summaryrefslogtreecommitdiff
path: root/arch/arm64/crypto/aes-modes.S
blob: 5abc834271f4a61097e7a71d365d2fef8d51b12b (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
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * linux/arch/arm64/crypto/aes-modes.S - chaining mode wrappers for AES
 *
 * Copyright (C) 2013 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
 */

/* included by aes-ce.S and aes-neon.S */

	.text
	.align		4

#ifndef MAX_STRIDE
#define MAX_STRIDE	4
#endif

#if MAX_STRIDE == 4
#define ST4(x...) x
#define ST5(x...)
#else
#define ST4(x...)
#define ST5(x...) x
#endif

SYM_FUNC_START_LOCAL(aes_encrypt_block4x)
	encrypt_block4x	v0, v1, v2, v3, w3, x2, x8, w7
	ret
SYM_FUNC_END(aes_encrypt_block4x)

SYM_FUNC_START_LOCAL(aes_decrypt_block4x)
	decrypt_block4x	v0, v1, v2, v3, w3, x2, x8, w7
	ret
SYM_FUNC_END(aes_decrypt_block4x)

#if MAX_STRIDE == 5
SYM_FUNC_START_LOCAL(aes_encrypt_block5x)
	encrypt_block5x	v0, v1, v2, v3, v4, w3, x2, x8, w7
	ret
SYM_FUNC_END(aes_encrypt_block5x)

SYM_FUNC_START_LOCAL(aes_decrypt_block5x)
	decrypt_block5x	v0, v1, v2, v3, v4, w3, x2, x8, w7
	ret
SYM_FUNC_END(aes_decrypt_block5x)
#endif

	/*
	 * aes_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int blocks)
	 * aes_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int blocks)
	 */

AES_FUNC_START(aes_ecb_encrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	enc_prepare	w3, x2, x5

.LecbencloopNx:
	subs		w4, w4, #MAX_STRIDE
	bmi		.Lecbenc1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 pt blocks */
ST4(	bl		aes_encrypt_block4x		)
ST5(	ld1		{v4.16b}, [x1], #16		)
ST5(	bl		aes_encrypt_block5x		)
	st1		{v0.16b-v3.16b}, [x0], #64
ST5(	st1		{v4.16b}, [x0], #16		)
	b		.LecbencloopNx
.Lecbenc1x:
	adds		w4, w4, #MAX_STRIDE
	beq		.Lecbencout
.Lecbencloop:
	ld1		{v0.16b}, [x1], #16		/* get next pt block */
	encrypt_block	v0, w3, x2, x5, w6
	st1		{v0.16b}, [x0], #16
	subs		w4, w4, #1
	bne		.Lecbencloop
.Lecbencout:
	ldp		x29, x30, [sp], #16
	ret
AES_FUNC_END(aes_ecb_encrypt)


AES_FUNC_START(aes_ecb_decrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	dec_prepare	w3, x2, x5

.LecbdecloopNx:
	subs		w4, w4, #MAX_STRIDE
	bmi		.Lecbdec1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 ct blocks */
ST4(	bl		aes_decrypt_block4x		)
ST5(	ld1		{v4.16b}, [x1], #16		)
ST5(	bl		aes_decrypt_block5x		)
	st1		{v0.16b-v3.16b}, [x0], #64
ST5(	st1		{v4.16b}, [x0], #16		)
	b		.LecbdecloopNx
.Lecbdec1x:
	adds		w4, w4, #MAX_STRIDE
	beq		.Lecbdecout
.Lecbdecloop:
	ld1		{v0.16b}, [x1], #16		/* get next ct block */
	decrypt_block	v0, w3, x2, x5, w6
	st1		{v0.16b}, [x0], #16
	subs		w4, w4, #1
	bne		.Lecbdecloop
.Lecbdecout:
	ldp		x29, x30, [sp], #16
	ret
AES_FUNC_END(aes_ecb_decrypt)


	/*
	 * aes_cbc_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int blocks, u8 iv[])
	 * aes_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int blocks, u8 iv[])
	 * aes_essiv_cbc_encrypt(u8 out[], u8 const in[], u32 const rk1[],
	 *			 int rounds, int blocks, u8 iv[],
	 *			 u32 const rk2[]);
	 * aes_essiv_cbc_decrypt(u8 out[], u8 const in[], u32 const rk1[],
	 *			 int rounds, int blocks, u8 iv[],
	 *			 u32 const rk2[]);
	 */

