1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions 4 * 5 * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org> 6 */ 7 8 #include <linux/cpufeature.h> 9 #include <linux/crc32.h> 10 #include <linux/init.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/string.h> 14 15 #include <crypto/internal/hash.h> 16 #include <crypto/internal/simd.h> 17 18 #include <asm/hwcap.h> 19 #include <asm/neon.h> 20 #include <asm/simd.h> 21 #include <asm/unaligned.h> 22 23 #define PMULL_MIN_LEN 64L /* minimum size of buffer 24 * for crc32_pmull_le_16 */ 25 #define SCALE_F 16L /* size of NEON register */ 26 27 asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc); 28 asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len); 29 30 asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc); 31 asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len); 32 33 static u32 (*fallback_crc32)(u32 init_crc, const u8 buf[], u32 len); 34 static u32 (*fallback_crc32c)(u32 init_crc, const u8 buf[], u32 len); 35 36 static int crc32_cra_init(struct crypto_tfm *tfm) 37 { 38 u32 *key = crypto_tfm_ctx(tfm); 39 40 *key = 0; 41 return 0; 42 } 43 44 static int crc32c_cra_init(struct crypto_tfm *tfm) 45 { 46 u32 *key = crypto_tfm_ctx(tfm); 47 48 *key = ~0; 49 return 0; 50 } 51 52 static int crc32_setkey(struct crypto_shash *hash, const u8 *key, 53 unsigned int keylen) 54 { 55 u32 *mctx = crypto_shash_ctx(hash); 56 57 if (keylen != sizeof(u32)) 58 return -EINVAL; 59 *mctx = le32_to_cpup((__le32 *)key); 60 return 0; 61 } 62 63 static int crc32_init(struct shash_desc *desc) 64 { 65 u32 *mctx = crypto_shash_ctx(desc->tfm); 66 u32 *crc = shash_desc_ctx(desc); 67 68 *crc = *mctx; 69 return 0; 70 } 71 72 static int crc32_update(struct shash_desc *desc, const u8 *data, 73 unsigned int length) 74 { 75 u32 *crc = shash_desc_ctx(desc); 76 77 *crc = crc32_armv8_le(*crc, data, length); 78 return 0; 79 } 80 81 static int crc32c_update(struct shash_desc *desc, const u8 *data, 82 unsigned int length) 83 { 84 u32 *crc = shash_desc_ctx(desc); 85 86 *crc = crc32c_armv8_le(*crc, data, length); 87 return 0; 88 } 89 90 static int crc32_final(struct shash_desc *desc, u8 *out) 91 { 92 u32 *crc = shash_desc_ctx(desc); 93 94 put_unaligned_le32(*crc, out); 95 return 0; 96 } 97 98 static int crc32c_final(struct shash_desc *desc, u8 *out) 99 { 100 u32 *crc = shash_desc_ctx(desc); 101 102 put_unaligned_le32(~*crc, out); 103 return 0; 104 } 105 106 static int crc32_pmull_update(struct shash_desc *desc, const u8 *data, 107 unsigned int length) 108 { 109 u32 *crc = shash_desc_ctx(desc); 110 unsigned int l; 111 112 if (crypto_simd_usable()) { 113 if ((u32)data % SCALE_F) { 114 l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F)); 115 116 *crc = fallback_crc32(*crc, data, l); 117 118 data += l; 119 length -= l; 120 } 121 122 if (length >= PMULL_MIN_LEN) { 123 l = round_down(length, SCALE_F); 124 125 kernel_neon_begin(); 126 *crc = crc32_pmull_le(data, l, *crc); 127 kernel_neon_end(); 128 129 data += l; 130 length -= l; 131 } 132 } 133 134 if (length > 0) 135 *crc = fallback_crc32(*crc, data, length); 136 137 return 0; 138 } 139 140 static int crc32c_pmull_update(struct shash_desc *desc, const u8 *data, 141 unsigned int length) 142 { 143 u32 *crc = shash_desc_ctx(desc); 144 unsigned int l; 145 146 if (crypto_simd_usable()) { 147 if ((u32)data % SCALE_F) { 148 l = min_t(u32, length, SCALE_F - ((u32)data % SCALE_F)); 149 150 *crc = fallback_crc32c(*crc, data, l); 151 152 data += l; 153 length -= l; 154 } 155 156 if (length >= PMULL_MIN_LEN) { 157 l = round_down(length, SCALE_F); 158 159 kernel_neon_begin(); 160 *crc = crc32c_pmull_le(data, l, *crc); 161 kernel_neon_end(); 162 163 data += l; 164 length -= l; 165 } 166 } 167 168 if (length > 0) 169 *crc = fallback_crc32c(*crc, data, length); 170 171 return 0; 172 } 173 174 static struct shash_alg crc32_pmull_algs[] = { { 175 .setkey = crc32_setkey, 176 .init = crc32_init, 177 .update = crc32_update, 178 .final = crc32_final, 179 .descsize = sizeof(u32), 180 .digestsize = sizeof(u32), 181 182 .base.cra_ctxsize = sizeof(u32), 183 .base.cra_init = crc32_cra_init, 184 .base.cra_name = "crc32", 185 .base.cra_driver_name = "crc32-arm-ce", 186 .base.cra_priority = 200, 187 .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 188 .base.cra_blocksize = 1, 189 .base.cra_module = THIS_MODULE, 190 }, { 191 .setkey = crc32_setkey, 192 .init = crc32_init, 193 .update = crc32c_update, 194 .final = crc32c_final, 195 .descsize = sizeof(u32), 196 .digestsize = sizeof(u32), 197 198 .base.cra_ctxsize = sizeof(u32), 199 .base.cra_init = crc32c_cra_init, 200 .base.cra_name = "crc32c", 201 .base.cra_driver_name = "crc32c-arm-ce", 202 .base.cra_priority = 200, 203 .base.cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 204 .base.cra_blocksize = 1, 205 .base.cra_module = THIS_MODULE, 206 } }; 207 208 static int __init crc32_pmull_mod_init(void) 209 { 210 if (elf_hwcap2 & HWCAP2_PMULL) { 211 crc32_pmull_algs[0].update = crc32_pmull_update; 212 crc32_pmull_algs[1].update = crc32c_pmull_update; 213 214 if (elf_hwcap2 & HWCAP2_CRC32) { 215 fallback_crc32 = crc32_armv8_le; 216 fallback_crc32c = crc32c_armv8_le; 217 } else { 218 fallback_crc32 = crc32_le; 219 fallback_crc32c = __crc32c_le; 220 } 221 } else if (!(elf_hwcap2 & HWCAP2_CRC32)) { 222 return -ENODEV; 223 } 224 225 return crypto_register_shashes(crc32_pmull_algs, 226 ARRAY_SIZE(crc32_pmull_algs)); 227 } 228 229 static void __exit crc32_pmull_mod_exit(void) 230 { 231 crypto_unregister_shashes(crc32_pmull_algs, 232 ARRAY_SIZE(crc32_pmull_algs)); 233 } 234 235 static const struct cpu_feature __maybe_unused crc32_cpu_feature[] = { 236 { cpu_feature(CRC32) }, { cpu_feature(PMULL) }, { } 237 }; 238 MODULE_DEVICE_TABLE(cpu, crc32_cpu_feature); 239 240 module_init(crc32_pmull_mod_init); 241 module_exit(crc32_pmull_mod_exit); 242 243 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>"); 244 MODULE_LICENSE("GPL v2"); 245 MODULE_ALIAS_CRYPTO("crc32"); 246 MODULE_ALIAS_CRYPTO("crc32c"); 247