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From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Fri, 21 Jan 2022 12:51:40 -0800
Message-ID: <CABCJKuf=eHuFfNjD-7FBTeft3XNTkEc4G9cDvYpMJgH_se12eg@mail.gmail.com>
Subject: Re: [PATCH] lib/crypto: blake2s: avoid indirect calls to compression
 function for Clang CFI
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     Eric Biggers <ebiggers@kernel.org>,
        Miles Chen <miles.chen@mediatek.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "moderated list:ARM/Mediatek SoC..." 
        <linux-mediatek@lists.infradead.org>,
        Nick Desaulniers <ndesaulniers@google.com>
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Hi Jason,

On Fri, Jan 21, 2022 at 12:23 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> On Fri, Jan 21, 2022 at 8:54 PM Eric Biggers <ebiggers@kernel.org> wrote:
> > There are some lines over 80 columns in this patch.
>
> I'll fix that up.
>
> > Otherwise this looks fine.  It would be really nice to fix this in clang,
> > though.
>
> I agree. I'm wondering whether it makes sense to roll with this patch,
> or to just not change anything and lean on Clang upstream to fix their
> bug. Full LTO is marked as "experimental" still. On the other hand,
> Android ships with it turned on, so how "experimental" can it really
> be? I don't have a strong read on the Clang ecosystem to know what
> makes most sense, to apply this or not. Do you have an opinion?

We'll work on fixing the compiler, but please note that it's most
likely going to take a while, so I would prefer to work around the
issue in the kernel for now.

Sami