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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 23 Jan 2023 11:19:15 +0100
Message-ID: <CAMj1kXEk0Vpf6-_iVwyg36MWtQa5HXGdExDzaFU5-12179shmw@mail.gmail.com>
Subject: Re: [PATCH v2 4/6] riscv: Fix EFI stub usage of KASAN instrumented
 strcmp function
To:     Alexandre Ghiti <alexghiti@rivosinc.com>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        kasan-dev@googlegroups.com, linux-efi@vger.kernel.org,
        Alexandre Ghiti <alexghiti@alexghiti.eu.rivosinc.com>
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On Mon, 23 Jan 2023 at 11:14, Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> From: Alexandre Ghiti <alexghiti@alexghiti.eu.rivosinc.com>
>
> The EFI stub must not use any KASAN instrumented code as the kernel
> proper did not initialize the thread pointer and the mapping for the
> KASAN shadow region.
>
> Avoid using the generic strcmp function, instead use the one in
> drivers/firmware/efi/libstub/string.c.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
>  arch/riscv/kernel/image-vars.h | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h
> index 7e2962ef73f9..15616155008c 100644
> --- a/arch/riscv/kernel/image-vars.h
> +++ b/arch/riscv/kernel/image-vars.h
> @@ -23,8 +23,6 @@
>   * linked at. The routines below are all implemented in assembler in a
>   * position independent manner
>   */
> -__efistub_strcmp               = strcmp;
> -
>  __efistub__start               = _start;
>  __efistub__start_kernel                = _start_kernel;
>  __efistub__end                 = _end;
> --
> 2.37.2
>