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 <crypto/internal/simd.h>
30 #include <linux/init.h>
31 #include <linux/string.h>
32 #include <linux/kernel.h>
33 #include <asm/cpufeatures.h>
34 #include <asm/cpu_device_id.h>
35 #include <asm/simd.h>
36 
37 asmlinkage u16 crc_t10dif_pcl(u16 init_crc, const u8 *buf, size_t len);
38 
39 struct chksum_desc_ctx {
40 	__u16 crc;
41 };
42 
43 static int chksum_init(struct shash_desc *desc)
44 {
45 	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
46 
47 	ctx->crc = 0;
48 
49 	return 0;
50 }
51 
52 static int chksum_update(struct shash_desc *desc, const u8 *data,
53 			 unsigned int length)
54 {
55 	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
56 
57 	if (length >= 16 && crypto_simd_usable()) {
58 		kernel_fpu_begin();
59 		ctx->crc = crc_t10dif_pcl(ctx->crc, data, length);
60 		kernel_fpu_end();
61 	} else
62 		ctx->crc = crc_t10dif_generic(ctx->crc, data, length);
63 	return 0;
64 }
65 
66 static int chksum_final(struct shash_desc *desc, u8 *out)
67 {
68 	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
69 
70 	*(__u16 *)out = ctx->crc;
71 	return 0;
72 }
73 
74 static int __chksum_finup(__u16 crc, const u8 *data, unsigned int len, u8 *out)
75 {
76 	if (len >= 16 && crypto_simd_usable()) {
77 		kernel_fpu_begin();
78 		*(__u16 *)out = crc_t10dif_pcl(crc, data, len);
79 		kernel_fpu_end();
80 	} else
81 		*(__u16 *)out = crc_t10dif_generic(crc, data, len);
82 	return 0;
83 }
84 
85 static int chksum_finup(struct shash_desc *desc, const u8 *data,
86 			unsigned int len, u8 *out)
87 {
88 	struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
89 
90 	return __chksum_finup(ctx->crc, data, len, out);
91 }
92 
93 static int chksum_digest(struct shash_desc *desc, const u8 *data,
94 			 unsigned int length, u8 *out)
95 {
96 	return __chksum_finup(0, data, length, out);
97 }
98 
99 static struct shash_alg alg = {
100 	.digestsize		=	CRC_T10DIF_DIGEST_SIZE,
101 	.init		=	chksum_init,
102 	.update		=	chksum_update,
103 	.final		=	chksum_final,
104 	.finup		=	chksum_finup,
105 	.digest		=	chksum_digest,
106 	.descsize		=	sizeof(struct chksum_desc_ctx),
107 	.base			=	{
108 		.cra_name		=	"crct10dif",
109 		.cra_driver_name	=	"crct10dif-pclmul",
110 		.cra_priority		=	200,
111 		.cra_blocksize		=	CRC_T10DIF_BLOCK_SIZE,
112 		.cra_module		=	THIS_MODULE,
113 	}
114 };
115 
116 static const struct x86_cpu_id crct10dif_cpu_id[] = {
117 	X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL),
118 	{}
119 };
120 MODULE_DEVICE_TABLE(x86cpu, crct10dif_cpu_id);
121 
122 static int __init crct10dif_intel_mod_init(void)
123 {
124 	if (!x86_match_cpu(crct10dif_cpu_id))
125 		return -ENODEV;
126 
127 	return crypto_register_shash(&alg);
128 }
129 
130 static void __exit crct10dif_intel_mod_fini(void)
131 {
132 	crypto_unregister_shash(&alg);
133 }
134 
135 module_init(crct10dif_intel_mod_init);
136 module_exit(crct10dif_intel_mod_fini);
137 
138 MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
139 MODULE_DESCRIPTION("T10 DIF CRC calculation accelerated with PCLMULQDQ.");
140 MODULE_LICENSE("GPL");
141 
142 MODULE_ALIAS_CRYPTO("crct10dif");
143 MODULE_ALIAS_CRYPTO("crct10dif-pclmul");
144