GNU Linux-libre 4.19.314-gnu1
[releases.git] / drivers / crypto / vmx / aes_xts.c
1 /**
2  * AES XTS routines supporting VMX In-core instructions on 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 Foundations; 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 of FITNESS FOR A PARTICUPAR 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: Leonidas S. Barbosa <leosilva@linux.vnet.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 #include <crypto/xts.h>
31 #include <crypto/skcipher.h>
32
33 #include "aesp8-ppc.h"
34
35 struct p8_aes_xts_ctx {
36         struct crypto_skcipher *fallback;
37         struct aes_key enc_key;
38         struct aes_key dec_key;
39         struct aes_key tweak_key;
40 };
41
42 static int p8_aes_xts_init(struct crypto_tfm *tfm)
43 {
44         const char *alg = crypto_tfm_alg_name(tfm);
45         struct crypto_skcipher *fallback;
46         struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
47
48         fallback = crypto_alloc_skcipher(alg, 0,
49                         CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
50         if (IS_ERR(fallback)) {
51                 printk(KERN_ERR
52                         "Failed to allocate transformation for '%s': %ld\n",
53                         alg, PTR_ERR(fallback));
54                 return PTR_ERR(fallback);
55         }
56
57         crypto_skcipher_set_flags(
58                 fallback,
59                 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm));
60         ctx->fallback = fallback;
61
62         return 0;
63 }
64
65 static void p8_aes_xts_exit(struct crypto_tfm *tfm)
66 {
67         struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
68
69         if (ctx->fallback) {
70                 crypto_free_skcipher(ctx->fallback);
71                 ctx->fallback = NULL;
72         }
73 }
74
75 static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key,
76                              unsigned int keylen)
77 {
78         int ret;
79         struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
80
81         ret = xts_check_key(tfm, key, keylen);
82         if (ret)
83                 return ret;
84
85         preempt_disable();
86         pagefault_disable();
87         enable_kernel_vsx();
88         ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key);
89         ret += aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key);
90         ret += aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key);
91         disable_kernel_vsx();
92         pagefault_enable();
93         preempt_enable();
94
95         ret += crypto_skcipher_setkey(ctx->fallback, key, keylen);
96         return ret;
97 }
98
99 static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
100                             struct scatterlist *dst,
101                             struct scatterlist *src,
102                             unsigned int nbytes, int enc)
103 {
104         int ret;
105         u8 tweak[AES_BLOCK_SIZE];
106         u8 *iv;
107         struct blkcipher_walk walk;
108         struct p8_aes_xts_ctx *ctx =
109                 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
110
111         if (in_interrupt()) {
112                 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback);
113                 skcipher_request_set_tfm(req, ctx->fallback);
114                 skcipher_request_set_callback(req, desc->flags, NULL, NULL);
115                 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
116                 ret = enc? crypto_skcipher_encrypt(req) : crypto_skcipher_decrypt(req);
117                 skcipher_request_zero(req);
118         } else {
119                 blkcipher_walk_init(&walk, dst, src, nbytes);
120
121                 ret = blkcipher_walk_virt(desc, &walk);
122
123                 preempt_disable();
124                 pagefault_disable();
125                 enable_kernel_vsx();
126
127                 iv = walk.iv;
128                 memset(tweak, 0, AES_BLOCK_SIZE);
129                 aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
130
131                 disable_kernel_vsx();
132                 pagefault_enable();
133                 preempt_enable();
134
135                 while ((nbytes = walk.nbytes)) {
136                         preempt_disable();
137                         pagefault_disable();
138                         enable_kernel_vsx();
139                         if (enc)
140                                 aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
141                                                 nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
142                         else
143                                 aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
144                                                 nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
145                         disable_kernel_vsx();
146                         pagefault_enable();
147                         preempt_enable();
148
149                         nbytes &= AES_BLOCK_SIZE - 1;
150                         ret = blkcipher_walk_done(desc, &walk, nbytes);
151                 }
152         }
153         return ret;
154 }
155
156 static int p8_aes_xts_encrypt(struct blkcipher_desc *desc,
157                               struct scatterlist *dst,
158                               struct scatterlist *src, unsigned int nbytes)
159 {
160         return p8_aes_xts_crypt(desc, dst, src, nbytes, 1);
161 }
162
163 static int p8_aes_xts_decrypt(struct blkcipher_desc *desc,
164                               struct scatterlist *dst,
165                               struct scatterlist *src, unsigned int nbytes)
166 {
167         return p8_aes_xts_crypt(desc, dst, src, nbytes, 0);
168 }
169
170 struct crypto_alg p8_aes_xts_alg = {
171         .cra_name = "xts(aes)",
172         .cra_driver_name = "p8_aes_xts",
173         .cra_module = THIS_MODULE,
174         .cra_priority = 2000,
175         .cra_type = &crypto_blkcipher_type,
176         .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
177         .cra_alignmask = 0,
178         .cra_blocksize = AES_BLOCK_SIZE,
179         .cra_ctxsize = sizeof(struct p8_aes_xts_ctx),
180         .cra_init = p8_aes_xts_init,
181         .cra_exit = p8_aes_xts_exit,
182         .cra_blkcipher = {
183                         .ivsize = AES_BLOCK_SIZE,
184                         .min_keysize = 2 * AES_MIN_KEY_SIZE,
185                         .max_keysize = 2 * AES_MAX_KEY_SIZE,
186                         .setkey  = p8_aes_xts_setkey,
187                         .encrypt = p8_aes_xts_encrypt,
188                         .decrypt = p8_aes_xts_decrypt,
189         }
190 };