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4f7f60d3 MC |
1 | /** |
2 | * AES CTR 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 | #include "aesp8-ppc.h" | |
31 | ||
32 | struct p8_aes_ctr_ctx { | |
33 | struct crypto_blkcipher *fallback; | |
34 | struct aes_key enc_key; | |
35 | }; | |
36 | ||
37 | static int p8_aes_ctr_init(struct crypto_tfm *tfm) | |
38 | { | |
39 | const char *alg; | |
40 | struct crypto_blkcipher *fallback; | |
41 | struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); | |
42 | ||
43 | if (!(alg = crypto_tfm_alg_name(tfm))) { | |
44 | printk(KERN_ERR "Failed to get algorithm name.\n"); | |
45 | return -ENOENT; | |
46 | } | |
47 | ||
48 | fallback = crypto_alloc_blkcipher(alg, 0 ,CRYPTO_ALG_NEED_FALLBACK); | |
49 | if (IS_ERR(fallback)) { | |
50 | printk(KERN_ERR "Failed to allocate transformation for '%s': %ld\n", | |
51 | alg, PTR_ERR(fallback)); | |
52 | return PTR_ERR(fallback); | |
53 | } | |
54 | printk(KERN_INFO "Using '%s' as fallback implementation.\n", | |
55 | crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback)); | |
56 | ||
57 | crypto_blkcipher_set_flags(fallback, | |
58 | crypto_blkcipher_get_flags((struct crypto_blkcipher *) tfm)); | |
59 | ctx->fallback = fallback; | |
60 | ||
61 | return 0; | |
62 | } | |
63 | ||
64 | static void p8_aes_ctr_exit(struct crypto_tfm *tfm) | |
65 | { | |
66 | struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); | |
67 | ||
68 | if (ctx->fallback) { | |
69 | crypto_free_blkcipher(ctx->fallback); | |
70 | ctx->fallback = NULL; | |
71 | } | |
72 | } | |
73 | ||
74 | static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key, | |
75 | unsigned int keylen) | |
76 | { | |
77 | int ret; | |
78 | struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); | |
79 | ||
80 | pagefault_disable(); | |
81 | enable_kernel_altivec(); | |
82 | ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); | |
83 | pagefault_enable(); | |
84 | ||
85 | ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen); | |
86 | return ret; | |
87 | } | |
88 | ||
89 | static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx, | |
90 | struct blkcipher_walk *walk) | |
91 | { | |
92 | u8 *ctrblk = walk->iv; | |
93 | u8 keystream[AES_BLOCK_SIZE]; | |
94 | u8 *src = walk->src.virt.addr; | |
95 | u8 *dst = walk->dst.virt.addr; | |
96 | unsigned int nbytes = walk->nbytes; | |
97 | ||
98 | pagefault_disable(); | |
99 | enable_kernel_altivec(); | |
100 | aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); | |
101 | pagefault_enable(); | |
102 | ||
103 | crypto_xor(keystream, src, nbytes); | |
104 | memcpy(dst, keystream, nbytes); | |
105 | crypto_inc(ctrblk, AES_BLOCK_SIZE); | |
106 | } | |
107 | ||
108 | static int p8_aes_ctr_crypt(struct blkcipher_desc *desc, | |
109 | struct scatterlist *dst, struct scatterlist *src, | |
110 | unsigned int nbytes) | |
111 | { | |
112 | int ret; | |
113 | struct blkcipher_walk walk; | |
114 | struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx( | |
115 | crypto_blkcipher_tfm(desc->tfm)); | |
116 | struct blkcipher_desc fallback_desc = { | |
117 | .tfm = ctx->fallback, | |
118 | .info = desc->info, | |
119 | .flags = desc->flags | |
120 | }; | |
121 | ||
122 | if (in_interrupt()) { | |
123 | ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src, nbytes); | |
124 | } else { | |
125 | blkcipher_walk_init(&walk, dst, src, nbytes); | |
126 | ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE); | |
127 | while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) { | |
128 | pagefault_disable(); | |
129 | enable_kernel_altivec(); | |
130 | aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr, walk.dst.virt.addr, | |
131 | (nbytes & AES_BLOCK_MASK)/AES_BLOCK_SIZE, &ctx->enc_key, walk.iv); | |
132 | pagefault_enable(); | |
133 | ||
134 | crypto_inc(walk.iv, AES_BLOCK_SIZE); | |
135 | nbytes &= AES_BLOCK_SIZE - 1; | |
136 | ret = blkcipher_walk_done(desc, &walk, nbytes); | |
137 | } | |
138 | if (walk.nbytes) { | |
139 | p8_aes_ctr_final(ctx, &walk); | |
140 | ret = blkcipher_walk_done(desc, &walk, 0); | |
141 | } | |
142 | } | |
143 | ||
144 | return ret; | |
145 | } | |
146 | ||
147 | struct crypto_alg p8_aes_ctr_alg = { | |
148 | .cra_name = "ctr(aes)", | |
149 | .cra_driver_name = "p8_aes_ctr", | |
150 | .cra_module = THIS_MODULE, | |
151 | .cra_priority = 1000, | |
152 | .cra_type = &crypto_blkcipher_type, | |
153 | .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK, | |
154 | .cra_alignmask = 0, | |
155 | .cra_blocksize = 1, | |
156 | .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx), | |
157 | .cra_init = p8_aes_ctr_init, | |
158 | .cra_exit = p8_aes_ctr_exit, | |
159 | .cra_blkcipher = { | |
160 | .ivsize = 0, | |
161 | .min_keysize = AES_MIN_KEY_SIZE, | |
162 | .max_keysize = AES_MAX_KEY_SIZE, | |
163 | .setkey = p8_aes_ctr_setkey, | |
164 | .encrypt = p8_aes_ctr_crypt, | |
165 | .decrypt = p8_aes_ctr_crypt, | |
166 | }, | |
167 | }; |