@ void call_trace_sched_update_nr_running(struct rq *rq, int count)
 {
         trace_sched_update_nr_running_tp(rq, count);
 }
+
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+static inline void
+update_nr_migratory(struct task_struct *p, long delta)
+{
+	if (unlikely((p->sched_class == &rt_sched_class ||
+		      p->sched_class == &dl_sched_class) &&
+		      p->nr_cpus_allowed > 1)) {
+		if (p->sched_class == &rt_sched_class)
+			task_rq(p)->rt.rt_nr_migratory += delta;
+		else
+			task_rq(p)->dl.dl_nr_migratory += delta;
+	}
+}
+
+static inline void
+migrate_disable_update_cpus_allowed(struct task_struct *p)
+{
+	p->cpus_ptr = cpumask_of(smp_processor_id());
+	update_nr_migratory(p, -1);
+	p->nr_cpus_allowed = 1;
+}
+
+static inline void
+migrate_enable_update_cpus_allowed(struct task_struct *p)
+{
+	struct rq *rq;
+	struct rq_flags rf;
+
+	rq = task_rq_lock(p, &rf);
+	p->cpus_ptr = &p->cpus_mask;
+	p->nr_cpus_allowed = cpumask_weight(&p->cpus_mask);
+	update_nr_migratory(p, 1);
+	task_rq_unlock(rq, p, &rf);
+}
+
+void migrate_disable(void)
+{
+	preempt_disable();
+
+	if (++current->migrate_disable == 1) {
+		this_rq()->nr_pinned++;
+		preempt_lazy_disable();
+#ifdef CONFIG_SCHED_DEBUG
+		WARN_ON_ONCE(current->pinned_on_cpu >= 0);
+		current->pinned_on_cpu = smp_processor_id();
+#endif
+	}
+
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_disable);
+
+static void migrate_disabled_sched(struct task_struct *p)
+{
+	if (p->migrate_disable_scheduled)
+		return;
+
+	migrate_disable_update_cpus_allowed(p);
+	p->migrate_disable_scheduled = 1;
+}
+
+static DEFINE_PER_CPU(struct cpu_stop_work, migrate_work);
+static DEFINE_PER_CPU(struct migration_arg, migrate_arg);
+
+void migrate_enable(void)
+{
+	struct task_struct *p = current;
+	struct rq *rq = this_rq();
+	int cpu = task_cpu(p);
+
+	WARN_ON_ONCE(p->migrate_disable <= 0);
+	if (p->migrate_disable > 1) {
+		p->migrate_disable--;
+		return;
+	}
+
+	preempt_disable();
+
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(current->pinned_on_cpu != cpu);
+	current->pinned_on_cpu = -1;
+#endif
+
+	WARN_ON_ONCE(rq->nr_pinned < 1);
+
+	p->migrate_disable = 0;
+	rq->nr_pinned--;
+#ifdef CONFIG_HOTPLUG_CPU
+	if (rq->nr_pinned == 0 && unlikely(!cpu_active(cpu)) &&
+	    takedown_cpu_task)
+		wake_up_process(takedown_cpu_task);
+#endif
+
+	if (!p->migrate_disable_scheduled)
+		goto out;
+
+	p->migrate_disable_scheduled = 0;
+
+	migrate_enable_update_cpus_allowed(p);
+
+	WARN_ON(smp_processor_id() != cpu);
+	if (!is_cpu_allowed(p, cpu)) {
+		struct migration_arg __percpu *arg;
+		struct cpu_stop_work __percpu *work;
+		struct rq_flags rf;
+
+		work = this_cpu_ptr(&migrate_work);
+		arg = this_cpu_ptr(&migrate_arg);
+		WARN_ON_ONCE(!arg->done && !work->disabled && work->arg);
+
+		arg->task = p;
+		arg->done = false;
+
+		rq = task_rq_lock(p, &rf);
+		update_rq_clock(rq);
+		arg->dest_cpu = select_fallback_rq(cpu, p);
+		task_rq_unlock(rq, p, &rf);
+
+		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
+				    arg, work);
+	}
+
+out:
+	preempt_lazy_enable();
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_enable);
+
+int cpu_nr_pinned(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	return rq->nr_pinned;
+}
+
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+static void migrate_disabled_sched(struct task_struct *p)
+{
+}
+
+void migrate_disable(void)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	current->migrate_disable++;
+#endif
+	barrier();
+}
+EXPORT_SYMBOL(migrate_disable);
+
+void migrate_enable(void)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	struct task_struct *p = current;
+
+	WARN_ON_ONCE(p->migrate_disable <= 0);
+	p->migrate_disable--;
+#endif
+	barrier();
+}
+EXPORT_SYMBOL(migrate_enable);
+
+#else
+static void migrate_disabled_sched(struct task_struct *p)
+{
+}
+
+#endif
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 36c54265bb2b0..31dc08cd5b46a 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -958,6 +958,10 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
 		P(dl.runtime);
 		P(dl.deadline);
 	}
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+	P(migrate_disable);
+#endif
+	P(nr_cpus_allowed);
 #undef PN_SCHEDSTAT
 #undef P_SCHEDSTAT
 
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1a68a0536adda..d31aab136644c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4357,7 +4357,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 	ideal_runtime = sched_slice(cfs_rq, curr);
 	delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
 	if (delta_exec > ideal_runtime) {
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 		/*
 		 * The current task ran long enough, ensure it doesn't get
 		 * re-elected due to buddy favours.
@@ -4381,7 +4381,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 		return;
 
 	if (delta > ideal_runtime)
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 }
 
 static void
@@ -4524,7 +4524,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 	 * validating it and just reschedule.
 	 */
 	if (queued) {
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 		return;
 	}
 	/*
@@ -4661,7 +4661,7 @@ static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
 	 * hierarchy can be throttled
 	 */
 	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 }
 
 static __always_inline
@@ -5396,7 +5396,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
 
 		if (delta < 0) {
 			if (rq->curr == p)
-				resched_curr(rq);
+				resched_curr_lazy(rq);
 			return;
 		}
 		hrtick_start(rq, delta);
@@ -6953,7 +6953,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 	return;
 
 preempt:
-	resched_curr(rq);
+	resched_curr_lazy(rq);
 	/*
 	 * Only set the backward buddy when the current task is still
 	 * on the rq. This can happen when a wakeup gets interleaved
@@ -10694,7 +10694,7 @@ static void task_fork_fair(struct task_struct *p)
 		 * 'current' within the tree based on its new key value.
 		 */
 		swap(curr->vruntime, se->vruntime);
-		resched_curr(rq);
+		resched_curr_lazy(rq);
 	}
 
 	se->vruntime -= cfs_rq->min_vruntime;
@@ -10721,7 +10721,7 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
 	 */
 	if (rq->curr == p) {
 		if (p->prio > oldprio)
-			resched_curr(rq);
+			resched_curr_lazy(rq);
 	} else
 		check_preempt_curr(rq, p, 0);
 }
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 7481cd96f3915..862e8b3c7d280 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -45,11 +45,19 @@ SCHED_FEAT(DOUBLE_TICK, false)
  */
 SCHED_FEAT(NONTASK_CAPACITY, true)
 
+#ifdef CONFIG_PREEMPT_RT
+SCHED_FEAT(TTWU_QUEUE, false)
+# ifdef CONFIG_PREEMPT_LAZY
+SCHED_FEAT(PREEMPT_LAZY, true)
+# endif
+#else
+
 /*
  * Queue remote wakeups on the target CPU and process them
  * using the scheduler IPI. Reduces rq->lock contention/bounces.
  */
 SCHED_FEAT(TTWU_QUEUE, true)
+#endif
 
 /*
  * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 28709f6b0975c..21875239f06d7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1048,6 +1048,10 @@ struct rq {
 	/* Must be inspected within a rcu lock section */
 	struct cpuidle_state	*idle_state;
 #endif
+
+#if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP)
+	int			nr_pinned;
+#endif
 };
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
@@ -1714,6 +1718,7 @@ static inline int task_on_rq_migrating(struct task_struct *p)
 #define WF_FORK			0x02		/* Child wakeup after fork */
 #define WF_MIGRATED		0x04		/* Internal use, task got migrated */
 #define WF_ON_CPU		0x08		/* Wakee is on_cpu */
+#define WF_LOCK_SLEEPER		0x10		/* Wakeup spinlock "sleeper" */
 
 /*
  * To aid in avoiding the subversion of "niceness" due to uneven distribution
@@ -1932,6 +1937,15 @@ extern void reweight_task(struct task_struct *p, int prio);
 extern void resched_curr(struct rq *rq);
 extern void resched_cpu(int cpu);
 
+#ifdef CONFIG_PREEMPT_LAZY
+extern void resched_curr_lazy(struct rq *rq);
+#else
+static inline void resched_curr_lazy(struct rq *rq)
+{
+	resched_curr(rq);
+}
+#endif
+
 extern struct rt_bandwidth def_rt_bandwidth;
 extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
 
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index e1c655f928c74..f230b1ac7f910 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -64,6 +64,7 @@ void swake_up_all(struct swait_queue_head *q)
 	struct swait_queue *curr;
 	LIST_HEAD(tmp);
 
+	WARN_ON(irqs_disabled());
 	raw_spin_lock_irq(&q->lock);
 	list_splice_init(&q->task_list, &tmp);
 	while (!list_empty(&tmp)) {
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 1bd7e3af904f6..04ead8eeb07c6 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -500,6 +500,7 @@ static int init_rootdomain(struct root_domain *rd)
 	rd->rto_cpu = -1;
 	raw_spin_lock_init(&rd->rto_lock);
 	init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
+	atomic_or(IRQ_WORK_HARD_IRQ, &rd->rto_push_work.flags);
 #endif
 
 	init_dl_bw(&rd->dl_bw);
diff --git a/kernel/signal.c b/kernel/signal.c
index a38b3edc68511..c3d7abd1f6aea 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -20,6 +20,7 @@
 #include <linux/sched/task.h>
 #include <linux/sched/task_stack.h>
 #include <linux/sched/cputime.h>
+#include <linux/sched/rt.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/proc_fs.h>
@@ -403,13 +404,30 @@ void task_join_group_stop(struct task_struct *task)
 	}
 }
 
+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;
+}
+
 /*
  * 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;
@@ -431,7 +449,10 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
 	rcu_read_unlock();
 
 	if (override_rlimit || likely(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);
 	}
@@ -448,6 +469,13 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
 	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)
@@ -457,6 +485,21 @@ static void __sigqueue_free(struct sigqueue *q)
 	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)) {
+		if (atomic_dec_and_test(&up->sigpending))
+			free_uid(up);
+	} else
+		  __sigqueue_free(q);
+}
+
 void flush_sigqueue(struct sigpending *queue)
 {
 	struct sigqueue *q;
@@ -469,6 +512,21 @@ void flush_sigqueue(struct sigpending *queue)
 	}
 }
 
+/*
+ * 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 this kthread.
  */
@@ -593,7 +651,7 @@ static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *i
 			(info->si_code == SI_TIMER) &&
 			(info->si_sys_private);
 
-		__sigqueue_free(first);
+		sigqueue_free_current(first);
 	} else {
 		/*
 		 * Ok, it wasn't in the queue.  This must be
@@ -630,6 +688,8 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *in
 	bool resched_timer = false;
 	int signr;
 
+	WARN_ON_ONCE(tsk != current);
+
 	/* We only dequeue private signals from ourselves, we don't let
 	 * signalfd steal them
 	 */
@@ -1313,6 +1373,34 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
 	struct k_sigaction *action;
 	int sig = info->si_signo;
 
+	/*
+	 * 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()) {
+		struct task_struct *t = current;
+
+		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 = info->si_signo;
+			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
 	spin_lock_irqsave(&t->sighand->siglock, flags);
 	action = &t->sighand->action[sig-1];
 	ignored = action->sa.sa_handler == SIG_IGN;
@@ -1806,7 +1894,8 @@ 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;
@@ -2202,16 +2291,8 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 		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);
 		cgroup_enter_frozen();
-		preempt_enable_no_resched();
 		freezable_schedule();
 		cgroup_leave_frozen(true);
 	} else {
diff --git a/kernel/softirq.c b/kernel/softirq.c
index bf88d7f624332..5cbadfe313c39 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -25,6 +25,9 @@
 #include <linux/smpboot.h>
 #include <linux/tick.h>
 #include <linux/irq.h>
+#ifdef CONFIG_PREEMPT_RT
+#include <linux/local_lock.h>
+#endif
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>
@@ -92,6 +95,15 @@ static bool ksoftirqd_running(unsigned long pending)
 		!__kthread_should_park(tsk);
 }
 
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+DEFINE_PER_CPU(int, hardirqs_enabled);
+DEFINE_PER_CPU(int, hardirq_context);
+EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
+EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
+
+#endif
+
 /*
  * preempt_count and SOFTIRQ_OFFSET usage:
  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
@@ -101,6 +113,111 @@ static bool ksoftirqd_running(unsigned long pending)
  * This lets us distinguish between whether we are currently processing
  * softirq and whether we just have bh disabled.
  */
+#ifdef CONFIG_PREEMPT_RT
+
+struct bh_lock {
+	local_lock_t l;
+};
+
+static DEFINE_PER_CPU(struct bh_lock, bh_lock) = {
+	.l      = INIT_LOCAL_LOCK(l),
+};
+
+static DEFINE_PER_CPU(long, softirq_counter);
+
+void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+{
+	unsigned long __maybe_unused flags;
+	long soft_cnt;
+
+	WARN_ON_ONCE(in_irq());
+	if (!in_atomic()) {
+		local_lock(&bh_lock.l);
+		rcu_read_lock();
+	}
+	soft_cnt = this_cpu_inc_return(softirq_counter);
+	WARN_ON_ONCE(soft_cnt == 0);
+	current->softirq_count += SOFTIRQ_DISABLE_OFFSET;
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+	local_irq_save(flags);
+	if (soft_cnt == 1)
+		lockdep_softirqs_off(ip);
+	local_irq_restore(flags);
+#endif
+}
+EXPORT_SYMBOL(__local_bh_disable_ip);
+
+static void local_bh_disable_rt(void)
+{
+	local_bh_disable();
+}
+
+void _local_bh_enable(void)
+{
+	unsigned long __maybe_unused flags;
+	long soft_cnt;
+
+	soft_cnt = this_cpu_dec_return(softirq_counter);
+	WARN_ON_ONCE(soft_cnt < 0);
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+	local_irq_save(flags);
+	if (soft_cnt == 0)
+		lockdep_softirqs_on(_RET_IP_);
+	local_irq_restore(flags);
+#endif
+
+	current->softirq_count -= SOFTIRQ_DISABLE_OFFSET;
+	if (!in_atomic()) {
+		rcu_read_unlock();
+		local_unlock(&bh_lock.l);
+	}
+}
+
+void _local_bh_enable_rt(void)
+{
+	_local_bh_enable();
+}
+
+void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+{
+	u32 pending;
+	long count;
+
+	WARN_ON_ONCE(in_irq());
+	lockdep_assert_irqs_enabled();
+
+	local_irq_disable();
+	count = this_cpu_read(softirq_counter);
+
+	if (unlikely(count == 1)) {
+		pending = local_softirq_pending();
+		if (pending && !ksoftirqd_running(pending)) {
+			if (!in_atomic())
+				__do_softirq();
+			else
+				wakeup_softirqd();
+		}
+		lockdep_softirqs_on(ip);
+	}
+	count = this_cpu_dec_return(softirq_counter);
+	WARN_ON_ONCE(count < 0);
+	local_irq_enable();
+
+	if (!in_atomic()) {
+		rcu_read_unlock();
+		local_unlock(&bh_lock.l);
+	}
+
+	current->softirq_count -= SOFTIRQ_DISABLE_OFFSET;
+	preempt_check_resched();
+}
+EXPORT_SYMBOL(__local_bh_enable_ip);
+
+#else
+static void local_bh_disable_rt(void) { }
+static void _local_bh_enable_rt(void) { }
 
 /*
  * This one is for softirq.c-internal use,
@@ -108,11 +225,6 @@ static bool ksoftirqd_running(unsigned long pending)
  */
 #ifdef CONFIG_TRACE_IRQFLAGS
 
-DEFINE_PER_CPU(int, hardirqs_enabled);
-DEFINE_PER_CPU(int, hardirq_context);
-EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
-EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
-
 void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
 {
 	unsigned long flags;
@@ -202,6 +314,7 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
 	preempt_check_resched();
 }
 EXPORT_SYMBOL(__local_bh_enable_ip);
+#endif
 
 /*
  * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
@@ -272,7 +385,11 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 	pending = local_softirq_pending();
 	account_irq_enter_time(current);
 
