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From:   Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date:   Tue, 13 Feb 2018 10:57:25 +0000
Message-ID: <CAKv+Gu93OdaWyMcm3nqV38-RmoYoCceQ4f4DfT65t9amRm_gFA@mail.gmail.com>
Subject: Re: [PATCH] crypto: arm/aes-cipher - move S-box to .rodata section
To:     Jinbum Park <jinb.park7@gmail.com>
Cc:     "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>
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On 12 February 2018 at 13:52, Jinbum Park <jinb.park7@gmail.com> wrote:
> Move the AES inverse S-box to the .rodata section
> where it is safe from abuse by speculation.
>
> Signed-off-by: Jinbum Park <jinb.park7@gmail.com>

Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
>  arch/arm/crypto/aes-cipher-core.S | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm/crypto/aes-cipher-core.S b/arch/arm/crypto/aes-cipher-core.S
> index 54b3840..184d6c2 100644
> --- a/arch/arm/crypto/aes-cipher-core.S
> +++ b/arch/arm/crypto/aes-cipher-core.S
> @@ -174,6 +174,16 @@
>         .ltorg
>         .endm
>
> +ENTRY(__aes_arm_encrypt)
> +       do_crypt        fround, crypto_ft_tab, crypto_ft_tab + 1, 2
> +ENDPROC(__aes_arm_encrypt)
> +
> +       .align          5
> +ENTRY(__aes_arm_decrypt)
> +       do_crypt        iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
> +ENDPROC(__aes_arm_decrypt)
> +
> +       .section        ".rodata", "a"
>         .align          L1_CACHE_SHIFT
>         .type           __aes_arm_inverse_sbox, %object
>  __aes_arm_inverse_sbox:
> @@ -210,12 +220,3 @@ __aes_arm_inverse_sbox:
>         .byte           0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26
>         .byte           0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d
>         .size           __aes_arm_inverse_sbox, . - __aes_arm_inverse_sbox
> -
> -ENTRY(__aes_arm_encrypt)
> -       do_crypt        fround, crypto_ft_tab, crypto_ft_tab + 1, 2
> -ENDPROC(__aes_arm_encrypt)
> -
> -       .align          5
> -ENTRY(__aes_arm_decrypt)
> -       do_crypt        iround, crypto_it_tab, __aes_arm_inverse_sbox, 0
> -ENDPROC(__aes_arm_decrypt)
> --
> 1.9.1
>