1/*
2 * Cryptographic API.
3 *
4 * T10 Data Integrity Field CRC16 Crypto Transform using PCLMULQDQ Instructions
5 *
6 * Copyright (C) 2013 Intel Corporation
7 * Author: Tim Chen <tim.c.chen@linux.intel.com>
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the Free
11 * Software Foundation; either version 2 of the License, or (at your option)
12 * any later version.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
18 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
19 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 * SOFTWARE.
22 *
23 */
24
25#include <linux/types.h>
26#include <linux/module.h>
27#include <linux/crc-t10dif.h>
28#include <crypto/internal/hash.h>
29#include <linux/init.h>
30#include <linux/string.h>
31#include <linux/kernel.h>
32#include <asm/fpu/api.h>
33#include <asm/cpufeature.h>
34#include <asm/cpu_device_id.h>
35
36asmlinkage __u16 crc_t10dif_pcl(__u16 crc, const unsigned char *buf,
37				size_t len);
38
39struct chksum_desc_ctx {
40	__u16 crc;
41};
42
43/*
44 * Steps through buffer one byte at at time, calculates reflected
45 * crc using table.
46 */
47
48static int chksum_init(struct shash_desc *desc)
49{
50	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
51
52	ctx->crc = 0;
53
54	return 0;
55}
56
57static int chksum_update(struct shash_desc *desc, const u8 *data,
58			 unsigned int length)
59{
60	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
61
62	if (irq_fpu_usable()) {
63		kernel_fpu_begin();
64		ctx->crc = crc_t10dif_pcl(ctx->crc, data, length);
65		kernel_fpu_end();
66	} else
67		ctx->crc = crc_t10dif_generic(ctx->crc, data, length);
68	return 0;
69}
70
71static int chksum_final(struct shash_desc *desc, u8 *out)
72{
73	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
74
75	*(__u16 *)out = ctx->crc;
76	return 0;
77}
78
79static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
80			u8 *out)
81{
82	if (irq_fpu_usable()) {
83		kernel_fpu_begin();
84		*(__u16 *)out = crc_t10dif_pcl(*crcp, data, len);
85		kernel_fpu_end();
86	} else
87		*(__u16 *)out = crc_t10dif_generic(*crcp, data, len);
88	return 0;
89}
90
91static int chksum_finup(struct shash_desc *desc, const u8 *data,
92			unsigned int len, u8 *out)
93{
94	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
95
96	return __chksum_finup(&ctx->crc, data, len, out);
97}
98
99static int chksum_digest(struct shash_desc *desc, const u8 *data,
100			 unsigned int length, u8 *out)
101{
102	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
103
104	return __chksum_finup(&ctx->crc, data, length, out);
105}
106
107static struct shash_alg alg = {
108	.digestsize		=	CRC_T10DIF_DIGEST_SIZE,
109	.init		=	chksum_init,
110	.update		=	chksum_update,
111	.final		=	chksum_final,
112	.finup		=	chksum_finup,
113	.digest		=	chksum_digest,
114	.descsize		=	sizeof(struct chksum_desc_ctx),
115	.base			=	{
116		.cra_name		=	"crct10dif",
117		.cra_driver_name	=	"crct10dif-pclmul",
118		.cra_priority		=	200,
119		.cra_blocksize		=	CRC_T10DIF_BLOCK_SIZE,
120		.cra_module		=	THIS_MODULE,
121	}
122};
123
124static const struct x86_cpu_id crct10dif_cpu_id[] = {
125	X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ),
126	{}
127};
128MODULE_DEVICE_TABLE(x86cpu, crct10dif_cpu_id);
129
130static int __init crct10dif_intel_mod_init(void)
131{
132	if (!x86_match_cpu(crct10dif_cpu_id))
133		return -ENODEV;
134
135	return crypto_register_shash(&alg);
136}
137
138static void __exit crct10dif_intel_mod_fini(void)
139{
140	crypto_unregister_shash(&alg);
141}
142
143module_init(crct10dif_intel_mod_init);
144module_exit(crct10dif_intel_mod_fini);
145
146MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
147MODULE_DESCRIPTION("T10 DIF CRC calculation accelerated with PCLMULQDQ.");
148MODULE_LICENSE("GPL");
149
150MODULE_ALIAS_CRYPTO("crct10dif");
151MODULE_ALIAS_CRYPTO("crct10dif-pclmul");
152