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25 * Copyright 2012 Xyratex Technology Limited
27 * Wrappers for kernel crypto shash api to pclmulqdq crc32 imlementation.
29 #include <linux/init.h>
30 #include <linux/module.h>
31 #include <linux/string.h>
32 #include <linux/kernel.h>
33 #include <linux/crc32.h>
34 #include <crypto/internal/hash.h>
35 #include <crypto/internal/simd.h>
37 #include <asm/cpufeatures.h>
38 #include <asm/cpu_device_id.h>
41 #define CHKSUM_BLOCK_SIZE 1
42 #define CHKSUM_DIGEST_SIZE 4
44 #define PCLMUL_MIN_LEN 64L /* minimum size of buffer
45 * for crc32_pclmul_le_16 */
46 #define SCALE_F 16L /* size of xmm register */
47 #define SCALE_F_MASK (SCALE_F - 1)
49 u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32);
51 static u32 __attribute__((pure))
52 crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len)
54 unsigned int iquotient;
55 unsigned int iremainder;
56 unsigned int prealign;
58 if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !crypto_simd_usable())
59 return crc32_le(crc, p, len);
61 if ((long)p & SCALE_F_MASK) {
62 /* align p to 16 byte */
63 prealign = SCALE_F - ((long)p & SCALE_F_MASK);
65 crc = crc32_le(crc, p, prealign);
67 p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) &
70 iquotient = len & (~SCALE_F_MASK);
71 iremainder = len & SCALE_F_MASK;
74 crc = crc32_pclmul_le_16(p, iquotient, crc);
78 crc = crc32_le(crc, p + iquotient, iremainder);
83 static int crc32_pclmul_cra_init(struct crypto_tfm *tfm)
85 u32 *key = crypto_tfm_ctx(tfm);
92 static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
95 u32 *mctx = crypto_shash_ctx(hash);
97 if (keylen != sizeof(u32)) {
98 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
101 *mctx = le32_to_cpup((__le32 *)key);
105 static int crc32_pclmul_init(struct shash_desc *desc)
107 u32 *mctx = crypto_shash_ctx(desc->tfm);
108 u32 *crcp = shash_desc_ctx(desc);
115 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data,
118 u32 *crcp = shash_desc_ctx(desc);
120 *crcp = crc32_pclmul_le(*crcp, data, len);
124 /* No final XOR 0xFFFFFFFF, like crc32_le */
125 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
128 *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len));
132 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data,
133 unsigned int len, u8 *out)
135 return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out);
138 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out)
140 u32 *crcp = shash_desc_ctx(desc);
142 *(__le32 *)out = cpu_to_le32p(crcp);
146 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data,
147 unsigned int len, u8 *out)
149 return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
153 static struct shash_alg alg = {
154 .setkey = crc32_pclmul_setkey,
155 .init = crc32_pclmul_init,
156 .update = crc32_pclmul_update,
157 .final = crc32_pclmul_final,
158 .finup = crc32_pclmul_finup,
159 .digest = crc32_pclmul_digest,
160 .descsize = sizeof(u32),
161 .digestsize = CHKSUM_DIGEST_SIZE,
164 .cra_driver_name = "crc32-pclmul",
166 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
167 .cra_blocksize = CHKSUM_BLOCK_SIZE,
168 .cra_ctxsize = sizeof(u32),
169 .cra_module = THIS_MODULE,
170 .cra_init = crc32_pclmul_cra_init,
174 static const struct x86_cpu_id crc32pclmul_cpu_id[] = {
175 X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ),
178 MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id);
181 static int __init crc32_pclmul_mod_init(void)
184 if (!x86_match_cpu(crc32pclmul_cpu_id)) {
185 pr_info("PCLMULQDQ-NI instructions are not detected.\n");
188 return crypto_register_shash(&alg);
191 static void __exit crc32_pclmul_mod_fini(void)
193 crypto_unregister_shash(&alg);
196 module_init(crc32_pclmul_mod_init);
197 module_exit(crc32_pclmul_mod_fini);
199 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
200 MODULE_LICENSE("GPL");
202 MODULE_ALIAS_CRYPTO("crc32");
203 MODULE_ALIAS_CRYPTO("crc32-pclmul");