diff options
Diffstat (limited to 'kernel/arch/arm/include/asm/sync_bitops.h')
| -rw-r--r-- | kernel/arch/arm/include/asm/sync_bitops.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/kernel/arch/arm/include/asm/sync_bitops.h b/kernel/arch/arm/include/asm/sync_bitops.h new file mode 100644 index 000000000..9732b8e11 --- /dev/null +++ b/kernel/arch/arm/include/asm/sync_bitops.h @@ -0,0 +1,26 @@ +#ifndef __ASM_SYNC_BITOPS_H__ +#define __ASM_SYNC_BITOPS_H__ + +#include <asm/bitops.h> + +/* sync_bitops functions are equivalent to the SMP implementation of the + * original functions, independently from CONFIG_SMP being defined. + * + * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But + * under Xen you might be communicating with a completely external entity + * who might be on another CPU (e.g. two uniprocessor guests communicating + * via event channels and grant tables). So we need a variant of the bit + * ops which are SMP safe even on a UP kernel. + */ + +#define sync_set_bit(nr, p) _set_bit(nr, p) +#define sync_clear_bit(nr, p) _clear_bit(nr, p) +#define sync_change_bit(nr, p) _change_bit(nr, p) +#define sync_test_and_set_bit(nr, p) _test_and_set_bit(nr, p) +#define sync_test_and_clear_bit(nr, p) _test_and_clear_bit(nr, p) +#define sync_test_and_change_bit(nr, p) _test_and_change_bit(nr, p) +#define sync_test_bit(nr, addr) test_bit(nr, addr) +#define sync_cmpxchg cmpxchg + + +#endif |