AES_FUNC_START(aes_essiv_cbc_encrypt)
	ld1		{v4.16b}, [x5]			/* get iv */

	mov		w8, #14				/* AES-256: 14 rounds */
	enc_prepare	w8, x6, x7
	encrypt_block	v4, w8, x6, x7, w9
	enc_switch_key	w3, x2, x6
	b		.Lcbcencloop4x

AES_FUNC_START(aes_cbc_encrypt)
	ld1		{v4.16b}, [x5]			/* get iv */
	enc_prepare	w3, x2, x6

.Lcbcencloop4x:
	subs		w4, w4, #4
	bmi		.Lcbcenc1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 pt blocks */
	eor		v0.16b, v0.16b, v4.16b		/* ..and xor with iv */
	encrypt_block	v0, w3, x2, x6, w7
	eor		v1.16b, v1.16b, v0.16b
	encrypt_block	v1, w3, x2, x6, w7
	eor		v2.16b, v2.16b, v1.16b
	encrypt_block	v2, w3, x2, x6, w7
	eor		v3.16b, v3.16b, v2.16b
	encrypt_block	v3, w3, x2, x6, w7
	st1		{v0.16b-v3.16b}, [x0], #64
	mov		v4.16b, v3.16b
	b		.Lcbcencloop4x
.Lcbcenc1x:
	adds		w4, w4, #4
	beq		.Lcbcencout
.Lcbcencloop:
	ld1		{v0.16b}, [x1], #16		/* get next pt block */
	eor		v4.16b, v4.16b, v0.16b		/* ..and xor with iv */
	encrypt_block	v4, w3, x2, x6, w7
	st1		{v4.16b}, [x0], #16
	subs		w4, w4, #1
	bne		.Lcbcencloop
.Lcbcencout:
	st1		{v4.16b}, [x5]			/* return iv */
	ret
AES_FUNC_END(aes_cbc_encrypt)
AES_FUNC_END(aes_essiv_cbc_encrypt)

AES_FUNC_START(aes_essiv_cbc_decrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	ld1		{cbciv.16b}, [x5]		/* get iv */

	mov		w8, #14				/* AES-256: 14 rounds */
	enc_prepare	w8, x6, x7
	encrypt_block	cbciv, w8, x6, x7, w9
	b		.Lessivcbcdecstart

AES_FUNC_START(aes_cbc_decrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	ld1		{cbciv.16b}, [x5]		/* get iv */
.Lessivcbcdecstart:
	dec_prepare	w3, x2, x6

.LcbcdecloopNx:
	subs		w4, w4, #MAX_STRIDE
	bmi		.Lcbcdec1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 ct blocks */
#if MAX_STRIDE == 5
	ld1		{v4.16b}, [x1], #16		/* get 1 ct block */
	mov		v5.16b, v0.16b
	mov		v6.16b, v1.16b
	mov		v7.16b, v2.16b
	bl		aes_decrypt_block5x
	sub		x1, x1, #32
	eor		v0.16b, v0.16b, cbciv.16b
	eor		v1.16b, v1.16b, v5.16b
	ld1		{v5.16b}, [x1], #16		/* reload 1 ct block */
	ld1		{cbciv.16b}, [x1], #16		/* reload 1 ct block */
	eor		v2.16b, v2.16b, v6.16b
	eor		v3.16b, v3.16b, v7.16b
	eor		v4.16b, v4.16b, v5.16b
#else
	mov		v4.16b, v0.16b
	mov		v5.16b, v1.16b
	mov		v6.16b, v2.16b
	bl		aes_decrypt_block4x
	sub		x1, x1, #16
	eor		v0.16b, v0.16b, cbciv.16b
	eor		v1.16b, v1.16b, v4.16b
	ld1		{cbciv.16b}, [x1], #16		/* reload 1 ct block */
	eor		v2.16b, v2.16b, v5.16b
	eor		v3.16b, v3.16b, v6.16b
#endif
	st1		{v0.16b-v3.16b}, [x0], #64
ST5(	st1		{v4.16b}, [x0], #16		)
	b		.LcbcdecloopNx
.Lcbcdec1x:
	adds		w4, w4, #MAX_STRIDE
	beq		.Lcbcdecout
.Lcbcdecloop:
	ld1		{v1.16b}, [x1], #16		/* get next ct block */
	mov		v0.16b, v1.16b			/* ...and copy to v0 */
	decrypt_block	v0, w3, x2, x6, w7
	eor		v0.16b, v0.16b, cbciv.16b	/* xor with iv => pt */
	mov		cbciv.16b, v1.16b		/* ct is next iv */
	st1		{v0.16b}, [x0], #16
	subs		w4, w4, #1
	bne		.Lcbcdecloop
.Lcbcdecout:
	st1		{cbciv.16b}, [x5]		/* return iv */
	ldp		x29, x30, [sp], #16
	ret
AES_FUNC_END(aes_cbc_decrypt)
AES_FUNC_END(aes_essiv_cbc_decrypt)


