1 /* GPL HEADER START 2 * 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 only, 7 * as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, but 10 * WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License version 2 for more details (a copy is included 13 * in the LICENSE file that accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License 16 * version 2 along with this program; If not, see http://www.gnu.org/licenses 17 * 18 * Please visit http://www.xyratex.com/contact if you need additional 19 * information or have any questions. 20 * 21 * GPL HEADER END 22 */ 23 24 /* 25 * Copyright 2012 Xyratex Technology Limited 26 * 27 * Wrappers for kernel crypto shash api to pclmulqdq crc32 imlementation. 28 */ 29 #include <linux/init.h> 30 #include <linux/module.h> 31 #include <linux/string.h> 32 #include <linux/kernel.h> 33 #include <linux/crc32.h> 34 #include <crypto/internal/hash.h> 35 #include <crypto/internal/simd.h> 36 37 #include <asm/cpufeatures.h> 38 #include <asm/cpu_device_id.h> 39 #include <asm/simd.h> 40 41 #define CHKSUM_BLOCK_SIZE 1 42 #define CHKSUM_DIGEST_SIZE 4 43 44 #define PCLMUL_MIN_LEN 64L /* minimum size of buffer 45 * for crc32_pclmul_le_16 */ 46 #define SCALE_F 16L /* size of xmm register */ 47 #define SCALE_F_MASK (SCALE_F - 1) 48 49 u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32); 50 51 static u32 __attribute__((pure)) 52 crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len) 53 { 54 unsigned int iquotient; 55 unsigned int iremainder; 56 unsigned int prealign; 57 58 if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !crypto_simd_usable()) 59 return crc32_le(crc, p, len); 60 61 if ((long)p & SCALE_F_MASK) { 62 /* align p to 16 byte */ 63 prealign = SCALE_F - ((long)p & SCALE_F_MASK); 64 65 crc = crc32_le(crc, p, prealign); 66 len -= prealign; 67 p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) & 68 ~SCALE_F_MASK); 69 } 70 iquotient = len & (~SCALE_F_MASK); 71 iremainder = len & SCALE_F_MASK; 72 73 kernel_fpu_begin(); 74 crc = crc32_pclmul_le_16(p, iquotient, crc); 75 kernel_fpu_end(); 76 77 if (iremainder) 78 crc = crc32_le(crc, p + iquotient, iremainder); 79 80 return crc; 81 } 82 83 static int crc32_pclmul_cra_init(struct crypto_tfm *tfm) 84 { 85 u32 *key = crypto_tfm_ctx(tfm); 86 87 *key = 0; 88 89 return 0; 90 } 91 92 static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key, 93 unsigned int keylen) 94 { 95 u32 *mctx = crypto_shash_ctx(hash); 96 97 if (keylen != sizeof(u32)) { 98 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); 99 return -EINVAL; 100 } 101 *mctx = le32_to_cpup((__le32 *)key); 102 return 0; 103 } 104 105 static int crc32_pclmul_init(struct shash_desc *desc) 106 { 107 u32 *mctx = crypto_shash_ctx(desc->tfm); 108 u32 *crcp = shash_desc_ctx(desc); 109 110 *crcp = *mctx; 111 112 return 0; 113 } 114 115 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data, 116 unsigned int len) 117 { 118 u32 *crcp = shash_desc_ctx(desc); 119 120 *crcp = crc32_pclmul_le(*crcp, data, len); 121 return 0; 122 } 123 124 /* No final XOR 0xFFFFFFFF, like crc32_le */ 125 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len, 126 u8 *out) 127 { 128 *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len)); 129 return 0; 130 } 131 132 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data, 133 unsigned int len, u8 *out) 134 { 135 return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out); 136 } 137 138 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out) 139 { 140 u32 *crcp = shash_desc_ctx(desc); 141 142 *(__le32 *)out = cpu_to_le32p(crcp); 143 return 0; 144 } 145 146 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data, 147 unsigned int len, u8 *out) 148 { 149 return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len, 150 out); 151 } 152 153 static struct shash_alg alg = { 154 .setkey = crc32_pclmul_setkey, 155 .init = crc32_pclmul_init, 156 .update = crc32_pclmul_update, 157 .final = crc32_pclmul_final, 158 .finup = crc32_pclmul_finup, 159 .digest = crc32_pclmul_digest, 160 .descsize = sizeof(u32), 161 .digestsize = CHKSUM_DIGEST_SIZE, 162 .base = { 163 .cra_name = "crc32", 164 .cra_driver_name = "crc32-pclmul", 165 .cra_priority = 200, 166 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 167 .cra_blocksize = CHKSUM_BLOCK_SIZE, 168 .cra_ctxsize = sizeof(u32), 169 .cra_module = THIS_MODULE, 170 .cra_init = crc32_pclmul_cra_init, 171 } 172 }; 173 174 static const struct x86_cpu_id crc32pclmul_cpu_id[] = { 175 X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ), 176 {} 177 }; 178 MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id); 179 180 181 static int __init crc32_pclmul_mod_init(void) 182 { 183 184 if (!x86_match_cpu(crc32pclmul_cpu_id)) { 185 pr_info("PCLMULQDQ-NI instructions are not detected.\n"); 186 return -ENODEV; 187 } 188 return crypto_register_shash(&alg); 189 } 190 191 static void __exit crc32_pclmul_mod_fini(void) 192 { 193 crypto_unregister_shash(&alg); 194 } 195 196 module_init(crc32_pclmul_mod_init); 197 module_exit(crc32_pclmul_mod_fini); 198 199 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 200 MODULE_LICENSE("GPL"); 201 202 MODULE_ALIAS_CRYPTO("crc32"); 203 MODULE_ALIAS_CRYPTO("crc32-pclmul"); 204