arch/powerpc/crypto/crc32c-vpmsum_glue.c

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