diff options
Diffstat (limited to 'libc/arch-x86/bionic/atomics_x86.c')
| -rw-r--r-- | libc/arch-x86/bionic/atomics_x86.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/libc/arch-x86/bionic/atomics_x86.c b/libc/arch-x86/bionic/atomics_x86.c index b7b20e6..d6e3247 100644 --- a/libc/arch-x86/bionic/atomics_x86.c +++ b/libc/arch-x86/bionic/atomics_x86.c @@ -60,6 +60,43 @@ int __futex_wake(volatile void *ftx, int count) return ret; } +/* Private futexes belong to a single address space and cannot be + * shared among processes. They are however significantly faster to + * operate than standard futexes. + */ +#define FUTEX_PRIVATE_FLAG 128 +#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT|FUTEX_PRIVATE_FLAG) +#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE|FUTEX_PRIVATE_FLAG) + +int __futex_wait_private(volatile void *ftx, int val) +{ + int ret; + asm volatile ( + "int $0x80;" + : "=a" (ret) + : "0" (FUTEX_SYSCALL), + "b" (ftx), + "c" (FUTEX_WAIT_PRIVATE), + "d" (val), + "S" (0) + ); + return ret; +} + +int __futex_wake_private(volatile void *ftx, int count) +{ + int ret; + asm volatile ( + "int $0x80;" + : "=a" (ret) + : "0" (FUTEX_SYSCALL), + "b" (ftx), + "c" (FUTEX_WAKE_PRIVATE), + "d" (count) + ); + return ret; +} + int __atomic_cmpxchg(int old, int new, volatile int* addr) { int xchg; asm volatile ( |