LXR linux/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
  46static 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
  60static 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 */
  87static 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
 100static 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
 110static 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
 119static 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
 126static 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
 132static 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
 140static 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
 147static 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
 156static 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
 177static 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
 185static void __exit crc32c_intel_mod_fini(void)
 186{
 187        crypto_unregister_shash(&alg);
 188}
 189
 190module_init(crc32c_intel_mod_init);
 191module_exit(crc32c_intel_mod_fini);
 192
 193MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
 194MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 195MODULE_LICENSE("GPL");
 196
 197MODULE_ALIAS("crc32c");
 198MODULE_ALIAS("crc32c-intel");
 199