Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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 Intel Corporation
10  * Authors: Austin Zhang <austin_zhang@linux.intel.com>
11  *          Kent Liu <kent.liu@intel.com>
12  *
13  * This program is free software; you can redistribute it and/or modify it
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.
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_shash *hash, const u8 *key,
88                         unsigned int keylen)
89 {
90         u32 *mctx = crypto_shash_ctx(hash);
91
92         if (keylen != sizeof(u32)) {
93                 crypto_shash_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 shash_desc *desc)
101 {
102         u32 *mctx = crypto_shash_ctx(desc->tfm);
103         u32 *crcp = shash_desc_ctx(desc);
104
105         *crcp = *mctx;
106
107         return 0;
108 }
109
110 static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
111                                unsigned int len)
112 {
113         u32 *crcp = shash_desc_ctx(desc);
114
115         *crcp = crc32c_intel_le_hw(*crcp, data, len);
116         return 0;
117 }
118
119 static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
120                                 u8 *out)
121 {
122         *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
123         return 0;
124 }
125
126 static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
127                               unsigned int len, u8 *out)
128 {
129         return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
130 }
131
132 static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
133 {
134         u32 *crcp = shash_desc_ctx(desc);
135
136         *(__le32 *)out = ~cpu_to_le32p(crcp);
137         return 0;
138 }
139
140 static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
141                                unsigned int len, u8 *out)
142 {
143         return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
144                                     out);
145 }
146
147 static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
148 {
149         u32 *key = crypto_tfm_ctx(tfm);
150
151         *key = ~0;
152
153         return 0;
154 }
155
156 static struct shash_alg alg = {
157         .setkey                 =       crc32c_intel_setkey,
158         .init                   =       crc32c_intel_init,
159         .update                 =       crc32c_intel_update,
160         .final                  =       crc32c_intel_final,
161         .finup                  =       crc32c_intel_finup,
162         .digest                 =       crc32c_intel_digest,
163         .descsize               =       sizeof(u32),
164         .digestsize             =       CHKSUM_DIGEST_SIZE,
165         .base                   =       {
166                 .cra_name               =       "crc32c",
167                 .cra_driver_name        =       "crc32c-intel",
168                 .cra_priority           =       200,
169                 .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
170                 .cra_ctxsize            =       sizeof(u32),
171                 .cra_module             =       THIS_MODULE,
172                 .cra_init               =       crc32c_intel_cra_init,
173         }
174 };
175
176
177 static int __init crc32c_intel_mod_init(void)
178 {
179         if (cpu_has_xmm4_2)
180                 return crypto_register_shash(&alg);
181         else
182                 return -ENODEV;
183 }
184
185 static void __exit crc32c_intel_mod_fini(void)
186 {
187         crypto_unregister_shash(&alg);
188 }
189
190 module_init(crc32c_intel_mod_init);
191 module_exit(crc32c_intel_mod_fini);
192
193 MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
194 MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
195 MODULE_LICENSE("GPL");
196
197 MODULE_ALIAS("crc32c");
198 MODULE_ALIAS("crc32c-intel");