PERFORCE change 72454 for review

[Jake Burkholder]

John Baldwin wrote:

>http://perforce.freebsd.org/chv.cgi?CH=72454
>
>Change 72454 by jhb at jhb_slimer on 2005/03/03 22:11:16
>
>	Clobber all memory for atomic ops with an acquire barrier.
>	
>	Suggested by:	   alc
>
>Affected files ...
>
>.. //depot/projects/smpng/sys/sparc64/include/atomic.h#7 edit
>
>Differences ...
>
>==== //depot/projects/smpng/sys/sparc64/include/atomic.h#7 (text+ko) ====
>
>@@ -90,6 +90,7 @@
> 	itype(sz) v;							\
> 	v = atomic_cas(p, e, s, sz);					\
> 	membar(LoadLoad | LoadStore);					\
>+	__asm __volatile("" : : : "memory");				\
> 	v;								\
> })
> 
>@@ -115,6 +116,7 @@
> 	itype(sz) t;							\
> 	t = atomic_op(p, op, v, sz);					\
> 	membar(LoadLoad | LoadStore);					\
>+	__asm __volatile("" : : : "memory");				\
> 	t;								\
> })
> 
>@@ -132,6 +134,7 @@
> 	itype(sz) v;							\
> 	v = atomic_load(p, sz);						\
> 	membar(LoadLoad | LoadStore);					\
>+	__asm __volatile("" : : : "memory");				\
> 	v;								\
> })
> 
>
>  
>
membar already has a memory clobber fwiw.

Jake