diff options
| author | John Baldwin <jhb@FreeBSD.org> | 2001-01-14 09:55:21 +0000 |
|---|---|---|
| committer | John Baldwin <jhb@FreeBSD.org> | 2001-01-14 09:55:21 +0000 |
| commit | 9d979d8912a96e48e561cd23758ef9d2120cff8c (patch) | |
| tree | e893049305059ec784a3351b7dbe3be0a3d250f4 /sys/amd64 | |
| parent | e61b54647ed99d53fef92ee98d3b2df1b055ce38 (diff) | |
Notes
Diffstat (limited to 'sys/amd64')
| -rw-r--r-- | sys/amd64/include/atomic.h | 48 |
1 files changed, 43 insertions, 5 deletions
diff --git a/sys/amd64/include/atomic.h b/sys/amd64/include/atomic.h index 252cb0d8c049..54ed51d9b6e9 100644 --- a/sys/amd64/include/atomic.h +++ b/sys/amd64/include/atomic.h @@ -255,10 +255,19 @@ ATOMIC_ACQ_REL(subtract, long) #undef ATOMIC_ACQ_REL +#if defined(KLD_MODULE) +#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ +u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \ +void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v); +#else +#if defined(I386_CPU) /* * We assume that a = b will do atomic loads and stores. + * + * XXX: This is _NOT_ safe on a P6 or higher because it does not guarantee + * memory ordering. These should only be used on a 386. */ -#define ATOMIC_STORE_LOAD(TYPE) \ +#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ static __inline u_##TYPE \ atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ { \ @@ -271,11 +280,40 @@ atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ *p = v; \ __asm __volatile("" : : : "memory"); \ } +#else + +#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \ +static __inline u_##TYPE \ +atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ +{ \ + u_##TYPE res; \ + \ + __asm __volatile(MPLOCKED LOP \ + : "+a" (res), /* 0 (result) */\ + "+m" (*p) /* 1 */ \ + : : "memory"); \ + \ + return (res); \ +} \ + \ +/* \ + * The XCHG instruction asserts LOCK automagically. \ + */ \ +static __inline void \ +atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ +{ \ + __asm __volatile(SOP \ + : "+m" (*p), /* 0 */ \ + "+r" (v) /* 1 */ \ + : : "memory"); \ +} +#endif /* defined(I386_CPU) */ +#endif /* defined(KLD_MODULE) */ -ATOMIC_STORE_LOAD(char) -ATOMIC_STORE_LOAD(short) -ATOMIC_STORE_LOAD(int) -ATOMIC_STORE_LOAD(long) +ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0") +ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0") +ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0") +ATOMIC_STORE_LOAD(long, "cmpxchgl %0,%1", "xchgl %1,%0") #undef ATOMIC_STORE_LOAD |