1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * SHA-256 optimized for ARM64 4 * 5 * Copyright 2025 Google LLC 6 */ 7 #include <asm/simd.h> 8 #include <linux/cpufeature.h> 9 10 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon); 11 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce); 12 13 asmlinkage void sha256_block_data_order(struct sha256_block_state *state, 14 const u8 *data, size_t nblocks); 15 asmlinkage void sha256_block_neon(struct sha256_block_state *state, 16 const u8 *data, size_t nblocks); 17 asmlinkage size_t __sha256_ce_transform(struct sha256_block_state *state, 18 const u8 *data, size_t nblocks); 19 20 static void sha256_blocks(struct sha256_block_state *state, 21 const u8 *data, size_t nblocks) 22 { 23 if (static_branch_likely(&have_neon) && likely(may_use_simd())) { 24 if (static_branch_likely(&have_ce)) { 25 do { 26 size_t rem; 27 28 scoped_ksimd() 29 rem = __sha256_ce_transform(state, data, 30 nblocks); 31 32 data += (nblocks - rem) * SHA256_BLOCK_SIZE; 33 nblocks = rem; 34 } while (nblocks); 35 } else { 36 scoped_ksimd() 37 sha256_block_neon(state, data, nblocks); 38 } 39 } else { 40 sha256_block_data_order(state, data, nblocks); 41 } 42 } 43 44 static_assert(offsetof(struct __sha256_ctx, state) == 0); 45 static_assert(offsetof(struct __sha256_ctx, bytecount) == 32); 46 static_assert(offsetof(struct __sha256_ctx, buf) == 40); 47 asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx, 48 const u8 *data1, const u8 *data2, int len, 49 u8 out1[SHA256_DIGEST_SIZE], 50 u8 out2[SHA256_DIGEST_SIZE]); 51 52 #define sha256_finup_2x_arch sha256_finup_2x_arch 53 static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx, 54 const u8 *data1, const u8 *data2, size_t len, 55 u8 out1[SHA256_DIGEST_SIZE], 56 u8 out2[SHA256_DIGEST_SIZE]) 57 { 58 /* 59 * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX. 60 * Further limit len to 65536 to avoid spending too long with preemption 61 * disabled. (Of course, in practice len is nearly always 4096 anyway.) 62 */ 63 if (static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE && 64 len <= 65536 && likely(may_use_simd())) { 65 scoped_ksimd() 66 sha256_ce_finup2x(ctx, data1, data2, len, out1, out2); 67 kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE); 68 kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE); 69 return true; 70 } 71 return false; 72 } 73 74 static bool sha256_finup_2x_is_optimized_arch(void) 75 { 76 return static_key_enabled(&have_ce); 77 } 78 79 #define sha256_mod_init_arch sha256_mod_init_arch 80 static void sha256_mod_init_arch(void) 81 { 82 if (cpu_have_named_feature(ASIMD)) { 83 static_branch_enable(&have_neon); 84 if (cpu_have_named_feature(SHA2)) 85 static_branch_enable(&have_ce); 86 } 87 } 88