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 pagefault_disable();
37 enable_kernel_altivec();
38 crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
39 pagefault_enable();
40 }
41
42 tail = len & VMX_ALIGN_MASK;
43 if (tail) {
44 p += len & ~VMX_ALIGN_MASK;
45 crc = __crc32c_le(crc, p, tail);
46 }
47
48 return crc;
49}
50
51static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
52{
53 u32 *key = crypto_tfm_ctx(tfm);
54
55 *key = 0;
56
57 return 0;
58}
59
60/*
61 * Setting the seed allows arbitrary accumulators and flexible XOR policy
62 * If your algorithm starts with ~0, then XOR with ~0 before you set
63 * the seed.
64 */
65static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
66 unsigned int keylen)
67{
68 u32 *mctx = crypto_shash_ctx(hash);
69
70 if (keylen != sizeof(u32)) {
71 crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
72 return -EINVAL;
73 }
74 *mctx = le32_to_cpup((__le32 *)key);
75 return 0;
76}
77
78static int crc32c_vpmsum_init(struct shash_desc *desc)
79{
80 u32 *mctx = crypto_shash_ctx(desc->tfm);
81 u32 *crcp = shash_desc_ctx(desc);
82
83 *crcp = *mctx;
84
85 return 0;
86}
87
88static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
89 unsigned int len)
90{
91 u32 *crcp = shash_desc_ctx(desc);
92
93 *crcp = crc32c_vpmsum(*crcp, data, len);
94
95 return 0;
96}
97
98static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
99 u8 *out)
100{
101 *(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
102
103 return 0;
104}
105
106static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
107 unsigned int len, u8 *out)
108{
109 return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
110}
111
112static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
113{
114 u32 *crcp = shash_desc_ctx(desc);
115
116 *(__le32 *)out = ~cpu_to_le32p(crcp);
117
118 return 0;
119}
120
121static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
122 unsigned int len, u8 *out)
123{
124 return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
125 out);
126}
127
128static struct shash_alg alg = {
129 .setkey = crc32c_vpmsum_setkey,
130 .init = crc32c_vpmsum_init,
131 .update = crc32c_vpmsum_update,
132 .final = crc32c_vpmsum_final,
133 .finup = crc32c_vpmsum_finup,
134 .digest = crc32c_vpmsum_digest,
135 .descsize = sizeof(u32),
136 .digestsize = CHKSUM_DIGEST_SIZE,
137 .base = {
138 .cra_name = "crc32c",
139 .cra_driver_name = "crc32c-vpmsum",
140 .cra_priority = 200,
141 .cra_blocksize = CHKSUM_BLOCK_SIZE,
142 .cra_ctxsize = sizeof(u32),
143 .cra_module = THIS_MODULE,
144 .cra_init = crc32c_vpmsum_cra_init,
145 }
146};
147
148static int __init crc32c_vpmsum_mod_init(void)
149{
150 if (!cpu_has_feature(CPU_FTR_ARCH_207S))
151 return -ENODEV;
152
153 return crypto_register_shash(&alg);
154}
155
156static void __exit crc32c_vpmsum_mod_fini(void)
157{
158 crypto_unregister_shash(&alg);
159}
160
161module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
162module_exit(crc32c_vpmsum_mod_fini);
163
164MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
165MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
166MODULE_LICENSE("GPL");
167MODULE_ALIAS_CRYPTO("crc32c");
168MODULE_ALIAS_CRYPTO("crc32c-vpmsum");