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