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  *
   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");