+#ifdef CONFIG_PREEMPT_RT
+	current->softirq_count |= SOFTIRQ_OFFSET;
+#else
 	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+#endif
 	in_hardirq = lockdep_softirq_start();
 
 restart:
@@ -306,9 +423,10 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 		h++;
 		pending >>= softirq_bit;
 	}
-
+#ifndef CONFIG_PREEMPT_RT
 	if (__this_cpu_read(ksoftirqd) == current)
 		rcu_softirq_qs();
+#endif
 	local_irq_disable();
 
 	pending = local_softirq_pending();
@@ -322,11 +440,16 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 
 	lockdep_softirq_end(in_hardirq);
 	account_irq_exit_time(current);
+#ifdef CONFIG_PREEMPT_RT
+	current->softirq_count &= ~SOFTIRQ_OFFSET;
+#else
 	__local_bh_enable(SOFTIRQ_OFFSET);
+#endif
 	WARN_ON_ONCE(in_interrupt());
 	current_restore_flags(old_flags, PF_MEMALLOC);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 asmlinkage __visible void do_softirq(void)
 {
 	__u32 pending;
@@ -344,6 +467,7 @@ asmlinkage __visible void do_softirq(void)
 
 	local_irq_restore(flags);
 }
+#endif
 
 /**
  * irq_enter_rcu - Enter an interrupt context with RCU watching
@@ -371,6 +495,16 @@ void irq_enter(void)
 	irq_enter_rcu();
 }
 
+#ifdef CONFIG_PREEMPT_RT
+
+static inline void invoke_softirq(void)
+{
+	if (this_cpu_read(softirq_counter) == 0)
+		wakeup_softirqd();
+}
+
+#else
+
 static inline void invoke_softirq(void)
 {
 	if (ksoftirqd_running(local_softirq_pending()))
@@ -396,6 +530,7 @@ static inline void invoke_softirq(void)
 		wakeup_softirqd();
 	}
 }
+#endif
 
 static inline void tick_irq_exit(void)
 {
@@ -453,6 +588,27 @@ void irq_exit(void)
 /*
  * This function must run with irqs disabled!
  */
+#ifdef CONFIG_PREEMPT_RT
+void raise_softirq_irqoff(unsigned int nr)
+{
+	__raise_softirq_irqoff(nr);
+
+	/*
+	 * If we're in an hard interrupt we let irq return code deal
+	 * with the wakeup of ksoftirqd.
+	 */
+	if (in_irq())
+		return;
+	/*
+	 * If were are not in BH-disabled section then we have to wake
+	 * ksoftirqd.
+	 */
+	if (this_cpu_read(softirq_counter) == 0)
+		wakeup_softirqd();
+}
+
+#else
+
 inline void raise_softirq_irqoff(unsigned int nr)
 {
 	__raise_softirq_irqoff(nr);
@@ -470,6 +626,8 @@ inline void raise_softirq_irqoff(unsigned int nr)
 		wakeup_softirqd();
 }
 
+#endif
+
 void raise_softirq(unsigned int nr)
 {
 	unsigned long flags;
@@ -613,7 +771,8 @@ void tasklet_kill(struct tasklet_struct *t)
 
 	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
 		do {
-			yield();
+			local_bh_disable();
+			local_bh_enable();
 		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
 	}
 	tasklet_unlock_wait(t);
@@ -643,6 +802,7 @@ static int ksoftirqd_should_run(unsigned int cpu)
 
 static void run_ksoftirqd(unsigned int cpu)
 {
+	local_bh_disable_rt();
 	local_irq_disable();
 	if (local_softirq_pending()) {
 		/*
@@ -651,10 +811,12 @@ static void run_ksoftirqd(unsigned int cpu)
 		 */
 		__do_softirq();
 		local_irq_enable();
+		_local_bh_enable_rt();
 		cond_resched();
 		return;
 	}
 	local_irq_enable();
+	_local_bh_enable_rt();
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
@@ -728,6 +890,13 @@ static struct smp_hotplug_thread softirq_threads = {
 
 static __init int spawn_ksoftirqd(void)
 {
+#ifdef CONFIG_PREEMPT_RT
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		lockdep_set_novalidate_class(per_cpu_ptr(&bh_lock.l.lock, cpu));
+#endif
+
 	cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
 				  takeover_tasklets);
 	BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
@@ -736,6 +905,75 @@ static __init int spawn_ksoftirqd(void)
 }
 early_initcall(spawn_ksoftirqd);
 
+#ifdef CONFIG_PREEMPT_RT
+
+/*
+ * On preempt-rt a softirq running context 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)
+{
+	struct task_struct *tsk = __this_cpu_read(ksoftirqd);
+	static int rate_limit;
+	bool okay = false;
+	u32 warnpending;
+
+	if (rate_limit >= 10)
+		return;
+
+	warnpending = local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK;
+	if (!warnpending)
+		return;
+
+	if (!tsk)
+		return;
+	/*
+	 * If ksoftirqd is blocked on a lock then we may go idle with pending
+	 * softirq.
+	 */
+	raw_spin_lock(&tsk->pi_lock);
+	if (tsk->pi_blocked_on || tsk->state == TASK_RUNNING ||
+	    (tsk->state == TASK_UNINTERRUPTIBLE && tsk->sleeping_lock)) {
+		okay = true;
+	}
+	raw_spin_unlock(&tsk->pi_lock);
+	if (okay)
+		return;
+	/*
+	 * The softirq lock is held in non-atomic context and the owner is
+	 * blocking on a lock. It will schedule softirqs once the counter goes
+	 * back to zero.
+	 */
+	if (this_cpu_read(softirq_counter) > 0)
+		return;
+
+	printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+	       warnpending);
+	rate_limit++;
+}
+
+#else
+
+void softirq_check_pending_idle(void)
+{
+	static int ratelimit;
+
+	if (ratelimit < 10 &&
+	    (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
+		pr_warn("NOHZ: local_softirq_pending %02x\n",
+			(unsigned int) local_softirq_pending());
+		ratelimit++;
+	}
+}
+
+#endif
+
 /*
  * [ These __weak aliases are kept in a separate compilation unit, so that
  *   GCC does not inline them incorrectly. ]
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 865bb0228ab66..933816b2fb8f8 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -86,8 +86,11 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
 	enabled = stopper->enabled;
 	if (enabled)
 		__cpu_stop_queue_work(stopper, work, &wakeq);
-	else if (work->done)
-		cpu_stop_signal_done(work->done);
+	else {
+		work->disabled = true;
+		if (work->done)
+			cpu_stop_signal_done(work->done);
+	}
 	raw_spin_unlock_irqrestore(&stopper->lock, flags);
 
 	wake_up_q(&wakeq);
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 95b6a708b0406..0b2da8da0c48e 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1828,7 +1828,7 @@ static void __hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
 	 * expiry.
 	 */
 	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
-		if (task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT))
+		if ((task_is_realtime(current) && !(mode & HRTIMER_MODE_SOFT)) || system_state != SYSTEM_RUNNING)
 			mode |= HRTIMER_MODE_HARD;
 	}
 
@@ -1993,6 +1993,38 @@ SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp,
 }
 #endif
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * Sleep for 1 ms in hope whoever holds what we want will let it go.
+ */
+void cpu_chill(void)
+{
+	unsigned int freeze_flag = current->flags & PF_NOFREEZE;
+	struct task_struct *self = current;
+	ktime_t chill_time;
+
+	raw_spin_lock_irq(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+	raw_spin_unlock_irq(&self->pi_lock);
+
+	chill_time = ktime_set(0, NSEC_PER_MSEC);
+
+	current->flags |= PF_NOFREEZE;
+	sleeping_lock_inc();
+	schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD);
+	sleeping_lock_dec();
+	if (!freeze_flag)
+		current->flags &= ~PF_NOFREEZE;
+
+	raw_spin_lock_irq(&self->pi_lock);
+	__set_current_state_no_track(self->saved_state);
+	self->saved_state = TASK_RUNNING;
+	raw_spin_unlock_irq(&self->pi_lock);
+}
+EXPORT_SYMBOL(cpu_chill);
+#endif
+
 /*
  * Functions related to boot-time initialization:
  */
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index f0199a4ba1add..d5dfd51f03ee8 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -923,14 +923,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
 		return false;
 
 	if (unlikely(local_softirq_pending())) {
-		static int ratelimit;
-
-		if (ratelimit < 10 &&
-		    (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
-			pr_warn("NOHZ: local_softirq_pending %02x\n",
-				(unsigned int) local_softirq_pending());
-			ratelimit++;
-		}
+		softirq_check_pending_idle();
 		return false;
 	}
 
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index a50364df10543..e25cb9d7f09a1 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1765,6 +1765,8 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)
 {
 	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
 
+	irq_work_tick_soft();
+
 	__run_timers(base);
 	if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
 		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f40d850ebabcc..6e74b066a0a4d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2444,6 +2444,7 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned short type,
 	struct task_struct *tsk = current;
 
 	entry->preempt_count		= pc & 0xff;
+	entry->preempt_lazy_count	= preempt_lazy_count();
 	entry->pid			= (tsk) ? tsk->pid : 0;
 	entry->type			= type;
 	entry->flags =
@@ -2455,8 +2456,11 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned short type,
 		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
 		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
 		((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
-		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
+		(tif_need_resched_now() ? TRACE_FLAG_NEED_RESCHED : 0) |
+		(need_resched_lazy() ? TRACE_FLAG_NEED_RESCHED_LAZY : 0) |
 		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
+
+	entry->migrate_disable = (tsk) ? __migrate_disabled(tsk) & 0xFF : 0;
 }
 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
 
@@ -3785,11 +3789,13 @@ static void print_lat_help_header(struct seq_file *m)
 	seq_puts(m, "#                  _------=> CPU#            \n"
 		    "#                 / _-----=> irqs-off        \n"
 		    "#                | / _----=> need-resched    \n"
-		    "#                || / _---=> hardirq/softirq \n"
-		    "#                ||| / _--=> preempt-depth   \n"
-		    "#                |||| /     delay            \n"
-		    "#  cmd     pid   ||||| time  |   caller      \n"
-		    "#     \\   /      |||||  \\    |   /         \n");
+		    "#                || / _----=> need-resched_lazy\n"
+		    "#                ||| / _---=> hardirq/softirq \n"
+		    "#                |||| / _--=> preempt-depth   \n"
+		    "#                ||||| / _-=> migrate-disable \n"
+		    "#                |||||| /     delay           \n"
+		    "#  cmd     pid   ||||||| time  |   caller     \n"
+		    "#     \\   /      ||||||   \\   |   /        \n");
 }
 
 static void print_event_info(struct array_buffer *buf, struct seq_file *m)
@@ -3825,11 +3831,12 @@ static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file
 
 	seq_printf(m, "#                          %.*s  _-----=> irqs-off\n", prec, space);
 	seq_printf(m, "#                          %.*s / _----=> need-resched\n", prec, space);
-	seq_printf(m, "#                          %.*s| / _---=> hardirq/softirq\n", prec, space);
-	seq_printf(m, "#                          %.*s|| / _--=> preempt-depth\n", prec, space);
-	seq_printf(m, "#                          %.*s||| /     delay\n", prec, space);
-	seq_printf(m, "#           TASK-PID %.*sCPU#  ||||    TIMESTAMP  FUNCTION\n", prec, "   TGID   ");
-	seq_printf(m, "#              | |   %.*s  |   ||||       |         |\n", prec, "     |    ");
+	seq_printf(m, "#                          %.*s| / _----=> need-resched\n", prec, space);
+	seq_printf(m, "#                          %.*s|| / _---=> hardirq/softirq\n", prec, space);
+	seq_printf(m, "#                          %.*s||| / _--=> preempt-depth\n", prec, space);
+	seq_printf(m, "#                          %.*s||||/     delay\n", prec, space);
+	seq_printf(m, "#           TASK-PID %.*sCPU#  |||||   TIMESTAMP  FUNCTION\n", prec, "   TGID   ");
+	seq_printf(m, "#              | |   %.*s  |   |||||      |         |\n", prec, "     |    ");
 }
 
 void
@@ -9247,7 +9254,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
 	tracing_off();
 
 	local_irq_save(flags);
-	printk_nmi_direct_enter();
 
 	/* Simulate the iterator */
 	trace_init_global_iter(&iter);
@@ -9327,7 +9333,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
 		atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
 	}
 	atomic_dec(&dump_running);
-	printk_nmi_direct_exit();
 	local_irq_restore(flags);
 }
 EXPORT_SYMBOL_GPL(ftrace_dump);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 610d21355526d..580f2355a8357 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -143,6 +143,7 @@ struct kretprobe_trace_entry_head {
  *  NEED_RESCHED	- reschedule is requested
  *  HARDIRQ		- inside an interrupt handler
  *  SOFTIRQ		- inside a softirq handler
+ *  NEED_RESCHED_LAZY	- lazy reschedule is requested
  */
 enum trace_flag_type {
 	TRACE_FLAG_IRQS_OFF		= 0x01,
@@ -152,6 +153,7 @@ enum trace_flag_type {
 	TRACE_FLAG_SOFTIRQ		= 0x10,
 	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
 	TRACE_FLAG_NMI			= 0x40,
+	TRACE_FLAG_NEED_RESCHED_LAZY	= 0x80,
 };
 
 #define TRACE_BUF_SIZE		1024
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a85effb2373bf..a88a78c240bbb 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -182,6 +182,8 @@ static int trace_define_common_fields(void)
 	__common_field(unsigned char, flags);
 	__common_field(unsigned char, preempt_count);
 	__common_field(int, pid);
+	__common_field(unsigned char, migrate_disable);
+	__common_field(unsigned char, preempt_lazy_count);
 
 	return ret;
 }
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 4d1893564912d..38b332ce04b85 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -441,6 +441,7 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 {
 	char hardsoft_irq;
 	char need_resched;
+	char need_resched_lazy;
 	char irqs_off;
 	int hardirq;
 	int softirq;
@@ -471,6 +472,9 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 		break;
 	}
 
+	need_resched_lazy =
+		(entry->flags & TRACE_FLAG_NEED_RESCHED_LAZY) ? 'L' : '.';
+
 	hardsoft_irq =
 		(nmi && hardirq)     ? 'Z' :
 		nmi                  ? 'z' :
@@ -479,14 +483,25 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 		softirq              ? 's' :
 		                       '.' ;
 
-	trace_seq_printf(s, "%c%c%c",
-			 irqs_off, need_resched, hardsoft_irq);
+	trace_seq_printf(s, "%c%c%c%c",
+			 irqs_off, need_resched, need_resched_lazy,
+			 hardsoft_irq);
 
 	if (entry->preempt_count)
 		trace_seq_printf(s, "%x", entry->preempt_count);
 	else
 		trace_seq_putc(s, '.');
 
+	if (entry->preempt_lazy_count)
+		trace_seq_printf(s, "%x", entry->preempt_lazy_count);
+	else
+		trace_seq_putc(s, '.');
+
+	if (entry->migrate_disable)
+		trace_seq_printf(s, "%x", entry->migrate_disable);
+	else
+		trace_seq_putc(s, '.');
+
 	return !trace_seq_has_overflowed(s);
 }
 
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index e068c3c7189a1..da8ae429f1fdf 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -61,6 +61,23 @@ config CONSOLE_LOGLEVEL_QUIET
 	  will be used as the loglevel. IOW passing "quiet" will be the
 	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
 
+config CONSOLE_LOGLEVEL_EMERGENCY
+	int "Emergency console loglevel (1-15)"
+	range 1 15
+	default "5"
+	help
+	  The loglevel to determine if a console message is an emergency
+	  message.
+
+	  If supported by the console driver, emergency messages will be
+	  flushed to the console immediately. This can cause significant system
+	  latencies so the value should be set such that only significant
+	  messages are classified as emergency messages.
+
+	  Setting a default here is equivalent to passing in
+	  emergency_loglevel=<x> in the kernel bootargs. emergency_loglevel=<x>
+	  continues to override whatever value is specified here as well.
+
 config MESSAGE_LOGLEVEL_DEFAULT
 	int "Default message log level (1-7)"
 	range 1 7
@@ -1332,7 +1349,7 @@ config DEBUG_ATOMIC_SLEEP
 
 config DEBUG_LOCKING_API_SELFTESTS
 	bool "Locking API boot-time self-tests"
-	depends on DEBUG_KERNEL
+	depends on DEBUG_KERNEL && !PREEMPT_RT
 	help
 	  Say Y here if you want the kernel to run a short self-test during
 	  bootup. The self-test checks whether common types of locking bugs
diff --git a/lib/Makefile b/lib/Makefile
index a4a4c6864f518..e2822830764a1 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -32,7 +32,7 @@ KCSAN_SANITIZE_random32.o := n
 
