git.oblomov.eu Git - linux-2.6/blob - 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_shash *hash, const u8 *key,
  88                         unsigned int keylen)
  89 {
  90         u32 *mctx = crypto_shash_ctx(hash);
  91
  92         if (keylen != sizeof(u32)) {
  93                 crypto_shash_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 shash_desc *desc)
 101 {
 102         u32 *mctx = crypto_shash_ctx(desc->tfm);
 103         u32 *crcp = shash_desc_ctx(desc);
 104
 105         *crcp = *mctx;
 106
 107         return 0;
 108 }
 109
 110 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
 111                                unsigned int len)
 112 {
 113         u32 *crcp = shash_desc_ctx(desc);
 114
 115         *crcp = crc32c_intel_le_hw(*crcp, data, len);
 116         return 0;
 117 }
 118
 119 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 120                                 u8 *out)
 121 {
 122         *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 123         return 0;
 124 }
 125
 126 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
 127                               unsigned int len, u8 *out)
 128 {
 129         return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
 130 }
 131
 132 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
 133 {
 134         u32 *crcp = shash_desc_ctx(desc);
 135
 136         *(__le32 *)out = ~cpu_to_le32p(crcp);
 137         return 0;
 138 }
 139
 140 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
 141                                unsigned int len, u8 *out)
 142 {
 143         return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 144                                     out);
 145 }
 146
 147 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
 148 {
 149         u32 *key = crypto_tfm_ctx(tfm);
 150
 151         *key = ~0;
 152
 153         return 0;
 154 }
 155
 156 static struct shash_alg alg = {
 157         .setkey                 =       crc32c_intel_setkey,
 158         .init                   =       crc32c_intel_init,
 159         .update                 =       crc32c_intel_update,
 160         .final                  =       crc32c_intel_final,
 161         .finup                  =       crc32c_intel_finup,
 162         .digest                 =       crc32c_intel_digest,
 163         .descsize               =       sizeof(u32),
 164         .digestsize             =       CHKSUM_DIGEST_SIZE,
 165         .base                   =       {
 166                 .cra_name               =       "crc32c",
 167                 .cra_driver_name        =       "crc32c-intel",
 168                 .cra_priority           =       200,
 169                 .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
 170                 .cra_ctxsize            =       sizeof(u32),
 171                 .cra_module             =       THIS_MODULE,
 172                 .cra_init               =       crc32c_intel_cra_init,
 173         }
 174 };
 175
 176
 177 static int __init crc32c_intel_mod_init(void)
 178 {
 179         if (cpu_has_xmm4_2)
 180                 return crypto_register_shash(&alg);
 181         else
 182                 return -ENODEV;
 183 }
 184
 185 static void __exit crc32c_intel_mod_fini(void)
 186 {
 187         crypto_unregister_shash(&alg);
 188 }
 189
 190 module_init(crc32c_intel_mod_init);
 191 module_exit(crc32c_intel_mod_fini);
 192
 193 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
 194 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 195 MODULE_LICENSE("GPL");
 196
 197 MODULE_ALIAS("crc32c");
 198 MODULE_ALIAS("crc32c-intel");