	/*
	 * aes_cbc_cts_encrypt(u8 out[], u8 const in[], u32 const rk[],
	 *		       int rounds, int bytes, u8 const iv[])
	 * aes_cbc_cts_decrypt(u8 out[], u8 const in[], u32 const rk[],
	 *		       int rounds, int bytes, u8 const iv[])
	 */

AES_FUNC_START(aes_cbc_cts_encrypt)
	adr_l		x8, .Lcts_permute_table
	sub		x4, x4, #16
	add		x9, x8, #32
	add		x8, x8, x4
	sub		x9, x9, x4
	ld1		{v3.16b}, [x8]
	ld1		{v4.16b}, [x9]

	ld1		{v0.16b}, [x1], x4		/* overlapping loads */
	ld1		{v1.16b}, [x1]

	ld1		{v5.16b}, [x5]			/* get iv */
	enc_prepare	w3, x2, x6

	eor		v0.16b, v0.16b, v5.16b		/* xor with iv */
	tbl		v1.16b, {v1.16b}, v4.16b
	encrypt_block	v0, w3, x2, x6, w7

	eor		v1.16b, v1.16b, v0.16b
	tbl		v0.16b, {v0.16b}, v3.16b
	encrypt_block	v1, w3, x2, x6, w7

	add		x4, x0, x4
	st1		{v0.16b}, [x4]			/* overlapping stores */
	st1		{v1.16b}, [x0]
	ret
AES_FUNC_END(aes_cbc_cts_encrypt)

AES_FUNC_START(aes_cbc_cts_decrypt)
	adr_l		x8, .Lcts_permute_table
	sub		x4, x4, #16
	add		x9, x8, #32
	add		x8, x8, x4
	sub		x9, x9, x4
	ld1		{v3.16b}, [x8]
	ld1		{v4.16b}, [x9]

	ld1		{v0.16b}, [x1], x4		/* overlapping loads */
	ld1		{v1.16b}, [x1]

	ld1		{v5.16b}, [x5]			/* get iv */
	dec_prepare	w3, x2, x6

	decrypt_block	v0, w3, x2, x6, w7
	tbl		v2.16b, {v0.16b}, v3.16b
	eor		v2.16b, v2.16b, v1.16b

	tbx		v0.16b, {v1.16b}, v4.16b
	decrypt_block	v0, w3, x2, x6, w7
	eor		v0.16b, v0.16b, v5.16b		/* xor with iv */

	add		x4, x0, x4
	st1		{v2.16b}, [x4]			/* overlapping stores */
	st1		{v0.16b}, [x0]
	ret
AES_FUNC_END(aes_cbc_cts_decrypt)

	.section	".rodata", "a"
	.align		6
.Lcts_permute_table:
	.byte		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
	.byte		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
	.byte		 0x0,  0x1,  0x2,  0x3,  0x4,  0x5,  0x6,  0x7
	.byte		 0x8,  0x9,  0xa,  0xb,  0xc,  0xd,  0xe,  0xf
	.byte		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
	.byte		0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
	.previous

	/*
	 * This macro generates the code for CTR and XCTR mode.
	 */
.macro ctr_encrypt xctr
	// Arguments
	OUT		.req x0
	IN		.req x1
	KEY		.req x2
	ROUNDS_W	.req w3
	BYTES_W		.req w4
	IV		.req x5
	BYTE_CTR_W 	.req w6		// XCTR only
	// Intermediate values
	CTR_W		.req w11	// XCTR only
	CTR		.req x11	// XCTR only
	IV_PART		.req x12
	BLOCKS		.req x13
	BLOCKS_W	.req w13

