Re: [PATCH] powerpc: set used_vsr/used_vr/used_spe in sigreturn path when MSR bits are active

On Tue, Jul 26, 2016 at 04:06:01PM +0800, wei.guo.simon@gmail.com wrote:

From: Simon Guo <redacted>

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