1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
// SPDX-License-Identifier: GPL-2.0
/*
* s390 ChaCha stream cipher.
*
* Copyright IBM Corp. 2021
*/
#define KMSG_COMPONENT "chacha_s390"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <crypto/internal/chacha.h>
#include <crypto/internal/skcipher.h>
#include <crypto/algapi.h>
#include <linux/cpufeature.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sizes.h>
#include <asm/fpu/api.h>
#include "chacha-s390.h"
static void chacha20_crypt_s390(u32 *state, u8 *dst, const u8 *src,
unsigned int nbytes, const u32 *key,
u32 *counter)
{
struct kernel_fpu vxstate;
kernel_fpu_begin(&vxstate, KERNEL_VXR);
chacha20_vx(dst, src, nbytes, key, counter);
kernel_fpu_end(&vxstate, KERNEL_VXR);
*counter += round_up(nbytes, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
}
static int chacha20_s390(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
u32 state[CHACHA_STATE_WORDS] __aligned(16);
struct skcipher_walk walk;
unsigned int nbytes;
int rc;
rc = skcipher_walk_virt(&walk, req, false);
chacha_init_generic(state, ctx->key, req->iv);
while (walk.nbytes > 0) {
nbytes = walk.nbytes;
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);
if (nbytes <= CHACHA_BLOCK_SIZE) {
chacha_crypt_generic(state, walk.dst.virt.addr,
walk.src.virt.addr, nbytes,
ctx->nrounds);
} else {
chacha20_crypt_s390(state, walk.dst.virt.addr,
walk.src.virt.addr, nbytes,
&state[4], &state[12]);
}
rc = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return rc;
}
static struct skcipher_alg chacha_algs[] = {
{
.base.cra_name = "chacha20",
.base.cra_driver_name = "chacha20-s390",
.base.cra_priority = 900,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = CHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = chacha20_setkey,
.encrypt = chacha20_s390,
.decrypt = chacha20_s390,
}
};
static int __init chacha_mod_init(void)
{
return crypto_register_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs));
}
static void __exit chacha_mod_fini(void)
{
crypto_unregister_skciphers(chacha_algs, ARRAY_SIZE(chacha_algs));
}
module_cpu_feature_match(VXRS, chacha_mod_init);
module_exit(chacha_mod_fini);
MODULE_DESCRIPTION("ChaCha20 stream cipher");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("chacha20");
|
