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 
18 EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
19 EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
20 
21 static 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 
27 static 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 
32 void 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 }
43 EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
44 
45 static 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 
53 static 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 
61 static 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 
68 static 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 
76 static 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 
105 static 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 
139 static int force;
140 module_param(force, int, 0);
141 MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
142 
143 static int __init 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 
157 static void __exit fini(void)
158 {
159 	crypto_unregister_skciphers(tf_skciphers, ARRAY_SIZE(tf_skciphers));
160 }
161 
162 module_init(init);
163 module_exit(fini);
164 
165 MODULE_LICENSE("GPL");
166 MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
167 MODULE_ALIAS_CRYPTO("twofish");
168 MODULE_ALIAS_CRYPTO("twofish-asm");
169