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 #include <asm/cpu_device_id.h>
  35
  36 #define CHKSUM_BLOCK_SIZE       1
  37 #define CHKSUM_DIGEST_SIZE      4
  38
  39 #define SCALE_F sizeof(unsigned long)
  40
  41 #ifdef CONFIG_X86_64
  42 #define REX_PRE "0x48, "
  43 #else
  44 #define REX_PRE
  45 #endif
  46
  47 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
  48 {
  49         while (length--) {
  50                 __asm__ __volatile__(
  51                         ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
  52                         :"=S"(crc)
  53                         :"0"(crc), "c"(*data)
  54                 );
  55                 data++;
  56         }
  57
  58         return crc;
  59 }
  60
  61 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
  62 {
  63         unsigned int iquotient = len / SCALE_F;
  64         unsigned int iremainder = len % SCALE_F;
  65         unsigned long *ptmp = (unsigned long *)p;
  66
  67         while (iquotient--) {
  68                 __asm__ __volatile__(
  69                         ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
  70                         :"=S"(crc)
  71                         :"0"(crc), "c"(*ptmp)
  72                 );
  73                 ptmp++;
  74         }
  75
  76         if (iremainder)
  77                 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
  78                                  iremainder);
  79
  80         return crc;
  81 }
  82
  83 /*
  84  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  85  * If your algorithm starts with ~0, then XOR with ~0 before you set
  86  * the seed.
  87  */
  88 static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
  89                         unsigned int keylen)
  90 {
  91         u32 *mctx = crypto_shash_ctx(hash);
  92
  93         if (keylen != sizeof(u32)) {
  94                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  95                 return -EINVAL;
  96         }
  97         *mctx = le32_to_cpup((__le32 *)key);
  98         return 0;
  99 }
 100
 101 static int crc32c_intel_init(struct shash_desc *desc)
 102 {
 103         u32 *mctx = crypto_shash_ctx(desc->tfm);
 104         u32 *crcp = shash_desc_ctx(desc);
 105
 106         *crcp = *mctx;
 107
 108         return 0;
 109 }
 110
 111 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
 112                                unsigned int len)
 113 {
 114         u32 *crcp = shash_desc_ctx(desc);
 115
 116         *crcp = crc32c_intel_le_hw(*crcp, data, len);
 117         return 0;
 118 }
 119
 120 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 121                                 u8 *out)
 122 {
 123         *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 124         return 0;
 125 }
 126
 127 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
 128                               unsigned int len, u8 *out)
 129 {
 130         return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
 131 }
 132
 133 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
 134 {
 135         u32 *crcp = shash_desc_ctx(desc);
 136
 137         *(__le32 *)out = ~cpu_to_le32p(crcp);
 138         return 0;
 139 }
 140
 141 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
 142                                unsigned int len, u8 *out)
 143 {
 144         return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 145                                     out);
 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         return 0;
 155 }
 156
 157 static struct shash_alg alg = {
 158         .setkey                 =       crc32c_intel_setkey,
 159         .init                   =       crc32c_intel_init,
 160         .update                 =       crc32c_intel_update,
 161         .final                  =       crc32c_intel_final,
 162         .finup                  =       crc32c_intel_finup,
 163         .digest                 =       crc32c_intel_digest,
 164         .descsize               =       sizeof(u32),
 165         .digestsize             =       CHKSUM_DIGEST_SIZE,
 166         .base                   =       {
 167                 .cra_name               =       "crc32c",
 168                 .cra_driver_name        =       "crc32c-intel",
 169                 .cra_priority           =       200,
 170                 .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
 171                 .cra_ctxsize            =       sizeof(u32),
 172                 .cra_module             =       THIS_MODULE,
 173                 .cra_init               =       crc32c_intel_cra_init,
 174         }
 175 };
 176
 177 static const struct x86_cpu_id crc32c_cpu_id[] = {
 178         X86_FEATURE_MATCH(X86_FEATURE_XMM4_2),
 179         {}
 180 };
 181 MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
 182
 183 static int __init crc32c_intel_mod_init(void)
 184 {
 185         if (!x86_match_cpu(crc32c_cpu_id))
 186                 return -ENODEV;
 187         return crypto_register_shash(&alg);
 188 }
 189
 190 static void __exit crc32c_intel_mod_fini(void)
 191 {
 192         crypto_unregister_shash(&alg);
 193 }
 194
 195 module_init(crc32c_intel_mod_init);
 196 module_exit(crc32c_intel_mod_fini);
 197
 198 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
 199 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 200 MODULE_LICENSE("GPL");
 201
 202 MODULE_ALIAS("crc32c");
 203 MODULE_ALIAS("crc32c-intel");