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1 | /* |
2 | * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. | |
3 | * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) | |
4 | * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: | |
5 | * http://www.intel.com/products/processor/manuals/ | |
6 | * Intel(R) 64 and IA-32 Architectures Software Developer's Manual | |
7 | * Volume 2A: Instruction Set Reference, A-M | |
8 | * | |
1c06da81 KL |
9 | * Copyright (C) 2008 Intel Corporation |
10 | * Authors: Austin Zhang <austin_zhang@linux.intel.com> | |
11 | * Kent Liu <kent.liu@intel.com> | |
8cb51ba8 AZ |
12 | * |
13 | * This program is free software; you can redistribute it and/or modify it | |
1c06da81 KL |
14 | * under the terms and conditions of the GNU General Public License, |
15 | * version 2, as published by the Free Software Foundation. | |
16 | * | |
17 | * This program is distributed in the hope it will be useful, but WITHOUT | |
18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
20 | * more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License along with | |
23 | * this program; if not, write to the Free Software Foundation, Inc., | |
24 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
8cb51ba8 AZ |
25 | * |
26 | */ | |
27 | #include <linux/init.h> | |
28 | #include <linux/module.h> | |
29 | #include <linux/string.h> | |
30 | #include <linux/kernel.h> | |
31 | #include <crypto/internal/hash.h> | |
32 | ||
33 | #include <asm/cpufeature.h> | |
34 | ||
35 | #define CHKSUM_BLOCK_SIZE 1 | |
36 | #define CHKSUM_DIGEST_SIZE 4 | |
37 | ||
38 | #define SCALE_F sizeof(unsigned long) | |
39 | ||
40 | #ifdef CONFIG_X86_64 | |
41 | #define REX_PRE "0x48, " | |
42 | #else | |
43 | #define REX_PRE | |
44 | #endif | |
45 | ||
46 | static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length) | |
47 | { | |
48 | while (length--) { | |
49 | __asm__ __volatile__( | |
50 | ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" | |
51 | :"=S"(crc) | |
52 | :"0"(crc), "c"(*data) | |
53 | ); | |
54 | data++; | |
55 | } | |
56 | ||
57 | return crc; | |
58 | } | |
59 | ||
60 | static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len) | |
61 | { | |
62 | unsigned int iquotient = len / SCALE_F; | |
63 | unsigned int iremainder = len % SCALE_F; | |
64 | unsigned long *ptmp = (unsigned long *)p; | |
65 | ||
66 | while (iquotient--) { | |
67 | __asm__ __volatile__( | |
68 | ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" | |
69 | :"=S"(crc) | |
70 | :"0"(crc), "c"(*ptmp) | |
71 | ); | |
72 | ptmp++; | |
73 | } | |
74 | ||
75 | if (iremainder) | |
76 | crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, | |
77 | iremainder); | |
78 | ||
79 | return crc; | |
80 | } | |
81 | ||
82 | /* | |
83 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
84 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
85 | * the seed. | |
86 | */ | |
87 | static int crc32c_intel_setkey(struct crypto_ahash *hash, const u8 *key, | |
88 | unsigned int keylen) | |
89 | { | |
90 | u32 *mctx = crypto_ahash_ctx(hash); | |
91 | ||
92 | if (keylen != sizeof(u32)) { | |
93 | crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
94 | return -EINVAL; | |
95 | } | |
96 | *mctx = le32_to_cpup((__le32 *)key); | |
97 | return 0; | |
98 | } | |
99 | ||
100 | static int crc32c_intel_init(struct ahash_request *req) | |
101 | { | |
102 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
103 | u32 *crcp = ahash_request_ctx(req); | |
104 | ||
105 | *crcp = *mctx; | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
110 | static int crc32c_intel_update(struct ahash_request *req) | |
111 | { | |
112 | struct crypto_hash_walk walk; | |
113 | u32 *crcp = ahash_request_ctx(req); | |
114 | u32 crc = *crcp; | |
115 | int nbytes; | |
116 | ||
117 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
118 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
119 | crc = crc32c_intel_le_hw(crc, walk.data, nbytes); | |
120 | ||
121 | *crcp = crc; | |
122 | return 0; | |
123 | } | |
124 | ||
125 | static int crc32c_intel_final(struct ahash_request *req) | |
126 | { | |
127 | u32 *crcp = ahash_request_ctx(req); | |
128 | ||
129 | *(__le32 *)req->result = ~cpu_to_le32p(crcp); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | static int crc32c_intel_digest(struct ahash_request *req) | |
134 | { | |
135 | struct crypto_hash_walk walk; | |
136 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
137 | u32 crc = *mctx; | |
138 | int nbytes; | |
139 | ||
140 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
141 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
142 | crc = crc32c_intel_le_hw(crc, walk.data, nbytes); | |
143 | ||
144 | *(__le32 *)req->result = ~cpu_to_le32(crc); | |
145 | return 0; | |
146 | } | |
147 | ||
148 | static int crc32c_intel_cra_init(struct crypto_tfm *tfm) | |
149 | { | |
150 | u32 *key = crypto_tfm_ctx(tfm); | |
151 | ||
152 | *key = ~0; | |
153 | ||
154 | tfm->crt_ahash.reqsize = sizeof(u32); | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | static struct crypto_alg alg = { | |
160 | .cra_name = "crc32c", | |
161 | .cra_driver_name = "crc32c-intel", | |
162 | .cra_priority = 200, | |
163 | .cra_flags = CRYPTO_ALG_TYPE_AHASH, | |
164 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
165 | .cra_alignmask = 3, | |
166 | .cra_ctxsize = sizeof(u32), | |
167 | .cra_module = THIS_MODULE, | |
168 | .cra_list = LIST_HEAD_INIT(alg.cra_list), | |
169 | .cra_init = crc32c_intel_cra_init, | |
170 | .cra_type = &crypto_ahash_type, | |
171 | .cra_u = { | |
172 | .ahash = { | |
173 | .digestsize = CHKSUM_DIGEST_SIZE, | |
174 | .setkey = crc32c_intel_setkey, | |
175 | .init = crc32c_intel_init, | |
176 | .update = crc32c_intel_update, | |
177 | .final = crc32c_intel_final, | |
178 | .digest = crc32c_intel_digest, | |
179 | } | |
180 | } | |
181 | }; | |
182 | ||
183 | ||
184 | static int __init crc32c_intel_mod_init(void) | |
185 | { | |
186 | if (cpu_has_xmm4_2) | |
187 | return crypto_register_alg(&alg); | |
188 | else | |
189 | return -ENODEV; | |
190 | } | |
191 | ||
192 | static void __exit crc32c_intel_mod_fini(void) | |
193 | { | |
194 | crypto_unregister_alg(&alg); | |
195 | } | |
196 | ||
197 | module_init(crc32c_intel_mod_init); | |
198 | module_exit(crc32c_intel_mod_fini); | |
199 | ||
200 | MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>"); | |
201 | MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware."); | |
202 | MODULE_LICENSE("GPL"); | |
203 | ||
204 | MODULE_ALIAS("crc32c"); | |
205 | MODULE_ALIAS("crc32c-intel"); |