1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * s390 ChaCha stream cipher.
4 *
5 * Copyright IBM Corp. 2021
6 */
7
8 #define KMSG_COMPONENT "chacha_s390"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10
11 #include <crypto/internal/chacha.h>
12 #include <crypto/internal/skcipher.h>
13 #include <crypto/algapi.h>
14 #include <linux/cpufeature.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/sizes.h>
18 #include <asm/fpu.h>
19 #include "chacha-s390.h"
20
21 static void chacha20_crypt_s390(u32 *state, u8
22 unsigned int n
23 u32 *counter)
24 {
25 DECLARE_KERNEL_FPU_ONSTACK32(vxstate);
26
27 kernel_fpu_begin(&vxstate, KERNEL_VXR)
28 chacha20_vx(dst, src, nbytes, key, cou
29 kernel_fpu_end(&vxstate, KERNEL_VXR);
30
31 *counter += round_up(nbytes, CHACHA_BL
32 }
33
34 static int chacha20_s390(struct skcipher_reque
35 {
36 struct crypto_skcipher *tfm = crypto_s
37 struct chacha_ctx *ctx = crypto_skciph
38 u32 state[CHACHA_STATE_WORDS] __aligne
39 struct skcipher_walk walk;
40 unsigned int nbytes;
41 int rc;
42
43 rc = skcipher_walk_virt(&walk, req, fa
44 chacha_init_generic(state, ctx->key, r
45
46 while (walk.nbytes > 0) {
47 nbytes = walk.nbytes;
48 if (nbytes < walk.total)
49 nbytes = round_down(nb
50
51 if (nbytes <= CHACHA_BLOCK_SIZ
52 chacha_crypt_generic(s
53 w
54 c
55 } else {
56 chacha20_crypt_s390(st
57 wa
58 &s
59 }
60 rc = skcipher_walk_done(&walk,
61 }
62 return rc;
63 }
64
65 void hchacha_block_arch(const u32 *state, u32
66 {
67 /* TODO: implement hchacha_block_arch(
68 hchacha_block_generic(state, stream, n
69 }
70 EXPORT_SYMBOL(hchacha_block_arch);
71
72 void chacha_init_arch(u32 *state, const u32 *k
73 {
74 chacha_init_generic(state, key, iv);
75 }
76 EXPORT_SYMBOL(chacha_init_arch);
77
78 void chacha_crypt_arch(u32 *state, u8 *dst, co
79 unsigned int bytes, int
80 {
81 /* s390 chacha20 implementation has 20
82 * it cannot handle a block of data or
83 * it can handle data of arbitrary siz
84 */
85 if (bytes <= CHACHA_BLOCK_SIZE || nrou
86 chacha_crypt_generic(state, ds
87 else
88 chacha20_crypt_s390(state, dst
89 &state[4],
90 }
91 EXPORT_SYMBOL(chacha_crypt_arch);
92
93 static struct skcipher_alg chacha_algs[] = {
94 {
95 .base.cra_name = "cha
96 .base.cra_driver_name = "cha
97 .base.cra_priority = 900,
98 .base.cra_blocksize = 1,
99 .base.cra_ctxsize = size
100 .base.cra_module = THIS
101
102 .min_keysize = CHAC
103 .max_keysize = CHAC
104 .ivsize = CHAC
105 .chunksize = CHAC
106 .setkey = chac
107 .encrypt = chac
108 .decrypt = chac
109 }
110 };
111
112 static int __init chacha_mod_init(void)
113 {
114 return IS_REACHABLE(CONFIG_CRYPTO_SKCI
115 crypto_register_skciphers(chac
116 }
117
118 static void __exit chacha_mod_fini(void)
119 {
120 if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHE
121 crypto_unregister_skciphers(ch
122 }
123
124 module_cpu_feature_match(S390_CPU_FEATURE_VXRS
125 module_exit(chacha_mod_fini);
126
127 MODULE_DESCRIPTION("ChaCha20 stream cipher");
128 MODULE_LICENSE("GPL v2");
129
130 MODULE_ALIAS_CRYPTO("chacha20");
131
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