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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 <crypto/skcipher.h>
31
32#include "aesp8-ppc.h"
33
34struct p8_aes_ctr_ctx {
35 struct crypto_skcipher *fallback;
36 struct aes_key enc_key;
37};
38
39static int p8_aes_ctr_init(struct crypto_tfm *tfm)
40{
41 const char *alg = crypto_tfm_alg_name(tfm);
42 struct crypto_skcipher *fallback;
43 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
44
45 fallback = crypto_alloc_skcipher(alg, 0,
46 CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
47 if (IS_ERR(fallback)) {
48 printk(KERN_ERR
49 "Failed to allocate transformation for '%s': %ld\n",
50 alg, PTR_ERR(fallback));
51 return PTR_ERR(fallback);
52 }
53
54 crypto_skcipher_set_flags(
55 fallback,
56 crypto_skcipher_get_flags((struct crypto_skcipher *)tfm));
57 ctx->fallback = fallback;
58
59 return 0;
60}
61
62static void p8_aes_ctr_exit(struct crypto_tfm *tfm)
63{
64 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
65
66 if (ctx->fallback) {
67 crypto_free_skcipher(ctx->fallback);
68 ctx->fallback = NULL;
69 }
70}
71
72static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key,
73 unsigned int keylen)
74{
75 int ret;
76 struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
77
78 preempt_disable();
79 pagefault_disable();
80 enable_kernel_vsx();
81 ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
82 disable_kernel_vsx();
83 pagefault_enable();
84 preempt_enable();
85
86 ret += crypto_skcipher_setkey(ctx->fallback, key, keylen);
87 return ret;
88}
89
90static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
91 struct blkcipher_walk *walk)
92{
93 u8 *ctrblk = walk->iv;
94 u8 keystream[AES_BLOCK_SIZE];
95 u8 *src = walk->src.virt.addr;
96 u8 *dst = walk->dst.virt.addr;
97 unsigned int nbytes = walk->nbytes;
98
99 preempt_disable();
100 pagefault_disable();
101 enable_kernel_vsx();
102 aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
103 disable_kernel_vsx();
104 pagefault_enable();
105 preempt_enable();
106
107 crypto_xor_cpy(dst, keystream, src, nbytes);
108 crypto_inc(ctrblk, AES_BLOCK_SIZE);
109}
110
111static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
112 struct scatterlist *dst,
113 struct scatterlist *src, unsigned int nbytes)
114{
115 int ret;
116 u64 inc;
117 struct blkcipher_walk walk;
118 struct p8_aes_ctr_ctx *ctx =
119 crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
120
121 if (in_interrupt()) {
122 SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback);
123 skcipher_request_set_tfm(req, ctx->fallback);
124 skcipher_request_set_callback(req, desc->flags, NULL, NULL);
125 skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
126 ret = crypto_skcipher_encrypt(req);
127 skcipher_request_zero(req);
128 } else {
129 blkcipher_walk_init(&walk, dst, src, nbytes);
130 ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
131 while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
132 preempt_disable();
133 pagefault_disable();
134 enable_kernel_vsx();
135 aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
136 walk.dst.virt.addr,
137 (nbytes &
138 AES_BLOCK_MASK) /
139 AES_BLOCK_SIZE,
140 &ctx->enc_key,
141 walk.iv);
142 disable_kernel_vsx();
143 pagefault_enable();
144 preempt_enable();
145
146
147 inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE;
148 if (inc > 0)
149 while (inc--)
150 crypto_inc(walk.iv, AES_BLOCK_SIZE);
151
152 nbytes &= AES_BLOCK_SIZE - 1;
153 ret = blkcipher_walk_done(desc, &walk, nbytes);
154 }
155 if (walk.nbytes) {
156 p8_aes_ctr_final(ctx, &walk);
157 ret = blkcipher_walk_done(desc, &walk, 0);
158 }
159 }
160
161 return ret;
162}
163
164struct crypto_alg p8_aes_ctr_alg = {
165 .cra_name = "ctr(aes)",
166 .cra_driver_name = "p8_aes_ctr",
167 .cra_module = THIS_MODULE,
168 .cra_priority = 2000,
169 .cra_type = &crypto_blkcipher_type,
170 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
171 .cra_alignmask = 0,
172 .cra_blocksize = 1,
173 .cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
174 .cra_init = p8_aes_ctr_init,
175 .cra_exit = p8_aes_ctr_exit,
176 .cra_blkcipher = {
177 .ivsize = AES_BLOCK_SIZE,
178 .min_keysize = AES_MIN_KEY_SIZE,
179 .max_keysize = AES_MAX_KEY_SIZE,
180 .setkey = p8_aes_ctr_setkey,
181 .encrypt = p8_aes_ctr_crypt,
182 .decrypt = p8_aes_ctr_crypt,
183 },
184};
185
