summaryrefslogtreecommitdiff
path: root/arch/x86/crypto/twofish_glue_3way.c
blob: 922ab24cce3152c1a2737043d316e015ed794e27 (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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
/*
 * Glue Code for 3-way parallel assembler optimized version of Twofish
 *
 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
 *
 * CBC & ECB parts based on code (crypto/cbc.c,ecb.c) by:
 *   Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 * CTR part based on code (crypto/ctr.c) by:
 *   (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 */

#include <asm/processor.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <crypto/algapi.h>
#include <crypto/twofish.h>
#include <crypto/b128ops.h>
#include <crypto/lrw.h>
#include <crypto/xts.h>

/* regular block cipher functions from twofish_x86_64 module */
asmlinkage void twofish_enc_blk(struct twofish_ctx *ctx, u8 *dst,
				const u8 *src);
asmlinkage void twofish_dec_blk(struct twofish_ctx *ctx, u8 *dst,
				const u8 *src);

/* 3-way parallel cipher functions */
asmlinkage void __twofish_enc_blk_3way(struct twofish_ctx *ctx, u8 *dst,
				       const u8 *src, bool xor);
asmlinkage void twofish_dec_blk_3way(struct twofish_ctx *ctx, u8 *dst,
				     const u8 *src);

static inline void twofish_enc_blk_3way(struct twofish_ctx *ctx, u8 *dst,
					const u8 *src)
{
	__twofish_enc_blk_3way(ctx, dst, src, false);
}

static inline void twofish_enc_blk_xor_3way(struct twofish_ctx *ctx, u8 *dst,
					    const u8 *src)
{
	__twofish_enc_blk_3way(ctx, dst, src, true);
}

static int ecb_crypt(struct blkcipher_desc *desc, struct blkcipher_walk *walk,
		     void (*fn)(struct twofish_ctx *, u8 *, const u8 *),
		     void (*fn_3way)(struct twofish_ctx *, u8 *, const u8 *))
{
	struct twofish_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	unsigned int bsize = TF_BLOCK_SIZE;
	unsigned int nbytes;
	int err;

	err = blkcipher_walk_virt(desc, walk);

	while ((nbytes = walk->nbytes)) {
		u8 *wsrc = walk->src.virt.addr;
		u8 *wdst = walk->dst.virt.addr;

		/* Process three block batch */
		if (nbytes >= bsize * 3) {
			do {
				fn_3way(ctx, wdst, wsrc);

				wsrc += bsize * 3;
				wdst += bsize * 3;
				nbytes -= bsize * 3;
			} while (nbytes >= bsize * 3);

			if (nbytes < bsize)
				goto done;
		}

		/* Handle leftovers */
		do {
			fn(ctx, wdst, wsrc);

			wsrc += bsize;
			wdst += bsize;
			nbytes -= bsize;
		} while (nbytes >= bsize);

done:
		err = blkcipher_walk_done(desc, walk, nbytes);
	}

	return err;
}

static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct blkcipher_walk walk;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	return ecb_crypt(desc, &walk, twofish_enc_blk, twofish_enc_blk_3way);
}

static int ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct blkcipher_walk walk;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	return ecb_crypt(desc, &walk, twofish_dec_blk, twofish_dec_blk_3way);
}

static unsigned int __cbc_encrypt(struct blkcipher_desc *desc,
				  struct blkcipher_walk *walk)
{
	struct twofish_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	unsigned int bsize = TF_BLOCK_SIZE;
	unsigned int nbytes = walk->nbytes;
	u128 *src = (u128 *)walk->src.virt.addr;
	u128 *dst = (u128 *)walk->dst.virt.addr;
	u128 *iv = (u128 *)walk->iv;

	do {
		u128_xor(dst, src, iv);
		twofish_enc_blk(ctx, (u8 *)dst, (u8 *)dst);
		iv = dst;

		src += 1;
		dst += 1;
		nbytes -= bsize;
	} while (nbytes >= bsize);

	u128_xor((u128 *)walk->iv, (u128 *)walk->iv, iv);
	return nbytes;
}

static int cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		nbytes = __cbc_encrypt(desc, &walk);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static unsigned int __cbc_decrypt(struct blkcipher_desc *desc,
				  struct blkcipher_walk *walk)
{
	struct twofish_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	unsigned int bsize = TF_BLOCK_SIZE;
	unsigned int nbytes = walk->nbytes;
	u128 *src = (u128 *)walk->src.virt.addr;
	u128 *dst = (u128 *)walk->dst.virt.addr;
	u128 ivs[3 - 1];
	u128 last_iv;

