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
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  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");