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
 37asmlinkage u16 crc_t10dif_pcl(u16 init_crc, const u8 *buf, size_t len);
 38
 39struct chksum_desc_ctx {
 40	__u16 crc;
 41};
 42
 43static 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
 52static 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
 66static 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
 74static 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
 85static 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
 93static 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
 99static 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
116static const struct x86_cpu_id crct10dif_cpu_id[] = {
117	X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL),
118	{}
119};
120MODULE_DEVICE_TABLE(x86cpu, crct10dif_cpu_id);
121
122static 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
130static void __exit crct10dif_intel_mod_fini(void)
131{
132	crypto_unregister_shash(&alg);
133}
134
135module_init(crct10dif_intel_mod_init);
136module_exit(crct10dif_intel_mod_fini);
137
138MODULE_AUTHOR("Tim Chen <tim.c.chen@linux.intel.com>");
139MODULE_DESCRIPTION("T10 DIF CRC calculation accelerated with PCLMULQDQ.");
140MODULE_LICENSE("GPL");
141
142MODULE_ALIAS_CRYPTO("crct10dif");
143MODULE_ALIAS_CRYPTO("crct10dif-pclmul");