tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/crc32.h>
2#include <crypto/internal/hash.h>
3#include <linux/init.h>
4#include <linux/module.h>
5#include <linux/string.h>
6#include <linux/kernel.h>
7#include <linux/cpufeature.h>
8#include <asm/switch_to.h>
9
10#define CHKSUM_BLOCK_SIZE 1
11#define CHKSUM_DIGEST_SIZE 4
12
13#define VMX_ALIGN 16
14#define VMX_ALIGN_MASK (VMX_ALIGN-1)
15
16#define VECTOR_BREAKPOINT 512
17
18u32 __crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len);
19
20static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len)
21{
22 unsigned int prealign;
23 unsigned int tail;
24
25 if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || in_interrupt())
26 return __crc32c_le(crc, p, len);
27
28 if ((unsigned long)p & VMX_ALIGN_MASK) {
29 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
30 crc = __crc32c_le(crc, p, prealign);
31 len -= prealign;
32 p += prealign;
33 }
34
35 if (len & ~VMX_ALIGN_MASK) {
36 preempt_disable();
37 pagefault_disable();
38 enable_kernel_altivec();
39 crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
40 disable_kernel_altivec();
41 pagefault_enable();
42 preempt_enable();
43 }
44
45 tail = len & VMX_ALIGN_MASK;
46 if (tail) {
47 p += len & ~VMX_ALIGN_MASK;
48 crc = __crc32c_le(crc, p, tail);
49 }
50
51 return crc;
52}
53
54static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
55{
56 u32 *key = crypto_tfm_ctx(tfm);
57
58 *key = ~0;
59
60 return 0;
61}
62
63/*
64 * Setting the seed allows arbitrary accumulators and flexible XOR policy
65 * If your algorithm starts with ~0, then XOR with ~0 before you set
66 * the seed.
67 */
68static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
69 unsigned int keylen)
70{
71 u32 *mctx = crypto_shash_ctx(hash);
72
73 if (keylen != sizeof(u32)) {
74 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
75 return -EINVAL;
76 }
77 *mctx = le32_to_cpup((__le32 *)key);
78 return 0;
79}
80
81static int crc32c_vpmsum_init(struct shash_desc *desc)
82{
83 u32 *mctx = crypto_shash_ctx(desc->tfm);
84 u32 *crcp = shash_desc_ctx(desc);
85
86 *crcp = *mctx;
87
88 return 0;
89}
90
91static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
92 unsigned int len)
93{
94 u32 *crcp = shash_desc_ctx(desc);
95
96 *crcp = crc32c_vpmsum(*crcp, data, len);
97
98 return 0;
99}
100
101static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
102 u8 *out)
103{
104 *(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
105
106 return 0;
107}
108
109static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
110 unsigned int len, u8 *out)
111{
112 return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
113}
114
115static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
116{
117 u32 *crcp = shash_desc_ctx(desc);
118
119 *(__le32 *)out = ~cpu_to_le32p(crcp);
120
121 return 0;
122}
123
124static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
125 unsigned int len, u8 *out)
126{
127 return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
128 out);
129}
130
131static struct shash_alg alg = {
132 .setkey = crc32c_vpmsum_setkey,
133 .init = crc32c_vpmsum_init,
134 .update = crc32c_vpmsum_update,
135 .final = crc32c_vpmsum_final,
136 .finup = crc32c_vpmsum_finup,
137 .digest = crc32c_vpmsum_digest,
138 .descsize = sizeof(u32),
139 .digestsize = CHKSUM_DIGEST_SIZE,
140 .base = {
141 .cra_name = "crc32c",
142 .cra_driver_name = "crc32c-vpmsum",
143 .cra_priority = 200,
144 .cra_blocksize = CHKSUM_BLOCK_SIZE,
145 .cra_ctxsize = sizeof(u32),
146 .cra_module = THIS_MODULE,
147 .cra_init = crc32c_vpmsum_cra_init,
148 }
149};
150
151static int __init crc32c_vpmsum_mod_init(void)
152{
153 if (!cpu_has_feature(CPU_FTR_ARCH_207S))
154 return -ENODEV;
155
156 return crypto_register_shash(&alg);
157}
158
159static void __exit crc32c_vpmsum_mod_fini(void)
160{
161 crypto_unregister_shash(&alg);
162}
163
164module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
165module_exit(crc32c_vpmsum_mod_fini);
166
167MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
168MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
169MODULE_LICENSE("GPL");
170MODULE_ALIAS_CRYPTO("crc32c");
171MODULE_ALIAS_CRYPTO("crc32c-vpmsum");