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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
32struct p8_aes_ctr_ctx {
33 struct crypto_blkcipher *fallback;
34 struct aes_key enc_key;
35};
36
37static 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 =
49 crypto_alloc_blkcipher(alg, 0, 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 printk(KERN_INFO "Using '%s' as fallback implementation.\n",
57 crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
58
59 crypto_blkcipher_set_flags(
60 fallback,
61 crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
62 ctx->fallback = fallback;
63
64 return 0;
65}
66
67static void p8_aes_ctr_exit(struct crypto_tfm *tfm)
68{
69 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
70
71 if (ctx->fallback) {
72 crypto_free_blkcipher(ctx->fallback);
73 ctx->fallback = NULL;
74 }
75}
76
77static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key,
78 unsigned int keylen)
79{
80 int ret;
81 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
82
83 pagefault_disable();
84 enable_kernel_vsx();
85 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
86 disable_kernel_vsx();
87 pagefault_enable();
88
89 ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
90 return ret;
91}
92
93static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
94 struct blkcipher_walk *walk)
95{
96 u8 *ctrblk = walk->iv;
97 u8 keystream[AES_BLOCK_SIZE];
98 u8 *src = walk->src.virt.addr;
99 u8 *dst = walk->dst.virt.addr;
100 unsigned int nbytes = walk->nbytes;
101
102 pagefault_disable();
103 enable_kernel_vsx();
104 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
105 disable_kernel_vsx();
106 pagefault_enable();
107
108 crypto_xor(keystream, src, nbytes);
109 memcpy(dst, keystream, nbytes);
110 crypto_inc(ctrblk, AES_BLOCK_SIZE);
111}
112
113static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
114 struct scatterlist *dst,
115 struct scatterlist *src, unsigned int nbytes)
116{
117 int ret;
118 u64 inc;
119 struct blkcipher_walk walk;
120 struct p8_aes_ctr_ctx *ctx =
121 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
122 struct blkcipher_desc fallback_desc = {
123 .tfm = ctx->fallback,
124 .info = desc->info,
125 .flags = desc->flags
126 };
127
128 if (in_interrupt()) {
129 ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
130 nbytes);
131 } else {
132 blkcipher_walk_init(&walk, dst, src, nbytes);
133 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
134 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
135 pagefault_disable();
136 enable_kernel_vsx();
137 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
138 walk.dst.virt.addr,
139 (nbytes &
140 AES_BLOCK_MASK) /
141 AES_BLOCK_SIZE,
142 &ctx->enc_key,
143 walk.iv);
144 disable_kernel_vsx();
145 pagefault_enable();
146
147
148 inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE;
149 if (inc > 0)
150 while (inc--)
151 crypto_inc(walk.iv, AES_BLOCK_SIZE);
152
153 nbytes &= AES_BLOCK_SIZE - 1;
154 ret = blkcipher_walk_done(desc, &walk, nbytes);
155 }
156 if (walk.nbytes) {
157 p8_aes_ctr_final(ctx, &walk);
158 ret = blkcipher_walk_done(desc, &walk, 0);
159 }
160 }
161
162 return ret;
163}
164
165struct crypto_alg p8_aes_ctr_alg = {
166 .cra_name = "ctr(aes)",
167 .cra_driver_name = "p8_aes_ctr",
168 .cra_module = THIS_MODULE,
169 .cra_priority = 1000,
170 .cra_type = &crypto_blkcipher_type,
171 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
172 .cra_alignmask = 0,
173 .cra_blocksize = 1,
174 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
175 .cra_init = p8_aes_ctr_init,
176 .cra_exit = p8_aes_ctr_exit,
177 .cra_blkcipher = {
178 .ivsize = AES_BLOCK_SIZE,
179 .min_keysize = AES_MIN_KEY_SIZE,
180 .max_keysize = AES_MAX_KEY_SIZE,
181 .setkey = p8_aes_ctr_setkey,
182 .encrypt = p8_aes_ctr_crypt,
183 .decrypt = p8_aes_ctr_crypt,
184 },
185};
186
