From d00a569284b1340c16fe2c148099e077ea09ebc9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 13 Mar 2014 19:00:35 +0100 Subject: arch,x86: Convert smp_mb__*() x86 is strongly ordered and all its atomic ops imply a full barrier. Implement the two new primitives as the old ones were. Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-knswsr5mldkr0w1lrdxvc81w@git.kernel.org Cc: Dave Jones Cc: Jesse Brandeburg Cc: Linus Torvalds Cc: Michel Lespinasse Cc: Will Deacon Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/atomic.h | 7 +------ arch/x86/include/asm/barrier.h | 4 ++++ arch/x86/include/asm/bitops.h | 6 ++---- arch/x86/include/asm/sync_bitops.h | 2 +- arch/x86/kernel/apic/hw_nmi.c | 2 +- 5 files changed, 9 insertions(+), 12 deletions(-) diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index b17f4f48ecd7..6dd1c7dd0473 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -7,6 +7,7 @@ #include #include #include +#include /* * Atomic operations that C can't guarantee us. Useful for @@ -243,12 +244,6 @@ static inline void atomic_or_long(unsigned long *v1, unsigned long v2) : : "r" ((unsigned)(mask)), "m" (*(addr)) \ : "memory") -/* Atomic operations are already serializing on x86 */ -#define smp_mb__before_atomic_dec() barrier() -#define smp_mb__after_atomic_dec() barrier() -#define smp_mb__before_atomic_inc() barrier() -#define smp_mb__after_atomic_inc() barrier() - #ifdef CONFIG_X86_32 # include #else diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h index 69bbb4845020..5c7198cca5ed 100644 --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -137,6 +137,10 @@ do { \ #endif +/* Atomic operations are already serializing on x86 */ +#define smp_mb__before_atomic() barrier() +#define smp_mb__after_atomic() barrier() + /* * Stop RDTSC speculation. This is needed when you need to use RDTSC * (or get_cycles or vread that possibly accesses the TSC) in a defined diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index 9fc1af74dc83..afcd35d331de 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -15,6 +15,7 @@ #include #include #include +#include #if BITS_PER_LONG == 32 # define _BITOPS_LONG_SHIFT 5 @@ -102,7 +103,7 @@ static inline void __set_bit(long nr, volatile unsigned long *addr) * * clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, - * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() + * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic() * in order to ensure changes are visible on other processors. */ static __always_inline void @@ -156,9 +157,6 @@ static inline void __clear_bit_unlock(long nr, volatile unsigned long *addr) __clear_bit(nr, addr); } -#define smp_mb__before_clear_bit() barrier() -#define smp_mb__after_clear_bit() barrier() - /** * __change_bit - Toggle a bit in memory * @nr: the bit to change diff --git a/arch/x86/include/asm/sync_bitops.h b/arch/x86/include/asm/sync_bitops.h index 05af3b31d522..f28a24b51dc7 100644 --- a/arch/x86/include/asm/sync_bitops.h +++ b/arch/x86/include/asm/sync_bitops.h @@ -41,7 +41,7 @@ static inline void sync_set_bit(long nr, volatile unsigned long *addr) * * sync_clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, - * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() + * you should call smp_mb__before_atomic() and/or smp_mb__after_atomic() * in order to ensure changes are visible on other processors. */ static inline void sync_clear_bit(long nr, volatile unsigned long *addr) diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c index a698d7165c96..eab67047dec3 100644 --- a/arch/x86/kernel/apic/hw_nmi.c +++ b/arch/x86/kernel/apic/hw_nmi.c @@ -57,7 +57,7 @@ void arch_trigger_all_cpu_backtrace(void) } clear_bit(0, &backtrace_flag); - smp_mb__after_clear_bit(); + smp_mb__after_atomic(); } static int __kprobes -- cgit