libcfs/libcfs/linux/linux-crypto-crc32c-pclmul.c

   1 /* GPL HEADER START
   2  *
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License version 2 for more details (a copy is included
  13  * in the LICENSE file that accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * version 2 along with this program; If not, see http://www.gnu.org/licenses
  17  *
  18  * Please  visit http://www.xyratex.com/contact if you need additional
  19  * information or have any questions.
  20  *
  21  * GPL HEADER END
  22  */
  23
  24 /*
  25  * Wrappers for kernel crypto shash api to pclmulqdq crc32c imlementation.
  26  *
  27  * Author:     James Simmons <jsimmons@infradead.org>
  28  */
  29 #include <linux/crc32.h>
  30 #include <crypto/internal/hash.h>
  31 #include <linux/crc32.h>
  32 #include <asm/cpufeature.h>
  33 #ifdef HAVE_FPU_API_HEADER
  34 #include <asm/fpu/api.h>
  35 #else
  36 #include <asm/i387.h>
  37 #endif
  38 #include <libcfs/libcfs.h>
  39
  40 #define CHKSUM_BLOCK_SIZE       1
  41 #define CHKSUM_DIGEST_SIZE      4
  42
  43 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
  44                                 unsigned int crc_init);
  45
  46 static int crc32c_pclmul_cra_init(struct crypto_tfm *tfm)
  47 {
  48         u32 *key = crypto_tfm_ctx(tfm);
  49
  50         *key = ~0;
  51         return 0;
  52 }
  53
  54 /*
  55  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  56  * If your algorithm starts with ~0, then XOR with ~0 before you set
  57  * the seed.
  58  */
  59 static int crc32c_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
  60                         unsigned int keylen)
  61 {
  62         u32 *mctx = crypto_shash_ctx(hash);
  63
  64         if (keylen != sizeof(u32)) {
  65                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  66                 return -EINVAL;
  67         }
  68         *mctx = le32_to_cpup((__le32 *)key);
  69         return 0;
  70 }
  71
  72 static int crc32c_pclmul_init(struct shash_desc *desc)
  73 {
  74         u32 *mctx = crypto_shash_ctx(desc->tfm);
  75         u32 *crcp = shash_desc_ctx(desc);
  76
  77         *crcp = *mctx;
  78         return 0;
  79 }
  80
  81 static int crc32c_pclmul_update(struct shash_desc *desc, const u8 *data,
  82                                unsigned int len)
  83 {
  84         u32 *crcp = shash_desc_ctx(desc);
  85
  86         kernel_fpu_begin();
  87         *crcp = crc_pcl(data, len, *crcp);
  88         kernel_fpu_end();
  89         return 0;
  90 }
  91
  92 /* No final XOR 0xFFFFFFFF, like crc32_le */
  93 static int __crc32c_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
  94                                 u8 *out)
  95 {
  96         kernel_fpu_begin();
  97         *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
  98         kernel_fpu_end();
  99         return 0;
 100 }
 101
 102 static int crc32c_pclmul_finup(struct shash_desc *desc, const u8 *data,
 103                               unsigned int len, u8 *out)
 104 {
 105         return __crc32c_pclmul_finup(shash_desc_ctx(desc), data, len, out);
 106 }
 107
 108 static int crc32c_pclmul_digest(struct shash_desc *desc, const u8 *data,
 109                                unsigned int len, u8 *out)
 110 {
 111         return __crc32c_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
 112                                     out);
 113 }
 114
 115 static int crc32c_pclmul_final(struct shash_desc *desc, u8 *out)
 116 {
 117         u32 *crcp = shash_desc_ctx(desc);
 118
 119         *(__le32 *)out = ~cpu_to_le32p(crcp);
 120         return 0;
 121 }
 122
 123 static struct shash_alg alg = {
 124         .setkey         = crc32c_pclmul_setkey,
 125         .init           = crc32c_pclmul_init,
 126         .update         = crc32c_pclmul_update,
 127         .final          = crc32c_pclmul_final,
 128         .finup          = crc32c_pclmul_finup,
 129         .digest         = crc32c_pclmul_digest,
 130         .descsize       = sizeof(u32),
 131         .digestsize     = CHKSUM_DIGEST_SIZE,
 132         .base           = {
 133                         .cra_name               = "crc32c",
 134                         .cra_driver_name        = "crc32c-pclmul",
 135                         .cra_priority           = 150,
 136                         .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 137                         .cra_ctxsize            = sizeof(u32),
 138                         .cra_module             = THIS_MODULE,
 139                         .cra_init               = crc32c_pclmul_cra_init,
 140         }
 141 };
 142
 143 #ifndef X86_FEATURE_XMM4_2
 144 #define X86_FEATURE_XMM4_2      (4*32+20)       /* "sse4_2" SSE-4.2 */
 145 #endif
 146
 147 int cfs_crypto_crc32c_pclmul_register(void)
 148 {
 149         if (!boot_cpu_has(X86_FEATURE_XMM4_2)) {
 150                 CDEBUG(D_INFO, "CRC32 instruction is not detected.\n");
 151                 return -ENODEV;
 152         }
 153         return crypto_register_shash(&alg);
 154 }
 155
 156 void cfs_crypto_crc32c_pclmul_unregister(void)
 157 {
 158         crypto_unregister_shash(&alg);
 159 }