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
18struct p8_aes_cbc_ctx {
19	struct crypto_skcipher *fallback;
20	struct aes_key enc_key;
21	struct aes_key dec_key;
22};
23
24static 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
44static 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
51static 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
71static 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
107static int p8_aes_cbc_encrypt(struct skcipher_request *req)
108{
109	return p8_aes_cbc_crypt(req, 1);
110}
111
112static int p8_aes_cbc_decrypt(struct skcipher_request *req)
113{
114	return p8_aes_cbc_crypt(req, 0);
115}
116
117struct 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