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

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Message-ID: <20170915053710.l54tgafyku2bfkbx@gmail.com>
Date:   Fri, 15 Sep 2017 07:37:10 +0200
From:   Ingo Molnar <mingo@...nel.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     Eric Biggers <ebiggers3@...il.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Mathias Krause <minipli@...glemail.com>,
        Chandramouli Narayanan <mouli@...ux.intel.com>,
        Jussi Kivilinna <jussi.kivilinna@....fi>,
        Peter Zijlstra <peterz@...radead.org>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        linux-crypto@...r.kernel.org, Eric Biggers <ebiggers@...gle.com>,
        Andy Lutomirski <luto@...nel.org>, Jiri Slaby <jslaby@...e.cz>
Subject: Re: [PATCH 00/12] x86/crypto: Fix RBP usage in several crypto .S
 files


* Josh Poimboeuf <jpoimboe@...hat.com> wrote:

> > So if this observation of mine is true we could go back to the old code for the 
> > hotpath, but use RDI for TBL and not reload it in the hotpath.
> 
> Thanks for the excellent breakdown.
> 
> When I looked at the patch again, I came to the same conclusion as your
> #4, which is that RDI isn't being used in the inner loops.  It *is* used
> in the outermost loop, however.
> 
> So v2 of my sha512-avx2-asm.S patch spilled CTX onto the stack, instead
> of TBL:
> 
>   https://lkml.kernel.org/r/20170913223303.pskmy2v7nto6rvtg@treble

Indeed - I should have checked your v2 patch, but somehow missed it. Would have 
saved me some looking+typing ;-)

Thanks,

	Ingo