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 		crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
78 		return -EINVAL;
79 	}
80 	*mctx = le32_to_cpup((__le32 *)key);
81 	return 0;
82 }
83 
84 static int crc32c_vpmsum_init(struct shash_desc *desc)
85 {
86 	u32 *mctx = crypto_shash_ctx(desc->tfm);
87 	u32 *crcp = shash_desc_ctx(desc);
88 
89 	*crcp = *mctx;
90 
91 	return 0;
92 }
93 
94 static int crc32c_vpmsum_update(struct shash_desc *desc, const u8 *data,
95 			       unsigned int len)
96 {
97 	u32 *crcp = shash_desc_ctx(desc);
98 
99 	*crcp = crc32c_vpmsum(*crcp, data, len);
100 
101 	return 0;
102 }
103 
104 static int __crc32c_vpmsum_finup(u32 *crcp, const u8 *data, unsigned int len,
105 				u8 *out)
106 {
107 	*(__le32 *)out = ~cpu_to_le32(crc32c_vpmsum(*crcp, data, len));
108 
109 	return 0;
110 }
111 
112 static int crc32c_vpmsum_finup(struct shash_desc *desc, const u8 *data,
113 			      unsigned int len, u8 *out)
114 {
115 	return __crc32c_vpmsum_finup(shash_desc_ctx(desc), data, len, out);
116 }
117 
118 static int crc32c_vpmsum_final(struct shash_desc *desc, u8 *out)
119 {
120 	u32 *crcp = shash_desc_ctx(desc);
121 
122 	*(__le32 *)out = ~cpu_to_le32p(crcp);
123 
124 	return 0;
125 }
126 
127 static int crc32c_vpmsum_digest(struct shash_desc *desc, const u8 *data,
128 			       unsigned int len, u8 *out)
129 {
130 	return __crc32c_vpmsum_finup(crypto_shash_ctx(desc->tfm), data, len,
131 				     out);
132 }
133 
134 static struct shash_alg alg = {
135 	.setkey		= crc32c_vpmsum_setkey,
136 	.init		= crc32c_vpmsum_init,
137 	.update		= crc32c_vpmsum_update,
138 	.final		= crc32c_vpmsum_final,
139 	.finup		= crc32c_vpmsum_finup,
140 	.digest		= crc32c_vpmsum_digest,
141 	.descsize	= sizeof(u32),
142 	.digestsize	= CHKSUM_DIGEST_SIZE,
143 	.base		= {
144 		.cra_name		= "crc32c",
145 		.cra_driver_name	= "crc32c-vpmsum",
146 		.cra_priority		= 200,
147 		.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
148 		.cra_blocksize		= CHKSUM_BLOCK_SIZE,
149 		.cra_ctxsize		= sizeof(u32),
150 		.cra_module		= THIS_MODULE,
151 		.cra_init		= crc32c_vpmsum_cra_init,
152 	}
153 };
154 
155 static int __init crc32c_vpmsum_mod_init(void)
156 {
157 	if (!cpu_has_feature(CPU_FTR_ARCH_207S))
158 		return -ENODEV;
159 
160 	return crypto_register_shash(&alg);
161 }
162 
163 static void __exit crc32c_vpmsum_mod_fini(void)
164 {
165 	crypto_unregister_shash(&alg);
166 }
167 
168 module_cpu_feature_match(PPC_MODULE_FEATURE_VEC_CRYPTO, crc32c_vpmsum_mod_init);
169 module_exit(crc32c_vpmsum_mod_fini);
170 
171 MODULE_AUTHOR("Anton Blanchard <anton@samba.org>");
172 MODULE_DESCRIPTION("CRC32C using vector polynomial multiply-sum instructions");
173 MODULE_LICENSE("GPL");
174 MODULE_ALIAS_CRYPTO("crc32c");
175 MODULE_ALIAS_CRYPTO("crc32c-vpmsum");
176