diff options
Diffstat (limited to 'lib/crypto/x86/poly1305_glue.c')
| -rw-r--r-- | lib/crypto/x86/poly1305_glue.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/lib/crypto/x86/poly1305_glue.c b/lib/crypto/x86/poly1305_glue.c new file mode 100644 index 000000000000..856d48fd422b --- /dev/null +++ b/lib/crypto/x86/poly1305_glue.c @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#include <asm/cpu_device_id.h> +#include <asm/fpu/api.h> +#include <crypto/internal/poly1305.h> +#include <linux/jump_label.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/sizes.h> +#include <linux/unaligned.h> + +struct poly1305_arch_internal { + union { + struct { + u32 h[5]; + u32 is_base2_26; + }; + u64 hs[3]; + }; + u64 r[2]; + u64 pad; + struct { u32 r2, r1, r4, r3; } rn[9]; +}; + +/* + * The AVX code uses base 2^26, while the scalar code uses base 2^64. If we hit + * the unfortunate situation of using AVX and then having to go back to scalar + * -- because the user is silly and has called the update function from two + * separate contexts -- then we need to convert back to the original base before + * proceeding. It is possible to reason that the initial reduction below is + * sufficient given the implementation invariants. However, for an avoidance of + * doubt and because this is not performance critical, we do the full reduction + * anyway. Z3 proof of below function: https://xn--4db.cc/ltPtHCKN/py + */ +static void convert_to_base2_64(void *ctx) +{ + struct poly1305_arch_internal *state = ctx; + u32 cy; + + if (!state->is_base2_26) + return; + + cy = state->h[0] >> 26; state->h[0] &= 0x3ffffff; state->h[1] += cy; + cy = state->h[1] >> 26; state->h[1] &= 0x3ffffff; state->h[2] += cy; + cy = state->h[2] >> 26; state->h[2] &= 0x3ffffff; state->h[3] += cy; + cy = state->h[3] >> 26; state->h[3] &= 0x3ffffff; state->h[4] += cy; + state->hs[0] = ((u64)state->h[2] << 52) | ((u64)state->h[1] << 26) | state->h[0]; + state->hs[1] = ((u64)state->h[4] << 40) | ((u64)state->h[3] << 14) | (state->h[2] >> 12); + state->hs[2] = state->h[4] >> 24; + /* Unsigned Less Than: branchlessly produces 1 if a < b, else 0. */ +#define ULT(a, b) ((a ^ ((a ^ b) | ((a - b) ^ b))) >> (sizeof(a) * 8 - 1)) + cy = (state->hs[2] >> 2) + (state->hs[2] & ~3ULL); + state->hs[2] &= 3; + state->hs[0] += cy; + state->hs[1] += (cy = ULT(state->hs[0], cy)); + state->hs[2] += ULT(state->hs[1], cy); +#undef ULT + state->is_base2_26 = 0; +} + +asmlinkage void poly1305_block_init_arch( + struct poly1305_block_state *state, + const u8 raw_key[POLY1305_BLOCK_SIZE]); +EXPORT_SYMBOL_GPL(poly1305_block_init_arch); +asmlinkage void poly1305_blocks_x86_64(struct poly1305_arch_internal *ctx, + const u8 *inp, + const size_t len, const u32 padbit); +asmlinkage void poly1305_emit_x86_64(const struct poly1305_state *ctx, + u8 mac[POLY1305_DIGEST_SIZE], + const u32 nonce[4]); +asmlinkage void poly1305_emit_avx(const struct poly1305_state *ctx, + u8 mac[POLY1305_DIGEST_SIZE], + const u32 nonce[4]); +asmlinkage void poly1305_blocks_avx(struct poly1305_arch_internal *ctx, + const u8 *inp, const size_t len, + const u32 padbit); +asmlinkage void poly1305_blocks_avx2(struct poly1305_arch_internal *ctx, + const u8 *inp, const size_t len, + const u32 padbit); +asmlinkage void poly1305_blocks_avx512(struct poly1305_arch_internal *ctx, + const u8 *inp, + const size_t len, const u32 padbit); + +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx); +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx2); +static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx512); + +void poly1305_blocks_arch(struct poly1305_block_state *state, const u8 *inp, + unsigned int len, u32 padbit) +{ + struct poly1305_arch_internal *ctx = + container_of(&state->h.h, struct poly1305_arch_internal, h); + + /* SIMD disables preemption, so relax after processing each page. */ + BUILD_BUG_ON(SZ_4K < POLY1305_BLOCK_SIZE || + SZ_4K % POLY1305_BLOCK_SIZE); + + /* + * The AVX implementations have significant setup overhead (e.g. key + * power computation, kernel FPU enabling) which makes them slower for + * short messages. Fall back to the scalar implementation for messages + * shorter than 288 bytes, unless the AVX-specific key setup has already + * been performed (indicated by ctx->is_base2_26). + */ + if (!static_branch_likely(&poly1305_use_avx) || + (len < POLY1305_BLOCK_SIZE * 18 && !ctx->is_base2_26) || + unlikely(!irq_fpu_usable())) { + convert_to_base2_64(ctx); + poly1305_blocks_x86_64(ctx, inp, len, padbit); + return; + } + + do { + const unsigned int bytes = min(len, SZ_4K); + + kernel_fpu_begin(); + if (static_branch_likely(&poly1305_use_avx512)) + poly1305_blocks_avx512(ctx, inp, bytes, padbit); + else if (static_branch_likely(&poly1305_use_avx2)) + poly1305_blocks_avx2(ctx, inp, bytes, padbit); + else + poly1305_blocks_avx(ctx, inp, bytes, padbit); + kernel_fpu_end(); + + len -= bytes; + inp += bytes; + } while (len); +} +EXPORT_SYMBOL_GPL(poly1305_blocks_arch); + +void poly1305_emit_arch(const struct poly1305_state *ctx, + u8 mac[POLY1305_DIGEST_SIZE], const u32 nonce[4]) +{ + if (!static_branch_likely(&poly1305_use_avx)) + poly1305_emit_x86_64(ctx, mac, nonce); + else + poly1305_emit_avx(ctx, mac, nonce); +} +EXPORT_SYMBOL_GPL(poly1305_emit_arch); + +bool poly1305_is_arch_optimized(void) +{ + return static_key_enabled(&poly1305_use_avx); +} +EXPORT_SYMBOL(poly1305_is_arch_optimized); + +static int __init poly1305_simd_mod_init(void) +{ + if (boot_cpu_has(X86_FEATURE_AVX) && + cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) + static_branch_enable(&poly1305_use_avx); + if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) && + cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) + static_branch_enable(&poly1305_use_avx2); + if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_AVX2) && + boot_cpu_has(X86_FEATURE_AVX512F) && + cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM | XFEATURE_MASK_AVX512, NULL) && + /* Skylake downclocks unacceptably much when using zmm, but later generations are fast. */ + boot_cpu_data.x86_vfm != INTEL_SKYLAKE_X) + static_branch_enable(&poly1305_use_avx512); + return 0; +} +subsys_initcall(poly1305_simd_mod_init); + +static void __exit poly1305_simd_mod_exit(void) +{ +} +module_exit(poly1305_simd_mod_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>"); +MODULE_DESCRIPTION("Poly1305 authenticator"); |