summaryrefslogtreecommitdiffstats
path: root/arch/x86/crypto/crc32c-intel_glue.c
blob: c194d5717ae51e31e0f57170194adf0bce56ea5e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
/*
 * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
 * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
 * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
 * http://www.intel.com/products/processor/manuals/
 * Intel(R) 64 and IA-32 Architectures Software Developer's Manual
 * Volume 2A: Instruction Set Reference, A-M
 *
 * Copyright (C) 2008 Intel Corporation
 * Authors: Austin Zhang <austin_zhang@linux.intel.com>
 *          Kent Liu <kent.liu@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <crypto/internal/hash.h>

#include <asm/cpufeatures.h>
#include <asm/cpu_device_id.h>
#include <asm/fpu/internal.h>

#define CHKSUM_BLOCK_SIZE	1
#define CHKSUM_DIGEST_SIZE	4

#define SCALE_F	sizeof(unsigned long)

#ifdef CONFIG_X86_64
#define REX_PRE "0x48, "
#else
#define REX_PRE
#endif

#ifdef CONFIG_X86_64
/*
 * use carryless multiply version of crc32c when buffer
 * size is >= 512 to account
 * for fpu state save/restore overhead.
 */
#define CRC32C_PCL_BREAKEVEN	512

asmlinkage unsigned int crc_pcl(const u8 *buffer, int len,
				unsigned int crc_init);
#endif /* CONFIG_X86_64 */

static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length)
{
	while (length--) {
		__asm__ __volatile__(
			".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
			:"=S"(crc)
			:"0"(crc), "c"(*data)
		);
		data++;
	}

	return crc;
}

static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len)
{
	unsigned int iquotient = len / SCALE_F;
	unsigned int iremainder = len % SCALE_F;
	unsigned long *ptmp = (unsigned long *)p;

	while (iquotient--) {
		__asm__ __volatile__(
			".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
			:"=S"(crc)
			:"0"(crc), "c"(*ptmp)
		);
		ptmp++;
	}

	if (iremainder)
		crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
				 iremainder);

	return crc;
}

/*
 * Setting the seed allows arbitrary accumulators and flexible XOR policy
 * If your algorithm starts with ~0, then XOR with ~0 before you set
 * the seed.
 */
static int crc32c_intel_setkey(struct crypto_shash *hash, const u8 *key,
			unsigned int keylen)
{
	u32 *mctx = crypto_shash_ctx(hash);

	if (keylen != sizeof(u32)) {
		crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}
	*mctx = le32_to_cpup((__le32 *)key);
	return 0;
}

static int crc32c_intel_init(struct shash_desc *desc)
{
	u32 *mctx = crypto_shash_ctx(desc->tfm);
	u32 *crcp = shash_desc_ctx(desc);

	*crcp = *mctx;

	return 0;
}

static int crc32c_intel_update(struct shash_desc *desc, const u8 *data,
			       unsigned int len)
{
	u32 *crcp = shash_desc_ctx(desc);

	*crcp = crc32c_intel_le_hw(*crcp, data, len);
	return 0;
}

static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
				u8 *out)
{
	*(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
	return 0;
}

static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data,
			      unsigned int len, u8 *out)
{
	return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out);
}

static int crc32c_intel_final(struct shash_desc *desc, u8 *out)
{
	u32 *crcp = shash_desc_ctx(desc);

	*(__le32 *)out = ~cpu_to_le32p(crcp);
	return 0;
}

static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data,
			       unsigned int len, u8 *out)
{
	return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
				    out);
}

static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
{
	u32 *key = crypto_tfm_ctx(tfm);

	*key = ~0;

	return 0;
}

#ifdef CONFIG_X86_64
static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data,
			       unsigned int len)
{
	u32 *crcp = shash_desc_ctx(desc);

	/*
	 * use faster PCL version if datasize is large enough to
	 * overcome kernel fpu state save/restore overhead
	 */
	if (len >= CRC32C_PCL_BREAKEVEN && irq_fpu_usable()) {
		kernel_fpu_begin();
		*crcp = crc_pcl(data, len, *crcp);
		kernel_fpu_end();
	} else
		*crcp = crc32c_intel_le_hw(*crcp, data, len);
	return 0;
}

static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len,
				u8 *out)
{
	if (len >= CRC32C_PCL_BREAKEVEN && irq_fpu_usable()) {
		kernel_fpu_begin();
		*(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp));
		kernel_fpu_end();
	} else
		*(__le32 *)out =
			~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len));
	return 0;
}

static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data,
			      unsigned int len, u8 *out)
{
	return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out);
}

static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data,
			       unsigned int len, u8 *out)
{
	return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len,
				    out);
}
#endif /* CONFIG_X86_64 */

static struct shash_alg alg = {
	.setkey			=	crc32c_intel_setkey,
	.init			=	crc32c_intel_init,
	.update			=	crc32c_intel_update,
	.final			=	crc32c_intel_final,
	.finup			=	crc32c_intel_finup,
	.digest			=	crc32c_intel_digest,
	.descsize		=	sizeof(u32),
	.digestsize		=	CHKSUM_DIGEST_SIZE,
	.base			=	{
		.cra_name		=	"crc32c",
		.cra_driver_name	=	"crc32c-intel",
		.cra_priority		=	200,
		.cra_blocksize		=	CHKSUM_BLOCK_SIZE,
		.cra_ctxsize		=	sizeof(u32),
		.cra_module		=	THIS_MODULE,
		.cra_init		=	crc32c_intel_cra_init,
	}
};

static const struct x86_cpu_id crc32c_cpu_id[] = {
	X86_FEATURE_MATCH(X86_FEATURE_XMM4_2),
	{}
};
MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id);

static int __init crc32c_intel_mod_init(void)
{
	if (!x86_match_cpu(crc32c_cpu_id))
		return -ENODEV;
#ifdef CONFIG_X86_64
	if (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) {
		alg.update = crc32c_pcl_intel_update;
		alg.finup = crc32c_pcl_intel_finup;
		alg.digest = crc32c_pcl_intel_digest;
	}
#endif
	return crypto_register_shash(&alg);
}

static void __exit crc32c_intel_mod_fini(void)
{
	crypto_unregister_shash(&alg);
}

module_init(crc32c_intel_mod_init);
module_exit(crc32c_intel_mod_fini);

MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>");
MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware.");
MODULE_LICENSE("GPL");

MODULE_ALIAS_CRYPTO("crc32c");
MODULE_ALIAS_CRYPTO("crc32c-intel");