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-rw-r--r--arch/x86/include/asm/bitops.h19
1 files changed, 2 insertions, 17 deletions
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index b2af6645ea7..6dfd0195bb5 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -347,19 +347,6 @@ static int test_bit(int nr, const volatile unsigned long *addr);
? constant_test_bit((nr), (addr)) \
: variable_test_bit((nr), (addr)))
-#if (defined(CONFIG_X86_GENERIC) || defined(CONFIG_GENERIC_CPU)) \
- && !defined(CONFIG_CC_OPTIMIZE_FOR_SIZE)
-/*
- * Since BSF and TZCNT have sufficiently similar semantics for the purposes
- * for which we use them here, BMI-capable hardware will decode the prefixed
- * variant as 'tzcnt ...' and may execute that faster than 'bsf ...', while
- * older hardware will ignore the REP prefix and decode it as 'bsf ...'.
- */
-# define BSF_PREFIX "rep;"
-#else
-# define BSF_PREFIX
-#endif
-
/**
* __ffs - find first set bit in word
* @word: The word to search
@@ -368,7 +355,7 @@ static int test_bit(int nr, const volatile unsigned long *addr);
*/
static inline unsigned long __ffs(unsigned long word)
{
- asm(BSF_PREFIX "bsf %1,%0"
+ asm("rep; bsf %1,%0"
: "=r" (word)
: "rm" (word));
return word;
@@ -382,14 +369,12 @@ static inline unsigned long __ffs(unsigned long word)
*/
static inline unsigned long ffz(unsigned long word)
{
- asm(BSF_PREFIX "bsf %1,%0"
+ asm("rep; bsf %1,%0"
: "=r" (word)
: "r" (~word));
return word;
}
-#undef BSF_PREFIX
-
/*
* __fls: find last set bit in word
* @word: The word to search