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