summaryrefslogtreecommitdiff
path: root/drivers/tty/vt/vt_ioctl.c
blob: 91c3017750476d73ec9b193b9b8a7fe1995624fe (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
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1992 obz under the linux copyright
 *
 *  Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
 *  Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
 *  Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
 *  Some code moved for less code duplication - Andi Kleen - Mar 1997
 *  Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/tty.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/kd.h>
#include <linux/vt.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/console.h>
#include <linux/consolemap.h>
#include <linux/signal.h>
#include <linux/suspend.h>
#include <linux/timex.h>

#include <asm/io.h>
#include <linux/uaccess.h>

#include <linux/nospec.h>

#include <linux/kbd_kern.h>
#include <linux/vt_kern.h>
#include <linux/kbd_diacr.h>
#include <linux/selection.h>

bool vt_dont_switch;

static inline bool vt_in_use(unsigned int i)
{
	const struct vc_data *vc = vc_cons[i].d;

	/*
	 * console_lock must be held to prevent the vc from being deallocated
	 * while we're checking whether it's in-use.
	 */
	WARN_CONSOLE_UNLOCKED();

	return vc && kref_read(&vc->port.kref) > 1;
}

static inline bool vt_busy(int i)
{
	if (vt_in_use(i))
		return true;
	if (i == fg_console)
		return true;
	if (vc_is_sel(vc_cons[i].d))
		return true;

	return false;
}

/*
 * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
 * experimentation and study of X386 SYSV handling.
 *
 * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
 * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
 * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
 * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
 * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
 * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
 * to the current console is done by the main ioctl code.
 */

#ifdef CONFIG_X86
#include <asm/syscalls.h>
#endif

static void complete_change_console(struct vc_data *vc);

/*
 *	User space VT_EVENT handlers
 */

struct vt_event_wait {
	struct list_head list;
	struct vt_event event;
	int done;
};

static LIST_HEAD(vt_events);
static DEFINE_SPINLOCK(vt_event_lock);
static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);

/**
 *	vt_event_post
 *	@event: the event that occurred
 *	@old: old console
 *	@new: new console
 *
 *	Post an VT event to interested VT handlers
 */

void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
{
	struct list_head *pos, *head;
	unsigned long flags;
	int wake = 0;

	spin_lock_irqsave(&vt_event_lock, flags);
	head = &vt_events;

	list_for_each(pos, head) {
		struct vt_event_wait *ve = list_entry(pos,
						struct vt_event_wait, list);
		if (!(ve->event.event & event))
			continue;
		ve->event.event = event;
		/* kernel view is consoles 0..n-1, user space view is
		   console 1..n with 0 meaning current, so we must bias */
		ve->event.oldev = old + 1;
		ve->event.newev = new + 1;
		wake = 1;
		ve->done = 1;
	}
	spin_unlock_irqrestore(&vt_event_lock, flags);
	if (wake)
		wake_up_interruptible(&vt_event_waitqueue);
}

static void __vt_event_queue(struct vt_event_wait *vw)
{
	unsigned long flags;
	/* Prepare the event */
	INIT_LIST_HEAD(&vw->list);
	vw->done = 0;
	/* Queue our event */
	spin_lock_irqsave(&vt_event_lock, flags);
	list_add(&vw->list, &vt_events);
	spin_unlock_irqrestore(&vt_event_lock, flags);
}

static void __vt_event_wait(struct vt_event_wait *vw)
{
	/* Wait for it to pass */
	wait_event_interruptible(vt_event_waitqueue, vw->done);
}

static void __vt_event_dequeue(struct vt_event_wait *vw)
{
	unsigned long flags;

	/* Dequeue it */
	spin_lock_irqsave(&vt_event_lock, flags);
	list_del(&vw->list);
	spin_unlock_irqrestore(&vt_event_lock, flags);
}

