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Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -02001/**
2 * AES CBC routines supporting VMX instructions on the Power 8
3 *
4 * Copyright (C) 2015 International Business Machines Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 only.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 *
19 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
20 */
21
22#include <linux/types.h>
23#include <linux/err.h>
24#include <linux/crypto.h>
25#include <linux/delay.h>
26#include <linux/hardirq.h>
27#include <asm/switch_to.h>
28#include <crypto/aes.h>
29#include <crypto/scatterwalk.h>
30
31#include "aesp8-ppc.h"
32
33struct p8_aes_cbc_ctx {
Herbert Xu4beb1062015-06-15 16:55:46 +080034 struct crypto_blkcipher *fallback;
35 struct aes_key enc_key;
36 struct aes_key dec_key;
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020037};
38
39static int p8_aes_cbc_init(struct crypto_tfm *tfm)
40{
Herbert Xu4beb1062015-06-15 16:55:46 +080041 const char *alg;
42 struct crypto_blkcipher *fallback;
43 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020044
Herbert Xu4beb1062015-06-15 16:55:46 +080045 if (!(alg = crypto_tfm_alg_name(tfm))) {
46 printk(KERN_ERR "Failed to get algorithm name.\n");
47 return -ENOENT;
48 }
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020049
Herbert Xu4beb1062015-06-15 16:55:46 +080050 fallback =
51 crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
52 if (IS_ERR(fallback)) {
53 printk(KERN_ERR
54 "Failed to allocate transformation for '%s': %ld\n",
55 alg, PTR_ERR(fallback));
56 return PTR_ERR(fallback);
57 }
58 printk(KERN_INFO "Using '%s' as fallback implementation.\n",
59 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020060
Herbert Xu4beb1062015-06-15 16:55:46 +080061 crypto_blkcipher_set_flags(
62 fallback,
63 crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
64 ctx->fallback = fallback;
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020065
Herbert Xu4beb1062015-06-15 16:55:46 +080066 return 0;
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020067}
68
69static void p8_aes_cbc_exit(struct crypto_tfm *tfm)
70{
Herbert Xu4beb1062015-06-15 16:55:46 +080071 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020072
Herbert Xu4beb1062015-06-15 16:55:46 +080073 if (ctx->fallback) {
74 crypto_free_blkcipher(ctx->fallback);
75 ctx->fallback = NULL;
76 }
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020077}
78
79static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const u8 *key,
Herbert Xu4beb1062015-06-15 16:55:46 +080080 unsigned int keylen)
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020081{
Herbert Xu4beb1062015-06-15 16:55:46 +080082 int ret;
83 struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020084
Linus Torvalds44d21c32015-06-22 21:04:48 -070085 preempt_disable();
Herbert Xu4beb1062015-06-15 16:55:46 +080086 pagefault_disable();
Leonidas Da Silva Barbosa2d6f0602015-07-13 13:51:39 -030087 enable_kernel_vsx();
Herbert Xu4beb1062015-06-15 16:55:46 +080088 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
89 ret += aes_p8_set_decrypt_key(key, keylen * 8, &ctx->dec_key);
Anton Blancharddc4fbba2015-10-29 11:44:05 +110090 disable_kernel_vsx();
Herbert Xu4beb1062015-06-15 16:55:46 +080091 pagefault_enable();
Linus Torvalds44d21c32015-06-22 21:04:48 -070092 preempt_enable();
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020093
Herbert Xu4beb1062015-06-15 16:55:46 +080094 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
95 return ret;
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -020096}
97
98static int p8_aes_cbc_encrypt(struct blkcipher_desc *desc,
Herbert Xu4beb1062015-06-15 16:55:46 +080099 struct scatterlist *dst,
100 struct scatterlist *src, unsigned int nbytes)
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200101{
Herbert Xu4beb1062015-06-15 16:55:46 +0800102 int ret;
