arch/powerpc/crypto/crc32c-vpmsum_glue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/crc32.h>
   3 #include <crypto/internal/hash.h>
   4 #include <crypto/internal/simd.h>
   5 #include <linux/init.h>
   6 #include <linux/module.h>
   7 #include <linux/string.h>
   8 #include <linux/kernel.h>
   9 #include <linux/cpufeature.h>
  10 #include <asm/simd.h>
  11 #include <asm/switch_to.h>
  12
  13 #define CHKSUM_BLOCK_SIZE       1
  14 #define CHKSUM_DIGEST_SIZE      4
  15
  16 #define VMX_ALIGN               16
  17 #define VMX_ALIGN_MASK          (VMX_ALIGN-1)
  18
  19 #define VECTOR_BREAKPOINT       512
  20
  21 u32 __crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len);
  22
  23 static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len)
  24 {
  25         unsigned int prealign;
  26         unsigned int tail;
  27
  28         if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
  29                 return __crc32c_le(crc, p, len);
  30
  31         if ((unsigned long)p & VMX_ALIGN_MASK) {
  32                 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
  33                 crc = __crc32c_le(crc, p, prealign);
  34                 len -= prealign;
  35                 p += prealign;
  36         }
  37
  38         if (len & ~VMX_ALIGN_MASK) {
  39                 preempt_disable();
  40                 pagefault_disable();
  41                 enable_kernel_altivec();
  42                 crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
  43                 disable_kernel_altivec();
  44                 pagefault_enable();
  45                 preempt_enable();
  46         }
  47
  48         tail = len & VMX_ALIGN_MASK;
  49         if (tail) {
  50                 p += len & ~VMX_ALIGN_MASK;
  51                 crc = __crc32c_le(crc, p, tail);
  52         }
  53
  54         return crc;
  55 }
  56
  57 static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
  58 {
  59         u32 *key = crypto_tfm_ctx(tfm);
  60
  61         *key = ~0;
  62
  63         return 0;
  64 }
  65
  66 /*
  67  * Setting the seed allows arbitrary accumulators and flexible XOR policy
  68  * If your algorithm starts with ~0, then XOR with ~0 before you set
  69  * the seed.
  70  */
  71 static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
  72                                unsigned int keylen)
  73 {
  74         u32 *mctx = crypto_shash_ctx(hash);
  75
  76         if (keylen != sizeof(u32)) {
  77                 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
  78                 return -EINVAL;
  79         }
  80         *mctx = le32_to_cpup((__le32 *)key);
  81         return 0;
  82 }
  83
  84 static int crc32c_vpmsum_init(struct shash_desc *desc)
  85 {
  86         u32 *mctx = crypto_shash_ctx(desc->tfm);
  87         u32 *crcp = shash_desc_ctx(desc);
  88
  89         *crcp = *mctx;
  90
  91         return 0;
  92 }
  93
  94 static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
  95                                unsigned int len)
  96 {
  97         u32 *crcp = shash_desc_ctx(desc);
  98
  99         *crcp = crc32c_vpmsum(*crcp, data, len);
 100
 101         return 0;
 102 }
 103
 104 static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
 105                                 u8 *out)
 106 {
 107         *(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
 108
 109         return 0;
 110 }
 111
 112 static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
 113                               unsigned int len, u8 *out)
 114 {
 115         return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
 116 }
 117
 118 static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
 119 {
 120         u32 *crcp = shash_desc_ctx(desc);
 121
 122         *(__le32 *)out = ~cpu_to_le32p(crcp);
 123
 124         return 0;
 125 }
 126
 127 static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
 128                                unsigned int len, u8 *out)
 129 {
 130         return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
 131                                      out);
 132 }
 133
 134 static struct shash_alg alg = {
 135         .setkey         = crc32c_vpmsum_setkey,
 136         .init           = crc32c_vpmsum_init,
 137         .update         = crc32c_vpmsum_update,
 138         .final          = crc32c_vpmsum_final,
 139         .finup          = crc32c_vpmsum_finup,
 140         .digest         = crc32c_vpmsum_digest,
 141         .descsize       = sizeof(u32),
 142         .digestsize     = CHKSUM_DIGEST_SIZE,
 143         .base           = {
 144                 .cra_name               = "crc32c",
 145                 .cra_driver_name        = "crc32c-vpmsum",
 146                 .cra_priority           = 200,
 147                 .cra_flags              = CRYPTO_ALG_OPTIONAL_KEY,
 148                 .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 149                 .cra_ctxsize            = sizeof(u32),
 150                 .cra_module             = THIS_MODULE,
 151                 .cra_init               = crc32c_vpmsum_cra_init,
 152         }
 153 };
 154
 155 static int __init crc32c_vpmsum_mod_init(void)
 156 {
 157         if (!cpu_has_feature(CPU_FTR_ARCH_207S))
 158                 return -ENODEV;
 159
 160         return crypto_register_shash(&alg);
 161 }
 162
 163 static void __exit crc32c_vpmsum_mod_fini(void)
 164 {
 165         crypto_unregister_shash(&alg);
 166 }
 167
 168 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
 169 module_exit(crc32c_vpmsum_mod_fini);
 170
 171 MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
 172 MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
 173 MODULE_LICENSE("GPL");
 174 MODULE_ALIAS_CRYPTO("crc32c");
 175 MODULE_ALIAS_CRYPTO("crc32c-vpmsum");