/**
 *	vt_event_wait		-	wait for an event
 *	@vw: our event
 *
 *	Waits for an event to occur which completes our vt_event_wait
 *	structure. On return the structure has wv->done set to 1 for success
 *	or 0 if some event such as a signal ended the wait.
 */

static void vt_event_wait(struct vt_event_wait *vw)
{
	__vt_event_queue(vw);
	__vt_event_wait(vw);
	__vt_event_dequeue(vw);
}

/**
 *	vt_event_wait_ioctl	-	event ioctl handler
 *	@arg: argument to ioctl
 *
 *	Implement the VT_WAITEVENT ioctl using the VT event interface
 */

static int vt_event_wait_ioctl(struct vt_event __user *event)
{
	struct vt_event_wait vw;

	if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
		return -EFAULT;
	/* Highest supported event for now */
	if (vw.event.event & ~VT_MAX_EVENT)
		return -EINVAL;

	vt_event_wait(&vw);
	/* If it occurred report it */
	if (vw.done) {
		if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
			return -EFAULT;
		return 0;
	}
	return -EINTR;
}

/**
 *	vt_waitactive	-	active console wait
 *	@event: event code
 *	@n: new console
 *
 *	Helper for event waits. Used to implement the legacy
 *	event waiting ioctls in terms of events
 */

int vt_waitactive(int n)
{
	struct vt_event_wait vw;
	do {
		vw.event.event = VT_EVENT_SWITCH;
		__vt_event_queue(&vw);
		if (n == fg_console + 1) {
			__vt_event_dequeue(&vw);
			break;
		}
		__vt_event_wait(&vw);
		__vt_event_dequeue(&vw);
		if (vw.done == 0)
			return -EINTR;
	} while (vw.event.newev != n);
	return 0;
}

/*
 * these are the valid i/o ports we're allowed to change. they map all the
 * video ports
 */
#define GPFIRST 0x3b4
#define GPLAST 0x3df
#define GPNUM (GPLAST - GPFIRST + 1)

/*
 * currently, setting the mode from KD_TEXT to KD_GRAPHICS doesn't do a whole
 * lot. i'm not sure if it should do any restoration of modes or what...
 *
 * XXX It should at least call into the driver, fbdev's definitely need to
 * restore their engine state. --BenH
 */
static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
{
	switch (mode) {
	case KD_GRAPHICS:
		break;
	case KD_TEXT0:
	case KD_TEXT1:
		mode = KD_TEXT;
		fallthrough;
	case KD_TEXT:
		break;
	default:
		return -EINVAL;
	}

	/* FIXME: this needs the console lock extending */
	if (vc->vc_mode == mode)
		return 0;

	vc->vc_mode = mode;
	if (vc->vc_num != fg_console)
		return 0;

	/* explicitly blank/unblank the screen if switching modes */
	console_lock();
	if (mode == KD_TEXT)
		do_unblank_screen(1);
	else
		do_blank_screen(1);
	console_unlock();

	return 0;
}

static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
		unsigned long arg, bool perm)
{
	struct vc_data *vc = tty->driver_data;
	void __user *up = (void __user *)arg;
	unsigned int console = vc->vc_num;
	int ret;

	switch (cmd) {
	case KIOCSOUND:
		if (!perm)
			return -EPERM;
		/*
		 * The use of PIT_TICK_RATE is historic, it used to be
		 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
		 * and 2.6.36, which was a minor but unfortunate ABI
		 * change. kd_mksound is locked by the input layer.
		 */
		if (arg)
			arg = PIT_TICK_RATE / arg;
		kd_mksound(arg, 0);
		break;

	case KDMKTONE:
		if (!perm)
			return -EPERM;
	{
		unsigned int ticks, count;

		/*
		 * Generate the tone for the appropriate number of ticks.
		 * If the time is zero, turn off sound ourselves.
		 */
		ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
		count = ticks ? (arg & 0xffff) : 0;
		if (count)
			count = PIT_TICK_RATE / count;
		kd_mksound(count, ticks);
		break;
	}

	case KDGKBTYPE:
		/*
		 * this is naïve.
		 */
		return put_user(KB_101, (char __user *)arg);

