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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 17 Jul 2022 13:29:07 -0700
Message-ID: <CAHk-=whjWyoognKy4QUUwf95L6qvPg7MGdp0CxqD2fpvZo7DLw@mail.gmail.com>
Subject: Re: mainline build failure of powerpc allmodconfig for prom_init_check
To:     Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Kees Cook <keescook@chromium.org>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-hardening@vger.kernel.org,
        Segher Boessenkool <segher@kernel.crashing.org>
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On Sun, Jul 17, 2022 at 1:25 PM Sudip Mukherjee
<sudipm.mukherjee@gmail.com> wrote:
>
> And the generated assembly still has the memset for "struct prom_args".

Strange. That smells like a compiler bug to me.

But I can't read powerpc assembly code - it's been too many years, and
even back when I did read it I hated how the register "names" worked.

Maybe it was never the args array, and it was about the other fields.
Not that that makes any sense either, but it makes more sense than the
compiler turning a series of volatile accesses into a memset.

              Linus