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 36 #include <asm/cpufeatures.h> 37 #include <asm/cpu_device_id.h> 38 #include <asm/fpu/api.h> 39 40 #define CHKSUM_BLOCK_SIZE 1 41 #define CHKSUM_DIGEST_SIZE 4 42 43 #define PCLMUL_MIN_LEN 64L /* minimum size of buffer 44 * for crc32_pclmul_le_16 */ 45 #define SCALE_F 16L /* size of xmm register */ 46 #define SCALE_F_MASK (SCALE_F - 1) 47 48 u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32); 49 50 static u32 __attribute__((pure)) 51 crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len) 52 { 53 unsigned int iquotient; 54 unsigned int iremainder; 55 unsigned int prealign; 56 57 if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !irq_fpu_usable()) 58 return crc32_le(crc, p, len); 59 60 if ((long)p & SCALE_F_MASK) { 61 /* align p to 16 byte */ 62 prealign = SCALE_F - ((long)p & SCALE_F_MASK); 63 64 crc = crc32_le(crc, p, prealign); 65 len -= prealign; 66 p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) & 67 ~SCALE_F_MASK); 68 } 69 iquotient = len & (~SCALE_F_MASK); 70 iremainder = len & SCALE_F_MASK; 71 72 kernel_fpu_begin(); 73 crc = crc32_pclmul_le_16(p, iquotient, crc); 74 kernel_fpu_end(); 75 76 if (iremainder) 77 crc = crc32_le(crc, p + iquotient, iremainder); 78 79 return crc; 80 } 81 82 static int crc32_pclmul_cra_init(struct crypto_tfm *tfm) 83 { 84 u32 *key = crypto_tfm_ctx(tfm); 85 86 *key = 0; 87 88 return 0; 89 } 90 91 static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key, 92 unsigned int keylen) 93 { 94 u32 *mctx = crypto_shash_ctx(hash); 95 96 if (keylen != sizeof(u32)) { 97 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); 98 return -EINVAL; 99 } 100 *mctx = le32_to_cpup((__le32 *)key); 101 return 0; 102 } 103 104 static int crc32_pclmul_init(struct shash_desc *desc) 105 { 106 u32 *mctx = crypto_shash_ctx(desc->tfm); 107 u32 *crcp = shash_desc_ctx(desc); 108 109 *crcp = *mctx; 110 111 return 0; 112 } 113 114 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data, 115 unsigned int len) 116 { 117 u32 *crcp = shash_desc_ctx(desc); 118 119 *crcp = crc32_pclmul_le(*crcp, data, len); 120 return 0; 121 } 122 123 /* No final XOR 0xFFFFFFFF, like crc32_le */ 124 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len, 125 u8 *out) 126 { 127 *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len)); 128 return 0; 129 } 130 131 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data, 132 unsigned int len, u8 *out) 133 { 134 return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out); 135 } 136 137 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out) 138 { 139 u32 *crcp = shash_desc_ctx(desc); 140 141 *(__le32 *)out = cpu_to_le32p(crcp); 142 return 0; 143 } 144 145 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data, 146 unsigned int len, u8 *out) 147 { 148 return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len, 149 out); 150 } 151 152 static struct shash_alg alg = { 153 .setkey = crc32_pclmul_setkey, 154 .init = crc32_pclmul_init, 155 .update = crc32_pclmul_update, 156 .final = crc32_pclmul_final, 157 .finup = crc32_pclmul_finup, 158 .digest = crc32_pclmul_digest, 159 .descsize = sizeof(u32), 160 .digestsize = CHKSUM_DIGEST_SIZE, 161 .base = { 162 .cra_name = "crc32", 163 .cra_driver_name = "crc32-pclmul", 164 .cra_priority = 200, 165 .cra_blocksize = CHKSUM_BLOCK_SIZE, 166 .cra_ctxsize = sizeof(u32), 167 .cra_module = THIS_MODULE, 168 .cra_init = crc32_pclmul_cra_init, 169 } 170 }; 171 172 static const struct x86_cpu_id crc32pclmul_cpu_id[] = { 173 X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ), 174 {} 175 }; 176 MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id); 177 178 179 static int __init crc32_pclmul_mod_init(void) 180 { 181 182 if (!x86_match_cpu(crc32pclmul_cpu_id)) { 183 pr_info("PCLMULQDQ-NI instructions are not detected.\n"); 184 return -ENODEV; 185 } 186 return crypto_register_shash(&alg); 187 } 188 189 static void __exit crc32_pclmul_mod_fini(void) 190 { 191 crypto_unregister_shash(&alg); 192 } 193 194 module_init(crc32_pclmul_mod_init); 195 module_exit(crc32_pclmul_mod_fini); 196 197 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>"); 198 MODULE_LICENSE("GPL"); 199 200 MODULE_ALIAS_CRYPTO("crc32"); 201 MODULE_ALIAS_CRYPTO("crc32-pclmul"); 202