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 rbtree.o radix-tree.o timerqueue.o xarray.o \
-	 idr.o extable.o sha1.o irq_regs.o argv_split.o \
+	 idr.o extable.o sha1.o irq_regs.o argv_split.o printk_ringbuffer.o \
 	 flex_proportions.o ratelimit.o show_mem.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
diff --git a/lib/bust_spinlocks.c b/lib/bust_spinlocks.c
index 8be59f84eaeaf..c6e083323d1b9 100644
--- a/lib/bust_spinlocks.c
+++ b/lib/bust_spinlocks.c
@@ -26,7 +26,6 @@ void bust_spinlocks(int yes)
 		unblank_screen();
 #endif
 		console_unblank();
-		if (--oops_in_progress == 0)
-			wake_up_klogd();
+		--oops_in_progress;
 	}
 }
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index fe4557955d976..f8bfd257d0bb3 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -537,7 +537,10 @@ __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 	struct debug_obj *obj;
 	unsigned long flags;
 
-	fill_pool();
+#ifdef CONFIG_PREEMPT_RT
+	if (preempt_count() == 0 && !irqs_disabled())
+#endif
+		fill_pool();
 
 	db = get_bucket((unsigned long) addr);
 
diff --git a/lib/irq_poll.c b/lib/irq_poll.c
index 2f17b488d58e1..7557bf7ecf1f1 100644
--- a/lib/irq_poll.c
+++ b/lib/irq_poll.c
@@ -37,6 +37,7 @@ void irq_poll_sched(struct irq_poll *iop)
 	list_add_tail(&iop->list, this_cpu_ptr(&blk_cpu_iopoll));
 	raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(irq_poll_sched);
 
@@ -72,6 +73,7 @@ void irq_poll_complete(struct irq_poll *iop)
 	local_irq_save(flags);
 	__irq_poll_complete(iop);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(irq_poll_complete);
 
@@ -96,6 +98,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
 		}
 
 		local_irq_enable();
+		preempt_check_resched_rt();
 
 		/* Even though interrupts have been re-enabled, this
 		 * access is safe because interrupts can only add new
@@ -133,6 +136,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
 		__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
 
 	local_irq_enable();
+	preempt_check_resched_rt();
 }
 
 /**
@@ -196,6 +200,7 @@ static int irq_poll_cpu_dead(unsigned int cpu)
 			 this_cpu_ptr(&blk_cpu_iopoll));
 	__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
 	local_irq_enable();
+	preempt_check_resched_rt();
 
 	return 0;
 }
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 14f44f59e7338..b110d073d2d2a 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -742,6 +742,8 @@ GENERATE_TESTCASE(init_held_rtmutex);
 #include "locking-selftest-spin-hardirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_spin)
 
+#ifndef CONFIG_PREEMPT_RT
+
 #include "locking-selftest-rlock-hardirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_rlock)
 
@@ -757,9 +759,12 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_rlock)
 #include "locking-selftest-wlock-softirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_wlock)
 
+#endif
+
 #undef E1
 #undef E2
 
+#ifndef CONFIG_PREEMPT_RT
 /*
  * Enabling hardirqs with a softirq-safe lock held:
  */
@@ -792,6 +797,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock)
 #undef E1
 #undef E2
 
+#endif
+
 /*
  * Enabling irqs with an irq-safe lock held:
  */
@@ -815,6 +822,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock)
 #include "locking-selftest-spin-hardirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_spin)
 
+#ifndef CONFIG_PREEMPT_RT
+
 #include "locking-selftest-rlock-hardirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_rlock)
 
@@ -830,6 +839,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_rlock)
 #include "locking-selftest-wlock-softirq.h"
 GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock)
 
+#endif
+
 #undef E1
 #undef E2
 
@@ -861,6 +872,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock)
 #include "locking-selftest-spin-hardirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_spin)
 
+#ifndef CONFIG_PREEMPT_RT
+
 #include "locking-selftest-rlock-hardirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_rlock)
 
@@ -876,6 +889,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_rlock)
 #include "locking-selftest-wlock-softirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock)
 
+#endif
+
 #undef E1
 #undef E2
 #undef E3
@@ -909,6 +924,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock)
 #include "locking-selftest-spin-hardirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_spin)
 
+#ifndef CONFIG_PREEMPT_RT
+
 #include "locking-selftest-rlock-hardirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_rlock)
 
@@ -924,10 +941,14 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_rlock)
 #include "locking-selftest-wlock-softirq.h"
 GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_wlock)
 
+#endif
+
 #undef E1
 #undef E2
 #undef E3
 
+#ifndef CONFIG_PREEMPT_RT
+
 /*
  * read-lock / write-lock irq inversion.
  *
@@ -990,6 +1011,10 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_inversion_soft_wlock)
 #undef E2
 #undef E3
 
+#endif
+
+#ifndef CONFIG_PREEMPT_RT
+
 /*
  * read-lock / write-lock recursion that is actually safe.
  */
@@ -1028,6 +1053,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft)
 #undef E2
 #undef E3
 
+#endif
+
 /*
  * read-lock / write-lock recursion that is unsafe.
  */
@@ -2058,6 +2085,7 @@ void locking_selftest(void)
 
 	printk("  --------------------------------------------------------------------------\n");
 
+#ifndef CONFIG_PREEMPT_RT
 	/*
 	 * irq-context testcases:
 	 */
@@ -2070,6 +2098,28 @@ void locking_selftest(void)
 
 	DO_TESTCASE_6x2("irq read-recursion", irq_read_recursion);
 //	DO_TESTCASE_6x2B("irq read-recursion #2", irq_read_recursion2);
+#else
+	/* On -rt, we only do hardirq context test for raw spinlock */
+	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 12);
+	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 21);
+
+	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 12);
+	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 21);
+
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 123);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 132);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 213);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 231);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 312);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 321);
+
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 123);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 132);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 213);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 231);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 312);
+	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 321);
+#endif
 
 	ww_tests();
 
diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
index 15ca78e1c7d4e..77bf84987cda4 100644
--- a/lib/nmi_backtrace.c
+++ b/lib/nmi_backtrace.c
@@ -75,12 +75,6 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
 		touch_softlockup_watchdog();
 	}
 
-	/*
-	 * Force flush any remote buffers that might be stuck in IRQ context
-	 * and therefore could not run their irq_work.
-	 */
-	printk_safe_flush();
-
 	clear_bit_unlock(0, &backtrace_flag);
 	put_cpu();
 }
diff --git a/lib/printk_ringbuffer.c b/lib/printk_ringbuffer.c
new file mode 100644
index 0000000000000..9a31d7dbdc005
--- /dev/null
+++ b/lib/printk_ringbuffer.c
@@ -0,0 +1,589 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/printk_ringbuffer.h>
+
+#define PRB_SIZE(rb) (1 << rb->size_bits)
+#define PRB_SIZE_BITMASK(rb) (PRB_SIZE(rb) - 1)
+#define PRB_INDEX(rb, lpos) (lpos & PRB_SIZE_BITMASK(rb))
+#define PRB_WRAPS(rb, lpos) (lpos >> rb->size_bits)
+#define PRB_WRAP_LPOS(rb, lpos, xtra) \
+	((PRB_WRAPS(rb, lpos) + xtra) << rb->size_bits)
+#define PRB_DATA_SIZE(e) (e->size - sizeof(struct prb_entry))
+#define PRB_DATA_ALIGN sizeof(long)
+
+static bool __prb_trylock(struct prb_cpulock *cpu_lock,
+			  unsigned int *cpu_store)
+{
+	unsigned long *flags;
+	unsigned int cpu;
+
+	cpu = get_cpu();
+
+	*cpu_store = atomic_read(&cpu_lock->owner);
+	/* memory barrier to ensure the current lock owner is visible */
+	smp_rmb();
+	if (*cpu_store == -1) {
+		flags = per_cpu_ptr(cpu_lock->irqflags, cpu);
+		local_irq_save(*flags);
+		if (atomic_try_cmpxchg_acquire(&cpu_lock->owner,
+					       cpu_store, cpu)) {
+			return true;
+		}
+		local_irq_restore(*flags);
+	} else if (*cpu_store == cpu) {
+		return true;
+	}
+
+	put_cpu();
+	return false;
+}
+
+/*
+ * prb_lock: Perform a processor-reentrant spin lock.
+ * @cpu_lock: A pointer to the lock object.
+ * @cpu_store: A "flags" pointer to store lock status information.
+ *
+ * If no processor has the lock, the calling processor takes the lock and
+ * becomes the owner. If the calling processor is already the owner of the
+ * lock, this function succeeds immediately. If lock is locked by another
+ * processor, this function spins until the calling processor becomes the
+ * owner.
+ *
+ * It is safe to call this function from any context and state.
+ */
+void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store)
+{
+	for (;;) {
+		if (__prb_trylock(cpu_lock, cpu_store))
+			break;
+		cpu_relax();
+	}
+}
+
+/*
+ * prb_unlock: Perform a processor-reentrant spin unlock.
+ * @cpu_lock: A pointer to the lock object.
+ * @cpu_store: A "flags" object storing lock status information.
+ *
+ * Release the lock. The calling processor must be the owner of the lock.
+ *
+ * It is safe to call this function from any context and state.
+ */
+void prb_unlock(struct prb_cpulock *cpu_lock, unsigned int cpu_store)
+{
+	unsigned long *flags;
+	unsigned int cpu;
+
+	cpu = atomic_read(&cpu_lock->owner);
+	atomic_set_release(&cpu_lock->owner, cpu_store);
+
+	if (cpu_store == -1) {
+		flags = per_cpu_ptr(cpu_lock->irqflags, cpu);
+		local_irq_restore(*flags);
+	}
+
+	put_cpu();
+}
+
+static struct prb_entry *to_entry(struct printk_ringbuffer *rb,
+				  unsigned long lpos)
+{
+	char *buffer = rb->buffer;
+	buffer += PRB_INDEX(rb, lpos);
+	return (struct prb_entry *)buffer;
+}
+
+static int calc_next(struct printk_ringbuffer *rb, unsigned long tail,
+		     unsigned long lpos, int size, unsigned long *calced_next)
+{
+	unsigned long next_lpos;
+	int ret = 0;
+again:
+	next_lpos = lpos + size;
+	if (next_lpos - tail > PRB_SIZE(rb))
+		return -1;
+
+	if (PRB_WRAPS(rb, lpos) != PRB_WRAPS(rb, next_lpos)) {
+		lpos = PRB_WRAP_LPOS(rb, next_lpos, 0);
+		ret |= 1;
+		goto again;
+	}
+
+	*calced_next = next_lpos;
+	return ret;
+}
+
+static bool push_tail(struct printk_ringbuffer *rb, unsigned long tail)
+{
+	unsigned long new_tail;
+	struct prb_entry *e;
+	unsigned long head;
+
+	if (tail != atomic_long_read(&rb->tail))
+		return true;
+
+	e = to_entry(rb, tail);
+	if (e->size != -1)
+		new_tail = tail + e->size;
+	else
+		new_tail = PRB_WRAP_LPOS(rb, tail, 1);
+
+	/* make sure the new tail does not overtake the head */
+	head = atomic_long_read(&rb->head);
+	if (head - new_tail > PRB_SIZE(rb))
+		return false;
+
+	atomic_long_cmpxchg(&rb->tail, tail, new_tail);
+	return true;
+}
+
+/*
+ * prb_commit: Commit a reserved entry to the ring buffer.
+ * @h: An entry handle referencing the data entry to commit.
+ *
+ * Commit data that has been reserved using prb_reserve(). Once the data
+ * block has been committed, it can be invalidated at any time. If a writer
+ * is interested in using the data after committing, the writer should make
+ * its own copy first or use the prb_iter_ reader functions to access the
+ * data in the ring buffer.
+ *
+ * It is safe to call this function from any context and state.
+ */
+void prb_commit(struct prb_handle *h)
+{
+	struct printk_ringbuffer *rb = h->rb;
+	bool changed = false;
+	struct prb_entry *e;
+	unsigned long head;
+	unsigned long res;
+
+	for (;;) {
+		if (atomic_read(&rb->ctx) != 1) {
+			/* the interrupted context will fixup head */
+			atomic_dec(&rb->ctx);
+			break;
+		}
+		/* assign sequence numbers before moving head */
+		head = atomic_long_read(&rb->head);
+		res = atomic_long_read(&rb->reserve);
+		while (head != res) {
+			e = to_entry(rb, head);
+			if (e->size == -1) {
+				head = PRB_WRAP_LPOS(rb, head, 1);
+				continue;
+			}
+			while (atomic_long_read(&rb->lost)) {
+				atomic_long_dec(&rb->lost);
+				rb->seq++;
+			}
+			e->seq = ++rb->seq;
+			head += e->size;
+			changed = true;
+		}
+		atomic_long_set_release(&rb->head, res);
+
+		atomic_dec(&rb->ctx);
+
+		if (atomic_long_read(&rb->reserve) == res)
+			break;
+		atomic_inc(&rb->ctx);
+	}
+
+	prb_unlock(rb->cpulock, h->cpu);
+
+	if (changed) {
+		atomic_long_inc(&rb->wq_counter);
+		if (wq_has_sleeper(rb->wq)) {
+#ifdef CONFIG_IRQ_WORK
+			irq_work_queue(rb->wq_work);
+#else
+			if (!in_nmi())
+				wake_up_interruptible_all(rb->wq);
+#endif
+		}
+	}
+}
+
+/*
+ * prb_reserve: Reserve an entry within a ring buffer.
+ * @h: An entry handle to be setup and reference an entry.
+ * @rb: A ring buffer to reserve data within.
+ * @size: The number of bytes to reserve.
+ *
+ * Reserve an entry of at least @size bytes to be used by the caller. If
+ * successful, the data region of the entry belongs to the caller and cannot
+ * be invalidated by any other task/context. For this reason, the caller
+ * should call prb_commit() as quickly as possible in order to avoid preventing
+ * other tasks/contexts from reserving data in the case that the ring buffer
+ * has wrapped.
+ *
+ * It is safe to call this function from any context and state.
+ *
+ * Returns a pointer to the reserved entry (and @h is setup to reference that
+ * entry) or NULL if it was not possible to reserve data.
+ */
+char *prb_reserve(struct prb_handle *h, struct printk_ringbuffer *rb,
+		  unsigned int size)
+{
+	unsigned long tail, res1, res2;
+	int ret;
+
+	if (size == 0)
+		return NULL;
+	size += sizeof(struct prb_entry);
+	size += PRB_DATA_ALIGN - 1;
+	size &= ~(PRB_DATA_ALIGN - 1);
+	if (size >= PRB_SIZE(rb))
+		return NULL;
+
+	h->rb = rb;
+	prb_lock(rb->cpulock, &h->cpu);
+
+	atomic_inc(&rb->ctx);
+
+	do {
+		for (;;) {
+			tail = atomic_long_read(&rb->tail);
+			res1 = atomic_long_read(&rb->reserve);
+			ret = calc_next(rb, tail, res1, size, &res2);
+			if (ret >= 0)
+				break;
+			if (!push_tail(rb, tail)) {
+				prb_commit(h);
+				return NULL;
+			}
+		}
+	} while (!atomic_long_try_cmpxchg_acquire(&rb->reserve, &res1, res2));
+
+	h->entry = to_entry(rb, res1);
+
+	if (ret) {
+		/* handle wrap */
+		h->entry->size = -1;
+		h->entry = to_entry(rb, PRB_WRAP_LPOS(rb, res2, 0));
+	}
+
+	h->entry->size = size;
+
+	return &h->entry->data[0];
+}
+
+/*
+ * prb_iter_copy: Copy an iterator.
+ * @dest: The iterator to copy to.
+ * @src: The iterator to copy from.
+ *
+ * Make a deep copy of an iterator. This is particularly useful for making
+ * backup copies of an iterator in case a form of rewinding it needed.
+ *
+ * It is safe to call this function from any context and state. But
+ * note that this function is not atomic. Callers should not make copies
+ * to/from iterators that can be accessed by other tasks/contexts.
+ */
+void prb_iter_copy(struct prb_iterator *dest, struct prb_iterator *src)
+{
+	memcpy(dest, src, sizeof(*dest));
+}
+
+/*
+ * prb_iter_init: Initialize an iterator for a ring buffer.
+ * @iter: The iterator to initialize.
+ * @rb: A ring buffer to that @iter should iterate.
+ * @seq: The sequence number of the position preceding the first record.
+ *       May be NULL.
+ *
+ * Initialize an iterator to be used with a specified ring buffer. If @seq
+ * is non-NULL, it will be set such that prb_iter_next() will provide a
+ * sequence value of "@seq + 1" if no records were missed.
+ *
+ * It is safe to call this function from any context and state.
+ */
+void prb_iter_init(struct prb_iterator *iter, struct printk_ringbuffer *rb,
+		   u64 *seq)
+{
+	memset(iter, 0, sizeof(*iter));
+	iter->rb = rb;
+	iter->lpos = PRB_INIT;
+
+	if (!seq)
+		return;
+
+	for (;;) {
+		struct prb_iterator tmp_iter;
+		int ret;
+
+		prb_iter_copy(&tmp_iter, iter);
+
+		ret = prb_iter_next(&tmp_iter, NULL, 0, seq);
+		if (ret < 0)
+			continue;
+
+		if (ret == 0)
+			*seq = 0;
+		else
+			(*seq)--;
+		break;
+	}
+}
+
+static bool is_valid(struct printk_ringbuffer *rb, unsigned long lpos)
+{
+	unsigned long head, tail;
+
+	tail = atomic_long_read(&rb->tail);
+	head = atomic_long_read(&rb->head);
+	head -= tail;
+	lpos -= tail;
+
+	if (lpos >= head)
+		return false;
+	return true;
+}
+
+/*
+ * prb_iter_data: Retrieve the record data at the current position.
+ * @iter: Iterator tracking the current position.
+ * @buf: A buffer to store the data of the record. May be NULL.
+ * @size: The size of @buf. (Ignored if @buf is NULL.)
+ * @seq: The sequence number of the record. May be NULL.
+ *
+ * If @iter is at a record, provide the data and/or sequence number of that
+ * record (if specified by the caller).
+ *
+ * It is safe to call this function from any context and state.
+ *
+ * Returns >=0 if the current record contains valid data (returns 0 if @buf
+ * is NULL or returns the size of the data block if @buf is non-NULL) or
+ * -EINVAL if @iter is now invalid.
+ */
+int prb_iter_data(struct prb_iterator *iter, char *buf, int size, u64 *seq)
+{
+	struct printk_ringbuffer *rb = iter->rb;
+	unsigned long lpos = iter->lpos;
+	unsigned int datsize = 0;
+	struct prb_entry *e;
+
+	if (buf || seq) {
+		e = to_entry(rb, lpos);
+		if (!is_valid(rb, lpos))
+			return -EINVAL;
+		/* memory barrier to ensure valid lpos */
+		smp_rmb();
+		if (buf) {
+			datsize = PRB_DATA_SIZE(e);
+			/* memory barrier to ensure load of datsize */
+			smp_rmb();
+			if (!is_valid(rb, lpos))
+				return -EINVAL;
+			if (PRB_INDEX(rb, lpos) + datsize >
+			    PRB_SIZE(rb) - PRB_DATA_ALIGN) {
+				return -EINVAL;
+			}
+			if (size > datsize)
+				size = datsize;
+			memcpy(buf, &e->data[0], size);
+		}
+		if (seq)
+			*seq = e->seq;
+		/* memory barrier to ensure loads of entry data */
+		smp_rmb();
+	}
+
+	if (!is_valid(rb, lpos))
+		return -EINVAL;
+
+	return datsize;
+}
+
+/*
+ * prb_iter_next: Advance to the next record.
+ * @iter: Iterator tracking the current position.
+ * @buf: A buffer to store the data of the next record. May be NULL.
+ * @size: The size of @buf. (Ignored if @buf is NULL.)
+ * @seq: The sequence number of the next record. May be NULL.
+ *
+ * If a next record is available, @iter is advanced and (if specified)
+ * the data and/or sequence number of that record are provided.
+ *
+ * It is safe to call this function from any context and state.
+ *
+ * Returns 1 if @iter was advanced, 0 if @iter is at the end of the list, or
+ * -EINVAL if @iter is now invalid.
+ */
+int prb_iter_next(struct prb_iterator *iter, char *buf, int size, u64 *seq)
+{
+	struct printk_ringbuffer *rb = iter->rb;
+	unsigned long next_lpos;
+	struct prb_entry *e;
+	unsigned int esize;
+
+	if (iter->lpos == PRB_INIT) {
+		next_lpos = atomic_long_read(&rb->tail);
+	} else {
+		if (!is_valid(rb, iter->lpos))
+			return -EINVAL;
+		/* memory barrier to ensure valid lpos */
+		smp_rmb();
+		e = to_entry(rb, iter->lpos);
+		esize = e->size;
+		/* memory barrier to ensure load of size */
+		smp_rmb();
+		if (!is_valid(rb, iter->lpos))
+			return -EINVAL;
+		next_lpos = iter->lpos + esize;
+	}
+	if (next_lpos == atomic_long_read(&rb->head))
+		return 0;
+	if (!is_valid(rb, next_lpos))
+		return -EINVAL;
+	/* memory barrier to ensure valid lpos */
+	smp_rmb();
+
+	iter->lpos = next_lpos;
+	e = to_entry(rb, iter->lpos);
+	esize = e->size;
+	/* memory barrier to ensure load of size */
+	smp_rmb();
+	if (!is_valid(rb, iter->lpos))
+		return -EINVAL;
+	if (esize == -1)
+		iter->lpos = PRB_WRAP_LPOS(rb, iter->lpos, 1);
+
+	if (prb_iter_data(iter, buf, size, seq) < 0)
+		return -EINVAL;
+
+	return 1;
+}
+
+/*
+ * prb_iter_wait_next: Advance to the next record, blocking if none available.
+ * @iter: Iterator tracking the current position.
+ * @buf: A buffer to store the data of the next record. May be NULL.
+ * @size: The size of @buf. (Ignored if @buf is NULL.)
+ * @seq: The sequence number of the next record. May be NULL.
+ *
+ * If a next record is already available, this function works like
+ * prb_iter_next(). Otherwise block interruptible until a next record is
+ * available.
+ *
+ * When a next record is available, @iter is advanced and (if specified)
+ * the data and/or sequence number of that record are provided.
+ *
+ * This function might sleep.
+ *
+ * Returns 1 if @iter was advanced, -EINVAL if @iter is now invalid, or
+ * -ERESTARTSYS if interrupted by a signal.
+ */
+int prb_iter_wait_next(struct prb_iterator *iter, char *buf, int size, u64 *seq)
+{
+	unsigned long last_seen;
+	int ret;
+
+	for (;;) {
+		last_seen = atomic_long_read(&iter->rb->wq_counter);
+
+		ret = prb_iter_next(iter, buf, size, seq);
+		if (ret != 0)
+			break;
+
+		ret = wait_event_interruptible(*iter->rb->wq,
+			last_seen != atomic_long_read(&iter->rb->wq_counter));
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
+/*
+ * prb_iter_seek: Seek forward to a specific record.
+ * @iter: Iterator to advance.
+ * @seq: Record number to advance to.
+ *
+ * Advance @iter such that a following call to prb_iter_data() will provide
+ * the contents of the specified record. If a record is specified that does
+ * not yet exist, advance @iter to the end of the record list.
+ *
+ * Note that iterators cannot be rewound. So if a record is requested that
+ * exists but is previous to @iter in position, @iter is considered invalid.
+ *
+ * It is safe to call this function from any context and state.
+ *
+ * Returns 1 on succces, 0 if specified record does not yet exist (@iter is
+ * now at the end of the list), or -EINVAL if @iter is now invalid.
+ */
+int prb_iter_seek(struct prb_iterator *iter, u64 seq)
+{
+	u64 cur_seq;
+	int ret;
+
+	/* first check if the iterator is already at the wanted seq */
+	if (seq == 0) {
+		if (iter->lpos == PRB_INIT)
+			return 1;
+		else
+			return -EINVAL;
+	}
+	if (iter->lpos != PRB_INIT) {
+		if (prb_iter_data(iter, NULL, 0, &cur_seq) >= 0) {
+			if (cur_seq == seq)
+				return 1;
+			if (cur_seq > seq)
+				return -EINVAL;
+		}
+	}
+
+	/* iterate to find the wanted seq */
+	for (;;) {
+		ret = prb_iter_next(iter, NULL, 0, &cur_seq);
+		if (ret <= 0)
+			break;
+
+		if (cur_seq == seq)
+			break;
+
+		if (cur_seq > seq) {
+			ret = -EINVAL;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+/*
+ * prb_buffer_size: Get the size of the ring buffer.
+ * @rb: The ring buffer to get the size of.
+ *
+ * Return the number of bytes used for the ring buffer entry storage area.
+ * Note that this area stores both entry header and entry data. Therefore
+ * this represents an upper bound to the amount of data that can be stored
+ * in the ring buffer.
+ *
+ * It is safe to call this function from any context and state.
+ *
+ * Returns the size in bytes of the entry storage area.
+ */
+int prb_buffer_size(struct printk_ringbuffer *rb)
+{
+	return PRB_SIZE(rb);
+}
+
+/*
+ * prb_inc_lost: Increment the seq counter to signal a lost record.
+ * @rb: The ring buffer to increment the seq of.
+ *
+ * Increment the seq counter so that a seq number is intentially missing
+ * for the readers. This allows readers to identify that a record is
+ * missing. A writer will typically use this function if prb_reserve()
+ * fails.
+ *
+ * It is safe to call this function from any context and state.
+ */
+void prb_inc_lost(struct printk_ringbuffer *rb)
+{
+	atomic_long_inc(&rb->lost);
+}
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 5d63a8857f361..5569dac27afe8 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -811,7 +811,7 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
 			flush_kernel_dcache_page(miter->page);
 