	/* Start of the last block. */
	src += nbytes / bsize - 1;
	dst += nbytes / bsize - 1;

	last_iv = *src;

	/* Process three block batch */
	if (nbytes >= bsize * 3) {
		do {
			nbytes -= bsize * (3 - 1);
			src -= 3 - 1;
			dst -= 3 - 1;

			ivs[0] = src[0];
			ivs[1] = src[1];

			twofish_dec_blk_3way(ctx, (u8 *)dst, (u8 *)src);

			u128_xor(dst + 1, dst + 1, ivs + 0);
			u128_xor(dst + 2, dst + 2, ivs + 1);

			nbytes -= bsize;
			if (nbytes < bsize)
				goto done;

			u128_xor(dst, dst, src - 1);
			src -= 1;
			dst -= 1;
		} while (nbytes >= bsize * 3);

		if (nbytes < bsize)
			goto done;
	}

	/* Handle leftovers */
	for (;;) {
		twofish_dec_blk(ctx, (u8 *)dst, (u8 *)src);

		nbytes -= bsize;
		if (nbytes < bsize)
			break;

		u128_xor(dst, dst, src - 1);
		src -= 1;
		dst -= 1;
	}

done:
	u128_xor(dst, dst, (u128 *)walk->iv);
	*(u128 *)walk->iv = last_iv;

	return nbytes;
}

static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt(desc, &walk);

	while ((nbytes = walk.nbytes)) {
		nbytes = __cbc_decrypt(desc, &walk);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	return err;
}

static inline void u128_to_be128(be128 *dst, const u128 *src)
{
	dst->a = cpu_to_be64(src->a);
	dst->b = cpu_to_be64(src->b);
}

static inline void be128_to_u128(u128 *dst, const be128 *src)
{
	dst->a = be64_to_cpu(src->a);
	dst->b = be64_to_cpu(src->b);
}

static inline void u128_inc(u128 *i)
{
	i->b++;
	if (!i->b)
		i->a++;
}

static void ctr_crypt_final(struct blkcipher_desc *desc,
			    struct blkcipher_walk *walk)
{
	struct twofish_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	u8 *ctrblk = walk->iv;
	u8 keystream[TF_BLOCK_SIZE];
	u8 *src = walk->src.virt.addr;
	u8 *dst = walk->dst.virt.addr;
	unsigned int nbytes = walk->nbytes;

	twofish_enc_blk(ctx, keystream, ctrblk);
	crypto_xor(keystream, src, nbytes);
	memcpy(dst, keystream, nbytes);

	crypto_inc(ctrblk, TF_BLOCK_SIZE);
}

static unsigned int __ctr_crypt(struct blkcipher_desc *desc,
				struct blkcipher_walk *walk)
{
	struct twofish_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	unsigned int bsize = TF_BLOCK_SIZE;
	unsigned int nbytes = walk->nbytes;
	u128 *src = (u128 *)walk->src.virt.addr;
	u128 *dst = (u128 *)walk->dst.virt.addr;
	u128 ctrblk;
	be128 ctrblocks[3];

	be128_to_u128(&ctrblk, (be128 *)walk->iv);

	/* Process three block batch */
	if (nbytes >= bsize * 3) {
		do {
			if (dst != src) {
				dst[0] = src[0];
				dst[1] = src[1];
				dst[2] = src[2];
			}

			/* create ctrblks for parallel encrypt */
			u128_to_be128(&ctrblocks[0], &ctrblk);
			u128_inc(&ctrblk);
			u128_to_be128(&ctrblocks[1], &ctrblk);
			u128_inc(&ctrblk);
			u128_to_be128(&ctrblocks[2], &ctrblk);
			u128_inc(&ctrblk);

			twofish_enc_blk_xor_3way(ctx, (u8 *)dst,
						 (u8 *)ctrblocks);

			src += 3;
			dst += 3;
			nbytes -= bsize * 3;
		} while (nbytes >= bsize * 3);

		if (nbytes < bsize)
			goto done;
	}

	/* Handle leftovers */
	do {
		if (dst != src)
			*dst = *src;

		u128_to_be128(&ctrblocks[0], &ctrblk);
		u128_inc(&ctrblk);

		twofish_enc_blk(ctx, (u8 *)ctrblocks, (u8 *)ctrblocks);
		u128_xor(dst, dst, (u128 *)ctrblocks);

		src += 1;
		dst += 1;
		nbytes -= bsize;
	} while (nbytes >= bsize);

