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 implementation. 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 return -EINVAL; 99 *mctx = le32_to_cpup((__le32 *)key); 100 return 0; 101 } 102 103 static int crc32_pclmul_init(struct shash_desc *desc) 104 { 105 u32 *mctx = crypto_shash_ctx(desc->tfm); 106 u32 *crcp = shash_desc_ctx(desc); 107 108 *crcp = *mctx; 109 110 return 0; 111 } 112 113 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data, 114 unsigned int len) 115 { 116 u32 *crcp = shash_desc_ctx(desc); 117 118 *crcp = crc32_pclmul_le(*crcp, data, len); 119 return 0; 120 } 121 122 /* No final XOR 0xFFFFFFFF, like crc32_le */ 123 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len, 124 u8 *out) 125 { 126 *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len)); 127 return 0; 128 } 129 130 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data, 131 unsigned int len, u8 *out) 132 { 133 return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out); 134 } 135 136 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out) 137 { 138 u32 *crcp = shash_desc_ctx(desc); 139 140 *(__le32 *)out = cpu_to_le32p(crcp); 141 return 0; 142 } 143 144 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data, 145 unsigned int len, u8 *out) 146 { 147 return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len, 148 out); 149 } 150 151 static struct shash_alg alg = { 152 .setkey = crc32_pclmul_setkey, 153 .init = crc32_pclmul_init, 154 .update = crc32_pclmul_update, 155 .final = crc32_pclmul_final, 156 .finup = crc32_pclmul_finup, 157 .digest = crc32_pclmul_digest, 158 .descsize = sizeof(u32), 159 .digestsize = CHKSUM_DIGEST_SIZE, 160 .base = { 161 .cra_name = "crc32", 162 .cra_driver_name = "crc32-pclmul", 163 .cra_priority = 200, 164 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY, 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_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL), 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