1 /*
2  * Accelerated CRC-T10DIF using arm64 NEON and Crypto Extensions instructions
3  *
4  * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #include <linux/cpufeature.h>
12 #include <linux/crc-t10dif.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/string.h>
17 
18 #include <crypto/internal/hash.h>
19 
20 #include <asm/neon.h>
21 
22 #define CRC_T10DIF_PMULL_CHUNK_SIZE	16U
23 
24 asmlinkage u16 crc_t10dif_pmull(u16 init_crc, const u8 buf[], u64 len);
25 
26 static int crct10dif_init(struct shash_desc *desc)
27 {
28 	u16 *crc = shash_desc_ctx(desc);
29 
30 	*crc = 0;
31 	return 0;
32 }
33 
34 static int crct10dif_update(struct shash_desc *desc, const u8 *data,
35 			    unsigned int length)
36 {
37 	u16 *crc = shash_desc_ctx(desc);
38 	unsigned int l;
39 
40 	if (unlikely((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE)) {
41 		l = min_t(u32, length, CRC_T10DIF_PMULL_CHUNK_SIZE -
42 			  ((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE));
43 
44 		*crc = crc_t10dif_generic(*crc, data, l);
45 
46 		length -= l;
47 		data += l;
48 	}
49 
50 	if (length > 0) {
51 		kernel_neon_begin_partial(14);
52 		*crc = crc_t10dif_pmull(*crc, data, length);
53 		kernel_neon_end();
54 	}
55 
56 	return 0;
57 }
58 
59 static int crct10dif_final(struct shash_desc *desc, u8 *out)
60 {
61 	u16 *crc = shash_desc_ctx(desc);
62 
63 	*(u16 *)out = *crc;
64 	return 0;
65 }
66 
67 static struct shash_alg crc_t10dif_alg = {
68 	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
69 	.init			= crct10dif_init,
70 	.update			= crct10dif_update,
71 	.final			= crct10dif_final,
72 	.descsize		= CRC_T10DIF_DIGEST_SIZE,
73 
74 	.base.cra_name		= "crct10dif",
75 	.base.cra_driver_name	= "crct10dif-arm64-ce",
76 	.base.cra_priority	= 200,
77 	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
78 	.base.cra_module	= THIS_MODULE,
79 };
80 
81 static int __init crc_t10dif_mod_init(void)
82 {
83 	return crypto_register_shash(&crc_t10dif_alg);
84 }
85 
86 static void __exit crc_t10dif_mod_exit(void)
87 {
88 	crypto_unregister_shash(&crc_t10dif_alg);
89 }
90 
91 module_cpu_feature_match(PMULL, crc_t10dif_mod_init);
92 module_exit(crc_t10dif_mod_exit);
93 
94 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
95 MODULE_LICENSE("GPL v2");
96