done:
	u128_to_be128((be128 *)walk->iv, &ctrblk);
	return nbytes;
}

static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		     struct scatterlist *src, unsigned int nbytes)
{
	struct blkcipher_walk walk;
	int err;

	blkcipher_walk_init(&walk, dst, src, nbytes);
	err = blkcipher_walk_virt_block(desc, &walk, TF_BLOCK_SIZE);

	while ((nbytes = walk.nbytes) >= TF_BLOCK_SIZE) {
		nbytes = __ctr_crypt(desc, &walk);
		err = blkcipher_walk_done(desc, &walk, nbytes);
	}

	if (walk.nbytes) {
		ctr_crypt_final(desc, &walk);
		err = blkcipher_walk_done(desc, &walk, 0);
	}

	return err;
}

static void encrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
	const unsigned int bsize = TF_BLOCK_SIZE;
	struct twofish_ctx *ctx = priv;
	int i;

	if (nbytes == 3 * bsize) {
		twofish_enc_blk_3way(ctx, srcdst, srcdst);
		return;
	}

	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
		twofish_enc_blk(ctx, srcdst, srcdst);
}

static void decrypt_callback(void *priv, u8 *srcdst, unsigned int nbytes)
{
	const unsigned int bsize = TF_BLOCK_SIZE;
	struct twofish_ctx *ctx = priv;
	int i;

	if (nbytes == 3 * bsize) {
		twofish_dec_blk_3way(ctx, srcdst, srcdst);
		return;
	}

	for (i = 0; i < nbytes / bsize; i++, srcdst += bsize)
		twofish_dec_blk(ctx, srcdst, srcdst);
}

struct twofish_lrw_ctx {
	struct lrw_table_ctx lrw_table;
	struct twofish_ctx twofish_ctx;
};

static int lrw_twofish_setkey(struct crypto_tfm *tfm, const u8 *key,
			      unsigned int keylen)
{
	struct twofish_lrw_ctx *ctx = crypto_tfm_ctx(tfm);
	int err;

	err = __twofish_setkey(&ctx->twofish_ctx, key, keylen - TF_BLOCK_SIZE,
			       &tfm->crt_flags);
	if (err)
		return err;

	return lrw_init_table(&ctx->lrw_table, key + keylen - TF_BLOCK_SIZE);
}

static int lrw_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[3];
	struct lrw_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.table_ctx = &ctx->lrw_table,
		.crypt_ctx = &ctx->twofish_ctx,
		.crypt_fn = encrypt_callback,
	};

	return lrw_crypt(desc, dst, src, nbytes, &req);
}

static int lrw_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_lrw_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[3];
	struct lrw_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.table_ctx = &ctx->lrw_table,
		.crypt_ctx = &ctx->twofish_ctx,
		.crypt_fn = decrypt_callback,
	};

	return lrw_crypt(desc, dst, src, nbytes, &req);
}

static void lrw_exit_tfm(struct crypto_tfm *tfm)
{
	struct twofish_lrw_ctx *ctx = crypto_tfm_ctx(tfm);

	lrw_free_table(&ctx->lrw_table);
}

struct twofish_xts_ctx {
	struct twofish_ctx tweak_ctx;
	struct twofish_ctx crypt_ctx;
};

static int xts_twofish_setkey(struct crypto_tfm *tfm, const u8 *key,
			      unsigned int keylen)
{
	struct twofish_xts_ctx *ctx = crypto_tfm_ctx(tfm);
	u32 *flags = &tfm->crt_flags;
	int err;

	/* key consists of keys of equal size concatenated, therefore
	 * the length must be even
	 */
	if (keylen % 2) {
		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
		return -EINVAL;
	}

	/* first half of xts-key is for crypt */
	err = __twofish_setkey(&ctx->crypt_ctx, key, keylen / 2, flags);
	if (err)
		return err;

	/* second half of xts-key is for tweak */
	return __twofish_setkey(&ctx->tweak_ctx, key + keylen / 2, keylen / 2,
				flags);
}

static int xts_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[3];
	struct xts_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.tweak_ctx = &ctx->tweak_ctx,
		.tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
		.crypt_ctx = &ctx->crypt_ctx,
		.crypt_fn = encrypt_callback,
	};

	return xts_crypt(desc, dst, src, nbytes, &req);
}

static int xts_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
		       struct scatterlist *src, unsigned int nbytes)
{
	struct twofish_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
	be128 buf[3];
	struct xts_crypt_req req = {
		.tbuf = buf,
		.tbuflen = sizeof(buf),