103 struct blkcipher_walk walk;
104 struct p8_aes_cbc_ctx *ctx =
105 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
106 struct blkcipher_desc fallback_desc = {
107 .tfm = ctx->fallback,
108 .info = desc->info,
109 .flags = desc->flags
110 };
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200111
Herbert Xu4beb1062015-06-15 16:55:46 +0800112 if (in_interrupt()) {
113 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
114 nbytes);
115 } else {
Linus Torvalds44d21c32015-06-22 21:04:48 -0700116 preempt_disable();
Herbert Xu4beb1062015-06-15 16:55:46 +0800117 pagefault_disable();
Leonidas Da Silva Barbosa2d6f0602015-07-13 13:51:39 -0300118 enable_kernel_vsx();
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200119
Herbert Xu4beb1062015-06-15 16:55:46 +0800120 blkcipher_walk_init(&walk, dst, src, nbytes);
121 ret = blkcipher_walk_virt(desc, &walk);
122 while ((nbytes = walk.nbytes)) {
123 aes_p8_cbc_encrypt(walk.src.virt.addr,
124 walk.dst.virt.addr,
125 nbytes & AES_BLOCK_MASK,
126 &ctx->enc_key, walk.iv, 1);
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200127 nbytes &= AES_BLOCK_SIZE - 1;
128 ret = blkcipher_walk_done(desc, &walk, nbytes);
129 }
130
Anton Blancharddc4fbba2015-10-29 11:44:05 +1100131 disable_kernel_vsx();
Herbert Xu4beb1062015-06-15 16:55:46 +0800132 pagefault_enable();
Linus Torvalds44d21c32015-06-22 21:04:48 -0700133 preempt_enable();
Herbert Xu4beb1062015-06-15 16:55:46 +0800134 }
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200135
Herbert Xu4beb1062015-06-15 16:55:46 +0800136 return ret;
137}
138
139static int p8_aes_cbc_decrypt(struct blkcipher_desc *desc,
140 struct scatterlist *dst,
141 struct scatterlist *src, unsigned int nbytes)
142{
143 int ret;
144 struct blkcipher_walk walk;
145 struct p8_aes_cbc_ctx *ctx =
146 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
147 struct blkcipher_desc fallback_desc = {
148 .tfm = ctx->fallback,
149 .info = desc->info,
150 .flags = desc->flags
151 };
152
153 if (in_interrupt()) {
154 ret = crypto_blkcipher_decrypt(&fallback_desc, dst, src,
155 nbytes);
156 } else {
Linus Torvalds44d21c32015-06-22 21:04:48 -0700157 preempt_disable();
Herbert Xu4beb1062015-06-15 16:55:46 +0800158 pagefault_disable();
Leonidas Da Silva Barbosa2d6f0602015-07-13 13:51:39 -0300159 enable_kernel_vsx();
Herbert Xu4beb1062015-06-15 16:55:46 +0800160
161 blkcipher_walk_init(&walk, dst, src, nbytes);
162 ret = blkcipher_walk_virt(desc, &walk);
163 while ((nbytes = walk.nbytes)) {
164 aes_p8_cbc_encrypt(walk.src.virt.addr,
165 walk.dst.virt.addr,
166 nbytes & AES_BLOCK_MASK,
167 &ctx->dec_key, walk.iv, 0);
168 nbytes &= AES_BLOCK_SIZE - 1;
169 ret = blkcipher_walk_done(desc, &walk, nbytes);
170 }
171
Anton Blancharddc4fbba2015-10-29 11:44:05 +1100172 disable_kernel_vsx();
Herbert Xu4beb1062015-06-15 16:55:46 +0800173 pagefault_enable();
Linus Torvalds44d21c32015-06-22 21:04:48 -0700174 preempt_enable();
Herbert Xu4beb1062015-06-15 16:55:46 +0800175 }
176
177 return ret;
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200178}
179
180
181struct crypto_alg p8_aes_cbc_alg = {
Herbert Xu4beb1062015-06-15 16:55:46 +0800182 .cra_name = "cbc(aes)",
183 .cra_driver_name = "p8_aes_cbc",
184 .cra_module = THIS_MODULE,
185 .cra_priority = 1000,
186 .cra_type = &crypto_blkcipher_type,
187 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
188 .cra_alignmask = 0,
189 .cra_blocksize = AES_BLOCK_SIZE,
190 .cra_ctxsize = sizeof(struct p8_aes_cbc_ctx),
191 .cra_init = p8_aes_cbc_init,
192 .cra_exit = p8_aes_cbc_exit,
193 .cra_blkcipher = {
Leonidas Da Silva Barbosa0d3d0542015-11-30 16:19:03 -0200194 .ivsize = AES_BLOCK_SIZE,
Herbert Xu4beb1062015-06-15 16:55:46 +0800195 .min_keysize = AES_MIN_KEY_SIZE,
196 .max_keysize = AES_MAX_KEY_SIZE,
197 .setkey = p8_aes_cbc_setkey,
198 .encrypt = p8_aes_cbc_encrypt,
199 .decrypt = p8_aes_cbc_decrypt,
200 },
Marcelo H. Cerri8c755ac2015-02-06 14:57:53 -0200201};