 		if (miter->__flags & SG_MITER_ATOMIC) {
-			WARN_ON_ONCE(preemptible());
+			WARN_ON_ONCE(!pagefault_disabled());
 			kunmap_atomic(miter->addr);
 		} else
 			kunmap(miter->page);
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 525222e4f4099..f2a93988cd9dd 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -23,6 +23,11 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
 	 * Kernel threads bound to a single CPU can safely use
 	 * smp_processor_id():
 	 */
+#if defined(CONFIG_PREEMPT_RT) && (defined(CONFIG_SMP) || defined(CONFIG_SCHED_DEBUG))
+	if (current->migrate_disable)
+		goto out;
+#endif
+
 	if (current->nr_cpus_allowed == 1)
 		goto out;
 
diff --git a/localversion-rt b/localversion-rt
new file mode 100644
index 0000000000000..c3054d08a1129
--- /dev/null
+++ b/localversion-rt
@@ -0,0 +1 @@
+-rt2
diff --git a/mm/Kconfig b/mm/Kconfig
index 6c974888f86f9..056460878a2b4 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -387,7 +387,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
 
 config TRANSPARENT_HUGEPAGE
 	bool "Transparent Hugepage Support"
-	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT
 	select COMPACTION
 	select XARRAY_MULTI
 	help
diff --git a/mm/highmem.c b/mm/highmem.c
index 64d8dea47dd1a..7d3065719ce80 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -31,8 +31,11 @@
 #include <asm/tlbflush.h>
 #include <linux/vmalloc.h>
 
+#ifndef CONFIG_PREEMPT_RT
 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
 DEFINE_PER_CPU(int, __kmap_atomic_idx);
+EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
+#endif
 #endif
 
 /*
@@ -108,8 +111,6 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
 atomic_long_t _totalhigh_pages __read_mostly;
 EXPORT_SYMBOL(_totalhigh_pages);
 
-EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
-
 unsigned int nr_free_highpages (void)
 {
 	struct zone *zone;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b807952b4d431..281e77c8c43d8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -63,6 +63,7 @@
 #include <net/sock.h>
 #include <net/ip.h>
 #include "slab.h"
+#include <linux/local_lock.h>
 
 #include <linux/uaccess.h>
 
@@ -90,6 +91,13 @@ bool cgroup_memory_noswap __read_mostly;
 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
 #endif
 
+struct event_lock {
+	local_lock_t l;
+};
+static DEFINE_PER_CPU(struct event_lock, event_lock) = {
+	.l      = INIT_LOCAL_LOCK(l),
+};
+
 /* Whether legacy memory+swap accounting is active */
 static bool do_memsw_account(void)
 {
@@ -2154,6 +2162,7 @@ void unlock_page_memcg(struct page *page)
 EXPORT_SYMBOL(unlock_page_memcg);
 
 struct memcg_stock_pcp {
+	local_lock_t lock;
 	struct mem_cgroup *cached; /* this never be root cgroup */
 	unsigned int nr_pages;
 
@@ -2205,7 +2214,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
 	if (nr_pages > MEMCG_CHARGE_BATCH)
 		return ret;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&memcg_stock.lock, flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
@@ -2213,7 +2222,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
 		ret = true;
 	}
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&memcg_stock.lock, flags);
 
 	return ret;
 }
@@ -2248,14 +2257,14 @@ static void drain_local_stock(struct work_struct *dummy)
 	 * The only protection from memory hotplug vs. drain_stock races is
 	 * that we always operate on local CPU stock here with IRQ disabled
 	 */
-	local_irq_save(flags);
+	local_lock_irqsave(&memcg_stock.lock, flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
 	drain_obj_stock(stock);
 	drain_stock(stock);
 	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&memcg_stock.lock, flags);
 }
 
 /*
@@ -2267,7 +2276,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
 	struct memcg_stock_pcp *stock;
 	unsigned long flags;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&memcg_stock.lock, flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (stock->cached != memcg) { /* reset if necessary */
@@ -2280,7 +2289,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
 	if (stock->nr_pages > MEMCG_CHARGE_BATCH)
 		drain_stock(stock);
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&memcg_stock.lock, flags);
 }
 
 /*
@@ -2300,7 +2309,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 	 * as well as workers from this path always operate on the local
 	 * per-cpu data. CPU up doesn't touch memcg_stock at all.
 	 */
-	curcpu = get_cpu();
+	curcpu = get_cpu_light();
 	for_each_online_cpu(cpu) {
 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
 		struct mem_cgroup *memcg;
@@ -2323,7 +2332,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 				schedule_work_on(cpu, &stock->work);
 		}
 	}
-	put_cpu();
+	put_cpu_light();
 	mutex_unlock(&percpu_charge_mutex);
 }
 
@@ -3084,7 +3093,7 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
 	unsigned long flags;
 	bool ret = false;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&memcg_stock.lock, flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
@@ -3092,7 +3101,7 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
 		ret = true;
 	}
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&memcg_stock.lock, flags);
 
 	return ret;
 }
@@ -3151,7 +3160,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
 	struct memcg_stock_pcp *stock;
 	unsigned long flags;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&memcg_stock.lock, flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
 	if (stock->cached_objcg != objcg) { /* reset if necessary */
@@ -3165,7 +3174,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
 	if (stock->nr_bytes > PAGE_SIZE)
 		drain_obj_stock(stock);
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&memcg_stock.lock, flags);
 }
 
 int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
@@ -5681,12 +5690,12 @@ static int mem_cgroup_move_account(struct page *page,
 
 	ret = 0;
 
-	local_irq_disable();
+	local_lock_irq(&event_lock.l);
 	mem_cgroup_charge_statistics(to, page, nr_pages);
 	memcg_check_events(to, page);
 	mem_cgroup_charge_statistics(from, page, -nr_pages);
 	memcg_check_events(from, page);
-	local_irq_enable();
+	local_unlock_irq(&event_lock.l);
 out_unlock:
 	unlock_page(page);
 out:
@@ -6722,10 +6731,10 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 	css_get(&memcg->css);
 	commit_charge(page, memcg);
 
-	local_irq_disable();
+	local_lock_irq(&event_lock.l);
 	mem_cgroup_charge_statistics(memcg, page, nr_pages);
 	memcg_check_events(memcg, page);
-	local_irq_enable();
+	local_unlock_irq(&event_lock.l);
 
 	if (PageSwapCache(page)) {
 		swp_entry_t entry = { .val = page_private(page) };
@@ -6769,11 +6778,11 @@ static void uncharge_batch(const struct uncharge_gather *ug)
 		memcg_oom_recover(ug->memcg);
 	}
 
-	local_irq_save(flags);
+	local_lock_irqsave(&event_lock.l, flags);
 	__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
 	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_pages);
 	memcg_check_events(ug->memcg, ug->dummy_page);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&event_lock.l, flags);
 }
 
 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
@@ -6921,10 +6930,10 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
 	css_get(&memcg->css);
 	commit_charge(newpage, memcg);
 
-	local_irq_save(flags);
+	local_lock_irqsave(&event_lock.l, flags);
 	mem_cgroup_charge_statistics(memcg, newpage, nr_pages);
 	memcg_check_events(memcg, newpage);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&event_lock.l, flags);
 }
 
