From: Ard Biesheuvel <ardb@xxxxxxxxxx> Now that kernel mode NEON no longer disables preemption, using FP/SIMD in library code which is not obviously part of the crypto subsystem is no longer problematic, as it will no longer incur unexpected latencies. So accelerate the CRC-32 library code on arm64 to use a 4-way interleave, using PMULL instructions to implement the folding. On Apple M2, this results in a speedup of 2 - 2.8x when using input sizes of 1k - 8k. For smaller sizes, the overhead of preserving and restoring the FP/SIMD register file may not be worth it, so 1k is used as a threshold for choosing this code path. The coefficient tables were generated using code provided by Eric. [0] [0] https://github.com/ebiggers/libdeflate/blob/master/scripts/gen_crc32_multipliers.c Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/arm64/lib/crc32-glue.c | 48 ++++ arch/arm64/lib/crc32.S | 231 +++++++++++++++++++- 2 files changed, 276 insertions(+), 3 deletions(-) diff --git a/arch/arm64/lib/crc32-glue.c b/arch/arm64/lib/crc32-glue.c index 0b51761d4b75..295ae3e6b997 100644 --- a/arch/arm64/lib/crc32-glue.c +++ b/arch/arm64/lib/crc32-glue.c @@ -4,16 +4,40 @@ #include <linux/linkage.h> #include <asm/alternative.h> +#include <asm/cpufeature.h> +#include <asm/neon.h> +#include <asm/simd.h> + +#include <crypto/internal/simd.h> + +// The minimum input length to consider the 4-way interleaved code path +static const size_t min_len = 1024; asmlinkage u32 crc32_le_arm64(u32 crc, unsigned char const *p, size_t len); asmlinkage u32 crc32c_le_arm64(u32 crc, unsigned char const *p, size_t len); asmlinkage u32 crc32_be_arm64(u32 crc, unsigned char const *p, size_t len); +asmlinkage u32 crc32_le_arm64_4way(u32 crc, unsigned char const *p, size_t len); +asmlinkage u32 crc32c_le_arm64_4way(u32 crc, unsigned char const *p, size_t len); +asmlinkage u32 crc32_be_arm64_4way(u32 crc, unsigned char const *p, size_t len); + u32 __pure crc32_le(u32 crc, unsigned char const *p, size_t len) { if (!alternative_has_cap_likely(ARM64_HAS_CRC32)) return crc32_le_base(crc, p, len); + if (len >= min_len && cpu_have_named_feature(PMULL) && crypto_simd_usable()) { + kernel_neon_begin(); + crc = crc32_le_arm64_4way(crc, p, len); + kernel_neon_end(); + + p += round_down(len, 64); + len %= 64; + + if (!len) + return crc; + } + return crc32_le_arm64(crc, p, len); } @@ -22,6 +46,18 @@ u32 __pure __crc32c_le(u32 crc, unsigned char const *p, size_t len) if (!alternative_has_cap_likely(ARM64_HAS_CRC32)) return __crc32c_le_base(crc, p, len); + if (len >= min_len && cpu_have_named_feature(PMULL) && crypto_simd_usable()) { + kernel_neon_begin(); + crc = crc32c_le_arm64_4way(crc, p, len); + kernel_neon_end(); + + p += round_down(len, 64); + len %= 64; + + if (!len) + return crc; + } + return crc32c_le_arm64(crc, p, len); } @@ -30,5 +66,17 @@ u32 __pure crc32_be(u32 crc, unsigned char const *p, size_t len) if (!alternative_has_cap_likely(ARM64_HAS_CRC32)) return crc32_be_base(crc, p, len); + if (len >= min_len && cpu_have_named_feature(PMULL) && crypto_simd_usable()) { + kernel_neon_begin(); + crc = crc32_be_arm64_4way(crc, p, len); + kernel_neon_end(); + + p += round_down(len, 64); + len %= 64; + + if (!len) + return crc; + } + return crc32_be_arm64(crc, p, len); } diff --git a/arch/arm64/lib/crc32.S b/arch/arm64/lib/crc32.S index f9920492f135..68825317460f 100644 --- a/arch/arm64/lib/crc32.S +++ b/arch/arm64/lib/crc32.S @@ -1,14 +1,17 @@ /* SPDX-License-Identifier: GPL-2.0-only */ /* - * Accelerated CRC32(C) using AArch64 CRC instructions + * Accelerated CRC32(C) using AArch64 CRC and PMULL instructions * - * Copyright (C) 2016 - 2018 Linaro Ltd <ard.biesheuvel@xxxxxxxxxx> + * Copyright (C) 2016 - 2018 Linaro Ltd. + * Copyright (C) 2024 Google LLC + * + * Author: Ard Biesheuvel <ardb@xxxxxxxxxx> */ #include <linux/linkage.h> #include <asm/assembler.h> - .arch armv8-a+crc + .cpu generic+crc+crypto .macro bitle, reg .endm @@ -135,3 +138,225 @@ SYM_FUNC_END(crc32c_le_arm64) SYM_FUNC_START(crc32_be_arm64) __crc32 order=be SYM_FUNC_END(crc32_be_arm64) + + in .req x1 + len .req x2 + + /* + * w0: input CRC at entry, output CRC at exit + * x1: pointer to input buffer + * x2: length of input in bytes + */ + .macro crc4way, insn, table, order=le + bit\order w0 + lsr len, len, #6 // len := # of 64-byte blocks + + /* Process up to 64 blocks of 64 bytes at a time */ +.La\@: mov x3, #64 + cmp len, #64 + csel x3, x3, len, hi // x3 := min(len, 64) + sub len, len, x3 + + /* Divide the input into 4 contiguous blocks */ + add x4, x3, x3, lsl #1 // x4 := 3 * x3 + add x7, in, x3, lsl #4 // x7 := in + 16 * x3 + add x8, in, x3, lsl #5 // x8 := in + 32 * x3 + add x9, in, x4, lsl #4 // x9 := in + 16 * x4 + + /* Load the folding coefficients from the lookup table */ + adr_l x5, \table - 12 // entry 0 omitted + add x5, x5, x4, lsl #2 // x5 += 12 * x3 + ldp s0, s1, [x5] + ldr s2, [x5, #8] + + /* Zero init partial CRCs for this iteration */ + mov w4, wzr + mov w5, wzr + mov w6, wzr + mov x17, xzr + +.Lb\@: sub x3, x3, #1 + \insn w6, w6, x17 + ldp x10, x11, [in], #16 + ldp x12, x13, [x7], #16 + ldp x14, x15, [x8], #16 + ldp x16, x17, [x9], #16 + + \order x10, x11, x12, x13, x14, x15, x16, x17 + + /* Apply the CRC transform to 4 16-byte blocks in parallel */ + \insn w0, w0, x10 + \insn w4, w4, x12 + \insn w5, w5, x14 + \insn w6, w6, x16 + \insn w0, w0, x11 + \insn w4, w4, x13 + \insn w5, w5, x15 + cbnz x3, .Lb\@ + + /* Combine the 4 partial results into w0 */ + mov v3.d[0], x0 + mov v4.d[0], x4 + mov v5.d[0], x5 + pmull v0.1q, v0.1d, v3.1d + pmull v1.1q, v1.1d, v4.1d + pmull v2.1q, v2.1d, v5.1d + eor v0.8b, v0.8b, v1.8b + eor v0.8b, v0.8b, v2.8b + mov x5, v0.d[0] + eor x5, x5, x17 + \insn w0, w6, x5 + + mov in, x9 + cbnz len, .La\@ + + bit\order w0 + ret + .endm + + .align 5 +SYM_FUNC_START(crc32c_le_arm64_4way) + crc4way