diff options
Diffstat (limited to 'sys/powerpc/include')
| -rw-r--r-- | sys/powerpc/include/atomic.h | 34 |
1 files changed, 22 insertions, 12 deletions
diff --git a/sys/powerpc/include/atomic.h b/sys/powerpc/include/atomic.h index 8ec3ea0..20cffba 100644 --- a/sys/powerpc/include/atomic.h +++ b/sys/powerpc/include/atomic.h @@ -36,23 +36,30 @@ #error this file needs sys/cdefs.h as a prerequisite #endif -/* NOTE: lwsync is equivalent to sync on systems without lwsync */ -#define mb() __asm __volatile("lwsync" : : : "memory") -#ifdef __powerpc64__ -#define rmb() __asm __volatile("lwsync" : : : "memory") -#define wmb() __asm __volatile("lwsync" : : : "memory") -#else -#define rmb() __asm __volatile("lwsync" : : : "memory") -#define wmb() __asm __volatile("eieio" : : : "memory") -#endif - /* * The __ATOMIC_REL/ACQ() macros provide memory barriers only in conjunction - * with the atomic lXarx/stXcx. sequences below. See Appendix B.2 of Book II - * of the architecture manual. + * with the atomic lXarx/stXcx. sequences below. They are not exposed outside + * of this file. See also Appendix B.2 of Book II of the architecture manual. + * + * Note that not all Book-E processors accept the light-weight sync variant. + * In particular, early models of E500 cores are known to wedge. Bank on all + * 64-bit capable CPUs to accept lwsync properly and pressimize 32-bit CPUs + * to use the heavier-weight sync. */ + +#ifdef __powerpc64__ +#define mb() __asm __volatile("lwsync" : : : "memory") +#define rmb() __asm __volatile("lwsync" : : : "memory") +#define wmb() __asm __volatile("lwsync" : : : "memory") #define __ATOMIC_REL() __asm __volatile("lwsync" : : : "memory") +#define __ATOMIC_ACQ() __asm __volatile("lwsync" : : : "memory") +#else +#define mb() __asm __volatile("isync" : : : "memory") +#define rmb() __asm __volatile("isync" : : : "memory") +#define wmb() __asm __volatile("isync" : : : "memory") +#define __ATOMIC_REL() __asm __volatile("isync" : : : "memory") #define __ATOMIC_ACQ() __asm __volatile("isync" : : : "memory") +#endif /* * atomic_add(p, v) @@ -683,4 +690,7 @@ atomic_fetchadd_long(volatile u_long *p, u_long v) #define atomic_fetchadd_64 atomic_fetchadd_long #endif +#undef __ATOMIC_REL +#undef __ATOMIC_ACQ + #endif /* ! _MACHINE_ATOMIC_H_ */ |