 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
@@ -7044,9 +7053,13 @@ static int __init mem_cgroup_init(void)
 	cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
 				  memcg_hotplug_cpu_dead);
 
-	for_each_possible_cpu(cpu)
-		INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
-			  drain_local_stock);
+	for_each_possible_cpu(cpu) {
+		struct memcg_stock_pcp *stock;
+
+		stock = per_cpu_ptr(&memcg_stock, cpu);
+		INIT_WORK(&stock->work, drain_local_stock);
+		local_lock_init(&stock->lock);
+	}
 
 	for_each_node(node) {
 		struct mem_cgroup_tree_per_node *rtpn;
@@ -7095,6 +7108,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 	struct mem_cgroup *memcg, *swap_memcg;
 	unsigned int nr_entries;
 	unsigned short oldid;
+	unsigned long flags;
 
 	VM_BUG_ON_PAGE(PageLRU(page), page);
 	VM_BUG_ON_PAGE(page_count(page), page);
@@ -7140,9 +7154,13 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 	 * important here to have the interrupts disabled because it is the
 	 * only synchronisation we have for updating the per-CPU variables.
 	 */
+	local_lock_irqsave(&event_lock.l, flags);
+#ifndef CONFIG_PREEMPT_RT
 	VM_BUG_ON(!irqs_disabled());
+#endif
 	mem_cgroup_charge_statistics(memcg, page, -nr_entries);
 	memcg_check_events(memcg, page);
+	local_unlock_irqrestore(&event_lock.l, flags);
 
 	css_put(&memcg->css);
 }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fab5e97dc9ca5..78fd3975cc7fa 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -61,6 +61,7 @@
 #include <linux/hugetlb.h>
 #include <linux/sched/rt.h>
 #include <linux/sched/mm.h>
+#include <linux/local_lock.h>
 #include <linux/page_owner.h>
 #include <linux/kthread.h>
 #include <linux/memcontrol.h>
@@ -356,6 +357,13 @@ EXPORT_SYMBOL(nr_node_ids);
 EXPORT_SYMBOL(nr_online_nodes);
 #endif
 
+struct pa_lock {
+	local_lock_t l;
+};
+static DEFINE_PER_CPU(struct pa_lock, pa_lock) = {
+	.l	= INIT_LOCAL_LOCK(l),
+};
+
 int page_group_by_mobility_disabled __read_mostly;
 
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
@@ -1282,7 +1290,7 @@ static inline void prefetch_buddy(struct page *page)
 }
 
 /*
- * 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.
  *
@@ -1292,15 +1300,56 @@ static inline void prefetch_buddy(struct page *page)
  * And clear the zone's pages_scanned counter, to hold off the "all pages are
  * pinned" detection logic.
  */
-static void free_pcppages_bulk(struct zone *zone, int count,
-					struct per_cpu_pages *pcp)
+static void free_pcppages_bulk(struct zone *zone, struct list_head *head,
+			       bool zone_retry)
+{
+	bool isolated_pageblocks;
+	struct page *page, *tmp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&zone->lock, flags);
+	isolated_pageblocks = has_isolate_pageblock(zone);
+
+	/*
+	 * Use safe version since after __free_one_page(),
+	 * page->lru.next will not point to original list.
+	 */
+	list_for_each_entry_safe(page, tmp, head, lru) {
+		int mt = get_pcppage_migratetype(page);
+
+		if (page_zone(page) != zone) {
+			/*
+			 * free_unref_page_list() sorts pages by zone. If we end
+			 * up with pages from a different NUMA nodes belonging
+			 * to the same ZONE index then we need to redo with the
+			 * correct ZONE pointer. Skip the page for now, redo it
+			 * on the next iteration.
+			 */
+			WARN_ON_ONCE(zone_retry == false);
+			if (zone_retry)
+				continue;
+		}
+
+		/* MIGRATE_ISOLATE page should not go to pcplists */
+		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
+		/* Pageblock could have been isolated meanwhile */
+		if (unlikely(isolated_pageblocks))
+			mt = get_pageblock_migratetype(page);
+
+		list_del(&page->lru);
+		__free_one_page(page, page_to_pfn(page), zone, 0, mt, true);
+		trace_mm_page_pcpu_drain(page, 0, mt);
+	}
+	spin_unlock_irqrestore(&zone->lock, flags);
+}
+
+static void isolate_pcp_pages(int count, struct per_cpu_pages *pcp,
+			      struct list_head *dst)
 {
 	int migratetype = 0;
 	int batch_free = 0;
 	int prefetch_nr = 0;
-	bool isolated_pageblocks;
-	struct page *page, *tmp;
-	LIST_HEAD(head);
+	struct page *page;
 
 	/*
 	 * Ensure proper count is passed which otherwise would stuck in the
@@ -1337,7 +1386,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 			if (bulkfree_pcp_prepare(page))
 				continue;
 
-			list_add_tail(&page->lru, &head);
+			list_add_tail(&page->lru, dst);
 
 			/*
 			 * We are going to put the page back to the global
@@ -1352,26 +1401,6 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 				prefetch_buddy(page);
 		} while (--count && --batch_free && !list_empty(list));
 	}
-
-	spin_lock(&zone->lock);
-	isolated_pageblocks = has_isolate_pageblock(zone);
-
-	/*
-	 * Use safe version since after __free_one_page(),
-	 * page->lru.next will not point to original list.
-	 */
-	list_for_each_entry_safe(page, tmp, &head, lru) {
-		int mt = get_pcppage_migratetype(page);
-		/* MIGRATE_ISOLATE page should not go to pcplists */
-		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
-		/* Pageblock could have been isolated meanwhile */
-		if (unlikely(isolated_pageblocks))
-			mt = get_pageblock_migratetype(page);
-
-		__free_one_page(page, page_to_pfn(page), zone, 0, mt, true);
-		trace_mm_page_pcpu_drain(page, 0, mt);
-	}
-	spin_unlock(&zone->lock);
 }
 
 static void free_one_page(struct zone *zone,
@@ -1472,10 +1501,10 @@ static void __free_pages_ok(struct page *page, unsigned int order)
 		return;
 
 	migratetype = get_pfnblock_migratetype(page, pfn);
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	__count_vm_events(PGFREE, 1 << order);
 	free_one_page(page_zone(page), page, pfn, order, migratetype);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
 }
 
 void __free_pages_core(struct page *page, unsigned int order)
@@ -2876,13 +2905,18 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 {
 	unsigned long flags;
 	int to_drain, batch;
+	LIST_HEAD(dst);
 
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	batch = READ_ONCE(pcp->batch);
 	to_drain = min(pcp->count, batch);
 	if (to_drain > 0)
-		free_pcppages_bulk(zone, to_drain, pcp);
-	local_irq_restore(flags);
+		isolate_pcp_pages(to_drain, pcp, &dst);
+
+	local_unlock_irqrestore(&pa_lock.l, flags);
+
+	if (to_drain > 0)
+		free_pcppages_bulk(zone, &dst, false);
 }
 #endif
 
@@ -2898,14 +2932,21 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
 	unsigned long flags;
 	struct per_cpu_pageset *pset;
 	struct per_cpu_pages *pcp;
+	LIST_HEAD(dst);
+	int count;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	pset = per_cpu_ptr(zone->pageset, cpu);
 
 	pcp = &pset->pcp;
-	if (pcp->count)
-		free_pcppages_bulk(zone, pcp->count, pcp);
-	local_irq_restore(flags);
+	count = pcp->count;
+	if (count)
+		isolate_pcp_pages(count, pcp, &dst);
+
+	local_unlock_irqrestore(&pa_lock.l, flags);
+
+	if (count)
+		free_pcppages_bulk(zone, &dst, false);
 }
 
 /*
@@ -2953,9 +2994,9 @@ static void drain_local_pages_wq(struct work_struct *work)
 	 * cpu which is allright but we also have to make sure to not move to
 	 * a different one.
 	 */
-	preempt_disable();
+	migrate_disable();
 	drain_local_pages(drain->zone);
-	preempt_enable();
+	migrate_enable();
 }
 
 /*
@@ -3104,7 +3145,8 @@ static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
 	return true;
 }
 
-static void free_unref_page_commit(struct page *page, unsigned long pfn)
+static void free_unref_page_commit(struct page *page, unsigned long pfn,
+				   struct list_head *dst)
 {
 	struct zone *zone = page_zone(page);
 	struct per_cpu_pages *pcp;
@@ -3133,7 +3175,8 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
 	pcp->count++;
 	if (pcp->count >= pcp->high) {
 		unsigned long batch = READ_ONCE(pcp->batch);
-		free_pcppages_bulk(zone, batch, pcp);
+
+		isolate_pcp_pages(batch, pcp, dst);
 	}
 }
 
@@ -3144,13 +3187,17 @@ void free_unref_page(struct page *page)
 {
 	unsigned long flags;
 	unsigned long pfn = page_to_pfn(page);
+	struct zone *zone = page_zone(page);
+	LIST_HEAD(dst);
 
 	if (!free_unref_page_prepare(page, pfn))
 		return;
 
-	local_irq_save(flags);
-	free_unref_page_commit(page, pfn);
-	local_irq_restore(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
+	free_unref_page_commit(page, pfn, &dst);
+	local_unlock_irqrestore(&pa_lock.l, flags);
+	if (!list_empty(&dst))
+		free_pcppages_bulk(zone, &dst, false);
 }
 
 /*
@@ -3161,6 +3208,11 @@ void free_unref_page_list(struct list_head *list)
 	struct page *page, *next;
 	unsigned long flags, pfn;
 	int batch_count = 0;
+	struct list_head dsts[__MAX_NR_ZONES];
+	int i;
+
+	for (i = 0; i < __MAX_NR_ZONES; i++)
+		INIT_LIST_HEAD(&dsts[i]);
 
 	/* Prepare pages for freeing */
 	list_for_each_entry_safe(page, next, list, lru) {
@@ -3170,25 +3222,42 @@ void free_unref_page_list(struct list_head *list)
 		set_page_private(page, pfn);
 	}
 
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	list_for_each_entry_safe(page, next, list, lru) {
 		unsigned long pfn = page_private(page);
+		enum zone_type type;
 
 		set_page_private(page, 0);
 		trace_mm_page_free_batched(page);
-		free_unref_page_commit(page, pfn);
+		type = page_zonenum(page);
+		free_unref_page_commit(page, pfn, &dsts[type]);
 
 		/*
 		 * Guard against excessive IRQ disabled times when we get
 		 * a large list of pages to free.
 		 */
 		if (++batch_count == SWAP_CLUSTER_MAX) {
-			local_irq_restore(flags);
+			local_unlock_irqrestore(&pa_lock.l, flags);
 			batch_count = 0;
-			local_irq_save(flags);
+			local_lock_irqsave(&pa_lock.l, flags);
 		}
 	}
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
+
+	for (i = 0; i < __MAX_NR_ZONES; ) {
+		struct page *page;
+		struct zone *zone;
+
+		if (list_empty(&dsts[i])) {
+			i++;
+			continue;
+		}
+
+		page = list_first_entry(&dsts[i], struct page, lru);
+		zone = page_zone(page);
+
+		free_pcppages_bulk(zone, &dsts[i], true);
+	}
 }
 
 /*
@@ -3342,7 +3411,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
 	struct page *page;
 	unsigned long flags;
 
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	pcp = &this_cpu_ptr(zone->pageset)->pcp;
 	list = &pcp->lists[migratetype];
 	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
@@ -3350,7 +3419,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
 		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
 		zone_statistics(preferred_zone, zone);
 	}
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
 	return page;
 }
 
@@ -3377,7 +3446,8 @@ struct page *rmqueue(struct zone *preferred_zone,
 	 * allocate greater than order-1 page units with __GFP_NOFAIL.
 	 */
 	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
-	spin_lock_irqsave(&zone->lock, flags);
+	local_lock_irqsave(&pa_lock.l, flags);
+	spin_lock(&zone->lock);
 
 	do {
 		page = NULL;
@@ -3397,7 +3467,7 @@ struct page *rmqueue(struct zone *preferred_zone,
 
 	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
 	zone_statistics(preferred_zone, zone);
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
 
 out:
 	/* Separate test+clear to avoid unnecessary atomics */
@@ -3410,7 +3480,7 @@ struct page *rmqueue(struct zone *preferred_zone,
 	return page;
 
 failed:
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
 	return NULL;
 }
 
@@ -8681,7 +8751,7 @@ void zone_pcp_reset(struct zone *zone)
 	struct per_cpu_pageset *pset;
 
 	/* avoid races with drain_pages()  */
-	local_irq_save(flags);
+	local_lock_irqsave(&pa_lock.l, flags);
 	if (zone->pageset != &boot_pageset) {
 		for_each_online_cpu(cpu) {
 			pset = per_cpu_ptr(zone->pageset, cpu);
@@ -8690,7 +8760,7 @@ void zone_pcp_reset(struct zone *zone)
 		free_percpu(zone->pageset);
 		zone->pageset = &boot_pageset;
 	}
-	local_irq_restore(flags);
+	local_unlock_irqrestore(&pa_lock.l, flags);
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
diff --git a/mm/shmem.c b/mm/shmem.c
index 271548ca20f31..be2ac6f2864b9 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -278,9 +278,9 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
 	ino_t ino;
 
 	if (!(sb->s_flags & SB_KERNMOUNT)) {
-		spin_lock(&sbinfo->stat_lock);
+		raw_spin_lock(&sbinfo->stat_lock);
 		if (!sbinfo->free_inodes) {
-			spin_unlock(&sbinfo->stat_lock);
+			raw_spin_unlock(&sbinfo->stat_lock);
 			return -ENOSPC;
 		}
 		sbinfo->free_inodes--;
@@ -302,7 +302,7 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
 			}
 			*inop = ino;
 		}
-		spin_unlock(&sbinfo->stat_lock);
+		raw_spin_unlock(&sbinfo->stat_lock);
 	} else if (inop) {
 		/*
 		 * __shmem_file_setup, one of our callers, is lock-free: it
@@ -317,13 +317,14 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
 		 * to worry about things like glibc compatibility.
 		 */
 		ino_t *next_ino;
+
 		next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu());
 		ino = *next_ino;
 		if (unlikely(ino % SHMEM_INO_BATCH == 0)) {
-			spin_lock(&sbinfo->stat_lock);
+			raw_spin_lock(&sbinfo->stat_lock);
 			ino = sbinfo->next_ino;
 			sbinfo->next_ino += SHMEM_INO_BATCH;
-			spin_unlock(&sbinfo->stat_lock);
+			raw_spin_unlock(&sbinfo->stat_lock);
 			if (unlikely(is_zero_ino(ino)))
 				ino++;
 		}
@@ -339,9 +340,9 @@ static void shmem_free_inode(struct super_block *sb)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 	if (sbinfo->max_inodes) {
-		spin_lock(&sbinfo->stat_lock);
+		raw_spin_lock(&sbinfo->stat_lock);
 		sbinfo->free_inodes++;
-		spin_unlock(&sbinfo->stat_lock);
+		raw_spin_unlock(&sbinfo->stat_lock);
 	}
 }
 
@@ -1477,10 +1478,10 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
 {
 	struct mempolicy *mpol = NULL;
 	if (sbinfo->mpol) {
-		spin_lock(&sbinfo->stat_lock);	/* prevent replace/use races */
+		raw_spin_lock(&sbinfo->stat_lock);	/* prevent replace/use races */
 		mpol = sbinfo->mpol;
 		mpol_get(mpol);
-		spin_unlock(&sbinfo->stat_lock);
+		raw_spin_unlock(&sbinfo->stat_lock);
 	}
 	return mpol;
 }
@@ -3580,9 +3581,10 @@ static int shmem_reconfigure(struct fs_context *fc)
 	struct shmem_options *ctx = fc->fs_private;
 	struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb);
 	unsigned long inodes;
+	struct mempolicy *mpol = NULL;
 	const char *err;
 
-	spin_lock(&sbinfo->stat_lock);
+	raw_spin_lock(&sbinfo->stat_lock);
 	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
 	if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) {
 		if (!sbinfo->max_blocks) {
@@ -3627,14 +3629,15 @@ static int shmem_reconfigure(struct fs_context *fc)
 	 * Preserve previous mempolicy unless mpol remount option was specified.
 	 */
 	if (ctx->mpol) {
-		mpol_put(sbinfo->mpol);
+		mpol = sbinfo->mpol;
 		sbinfo->mpol = ctx->mpol;	/* transfers initial ref */
 		ctx->mpol = NULL;
 	}
-	spin_unlock(&sbinfo->stat_lock);
+	raw_spin_unlock(&sbinfo->stat_lock);
+	mpol_put(mpol);
 	return 0;
 out:
-	spin_unlock(&sbinfo->stat_lock);
+	raw_spin_unlock(&sbinfo->stat_lock);
 	return invalfc(fc, "%s", err);
 }
 
