arch/x86/crypto/crc32c-intel_glue.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/cpufeatures.h>
  34 #include <asm/cpu_device_id.h>
  35 #include <asm/fpu/internal.h>
  36
  37 #define CHKSUM_BLOCK_SIZE       1
  38 #define CHKSUM_DIGEST_SIZE      4
  39
  40 #define SCALE_F sizeof(unsigned long)
  41
  42 #ifdef CONFIG_X86_64
  43 #define REX_PRE "0x48, "
  44 #else
  45 #define REX_PRE
  46 #endif
  47
  48 #ifdef CONFIG_X86_64
  49 /*
  50  * use carryless multiply version of crc32c when buffer
  51  * size is >= 512 to account
  52  * for fpu state save/restore overhead.
  53  */
  54 #define CRC32C_PCL_BREAKEVEN    512
  55
  56 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
  57                                 unsigned int crc_init);
  58 #endif /* CONFIG_X86_64 */
  59
  60 static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
  61 {
  62         while (length--) {
  63                 __asm__ __volatile__(
  64                         ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
  65                         :"=S"(crc)
  66                         :"0"(crc), "c"(*data)
  67                 );
  68                 data++;
  69         }
  70
  71         return crc;
  72 }
  73
  74 static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
  75 {
  76         unsigned int iquotient = len / SCALE_F;
  77         unsigned int iremainder = len % SCALE_F;
  78         unsigned long *ptmp = (unsigned long *)p;
  79
  80         while (iquotient--) {
  81                 __asm__ __volatile__(
  82                         ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
  83                         :"=S"(crc)
  84                         :"0"(crc), "c"(*ptmp)
  85                 );
  86                 ptmp++;
  87         }
  88
  89         if (iremainder)
  90                 crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
  91                                  iremainder);
  92
  93         return crc;
  94 }
  95
  96 /*
  97  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  98  * If your algorithm starts with ~0, then XOR with ~0 before you set
  99  * the seed.
 100  */
 101 static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
 102                         unsigned int keylen)
 103 {
 104         u32 *mctx = crypto_shash_ctx(hash);
 105
 106         if (keylen != sizeof(u32)) {
 107                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
 108                 return -EINVAL;
 109         }
 110         *mctx = le32_to_cpup((__le32 *)key);
 111         return 0;
 112 }
 113
 114 static int crc32c_intel_init(struct shash_desc *desc)
 115 {
 116         u32 *mctx = crypto_shash_ctx(desc->tfm);
 117         u32 *crcp = shash_desc_ctx(desc);
 118
 119         *crcp = *mctx;
 120
 121         return 0;
 122 }
 123
 124 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
 125                                unsigned int len)
 126 {
 127         u32 *crcp = shash_desc_ctx(desc);
 128
 129         *crcp = crc32c_intel_le_hw(*crcp, data, len);
 130         return 0;
 131 }
 132
 133 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 134                                 u8 *out)
 135 {
 136         *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 137         return 0;
 138 }
 139
 140 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
 141                               unsigned int len, u8 *out)
 142 {
 143         return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
 144 }
 145
 146 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
 147 {
 148         u32 *crcp = shash_desc_ctx(desc);
 149
 150         *(__le32 *)out = ~cpu_to_le32p(crcp);
 151         return 0;
 152 }
 153
 154 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
 155                                unsigned int len, u8 *out)
 156 {
 157         return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 158                                     out);
 159 }
 160
 161 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
 162 {
 163         u32 *key = crypto_tfm_ctx(tfm);
 164
 165         *key = ~0;
 166
 167         return 0;
 168 }
 169
 170 #ifdef CONFIG_X86_64
 171 static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
 172                                unsigned int len)
 173 {
 174         u32 *crcp = shash_desc_ctx(desc);
 175
 176         /*
 177          * use faster PCL version if datasize is large enough to
 178          * overcome kernel fpu state save/restore overhead
 179          */
 180         if (len >= CRC32C_PCL_BREAKEVEN && irq_fpu_usable()) {
 181                 kernel_fpu_begin();
 182                 *crcp = crc_pcl(data, len, *crcp);
 183                 kernel_fpu_end();
 184         } else
 185                 *crcp = crc32c_intel_le_hw(*crcp, data, len);
 186         return 0;
 187 }
 188
 189 static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
 190                                 u8 *out)
 191 {
 192         if (len >= CRC32C_PCL_BREAKEVEN && irq_fpu_usable()) {
 193                 kernel_fpu_begin();
 194                 *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
 195                 kernel_fpu_end();
 196         } else
 197                 *(__le32 *)out =
 198                         ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
 199         return 0;
 200 }
 201
 202 static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
 203                               unsigned int len, u8 *out)
 204 {
 205         return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
 206 }
 207
 208 static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
 209                                unsigned int len, u8 *out)
 210 {
 211         return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
 212                                     out);
 213 }
 214 #endif /* CONFIG_X86_64 */
 215
 216 static struct shash_alg alg = {
 217         .setkey                 =       crc32c_intel_setkey,
 218         .init                   =       crc32c_intel_init,
 219         .update                 =       crc32c_intel_update,
 220         .final                  =       crc32c_intel_final,
 221         .finup                  =       crc32c_intel_finup,
 222         .digest                 =       crc32c_intel_digest,
 223         .descsize               =       sizeof(u32),
 224         .digestsize             =       CHKSUM_DIGEST_SIZE,
 225         .base                   =       {
 226                 .cra_name               =       "crc32c",
 227                 .cra_driver_name        =       "crc32c-intel",
 228                 .cra_priority           =       200,
 229                 .cra_flags              =       CRYPTO_ALG_OPTIONAL_KEY,
 230                 .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
 231                 .cra_ctxsize            =       sizeof(u32),
 232                 .cra_module             =       THIS_MODULE,
 233                 .cra_init               =       crc32c_intel_cra_init,
 234         }
 235 };
 236
 237 static const struct x86_cpu_id crc32c_cpu_id[] = {
 238         X86_FEATURE_MATCH(X86_FEATURE_XMM4_2),
 239         {}
 240 };
 241 MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);
 242
 243 static int __init crc32c_intel_mod_init(void)
 244 {
 245         if (!x86_match_cpu(crc32c_cpu_id))
 246                 return -ENODEV;
 247 #ifdef CONFIG_X86_64
 248         if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {
 249                 alg.update = crc32c_pcl_intel_update;
 250                 alg.finup = crc32c_pcl_intel_finup;
 251                 alg.digest = crc32c_pcl_intel_digest;
 252         }
 253 #endif
 254         return crypto_register_shash(&alg);
 255 }
 256
 257 static void __exit crc32c_intel_mod_fini(void)
 258 {
 259         crypto_unregister_shash(&alg);
 260 }
 261
 262 module_init(crc32c_intel_mod_init);
 263 module_exit(crc32c_intel_mod_fini);
 264
 265 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
 266 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
 267 MODULE_LICENSE("GPL");
 268
 269 MODULE_ALIAS_CRYPTO("crc32c");
 270 MODULE_ALIAS_CRYPTO("crc32c-intel");