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target/riscv: Use existing lookup tables for MixColumns

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The AES MixColumns and InvMixColumns operations are relatively
expensive 4x4 matrix multiplications in GF(2^8), which is why C
implementations usually rely on precomputed lookup tables rather than
performing the calculations on demand.

Given that we already carry those tables in QEMU, we can just grab the
right value in the implementation of the RISC-V AES32 instructions. Note
that the tables in question are permuted according to the respective
Sbox, so we can omit the Sbox lookup as well in this case.

Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Zewen Ye <lustrew@foxmail.com>
Cc: Weiwei Li <liweiwei@iscas.ac.cn>
Cc: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20230731084043.1791984-1-ardb@kernel.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Ard Biesheuvel 2023-07-31 10:40:43 +02:00 • committed by Alistair Francis
parent 4cc9f284d5
commit 9ea17007c4
3 changed files with 13 additions and 32 deletions
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4
crypto/aes.c
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@ -272,7 +272,7 @@ AES_Td3[x] = Si[x].[09, 0d, 0b, 0e];
AES_Td4[x] = Si[x].[01, 01, 01, 01];
*/
static const uint32_t AES_Te0[256] = {
const uint32_t AES_Te0[256] = {
0xc66363a5U, 0xf87c7c84U, 0xee777799U, 0xf67b7b8dU,
0xfff2f20dU, 0xd66b6bbdU, 0xde6f6fb1U, 0x91c5c554U,
0x60303050U, 0x02010103U, 0xce6767a9U, 0x562b2b7dU,
@ -607,7 +607,7 @@ static const uint32_t AES_Te4[256] = {
0xb0b0b0b0U, 0x54545454U, 0xbbbbbbbbU, 0x16161616U,
};
static const uint32_t AES_Td0[256] = {
const uint32_t AES_Td0[256] = {
0x51f4a750U, 0x7e416553U, 0x1a17a4c3U, 0x3a275e96U,
0x3bab6bcbU, 0x1f9d45f1U, 0xacfa58abU, 0x4be30393U,
0x2030fa55U, 0xad766df6U, 0x88cc7691U, 0xf5024c25U,