diff options
| author | Nick Piggin <npiggin@suse.de> | 2007-10-13 03:06:55 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-12 18:41:21 -0700 |
| commit | 4071c718555d955a35e9651f77086096ad87d498 (patch) | |
| tree | 5189a9995143892a8ef7ecfc04c11c1d546bc21b | |
| parent | df1bdc0667eb3132fe60b3562347ca9133694ee0 (diff) | |
x86: fix IO write barrier
wmb() on x86 must always include a barrier, because stores can go out of
order in many cases when dealing with devices (eg. WC memory).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/asm-x86/system_32.h | 15 | ||||
| -rw-r--r-- | include/asm-x86/system_64.h | 6 |
2 files changed, 7 insertions, 14 deletions
diff --git a/include/asm-x86/system_32.h b/include/asm-x86/system_32.h index d69ba937e092..8b15bd3057c9 100644 --- a/include/asm-x86/system_32.h +++ b/include/asm-x86/system_32.h @@ -216,6 +216,7 @@ static inline unsigned long get_limit(unsigned long segment) #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) +#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) /** * read_barrier_depends - Flush all pending reads that subsequents reads @@ -271,18 +272,14 @@ static inline unsigned long get_limit(unsigned long segment) #define read_barrier_depends() do { } while(0) -#ifdef CONFIG_X86_OOSTORE -/* Actually there are no OOO store capable CPUs for now that do SSE, - but make it already an possibility. */ -#define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) -#else -#define wmb() __asm__ __volatile__ ("": : :"memory") -#endif - #ifdef CONFIG_SMP #define smp_mb() mb() #define smp_rmb() rmb() -#define smp_wmb() wmb() +#ifdef CONFIG_X86_OOSTORE +# define smp_wmb() wmb() +#else +# define smp_wmb() barrier() +#endif #define smp_read_barrier_depends() read_barrier_depends() #define set_mb(var, value) do { (void) xchg(&var, value); } while (0) #else diff --git a/include/asm-x86/system_64.h b/include/asm-x86/system_64.h index 02175aa1d16a..eff730b11926 100644 --- a/include/asm-x86/system_64.h +++ b/include/asm-x86/system_64.h @@ -159,12 +159,8 @@ static inline void write_cr8(unsigned long val) */ #define mb() asm volatile("mfence":::"memory") #define rmb() asm volatile("lfence":::"memory") - -#ifdef CONFIG_UNORDERED_IO #define wmb() asm volatile("sfence" ::: "memory") -#else -#define wmb() asm volatile("" ::: "memory") -#endif + #define read_barrier_depends() do {} while(0) #define set_mb(var, value) do { (void) xchg(&var, value); } while (0) |