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 (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && 24 static_branch_likely(&have_neon) && likely(may_use_simd())) { 25 if (static_branch_likely(&have_ce)) { 26 do { 27 size_t rem; 28 29 scoped_ksimd() 30 rem = __sha256_ce_transform(state, data, 31 nblocks); 32 33 data += (nblocks - rem) * SHA256_BLOCK_SIZE; 34 nblocks = rem; 35 } while (nblocks); 36 } else { 37 scoped_ksimd() 38 sha256_block_neon(state, data, nblocks); 39 } 40 } else { 41 sha256_block_data_order(state, data, nblocks); 42 } 43 } 44 45 static_assert(offsetof(struct __sha256_ctx, state) == 0); 46 static_assert(offsetof(struct __sha256_ctx, bytecount) == 32); 47 static_assert(offsetof(struct __sha256_ctx, buf) == 40); 48 asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx, 49 const u8 *data1, const u8 *data2, int len, 50 u8 out1[SHA256_DIGEST_SIZE], 51 u8 out2[SHA256_DIGEST_SIZE]); 52 53 #define sha256_finup_2x_arch sha256_finup_2x_arch 54 static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx, 55 const u8 *data1, const u8 *data2, size_t len, 56 u8 out1[SHA256_DIGEST_SIZE], 57 u8 out2[SHA256_DIGEST_SIZE]) 58 { 59 /* 60 * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX. 61 * Further limit len to 65536 to avoid spending too long with preemption 62 * disabled. (Of course, in practice len is nearly always 4096 anyway.) 63 */ 64 if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && 65 static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE && 66 len <= 65536 && likely(may_use_simd())) { 67 scoped_ksimd() 68 sha256_ce_finup2x(ctx, data1, data2, len, out1, out2); 69 kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE); 70 kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE); 71 return true; 72 } 73 return false; 74 } 75 76 static bool sha256_finup_2x_is_optimized_arch(void) 77 { 78 return static_key_enabled(&have_ce); 79 } 80 81 #ifdef CONFIG_KERNEL_MODE_NEON 82 #define sha256_mod_init_arch sha256_mod_init_arch 83 static void sha256_mod_init_arch(void) 84 { 85 if (cpu_have_named_feature(ASIMD)) { 86 static_branch_enable(&have_neon); 87 if (cpu_have_named_feature(SHA2)) 88 static_branch_enable(&have_ce); 89 } 90 } 91 #endif /* CONFIG_KERNEL_MODE_NEON */ 92