1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Calculate a CRC T10-DIF with vpmsum acceleration |
4 | * |
5 | * Copyright 2017, Daniel Axtens, IBM Corporation. |
6 | * [based on crc32c-vpmsum_glue.c] |
7 | */ |
8 | |
9 | #include <linux/crc-t10dif.h> |
10 | #include <crypto/internal/hash.h> |
11 | #include <crypto/internal/simd.h> |
12 | #include <linux/init.h> |
13 | #include <linux/module.h> |
14 | #include <linux/string.h> |
15 | #include <linux/kernel.h> |
16 | #include <linux/cpufeature.h> |
17 | #include <asm/simd.h> |
18 | #include <asm/switch_to.h> |
19 | |
20 | #define VMX_ALIGN 16 |
21 | #define VMX_ALIGN_MASK (VMX_ALIGN-1) |
22 | |
23 | #define VECTOR_BREAKPOINT 64 |
24 | |
25 | u32 __crct10dif_vpmsum(u32 crc, unsigned char const *p, size_t len); |
26 | |
27 | static u16 crct10dif_vpmsum(u16 crci, unsigned char const *p, size_t len) |
28 | { |
29 | unsigned int prealign; |
30 | unsigned int tail; |
31 | u32 crc = crci; |
32 | |
33 | if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable()) |
34 | return crc_t10dif_generic(crc, buffer: p, len); |
35 | |
36 | if ((unsigned long)p & VMX_ALIGN_MASK) { |
37 | prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK); |
38 | crc = crc_t10dif_generic(crc, buffer: p, len: prealign); |
39 | len -= prealign; |
40 | p += prealign; |
41 | } |
42 | |
43 | if (len & ~VMX_ALIGN_MASK) { |
44 | crc <<= 16; |
45 | preempt_disable(); |
46 | pagefault_disable(); |
47 | enable_kernel_altivec(); |
48 | crc = __crct10dif_vpmsum(crc, p, len: len & ~VMX_ALIGN_MASK); |
49 | disable_kernel_altivec(); |
50 | pagefault_enable(); |
51 | preempt_enable(); |
52 | crc >>= 16; |
53 | } |
54 | |
55 | tail = len & VMX_ALIGN_MASK; |
56 | if (tail) { |
57 | p += len & ~VMX_ALIGN_MASK; |
58 | crc = crc_t10dif_generic(crc, buffer: p, len: tail); |
59 | } |
60 | |
61 | return crc & 0xffff; |
62 | } |
63 | |
64 | static int crct10dif_vpmsum_init(struct shash_desc *desc) |
65 | { |
66 | u16 *crc = shash_desc_ctx(desc); |
67 | |
68 | *crc = 0; |
69 | return 0; |
70 | } |
71 | |
72 | static int crct10dif_vpmsum_update(struct shash_desc *desc, const u8 *data, |
73 | unsigned int length) |
74 | { |
75 | u16 *crc = shash_desc_ctx(desc); |
76 | |
77 | *crc = crct10dif_vpmsum(crci: *crc, p: data, len: length); |
78 | |
79 | return 0; |
80 | } |
81 | |
82 | |
83 | static int crct10dif_vpmsum_final(struct shash_desc *desc, u8 *out) |
84 | { |
85 | u16 *crcp = shash_desc_ctx(desc); |
86 | |
87 | *(u16 *)out = *crcp; |
88 | return 0; |
89 | } |
90 | |
91 | static struct shash_alg alg = { |
92 | .init = crct10dif_vpmsum_init, |
93 | .update = crct10dif_vpmsum_update, |
94 | .final = crct10dif_vpmsum_final, |
95 | .descsize = CRC_T10DIF_DIGEST_SIZE, |
96 | .digestsize = CRC_T10DIF_DIGEST_SIZE, |
97 | .base = { |
98 | .cra_name = "crct10dif" , |
99 | .cra_driver_name = "crct10dif-vpmsum" , |
100 | .cra_priority = 200, |
101 | .cra_blocksize = CRC_T10DIF_BLOCK_SIZE, |
102 | .cra_module = THIS_MODULE, |
103 | } |
104 | }; |
105 | |
106 | static int __init crct10dif_vpmsum_mod_init(void) |
107 | { |
108 | if (!cpu_has_feature(CPU_FTR_ARCH_207S)) |
109 | return -ENODEV; |
110 | |
111 | return crypto_register_shash(alg: &alg); |
112 | } |
113 | |
114 | static void __exit crct10dif_vpmsum_mod_fini(void) |
115 | { |
116 | crypto_unregister_shash(alg: &alg); |
117 | } |
118 | |
119 | module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crct10dif_vpmsum_mod_init); |
120 | module_exit(crct10dif_vpmsum_mod_fini); |
121 | |
122 | MODULE_AUTHOR("Daniel Axtens <dja@axtens.net>" ); |
123 | MODULE_DESCRIPTION("CRCT10DIF using vector polynomial multiply-sum instructions" ); |
124 | MODULE_LICENSE("GPL" ); |
125 | MODULE_ALIAS_CRYPTO("crct10dif" ); |
126 | MODULE_ALIAS_CRYPTO("crct10dif-vpmsum" ); |
127 | |