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

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  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 #include <asm/i387.h>
  34 #include <libcfs/libcfs.h>
  35
  36 #define CHKSUM_BLOCK_SIZE       1
  37 #define CHKSUM_DIGEST_SIZE      4
  38
  39 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
  40                                 unsigned int crc_init);
  41
  42 static int crc32c_pclmul_cra_init(struct crypto_tfm *tfm)
  43 {
  44         u32 *key = crypto_tfm_ctx(tfm);
  45
  46         *key = ~0;
  47         return 0;
  48 }
  49
  50 /*
  51  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  52  * If your algorithm starts with ~0, then XOR with ~0 before you set
  53  * the seed.
  54  */
  55 static int crc32c_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
  56                         unsigned int keylen)
  57 {
  58         u32 *mctx = crypto_shash_ctx(hash);
  59
  60         if (keylen != sizeof(u32)) {
  61                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  62                 return -EINVAL;
  63         }
  64         *mctx = le32_to_cpup((__le32 *)key);
  65         return 0;
  66 }
  67
  68 static int crc32c_pclmul_init(struct shash_desc *desc)
  69 {
  70         u32 *mctx = crypto_shash_ctx(desc->tfm);
  71         u32 *crcp = shash_desc_ctx(desc);
  72
  73         *crcp = *mctx;
  74         return 0;
  75 }
  76
  77 static int crc32c_pclmul_update(struct shash_desc *desc, const u8 *data,
  78                                unsigned int len)
  79 {
  80         u32 *crcp = shash_desc_ctx(desc);
  81
  82         kernel_fpu_begin();
  83         *crcp = crc_pcl(data, len, *crcp);
  84         kernel_fpu_end();
  85         return 0;
  86 }
  87
  88 /* No final XOR 0xFFFFFFFF, like crc32_le */
  89 static int __crc32c_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
  90                                 u8 *out)
  91 {
  92         kernel_fpu_begin();
  93         *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
  94         kernel_fpu_end();
  95         return 0;
  96 }
  97
  98 static int crc32c_pclmul_finup(struct shash_desc *desc, const u8 *data,
  99                               unsigned int len, u8 *out)
 100 {
 101         return __crc32c_pclmul_finup(shash_desc_ctx(desc), data, len, out);
 102 }
 103
 104 static int crc32c_pclmul_digest(struct shash_desc *desc, const u8 *data,
 105                                unsigned int len, u8 *out)
 106 {
 107         return __crc32c_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
 108                                     out);
 109 }
 110
 111 static int crc32c_pclmul_final(struct shash_desc *desc, u8 *out)
 112 {
 113         u32 *crcp = shash_desc_ctx(desc);
 114
 115         *(__le32 *)out = ~cpu_to_le32p(crcp);
 116         return 0;
 117 }
 118
 119 static struct shash_alg alg = {
 120         .setkey         = crc32c_pclmul_setkey,
 121         .init           = crc32c_pclmul_init,
 122         .update         = crc32c_pclmul_update,
 123         .final          = crc32c_pclmul_final,
 124         .finup          = crc32c_pclmul_finup,
 125         .digest         = crc32c_pclmul_digest,
 126         .descsize       = sizeof(u32),
 127         .digestsize     = CHKSUM_DIGEST_SIZE,
 128         .base           = {
 129                         .cra_name               = "crc32c",
 130                         .cra_driver_name        = "crc32c-pclmul",
 131                         .cra_priority           = 150,
 132                         .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 133                         .cra_ctxsize            = sizeof(u32),
 134                         .cra_module             = THIS_MODULE,
 135                         .cra_init               = crc32c_pclmul_cra_init,
 136         }
 137 };
 138
 139 #ifndef X86_FEATURE_XMM4_2
 140 #define X86_FEATURE_XMM4_2      (4*32+20)       /* "sse4_2" SSE-4.2 */
 141 #endif
 142
 143 int cfs_crypto_crc32c_pclmul_register(void)
 144 {
 145         if (!boot_cpu_has(X86_FEATURE_XMM4_2)) {
 146                 CDEBUG(D_INFO, "CRC32 instruction is not detected.\n");
 147                 return -ENODEV;
 148         }
 149         return crypto_register_shash(&alg);
 150 }
 151
 152 void cfs_crypto_crc32c_pclmul_unregister(void)
 153 {
 154         crypto_unregister_shash(&alg);
 155 }