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Date: Sun, 11 Sep 2016 21:58:57 +0800
From: Simon Guo <wei.guo.simon@gmail.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>, Anton Blanchard <anton@samba.org>,
 Cyril Bur <cyrilbur@gmail.com>, Michael Neuling <mikey@neuling.org>,
 Andrew Morton <akpm@linux-foundation.org>,
 Amanieu d'Antras <amanieu@gmail.com>, linuxppc-dev@lists.ozlabs.org,
 linux-kernel@vger.kernel.org,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH] powerpc: set used_vsr/used_vr/used_spe in sigreturn path
 when MSR bits are active
Message-ID: <20160911135857.GA1137@simonLocalRHEL7.x64>
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On Tue, Jul 26, 2016 at 04:06:01PM +0800, wei.guo.simon@gmail.com wrote:
> From: Simon Guo <wei.guo.simon@gmail.com>
> 
> Normally, when MSR[VSX/VR/SPE] bits = 1, the used_vsr/used_vr/used_spe
> bit have already been set. However signal frame locates at user space
> and it is controlled by user application. It is up to kernel to make
> sure used_vsr/used_vr/used_spe(in kernel)=1 and consistent with MSR
> bits.
> 
> For example, CRIU application, who utilizes sigreturn to restore
> checkpointed process, will lead to the case where MSR[VSX] bit is
> active in signal frame, but used_vsx bit is not set. (the same applies
> to VR/SPE).
> 
> This patch will reinforce this at kernel by always setting used_* bit
> when MSR related bits are active in signal frame and we are doing
> sigreturn.
> 
> This patch is based on Ben's Proposal.
> 
Hi Michael,

Just a ping for this patch. 
The history locates at:
http://linuxppc.10917.n7.nabble.com/PATCH-v4-powerpc-Export-thread-struct-used-vr-used-vsr-to-user-space-td110147.html#a110161

If any addtional work required, please let me know.

Thanks,
- Simon