		/*
		 * These cannot be implemented on any machine that implements
		 * ioperm() in user level (such as Alpha PCs) or not at all.
		 *
		 * XXX: you should never use these, just call ioperm directly..
		 */
#ifdef CONFIG_X86
	case KDADDIO:
	case KDDELIO:
		/*
		 * KDADDIO and KDDELIO may be able to add ports beyond what
		 * we reject here, but to be safe...
		 *
		 * These are locked internally via sys_ioperm
		 */
		if (arg < GPFIRST || arg > GPLAST)
			return -EINVAL;

		return ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;

	case KDENABIO:
	case KDDISABIO:
		return ksys_ioperm(GPFIRST, GPNUM,
				  (cmd == KDENABIO)) ? -ENXIO : 0;
#endif

	/* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */

	case KDKBDREP:
	{
		struct kbd_repeat kbrep;

		if (!capable(CAP_SYS_TTY_CONFIG))
			return -EPERM;

		if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
			return -EFAULT;

		ret = kbd_rate(&kbrep);
		if (ret)
			return ret;
		if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
			return -EFAULT;
		break;
	}

	case KDSETMODE:
		if (!perm)
			return -EPERM;

		return vt_kdsetmode(vc, arg);

	case KDGETMODE:
		return put_user(vc->vc_mode, (int __user *)arg);

	case KDMAPDISP:
	case KDUNMAPDISP:
		/*
		 * these work like a combination of mmap and KDENABIO.
		 * this could be easily finished.
		 */
		return -EINVAL;

	case KDSKBMODE:
		if (!perm)
			return -EPERM;
		ret = vt_do_kdskbmode(console, arg);
		if (ret)
			return ret;
		tty_ldisc_flush(tty);
		break;

	case KDGKBMODE:
		return put_user(vt_do_kdgkbmode(console), (int __user *)arg);

	/* this could be folded into KDSKBMODE, but for compatibility
	   reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
	case KDSKBMETA:
		return vt_do_kdskbmeta(console, arg);

	case KDGKBMETA:
		/* FIXME: should review whether this is worth locking */
		return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);

	case KDGETKEYCODE:
	case KDSETKEYCODE:
		if(!capable(CAP_SYS_TTY_CONFIG))
			perm = 0;
		return vt_do_kbkeycode_ioctl(cmd, up, perm);

	case KDGKBENT:
	case KDSKBENT:
		return vt_do_kdsk_ioctl(cmd, up, perm, console);

	case KDGKBSENT:
	case KDSKBSENT:
		return vt_do_kdgkb_ioctl(cmd, up, perm);

	/* Diacritical processing. Handled in keyboard.c as it has
	   to operate on the keyboard locks and structures */
	case KDGKBDIACR:
	case KDGKBDIACRUC:
	case KDSKBDIACR:
	case KDSKBDIACRUC:
		return vt_do_diacrit(cmd, up, perm);

	/* the ioctls below read/set the flags usually shown in the leds */
	/* don't use them - they will go away without warning */
	case KDGKBLED:
	case KDSKBLED:
	case KDGETLED:
	case KDSETLED:
		return vt_do_kdskled(console, cmd, arg, perm);

	/*
	 * A process can indicate its willingness to accept signals
	 * generated by pressing an appropriate key combination.
	 * Thus, one can have a daemon that e.g. spawns a new console
	 * upon a keypress and then changes to it.
	 * See also the kbrequest field of inittab(5).
	 */
	case KDSIGACCEPT:
		if (!perm || !capable(CAP_KILL))
			return -EPERM;
		if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
			return -EINVAL;

		spin_lock_irq(&vt_spawn_con.lock);
		put_pid(vt_spawn_con.pid);
		vt_spawn_con.pid = get_pid(task_pid(current));
		vt_spawn_con.sig = arg;
		spin_unlock_irq(&vt_spawn_con.lock);
		break;

	case KDFONTOP: {
		struct console_font_op op;

