Implement a NEON fallback for systems that do support NEON but have no support for the optional 64x64->128 polynomial multiplication instruction that is part of the ARMv8 Crypto Extensions. It is based on the paper "Fast Software Polynomial Multiplication on ARM Processors Using the NEON Engine" by Danilo Camara, Conrado Gouvea, Julio Lopez and Ricardo Dahab (https://hal.inria.fr/hal-01506572), but has been reworked extensively for the AArch64 ISA. On a low-end core such as the Cortex-A53 found in the Raspberry Pi3, the NEON based implementation is 4x faster than the table based one, and is time invariant as well, making it less vulnerable to timing attacks. When combined with the bit-sliced NEON implementation of AES-CTR, the AES-GCM performance increases by ~2x (from 58 to 30 cycles per byte). Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> --- v2: - use alternative reduction and precomputed coefficients for loop invariants - refactor asm macros for better legibility arch/arm64/crypto/ghash-ce-core.S | 251 +++++++++++++++++--- arch/arm64/crypto/ghash-ce-glue.c | 40 +++- 2 files changed, 255 insertions(+), 36 deletions(-) diff --git a/arch/arm64/crypto/ghash-ce-core.S b/arch/arm64/crypto/ghash-ce-core.S index cb22459eba85..5d40b99ca3ac 100644 --- a/arch/arm64/crypto/ghash-ce-core.S +++ b/arch/arm64/crypto/ghash-ce-core.S @@ -1,7 +1,7 @@ /* * Accelerated GHASH implementation with ARMv8 PMULL instructions. * - * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@xxxxxxxxxx> + * Copyright (C) 2014 - 2017 Linaro Ltd. <ard.biesheuvel@xxxxxxxxxx> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published @@ -11,31 +11,219 @@ #include <linux/linkage.h> #include <asm/assembler.h> - SHASH .req v0 - SHASH2 .req v1 - T1 .req v2 - T2 .req v3 - MASK .req v4 - XL .req v5 - XM .req v6 - XH .req v7 - IN1 .req v7 + SHASH .req v0 + SHASH2 .req v1 + T1 .req v2 + T2 .req v3 + MASK .req v4 + XL .req v5 + XM .req v6 + XH .req v7 + IN1 .req v7 + + k00_16 .req v8 + k32_48 .req v9 + + t3 .req v10 + t4 .req v11 + t5 .req v12 + t6 .req v13 + t7 .req v14 + t8 .req v15 + t9 .req v16 + + perm1 .req v17 + perm2 .req v18 + perm3 .req v19 + + sh1 .req v20 + sh2 .req v21 + sh3 .req v22 + sh4 .req v23 + + ss1 .req v24 + ss2 .req v25 + ss3 .req v26 + ss4 .req v27 + + VZR .req v28 .text .arch armv8-a+crypto - /* - * void pmull_ghash_update(int blocks, u64 dg[], const char *src, - * struct ghash_key const *k, const char *head) - */ -ENTRY(pmull_ghash_update) + .macro __pmull_p64, rd, rn, rm + pmull \rd\().1q, \rn\().1d, \rm\().1d + .endm + + .macro __pmull2_p64, rd, rn, rm + pmull2 \rd\().1q, \rn\().2d, \rm\().2d + .endm + + .macro __pmull_p8, rq, ad, bd + ext t3.8b, \ad\().8b, \ad\().8b, #1 // A1 + ext t5.8b, \ad\().8b, \ad\().8b, #2 // A2 + ext t7.8b, \ad\().8b, \ad\().8b, #3 // A3 + + __pmull_p8_\bd \rq, \ad + .endm + + .macro __pmull2_p8, rq, ad, bd + tbl t3.16b, {\ad\().16b}, perm1.16b // A1 + tbl t5.16b, {\ad\().16b}, perm2.16b // A2 + tbl t7.16b, {\ad\().16b}, perm3.16b // A3 + + __pmull2_p8_\bd \rq, \ad + .endm + + .macro __pmull_p8_SHASH, rq, ad + __pmull_p8_tail \rq, \ad\().8b, SHASH.8b, 8b,, sh1, sh2, sh3, sh4 + .endm + + .macro __pmull_p8_SHASH2, rq, ad + __pmull_p8_tail \rq, \ad\().8b, SHASH2.8b, 8b,, ss1, ss2, ss3, ss4 + .endm + + .macro __pmull2_p8_SHASH, rq, ad + __pmull_p8_tail \rq, \ad\().16b, SHASH.16b, 16b, 2, sh1, sh2, sh3, sh4 + .endm + + .macro __pmull_p8_tail, rq, ad, bd, nb, t, b1, b2, b3, b4 + pmull\t t3.8h, t3.