1 /* GPL HEADER START
2 *
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 only,
7 * as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License version 2 for more details (a copy is included
13 * in the LICENSE file that accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License
16 * version 2 along with this program; If not, see http://www.gnu.org/licenses
17 *
18 * Please visit http://www.xyratex.com/contact if you need additional
19 * information or have any questions.
20 *
21 * GPL HEADER END
22 */
23
24 /*
25 * Copyright 2012 Xyratex Technology Limited
26 *
27 * Wrappers for kernel crypto shash api to pclmulqdq crc32 imlementation.
28 */
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
36 #include <asm/cpufeature.h>
37 #include <asm/cpu_device_id.h>
38 #include <asm/i387.h>
39
40 #define CHKSUM_BLOCK_SIZE 1
41 #define CHKSUM_DIGEST_SIZE 4
42
43 #define PCLMUL_MIN_LEN 64L /* minimum size of buffer
44 * for crc32_pclmul_le_16 */
45 #define SCALE_F 16L /* size of xmm register */
46 #define SCALE_F_MASK (SCALE_F - 1)
47
48 u32 crc32_pclmul_le_16(unsigned char const *buffer, size_t len, u32 crc32);
49
50 static u32 __attribute__((pure))
crc32_pclmul_le(u32 crc,unsigned char const * p,size_t len)51 crc32_pclmul_le(u32 crc, unsigned char const *p, size_t len)
52 {
53 unsigned int iquotient;
54 unsigned int iremainder;
55 unsigned int prealign;
56
57 if (len < PCLMUL_MIN_LEN + SCALE_F_MASK || !irq_fpu_usable())
58 return crc32_le(crc, p, len);
59
60 if ((long)p & SCALE_F_MASK) {
61 /* align p to 16 byte */
62 prealign = SCALE_F - ((long)p & SCALE_F_MASK);
63
64 crc = crc32_le(crc, p, prealign);
65 len -= prealign;
66 p = (unsigned char *)(((unsigned long)p + SCALE_F_MASK) &
67 ~SCALE_F_MASK);
68 }
69 iquotient = len & (~SCALE_F_MASK);
70 iremainder = len & SCALE_F_MASK;
71
72 kernel_fpu_begin();
73 crc = crc32_pclmul_le_16(p, iquotient, crc);
74 kernel_fpu_end();
75
76 if (iremainder)
77 crc = crc32_le(crc, p + iquotient, iremainder);
78
79 return crc;
80 }
81
crc32_pclmul_cra_init(struct crypto_tfm * tfm)82 static int crc32_pclmul_cra_init(struct crypto_tfm *tfm)
83 {
84 u32 *key = crypto_tfm_ctx(tfm);
85
86 *key = 0;
87
88 return 0;
89 }
90
crc32_pclmul_setkey(struct crypto_shash * hash,const u8 * key,unsigned int keylen)91 static int crc32_pclmul_setkey(struct crypto_shash *hash, const u8 *key,
92 unsigned int keylen)
93 {
94 u32 *mctx = crypto_shash_ctx(hash);
95
96 if (keylen != sizeof(u32)) {
97 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
98 return -EINVAL;
99 }
100 *mctx = le32_to_cpup((__le32 *)key);
101 return 0;
102 }
103
crc32_pclmul_init(struct shash_desc * desc)104 static int crc32_pclmul_init(struct shash_desc *desc)
105 {
106 u32 *mctx = crypto_shash_ctx(desc->tfm);
107 u32 *crcp = shash_desc_ctx(desc);
108
109 *crcp = *mctx;
110
111 return 0;
112 }
113
crc32_pclmul_update(struct shash_desc * desc,const u8 * data,unsigned int len)114 static int crc32_pclmul_update(struct shash_desc *desc, const u8 *data,
115 unsigned int len)
116 {
117 u32 *crcp = shash_desc_ctx(desc);
118
119 *crcp = crc32_pclmul_le(*crcp, data, len);
120 return 0;
121 }
122
123 /* No final XOR 0xFFFFFFFF, like crc32_le */
__crc32_pclmul_finup(u32 * crcp,const u8 * data,unsigned int len,u8 * out)124 static int __crc32_pclmul_finup(u32 *crcp, const u8 *data, unsigned int len,
125 u8 *out)
126 {
127 *(__le32 *)out = cpu_to_le32(crc32_pclmul_le(*crcp, data, len));
128 return 0;
129 }
130
crc32_pclmul_finup(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)131 static int crc32_pclmul_finup(struct shash_desc *desc, const u8 *data,
132 unsigned int len, u8 *out)
133 {
134 return __crc32_pclmul_finup(shash_desc_ctx(desc), data, len, out);
135 }
136
crc32_pclmul_final(struct shash_desc * desc,u8 * out)137 static int crc32_pclmul_final(struct shash_desc *desc, u8 *out)
138 {
139 u32 *crcp = shash_desc_ctx(desc);
140
141 *(__le32 *)out = cpu_to_le32p(crcp);
142 return 0;
143 }
144
crc32_pclmul_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)145 static int crc32_pclmul_digest(struct shash_desc *desc, const u8 *data,
146 unsigned int len, u8 *out)
147 {
148 return __crc32_pclmul_finup(crypto_shash_ctx(desc->tfm), data, len,
149 out);
150 }
151
152 static struct shash_alg alg = {
153 .setkey = crc32_pclmul_setkey,
154 .init = crc32_pclmul_init,
155 .update = crc32_pclmul_update,
156 .final = crc32_pclmul_final,
157 .finup = crc32_pclmul_finup,
158 .digest = crc32_pclmul_digest,
159 .descsize = sizeof(u32),
160 .digestsize = CHKSUM_DIGEST_SIZE,
161 .base = {
162 .cra_name = "crc32",
163 .cra_driver_name = "crc32-pclmul",
164 .cra_priority = 200,
165 .cra_blocksize = CHKSUM_BLOCK_SIZE,
166 .cra_ctxsize = sizeof(u32),
167 .cra_module = THIS_MODULE,
168 .cra_init = crc32_pclmul_cra_init,
169 }
170 };
171
172 static const struct x86_cpu_id crc32pclmul_cpu_id[] = {
173 X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ),
174 {}
175 };
176 MODULE_DEVICE_TABLE(x86cpu, crc32pclmul_cpu_id);
177
178
crc32_pclmul_mod_init(void)179 static int __init crc32_pclmul_mod_init(void)
180 {
181
182 if (!x86_match_cpu(crc32pclmul_cpu_id)) {
183 pr_info("PCLMULQDQ-NI instructions are not detected.\n");
184 return -ENODEV;
185 }
186 return crypto_register_shash(&alg);
187 }
188
crc32_pclmul_mod_fini(void)189 static void __exit crc32_pclmul_mod_fini(void)
190 {
191 crypto_unregister_shash(&alg);
192 }
193
194 module_init(crc32_pclmul_mod_init);
195 module_exit(crc32_pclmul_mod_fini);
196
197 MODULE_AUTHOR("Alexander Boyko <alexander_boyko@xyratex.com>");
198 MODULE_LICENSE("GPL");
199
200 MODULE_ALIAS_CRYPTO("crc32");
201 MODULE_ALIAS_CRYPTO("crc32-pclmul");
202