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10#include <crypto/internal/hash.h>
11#include <linux/module.h>
12#include <linux/cpufeature.h>
13#include <asm/cpacf.h>
14
15#define GHASH_BLOCK_SIZE 16
16#define GHASH_DIGEST_SIZE 16
17
18struct ghash_ctx {
19 u8 key[GHASH_BLOCK_SIZE];
20};
21
22struct ghash_desc_ctx {
23 u8 icv[GHASH_BLOCK_SIZE];
24 u8 key[GHASH_BLOCK_SIZE];
25 u8 buffer[GHASH_BLOCK_SIZE];
26 u32 bytes;
27};
28
29static int ghash_init(struct shash_desc *desc)
30{
31 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
32 struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
33
34 memset(dctx, 0, sizeof(*dctx));
35 memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
36
37 return 0;
38}
39
40static int ghash_setkey(struct crypto_shash *tfm,
41 const u8 *key, unsigned int keylen)
42{
43 struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
44
45 if (keylen != GHASH_BLOCK_SIZE) {
46 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
47 return -EINVAL;
48 }
49
50 memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
51
52 return 0;
53}
54
55static int ghash_update(struct shash_desc *desc,
56 const u8 *src, unsigned int srclen)
57{
58 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
59 unsigned int n;
60 u8 *buf = dctx->buffer;
61
62 if (dctx->bytes) {
63 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
64
65 n = min(srclen, dctx->bytes);
66 dctx->bytes -= n;
67 srclen -= n;
68
69 memcpy(pos, src, n);
70 src += n;
71
72 if (!dctx->bytes) {
73 cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
74 GHASH_BLOCK_SIZE);
75 }
76 }
77
78 n = srclen & ~(GHASH_BLOCK_SIZE - 1);
79 if (n) {
80 cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
81 src += n;
82 srclen -= n;
83 }
84
85 if (srclen) {
86 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
87 memcpy(buf, src, srclen);
88 }
89
90 return 0;
91}
92
93static int ghash_flush(struct ghash_desc_ctx *dctx)
94{
95 u8 *buf = dctx->buffer;
96
97 if (dctx->bytes) {
98 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
99
100 memset(pos, 0, dctx->bytes);
101 cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
102 dctx->bytes = 0;
103 }
104
105 return 0;
106}
107
108static int ghash_final(struct shash_desc *desc, u8 *dst)
109{
110 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
111 int ret;
112
113 ret = ghash_flush(dctx);
114 if (!ret)
115 memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
116 return ret;
117}
118
119static struct shash_alg ghash_alg = {
120 .digestsize = GHASH_DIGEST_SIZE,
121 .init = ghash_init,
122 .update = ghash_update,
123 .final = ghash_final,
124 .setkey = ghash_setkey,
125 .descsize = sizeof(struct ghash_desc_ctx),
126 .base = {
127 .cra_name = "ghash",
128 .cra_driver_name = "ghash-s390",
129 .cra_priority = 300,
130 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
131 .cra_blocksize = GHASH_BLOCK_SIZE,
132 .cra_ctxsize = sizeof(struct ghash_ctx),
133 .cra_module = THIS_MODULE,
134 },
135};
136
137static int __init ghash_mod_init(void)
138{
139 if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
140 return -EOPNOTSUPP;
141
142 return crypto_register_shash(&ghash_alg);
143}
144
145static void __exit ghash_mod_exit(void)
146{
147 crypto_unregister_shash(&ghash_alg);
148}
149
150module_cpu_feature_match(MSA, ghash_mod_init);
151module_exit(ghash_mod_exit);
152
153MODULE_ALIAS_CRYPTO("ghash");
154
155MODULE_LICENSE("GPL");
156MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");
157
