1 /**
2 * GHASH 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/ghash.h>
30 #include <crypto/scatterwalk.h>
31 #include <crypto/internal/hash.h>
32 #include <crypto/b128ops.h>
33
34 #define IN_INTERRUPT in_interrupt()
35
36 void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
37 void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
38 void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
39 const u8 *in, size_t len);
40
41 struct p8_ghash_ctx {
42 u128 htable[16];
43 struct crypto_shash *fallback;
44 };
45
46 struct p8_ghash_desc_ctx {
47 u64 shash[2];
48 u8 buffer[GHASH_DIGEST_SIZE];
49 int bytes;
50 struct shash_desc fallback_desc;
51 };
52
p8_ghash_init_tfm(struct crypto_tfm * tfm)53 static int p8_ghash_init_tfm(struct crypto_tfm *tfm)
54 {
55 const char *alg = "ghash-generic";
56 struct crypto_shash *fallback;
57 struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);
58 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
59
60 fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
61 if (IS_ERR(fallback)) {
62 printk(KERN_ERR
63 "Failed to allocate transformation for '%s': %ld\n",
64 alg, PTR_ERR(fallback));
65 return PTR_ERR(fallback);
66 }
67
68 crypto_shash_set_flags(fallback,
69 crypto_shash_get_flags((struct crypto_shash
70 *) tfm));
71
72 /* Check if the descsize defined in the algorithm is still enough. */
73 if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)
74 + crypto_shash_descsize(fallback)) {
75 printk(KERN_ERR
76 "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",
77 alg,
78 shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),
79 crypto_shash_descsize(fallback));
80 return -EINVAL;
81 }
82 ctx->fallback = fallback;
83
84 return 0;
85 }
86
p8_ghash_exit_tfm(struct crypto_tfm * tfm)87 static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)
88 {
89 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
90
91 if (ctx->fallback) {
92 crypto_free_shash(ctx->fallback);
93 ctx->fallback = NULL;
94 }
95 }
96
p8_ghash_init(struct shash_desc * desc)97 static int p8_ghash_init(struct shash_desc *desc)
98 {
99 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
100 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
101
102 dctx->bytes = 0;
103 memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
104 dctx->fallback_desc.tfm = ctx->fallback;
105 dctx->fallback_desc.flags = desc->flags;
106 return crypto_shash_init(&dctx->fallback_desc);
107 }
108
p8_ghash_setkey(struct crypto_shash * tfm,const u8 * key,unsigned int keylen)109 static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
110 unsigned int keylen)
111 {
112 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));
113
114 if (keylen != GHASH_BLOCK_SIZE)
115 return -EINVAL;
116
117 preempt_disable();
118 pagefault_disable();
119 enable_kernel_vsx();
120 gcm_init_p8(ctx->htable, (const u64 *) key);
121 disable_kernel_vsx();
122 pagefault_enable();
123 preempt_enable();
124 return crypto_shash_setkey(ctx->fallback, key, keylen);
125 }
126
p8_ghash_update(struct shash_desc * desc,const u8 * src,unsigned int srclen)127 static int p8_ghash_update(struct shash_desc *desc,
128 const u8 *src, unsigned int srclen)
129 {
130 unsigned int len;
131 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
132 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
133
134 if (IN_INTERRUPT) {
135 return crypto_shash_update(&dctx->fallback_desc, src,
136 srclen);
137 } else {
138 if (dctx->bytes) {
139 if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
140 memcpy(dctx->buffer + dctx->bytes, src,
141 srclen);
142 dctx->bytes += srclen;
143 return 0;
144 }
145 memcpy(dctx->buffer + dctx->bytes, src,
146 GHASH_DIGEST_SIZE - dctx->bytes);
147 preempt_disable();
148 pagefault_disable();
149 enable_kernel_vsx();
150 gcm_ghash_p8(dctx->shash, ctx->htable,
151 dctx->buffer, GHASH_DIGEST_SIZE);
152 disable_kernel_vsx();
153 pagefault_enable();
154 preempt_enable();
155 src += GHASH_DIGEST_SIZE - dctx->bytes;
156 srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
157 dctx->bytes = 0;
158 }
159 len = srclen & ~(GHASH_DIGEST_SIZE - 1);
160 if (len) {
161 preempt_disable();
162 pagefault_disable();
163 enable_kernel_vsx();
164 gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
165 disable_kernel_vsx();
166 pagefault_enable();
167 preempt_enable();
168 src += len;
169 srclen -= len;
170 }
171 if (srclen) {
172 memcpy(dctx->buffer, src, srclen);
173 dctx->bytes = srclen;
174 }
175 return 0;
176 }
177 }
178
p8_ghash_final(struct shash_desc * desc,u8 * out)179 static int p8_ghash_final(struct shash_desc *desc, u8 *out)
180 {
181 int i;
182 struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
183 struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
184
185 if (IN_INTERRUPT) {
186 return crypto_shash_final(&dctx->fallback_desc, out);
187 } else {
188 if (dctx->bytes) {
189 for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
190 dctx->buffer[i] = 0;
191 preempt_disable();
192 pagefault_disable();
193 enable_kernel_vsx();
194 gcm_ghash_p8(dctx->shash, ctx->htable,
195 dctx->buffer, GHASH_DIGEST_SIZE);
196 disable_kernel_vsx();
197 pagefault_enable();
198 preempt_enable();
199 dctx->bytes = 0;
200 }
201 memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
202 return 0;
203 }
204 }
205
206 struct shash_alg p8_ghash_alg = {
207 .digestsize = GHASH_DIGEST_SIZE,
208 .init = p8_ghash_init,
209 .update = p8_ghash_update,
210 .final = p8_ghash_final,
211 .setkey = p8_ghash_setkey,
212 .descsize = sizeof(struct p8_ghash_desc_ctx)
213 + sizeof(struct ghash_desc_ctx),
214 .base = {
215 .cra_name = "ghash",
216 .cra_driver_name = "p8_ghash",
217 .cra_priority = 1000,
218 .cra_flags = CRYPTO_ALG_NEED_FALLBACK,
219 .cra_blocksize = GHASH_BLOCK_SIZE,
220 .cra_ctxsize = sizeof(struct p8_ghash_ctx),
221 .cra_module = THIS_MODULE,
222 .cra_init = p8_ghash_init_tfm,
223 .cra_exit = p8_ghash_exit_tfm,
224 },
225 };
226
