arch/x86/crypto/crc32-pclmul_glue.c

   1 /* GPL HEADER START
   2  *
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
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   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");