[PATCH] x86/locking: Use sfence for wmb() if SSE is available
Yao Zi <[email protected]>
| Newsgroups | org.kernel.vger.stable,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
When adding cc clobber to wmb()'s definition, the alternative()
condition to use sfence was incorrectly raised from X86_FEATURE_XMM to
X86_FEATURE_XMM2.
Restore the correct constraint for potential better performance on
machines without SSE2.
Fixes: bd922477d935 ("locking/x86: Add cc clobber for ADDL")
Signed-off-by: Yao Zi <[email protected]>
Cc: [email protected]
---
arch/x86/include/asm/barrier.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index b0096b5645a9..e0e59da15748 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -17,7 +17,7 @@
#define rmb() asm volatile(ALTERNATIVE("lock addl $0,-4(%%esp)", "lfence", \
X86_FEATURE_XMM2) ::: "memory", "cc")
#define wmb() asm volatile(ALTERNATIVE("lock addl $0,-4(%%esp)", "sfence", \
- X86_FEATURE_XMM2) ::: "memory", "cc")
+ X86_FEATURE_XMM) ::: "memory", "cc")
#else
#define __mb() asm volatile("mfence":::"memory")
#define __rmb() asm volatile("lfence":::"memory")
--
2.54.0