From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org, will.deacon@arm.com
Cc: waiman.long@hpe.com, mingo@redhat.com,
paulmck@linux.vnet.ibm.com, boqun.feng@gmail.com,
torvalds@linux-foundation.org, dave@stgolabs.net
Subject: Re: [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait()
Date: Mon, 4 Apr 2016 15:12:05 +0200 [thread overview]
Message-ID: <20160404131205.GT3430@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160404123633.484451002@infradead.org>
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.
> +}
next prev parent reply other threads:[~2016-04-04 13:12 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 12:22 [RFC][PATCH 0/3] smp_cond_load_acquire + cmpwait Peter Zijlstra
2016-04-04 12:22 ` [RFC][PATCH 1/3] locking: Replace smp_cond_acquire with smp_cond_load_acquire Peter Zijlstra
2016-04-04 18:20 ` Waiman Long
2016-04-04 12:22 ` [RFC][PATCH 2/3] locking/qrwlock: Use smp_cond_load_acquire() Peter Zijlstra
2016-04-12 4:58 ` Davidlohr Bueso
2016-04-12 16:45 ` Waiman Long
2016-04-04 12:22 ` [RFC][PATCH 3/3] locking,arm64: Introduce cmpwait() Peter Zijlstra
2016-04-04 13:12 ` Peter Zijlstra [this message]
2016-04-12 16:59 ` Will Deacon
2016-04-13 12:52 ` Peter Zijlstra
2016-04-26 16:33 ` Will Deacon
2016-04-26 17:15 ` Will Deacon
2016-04-26 20:25 ` Peter Zijlstra
2016-04-22 16:08 ` Boqun Feng
2016-04-22 16:53 ` Will Deacon
2016-04-23 4:02 ` Boqun Feng
2016-04-23 2:37 ` Peter Zijlstra
2016-04-23 3:40 ` Boqun Feng
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