		if (copy_from_user(&op, up, sizeof(op)))
			return -EFAULT;
		if (!perm && op.op != KD_FONT_OP_GET)
			return -EPERM;
		ret = con_font_op(vc, &op);
		if (ret)
			return ret;
		if (copy_to_user(up, &op, sizeof(op)))
			return -EFAULT;
		break;
	}

	default:
		return -ENOIOCTLCMD;
	}

	return 0;
}

static inline int do_fontx_ioctl(int cmd,
		struct consolefontdesc __user *user_cfd,
		struct console_font_op *op)
{
	struct consolefontdesc cfdarg;
	int i;

	if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
		return -EFAULT;

	switch (cmd) {
	case PIO_FONTX:
		op->op = KD_FONT_OP_SET;
		op->flags = KD_FONT_FLAG_OLD;
		op->width = 8;
		op->height = cfdarg.charheight;
		op->charcount = cfdarg.charcount;
		op->data = cfdarg.chardata;
		return con_font_op(vc_cons[fg_console].d, op);
	case GIO_FONTX: {
		op->op = KD_FONT_OP_GET;
		op->flags = KD_FONT_FLAG_OLD;
		op->width = 8;
		op->height = cfdarg.charheight;
		op->charcount = cfdarg.charcount;
		op->data = cfdarg.chardata;
		i = con_font_op(vc_cons[fg_console].d, op);
		if (i)
			return i;
		cfdarg.charheight = op->height;
		cfdarg.charcount = op->charcount;
		if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
			return -EFAULT;
		return 0;
		}
	}
	return -EINVAL;
}

static int vt_io_fontreset(struct console_font_op *op)
{
	int ret;

	if (__is_defined(BROKEN_GRAPHICS_PROGRAMS)) {
		/*
		 * With BROKEN_GRAPHICS_PROGRAMS defined, the default font is
		 * not saved.
		 */
		return -ENOSYS;
	}

	op->op = KD_FONT_OP_SET_DEFAULT;
	op->data = NULL;
	ret = con_font_op(vc_cons[fg_console].d, op);
	if (ret)
		return ret;

	console_lock();
	con_set_default_unimap(vc_cons[fg_console].d);
	console_unlock();

	return 0;
}

static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
		struct vc_data *vc)
{
	struct unimapdesc tmp;

	if (copy_from_user(&tmp, user_ud, sizeof tmp))
		return -EFAULT;
	switch (cmd) {
	case PIO_UNIMAP:
		return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
	case GIO_UNIMAP:
		if (fg_console != vc->vc_num)
			return -EPERM;
		return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
				tmp.entries);
	}
	return 0;
}

static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
		bool perm)
{
	struct console_font_op op;	/* used in multiple places here */

	switch (cmd) {
	case PIO_FONT:
		if (!perm)
			return -EPERM;
		op.op = KD_FONT_OP_SET;
		op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC;	/* Compatibility */
		op.width = 8;
		op.height = 0;
		op.charcount = 256;
		op.data = up;
		return con_font_op(vc_cons[fg_console].d, &op);

	case GIO_FONT:
		op.op = KD_FONT_OP_GET;
		op.flags = KD_FONT_FLAG_OLD;
		op.width = 8;
		op.height = 32;
		op.charcount = 256;
		op.data = up;
		return con_font_op(vc_cons[fg_console].d, &op);

	case PIO_CMAP:
                if (!perm)
			return -EPERM;
		return con_set_cmap(up);

	case GIO_CMAP:
                return con_get_cmap(up);

	case PIO_FONTX:
		if (!perm)
			return -EPERM;

		fallthrough;
	case GIO_FONTX:
		return do_fontx_ioctl(cmd, up, &op);

	case PIO_FONTRESET:
		if (!perm)
			return -EPERM;

		return vt_io_fontreset(&op);

	case PIO_SCRNMAP:
		if (!perm)
			return -EPERM;
		return con_set_trans_old(up);

	case GIO_SCRNMAP:
		return con_get_trans_old(up);

	case PIO_UNISCRNMAP:
		if (!perm)
			return -EPERM;
		return con_set_trans_new(up);

	case GIO_UNISCRNMAP:
		return con_get_trans_new(up);

	case PIO_UNIMAPCLR:
		if (!perm)
			return -EPERM;
		con_clear_unimap(vc);
		break;

	case PIO_UNIMAP:
	case GIO_UNIMAP:
		if (!perm)
			return -EPERM;

		return do_unimap_ioctl(cmd, up, vc);

	default:
		return -ENOIOCTLCMD;
	}

	return 0;
}

static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
{
	int newvt, ret;

	if (vc->vt_mode.mode != VT_PROCESS)
		return -EINVAL;

