1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Glue Code for 3-way parallel assembler optimized version of Twofish
4 *
5 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
6 */
7
8#include <crypto/algapi.h>
9#include <crypto/twofish.h>
10#include <linux/crypto.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/types.h>
14
15#include "twofish.h"
16#include "ecb_cbc_helpers.h"
17
18EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
19EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
20
21static int twofish_setkey_skcipher(struct crypto_skcipher *tfm,
22				   const u8 *key, unsigned int keylen)
23{
24	return twofish_setkey(&tfm->base, key, keylen);
25}
26
27static inline void twofish_enc_blk_3way(const void *ctx, u8 *dst, const u8 *src)
28{
29	__twofish_enc_blk_3way(ctx, dst, src, false);
30}
31
32void twofish_dec_blk_cbc_3way(const void *ctx, u8 *dst, const u8 *src)
33{
34	u8 buf[2][TF_BLOCK_SIZE];
35	const u8 *s = src;
36
37	if (dst == src)
38		s = memcpy(buf, src, sizeof(buf));
39	twofish_dec_blk_3way(ctx, dst, src);
40	crypto_xor(dst + TF_BLOCK_SIZE, s, sizeof(buf));
41
42}
43EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
44
45static int ecb_encrypt(struct skcipher_request *req)
46{
47	ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
48	ECB_BLOCK(3, twofish_enc_blk_3way);
49	ECB_BLOCK(1, twofish_enc_blk);
50	ECB_WALK_END();
51}
52
53static int ecb_decrypt(struct skcipher_request *req)
54{
55	ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
56	ECB_BLOCK(3, twofish_dec_blk_3way);
57	ECB_BLOCK(1, twofish_dec_blk);
58	ECB_WALK_END();
59}
60
61static int cbc_encrypt(struct skcipher_request *req)
62{
63	CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
64	CBC_ENC_BLOCK(twofish_enc_blk);
65	CBC_WALK_END();
66}
67
68static int cbc_decrypt(struct skcipher_request *req)
69{
70	CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
71	CBC_DEC_BLOCK(3, twofish_dec_blk_cbc_3way);
72	CBC_DEC_BLOCK(1, twofish_dec_blk);
73	CBC_WALK_END();
74}
75
76static struct skcipher_alg tf_skciphers[] = {
77	{
78		.base.cra_name		= "ecb(twofish)",
79		.base.cra_driver_name	= "ecb-twofish-3way",
80		.base.cra_priority	= 300,
81		.base.cra_blocksize	= TF_BLOCK_SIZE,
82		.base.cra_ctxsize	= sizeof(struct twofish_ctx),
83		.base.cra_module	= THIS_MODULE,
84		.min_keysize		= TF_MIN_KEY_SIZE,
85		.max_keysize		= TF_MAX_KEY_SIZE,
86		.setkey			= twofish_setkey_skcipher,
87		.encrypt		= ecb_encrypt,
88		.decrypt		= ecb_decrypt,
89	}, {
90		.base.cra_name		= "cbc(twofish)",
91		.base.cra_driver_name	= "cbc-twofish-3way",
92		.base.cra_priority	= 300,
93		.base.cra_blocksize	= TF_BLOCK_SIZE,
94		.base.cra_ctxsize	= sizeof(struct twofish_ctx),
95		.base.cra_module	= THIS_MODULE,
96		.min_keysize		= TF_MIN_KEY_SIZE,
97		.max_keysize		= TF_MAX_KEY_SIZE,
98		.ivsize			= TF_BLOCK_SIZE,
99		.setkey			= twofish_setkey_skcipher,
100		.encrypt		= cbc_encrypt,
101		.decrypt		= cbc_decrypt,
102	},
103};
104
105static bool is_blacklisted_cpu(void)
106{
107	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
108		return false;
109
110	if (boot_cpu_data.x86 == 0x06 &&
111		(boot_cpu_data.x86_model == 0x1c ||
112		 boot_cpu_data.x86_model == 0x26 ||
113		 boot_cpu_data.x86_model == 0x36)) {
114		/*
115		 * On Atom, twofish-3way is slower than original assembler
116		 * implementation. Twofish-3way trades off some performance in
117		 * storing blocks in 64bit registers to allow three blocks to
118		 * be processed parallel. Parallel operation then allows gaining
119		 * more performance than was trade off, on out-of-order CPUs.
120		 * However Atom does not benefit from this parallelism and
121		 * should be blacklisted.
122		 */
123		return true;
124	}
125
126	if (boot_cpu_data.x86 == 0x0f) {
127		/*
128		 * On Pentium 4, twofish-3way is slower than original assembler
129		 * implementation because excessive uses of 64bit rotate and
130		 * left-shifts (which are really slow on P4) needed to store and
131		 * handle 128bit block in two 64bit registers.
132		 */
133		return true;
134	}
135
136	return false;
137}
138
139static int force;
140module_param(force, int, 0);
141MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
142
143static int __init twofish_3way_init(void)
144{
145	if (!force && is_blacklisted_cpu()) {
146		printk(KERN_INFO
147			"twofish-x86_64-3way: performance on this CPU "
148			"would be suboptimal: disabling "
149			"twofish-x86_64-3way.\n");
150		return -ENODEV;
151	}
152
153	return crypto_register_skciphers(tf_skciphers,
154					 ARRAY_SIZE(tf_skciphers));
155}
156
157static void __exit twofish_3way_fini(void)
158{
159	crypto_unregister_skciphers(tf_skciphers, ARRAY_SIZE(tf_skciphers));
160}
161
162module_init(twofish_3way_init);
163module_exit(twofish_3way_fini);
164
165MODULE_LICENSE("GPL");
166MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
167MODULE_ALIAS_CRYPTO("twofish");
168MODULE_ALIAS_CRYPTO("twofish-asm");
169