00f463b38a
Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
112 lines
2.2 KiB
C
112 lines
2.2 KiB
C
/*
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* Carry-less multiply operations.
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* SPDX-License-Identifier: GPL-2.0-or-later
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*
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* Copyright (C) 2023 Linaro, Ltd.
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*/
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#include "qemu/osdep.h"
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#include "crypto/clmul.h"
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uint64_t clmul_8x8_low(uint64_t n, uint64_t m)
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{
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uint64_t r = 0;
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for (int i = 0; i < 8; ++i) {
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uint64_t mask = (n & 0x0101010101010101ull) * 0xff;
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r ^= m & mask;
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m = (m << 1) & 0xfefefefefefefefeull;
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n >>= 1;
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}
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return r;
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}
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static uint64_t clmul_8x4_even_int(uint64_t n, uint64_t m)
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{
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uint64_t r = 0;
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for (int i = 0; i < 8; ++i) {
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uint64_t mask = (n & 0x0001000100010001ull) * 0xffff;
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r ^= m & mask;
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n >>= 1;
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m <<= 1;
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}
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return r;
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}
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uint64_t clmul_8x4_even(uint64_t n, uint64_t m)
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{
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n &= 0x00ff00ff00ff00ffull;
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m &= 0x00ff00ff00ff00ffull;
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return clmul_8x4_even_int(n, m);
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}
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uint64_t clmul_8x4_odd(uint64_t n, uint64_t m)
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{
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return clmul_8x4_even(n >> 8, m >> 8);
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}
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static uint64_t unpack_8_to_16(uint64_t x)
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{
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return (x & 0x000000ff)
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| ((x & 0x0000ff00) << 8)
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| ((x & 0x00ff0000) << 16)
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| ((x & 0xff000000) << 24);
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}
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uint64_t clmul_8x4_packed(uint32_t n, uint32_t m)
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{
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return clmul_8x4_even_int(unpack_8_to_16(n), unpack_8_to_16(m));
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}
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uint64_t clmul_16x2_even(uint64_t n, uint64_t m)
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{
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uint64_t r = 0;
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n &= 0x0000ffff0000ffffull;
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m &= 0x0000ffff0000ffffull;
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for (int i = 0; i < 16; ++i) {
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uint64_t mask = (n & 0x0000000100000001ull) * 0xffffffffull;
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r ^= m & mask;
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n >>= 1;
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m <<= 1;
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}
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return r;
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}
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uint64_t clmul_16x2_odd(uint64_t n, uint64_t m)
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{
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return clmul_16x2_even(n >> 16, m >> 16);
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}
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uint64_t clmul_32(uint32_t n, uint32_t m32)
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{
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uint64_t r = 0;
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uint64_t m = m32;
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for (int i = 0; i < 32; ++i) {
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r ^= n & 1 ? m : 0;
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n >>= 1;
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m <<= 1;
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}
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return r;
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}
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Int128 clmul_64_gen(uint64_t n, uint64_t m)
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{
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uint64_t rl = 0, rh = 0;
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/* Bit 0 can only influence the low 64-bit result. */
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if (n & 1) {
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rl = m;
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}
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for (int i = 1; i < 64; ++i) {
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uint64_t mask = -((n >> i) & 1);
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rl ^= (m << i) & mask;
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rh ^= (m >> (64 - i)) & mask;
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}
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return int128_make128(rl, rh);
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}
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