		.tweak_ctx = &ctx->tweak_ctx,
		.tweak_fn = XTS_TWEAK_CAST(twofish_enc_blk),
		.crypt_ctx = &ctx->crypt_ctx,
		.crypt_fn = decrypt_callback,
	};

	return xts_crypt(desc, dst, src, nbytes, &req);
}

static struct crypto_alg tf_algs[5] = { {
	.cra_name		= "ecb(twofish)",
	.cra_driver_name	= "ecb-twofish-3way",
	.cra_priority		= 300,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(tf_algs[0].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= ecb_encrypt,
			.decrypt	= ecb_decrypt,
		},
	},
}, {
	.cra_name		= "cbc(twofish)",
	.cra_driver_name	= "cbc-twofish-3way",
	.cra_priority		= 300,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(tf_algs[1].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= cbc_encrypt,
			.decrypt	= cbc_decrypt,
		},
	},
}, {
	.cra_name		= "ctr(twofish)",
	.cra_driver_name	= "ctr-twofish-3way",
	.cra_priority		= 300,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= 1,
	.cra_ctxsize		= sizeof(struct twofish_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(tf_algs[2].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= twofish_setkey,
			.encrypt	= ctr_crypt,
			.decrypt	= ctr_crypt,
		},
	},
}, {
	.cra_name		= "lrw(twofish)",
	.cra_driver_name	= "lrw-twofish-3way",
	.cra_priority		= 300,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_lrw_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(tf_algs[3].cra_list),
	.cra_exit		= lrw_exit_tfm,
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE + TF_BLOCK_SIZE,
			.max_keysize	= TF_MAX_KEY_SIZE + TF_BLOCK_SIZE,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= lrw_twofish_setkey,
			.encrypt	= lrw_encrypt,
			.decrypt	= lrw_decrypt,
		},
	},
}, {
	.cra_name		= "xts(twofish)",
	.cra_driver_name	= "xts-twofish-3way",
	.cra_priority		= 300,
	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
	.cra_blocksize		= TF_BLOCK_SIZE,
	.cra_ctxsize		= sizeof(struct twofish_xts_ctx),
	.cra_alignmask		= 0,
	.cra_type		= &crypto_blkcipher_type,
	.cra_module		= THIS_MODULE,
	.cra_list		= LIST_HEAD_INIT(tf_algs[4].cra_list),
	.cra_u = {
		.blkcipher = {
			.min_keysize	= TF_MIN_KEY_SIZE * 2,
			.max_keysize	= TF_MAX_KEY_SIZE * 2,
			.ivsize		= TF_BLOCK_SIZE,
			.setkey		= xts_twofish_setkey,
			.encrypt	= xts_encrypt,
			.decrypt	= xts_decrypt,
		},
	},
} };

static bool is_blacklisted_cpu(void)
{
	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
		return false;

	if (boot_cpu_data.x86 == 0x06 &&
		(boot_cpu_data.x86_model == 0x1c ||
		 boot_cpu_data.x86_model == 0x26 ||
		 boot_cpu_data.x86_model == 0x36)) {
		/*
		 * On Atom, twofish-3way is slower than original assembler
		 * implementation. Twofish-3way trades off some performance in
		 * storing blocks in 64bit registers to allow three blocks to
		 * be processed parallel. Parallel operation then allows gaining
		 * more performance than was trade off, on out-of-order CPUs.
		 * However Atom does not benefit from this parallellism and
		 * should be blacklisted.
		 */
		return true;
	}

	if (boot_cpu_data.x86 == 0x0f) {
		/*
		 * On Pentium 4, twofish-3way is slower than original assembler
		 * implementation because excessive uses of 64bit rotate and
		 * left-shifts (which are really slow on P4) needed to store and
		 * handle 128bit block in two 64bit registers.
		 */
		return true;
	}

	return false;
}

static int force;
module_param(force, int, 0);
MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");

static int __init init(void)
{
	if (!force && is_blacklisted_cpu()) {
		printk(KERN_INFO
			"twofish-x86_64-3way: performance on this CPU "
			"would be suboptimal: disabling "
			"twofish-x86_64-3way.\n");
		return -ENODEV;
	}

	return crypto_register_algs(tf_algs, ARRAY_SIZE(tf_algs));
}

static void __exit fini(void)
{
	crypto_unregister_algs(tf_algs, ARRAY_SIZE(tf_algs));
}

module_init(init);
module_exit(fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
MODULE_ALIAS("twofish");
MODULE_ALIAS("twofish-asm");