	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	enc_prepare	ROUNDS_W, KEY, IV_PART
	ld1		{vctr.16b}, [IV]

	/*
	 * Keep 64 bits of the IV in a register.  For CTR mode this lets us
	 * easily increment the IV.  For XCTR mode this lets us efficiently XOR
	 * the 64-bit counter with the IV.
	 */
	.if \xctr
		umov		IV_PART, vctr.d[0]
		lsr		CTR_W, BYTE_CTR_W, #4
	.else
		umov		IV_PART, vctr.d[1]
		rev		IV_PART, IV_PART
	.endif

.LctrloopNx\xctr:
	add		BLOCKS_W, BYTES_W, #15
	sub		BYTES_W, BYTES_W, #MAX_STRIDE << 4
	lsr		BLOCKS_W, BLOCKS_W, #4
	mov		w8, #MAX_STRIDE
	cmp		BLOCKS_W, w8
	csel		BLOCKS_W, BLOCKS_W, w8, lt

	/*
	 * Set up the counter values in v0-v{MAX_STRIDE-1}.
	 *
	 * If we are encrypting less than MAX_STRIDE blocks, the tail block
	 * handling code expects the last keystream block to be in
	 * v{MAX_STRIDE-1}.  For example: if encrypting two blocks with
	 * MAX_STRIDE=5, then v3 and v4 should have the next two counter blocks.
	 */
	.if \xctr
		add		CTR, CTR, BLOCKS
	.else
		adds		IV_PART, IV_PART, BLOCKS
	.endif
	mov		v0.16b, vctr.16b
	mov		v1.16b, vctr.16b
	mov		v2.16b, vctr.16b
	mov		v3.16b, vctr.16b
ST5(	mov		v4.16b, vctr.16b		)
	.if \xctr
		sub		x6, CTR, #MAX_STRIDE - 1
		sub		x7, CTR, #MAX_STRIDE - 2
		sub		x8, CTR, #MAX_STRIDE - 3
		sub		x9, CTR, #MAX_STRIDE - 4
ST5(		sub		x10, CTR, #MAX_STRIDE - 5	)
		eor		x6, x6, IV_PART
		eor		x7, x7, IV_PART
		eor		x8, x8, IV_PART
		eor		x9, x9, IV_PART
ST5(		eor		x10, x10, IV_PART		)
		mov		v0.d[0], x6
		mov		v1.d[0], x7
		mov		v2.d[0], x8
		mov		v3.d[0], x9
ST5(		mov		v4.d[0], x10			)
	.else
		bcs		0f
		.subsection	1
		/*
		 * This subsection handles carries.
		 *
		 * Conditional branching here is allowed with respect to time
		 * invariance since the branches are dependent on the IV instead
		 * of the plaintext or key.  This code is rarely executed in
		 * practice anyway.
		 */

		/* Apply carry to outgoing counter. */
0:		umov		x8, vctr.d[0]
		rev		x8, x8
		add		x8, x8, #1
		rev		x8, x8
		ins		vctr.d[0], x8

		/*
		 * Apply carry to counter blocks if needed.
		 *
		 * Since the carry flag was set, we know 0 <= IV_PART <
		 * MAX_STRIDE.  Using the value of IV_PART we can determine how
		 * many counter blocks need to be updated.
		 */
		cbz		IV_PART, 2f
		adr		x16, 1f
		sub		x16, x16, IV_PART, lsl #3
		br		x16
		bti		c
		mov		v0.d[0], vctr.d[0]
		bti		c
		mov		v1.d[0], vctr.d[0]
		bti		c
		mov		v2.d[0], vctr.d[0]
		bti		c
		mov		v3.d[0], vctr.d[0]
ST5(		bti		c				)
ST5(		mov		v4.d[0], vctr.d[0]		)
1:		b		2f
		.previous

2:		rev		x7, IV_PART
		ins		vctr.d[1], x7
		sub		x7, IV_PART, #MAX_STRIDE - 1
		sub		x8, IV_PART, #MAX_STRIDE - 2
		sub		x9, IV_PART, #MAX_STRIDE - 3
		rev		x7, x7
		rev		x8, x8
		mov		v1.d[1], x7
		rev		x9, x9
ST5(		sub		x10, IV_PART, #MAX_STRIDE - 4	)
		mov		v2.d[1], x8
ST5(		rev		x10, x10			)
		mov		v3.d[1], x9
ST5(		mov		v4.d[1], x10			)
	.endif

