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/neon.h> 8 #include <asm/simd.h> 9 #include <linux/cpufeature.h> 10 11 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon); 12 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce); 13 14 asmlinkage void sha256_block_data_order(struct sha256_block_state *state, 15 const u8 *data, size_t nblocks); 16 asmlinkage void sha256_block_neon(struct sha256_block_state *state, 17 const u8 *data, size_t nblocks); 18 asmlinkage size_t __sha256_ce_transform(struct sha256_block_state *state, 19 const u8 *data, size_t nblocks); 20 21 static void sha256_blocks(struct sha256_block_state *state, 22 const u8 *data, size_t nblocks) 23 { 24 if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && 25 static_branch_likely(&have_neon) && likely(may_use_simd())) { 26 if (static_branch_likely(&have_ce)) { 27 do { 28 size_t rem; 29 30 kernel_neon_begin(); 31 rem = __sha256_ce_transform(state, 32 data, nblocks); 33 kernel_neon_end(); 34 data += (nblocks - rem) * SHA256_BLOCK_SIZE; 35 nblocks = rem; 36 } while (nblocks); 37 } else { 38 kernel_neon_begin(); 39 sha256_block_neon(state, data, nblocks); 40 kernel_neon_end(); 41 } 42 } else { 43 sha256_block_data_order(state, data, nblocks); 44 } 45 } 46 47 static_assert(offsetof(struct __sha256_ctx, state) == 0); 48 static_assert(offsetof(struct __sha256_ctx, bytecount) == 32); 49 static_assert(offsetof(struct __sha256_ctx, buf) == 40); 50 asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx, 51 const u8 *data1, const u8 *data2, int len, 52 u8 out1[SHA256_DIGEST_SIZE], 53 u8 out2[SHA256_DIGEST_SIZE]); 54 55 #define sha256_finup_2x_arch sha256_finup_2x_arch 56 static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx, 57 const u8 *data1, const u8 *data2, size_t len, 58 u8 out1[SHA256_DIGEST_SIZE], 59 u8 out2[SHA256_DIGEST_SIZE]) 60 { 61 /* 62 * The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX. 63 * Further limit len to 65536 to avoid spending too long with preemption 64 * disabled. (Of course, in practice len is nearly always 4096 anyway.) 65 */ 66 if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && 67 static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE && 68 len <= 65536 && likely(may_use_simd())) { 69 kernel_neon_begin(); 70 sha256_ce_finup2x(ctx, data1, data2, len, out1, out2); 71 kernel_neon_end(); 72 kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE); 73 kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE); 74 return true; 75 } 76 return false; 77 } 78 79 static bool sha256_finup_2x_is_optimized_arch(void) 80 { 81 return static_key_enabled(&have_ce); 82 } 83 84 #ifdef CONFIG_KERNEL_MODE_NEON 85 #define sha256_mod_init_arch sha256_mod_init_arch 86 static void sha256_mod_init_arch(void) 87 { 88 if (cpu_have_named_feature(ASIMD)) { 89 static_branch_enable(&have_neon); 90 if (cpu_have_named_feature(SHA2)) 91 static_branch_enable(&have_ce); 92 } 93 } 94 #endif /* CONFIG_KERNEL_MODE_NEON */ 95