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_p64(u16 init_crc, const u8 buf[], u64 len);
26 asmlinkage u16 crc_t10dif_pmull_p8(u16 init_crc, const u8 buf[], u64 len);
27 
28 static u16 (*crc_t10dif_pmull)(u16 init_crc, const u8 buf[], u64 len);
29 
30 static int crct10dif_init(struct shash_desc *desc)
31 {
32 	u16 *crc = shash_desc_ctx(desc);
33 
34 	*crc = 0;
35 	return 0;
36 }
37 
38 static int crct10dif_update(struct shash_desc *desc, const u8 *data,
39 			    unsigned int length)
40 {
41 	u16 *crc = shash_desc_ctx(desc);
42 	unsigned int l;
43 
44 	if (unlikely((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE)) {
45 		l = min_t(u32, length, CRC_T10DIF_PMULL_CHUNK_SIZE -
46 			  ((u64)data % CRC_T10DIF_PMULL_CHUNK_SIZE));
47 
48 		*crc = crc_t10dif_generic(*crc, data, l);
49 
50 		length -= l;
51 		data += l;
52 	}
53 
54 	if (length > 0) {
55 		if (may_use_simd()) {
56 			kernel_neon_begin();
57 			*crc = crc_t10dif_pmull(*crc, data, length);
58 			kernel_neon_end();
59 		} else {
60 			*crc = crc_t10dif_generic(*crc, data, length);
61 		}
62 	}
63 
64 	return 0;
65 }
66 
67 static int crct10dif_final(struct shash_desc *desc, u8 *out)
68 {
69 	u16 *crc = shash_desc_ctx(desc);
70 
71 	*(u16 *)out = *crc;
72 	return 0;
73 }
74 
75 static struct shash_alg crc_t10dif_alg = {
76 	.digestsize		= CRC_T10DIF_DIGEST_SIZE,
77 	.init			= crct10dif_init,
78 	.update			= crct10dif_update,
79 	.final			= crct10dif_final,
80 	.descsize		= CRC_T10DIF_DIGEST_SIZE,
81 
82 	.base.cra_name		= "crct10dif",
83 	.base.cra_driver_name	= "crct10dif-arm64-ce",
84 	.base.cra_priority	= 200,
85 	.base.cra_blocksize	= CRC_T10DIF_BLOCK_SIZE,
86 	.base.cra_module	= THIS_MODULE,
87 };
88 
89 static int __init crc_t10dif_mod_init(void)
90 {
91 	if (elf_hwcap & HWCAP_PMULL)
92 		crc_t10dif_pmull = crc_t10dif_pmull_p64;
93 	else
94 		crc_t10dif_pmull = crc_t10dif_pmull_p8;
95 
96 	return crypto_register_shash(&crc_t10dif_alg);
97 }
98 
99 static void __exit crc_t10dif_mod_exit(void)
100 {
101 	crypto_unregister_shash(&crc_t10dif_alg);
102 }
103 
104 module_cpu_feature_match(ASIMD, crc_t10dif_mod_init);
105 module_exit(crc_t10dif_mod_exit);
106 
107 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
108 MODULE_LICENSE("GPL v2");
109 MODULE_ALIAS_CRYPTO("crct10dif");
110 MODULE_ALIAS_CRYPTO("crct10dif-arm64-ce");
111