\nb, \bd // F = A1*B + pmull\t t4.8h, \ad, \b1\().\nb // E = A*B1 + pmull\t t5.8h, t5.\nb, \bd // H = A2*B + pmull\t t6.8h, \ad, \b2\().\nb // G = A*B2 + pmull\t t7.8h, t7.\nb, \bd // J = A3*B + pmull\t t8.8h, \ad, \b3\().\nb // I = A*B3 + pmull\t t9.8h, \ad, \b4\().\nb // K = A*B4 + pmull\t \rq\().8h, \ad, \bd // D = A*B + + eor t3.16b, t3.16b, t4.16b // L = E + F + eor t5.16b, t5.16b, t6.16b // M = G + H + eor t7.16b, t7.16b, t8.16b // N = I + J + + uzp1 t4.2d, t3.2d, t5.2d + uzp2 t3.2d, t3.2d, t5.2d + uzp1 t6.2d, t7.2d, t9.2d + uzp2 t7.2d, t7.2d, t9.2d + + // t3 = (L) (P0 + P1) << 8 + // t5 = (M) (P2 + P3) << 16 + eor t4.16b, t4.16b, t3.16b + and t3.16b, t3.16b, k32_48.16b + + // t7 = (N) (P4 + P5) << 24 + // t9 = (K) (P6 + P7) << 32 + eor t6.16b, t6.16b, t7.16b + and t7.16b, t7.16b, k00_16.16b + + eor t4.16b, t4.16b, t3.16b + eor t6.16b, t6.16b, t7.16b + + zip2 t5.2d, t4.2d, t3.2d + zip1 t3.2d, t4.2d, t3.2d + zip2 t9.2d, t6.2d, t7.2d + zip1 t7.2d, t6.2d, t7.2d + + ext t3.16b, t3.16b, t3.16b, #15 + ext t5.16b, t5.16b, t5.16b, #14 + ext t7.16b, t7.16b, t7.16b, #13 + ext t9.16b, t9.16b, t9.16b, #12 + + eor t3.16b, t3.16b, t5.16b + eor t7.16b, t7.16b, t9.16b + eor \rq\().16b, \rq\().16b, t3.16b + eor \rq\().16b, \rq\().16b, t7.16b + .endm + + .macro __pmull_pre_p64 + movi MASK.16b, #0xe1 + shl MASK.2d, MASK.2d, #57 + .endm + + .macro __pmull_pre_p8 + // k00_16 := 0x0000000000000000_000000000000ffff + // k32_48 := 0x00000000ffffffff_0000ffffffffffff + movi k32_48.2d, #0xffffffff + mov k32_48.h[2], k32_48.h[0] + ushr k00_16.2d, k32_48.2d, #32 + + // prepare the permutation vectors + mov_q x5, 0x080f0e0d0c0b0a09 + movi T1.8b, #8 + dup perm1.2d, x5 + eor perm1.16b, perm1.16b, T1.16b + ushr perm2.2d, perm1.2d, #8 + ushr perm3.2d, perm1.2d, #16 + ushr T1.2d, perm1.2d, #24 + sli perm2.2d, perm1.2d, #56 + sli perm3.2d, perm1.2d, #48 + sli T1.2d, perm1.2d, #40 + + // precompute loop invariants + tbl sh1.16b, {SHASH.16b}, perm1.16b + tbl sh2.16b, {SHASH.16b}, perm2.16b + tbl sh3.16b, {SHASH.16b}, perm3.16b + tbl sh4.16b, {SHASH.16b}, T1.16b + ext ss1.8b, SHASH2.8b, SHASH2.8b, #1 + ext ss2.8b, SHASH2.8b, SHASH2.8b, #2 + ext ss3.8b, SHASH2.8b, SHASH2.8b, #3 + ext ss4.8b, SHASH2.8b, SHASH2.8b, #4 + + movi VZR.16b, #0 + .endm + + // + // PMULL (64x64->128) based reduction for CPUs that can do + // it in a single instruction. + // + .macro __pmull_reduce_p64 + ext T1.16b, XL.16b, XH.16b, #8 + pmull T2.1q, XL.1d, MASK.1d + eor XM.16b, XM.16b, T1.16b + + mov XH.d[0], XM.d[1] + mov XM.d[1], XL.d[0] + + eor XL.16b, XM.16b, T2.16b + ext T2.16b, XL.16b, XL.16b, #8 + pmull XL.1q, XL.1d, MASK.1d + .endm + + // + // Alternative reduction for CPUs that lack support for the + // 64x64->128 PMULL instruction + // + .macro __pmull_reduce_p8 + ext T2.16b, VZR.16b, XM.16b, #8 + ext XM.16b, XM.16b, VZR.16b, #8 + eor XL.16b, XL.16b, T2.16b + eor XH.16b, XH.16b, XM.16b + + shl T2.2d, XL.2d, #1 + eor T2.16b, T2.16b, XL.16b + shl T2.2d, T2.2d, #5 + eor T2.16b, T2.16b, XL.16b + shl T2.2d, T2.2d, #57 + ext XM.16b, VZR.16b, T2.16b, #8 + ext T2.16b, T2.16b, VZR.16b, #8 + eor XL.16b, XL.16b, XM.16b + eor XH.16b, XH.16b, T2.16b + + ushr T2.2d, XL.2d, #5 + eor T2.16b, T2.16b, XL.16b + ushr T2.2d, T2.2d, #1 + eor T2.16b, T2.16b, XL.16b + ushr T2.2d, T2.2d, #1 + .endm + + .macro __pmull_ghash, pn ld1 {SHASH.2d}, [x3] ld1 {XL.2d}, [x1] - movi