	/*
	 * If there are at least MAX_STRIDE blocks left, XOR the data with
	 * keystream and store.  Otherwise jump to tail handling.
	 */
	tbnz		BYTES_W, #31, .Lctrtail\xctr
	ld1		{v5.16b-v7.16b}, [IN], #48
ST4(	bl		aes_encrypt_block4x		)
ST5(	bl		aes_encrypt_block5x		)
	eor		v0.16b, v5.16b, v0.16b
ST4(	ld1		{v5.16b}, [IN], #16		)
	eor		v1.16b, v6.16b, v1.16b
ST5(	ld1		{v5.16b-v6.16b}, [IN], #32	)
	eor		v2.16b, v7.16b, v2.16b
	eor		v3.16b, v5.16b, v3.16b
ST5(	eor		v4.16b, v6.16b, v4.16b		)
	st1		{v0.16b-v3.16b}, [OUT], #64
ST5(	st1		{v4.16b}, [OUT], #16		)
	cbz		BYTES_W, .Lctrout\xctr
	b		.LctrloopNx\xctr

.Lctrout\xctr:
	.if !\xctr
		st1		{vctr.16b}, [IV] /* return next CTR value */
	.endif
	ldp		x29, x30, [sp], #16
	ret

.Lctrtail\xctr:
	/*
	 * Handle up to MAX_STRIDE * 16 - 1 bytes of plaintext
	 *
	 * This code expects the last keystream block to be in v{MAX_STRIDE-1}.
	 * For example: if encrypting two blocks with MAX_STRIDE=5, then v3 and
	 * v4 should have the next two counter blocks.
	 *
	 * This allows us to store the ciphertext by writing to overlapping
	 * regions of memory.  Any invalid ciphertext blocks get overwritten by
	 * correctly computed blocks.  This approach greatly simplifies the
	 * logic for storing the ciphertext.
	 */
	mov		x16, #16
	ands		w7, BYTES_W, #0xf
	csel		x13, x7, x16, ne

ST5(	cmp		BYTES_W, #64 - (MAX_STRIDE << 4))
ST5(	csel		x14, x16, xzr, gt		)
	cmp		BYTES_W, #48 - (MAX_STRIDE << 4)
	csel		x15, x16, xzr, gt
	cmp		BYTES_W, #32 - (MAX_STRIDE << 4)
	csel		x16, x16, xzr, gt
	cmp		BYTES_W, #16 - (MAX_STRIDE << 4)

	adr_l		x9, .Lcts_permute_table
	add		x9, x9, x13
	ble		.Lctrtail1x\xctr

ST5(	ld1		{v5.16b}, [IN], x14		)
	ld1		{v6.16b}, [IN], x15
	ld1		{v7.16b}, [IN], x16

ST4(	bl		aes_encrypt_block4x		)
ST5(	bl		aes_encrypt_block5x		)

	ld1		{v8.16b}, [IN], x13
	ld1		{v9.16b}, [IN]
	ld1		{v10.16b}, [x9]

ST4(	eor		v6.16b, v6.16b, v0.16b		)
ST4(	eor		v7.16b, v7.16b, v1.16b		)
ST4(	tbl		v3.16b, {v3.16b}, v10.16b	)
ST4(	eor		v8.16b, v8.16b, v2.16b		)
ST4(	eor		v9.16b, v9.16b, v3.16b		)

ST5(	eor		v5.16b, v5.16b, v0.16b		)
ST5(	eor		v6.16b, v6.16b, v1.16b		)
ST5(	tbl		v4.16b, {v4.16b}, v10.16b	)
ST5(	eor		v7.16b, v7.16b, v2.16b		)
ST5(	eor		v8.16b, v8.16b, v3.16b		)
ST5(	eor		v9.16b, v9.16b, v4.16b		)

ST5(	st1		{v5.16b}, [OUT], x14		)
	st1		{v6.16b}, [OUT], x15
	st1		{v7.16b}, [OUT], x16
	add		x13, x13, OUT
	st1		{v9.16b}, [x13]		// overlapping stores
	st1		{v8.16b}, [OUT]
	b		.Lctrout\xctr

