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Date:   Tue, 27 Sep 2022 14:14:22 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        llvm@lists.linux.dev, Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v3] x86, mem: move memmove to out of line assembler
Message-ID: <202209271413.314FCFC3@keescook>
References: <202209271333.10AE3E1D@keescook>
 <20220927210248.3950201-1-ndesaulniers@google.com>
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On Tue, Sep 27, 2022 at 02:02:48PM -0700, Nick Desaulniers wrote:
> [...]
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> Changes v2 -> v3:
> * Fix bug I introduced in v1 when I changed one of temp register
>   operands for one of the two instructions performing a mem to mem swap,
>   but not the other instruction's operand, and discovered by Kees.
>   Verified KUnit memcpy tests are passing via:
>   $ ./tools/testing/kunit/kunit.py run --arch=i386 --make_options LLVM=1
>   $ ./tools/testing/kunit/kunit.py run --arch=i386
>   Fixed by using symbolic identifiers rather than open coded registers
>   for the less-than-word-size temporary registers.
> * Expand the comment about callee saved registers on i386 with a
>   reference to the psABI.

Thanks! This looks good.

Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook