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| author |   kettenis <kettenis@openbsd.org> | 2014-09-11 20:32:16 +0000 |
|---|---|---|
| committer | kettenis <kettenis@openbsd.org> | 2014-09-11 20:32:16 +0000 |
| commit | cd73abdf1278d14fd2048d89484411ccda38909a (patch) | |
| tree | f6408499cba86db0c1c1faad1cd6c3ecd6877f86 | |
| parent | Install files that moved from etc to base during "make build" (diff) | |
| download | wireguard-openbsd-cd73abdf1278d14fd2048d89484411ccda38909a.tar.xz wireguard-openbsd-cd73abdf1278d14fd2048d89484411ccda38909a.zip | |
mplement membar(9) API for i386.
ok matthew@, guenther@
| -rw-r--r-- | sys/arch/i386/include/atomic.h | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/sys/arch/i386/include/atomic.h b/sys/arch/i386/include/atomic.h index 7791af060ca..cbaf0fb8612 100644 --- a/sys/arch/i386/include/atomic.h +++ b/sys/arch/i386/include/atomic.h @@ -1,4 +1,4 @@ -/* $OpenBSD: atomic.h,v 1.12 2014/03/29 18:09:29 guenther Exp $ */ +/* $OpenBSD: atomic.h,v 1.13 2014/09/11 20:32:16 kettenis Exp $ */ /* $NetBSD: atomic.h,v 1.1.2.2 2000/02/21 18:54:07 sommerfeld Exp $ */ /*- @@ -110,6 +110,32 @@ i386_atomic_cas_int32(volatile int32_t *ptr, int32_t expect, int32_t set) return (res); } +/* + * The IA-32 architecture is rather strongly ordered. When accessing + * normal write-back cachable memory, only reads may be reordered with + * older writes to different locations. There are a few instructions + * (clfush, non-temporal move instructions) that obey weaker ordering + * rules, but those instructions will only be used in (inline) + * assembly code where we can add the necessary fence instructions + * ourselves. + */ + +#define __membar(_f) do { __asm __volatile(_f ::: "memory"); } while (0) + +#ifdef MULTIPROCESSOR +#define membar_enter() __membar("lock; addl $0,0(%%esp)") +#define membar_exit() __membar("") +#define membar_producer() __membar("") +#define membar_consumer() __membar("") +#define membar_sync() __membar("lock; addl $0,0(%%esp)") +#else +#define membar_enter() __membar("") +#define membar_exit() __membar("") +#define membar_producer() __membar("") +#define membar_consumer() __membar("") +#define membar_sync() __membar("") +#endif + int ucas_32(volatile int32_t *, int32_t, int32_t); #define futex_atomic_ucas_int32 ucas_32 |