Re: [PATCH 00/12] x86/crypto: Fix RBP usage in several crypto .S files

[Ingo Molnar]

* Eric Biggers <ebiggers3@xxxxxxxxx> wrote:

> On Fri, Sep 15, 2017 at 07:34:31AM +0200, Ingo Molnar wrote:
> > 
> > * Eric Biggers <ebiggers3@xxxxxxxxx> wrote:
> > 
> > > Hi Josh,
> > > 
> > > On Wed, Sep 13, 2017 at 05:33:03PM -0500, Josh Poimboeuf wrote:
> > > > And here's v2 of the sha512-avx2 patch.  It should hopefully gain back
> > > > most of the performance lost by v1.
> > > > 
> > > > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > > > Subject: [PATCH] x86/crypto: Fix RBP usage in sha512-avx2-asm.S
> > > > 
> > > > Using RBP as a temporary register breaks frame pointer convention and
> > > > breaks stack traces when unwinding from an interrupt in the crypto code.
> > > > 
> > > > Mix things up a little bit to get rid of the RBP usage, without
> > > > destroying performance.  Use RDI instead of RBP for the TBL pointer.
> > > > That will clobber CTX, so save CTX on the stack and use RDI as CTX
> > > > before it gets clobbered, and R12 as CTX after it gets clobbered.
> > > > 
> > > > Also remove the unused y4 variable.
> > > > 
> > > 
> > > I tested the v2 patches for both sha256-avx2 and sha512-avx2 on Skylake.  They
> > > both pass the crypto self-tests, and there was no noticable performance
> > > difference compared to the unpatched versions.  Thanks!
> > 
> > Cool, thanks for review and the testing! Can we add your Tested-by + Acked-by tags 
> > to the patches?
> > 
> 
> Yes, that's fine for all the patches in the series.
> 
> Will these patches go in through the crypto tree or through the x86 tree?

Indeed, I suspect they should go through the crypto tree, these fixes are 
independent, they don't depend on anything in the x86 tree.

Thanks,

	Ingo