2 * AES XTS routines supporting VMX In-core instructions on Power 8
4 * Copyright (C) 2015 International Business Machines Inc.
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.
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.
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.
19 * Author: Leonidas S. Barbosa <leosilva@linux.vnet.ibm.com>
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>
33 #include "aesp8-ppc.h"
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;
42 static int p8_aes_xts_init(struct crypto_tfm *tfm)
45 struct crypto_skcipher *fallback;
46 struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
48 if (!(alg = crypto_tfm_alg_name(tfm))) {
49 printk(KERN_ERR "Failed to get algorithm name.\n");
53 fallback = crypto_alloc_skcipher(alg, 0,
54 CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
55 if (IS_ERR(fallback)) {
57 "Failed to allocate transformation for '%s': %ld\n",
58 alg, PTR_ERR(fallback));
59 return PTR_ERR(fallback);
61 printk(KERN_INFO "Using '%s' as fallback implementation.\n",
62 crypto_skcipher_driver_name(fallback));
64 crypto_skcipher_set_flags(
66 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm));
67 ctx->fallback = fallback;
72 static void p8_aes_xts_exit(struct crypto_tfm *tfm)
74 struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
77 crypto_free_skcipher(ctx->fallback);
82 static int p8_aes_xts_setkey(struct crypto_tfm *tfm, const u8 *key,
86 struct p8_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
88 ret = xts_check_key(tfm, key, keylen);
95 ret = aes_p8_set_encrypt_key(key + keylen/2, (keylen/2) * 8, &ctx->tweak_key);
96 ret += aes_p8_set_encrypt_key(key, (keylen/2) * 8, &ctx->enc_key);
97 ret += aes_p8_set_decrypt_key(key, (keylen/2) * 8, &ctx->dec_key);
102 ret += crypto_skcipher_setkey(ctx->fallback, key, keylen);
106 static int p8_aes_xts_crypt(struct blkcipher_desc *desc,
107 struct scatterlist *dst,
108 struct scatterlist *src,
109 unsigned int nbytes, int enc)
112 u8 tweak[AES_BLOCK_SIZE];
114 struct blkcipher_walk walk;
115 struct p8_aes_xts_ctx *ctx =
116 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
118 if (in_interrupt()) {
119 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback);
120 skcipher_request_set_tfm(req, ctx->fallback);
121 skcipher_request_set_callback(req, desc->flags, NULL, NULL);
122 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
123 ret = enc? crypto_skcipher_encrypt(req) : crypto_skcipher_decrypt(req);
124 skcipher_request_zero(req);
130 blkcipher_walk_init(&walk, dst, src, nbytes);
132 ret = blkcipher_walk_virt(desc, &walk);
134 memset(tweak, 0, AES_BLOCK_SIZE);
135 aes_p8_encrypt(iv, tweak, &ctx->tweak_key);
137 while ((nbytes = walk.nbytes)) {
139 aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
140 nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak);
142 aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
143 nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak);
145 nbytes &= AES_BLOCK_SIZE - 1;
146 ret = blkcipher_walk_done(desc, &walk, nbytes);
149 disable_kernel_vsx();
156 static int p8_aes_xts_encrypt(struct blkcipher_desc *desc,
157 struct scatterlist *dst,
158 struct scatterlist *src, unsigned int nbytes)
160 return p8_aes_xts_crypt(desc, dst, src, nbytes, 1);
163 static int p8_aes_xts_decrypt(struct blkcipher_desc *desc,
164 struct scatterlist *dst,
165 struct scatterlist *src, unsigned int nbytes)
167 return p8_aes_xts_crypt(desc, dst, src, nbytes, 0);
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,
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,
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,