@@ -3751,7 +3754,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 	sbinfo->mpol = ctx->mpol;
 	ctx->mpol = NULL;
 
-	spin_lock_init(&sbinfo->stat_lock);
+	raw_spin_lock_init(&sbinfo->stat_lock);
 	if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
 		goto failed;
 	spin_lock_init(&sbinfo->shrinklist_lock);
diff --git a/mm/slab.c b/mm/slab.c
index 3160dff6fd767..6959f04ffbac8 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -233,7 +233,7 @@ static void kmem_cache_node_init(struct kmem_cache_node *parent)
 	parent->shared = NULL;
 	parent->alien = NULL;
 	parent->colour_next = 0;
-	spin_lock_init(&parent->list_lock);
+	raw_spin_lock_init(&parent->list_lock);
 	parent->free_objects = 0;
 	parent->free_touched = 0;
 }
@@ -558,9 +558,9 @@ static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
 	page_node = page_to_nid(page);
 	n = get_node(cachep, page_node);
 
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	free_block(cachep, &objp, 1, page_node, &list);
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 
 	slabs_destroy(cachep, &list);
 }
@@ -698,7 +698,7 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
 	struct kmem_cache_node *n = get_node(cachep, node);
 
 	if (ac->avail) {
-		spin_lock(&n->list_lock);
+		raw_spin_lock(&n->list_lock);
 		/*
 		 * Stuff objects into the remote nodes shared array first.
 		 * That way we could avoid the overhead of putting the objects
@@ -709,7 +709,7 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
 
 		free_block(cachep, ac->entry, ac->avail, node, list);
 		ac->avail = 0;
-		spin_unlock(&n->list_lock);
+		raw_spin_unlock(&n->list_lock);
 	}
 }
 
@@ -782,9 +782,9 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
 		slabs_destroy(cachep, &list);
 	} else {
 		n = get_node(cachep, page_node);
-		spin_lock(&n->list_lock);
+		raw_spin_lock(&n->list_lock);
 		free_block(cachep, &objp, 1, page_node, &list);
-		spin_unlock(&n->list_lock);
+		raw_spin_unlock(&n->list_lock);
 		slabs_destroy(cachep, &list);
 	}
 	return 1;
@@ -825,10 +825,10 @@ static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
 	 */
 	n = get_node(cachep, node);
 	if (n) {
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 		n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
 				cachep->num;
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 
 		return 0;
 	}
@@ -907,7 +907,7 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep,
 		goto fail;
 
 	n = get_node(cachep, node);
-	spin_lock_irq(&n->list_lock);
+	raw_spin_lock_irq(&n->list_lock);
 	if (n->shared && force_change) {
 		free_block(cachep, n->shared->entry,
 				n->shared->avail, node, &list);
@@ -925,7 +925,7 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep,
 		new_alien = NULL;
 	}
 
-	spin_unlock_irq(&n->list_lock);
+	raw_spin_unlock_irq(&n->list_lock);
 	slabs_destroy(cachep, &list);
 
 	/*
@@ -964,7 +964,7 @@ static void cpuup_canceled(long cpu)
 		if (!n)
 			continue;
 
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 
 		/* Free limit for this kmem_cache_node */
 		n->free_limit -= cachep->batchcount;
@@ -975,7 +975,7 @@ static void cpuup_canceled(long cpu)
 		nc->avail = 0;
 
 		if (!cpumask_empty(mask)) {
-			spin_unlock_irq(&n->list_lock);
+			raw_spin_unlock_irq(&n->list_lock);
 			goto free_slab;
 		}
 
@@ -989,7 +989,7 @@ static void cpuup_canceled(long cpu)
 		alien = n->alien;
 		n->alien = NULL;
 
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 
 		kfree(shared);
 		if (alien) {
@@ -1173,7 +1173,7 @@ static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *
 	/*
 	 * Do not assume that spinlocks can be initialized via memcpy:
 	 */
-	spin_lock_init(&ptr->list_lock);
+	raw_spin_lock_init(&ptr->list_lock);
 
 	MAKE_ALL_LISTS(cachep, ptr, nodeid);
 	cachep->node[nodeid] = ptr;
@@ -1344,11 +1344,11 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
 	for_each_kmem_cache_node(cachep, node, n) {
 		unsigned long total_slabs, free_slabs, free_objs;
 
-		spin_lock_irqsave(&n->list_lock, flags);
+		raw_spin_lock_irqsave(&n->list_lock, flags);
 		total_slabs = n->total_slabs;
 		free_slabs = n->free_slabs;
 		free_objs = n->free_objects;
-		spin_unlock_irqrestore(&n->list_lock, flags);
+		raw_spin_unlock_irqrestore(&n->list_lock, flags);
 
 		pr_warn("  node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
 			node, total_slabs - free_slabs, total_slabs,
@@ -2102,7 +2102,7 @@ static void check_spinlock_acquired(struct kmem_cache *cachep)
 {
 #ifdef CONFIG_SMP
 	check_irq_off();
-	assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
+	assert_raw_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
 #endif
 }
 
@@ -2110,7 +2110,7 @@ static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
 {
 #ifdef CONFIG_SMP
 	check_irq_off();
-	assert_spin_locked(&get_node(cachep, node)->list_lock);
+	assert_raw_spin_locked(&get_node(cachep, node)->list_lock);
 #endif
 }
 
@@ -2150,9 +2150,9 @@ static void do_drain(void *arg)
 	check_irq_off();
 	ac = cpu_cache_get(cachep);
 	n = get_node(cachep, node);
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	free_block(cachep, ac->entry, ac->avail, node, &list);
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	slabs_destroy(cachep, &list);
 	ac->avail = 0;
 }
@@ -2170,9 +2170,9 @@ static void drain_cpu_caches(struct kmem_cache *cachep)
 			drain_alien_cache(cachep, n->alien);
 
 	for_each_kmem_cache_node(cachep, node, n) {
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 		drain_array_locked(cachep, n->shared, node, true, &list);
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 
 		slabs_destroy(cachep, &list);
 	}
@@ -2194,10 +2194,10 @@ static int drain_freelist(struct kmem_cache *cache,
 	nr_freed = 0;
 	while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
 
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 		p = n->slabs_free.prev;
 		if (p == &n->slabs_free) {
-			spin_unlock_irq(&n->list_lock);
+			raw_spin_unlock_irq(&n->list_lock);
 			goto out;
 		}
 
@@ -2210,7 +2210,7 @@ static int drain_freelist(struct kmem_cache *cache,
 		 * to the cache.
 		 */
 		n->free_objects -= cache->num;
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 		slab_destroy(cache, page);
 		nr_freed++;
 	}
@@ -2648,7 +2648,7 @@ static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
 	INIT_LIST_HEAD(&page->slab_list);
 	n = get_node(cachep, page_to_nid(page));
 
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	n->total_slabs++;
 	if (!page->active) {
 		list_add_tail(&page->slab_list, &n->slabs_free);
@@ -2658,7 +2658,7 @@ static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
 
 	STATS_INC_GROWN(cachep);
 	n->free_objects += cachep->num - page->active;
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 
 	fixup_objfreelist_debug(cachep, &list);
 }
@@ -2824,7 +2824,7 @@ static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
 {
 	struct page *page;
 
-	assert_spin_locked(&n->list_lock);
+	assert_raw_spin_locked(&n->list_lock);
 	page = list_first_entry_or_null(&n->slabs_partial, struct page,
 					slab_list);
 	if (!page) {
@@ -2851,10 +2851,10 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
 	if (!gfp_pfmemalloc_allowed(flags))
 		return NULL;
 
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	page = get_first_slab(n, true);
 	if (!page) {
-		spin_unlock(&n->list_lock);
+		raw_spin_unlock(&n->list_lock);
 		return NULL;
 	}
 
@@ -2863,7 +2863,7 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
 
 	fixup_slab_list(cachep, n, page, &list);
 
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	fixup_objfreelist_debug(cachep, &list);
 
 	return obj;
@@ -2922,7 +2922,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 	if (!n->free_objects && (!shared || !shared->avail))
 		goto direct_grow;
 
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	shared = READ_ONCE(n->shared);
 
 	/* See if we can refill from the shared array */
@@ -2946,7 +2946,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 must_grow:
 	n->free_objects -= ac->avail;
 alloc_done:
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	fixup_objfreelist_debug(cachep, &list);
 
 direct_grow:
@@ -3171,7 +3171,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 	BUG_ON(!n);
 
 	check_irq_off();
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	page = get_first_slab(n, false);
 	if (!page)
 		goto must_grow;
@@ -3189,12 +3189,12 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 
 	fixup_slab_list(cachep, n, page, &list);
 
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	fixup_objfreelist_debug(cachep, &list);
 	return obj;
 
 must_grow:
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
 	if (page) {
 		/* This slab isn't counted yet so don't update free_objects */
@@ -3372,7 +3372,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
 
 	check_irq_off();
 	n = get_node(cachep, node);
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	if (n->shared) {
 		struct array_cache *shared_array = n->shared;
 		int max = shared_array->limit - shared_array->avail;
@@ -3401,7 +3401,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
 		STATS_SET_FREEABLE(cachep, i);
 	}
 #endif
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	slabs_destroy(cachep, &list);
 	ac->avail -= batchcount;
 	memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
@@ -3830,9 +3830,9 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
 
 		node = cpu_to_mem(cpu);
 		n = get_node(cachep, node);
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 		free_block(cachep, ac->entry, ac->avail, node, &list);
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 		slabs_destroy(cachep, &list);
 	}
 	free_percpu(prev);
@@ -3927,9 +3927,9 @@ static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
 		return;
 	}
 
-	spin_lock_irq(&n->list_lock);
+	raw_spin_lock_irq(&n->list_lock);
 	drain_array_locked(cachep, ac, node, false, &list);
-	spin_unlock_irq(&n->list_lock);
+	raw_spin_unlock_irq(&n->list_lock);
 
 	slabs_destroy(cachep, &list);
 }
@@ -4013,7 +4013,7 @@ void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
 
 	for_each_kmem_cache_node(cachep, node, n) {
 		check_irq_on();
-		spin_lock_irq(&n->list_lock);
+		raw_spin_lock_irq(&n->list_lock);
 
 		total_slabs += n->total_slabs;
 		free_slabs += n->free_slabs;
@@ -4022,7 +4022,7 @@ void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
 		if (n->shared)
 			shared_avail += n->shared->avail;
 
-		spin_unlock_irq(&n->list_lock);
+		raw_spin_unlock_irq(&n->list_lock);
 	}
 	num_objs = total_slabs * cachep->num;
 	active_slabs = total_slabs - free_slabs;
diff --git a/mm/slab.h b/mm/slab.h
index 6cc323f1313af..089bcef627e62 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -530,7 +530,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
  * The slab lists for all objects.
  */
 struct kmem_cache_node {
-	spinlock_t list_lock;
+	raw_spinlock_t list_lock;
 
 #ifdef CONFIG_SLAB
 	struct list_head slabs_partial;	/* partial list first, better asm code */
diff --git a/mm/slub.c b/mm/slub.c
index 68c02b2eecd90..5fc78b45aa66a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -434,7 +434,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 
 #ifdef CONFIG_SLUB_DEBUG
 static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
-static DEFINE_SPINLOCK(object_map_lock);
+static DEFINE_RAW_SPINLOCK(object_map_lock);
 
 /*
  * Determine a map of object in use on a page.
@@ -450,7 +450,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 
 	VM_BUG_ON(!irqs_disabled());
 
-	spin_lock(&object_map_lock);
+	raw_spin_lock(&object_map_lock);
 
 	bitmap_zero(object_map, page->objects);
 
@@ -463,7 +463,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 static void put_map(unsigned long *map) __releases(&object_map_lock)
 {
 	VM_BUG_ON(map != object_map);
-	spin_unlock(&object_map_lock);
+	raw_spin_unlock(&object_map_lock);
 }
 
 static inline unsigned int size_from_object(struct kmem_cache *s)
@@ -1213,7 +1213,7 @@ static noinline int free_debug_processing(
 	unsigned long flags;
 	int ret = 0;
 
-	spin_lock_irqsave(&n->list_lock, flags);
+	raw_spin_lock_irqsave(&n->list_lock, flags);
 	slab_lock(page);
 
 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
@@ -1248,7 +1248,7 @@ static noinline int free_debug_processing(
 			 bulk_cnt, cnt);
 
 	slab_unlock(page);
-	spin_unlock_irqrestore(&n->list_lock, flags);
+	raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	if (!ret)
 		slab_fix(s, "Object at 0x%p not freed", object);
 	return ret;
@@ -1500,6 +1500,12 @@ static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
 }
 #endif /* CONFIG_SLUB_DEBUG */
 
+struct slub_free_list {
+	raw_spinlock_t		lock;
+	struct list_head	list;
+};
+static DEFINE_PER_CPU(struct slub_free_list, slub_free_list);
+
 /*
  * Hooks for other subsystems that check memory allocations. In a typical
  * production configuration these hooks all should produce no code at all.
@@ -1743,10 +1749,18 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	void *start, *p, *next;
 	int idx;
 	bool shuffle;
+	bool enableirqs = false;
 
 	flags &= gfp_allowed_mask;
 
 	if (gfpflags_allow_blocking(flags))
+		enableirqs = true;
+
+#ifdef CONFIG_PREEMPT_RT
+	if (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND)
+		enableirqs = true;
+#endif
+	if (enableirqs)
 		local_irq_enable();
 
 	flags |= s->allocflags;
@@ -1805,7 +1819,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	page->frozen = 1;
 
 out:
-	if (gfpflags_allow_blocking(flags))
+	if (enableirqs)
 		local_irq_disable();
 	if (!page)
 		return NULL;
@@ -1848,6 +1862,16 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 	__free_pages(page, order);
 }
 
+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_slab(page->slab_cache, page);
+	}
+}
+
 static void rcu_free_slab(struct rcu_head *h)
 {
 	struct page *page = container_of(h, struct page, rcu_head);
@@ -1859,6 +1883,12 @@ static void free_slab(struct kmem_cache *s, struct page *page)
 {
 	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
 		call_rcu(&page->rcu_head, rcu_free_slab);
+	} else if (irqs_disabled()) {
+		struct slub_free_list *f = this_cpu_ptr(&slub_free_list);
+
+		raw_spin_lock(&f->lock);
+		list_add(&page->lru, &f->list);
+		raw_spin_unlock(&f->lock);
 	} else
 		__free_slab(s, page);
 }
@@ -1966,7 +1996,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 	if (!n || !n->nr_partial)
 		return NULL;
 
-	spin_lock(&n->list_lock);
+	raw_spin_lock(&n->list_lock);
 	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
 		void *t;
 
@@ -1991,7 +2021,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 			break;
 
 	}
-	spin_unlock(&n->list_lock);
+	raw_spin_unlock(&n->list_lock);
 	return object;
 }
 
@@ -2245,7 +2275,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 			 * that acquire_slab() will see a slab page that
 			 * is frozen
 			 */
-			spin_lock(&n->list_lock);
+			raw_spin_lock(&n->list_lock);
 		}
 	} else {
 		m = M_FULL;
@@ -2256,7 +2286,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 			 * slabs from diagnostic functions will not see
 			 * any frozen slabs.
 			 */
-			spin_lock(&n->list_lock);
+			raw_spin_lock(&n->list_lock);
 		}
 	}
 
@@ -2280,7 +2310,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 		goto redo;
 
 	if (lock)
-		spin_unlock(&n->list_lock);
+		raw_spin_unlock(&n->list_lock);
 
 	if (m == M_PARTIAL)
 		stat(s, tail);
@@ -2319,10 +2349,10 @@ static void unfreeze_partials(struct kmem_cache *s,
 		n2 = get_node(s, page_to_nid(page));
 		if (n != n2) {
 			if (n)
-				spin_unlock(&n->list_lock);
+				raw_spin_unlock(&n->list_lock);
 
 			n = n2;
-			spin_lock(&n->list_lock);
+			raw_spin_lock(&n->list_lock);
 		}
 
 		do {
@@ -2351,7 +2381,7 @@ static void unfreeze_partials(struct kmem_cache *s,
 	}
 
 	if (n)
-		spin_unlock(&n->list_lock);
+		raw_spin_unlock(&n->list_lock);
 
 	while (discard_page) {
 		page = discard_page;
@@ -2388,14 +2418,21 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
 			pobjects = oldpage->pobjects;
 			pages = oldpage->pages;
 			if (drain && pobjects > slub_cpu_partial(s)) {
+				struct slub_free_list *f;
 				unsigned long flags;
+				LIST_HEAD(tofree);
 				/*
 				 * partial array is full. Move the existing
 				 * set to the per node partial list.
 				 */
 				local_irq_save(flags);
 				unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
+				f = this_cpu_ptr(&slub_free_list);
+				raw_spin_lock(&f->lock);
+				list_splice_init(&f->list, &tofree);
+				raw_spin_unlock(&f->lock);
 				local_irq_restore(flags);
+				free_delayed(&tofree);
 				oldpage = NULL;
 				pobjects = 0;
 				pages = 0;
@@ -2463,7 +2500,19 @@ static bool has_cpu_slab(int cpu, void *info)
 
 static void flush_all(struct kmem_cache *s)
 {
+	LIST_HEAD(tofree);
+	int cpu;
+
 	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1);
+	for_each_online_cpu(cpu) {
+		struct slub_free_list *f;
+
+		f = &per_cpu(slub_free_list, cpu);
+		raw_spin_lock_irq(&f->lock);
+		list_splice_init(&f->list, &tofree);
+		raw_spin_unlock_irq(&f->lock);
+		free_delayed(&tofree);
+	}
 }
 
