arch/powerpc/crypto/crc32c-vpmsum_glue.c

   1 #include <linux/crc32.h>
   2 #include <crypto/internal/hash.h>
   3 #include <crypto/internal/simd.h>
   4 #include <linux/init.h>
   5 #include <linux/module.h>
   6 #include <linux/string.h>
   7 #include <linux/kernel.h>
   8 #include <linux/cpufeature.h>
   9 #include <asm/simd.h>
  10 #include <asm/switch_to.h>
  11
  12 #define CHKSUM_BLOCK_SIZE       1
  13 #define CHKSUM_DIGEST_SIZE      4
  14
  15 #define VMX_ALIGN               16
  16 #define VMX_ALIGN_MASK          (VMX_ALIGN-1)
  17
  18 #define VECTOR_BREAKPOINT       512
  19
  20 u32 __crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len);
  21
  22 static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len)
  23 {
  24         unsigned int prealign;
  25         unsigned int tail;
  26
  27         if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
  28                 return __crc32c_le(crc, p, len);
  29
  30         if ((unsigned long)p & VMX_ALIGN_MASK) {
  31                 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
  32                 crc = __crc32c_le(crc, p, prealign);
  33                 len -= prealign;
  34                 p += prealign;
  35         }
  36
  37         if (len & ~VMX_ALIGN_MASK) {
  38                 preempt_disable();
  39                 pagefault_disable();
  40                 enable_kernel_altivec();
  41                 crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
  42                 disable_kernel_altivec();
  43                 pagefault_enable();
  44                 preempt_enable();
  45         }
  46
  47         tail = len & VMX_ALIGN_MASK;
  48         if (tail) {
  49                 p += len & ~VMX_ALIGN_MASK;
  50                 crc = __crc32c_le(crc, p, tail);
  51         }
  52
  53         return crc;
  54 }
  55
  56 static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
  57 {
  58         u32 *key = crypto_tfm_ctx(tfm);
  59
  60         *key = ~0;
  61
  62         return 0;
  63 }
  64
  65 /*
  66  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  67  * If your algorithm starts with ~0, then XOR with ~0 before you set
  68  * the seed.
  69  */
  70 static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
  71                                unsigned int keylen)
  72 {
  73         u32 *mctx = crypto_shash_ctx(hash);
  74
  75         if (keylen != sizeof(u32)) {
  76                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  77                 return -EINVAL;
  78         }
  79         *mctx = le32_to_cpup((__le32 *)key);
  80         return 0;
  81 }
  82
  83 static int crc32c_vpmsum_init(struct shash_desc *desc)
  84 {
  85         u32 *mctx = crypto_shash_ctx(desc->tfm);
  86         u32 *crcp = shash_desc_ctx(desc);
  87
  88         *crcp = *mctx;
  89
  90         return 0;
  91 }
  92
  93 static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
  94                                unsigned int len)
  95 {
  96         u32 *crcp = shash_desc_ctx(desc);
  97
  98         *crcp = crc32c_vpmsum(*crcp, data, len);
  99
 100         return 0;
 101 }
 102
 103 static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
 104                                 u8 *out)
 105 {
 106         *(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
 107
 108         return 0;
 109 }
 110
 111 static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
 112                               unsigned int len, u8 *out)
 113 {
 114         return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
 115 }
 116
 117 static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
 118 {
 119         u32 *crcp = shash_desc_ctx(desc);
 120
 121         *(__le32 *)out = ~cpu_to_le32p(crcp);
 122
 123         return 0;
 124 }
 125
 126 static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
 127                                unsigned int len, u8 *out)
 128 {
 129         return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
 130                                      out);
 131 }
 132
 133 static struct shash_alg alg = {
 134         .setkey         = crc32c_vpmsum_setkey,
 135         .init           = crc32c_vpmsum_init,
 136         .update         = crc32c_vpmsum_update,
 137         .final          = crc32c_vpmsum_final,
 138         .finup          = crc32c_vpmsum_finup,
 139         .digest         = crc32c_vpmsum_digest,
 140         .descsize       = sizeof(u32),
 141         .digestsize     = CHKSUM_DIGEST_SIZE,
 142         .base           = {
 143                 .cra_name               = "crc32c",
 144                 .cra_driver_name        = "crc32c-vpmsum",
 145                 .cra_priority           = 200,
 146                 .cra_flags              = CRYPTO_ALG_OPTIONAL_KEY,
 147                 .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 148                 .cra_ctxsize            = sizeof(u32),
 149                 .cra_module             = THIS_MODULE,
 150                 .cra_init               = crc32c_vpmsum_cra_init,
 151         }
 152 };
 153
 154 static int __init crc32c_vpmsum_mod_init(void)
 155 {
 156         if (!cpu_has_feature(CPU_FTR_ARCH_207S))
 157                 return -ENODEV;
 158
 159         return crypto_register_shash(&alg);
 160 }
 161
 162 static void __exit crc32c_vpmsum_mod_fini(void)
 163 {
 164         crypto_unregister_shash(&alg);
 165 }
 166
 167 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
 168 module_exit(crc32c_vpmsum_mod_fini);
 169
 170 MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
 171 MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
 172 MODULE_LICENSE("GPL");
 173 MODULE_ALIAS_CRYPTO("crc32c");
 174 MODULE_ALIAS_CRYPTO("crc32c-vpmsum");