diff options
Diffstat (limited to 'xen/include/asm-x86/bitops.h')
| -rw-r--r-- | xen/include/asm-x86/bitops.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/xen/include/asm-x86/bitops.h b/xen/include/asm-x86/bitops.h index b2ee953361..b9fd2557d0 100644 --- a/xen/include/asm-x86/bitops.h +++ b/xen/include/asm-x86/bitops.h @@ -75,6 +75,24 @@ static __inline__ void clear_bit(int nr, volatile void * addr) :"=m" (ADDR) :"dIr" (nr)); } + +/** + * __clear_bit - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + * + * Unlike clear_bit(), this function is non-atomic and may be reordered. + * If it's called on the same region of memory simultaneously, the effect + * may be that only one operation succeeds. + */ +static __inline__ void __clear_bit(int nr, volatile void * addr) +{ + __asm__( + "btrl %1,%0" + :"=m" (ADDR) + :"dIr" (nr)); +} + #define smp_mb__before_clear_bit() barrier() #define smp_mb__after_clear_bit() barrier() |