crc32cx, .L0 +SYM_FUNC_END(crc32c_le_arm64_4way) + + .align 5 +SYM_FUNC_START(crc32_le_arm64_4way) + crc4way crc32x, .L1 +SYM_FUNC_END(crc32_le_arm64_4way) + + .align 5 +SYM_FUNC_START(crc32_be_arm64_4way) + crc4way crc32x, .L1, be +SYM_FUNC_END(crc32_be_arm64_4way) + + .section .rodata, "a", %progbits + .align 6 +.L0: .long 0xddc0152b, 0xba4fc28e, 0x493c7d27 + .long 0x0715ce53, 0x9e4addf8, 0xba4fc28e + .long 0xc96cfdc0, 0x0715ce53, 0xddc0152b + .long 0xab7aff2a, 0x0d3b6092, 0x9e4addf8 + .long 0x299847d5, 0x878a92a7, 0x39d3b296 + .long 0xb6dd949b, 0xab7aff2a, 0x0715ce53 + .long 0xa60ce07b, 0x83348832, 0x47db8317 + .long 0xd270f1a2, 0xb9e02b86, 0x0d3b6092 + .long 0x65863b64, 0xb6dd949b, 0xc96cfdc0 + .long 0xb3e32c28, 0xbac2fd7b, 0x878a92a7 + .long 0xf285651c, 0xce7f39f4, 0xdaece73e + .long 0x271d9844, 0xd270f1a2, 0xab7aff2a + .long 0x6cb08e5c, 0x2b3cac5d, 0x2162d385 + .long 0xcec3662e, 0x1b03397f, 0x83348832 + .long 0x8227bb8a, 0xb3e32c28, 0x299847d5 + .long 0xd7a4825c, 0xdd7e3b0c, 0xb9e02b86 + .long 0xf6076544, 0x10746f3c, 0x18b33a4e + .long 0x98d8d9cb, 0x271d9844, 0xb6dd949b + .long 0x57a3d037, 0x93a5f730, 0x78d9ccb7 + .long 0x3771e98f, 0x6b749fb2, 0xbac2fd7b + .long 0xe0ac139e, 0xcec3662e, 0xa60ce07b + .long 0x6f345e45, 0xe6fc4e6a, 0xce7f39f4 + .long 0xa2b73df1, 0xb0cd4768, 0x61d82e56 + .long 0x86d8e4d2, 0xd7a4825c, 0xd270f1a2 + .long 0xa90fd27a, 0x0167d312, 0xc619809d + .long 0xca6ef3ac, 0x26f6a60a, 0x2b3cac5d + .long 0x4597456a, 0x98d8d9cb, 0x65863b64 + .long 0xc9c8b782, 0x68bce87a, 0x1b03397f + .long 0x62ec6c6d, 0x6956fc3b, 0xebb883bd + .long 0x2342001e, 0x3771e98f, 0xb3e32c28 + .long 0xe8b6368b, 0x2178513a, 0x064f7f26 + .long 0x9ef68d35, 0x170076fa, 0xdd7e3b0c + .long 0x0b0bf8ca, 0x6f345e45, 0xf285651c + .long 0x02ee03b2, 0xff0dba97, 0x10746f3c + .long 0x135c83fd, 0xf872e54c, 0xc7a68855 + .long 0x00bcf5f6, 0x86d8e4d2, 0x271d9844 + .long 0x58ca5f00, 0x5bb8f1bc, 0x8e766a0c + .long 0xded288f8, 0xb3af077a, 0x93a5f730 + .long 0x37170390, 0xca6ef3ac, 0x6cb08e5c + .long 0xf48642e9, 0xdd66cbbb, 0x6b749fb2 + .long 0xb25b29f2, 0xe9e28eb4, 0x1393e203 + .long 0x45cddf4e, 0xc9c8b782, 0xcec3662e + .long 0xdfd94fb2, 0x93e106a4, 0x96c515bb + .long 0x021ac5ef, 0xd813b325, 0xe6fc4e6a + .long 0x8e1450f7, 0x2342001e, 0x8227bb8a + .long 0xe0cdcf86, 0x6d9a4957, 0xb0cd4768 + .long 0x613eee91, 0xd2c3ed1a, 0x39c7ff35 + .long 0xbedc6ba1, 0x9ef68d35, 0xd7a4825c + .long 0x0cd1526a, 0xf2271e60, 0x0ab3844b + .long 0xd6c3a807, 0x2664fd8b, 0x0167d312 + .long 0x1d31175f, 0x02ee03b2, 0xf6076544 + .long 0x4be7fd90, 0x363bd6b3, 0x26f6a60a + .long 0x6eeed1c9, 0x5fabe670, 0xa741c1bf + .long 0xb3a6da94, 0x00bcf5f6, 0x98d8d9cb + .long 0x2e7d11a7, 0x17f27698, 0x49c3cc9c + .long 0x889774e1, 0xaa7c7ad5, 0x68bce87a + .long 0x8a074012, 0xded288f8, 0x57a3d037 + .long 0xbd0bb25f, 0x6d390dec, 0x6956fc3b + .long 0x3be3c09b, 0x6353c1cc, 0x42d98888 + .long 0x465a4eee, 0xf48642e9, 0x3771e98f + .long 0x2e5f3c8c, 0xdd35bc8d, 