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/cpufeatures.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");