twofish_glue_3way.c

  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 <asm/cpu_device_id.h>
  9#include <crypto/algapi.h>
 10#include <crypto/twofish.h>
 11#include <linux/crypto.h>
 12#include <linux/export.h>
 13#include <linux/init.h>
 14#include <linux/module.h>
 15#include <linux/types.h>
 16
 17#include "twofish.h"
 18#include "ecb_cbc_helpers.h"
 19
 20EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
 21EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
 22
 23static int twofish_setkey_skcipher(struct crypto_skcipher *tfm,
 24				   const u8 *key, unsigned int keylen)
 25{
 26	return twofish_setkey(&tfm->base, key, keylen);
 27}
 28
 29static inline void twofish_enc_blk_3way(const void *ctx, u8 *dst, const u8 *src)
 30{
 31	__twofish_enc_blk_3way(ctx, dst, src, false);
 32}
 33
 34void twofish_dec_blk_cbc_3way(const void *ctx, u8 *dst, const u8 *src)
 35{
 36	u8 buf[2][TF_BLOCK_SIZE];
 37	const u8 *s = src;
 38
 39	if (dst == src)
 40		s = memcpy(buf, src, sizeof(buf));
 41	twofish_dec_blk_3way(ctx, dst, src);
 42	crypto_xor(dst + TF_BLOCK_SIZE, s, sizeof(buf));
 43
 44}
 45EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
 46
 47static int ecb_encrypt(struct skcipher_request *req)
 48{
 49	ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
 50	ECB_BLOCK(3, twofish_enc_blk_3way);
 51	ECB_BLOCK(1, twofish_enc_blk);
 52	ECB_WALK_END();
 53}
 54
 55static int ecb_decrypt(struct skcipher_request *req)
 56{
 57	ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
 58	ECB_BLOCK(3, twofish_dec_blk_3way);
 59	ECB_BLOCK(1, twofish_dec_blk);
 60	ECB_WALK_END();
 61}
 62
 63static int cbc_encrypt(struct skcipher_request *req)
 64{
 65	CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
 66	CBC_ENC_BLOCK(twofish_enc_blk);
 67	CBC_WALK_END();
 68}
 69
 70static int cbc_decrypt(struct skcipher_request *req)
 71{
 72	CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
 73	CBC_DEC_BLOCK(3, twofish_dec_blk_cbc_3way);
 74	CBC_DEC_BLOCK(1, twofish_dec_blk);
 75	CBC_WALK_END();
 76}
 77
 78static struct skcipher_alg tf_skciphers[] = {
 79	{
 80		.base.cra_name		= "ecb(twofish)",
 81		.base.cra_driver_name	= "ecb-twofish-3way",
 82		.base.cra_priority	= 300,
 83		.base.cra_blocksize	= TF_BLOCK_SIZE,
 84		.base.cra_ctxsize	= sizeof(struct twofish_ctx),
 85		.base.cra_module	= THIS_MODULE,
 86		.min_keysize		= TF_MIN_KEY_SIZE,
 87		.max_keysize		= TF_MAX_KEY_SIZE,
 88		.setkey			= twofish_setkey_skcipher,
 89		.encrypt		= ecb_encrypt,
 90		.decrypt		= ecb_decrypt,
 91	}, {
 92		.base.cra_name		= "cbc(twofish)",
 93		.base.cra_driver_name	= "cbc-twofish-3way",
 94		.base.cra_priority	= 300,
 95		.base.cra_blocksize	= TF_BLOCK_SIZE,
 96		.base.cra_ctxsize	= sizeof(struct twofish_ctx),
 97		.base.cra_module	= THIS_MODULE,
 98		.min_keysize		= TF_MIN_KEY_SIZE,
 99		.max_keysize		= TF_MAX_KEY_SIZE,
100		.ivsize			= TF_BLOCK_SIZE,
101		.setkey			= twofish_setkey_skcipher,
102		.encrypt		= cbc_encrypt,
103		.decrypt		= cbc_decrypt,
104	},
105};
106
107static bool is_blacklisted_cpu(void)
108{
109	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
110		return false;
111
112	switch (boot_cpu_data.x86_vfm) {
113	case INTEL_ATOM_BONNELL:
114	case INTEL_ATOM_BONNELL_MID:
115	case INTEL_ATOM_SALTWELL:
116		/*
117		 * On Atom, twofish-3way is slower than original assembler
118		 * implementation. Twofish-3way trades off some performance in
119		 * storing blocks in 64bit registers to allow three blocks to
120		 * be processed parallel. Parallel operation then allows gaining
121		 * more performance than was trade off, on out-of-order CPUs.
122		 * However Atom does not benefit from this parallelism and
123		 * should be blacklisted.
124		 */
125		return true;
126	}
127
128	if (boot_cpu_data.x86 == 0x0f) {
129		/*
130		 * On Pentium 4, twofish-3way is slower than original assembler
131		 * implementation because excessive uses of 64bit rotate and
132		 * left-shifts (which are really slow on P4) needed to store and
133		 * handle 128bit block in two 64bit registers.
134		 */
135		return true;
136	}
137
138	return false;
139}
140
141static int force;
142module_param(force, int, 0);
143MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
144
145static int __init twofish_3way_init(void)
146{
147	if (!force && is_blacklisted_cpu()) {
148		printk(KERN_INFO
149			"twofish-x86_64-3way: performance on this CPU "
150			"would be suboptimal: disabling "
151			"twofish-x86_64-3way.\n");
152		return -ENODEV;
153	}
154
155	return crypto_register_skciphers(tf_skciphers,
156					 ARRAY_SIZE(tf_skciphers));
157}
158
159static void __exit twofish_3way_fini(void)
160{
161	crypto_unregister_skciphers(tf_skciphers, ARRAY_SIZE(tf_skciphers));
162}
163
164module_init(twofish_3way_init);
165module_exit(twofish_3way_fini);
166
167MODULE_LICENSE("GPL");
168MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
169MODULE_ALIAS_CRYPTO("twofish");
170MODULE_ALIAS_CRYPTO("twofish-asm");