	/* Switched-to response */
	if (vc->vt_newvt < 0) {
		 /* If it's just an ACK, ignore it */
		return swtch == VT_ACKACQ ? 0 : -EINVAL;
	}

	/* Switching-from response */
	if (swtch == 0) {
		/* Switch disallowed, so forget we were trying to do it. */
		vc->vt_newvt = -1;
		return 0;
	}

	/* The current vt has been released, so complete the switch. */
	newvt = vc->vt_newvt;
	vc->vt_newvt = -1;
	ret = vc_allocate(newvt);
	if (ret)
		return ret;

	/*
	 * When we actually do the console switch, make sure we are atomic with
	 * respect to other console switches..
	 */
	complete_change_console(vc_cons[newvt].d);

	return 0;
}

static int vt_setactivate(struct vt_setactivate __user *sa)
{
	struct vt_setactivate vsa;
	struct vc_data *nvc;
	int ret;

	if (copy_from_user(&vsa, sa, sizeof(vsa)))
		return -EFAULT;
	if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
		return -ENXIO;

	vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES + 1);
	vsa.console--;
	console_lock();
	ret = vc_allocate(vsa.console);
	if (ret) {
		console_unlock();
		return ret;
	}

	/*
	 * This is safe providing we don't drop the console sem between
	 * vc_allocate and finishing referencing nvc.
	 */
	nvc = vc_cons[vsa.console].d;
	nvc->vt_mode = vsa.mode;
	nvc->vt_mode.frsig = 0;
	put_pid(nvc->vt_pid);
	nvc->vt_pid = get_pid(task_pid(current));
	console_unlock();

	/* Commence switch and lock */
	/* Review set_console locks */
	set_console(vsa.console);

	return 0;
}

/* deallocate a single console, if possible (leave 0) */
static int vt_disallocate(unsigned int vc_num)
{
	struct vc_data *vc = NULL;
	int ret = 0;

	console_lock();
	if (vt_busy(vc_num))
		ret = -EBUSY;
	else if (vc_num)
		vc = vc_deallocate(vc_num);
	console_unlock();

	if (vc && vc_num >= MIN_NR_CONSOLES)
		tty_port_put(&vc->port);

	return ret;
}

/* deallocate all unused consoles, but leave 0 */
static void vt_disallocate_all(void)
{
	struct vc_data *vc[MAX_NR_CONSOLES];
	int i;

	console_lock();
	for (i = 1; i < MAX_NR_CONSOLES; i++)
		if (!vt_busy(i))
			vc[i] = vc_deallocate(i);
		else
			vc[i] = NULL;
	console_unlock();

	for (i = 1; i < MAX_NR_CONSOLES; i++) {
		if (vc[i] && i >= MIN_NR_CONSOLES)
			tty_port_put(&vc[i]->port);
	}
}

static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
{
	struct vt_consize v;
	int i;

	if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
		return -EFAULT;

