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Groups > linux.kernel > #1370610
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() |
| Date | 2016-04-04 15:20 +0200 |
| Message-ID | <rkcAb-3vK-33@gated-at.bofh.it> (permalink) |
| References | <rkbXs-31q-9@gated-at.bofh.it> <rkbXs-31q-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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.
> +}
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[RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() Peter Zijlstra <peterz@infradead.org> - 2016-04-04 14:40 +0200
Re: [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() Peter Zijlstra <peterz@infradead.org> - 2016-04-04 15:20 +0200
Re: [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() Will Deacon <will.deacon@arm.com> - 2016-04-12 19:00 +0200
Re: [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() Peter Zijlstra <peterz@infradead.org> - 2016-04-13 15:00 +0200
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