.Lctrtail1x\xctr:
	/*
	 * Handle <= 16 bytes of plaintext
	 *
	 * This code always reads and writes 16 bytes.  To avoid out of bounds
	 * accesses, XCTR and CTR modes must use a temporary buffer when
	 * encrypting/decrypting less than 16 bytes.
	 *
	 * This code is unusual in that it loads the input and stores the output
	 * relative to the end of the buffers rather than relative to the start.
	 * This causes unusual behaviour when encrypting/decrypting less than 16
	 * bytes; the end of the data is expected to be at the end of the
	 * temporary buffer rather than the start of the data being at the start
	 * of the temporary buffer.
	 */
	sub		x8, x7, #16
	csel		x7, x7, x8, eq
	add		IN, IN, x7
	add		OUT, OUT, x7
	ld1		{v5.16b}, [IN]
	ld1		{v6.16b}, [OUT]
ST5(	mov		v3.16b, v4.16b			)
	encrypt_block	v3, ROUNDS_W, KEY, x8, w7
	ld1		{v10.16b-v11.16b}, [x9]
	tbl		v3.16b, {v3.16b}, v10.16b
	sshr		v11.16b, v11.16b, #7
	eor		v5.16b, v5.16b, v3.16b
	bif		v5.16b, v6.16b, v11.16b
	st1		{v5.16b}, [OUT]
	b		.Lctrout\xctr

	// Arguments
	.unreq OUT
	.unreq IN
	.unreq KEY
	.unreq ROUNDS_W
	.unreq BYTES_W
	.unreq IV
	.unreq BYTE_CTR_W	// XCTR only
	// Intermediate values
	.unreq CTR_W		// XCTR only
	.unreq CTR		// XCTR only
	.unreq IV_PART
	.unreq BLOCKS
	.unreq BLOCKS_W
.endm

	/*
	 * aes_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int bytes, u8 ctr[])
	 *
	 * The input and output buffers must always be at least 16 bytes even if
	 * encrypting/decrypting less than 16 bytes.  Otherwise out of bounds
	 * accesses will occur.  The data to be encrypted/decrypted is expected
	 * to be at the end of this 16-byte temporary buffer rather than the
	 * start.
	 */

AES_FUNC_START(aes_ctr_encrypt)
	ctr_encrypt 0
AES_FUNC_END(aes_ctr_encrypt)

	/*
	 * aes_xctr_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
	 *		   int bytes, u8 const iv[], int byte_ctr)
	 *
	 * The input and output buffers must always be at least 16 bytes even if
	 * encrypting/decrypting less than 16 bytes.  Otherwise out of bounds
	 * accesses will occur.  The data to be encrypted/decrypted is expected
	 * to be at the end of this 16-byte temporary buffer rather than the
	 * start.
	 */

AES_FUNC_START(aes_xctr_encrypt)
	ctr_encrypt 1
AES_FUNC_END(aes_xctr_encrypt)


	/*
	 * aes_xts_encrypt(u8 out[], u8 const in[], u8 const rk1[], int rounds,
	 *		   int bytes, u8 const rk2[], u8 iv[], int first)
	 * aes_xts_decrypt(u8 out[], u8 const in[], u8 const rk1[], int rounds,
	 *		   int bytes, u8 const rk2[], u8 iv[], int first)
	 */

	.macro		next_tweak, out, in, tmp
	sshr		\tmp\().2d,  \in\().2d,   #63
	and		\tmp\().16b, \tmp\().16b, xtsmask.16b
	add		\out\().2d,  \in\().2d,   \in\().2d
	ext		\tmp\().16b, \tmp\().16b, \tmp\().16b, #8
	eor		\out\().16b, \out\().16b, \tmp\().16b
	.endm

	.macro		xts_load_mask, tmp
	movi		xtsmask.2s, #0x1
	movi		\tmp\().2s, #0x87
	uzp1		xtsmask.4s, xtsmask.4s, \tmp\().4s
	.endm

AES_FUNC_START(aes_xts_encrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	ld1		{v4.16b}, [x6]
	xts_load_mask	v8
	cbz		w7, .Lxtsencnotfirst

	enc_prepare	w3, x5, x8
	xts_cts_skip_tw	w7, .LxtsencNx
	encrypt_block	v4, w3, x5, x8, w7		/* first tweak */
	enc_switch_key	w3, x2, x8
	b		.LxtsencNx

