arch/x86/crypto/crc32c-intel.c

   1 /*
   2  * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
   3  * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
   4  * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
   5  * http://www.intel.com/products/processor/manuals/
   6  * Intel(R) 64 and IA-32 Architectures Software Developer's Manual
   7  * Volume 2A: Instruction Set Reference, A-M
   8  *
   9  * Copyright (C) 2008 Intel Corporation
  10  * Authors: Austin Zhang <austin_zhang@linux.intel.com>
  11  *          Kent Liu <kent.liu@intel.com>
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms and conditions of the GNU General Public License,
  15  * version 2, as published by the Free Software Foundation.
  16  *
  17  * This program is distributed in the hope it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  20  * more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along with
  23  * this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  25  *
  26  */
  27 #include <linux/init.h>
  28 #include <linux/module.h>
  29 #include <linux/string.h>
  30 #include <linux/kernel.h>
  31 #include <crypto/internal/hash.h>
  32
  33 #include <asm/cpufeature.h>
  34
  35 #define CHKSUM_BLOCK_SIZE       1
  36 #define CHKSUM_DIGEST_SIZE      4
  37
  38 #define SCALE_F sizeof(unsigned long)
  39
  40 #ifdef CONFIG_X86_64
  41 #define REX_PRE "0x48, "
  42 #else
  43 #define REX_PRE
  44 #endif
  45
  46 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
  47 {
  48         while (length--) {
  49                 __asm__ __volatile__(
  50                         ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
  51                         :"=S"(crc)
  52                         :"0"(crc), "c"(*data)
  53                 );
  54                 data++;
  55         }
  56
  57         return crc;
  58 }
  59
  60 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
  61 {
  62         unsigned int iquotient = len / SCALE_F;
  63         unsigned int iremainder = len % SCALE_F;
  64         unsigned long *ptmp = (unsigned long *)p;
  65
  66         while (iquotient--) {
  67                 __asm__ __volatile__(
  68                         ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
  69                         :"=S"(crc)
  70                         :"0"(crc), "c"(*ptmp)
  71                 );
  72                 ptmp++;
  73         }
  74
  75         if (iremainder)
  76                 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
  77                                  iremainder);
  78
  79         return crc;
  80 }
  81
  82 /*
  83  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  84  * If your algorithm starts with ~0, then XOR with ~0 before you set
  85  * the seed.
  86  */
  87 static int crc32c_intel_setkey(struct crypto_ahash *hash, const u8 *key,
  88                         unsigned int keylen)
  89 {
  90         u32 *mctx = crypto_ahash_ctx(hash);
  91
  92         if (keylen != sizeof(u32)) {
  93                 crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  94                 return -EINVAL;
  95         }
  96         *mctx = le32_to_cpup((__le32 *)key);
  97         return 0;
  98 }
  99
 100 static int crc32c_intel_init(struct ahash_request *req)
 101 {
 102         u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 103         u32 *crcp = ahash_request_ctx(req);
 104
 105         *crcp = *mctx;
 106
 107         return 0;
 108 }
 109
 110 static int crc32c_intel_update(struct ahash_request *req)
 111 {
 112         struct crypto_hash_walk walk;
 113         u32 *crcp = ahash_request_ctx(req);
 114         u32 crc = *crcp;
 115         int nbytes;
 116
 117         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
 118            nbytes = crypto_hash_walk_done(&walk, 0))
 119         crc = crc32c_intel_le_hw(crc, walk.data, nbytes);
 120
 121         *crcp = crc;
 122         return 0;
 123 }
 124
 125 static int crc32c_intel_final(struct ahash_request *req)
 126 {
 127         u32 *crcp = ahash_request_ctx(req);
 128
 129         *(__le32 *)req->result = ~cpu_to_le32p(crcp);
 130         return 0;
 131 }
 132
 133 static int crc32c_intel_digest(struct ahash_request *req)
 134 {
 135         struct crypto_hash_walk walk;
 136         u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
 137         u32 crc = *mctx;
 138         int nbytes;
 139
 140         for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
 141            nbytes = crypto_hash_walk_done(&walk, 0))
 142                 crc = crc32c_intel_le_hw(crc, walk.data, nbytes);
 143
 144         *(__le32 *)req->result = ~cpu_to_le32(crc);
 145         return 0;
 146 }
 147
 148 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
 149 {
 150         u32 *key = crypto_tfm_ctx(tfm);
 151
 152         *key = ~0;
 153
 154         tfm->crt_ahash.reqsize = sizeof(u32);
 155
 156         return 0;
 157 }
 158
 159 static struct crypto_alg alg = {
 160         .cra_name               =       "crc32c",
 161         .cra_driver_name        =       "crc32c-intel",
 162         .cra_priority           =       200,
 163         .cra_flags              =       CRYPTO_ALG_TYPE_AHASH,
 164         .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
 165         .cra_alignmask          =       3,
 166         .cra_ctxsize            =       sizeof(u32),
 167         .cra_module             =       THIS_MODULE,
 168         .cra_list               =       LIST_HEAD_INIT(alg.cra_list),
 169         .cra_init               =       crc32c_intel_cra_init,
 170         .cra_type               =       &crypto_ahash_type,
 171         .cra_u                  =       {
 172                 .ahash = {
 173                         .digestsize    =       CHKSUM_DIGEST_SIZE,
 174                         .setkey        =       crc32c_intel_setkey,
 175                         .init          =       crc32c_intel_init,
 176                         .update        =       crc32c_intel_update,
 177                         .final         =       crc32c_intel_final,
 178                         .digest        =       crc32c_intel_digest,
 179                 }
 180         }
 181 };
 182
 183
 184 static int __init crc32c_intel_mod_init(void)
 185 {
 186         if (cpu_has_xmm4_2)
 187                 return crypto_register_alg(&alg);
 188         else
 189                 return -ENODEV;
 190 }
 191
 192 static void __exit crc32c_intel_mod_fini(void)
 193 {
 194         crypto_unregister_alg(&alg);
 195 }
 196
 197 module_init(crc32c_intel_mod_init);
 198 module_exit(crc32c_intel_mod_fini);
 199
 200 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
 201 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 202 MODULE_LICENSE("GPL");
 203
 204 MODULE_ALIAS("crc32c");
 205 MODULE_ALIAS("crc32c-intel");