1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AES CBC routines supporting VMX instructions on the Power 8
4 *
5 * Copyright (C) 2015 International Business Machines Inc.
6 *
7 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
8 */
9
10 #include <asm/simd.h>
11 #include <asm/switch_to.h>
12 #include <crypto/aes.h>
13 #include <crypto/internal/simd.h>
14 #include <crypto/internal/skcipher.h>
15
16 #include "aesp8-ppc.h"
17
18 struct p8_aes_cbc_ctx {
19 struct crypto_skcipher *fallback;
20 struct aes_key enc_key;
21 struct aes_key dec_key;
22 };
23
24 static int p8_aes_cbc_init(struct crypto_skcipher *tfm)
25 {
26 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
27 struct crypto_skcipher *fallback;
28
29 fallback = crypto_alloc_skcipher("cbc(aes)", 0,
30 CRYPTO_ALG_NEED_FALLBACK |
31 CRYPTO_ALG_ASYNC);
32 if (IS_ERR(fallback)) {
33 pr_err("Failed to allocate cbc(aes) fallback: %ld\n",
34 PTR_ERR(fallback));
35 return PTR_ERR(fallback);
36 }
37
38 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
39 crypto_skcipher_reqsize(fallback));
40 ctx->fallback = fallback;
41 return 0;
42 }
43
44 static void p8_aes_cbc_exit(struct crypto_skcipher *tfm)
45 {
46 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
47
48 crypto_free_skcipher(ctx->fallback);
49 }
50
51 static int p8_aes_cbc_setkey(struct crypto_skcipher *tfm, const u8 *key,
52 unsigned int keylen)
53 {
54 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
55 int ret;
56
57 preempt_disable();
58 pagefault_disable();
59 enable_kernel_vsx();
60 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
61 ret |= aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key);
62 disable_kernel_vsx();
63 pagefault_enable();
64 preempt_enable();
65
66 ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);
67
68 return ret ? -EINVAL : 0;
69 }
70
71 static int p8_aes_cbc_crypt(struct skcipher_request *req, int enc)
72 {
73 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
74 const struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
75 struct skcipher_walk walk;
76 unsigned int nbytes;
77 int ret;
78
79 if (!crypto_simd_usable()) {
80 struct skcipher_request *subreq = skcipher_request_ctx(req);
81
82 *subreq = *req;
83 skcipher_request_set_tfm(subreq, ctx->fallback);
84 return enc ? crypto_skcipher_encrypt(subreq) :
85 crypto_skcipher_decrypt(subreq);
86 }
87
88 ret = skcipher_walk_virt(&walk, req, false);
89 while ((nbytes = walk.nbytes) != 0) {
90 preempt_disable();
91 pagefault_disable();
92 enable_kernel_vsx();
93 aes_p8_cbc_encrypt(walk.src.virt.addr,
94 walk.dst.virt.addr,
95 round_down(nbytes, AES_BLOCK_SIZE),
96 enc ? &ctx->enc_key : &ctx->dec_key,
97 walk.iv, enc);
98 disable_kernel_vsx();
99 pagefault_enable();
100 preempt_enable();
101
102 ret = skcipher_walk_done(&walk, nbytes % AES_BLOCK_SIZE);
103 }
104 return ret;
105 }
106
107 static int p8_aes_cbc_encrypt(struct skcipher_request *req)
108 {
109 return p8_aes_cbc_crypt(req, 1);
110 }
111
112 static int p8_aes_cbc_decrypt(struct skcipher_request *req)
113 {
114 return p8_aes_cbc_crypt(req, 0);
115 }
116
117 struct skcipher_alg p8_aes_cbc_alg = {
118 .base.cra_name = "cbc(aes)",
119 .base.cra_driver_name = "p8_aes_cbc",
120 .base.cra_module = THIS_MODULE,
121 .base.cra_priority = 2000,
122 .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
123 .base.cra_blocksize = AES_BLOCK_SIZE,
124 .base.cra_ctxsize = sizeof(struct p8_aes_cbc_ctx),
125 .setkey = p8_aes_cbc_setkey,
126 .encrypt = p8_aes_cbc_encrypt,
127 .decrypt = p8_aes_cbc_decrypt,
128 .init = p8_aes_cbc_init,
129 .exit = p8_aes_cbc_exit,
130 .min_keysize = AES_MIN_KEY_SIZE,
131 .max_keysize = AES_MAX_KEY_SIZE,
132 .ivsize = AES_BLOCK_SIZE,
133 };
134
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