Linux kernel mirror (for testing)
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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#include <linux/err.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/uaccess.h>
19
20#include "aesp8-ppc.h"
21
22struct p8_aes_cbc_ctx {
23 struct crypto_skcipher *fallback;
24 struct aes_key enc_key;
25 struct aes_key dec_key;
26};
27
28static int p8_aes_cbc_init(struct crypto_skcipher *tfm)
29{
30 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
31 struct crypto_skcipher *fallback;
32
33 fallback = crypto_alloc_skcipher("cbc(aes)", 0,
34 CRYPTO_ALG_NEED_FALLBACK |
35 CRYPTO_ALG_ASYNC);
36 if (IS_ERR(fallback)) {
37 pr_err("Failed to allocate cbc(aes) fallback: %ld\n",
38 PTR_ERR(fallback));
39 return PTR_ERR(fallback);
40 }
41
42 crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
43 crypto_skcipher_reqsize(fallback));
44 ctx->fallback = fallback;
45 return 0;
46}
47
48static void p8_aes_cbc_exit(struct crypto_skcipher *tfm)
49{
50 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
51
52 crypto_free_skcipher(ctx->fallback);
53}
54
55static int p8_aes_cbc_setkey(struct crypto_skcipher *tfm, const u8 *key,
56 unsigned int keylen)
57{
58 struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
59 int ret;
60
61 preempt_disable();
62 pagefault_disable();
63 enable_kernel_vsx();
64 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
65 ret |= aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key);
66 disable_kernel_vsx();
67 pagefault_enable();
68 preempt_enable();
69
70 ret |= crypto_skcipher_setkey(ctx->fallback, key, keylen);
71
72 return ret ? -EINVAL : 0;
73}
74
75static int p8_aes_cbc_crypt(struct skcipher_request *req, int enc)
76{
77 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
78 const struct p8_aes_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
79 struct skcipher_walk walk;
80 unsigned int nbytes;
81 int ret;
82
83 if (!crypto_simd_usable()) {
84 struct skcipher_request *subreq = skcipher_request_ctx(req);
85
86 *subreq = *req;
87 skcipher_request_set_tfm(subreq, ctx->fallback);
88 return enc ? crypto_skcipher_encrypt(subreq) :
89 crypto_skcipher_decrypt(subreq);
90 }
91
92 ret = skcipher_walk_virt(&walk, req, false);
93 while ((nbytes = walk.nbytes) != 0) {
94 preempt_disable();
95 pagefault_disable();
96 enable_kernel_vsx();
97 aes_p8_cbc_encrypt(walk.src.virt.addr,
98 walk.dst.virt.addr,
99 round_down(nbytes, AES_BLOCK_SIZE),
100 enc ? &ctx->enc_key : &ctx->dec_key,
101 walk.iv, enc);
102 disable_kernel_vsx();
103 pagefault_enable();
104 preempt_enable();
105
106 ret = skcipher_walk_done(&walk, nbytes % AES_BLOCK_SIZE);
107 }
108 return ret;
109}
110
111static int p8_aes_cbc_encrypt(struct skcipher_request *req)
112{
113 return p8_aes_cbc_crypt(req, 1);
114}
115
116static int p8_aes_cbc_decrypt(struct skcipher_request *req)
117{
118 return p8_aes_cbc_crypt(req, 0);
119}
120
121struct skcipher_alg p8_aes_cbc_alg = {
122 .base.cra_name = "cbc(aes)",
123 .base.cra_driver_name = "p8_aes_cbc",
124 .base.cra_module = THIS_MODULE,
125 .base.cra_priority = 2000,
126 .base.cra_flags = CRYPTO_ALG_NEED_FALLBACK,
127 .base.cra_blocksize = AES_BLOCK_SIZE,
128 .base.cra_ctxsize = sizeof(struct p8_aes_cbc_ctx),
129 .setkey = p8_aes_cbc_setkey,
130 .encrypt = p8_aes_cbc_encrypt,
131 .decrypt = p8_aes_cbc_decrypt,
132 .init = p8_aes_cbc_init,
133 .exit = p8_aes_cbc_exit,
134 .min_keysize = AES_MIN_KEY_SIZE,
135 .max_keysize = AES_MAX_KEY_SIZE,
136 .ivsize = AES_BLOCK_SIZE,
137};