diff options
| author | Will Deacon <will.deacon@arm.com> | 2015-08-06 17:54:44 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-08-12 11:59:10 +0200 |
| commit | 0ca326de7aa9cb253db9c1a3eb3f0487c8dbf912 (patch) | |
| tree | 2964ef144f8b873c9af610577b4e3c92c0af9ac8 /arch/arm/include/asm/cmpxchg.h | |
| parent | cd074aea9261784e44f292e1132830ec221802c6 (diff) | |
locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations
By defining our SMP atomics in terms of relaxed operations, we gain
a small reduction in code size and have acquire/release/fence variants
generated automatically by the core code.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1438880084-18856-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arm/include/asm/cmpxchg.h')
| -rw-r--r-- | arch/arm/include/asm/cmpxchg.h | 47 |
1 files changed, 8 insertions, 39 deletions
diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h index 1692a05d3207..916a2744d5c6 100644 --- a/arch/arm/include/asm/cmpxchg.h +++ b/arch/arm/include/asm/cmpxchg.h @@ -35,7 +35,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size unsigned int tmp; #endif - smp_mb(); prefetchw((const void *)ptr); switch (size) { @@ -98,12 +97,11 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size __bad_xchg(ptr, size), ret = 0; break; } - smp_mb(); return ret; } -#define xchg(ptr, x) ({ \ +#define xchg_relaxed(ptr, x) ({ \ (__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), \ sizeof(*(ptr))); \ }) @@ -117,6 +115,8 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size #error "SMP is not supported on this platform" #endif +#define xchg xchg_relaxed + /* * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make * them available. @@ -194,23 +194,11 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, return oldval; } -static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old, - unsigned long new, int size) -{ - unsigned long ret; - - smp_mb(); - ret = __cmpxchg(ptr, old, new, size); - smp_mb(); - - return ret; -} - -#define cmpxchg(ptr,o,n) ({ \ - (__typeof__(*(ptr)))__cmpxchg_mb((ptr), \ - (unsigned long)(o), \ - (unsigned long)(n), \ - sizeof(*(ptr))); \ +#define cmpxchg_relaxed(ptr,o,n) ({ \ + (__typeof__(*(ptr)))__cmpxchg((ptr), \ + (unsigned long)(o), \ + (unsigned long)(n), \ + sizeof(*(ptr))); \ }) static inline unsigned long __cmpxchg_local(volatile void *ptr, @@ -273,25 +261,6 @@ static inline unsigned long long __cmpxchg64(unsigned long long *ptr, #define cmpxchg64_local(ptr, o, n) cmpxchg64_relaxed((ptr), (o), (n)) -static inline unsigned long long __cmpxchg64_mb(unsigned long long *ptr, - unsigned long long old, - unsigned long long new) -{ - unsigned long long ret; - - smp_mb(); - ret = __cmpxchg64(ptr, old, new); - smp_mb(); - - return ret; -} - -#define cmpxchg64(ptr, o, n) ({ \ - (__typeof__(*(ptr)))__cmpxchg64_mb((ptr), \ - (unsigned long long)(o), \ - (unsigned long long)(n)); \ -}) - #endif /* __LINUX_ARM_ARCH__ >= 6 */ #endif /* __ASM_ARM_CMPXCHG_H */ |