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(alg_name: "cbc(aes)", type: 0,
30 CRYPTO_ALG_NEED_FALLBACK |
31 CRYPTO_ALG_ASYNC);
32 if (IS_ERR(ptr: fallback)) {
33 pr_err("Failed to allocate cbc(aes) fallback: %ld\n",
34 PTR_ERR(fallback));
35 return PTR_ERR(ptr: fallback);
36 }
37
38 crypto_skcipher_set_reqsize(skcipher: tfm, reqsize: sizeof(struct skcipher_request) +
39 crypto_skcipher_reqsize(tfm: 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(tfm: 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(userKey: key, bits: keylen * 8, key: &ctx->enc_key);
61 ret |= aes_p8_set_decrypt_key(userKey: key, bits: keylen * 8, key: &ctx->dec_key);
62 disable_kernel_vsx();
63 pagefault_enable();
64 preempt_enable();
65
66 ret |= crypto_skcipher_setkey(tfm: 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(req: subreq, tfm: ctx->fallback);
84 return enc ? crypto_skcipher_encrypt(req: subreq) :
85 crypto_skcipher_decrypt(req: subreq);
86 }
87
88 ret = skcipher_walk_virt(walk: &walk, req, atomic: false);
89 while ((nbytes = walk.nbytes) != 0) {
90 preempt_disable();
91 pagefault_disable();
92 enable_kernel_vsx();
93 aes_p8_cbc_encrypt(in: walk.src.virt.addr,
94 out: walk.dst.virt.addr,
95 round_down(nbytes, AES_BLOCK_SIZE),
96 key: enc ? &ctx->enc_key : &ctx->dec_key,
97 iv: walk.iv, enc);
98 disable_kernel_vsx();
99 pagefault_enable();
100 preempt_enable();
101
102 ret = skcipher_walk_done(walk: &walk, err: 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, enc: 1);
110}
111
112static int p8_aes_cbc_decrypt(struct skcipher_request *req)
113{
114 return p8_aes_cbc_crypt(req, enc: 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

source code of linux/arch/powerpc/crypto/aes_cbc.c