.Lxtsencnotfirst:
	enc_prepare	w3, x2, x8
.LxtsencloopNx:
	next_tweak	v4, v4, v8
.LxtsencNx:
	subs		w4, w4, #64
	bmi		.Lxtsenc1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 pt blocks */
	next_tweak	v5, v4, v8
	eor		v0.16b, v0.16b, v4.16b
	next_tweak	v6, v5, v8
	eor		v1.16b, v1.16b, v5.16b
	eor		v2.16b, v2.16b, v6.16b
	next_tweak	v7, v6, v8
	eor		v3.16b, v3.16b, v7.16b
	bl		aes_encrypt_block4x
	eor		v3.16b, v3.16b, v7.16b
	eor		v0.16b, v0.16b, v4.16b
	eor		v1.16b, v1.16b, v5.16b
	eor		v2.16b, v2.16b, v6.16b
	st1		{v0.16b-v3.16b}, [x0], #64
	mov		v4.16b, v7.16b
	cbz		w4, .Lxtsencret
	xts_reload_mask	v8
	b		.LxtsencloopNx
.Lxtsenc1x:
	adds		w4, w4, #64
	beq		.Lxtsencout
	subs		w4, w4, #16
	bmi		.LxtsencctsNx
.Lxtsencloop:
	ld1		{v0.16b}, [x1], #16
.Lxtsencctsout:
	eor		v0.16b, v0.16b, v4.16b
	encrypt_block	v0, w3, x2, x8, w7
	eor		v0.16b, v0.16b, v4.16b
	cbz		w4, .Lxtsencout
	subs		w4, w4, #16
	next_tweak	v4, v4, v8
	bmi		.Lxtsenccts
	st1		{v0.16b}, [x0], #16
	b		.Lxtsencloop
.Lxtsencout:
	st1		{v0.16b}, [x0]
.Lxtsencret:
	st1		{v4.16b}, [x6]
	ldp		x29, x30, [sp], #16
	ret

.LxtsencctsNx:
	mov		v0.16b, v3.16b
	sub		x0, x0, #16
.Lxtsenccts:
	adr_l		x8, .Lcts_permute_table

	add		x1, x1, w4, sxtw	/* rewind input pointer */
	add		w4, w4, #16		/* # bytes in final block */
	add		x9, x8, #32
	add		x8, x8, x4
	sub		x9, x9, x4
	add		x4, x0, x4		/* output address of final block */

	ld1		{v1.16b}, [x1]		/* load final block */
	ld1		{v2.16b}, [x8]
	ld1		{v3.16b}, [x9]

	tbl		v2.16b, {v0.16b}, v2.16b
	tbx		v0.16b, {v1.16b}, v3.16b
	st1		{v2.16b}, [x4]			/* overlapping stores */
	mov		w4, wzr
	b		.Lxtsencctsout
AES_FUNC_END(aes_xts_encrypt)

AES_FUNC_START(aes_xts_decrypt)
	stp		x29, x30, [sp, #-16]!
	mov		x29, sp

	/* subtract 16 bytes if we are doing CTS */
	sub		w8, w4, #0x10
	tst		w4, #0xf
	csel		w4, w4, w8, eq

	ld1		{v4.16b}, [x6]
	xts_load_mask	v8
	xts_cts_skip_tw	w7, .Lxtsdecskiptw
	cbz		w7, .Lxtsdecnotfirst

	enc_prepare	w3, x5, x8
	encrypt_block	v4, w3, x5, x8, w7		/* first tweak */
.Lxtsdecskiptw:
	dec_prepare	w3, x2, x8
	b		.LxtsdecNx

