1 /*
2  * Accelerated CRC-T10DIF using arm64 NEON and Crypto Extensions instructions
3  *
4  * Copyright (C) 2016 - 2017 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 #include <asm/simd.h>
22 
23 #define CRC_T10DIF_PMULL_CHUNK_SIZE	16U
24 
25 asmlinkage u16 crc_t10dif_pmull(u16 init_crc, const u8 buf[], u64 len);
26 
27 static int crct10dif_init(struct shash_desc *desc)
28 {
29 	u16 *crc = shash_desc_ctx(desc);
30 
31 	*crc = 0;
32 	return 0;
33 }
34 
35 static int crct10dif_update(struct shash_desc *desc, const u8 *data,
36 			    unsigned int length)
37 {
38 	u16 *crc = shash_desc_ctx(desc);
39 	unsigned int l;
40 
41 	if (unlikely((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE)) {
42 		l = min_t(u32, length, CRC_T10DIF_PMULL_CHUNK_SIZE -
43 			  ((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE));
44 
45 		*crc = crc_t10dif_generic(*crc, data, l);
46 
47 		length -= l;
48 		data += l;
49 	}
50 
51 	if (length > 0) {
52 		if (may_use_simd()) {
53 			kernel_neon_begin();
54 			*crc = crc_t10dif_pmull(*crc, data, length);
55 			kernel_neon_end();
56 		} else {
57 			*crc = crc_t10dif_generic(*crc, data, length);
58 		}
59 	}
60 
61 	return 0;
62 }
63 
64 static int crct10dif_final(struct shash_desc *desc, u8 *out)
65 {
66 	u16 *crc = shash_desc_ctx(desc);
67 
68 	*(u16 *)out = *crc;
69 	return 0;
70 }
71 
72 static struct shash_alg crc_t10dif_alg = {
73 	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
74 	.init			= crct10dif_init,
75 	.update			= crct10dif_update,
76 	.final			= crct10dif_final,
77 	.descsize		= CRC_T10DIF_DIGEST_SIZE,
78 
79 	.base.cra_name		= "crct10dif",
80 	.base.cra_driver_name	= "crct10dif-arm64-ce",
81 	.base.cra_priority	= 200,
82 	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
83 	.base.cra_module	= THIS_MODULE,
84 };
85 
86 static int __init crc_t10dif_mod_init(void)
87 {
88 	return crypto_register_shash(&crc_t10dif_alg);
89 }
90 
91 static void __exit crc_t10dif_mod_exit(void)
92 {
93 	crypto_unregister_shash(&crc_t10dif_alg);
94 }
95 
96 module_cpu_feature_match(PMULL, crc_t10dif_mod_init);
97 module_exit(crc_t10dif_mod_exit);
98 
99 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
100 MODULE_LICENSE("GPL v2");
101