On Mon, Apr 04, 2016 at 02:22:53PM +0200, Peter Zijlstra wrote:
> +#define __CMPWAIT_GEN(w, sz, name) \
+static inline \
> +void __cmpwait_case_##name(volatile void *ptr, unsigned long val) \
> +{ \
> + unsigned long tmp; \
> + \
> + asm volatile( \
> + " ldxr" #sz "\t%" #w "[tmp], %[v]\n" \
> + " eor %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n" \
> + " cbnz %" #w "[tmp], 1f\n" \
> + " wfe\n" \
> + "1:" \
> + : [tmp] "=&r" (tmp), [val] "=&r" (val), \
> + [v] "+Q" (*(unsigned long *)ptr)); \
And this probably wants a "memory" clobber to force reload values after
this returns.
> +}
