Le jeudi 26 mai 2011 Ã 14:31 -0700, H. Peter Anvin a Ãcrit :
> On 05/26/2011 02:25 PM, Eric Dumazet wrote:
> >>
> >> +#define cmpxchg16b(ptr, o1, o2, n1, n2) \
> >> +({ \
> >> + char __ret; \
> >> + __typeof__(o2) __junk; \
> >> + __typeof__(*(ptr)) __old1 = (o1); \
> >> + __typeof__(o2) __old2 = (o2); \
> >> + __typeof__(*(ptr)) __new1 = (n1); \
> >> + __typeof__(o2) __new2 = (n2); \
> >> + asm volatile(LOCK_PREFIX_HERE "lock; cmpxchg16b (%%rsi);setz %1" \
> >
> > If there is no emulation, why do you force rsi here ?
> >
> > It could be something else, like "=m" (*ptr) ?
> >
> > (same remark for other functions)
> >
>
> "+m" (*ptr) please...
>
> -hpa
Oh well, I guess I was fooled by :
(arch/x86/include/asm/cmpxchg_32.h)
static inline void set_64bit(volatile u64 *ptr, u64 value)
{
u32 low = value;
u32 high = value >> 32;
u64 prev = *ptr;
asm volatile("\n1:\t"
LOCK_PREFIX "cmpxchg8b %0\n\t"
"jnz 1b"
: "=m" (*ptr), "+A" (prev)
: "b" (low), "c" (high)
: "memory");
}
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