1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/crc32.h>
3 #include <crypto/internal/hash.h>
4 #include <crypto/internal/simd.h>
5 #include <linux/init.h>
6 #include <linux/module.h>
7 #include <linux/string.h>
8 #include <linux/kernel.h>
9 #include <linux/cpufeature.h>
10 #include <asm/simd.h>
11 #include <asm/switch_to.h>
12
13 #define CHKSUM_BLOCK_SIZE 1
14 #define CHKSUM_DIGEST_SIZE 4
15
16 #define VMX_ALIGN 16
17 #define VMX_ALIGN_MASK (VMX_ALIGN-1)
18
19 #define VECTOR_BREAKPOINT 512
20
21 u32 __crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len);
22
23 static u32 crc32c_vpmsum(u32 crc, unsigned char const *p, size_t len)
24 {
25 unsigned int prealign;
26 unsigned int tail;
27
28 if (len < (VECTOR_BREAKPOINT + VMX_ALIGN) || !crypto_simd_usable())
29 return __crc32c_le(crc, p, len);
30
31 if ((unsigned long)p & VMX_ALIGN_MASK) {
32 prealign = VMX_ALIGN - ((unsigned long)p & VMX_ALIGN_MASK);
33 crc = __crc32c_le(crc, p, prealign);
34 len -= prealign;
35 p += prealign;
36 }
37
38 if (len & ~VMX_ALIGN_MASK) {
39 preempt_disable();
40 pagefault_disable();
41 enable_kernel_altivec();
42 crc = __crc32c_vpmsum(crc, p, len & ~VMX_ALIGN_MASK);
43 disable_kernel_altivec();
44 pagefault_enable();
45 preempt_enable();
46 }
47
48 tail = len & VMX_ALIGN_MASK;
49 if (tail) {
50 p += len & ~VMX_ALIGN_MASK;
51 crc = __crc32c_le(crc, p, tail);
52 }
53
54 return crc;
55 }
56
57 static int crc32c_vpmsum_cra_init(struct crypto_tfm *tfm)
58 {
59 u32 *key = crypto_tfm_ctx(tfm);
60
61 *key = ~0;
62
63 return 0;
64 }
65
66 /*
67 * Setting the seed allows arbitrary accumulators and flexible XOR policy
68 * If your algorithm starts with ~0, then XOR with ~0 before you set
69 * the seed.
70 */
71 static int crc32c_vpmsum_setkey(struct crypto_shash *hash, const u8 *key,
72 unsigned int keylen)
73 {
74 u32 *mctx = crypto_shash_ctx(hash);
75
76 if (keylen != sizeof(u32))
77 return -EINVAL;
78 *mctx = le32_to_cpup((__le32 *)key);
79 return 0;
80 }
81
82 static int crc32c_vpmsum_init(struct shash_desc *desc)
83 {
84 u32 *mctx = crypto_shash_ctx(desc->tfm);
85 u32 *crcp = shash_desc_ctx(desc);
86
87 *crcp = *mctx;
88
89 return 0;
90 }
91
92 static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
93 unsigned int len)
94 {
95 u32 *crcp = shash_desc_ctx(desc);
96
97 *crcp = crc32c_vpmsum(*crcp, data, len);
98
99 return 0;
100 }
101
102 static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
103 u8 *out)
104 {
105 *(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
106
107 return 0;
108 }
109
110 static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
111 unsigned int len, u8 *out)
112 {
113 return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
114 }
115
116 static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
117 {
118 u32 *crcp = shash_desc_ctx(desc);
119
120 *(__le32 *)out = ~cpu_to_le32p(crcp);
121
122 return 0;
123 }
124
125 static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
126 unsigned int len, u8 *out)
127 {
128 return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
129 out);
130 }
131
132 static struct shash_alg alg = {
133 .setkey = crc32c_vpmsum_setkey,
134 .init = crc32c_vpmsum_init,
135 .update = crc32c_vpmsum_update,
136 .final = crc32c_vpmsum_final,
137 .finup = crc32c_vpmsum_finup,
138 .digest = crc32c_vpmsum_digest,
139 .descsize = sizeof(u32),
140 .digestsize = CHKSUM_DIGEST_SIZE,
141 .base = {
142 .cra_name = "crc32c",
143 .cra_driver_name = "crc32c-vpmsum",
144 .cra_priority = 200,
145 .cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
146 .cra_blocksize = CHKSUM_BLOCK_SIZE,
147 .cra_ctxsize = sizeof(u32),
148 .cra_module = THIS_MODULE,
149 .cra_init = crc32c_vpmsum_cra_init,
150 }
151 };
152
153 static int __init crc32c_vpmsum_mod_init(void)
154 {
155 if (!cpu_has_feature(CPU_FTR_ARCH_207S))
156 return -ENODEV;
157
158 return crypto_register_shash(&alg);
159 }
160
161 static void __exit crc32c_vpmsum_mod_fini(void)
162 {
163 crypto_unregister_shash(&alg);
164 }
165
166 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
167 module_exit(crc32c_vpmsum_mod_fini);
168
169 MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
170 MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
171 MODULE_LICENSE("GPL");
172 MODULE_ALIAS_CRYPTO("crc32c");
173 MODULE_ALIAS_CRYPTO("crc32c-vpmsum");
174
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