 /*
@@ -2518,10 +2567,10 @@ static unsigned long count_partial(struct kmem_cache_node *n,
 	unsigned long x = 0;
 	struct page *page;
 
-	spin_lock_irqsave(&n->list_lock, flags);
+	raw_spin_lock_irqsave(&n->list_lock, flags);
 	list_for_each_entry(page, &n->partial, slab_list)
 		x += get_count(page);
-	spin_unlock_irqrestore(&n->list_lock, flags);
+	raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	return x;
 }
 #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
@@ -2660,8 +2709,10 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page)
  * already disabled (which is the case for bulk allocation).
  */
 static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
-			  unsigned long addr, struct kmem_cache_cpu *c)
+			  unsigned long addr, struct kmem_cache_cpu *c,
+			  struct list_head *to_free)
 {
+	struct slub_free_list *f;
 	void *freelist;
 	struct page *page;
 
@@ -2727,6 +2778,13 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	VM_BUG_ON(!c->page->frozen);
 	c->freelist = get_freepointer(s, freelist);
 	c->tid = next_tid(c->tid);
+
+out:
+	f = this_cpu_ptr(&slub_free_list);
+	raw_spin_lock(&f->lock);
+	list_splice_init(&f->list, to_free);
+	raw_spin_unlock(&f->lock);
+
 	return freelist;
 
 new_slab:
@@ -2742,7 +2800,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	if (unlikely(!freelist)) {
 		slab_out_of_memory(s, gfpflags, node);
-		return NULL;
+		goto out;
 	}
 
 	page = c->page;
@@ -2755,7 +2813,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		goto new_slab;	/* Slab failed checks. Next slab needed */
 
 	deactivate_slab(s, page, get_freepointer(s, freelist), c);
-	return freelist;
+	goto out;
 }
 
 /*
@@ -2767,6 +2825,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 {
 	void *p;
 	unsigned long flags;
+	LIST_HEAD(tofree);
 
 	local_irq_save(flags);
 #ifdef CONFIG_PREEMPTION
@@ -2778,8 +2837,9 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	c = this_cpu_ptr(s->cpu_slab);
 #endif
 
-	p = ___slab_alloc(s, gfpflags, node, addr, c);
+	p = ___slab_alloc(s, gfpflags, node, addr, c, &tofree);
 	local_irq_restore(flags);
+	free_delayed(&tofree);
 	return p;
 }
 
@@ -2813,6 +2873,10 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	unsigned long tid;
 	struct obj_cgroup *objcg = NULL;
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP))
+		WARN_ON_ONCE(!preemptible() &&
+			     (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND));
+
 	s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags);
 	if (!s)
 		return NULL;
@@ -2979,7 +3043,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 
 	do {
 		if (unlikely(n)) {
-			spin_unlock_irqrestore(&n->list_lock, flags);
+			raw_spin_unlock_irqrestore(&n->list_lock, flags);
 			n = NULL;
 		}
 		prior = page->freelist;
@@ -3011,7 +3075,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 				 * Otherwise the list_lock will synchronize with
 				 * other processors updating the list of slabs.
 				 */
-				spin_lock_irqsave(&n->list_lock, flags);
+				raw_spin_lock_irqsave(&n->list_lock, flags);
 
 			}
 		}
@@ -3052,7 +3116,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 		add_partial(n, page, DEACTIVATE_TO_TAIL);
 		stat(s, FREE_ADD_PARTIAL);
 	}
-	spin_unlock_irqrestore(&n->list_lock, flags);
+	raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	return;
 
 slab_empty:
@@ -3067,7 +3131,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 		remove_full(s, n, page);
 	}
 
-	spin_unlock_irqrestore(&n->list_lock, flags);
+	raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	stat(s, FREE_SLAB);
 	discard_slab(s, page);
 }
@@ -3274,9 +3338,14 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 			  void **p)
 {
 	struct kmem_cache_cpu *c;
+	LIST_HEAD(to_free);
 	int i;
 	struct obj_cgroup *objcg = NULL;
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP))
+		WARN_ON_ONCE(!preemptible() &&
+			     (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND));
+
 	/* memcg and kmem_cache debug support */
 	s = slab_pre_alloc_hook(s, &objcg, size, flags);
 	if (unlikely(!s))
@@ -3307,7 +3376,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 			 * of re-populating per CPU c->freelist
 			 */
 			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
-					    _RET_IP_, c);
+					    _RET_IP_, c, &to_free);
 			if (unlikely(!p[i]))
 				goto error;
 
@@ -3322,6 +3391,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	}
 	c->tid = next_tid(c->tid);
 	local_irq_enable();
+	free_delayed(&to_free);
 
 	/* Clear memory outside IRQ disabled fastpath loop */
 	if (unlikely(slab_want_init_on_alloc(flags, s))) {
@@ -3336,6 +3406,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	return i;
 error:
 	local_irq_enable();
+	free_delayed(&to_free);
 	slab_post_alloc_hook(s, objcg, flags, i, p);
 	__kmem_cache_free_bulk(s, i, p);
 	return 0;
@@ -3471,7 +3542,7 @@ static void
 init_kmem_cache_node(struct kmem_cache_node *n)
 {
 	n->nr_partial = 0;
-	spin_lock_init(&n->list_lock);
+	raw_spin_lock_init(&n->list_lock);
 	INIT_LIST_HEAD(&n->partial);
 #ifdef CONFIG_SLUB_DEBUG
 	atomic_long_set(&n->nr_slabs, 0);
@@ -3872,7 +3943,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 	struct page *page, *h;
 
 	BUG_ON(irqs_disabled());
-	spin_lock_irq(&n->list_lock);
+	raw_spin_lock_irq(&n->list_lock);
 	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
 		if (!page->inuse) {
 			remove_partial(n, page);
@@ -3882,7 +3953,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 			  "Objects remaining in %s on __kmem_cache_shutdown()");
 		}
 	}
-	spin_unlock_irq(&n->list_lock);
+	raw_spin_unlock_irq(&n->list_lock);
 
 	list_for_each_entry_safe(page, h, &discard, slab_list)
 		discard_slab(s, page);
@@ -4153,7 +4224,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
 			INIT_LIST_HEAD(promote + i);
 
-		spin_lock_irqsave(&n->list_lock, flags);
+		raw_spin_lock_irqsave(&n->list_lock, flags);
 
 		/*
 		 * Build lists of slabs to discard or promote.
@@ -4184,7 +4255,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 		for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
 			list_splice(promote + i, &n->partial);
 
-		spin_unlock_irqrestore(&n->list_lock, flags);
+		raw_spin_unlock_irqrestore(&n->list_lock, flags);
 
 		/* Release empty slabs */
 		list_for_each_entry_safe(page, t, &discard, slab_list)
@@ -4359,6 +4430,12 @@ void __init kmem_cache_init(void)
 {
 	static __initdata struct kmem_cache boot_kmem_cache,
 		boot_kmem_cache_node;
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		raw_spin_lock_init(&per_cpu(slub_free_list, cpu).lock);
+		INIT_LIST_HEAD(&per_cpu(slub_free_list, cpu).list);
+	}
 
 	if (debug_guardpage_minorder())
 		slub_max_order = 0;
@@ -4546,7 +4623,7 @@ static int validate_slab_node(struct kmem_cache *s,
 	struct page *page;
 	unsigned long flags;
 
-	spin_lock_irqsave(&n->list_lock, flags);
+	raw_spin_lock_irqsave(&n->list_lock, flags);
 
 	list_for_each_entry(page, &n->partial, slab_list) {
 		validate_slab(s, page);
@@ -4568,7 +4645,7 @@ static int validate_slab_node(struct kmem_cache *s,
 		       s->name, count, atomic_long_read(&n->nr_slabs));
 
 out:
-	spin_unlock_irqrestore(&n->list_lock, flags);
+	raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	return count;
 }
 
@@ -4747,12 +4824,12 @@ static int list_locations(struct kmem_cache *s, char *buf,
 		if (!atomic_long_read(&n->nr_slabs))
 			continue;
 
-		spin_lock_irqsave(&n->list_lock, flags);
+		raw_spin_lock_irqsave(&n->list_lock, flags);
 		list_for_each_entry(page, &n->partial, slab_list)
 			process_slab(&t, s, page, alloc);
 		list_for_each_entry(page, &n->full, slab_list)
 			process_slab(&t, s, page, alloc);
-		spin_unlock_irqrestore(&n->list_lock, flags);
+		raw_spin_unlock_irqrestore(&n->list_lock, flags);
 	}
 
 	for (i = 0; i < t.count; i++) {
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index be4724b916b3e..994acb959d00d 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1544,7 +1544,7 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
 	struct vmap_block *vb;
 	struct vmap_area *va;
 	unsigned long vb_idx;
-	int node, err;
+	int node, err, cpu;
 	void *vaddr;
 
 	node = numa_node_id();
@@ -1581,11 +1581,12 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
 		return ERR_PTR(err);
 	}
 
-	vbq = &get_cpu_var(vmap_block_queue);
+	cpu = get_cpu_light();
+	vbq = this_cpu_ptr(&vmap_block_queue);
 	spin_lock(&vbq->lock);
 	list_add_tail_rcu(&vb->free_list, &vbq->free);
 	spin_unlock(&vbq->lock);
-	put_cpu_var(vmap_block_queue);
+	put_cpu_light();
 
 	return vaddr;
 }
@@ -1650,6 +1651,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
 	struct vmap_block *vb;
 	void *vaddr = NULL;
 	unsigned int order;
+	int cpu;
 
 	BUG_ON(offset_in_page(size));
 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
@@ -1664,7 +1666,8 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
 	order = get_order(size);
 
 	rcu_read_lock();
-	vbq = &get_cpu_var(vmap_block_queue);
+	cpu = get_cpu_light();
+	vbq = this_cpu_ptr(&vmap_block_queue);
 	list_for_each_entry_rcu(vb, &vbq->free, free_list) {
 		unsigned long pages_off;
 
@@ -1687,7 +1690,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
 		break;
 	}
 
-	put_cpu_var(vmap_block_queue);
+	put_cpu_light();
 	rcu_read_unlock();
 
 	/* Allocate new block if nothing was found */
diff --git a/mm/vmstat.c b/mm/vmstat.c
index e670f910cd2f3..8c47df8d9bcb6 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -321,6 +321,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 	long x;
 	long t;
 
+	preempt_disable_rt();
 	x = delta + __this_cpu_read(*p);
 
 	t = __this_cpu_read(pcp->stat_threshold);
@@ -330,6 +331,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 		x = 0;
 	}
 	__this_cpu_write(*p, x);
+	preempt_enable_rt();
 }
 EXPORT_SYMBOL(__mod_zone_page_state);
 
@@ -346,6 +348,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 		delta >>= PAGE_SHIFT;
 	}
 
+	preempt_disable_rt();
 	x = delta + __this_cpu_read(*p);
 
 	t = __this_cpu_read(pcp->stat_threshold);
@@ -355,6 +358,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 		x = 0;
 	}
 	__this_cpu_write(*p, x);
+	preempt_enable_rt();
 }
 EXPORT_SYMBOL(__mod_node_page_state);
 
@@ -387,6 +391,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 	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)) {
@@ -395,6 +400,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 		zone_page_state_add(v + overstep, zone, item);
 		__this_cpu_write(*p, -overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
@@ -405,6 +411,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 
 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 
+	preempt_disable_rt();
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
@@ -413,6 +420,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 		node_page_state_add(v + overstep, pgdat, item);
 		__this_cpu_write(*p, -overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
@@ -433,6 +441,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 	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)) {
@@ -441,6 +450,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 		zone_page_state_add(v - overstep, zone, item);
 		__this_cpu_write(*p, overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
@@ -451,6 +461,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 
 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 
+	preempt_disable_rt();
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
@@ -459,6 +470,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 		node_page_state_add(v - overstep, pgdat, item);
 		__this_cpu_write(*p, overstep);
 	}
+	preempt_enable_rt();
 }
 
 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
diff --git a/mm/workingset.c b/mm/workingset.c
index 92e66113a5779..29609352552fc 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -432,6 +432,8 @@ static struct list_lru shadow_nodes;
 
 void workingset_update_node(struct xa_node *node)
 {
+	struct address_space *mapping;
+
 	/*
 	 * Track non-empty nodes that contain only shadow entries;
 	 * unlink those that contain pages or are being freed.
@@ -440,7 +442,8 @@ void workingset_update_node(struct xa_node *node)
 	 * already where they should be. The list_empty() test is safe
 	 * as node->private_list is protected by the i_pages lock.
 	 */
-	VM_WARN_ON_ONCE(!irqs_disabled());  /* For __inc_lruvec_page_state */
+	mapping = container_of(node->array, struct address_space, i_pages);
+	lockdep_assert_held(&mapping->i_pages.xa_lock);
 
 	if (node->count && node->count == node->nr_values) {
 		if (list_empty(&node->private_list)) {
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index c36fdff9a3713..2cc22ee7b8945 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -57,6 +57,7 @@
 #include <linux/wait.h>
 #include <linux/pagemap.h>
 #include <linux/fs.h>
+#include <linux/local_lock.h>
 
 #define ZSPAGE_MAGIC	0x58
 
@@ -77,6 +78,20 @@
 
 #define ZS_HANDLE_SIZE (sizeof(unsigned long))
 
+#ifdef CONFIG_PREEMPT_RT
+
+struct zsmalloc_handle {
+	unsigned long addr;
+	struct mutex lock;
+};
+
+#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
+
+#else
+
+#define ZS_HANDLE_ALLOC_SIZE (sizeof(unsigned long))
+#endif
+
 /*
  * Object location (<PFN>, <obj_idx>) is encoded as
  * a single (unsigned long) handle value.
@@ -293,6 +308,7 @@ struct zspage {
 };
 
 struct mapping_area {
+	local_lock_t	lock;
 #ifdef CONFIG_ZSMALLOC_PGTABLE_MAPPING
 	struct vm_struct *vm; /* vm area for mapping object that span pages */
 #else
@@ -326,7 +342,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
 
 static int create_cache(struct zs_pool *pool)
 {
-	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
+	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_ALLOC_SIZE,
 					0, 0, NULL);
 	if (!pool->handle_cachep)
 		return 1;
@@ -350,10 +366,27 @@ static void destroy_cache(struct zs_pool *pool)
 
 static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
 {
-	return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
-			gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
+	void *p;
+
+	p = kmem_cache_alloc(pool->handle_cachep,
+			     gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
+#ifdef CONFIG_PREEMPT_RT
+	if (p) {
+		struct zsmalloc_handle *zh = p;
+
+		mutex_init(&zh->lock);
+	}
+#endif
+	return (unsigned long)p;
 }
 
+#ifdef CONFIG_PREEMPT_RT
+static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle)
+{
+	return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1));
+}
+#endif
+
 static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
 {
 	kmem_cache_free(pool->handle_cachep, (void *)handle);
@@ -372,12 +405,18 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
 
 static void record_obj(unsigned long handle, unsigned long obj)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	WRITE_ONCE(zh->addr, obj);
+#else
 	/*
 	 * lsb of @obj represents handle lock while other bits
 	 * represent object value the handle is pointing so
 	 * updating shouldn't do store tearing.
 	 */
 	WRITE_ONCE(*(unsigned long *)handle, obj);
+#endif
 }
 
 /* zpool driver */
@@ -459,7 +498,10 @@ MODULE_ALIAS("zpool-zsmalloc");
 #endif /* CONFIG_ZPOOL */
 
