/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * SHA-256 optimized for x86_64 * * Copyright 2025 Google LLC */ #include #include static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha_ni); DEFINE_STATIC_CALL(sha256_blocks_x86, sha256_blocks_generic); #define DEFINE_X86_SHA256_FN(c_fn, asm_fn) \ asmlinkage void asm_fn(struct sha256_block_state *state, \ const u8 *data, size_t nblocks); \ static void c_fn(struct sha256_block_state *state, const u8 *data, \ size_t nblocks) \ { \ if (likely(irq_fpu_usable())) { \ kernel_fpu_begin(); \ asm_fn(state, data, nblocks); \ kernel_fpu_end(); \ } else { \ sha256_blocks_generic(state, data, nblocks); \ } \ } DEFINE_X86_SHA256_FN(sha256_blocks_ssse3, sha256_transform_ssse3); DEFINE_X86_SHA256_FN(sha256_blocks_avx, sha256_transform_avx); DEFINE_X86_SHA256_FN(sha256_blocks_avx2, sha256_transform_rorx); DEFINE_X86_SHA256_FN(sha256_blocks_ni, sha256_ni_transform); static void sha256_blocks(struct sha256_block_state *state, const u8 *data, size_t nblocks) { static_call(sha256_blocks_x86)(state, data, nblocks); } static_assert(offsetof(struct __sha256_ctx, state) == 0); static_assert(offsetof(struct __sha256_ctx, bytecount) == 32); static_assert(offsetof(struct __sha256_ctx, buf) == 40); asmlinkage void sha256_ni_finup2x(const struct __sha256_ctx *ctx, const u8 *data1, const u8 *data2, int len, u8 out1[SHA256_DIGEST_SIZE], u8 out2[SHA256_DIGEST_SIZE]); #define sha256_finup_2x_arch sha256_finup_2x_arch static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx, const u8 *data1, const u8 *data2, size_t len, u8 out1[SHA256_DIGEST_SIZE], u8 out2[SHA256_DIGEST_SIZE]) { /* * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX. * Further limit len to 65536 to avoid spending too long with preemption * disabled. (Of course, in practice len is nearly always 4096 anyway.) */ if (static_branch_likely(&have_sha_ni) && len >= SHA256_BLOCK_SIZE && len <= 65536 && likely(irq_fpu_usable())) { kernel_fpu_begin(); sha256_ni_finup2x(ctx, data1, data2, len, out1, out2); kernel_fpu_end(); kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE); kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE); return true; } return false; } static bool sha256_finup_2x_is_optimized_arch(void) { return static_key_enabled(&have_sha_ni); } #define sha256_mod_init_arch sha256_mod_init_arch static void sha256_mod_init_arch(void) { if (boot_cpu_has(X86_FEATURE_SHA_NI)) { static_call_update(sha256_blocks_x86, sha256_blocks_ni); static_branch_enable(&have_sha_ni); } else if (cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL) && boot_cpu_has(X86_FEATURE_AVX)) { if (boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_BMI2)) static_call_update(sha256_blocks_x86, sha256_blocks_avx2); else static_call_update(sha256_blocks_x86, sha256_blocks_avx); } else if (boot_cpu_has(X86_FEATURE_SSSE3)) { static_call_update(sha256_blocks_x86, sha256_blocks_ssse3); } }