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