0xb42ae3d9 + .long 0xa52f58ec, 0x9a5ede41, 0x2178513a + .long 0x47972100, 0x45cddf4e, 0xe0ac139e + .long 0x359674f7, 0xa51b6135, 0x170076fa + +.L1: .long 0xaf449247, 0x81256527, 0xccaa009e + .long 0x57c54819, 0x1d9513d7, 0x81256527 + .long 0x3f41287a, 0x57c54819, 0xaf449247 + .long 0xf5e48c85, 0x910eeec1, 0x1d9513d7 + .long 0x1f0c2cdd, 0x9026d5b1, 0xae0b5394 + .long 0x71d54a59, 0xf5e48c85, 0x57c54819 + .long 0x1c63267b, 0xfe807bbd, 0x0cbec0ed + .long 0xd31343ea, 0xe95c1271, 0x910eeec1 + .long 0xf9d9c7ee, 0x71d54a59, 0x3f41287a + .long 0x9ee62949, 0xcec97417, 0x9026d5b1 + .long 0xa55d1514, 0xf183c71b, 0xd1df2327 + .long 0x21aa2b26, 0xd31343ea, 0xf5e48c85 + .long 0x9d842b80, 0xeea395c4, 0x3c656ced + .long 0xd8110ff1, 0xcd669a40, 0xfe807bbd + .long 0x3f9e9356, 0x9ee62949, 0x1f0c2cdd + .long 0x1d6708a0, 0x0c30f51d, 0xe95c1271 + .long 0xef82aa68, 0xdb3935ea, 0xb918a347 + .long 0xd14bcc9b, 0x21aa2b26, 0x71d54a59 + .long 0x99cce860, 0x356d209f, 0xff6f2fc2 + .long 0xd8af8e46, 0xc352f6de, 0xcec97417 + .long 0xf1996890, 0xd8110ff1, 0x1c63267b + .long 0x631bc508, 0xe95c7216, 0xf183c71b + .long 0x8511c306, 0x8e031a19, 0x9b9bdbd0 + .long 0xdb3839f3, 0x1d6708a0, 0xd31343ea + .long 0x7a92fffb, 0xf7003835, 0x4470ac44 + .long 0x6ce68f2a, 0x00eba0c8, 0xeea395c4 + .long 0x4caaa263, 0xd14bcc9b, 0xf9d9c7ee + .long 0xb46f7cff, 0x9a1b53c8, 0xcd669a40 + .long 0x60290934, 0x81b6f443, 0x6d40f445 + .long 0x8e976a7d, 0xd8af8e46, 0x9ee62949 + .long 0xdcf5088a, 0x9dbdc100, 0x145575d5 + .long 0x1753ab84, 0xbbf2f6d6, 0x0c30f51d + .long 0x255b139e, 0x631bc508, 0xa55d1514 + .long 0xd784eaa8, 0xce26786c, 0xdb3935ea + .long 0x6d2c864a, 0x8068c345, 0x2586d334 + .long 0x02072e24, 0xdb3839f3, 0x21aa2b26 + .long 0x06689b0a, 0x5efd72f5, 0xe0575528 + .long 0x1e52f5ea, 0x4117915b, 0x356d209f + .long 0x1d3d1db6, 0x6ce68f2a, 0x9d842b80 + .long 0x3796455c, 0xb8e0e4a8, 0xc352f6de + .long 0xdf3a4eb3, 0xc55a2330, 0xb84ffa9c + .long 0x28ae0976, 0xb46f7cff, 0xd8110ff1 + .long 0x9764bc8d, 0xd7e7a22c, 0x712510f0 + .long 0x13a13e18, 0x3e9a43cd, 0xe95c7216 + .long 0xb8ee242e, 0x8e976a7d, 0x3f9e9356 + .long 0x0c540e7b, 0x753c81ff, 0x8e031a19 + .long 0x9924c781, 0xb9220208, 0x3edcde65 + .long 0x3954de39, 0x1753ab84, 0x1d6708a0 + .long 0xf32238b5, 0xbec81497, 0x9e70b943 + .long 0xbbd2cd2c, 0x0925d861, 0xf7003835 + .long 0xcc401304, 0xd784eaa8, 0xef82aa68 + .long 0x4987e684, 0x6044fbb0, 0x00eba0c8 + .long 0x3aa11427, 0x18fe3b4a, 0x87441142 + .long 0x297aad60, 0x02072e24, 0xd14bcc9b + .long 0xf60c5e51, 0x6ef6f487, 0x5b7fdd0a + .long 0x632d78c5, 0x3fc33de4, 0x9a1b53c8 + .long 0x25b8822a, 0x1e52f5ea, 0x99cce860 + .long 0xd4fc84bc, 0x1af62fb8, 0x81b6f443 + .long 0x5690aa32, 0xa91fdefb, 0x688a110e + .long 0x1357a093, 0x3796455c, 0xd8af8e46 + .long 0x798fdd33, 0xaaa18a37, 0x357b9517 + .long 0xc2815395, 0x54d42691, 0x9dbdc100 + .long 0x21cfc0f7, 0x28ae0976, 0xf1996890 + .long 0xa0decef3, 0x7b4aa8b7, 0xbbf2f6d6 -- 2.47.0.rc1.288.g06298d1525-goog
