summaryrefslogtreecommitdiffstats
path: root/drivers/crypto/vmx/ghash.c
blob: 6c999cb01b804839b4565a75a248063c0330dda3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/**
 * GHASH routines supporting VMX instructions on the Power 8
 *
 * Copyright (C) 2015 International Business Machines Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 only.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
 */

#include <linux/types.h>
#include <linux/err.h>
#include <linux/crypto.h>
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <asm/switch_to.h>
#include <crypto/aes.h>
#include <crypto/scatterwalk.h>
#include <crypto/internal/hash.h>
#include <crypto/b128ops.h>

#define IN_INTERRUPT in_interrupt()

#define GHASH_BLOCK_SIZE (16)
#define GHASH_DIGEST_SIZE (16)
#define GHASH_KEY_LEN (16)

void gcm_init_p8(u128 htable[16], const u64 Xi[2]);
void gcm_gmult_p8(u64 Xi[2], const u128 htable[16]);
void gcm_ghash_p8(u64 Xi[2], const u128 htable[16],
		  const u8 *in, size_t len);

struct p8_ghash_ctx {
	u128 htable[16];
	struct crypto_shash *fallback;
};

struct p8_ghash_desc_ctx {
	u64 shash[2];
	u8 buffer[GHASH_DIGEST_SIZE];
	int bytes;
	struct shash_desc fallback_desc;
};

static int p8_ghash_init_tfm(struct crypto_tfm *tfm)
{
	const char *alg;
	struct crypto_shash *fallback;
	struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);

	if (!(alg = crypto_tfm_alg_name(tfm))) {
		printk(KERN_ERR "Failed to get algorithm name.\n");
		return -ENOENT;
	}

	fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
	if (IS_ERR(fallback)) {
		printk(KERN_ERR
		       "Failed to allocate transformation for '%s': %ld\n",
		       alg, PTR_ERR(fallback));
		return PTR_ERR(fallback);
	}
	printk(KERN_INFO "Using '%s' as fallback implementation.\n",
	       crypto_tfm_alg_driver_name(crypto_shash_tfm(fallback)));

	crypto_shash_set_flags(fallback,
			       crypto_shash_get_flags((struct crypto_shash
						       *) tfm));
	ctx->fallback = fallback;

	shash_tfm->descsize = sizeof(struct p8_ghash_desc_ctx)
	    + crypto_shash_descsize(fallback);

	return 0;
}

static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)
{
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);

	if (ctx->fallback) {
		crypto_free_shash(ctx->fallback);
		ctx->fallback = NULL;
	}
}

static int p8_ghash_init(struct shash_desc *desc)
{
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

	dctx->bytes = 0;
	memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
	dctx->fallback_desc.tfm = ctx->fallback;
	dctx->fallback_desc.flags = desc->flags;
	return crypto_shash_init(&dctx->fallback_desc);
}

static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
			   unsigned int keylen)
{
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(tfm));

	if (keylen != GHASH_KEY_LEN)
		return -EINVAL;

	preempt_disable();
	pagefault_disable();
	enable_kernel_vsx();
	gcm_init_p8(ctx->htable, (const u64 *) key);
	disable_kernel_vsx();
	pagefault_enable();
	preempt_enable();
	return crypto_shash_setkey(ctx->fallback, key, keylen);
}

static int p8_ghash_update(struct shash_desc *desc,
			   const u8 *src, unsigned int srclen)
{
	unsigned int len;
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

	if (IN_INTERRUPT) {
		return crypto_shash_update(&dctx->fallback_desc, src,
					   srclen);
	} else {
		if (dctx->bytes) {
			if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
				memcpy(dctx->buffer + dctx->bytes, src,
				       srclen);
				dctx->bytes += srclen;
				return 0;
			}
			memcpy(dctx->buffer + dctx->bytes, src,
			       GHASH_DIGEST_SIZE - dctx->bytes);
			preempt_disable();
			pagefault_disable();
			enable_kernel_vsx();
			gcm_ghash_p8(dctx->shash, ctx->htable,
				     dctx->buffer, GHASH_DIGEST_SIZE);
			disable_kernel_vsx();
			pagefault_enable();
			preempt_enable();
			src += GHASH_DIGEST_SIZE - dctx->bytes;
			srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
			dctx->bytes = 0;
		}
		len = srclen & ~(GHASH_DIGEST_SIZE - 1);
		if (len) {
			preempt_disable();
			pagefault_disable();
			enable_kernel_vsx();
			gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
			disable_kernel_vsx();
			pagefault_enable();
			preempt_enable();
			src += len;
			srclen -= len;
		}
		if (srclen) {
			memcpy(dctx->buffer, src, srclen);
			dctx->bytes = srclen;
		}
		return 0;
	}
}

static int p8_ghash_final(struct shash_desc *desc, u8 *out)
{
	int i;
	struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
	struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

	if (IN_INTERRUPT) {
		return crypto_shash_final(&dctx->fallback_desc, out);
	} else {
		if (dctx->bytes) {
			for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
				dctx->buffer[i] = 0;
			preempt_disable();
			pagefault_disable();
			enable_kernel_vsx();
			gcm_ghash_p8(dctx->shash, ctx->htable,
				     dctx->buffer, GHASH_DIGEST_SIZE);
			disable_kernel_vsx();
			pagefault_enable();
			preempt_enable();
			dctx->bytes = 0;
		}
		memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
		return 0;
	}
}

struct shash_alg p8_ghash_alg = {
	.digestsize = GHASH_DIGEST_SIZE,
	.init = p8_ghash_init,
	.update = p8_ghash_update,
	.final = p8_ghash_final,
	.setkey = p8_ghash_setkey,
	.descsize = sizeof(struct p8_ghash_desc_ctx),
	.base = {
		 .cra_name = "ghash",
		 .cra_driver_name = "p8_ghash",
		 .cra_priority = 1000,
		 .cra_flags = CRYPTO_ALG_TYPE_SHASH | CRYPTO_ALG_NEED_FALLBACK,
		 .cra_blocksize = GHASH_BLOCK_SIZE,
		 .cra_ctxsize = sizeof(struct p8_ghash_ctx),
		 .cra_module = THIS_MODULE,
		 .cra_init = p8_ghash_init_tfm,
		 .cra_exit = p8_ghash_exit_tfm,
	},
};