Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core locking changes from Ingo Molnar:
 - futex performance increases: larger hashes, smarter wakeups
 - mutex debugging improvements
 - lots of SMP ordering documentation updates
 - introduce the smp_load_acquire(), smp_store_release() primitives.
   (There are WIP patches that make use of them - not yet merged)
 - lockdep micro-optimizations
 - lockdep improvement: better cover IRQ contexts
 - liblockdep at last. We'll continue to monitor how useful this is

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  futexes: Fix futex_hashsize initialization
  arch: Re-sort some Kbuild files to hopefully help avoid some conflicts
  futexes: Avoid taking the hb->lock if there's nothing to wake up
  futexes: Document multiprocessor ordering guarantees
  futexes: Increase hash table size for better performance
  futexes: Clean up various details
  arch: Introduce smp_load_acquire(), smp_store_release()
  arch: Clean up asm/barrier.h implementations using asm-generic/barrier.h
  arch: Move smp_mb__{before,after}_atomic_{inc,dec}.h into asm/atomic.h
  locking/doc: Rename LOCK/UNLOCK to ACQUIRE/RELEASE
  mutexes: Give more informative mutex warning in the !lock->owner case
  powerpc: Full barrier for smp_mb__after_unlock_lock()
  rcu: Apply smp_mb__after_unlock_lock() to preserve grace periods
  Documentation/memory-barriers.txt: Downgrade UNLOCK+BLOCK
  locking: Add an smp_mb__after_unlock_lock() for UNLOCK+BLOCK barrier
  Documentation/memory-barriers.txt: Document ACCESS_ONCE()
  Documentation/memory-barriers.txt: Prohibit speculative writes
  Documentation/memory-barriers.txt: Add long atomic examples to memory-barriers.txt
  Documentation/memory-barriers.txt: Add needed ACCESS_ONCE() calls to memory-barriers.txt
  Revert "smp/cpumask: Make CONFIG_CPUMASK_OFFSTACK=y usable without debug dependency"
  ...

1 files changed, 50 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
index d4a63338a53..78e20ba8806 100644
--- a/arch/arm64/include/asm/barrier.h
+++ b/arch/arm64/include/asm/barrier.h
@@ -35,10 +35,60 @@
 #define smp_mb()	barrier()
 #define smp_rmb()	barrier()
 #define smp_wmb()	barrier()
+
+#define smp_store_release(p, v)						\
+do {									\
+	compiletime_assert_atomic_type(*p);				\
+	smp_mb();							\
+	ACCESS_ONCE(*p) = (v);						\
+} while (0)
+
+#define smp_load_acquire(p)						\
+({									\
+	typeof(*p) ___p1 = ACCESS_ONCE(*p);				\
+	compiletime_assert_atomic_type(*p);				\
+	smp_mb();							\
+	___p1;								\
+})
+
 #else
+
 #define smp_mb()	asm volatile("dmb ish" : : : "memory")
 #define smp_rmb()	asm volatile("dmb ishld" : : : "memory")
 #define smp_wmb()	asm volatile("dmb ishst" : : : "memory")
+
+#define smp_store_release(p, v)						\
+do {									\
+	compiletime_assert_atomic_type(*p);				\
+	switch (sizeof(*p)) {						\
+	case 4:								\
+		asm volatile ("stlr %w1, %0"				\
+				: "=Q" (*p) : "r" (v) : "memory");	\
+		break;							\
+	case 8:								\
+		asm volatile ("stlr %1, %0"				\
+				: "=Q" (*p) : "r" (v) : "memory");	\
+		break;							\
+	}								\
+} while (0)
+
+#define smp_load_acquire(p)						\
+({									\
+	typeof(*p) ___p1;						\
+	compiletime_assert_atomic_type(*p);				\
+	switch (sizeof(*p)) {						\
+	case 4:								\
+		asm volatile ("ldar %w0, %1"				\
+			: "=r" (___p1) : "Q" (*p) : "memory");		\
+		break;							\
+	case 8:								\
+		asm volatile ("ldar %0, %1"				\
+			: "=r" (___p1) : "Q" (*p) : "memory");		\
+		break;							\
+	}								\
+	___p1;								\
+})
+
 #endif
 
 #define read_barrier_depends()		do { } while(0)