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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 | * | |
9 | * Copyright (c) 2008 Austin Zhang <austin_zhang@linux.intel.com> | |
10 | * Copyright (c) 2008 Kent Liu <kent.liu@intel.com> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify it | |
13 | * under the terms of the GNU General Public License as published by the Free | |
14 | * Software Foundation; either version 2 of the License, or (at your option) | |
15 | * any later version. | |
16 | * | |
17 | */ | |
18 | #include <linux/init.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/string.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <crypto/internal/hash.h> | |
23 | ||
24 | #include <asm/cpufeature.h> | |
25 | ||
26 | #define CHKSUM_BLOCK_SIZE 1 | |
27 | #define CHKSUM_DIGEST_SIZE 4 | |
28 | ||
29 | #define SCALE_F sizeof(unsigned long) | |
30 | ||
31 | #ifdef CONFIG_X86_64 | |
32 | #define REX_PRE "0x48, " | |
33 | #else | |
34 | #define REX_PRE | |
35 | #endif | |
36 | ||
37 | static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length) | |
38 | { | |
39 | while (length--) { | |
40 | __asm__ __volatile__( | |
41 | ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" | |
42 | :"=S"(crc) | |
43 | :"0"(crc), "c"(*data) | |
44 | ); | |
45 | data++; | |
46 | } | |
47 | ||
48 | return crc; | |
49 | } | |
50 | ||
51 | static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len) | |
52 | { | |
53 | unsigned int iquotient = len / SCALE_F; | |
54 | unsigned int iremainder = len % SCALE_F; | |
55 | unsigned long *ptmp = (unsigned long *)p; | |
56 | ||
57 | while (iquotient--) { | |
58 | __asm__ __volatile__( | |
59 | ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" | |
60 | :"=S"(crc) | |
61 | :"0"(crc), "c"(*ptmp) | |
62 | ); | |
63 | ptmp++; | |
64 | } | |
65 | ||
66 | if (iremainder) | |
67 | crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, | |
68 | iremainder); | |
69 | ||
70 | return crc; | |
71 | } | |
72 | ||
73 | /* | |
74 | * Setting the seed allows arbitrary accumulators and flexible XOR policy | |
75 | * If your algorithm starts with ~0, then XOR with ~0 before you set | |
76 | * the seed. | |
77 | */ | |
78 | static int crc32c_intel_setkey(struct crypto_ahash *hash, const u8 *key, | |
79 | unsigned int keylen) | |
80 | { | |
81 | u32 *mctx = crypto_ahash_ctx(hash); | |
82 | ||
83 | if (keylen != sizeof(u32)) { | |
84 | crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
85 | return -EINVAL; | |
86 | } | |
87 | *mctx = le32_to_cpup((__le32 *)key); | |
88 | return 0; | |
89 | } | |
90 | ||
91 | static int crc32c_intel_init(struct ahash_request *req) | |
92 | { | |
93 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
94 | u32 *crcp = ahash_request_ctx(req); | |
95 | ||
96 | *crcp = *mctx; | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | static int crc32c_intel_update(struct ahash_request *req) | |
102 | { | |
103 | struct crypto_hash_walk walk; | |
104 | u32 *crcp = ahash_request_ctx(req); | |
105 | u32 crc = *crcp; | |
106 | int nbytes; | |
107 | ||
108 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
109 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
110 | crc = crc32c_intel_le_hw(crc, walk.data, nbytes); | |
111 | ||
112 | *crcp = crc; | |
113 | return 0; | |
114 | } | |
115 | ||
116 | static int crc32c_intel_final(struct ahash_request *req) | |
117 | { | |
118 | u32 *crcp = ahash_request_ctx(req); | |
119 | ||
120 | *(__le32 *)req->result = ~cpu_to_le32p(crcp); | |
121 | return 0; | |
122 | } | |
123 | ||
124 | static int crc32c_intel_digest(struct ahash_request *req) | |
125 | { | |
126 | struct crypto_hash_walk walk; | |
127 | u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req)); | |
128 | u32 crc = *mctx; | |
129 | int nbytes; | |
130 | ||
131 | for (nbytes = crypto_hash_walk_first(req, &walk); nbytes; | |
132 | nbytes = crypto_hash_walk_done(&walk, 0)) | |
133 | crc = crc32c_intel_le_hw(crc, walk.data, nbytes); | |
134 | ||
135 | *(__le32 *)req->result = ~cpu_to_le32(crc); | |
136 | return 0; | |
137 | } | |
138 | ||
139 | static int crc32c_intel_cra_init(struct crypto_tfm *tfm) | |
140 | { | |
141 | u32 *key = crypto_tfm_ctx(tfm); | |
142 | ||
143 | *key = ~0; | |
144 | ||
145 | tfm->crt_ahash.reqsize = sizeof(u32); | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static struct crypto_alg alg = { | |
151 | .cra_name = "crc32c", | |
152 | .cra_driver_name = "crc32c-intel", | |
153 | .cra_priority = 200, | |
154 | .cra_flags = CRYPTO_ALG_TYPE_AHASH, | |
155 | .cra_blocksize = CHKSUM_BLOCK_SIZE, | |
156 | .cra_alignmask = 3, | |
157 | .cra_ctxsize = sizeof(u32), | |
158 | .cra_module = THIS_MODULE, | |
159 | .cra_list = LIST_HEAD_INIT(alg.cra_list), | |
160 | .cra_init = crc32c_intel_cra_init, | |
161 | .cra_type = &crypto_ahash_type, | |
162 | .cra_u = { | |
163 | .ahash = { | |
164 | .digestsize = CHKSUM_DIGEST_SIZE, | |
165 | .setkey = crc32c_intel_setkey, | |
166 | .init = crc32c_intel_init, | |
167 | .update = crc32c_intel_update, | |
168 | .final = crc32c_intel_final, | |
169 | .digest = crc32c_intel_digest, | |
170 | } | |
171 | } | |
172 | }; | |
173 | ||
174 | ||
175 | static int __init crc32c_intel_mod_init(void) | |
176 | { | |
177 | if (cpu_has_xmm4_2) | |
178 | return crypto_register_alg(&alg); | |
179 | else | |
180 | return -ENODEV; | |
181 | } | |
182 | ||
183 | static void __exit crc32c_intel_mod_fini(void) | |
184 | { | |
185 | crypto_unregister_alg(&alg); | |
186 | } | |
187 | ||
188 | module_init(crc32c_intel_mod_init); | |
189 | module_exit(crc32c_intel_mod_fini); | |
190 | ||
191 | MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>"); | |
192 | MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware."); | |
193 | MODULE_LICENSE("GPL"); | |
194 | ||
195 | MODULE_ALIAS("crc32c"); | |
196 | MODULE_ALIAS("crc32c-intel"); | |
197 |