.Lxtsdecnotfirst:
	dec_prepare	w3, x2, x8
.LxtsdecloopNx:
	next_tweak	v4, v4, v8
.LxtsdecNx:
	subs		w4, w4, #64
	bmi		.Lxtsdec1x
	ld1		{v0.16b-v3.16b}, [x1], #64	/* get 4 ct blocks */
	next_tweak	v5, v4, v8
	eor		v0.16b, v0.16b, v4.16b
	next_tweak	v6, v5, v8
	eor		v1.16b, v1.16b, v5.16b
	eor		v2.16b, v2.16b, v6.16b
	next_tweak	v7, v6, v8
	eor		v3.16b, v3.16b, v7.16b
	bl		aes_decrypt_block4x
	eor		v3.16b, v3.16b, v7.16b
	eor		v0.16b, v0.16b, v4.16b
	eor		v1.16b, v1.16b, v5.16b
	eor		v2.16b, v2.16b, v6.16b
	st1		{v0.16b-v3.16b}, [x0], #64
	mov		v4.16b, v7.16b
	cbz		w4, .Lxtsdecout
	xts_reload_mask	v8
	b		.LxtsdecloopNx
.Lxtsdec1x:
	adds		w4, w4, #64
	beq		.Lxtsdecout
	subs		w4, w4, #16
.Lxtsdecloop:
	ld1		{v0.16b}, [x1], #16
	bmi		.Lxtsdeccts
.Lxtsdecctsout:
	eor		v0.16b, v0.16b, v4.16b
	decrypt_block	v0, w3, x2, x8, w7
	eor		v0.16b, v0.16b, v4.16b
	st1		{v0.16b}, [x0], #16
	cbz		w4, .Lxtsdecout
	subs		w4, w4, #16
	next_tweak	v4, v4, v8
	b		.Lxtsdecloop
.Lxtsdecout:
	st1		{v4.16b}, [x6]
	ldp		x29, x30, [sp], #16
	ret

.Lxtsdeccts:
	adr_l		x8, .Lcts_permute_table

	add		x1, x1, w4, sxtw	/* rewind input pointer */
	add		w4, w4, #16		/* # bytes in final block */
	add		x9, x8, #32
	add		x8, x8, x4
	sub		x9, x9, x4
	add		x4, x0, x4		/* output address of final block */

	next_tweak	v5, v4, v8

	ld1		{v1.16b}, [x1]		/* load final block */
	ld1		{v2.16b}, [x8]
	ld1		{v3.16b}, [x9]

	eor		v0.16b, v0.16b, v5.16b
	decrypt_block	v0, w3, x2, x8, w7
	eor		v0.16b, v0.16b, v5.16b

	tbl		v2.16b, {v0.16b}, v2.16b
	tbx		v0.16b, {v1.16b}, v3.16b

	st1		{v2.16b}, [x4]			/* overlapping stores */
	mov		w4, wzr
	b		.Lxtsdecctsout
AES_FUNC_END(aes_xts_decrypt)

	/*
	 * aes_mac_update(u8 const in[], u32 const rk[], int rounds,
	 *		  int blocks, u8 dg[], int enc_before, int enc_after)
	 */
AES_FUNC_START(aes_mac_update)
	ld1		{v0.16b}, [x4]			/* get dg */
	enc_prepare	w2, x1, x7
	cbz		w5, .Lmacloop4x

	encrypt_block	v0, w2, x1, x7, w8

.Lmacloop4x:
	subs		w3, w3, #4
	bmi		.Lmac1x
	ld1		{v1.16b-v4.16b}, [x0], #64	/* get next pt block */
	eor		v0.16b, v0.16b, v1.16b		/* ..and xor with dg */
	encrypt_block	v0, w2, x1, x7, w8
	eor		v0.16b, v0.16b, v2.16b
	encrypt_block	v0, w2, x1, x7, w8
	eor		v0.16b, v0.16b, v3.16b
	encrypt_block	v0, w2, x1, x7, w8
	eor		v0.16b, v0.16b, v4.16b
	cmp		w3, wzr
	csinv		x5, x6, xzr, eq
	cbz		w5, .Lmacout
	encrypt_block	v0, w2, x1, x7, w8
	st1		{v0.16b}, [x4]			/* return dg */
	cond_yield	.Lmacout, x7, x8
	b		.Lmacloop4x
.Lmac1x:
	add		w3, w3, #4
.Lmacloop:
	cbz		w3, .Lmacout
	ld1		{v1.16b}, [x0], #16		/* get next pt block */
	eor		v0.16b, v0.16b, v1.16b		/* ..and xor with dg */

	subs		w3, w3, #1
	csinv		x5, x6, xzr, eq
	cbz		w5, .Lmacout

.Lmacenc:
	encrypt_block	v0, w2, x1, x7, w8
	b		.Lmacloop

.Lmacout:
	st1		{v0.16b}, [x4]			/* return dg */
	mov		w0, w3
	ret
AES_FUNC_END(aes_mac_update)