crypto: crc32c - Use Intel CRC32 instruction
[linux-2.6.git] / arch / x86 / crypto / crc32c-intel.c
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