 /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
-static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
+static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = {
+	/* XXX remove this and use a spin_lock_t in pin_tag() */
+	.lock	= INIT_LOCAL_LOCK(lock),
+};
 
 static bool is_zspage_isolated(struct zspage *zspage)
 {
@@ -869,7 +911,13 @@ static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
 
 static unsigned long handle_to_obj(unsigned long handle)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	return zh->addr;
+#else
 	return *(unsigned long *)handle;
+#endif
 }
 
 static unsigned long obj_to_head(struct page *page, void *obj)
@@ -883,22 +931,46 @@ static unsigned long obj_to_head(struct page *page, void *obj)
 
 static inline int testpin_tag(unsigned long handle)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	return mutex_is_locked(&zh->lock);
+#else
 	return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
+#endif
 }
 
 static inline int trypin_tag(unsigned long handle)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	return mutex_trylock(&zh->lock);
+#else
 	return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
+#endif
 }
 
 static void pin_tag(unsigned long handle) __acquires(bitlock)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	return mutex_lock(&zh->lock);
+#else
 	bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
+#endif
 }
 
 static void unpin_tag(unsigned long handle) __releases(bitlock)
 {
+#ifdef CONFIG_PREEMPT_RT
+	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+
+	return mutex_unlock(&zh->lock);
+#else
 	bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
+#endif
 }
 
 static void reset_page(struct page *page)
@@ -1326,7 +1398,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 	class = pool->size_class[class_idx];
 	off = (class->size * obj_idx) & ~PAGE_MASK;
 
-	area = &get_cpu_var(zs_map_area);
+	local_lock(&zs_map_area.lock);
+	area = this_cpu_ptr(&zs_map_area);
 	area->vm_mm = mm;
 	if (off + class->size <= PAGE_SIZE) {
 		/* this object is contained entirely within a page */
@@ -1380,7 +1453,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 
 		__zs_unmap_object(area, pages, off, class->size);
 	}
-	put_cpu_var(zs_map_area);
+	local_unlock(&zs_map_area.lock);
 
 	migrate_read_unlock(zspage);
 	unpin_tag(handle);
diff --git a/mm/zswap.c b/mm/zswap.c
index fbb782924ccc5..78a20f7b00f2c 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -18,6 +18,7 @@
 #include <linux/highmem.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/local_lock.h>
 #include <linux/types.h>
 #include <linux/atomic.h>
 #include <linux/frontswap.h>
@@ -387,27 +388,35 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
 /*********************************
 * per-cpu code
 **********************************/
-static DEFINE_PER_CPU(u8 *, zswap_dstmem);
+struct zswap_comp {
+	/* Used for per-CPU dstmem and tfm */
+	local_lock_t lock;
+	u8 *dstmem;
+};
+
+static DEFINE_PER_CPU(struct zswap_comp, zswap_comp);
 
 static int zswap_dstmem_prepare(unsigned int cpu)
 {
+	struct zswap_comp *zcomp;
 	u8 *dst;
 
 	dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
 	if (!dst)
 		return -ENOMEM;
 
-	per_cpu(zswap_dstmem, cpu) = dst;
+	zcomp = per_cpu_ptr(&zswap_comp, cpu);
+	zcomp->dstmem = dst;
 	return 0;
 }
 
 static int zswap_dstmem_dead(unsigned int cpu)
 {
-	u8 *dst;
+	struct zswap_comp *zcomp;
 
-	dst = per_cpu(zswap_dstmem, cpu);
-	kfree(dst);
-	per_cpu(zswap_dstmem, cpu) = NULL;
+	zcomp = per_cpu_ptr(&zswap_comp, cpu);
+	kfree(zcomp->dstmem);
+	zcomp->dstmem = NULL;
 
 	return 0;
 }
@@ -919,10 +928,11 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
 		dlen = PAGE_SIZE;
 		src = (u8 *)zhdr + sizeof(struct zswap_header);
 		dst = kmap_atomic(page);
-		tfm = *get_cpu_ptr(entry->pool->tfm);
+		local_lock(&zswap_comp.lock);
+		tfm = *this_cpu_ptr(entry->pool->tfm);
 		ret = crypto_comp_decompress(tfm, src, entry->length,
 					     dst, &dlen);
-		put_cpu_ptr(entry->pool->tfm);
+		local_unlock(&zswap_comp.lock);
 		kunmap_atomic(dst);
 		BUG_ON(ret);
 		BUG_ON(dlen != PAGE_SIZE);
@@ -1074,12 +1084,12 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
 	}
 
 	/* compress */
-	dst = get_cpu_var(zswap_dstmem);
-	tfm = *get_cpu_ptr(entry->pool->tfm);
+	local_lock(&zswap_comp.lock);
+	dst = *this_cpu_ptr(&zswap_comp.dstmem);
+	tfm = *this_cpu_ptr(entry->pool->tfm);
 	src = kmap_atomic(page);
 	ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
 	kunmap_atomic(src);
-	put_cpu_ptr(entry->pool->tfm);
 	if (ret) {
 		ret = -EINVAL;
 		goto put_dstmem;
@@ -1103,7 +1113,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
 	memcpy(buf, &zhdr, hlen);
 	memcpy(buf + hlen, dst, dlen);
 	zpool_unmap_handle(entry->pool->zpool, handle);
-	put_cpu_var(zswap_dstmem);
+	local_unlock(&zswap_comp.lock);
 
 	/* populate entry */
 	entry->offset = offset;
@@ -1131,7 +1141,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
 	return 0;
 
 put_dstmem:
-	put_cpu_var(zswap_dstmem);
+	local_unlock(&zswap_comp.lock);
 	zswap_pool_put(entry->pool);
 freepage:
 	zswap_entry_cache_free(entry);
@@ -1176,9 +1186,10 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
 	if (zpool_evictable(entry->pool->zpool))
 		src += sizeof(struct zswap_header);
 	dst = kmap_atomic(page);
-	tfm = *get_cpu_ptr(entry->pool->tfm);
+	local_lock(&zswap_comp.lock);
+	tfm = *this_cpu_ptr(entry->pool->tfm);
 	ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
-	put_cpu_ptr(entry->pool->tfm);
+	local_unlock(&zswap_comp.lock);
 	kunmap_atomic(dst);
 	zpool_unmap_handle(entry->pool->zpool, entry->handle);
 	BUG_ON(ret);
diff --git a/net/Kconfig b/net/Kconfig
index 3831206977a17..81ae878ae553d 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -282,7 +282,7 @@ config CGROUP_NET_CLASSID
 
 config NET_RX_BUSY_POLL
 	bool
-	default y
+	default y if !PREEMPT_RT
 
 config BQL
 	bool
diff --git a/net/core/dev.c b/net/core/dev.c
index b9c6f31ae96eb..9abf885c25d98 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -219,14 +219,14 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
 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
 }
 
@@ -3034,6 +3034,7 @@ static void __netif_reschedule(struct Qdisc *q)
 	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)
@@ -3096,6 +3097,7 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
 	__this_cpu_write(softnet_data.completion_queue, skb);
 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(__dev_kfree_skb_irq);
 
@@ -3762,7 +3764,11 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 	 * This permits qdisc->running owner to get the lock more
 	 * often and dequeue packets faster.
 	 */
+#ifdef CONFIG_PREEMPT_RT
+	contended = true;
+#else
 	contended = qdisc_is_running(q);
+#endif
 	if (unlikely(contended))
 		spin_lock(&q->busylock);
 
@@ -4558,6 +4564,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
 	rps_unlock(sd);
 
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 
 	atomic_long_inc(&skb->dev->rx_dropped);
 	kfree_skb(skb);
@@ -4773,7 +4780,7 @@ static int netif_rx_internal(struct sk_buff *skb)
 		struct rps_dev_flow voidflow, *rflow = &voidflow;
 		int cpu;
 
-		preempt_disable();
+		migrate_disable();
 		rcu_read_lock();
 
 		cpu = get_rps_cpu(skb->dev, skb, &rflow);
@@ -4783,14 +4790,14 @@ static int netif_rx_internal(struct sk_buff *skb)
 		ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
 
 		rcu_read_unlock();
-		preempt_enable();
+		migrate_enable();
 	} else
 #endif
 	{
 		unsigned int qtail;
 
-		ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
-		put_cpu();
+		ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail);
+		put_cpu_light();
 	}
 	return ret;
 }
@@ -4829,11 +4836,9 @@ int netif_rx_ni(struct sk_buff *skb)
 
 	trace_netif_rx_ni_entry(skb);
 
-	preempt_disable();
+	local_bh_disable();
 	err = netif_rx_internal(skb);
-	if (local_softirq_pending())
-		do_softirq();
-	preempt_enable();
+	local_bh_enable();
 	trace_netif_rx_ni_exit(err);
 
 	return err;
@@ -6202,12 +6207,14 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd)
 		sd->rps_ipi_list = NULL;
 
 		local_irq_enable();
+		preempt_check_resched_rt();
 
 		/* Send pending IPI's to kick RPS processing on remote cpus. */
 		net_rps_send_ipi(remsd);
 	} else
 #endif
 		local_irq_enable();
+	preempt_check_resched_rt();
 }
 
 static bool sd_has_rps_ipi_waiting(struct softnet_data *sd)
@@ -6285,6 +6292,7 @@ void __napi_schedule(struct napi_struct *n)
 	local_irq_save(flags);
 	____napi_schedule(this_cpu_ptr(&softnet_data), n);
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 EXPORT_SYMBOL(__napi_schedule);
 
@@ -10630,6 +10638,7 @@ static int dev_cpu_dead(unsigned int oldcpu)
 
 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
 	local_irq_enable();
+	preempt_check_resched_rt();
 
 #ifdef CONFIG_RPS
 	remsd = oldsd->rps_ipi_list;
@@ -10959,7 +10968,7 @@ static int __init net_dev_init(void)
 
 		INIT_WORK(flush, flush_backlog);
 
-		skb_queue_head_init(&sd->input_pkt_queue);
+		skb_queue_head_init_raw(&sd->input_pkt_queue);
 		skb_queue_head_init(&sd->process_queue);
 #ifdef CONFIG_XFRM_OFFLOAD
 		skb_queue_head_init(&sd->xfrm_backlog);
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 80dbf2f4016e2..698b02dfeaaf7 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -42,7 +42,7 @@
 struct net_rate_estimator {
 	struct gnet_stats_basic_packed	*bstats;
 	spinlock_t		*stats_lock;
-	seqcount_t		*running;
+	net_seqlock_t		*running;
 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
 	u8			ewma_log;
 	u8			intvl_log; /* period : (250ms << intvl_log) */
@@ -125,7 +125,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
 		      spinlock_t *lock,
-		      seqcount_t *running,
+		      net_seqlock_t *running,
 		      struct nlattr *opt)
 {
 	struct gnet_estimator *parm = nla_data(opt);
@@ -223,7 +223,7 @@ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **rate_est,
 			  spinlock_t *lock,
-			  seqcount_t *running, struct nlattr *opt)
+			  net_seqlock_t *running, struct nlattr *opt)
 {
 	return gen_new_estimator(bstats, cpu_bstats, rate_est,
 				 lock, running, opt);
diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
index e491b083b3485..ef432cea2e105 100644
--- a/net/core/gen_stats.c
+++ b/net/core/gen_stats.c
@@ -137,7 +137,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
 }
 
 void
-__gnet_stats_copy_basic(const seqcount_t *running,
+__gnet_stats_copy_basic(net_seqlock_t *running,
 			struct gnet_stats_basic_packed *bstats,
 			struct gnet_stats_basic_cpu __percpu *cpu,
 			struct gnet_stats_basic_packed *b)
@@ -150,15 +150,15 @@ __gnet_stats_copy_basic(const seqcount_t *running,
 	}
 	do {
 		if (running)
-			seq = read_seqcount_begin(running);
+			seq = net_seq_begin(running);
 		bstats->bytes = b->bytes;
 		bstats->packets = b->packets;
-	} while (running && read_seqcount_retry(running, seq));
+	} while (running && net_seq_retry(running, seq));
 }
 EXPORT_SYMBOL(__gnet_stats_copy_basic);
 
 static int
-___gnet_stats_copy_basic(const seqcount_t *running,
+___gnet_stats_copy_basic(net_seqlock_t *running,
 			 struct gnet_dump *d,
 			 struct gnet_stats_basic_cpu __percpu *cpu,
 			 struct gnet_stats_basic_packed *b,
@@ -204,7 +204,7 @@ ___gnet_stats_copy_basic(const seqcount_t *running,
  * if the room in the socket buffer was not sufficient.
  */
 int
-gnet_stats_copy_basic(const seqcount_t *running,
+gnet_stats_copy_basic(net_seqlock_t *running,
 		      struct gnet_dump *d,
 		      struct gnet_stats_basic_cpu __percpu *cpu,
 		      struct gnet_stats_basic_packed *b)
@@ -228,7 +228,7 @@ EXPORT_SYMBOL(gnet_stats_copy_basic);
  * if the room in the socket buffer was not sufficient.
  */
 int
-gnet_stats_copy_basic_hw(const seqcount_t *running,
+gnet_stats_copy_basic_hw(net_seqlock_t *running,
 			 struct gnet_dump *d,
 			 struct gnet_stats_basic_cpu __percpu *cpu,
 			 struct gnet_stats_basic_packed *b)
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 2a76a2f5ed88c..1542f1a5a31c8 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1257,7 +1257,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
 		rcu_assign_pointer(sch->stab, stab);
 	}
 	if (tca[TCA_RATE]) {
-		seqcount_t *running;
+		net_seqlock_t *running;
 
 		err = -EOPNOTSUPP;
 		if (sch->flags & TCQ_F_MQROOT) {
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 265a61d011dfa..b502be4c4cd50 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -553,7 +553,11 @@ struct Qdisc noop_qdisc = {
 	.ops		=	&noop_qdisc_ops,
 	.q.lock		=	__SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
 	.dev_queue	=	&noop_netdev_queue,
+#ifdef CONFIG_PREEMPT_RT
+	.running	=	__SEQLOCK_UNLOCKED(noop_qdisc.running),
+#else
 	.running	=	SEQCNT_ZERO(noop_qdisc.running),
+#endif
 	.busylock	=	__SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
 	.gso_skb = {
 		.next = (struct sk_buff *)&noop_qdisc.gso_skb,
@@ -858,9 +862,15 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 	lockdep_set_class(&sch->busylock,
 			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
 
+#ifdef CONFIG_PREEMPT_RT
+	seqlock_init(&sch->running);
+	lockdep_set_class(&sch->running.lock,
+			  dev->qdisc_running_key ?: &qdisc_running_key);
+#else
 	seqcount_init(&sch->running);
 	lockdep_set_class(&sch->running,
 			  dev->qdisc_running_key ?: &qdisc_running_key);
+#endif
 
 	sch->ops = ops;
 	sch->flags = ops->static_flags;
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 43cf8dbde898b..d5516102491b7 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -422,7 +422,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
 		return;
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
 
 	atomic_long_inc(&pool->sp_stats.packets);
@@ -446,7 +446,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 	rqstp = NULL;
 out_unlock:
 	rcu_read_unlock();
-	put_cpu();
+	put_cpu_light();
 	trace_svc_xprt_do_enqueue(xprt, rqstp);
 }
 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 69520ad3d83bf..d16d4bbc86ab1 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -44,7 +44,7 @@ static void xfrm_state_gc_task(struct work_struct *work);
  */
 
 static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024;
-static __read_mostly seqcount_t xfrm_state_hash_generation = SEQCNT_ZERO(xfrm_state_hash_generation);
+static __read_mostly seqcount_spinlock_t xfrm_state_hash_generation;
 static struct kmem_cache *xfrm_state_cache __ro_after_init;
 
 static DECLARE_WORK(xfrm_state_gc_work, xfrm_state_gc_task);
@@ -139,6 +139,11 @@ static void xfrm_hash_resize(struct work_struct *work)
 		return;
 	}
 
+	/* XXX - the locking which protects the sequence counter appears
+	 * to be broken here. The sequence counter is global, but the
+	 * spinlock used for the sequence counter write serialization is
+	 * per network namespace...
+	 */
 	spin_lock_bh(&net->xfrm.xfrm_state_lock);
 	write_seqcount_begin(&xfrm_state_hash_generation);
 
@@ -2557,6 +2562,8 @@ int __net_init xfrm_state_init(struct net *net)
 	net->xfrm.state_num = 0;
 	INIT_WORK(&net->xfrm.state_hash_work, xfrm_hash_resize);
 	spin_lock_init(&net->xfrm.xfrm_state_lock);
+	seqcount_spinlock_init(&xfrm_state_hash_generation,
+			       &net->xfrm.xfrm_state_lock);
 	return 0;
 
 out_byspi:
