From: Will Deacon <will.deacon@arm.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: "julien.grall@citrix.com" <julien.grall@citrix.com>,
Catalin Marinas <Catalin.Marinas@arm.com>,
"stefano.stabellini@eu.citrix.com"
<stefano.stabellini@eu.citrix.com>, Tim Deegan <tim@xen.org>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [PATCH 2/3] xen/arm64: resync atomics and spinlock asm with Linux
Date: Mon, 29 Jul 2013 19:05:49 +0100 [thread overview]
Message-ID: <20130729180549.GO32383@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <1375114382.11701.21.camel@kazak.uk.xensource.com>
On Mon, Jul 29, 2013 at 05:13:02PM +0100, Ian Campbell wrote:
> On Mon, 2013-07-29 at 17:02 +0100, Tim Deegan wrote:
> > But I don't understand the new 'memory' clobbers around in this patch.
> > Or rather, I don't understand why there are memory clobbers but not
> > DMBs.
The acquire/release instructions imply half barriers, but GCC may still
re-order instructions across them unless we include the memory clobber.
Will
next prev parent reply other threads:[~2013-07-29 18:05 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-19 15:19 [PATCH 0/3] xen: arm: update asm primitives (bitops, spinlocks, atomics) Ian Campbell
2013-07-19 15:20 ` [PATCH 1/3] xen/arm64: Assembly optimized bitops from Linux Ian Campbell
2013-07-19 15:20 ` [PATCH 2/3] xen/arm64: resync atomics and spinlock asm with Linux Ian Campbell
2013-07-29 16:02 ` Tim Deegan
2013-07-29 16:13 ` Ian Campbell
2013-07-29 18:05 ` Will Deacon [this message]
2013-07-30 9:34 ` Ian Campbell
2013-07-30 9:45 ` Will Deacon
2013-07-30 9:55 ` Ian Campbell
2013-07-30 9:59 ` Will Deacon
2013-07-30 10:12 ` Ian Campbell
2013-07-19 15:20 ` [PATCH 3/3] xen: arm: retry trylock if strex fails on free lock Ian Campbell
2013-07-29 15:52 ` Tim Deegan
2013-07-29 16:20 ` Ian Campbell
2013-07-29 16:25 ` Tim Deegan
2013-08-22 14:56 ` [PATCH 0/3] xen: arm: update asm primitives (bitops, spinlocks, atomics) Ian Campbell
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