MASK.16b, #0xe1 ext SHASH2.16b, SHASH.16b, SHASH.16b, #8 - shl MASK.2d, MASK.2d, #57 eor SHASH2.16b, SHASH2.16b, SHASH.16b + __pmull_pre_\pn + /* do the head block first, if supplied */ cbz x4, 0f ld1 {T1.2d}, [x4] @@ -52,23 +240,16 @@ CPU_LE( rev64 T1.16b, T1.16b ) eor T1.16b, T1.16b, T2.16b eor XL.16b, XL.16b, IN1.16b - pmull2 XH.1q, SHASH.2d, XL.2d // a1 * b1 + __pmull2_\pn XH, XL, SHASH // a1 * b1 eor T1.16b, T1.16b, XL.16b - pmull XL.1q, SHASH.1d, XL.1d // a0 * b0 - pmull XM.1q, SHASH2.1d, T1.1d // (a1 + a0)(b1 + b0) + __pmull_\pn XL, XL, SHASH // a0 * b0 + __pmull_\pn XM, T1, SHASH2 // (a1 + a0)(b1 + b0) - ext T1.16b, XL.16b, XH.16b, #8 eor T2.16b, XL.16b, XH.16b - eor XM.16b, XM.16b, T1.16b eor XM.16b, XM.16b, T2.16b - pmull T2.1q, XL.1d, MASK.1d - mov XH.d[0], XM.d[1] - mov XM.d[1], XL.d[0] + __pmull_reduce_\pn - eor XL.16b, XM.16b, T2.16b - ext T2.16b, XL.16b, XL.16b, #8 - pmull XL.1q, XL.1d, MASK.1d eor T2.16b, T2.16b, XH.16b eor XL.16b, XL.16b, T2.16b @@ -76,7 +257,19 @@ CPU_LE( rev64 T1.16b, T1.16b ) st1 {XL.2d}, [x1] ret -ENDPROC(pmull_ghash_update) + .endm + + /* + * void pmull_ghash_update(int blocks, u64 dg[], const char *src, + * struct ghash_key const *k, const char *head) + */ +ENTRY(pmull_ghash_update_p64) + __pmull_ghash p64 +ENDPROC(pmull_ghash_update_p64) + +ENTRY(pmull_ghash_update_p8) + __pmull_ghash p8 +ENDPROC(pmull_ghash_update_p8) KS .req v8 CTR .req v9 diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c index 524dd5a5aca1..45d49d293d0d 100644 --- a/arch/arm64/crypto/ghash-ce-glue.c +++ b/arch/arm64/crypto/ghash-ce-glue.c @@ -26,6 +26,7 @@ MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions"); MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>"); MODULE_LICENSE("GPL v2"); +MODULE_ALIAS_CRYPTO("ghash"); #define GHASH_BLOCK_SIZE 16 #define GHASH_DIGEST_SIZE 16 @@ -48,8 +49,17 @@ struct gcm_aes_ctx { struct ghash_key ghash_key; }; -asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src, - struct ghash_key const *k, const char *head); +asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src, + struct ghash_key const *k, + const char *head); + +asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src, + struct ghash_key const *k, + const char *head); + +static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src, + struct ghash_key const *k, + const char *head); asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[], const u8 src[], struct ghash_key const *k, @@ -554,13 +564,24 @@ static int __init ghash_ce_mod_init(void) { int ret; - ret = crypto_register_aead(&gcm_aes_alg); - if (ret) - return ret; + if (!(elf_hwcap & HWCAP_ASIMD)) + return -ENODEV; + + if (elf_hwcap & HWCAP_PMULL) + pmull_ghash_update = pmull_ghash_update_p64; + + else + pmull_ghash_update = pmull_ghash_update_p8; ret = crypto_register_shash(&ghash_alg); if (ret) - crypto_unregister_aead(&gcm_aes_alg); + return ret; + + if (elf_hwcap & HWCAP_PMULL) { + ret = crypto_register_aead(&gcm_aes_alg); + if (ret) + crypto_unregister_shash(&ghash_alg); + } return ret; } @@ -570,5 +591,10 @@ static void __exit ghash_ce_mod_exit(void) crypto_unregister_aead(&gcm_aes_alg); } -module_cpu_feature_match(PMULL, ghash_ce_mod_init); +static const struct cpu_feature ghash_cpu_feature[] = { + { cpu_feature(PMULL) }, { } +}; +MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature); + +module_init(ghash_ce_mod_init); module_exit(ghash_ce_mod_exit); -- 2.9.3