	/* FIXME: Should check the copies properly */
	if (!v.v_vlin)
		v.v_vlin = vc->vc_scan_lines;

	if (v.v_clin) {
		int rows = v.v_vlin / v.v_clin;
		if (v.v_rows != rows) {
			if (v.v_rows) /* Parameters don't add up */
				return -EINVAL;
			v.v_rows = rows;
		}
	}

	if (v.v_vcol && v.v_ccol) {
		int cols = v.v_vcol / v.v_ccol;
		if (v.v_cols != cols) {
			if (v.v_cols)
				return -EINVAL;
			v.v_cols = cols;
		}
	}

	if (v.v_clin > 32)
		return -EINVAL;

	for (i = 0; i < MAX_NR_CONSOLES; i++) {
		struct vc_data *vcp;

		if (!vc_cons[i].d)
			continue;
		console_lock();
		vcp = vc_cons[i].d;
		if (vcp) {
			if (v.v_vlin)
				vcp->vc_scan_lines = v.v_vlin;
			if (v.v_clin)
				vcp->vc_font.height = v.v_clin;
			vcp->vc_resize_user = 1;
			vc_resize(vcp, v.v_cols, v.v_rows);
		}
		console_unlock();
	}

	return 0;
}

/*
 * We handle the console-specific ioctl's here.  We allow the
 * capability to modify any console, not just the fg_console.
 */
int vt_ioctl(struct tty_struct *tty,
	     unsigned int cmd, unsigned long arg)
{
	struct vc_data *vc = tty->driver_data;
	void __user *up = (void __user *)arg;
	int i, perm;
	int ret;

	/*
	 * To have permissions to do most of the vt ioctls, we either have
	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
	 */
	perm = 0;
	if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
		perm = 1;

	ret = vt_k_ioctl(tty, cmd, arg, perm);
	if (ret != -ENOIOCTLCMD)
		return ret;

	ret = vt_io_ioctl(vc, cmd, up, perm);
	if (ret != -ENOIOCTLCMD)
		return ret;

	switch (cmd) {
	case TIOCLINUX:
		return tioclinux(tty, arg);
	case VT_SETMODE:
	{
		struct vt_mode tmp;

		if (!perm)
			return -EPERM;
		if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
			return -EFAULT;
		if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
			return -EINVAL;

		console_lock();
		vc->vt_mode = tmp;
		/* the frsig is ignored, so we set it to 0 */
		vc->vt_mode.frsig = 0;
		put_pid(vc->vt_pid);
		vc->vt_pid = get_pid(task_pid(current));
		/* no switch is required -- saw@shade.msu.ru */
		vc->vt_newvt = -1;
		console_unlock();
		break;
	}

	case VT_GETMODE:
	{
		struct vt_mode tmp;
		int rc;

		console_lock();
		memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
		console_unlock();

		rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
		if (rc)
			return -EFAULT;
		break;
	}

	/*
	 * Returns global vt state. Note that VT 0 is always open, since
	 * it's an alias for the current VT, and people can't use it here.
	 * We cannot return state for more than 16 VTs, since v_state is short.
	 */
	case VT_GETSTATE:
	{
		struct vt_stat __user *vtstat = up;
		unsigned short state, mask;

		if (put_user(fg_console + 1, &vtstat->v_active))
			return -EFAULT;

		state = 1;	/* /dev/tty0 is always open */
		console_lock(); /* required by vt_in_use() */
		for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
				++i, mask <<= 1)
			if (vt_in_use(i))
				state |= mask;
		console_unlock();
		return put_user(state, &vtstat->v_state);
	}

	/*
	 * Returns the first available (non-opened) console.
	 */
	case VT_OPENQRY:
		console_lock(); /* required by vt_in_use() */
		for (i = 0; i < MAX_NR_CONSOLES; ++i)
			if (!vt_in_use(i))
				break;
		console_unlock();
		i = i < MAX_NR_CONSOLES ? (i+1) : -1;
		return put_user(i, (int __user *)arg);

	/*
	 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
	 * with num >= 1 (switches to vt 0, our console, are not allowed, just
	 * to preserve sanity).
	 */
	case VT_ACTIVATE:
		if (!perm)
			return -EPERM;
		if (arg == 0 || arg > MAX_NR_CONSOLES)
			return -ENXIO;

		arg--;
		console_lock();
		ret = vc_allocate(arg);
		console_unlock();
		if (ret)
			return ret;
		set_console(arg);
		break;

	case VT_SETACTIVATE:
		if (!perm)
			return -EPERM;

		return vt_setactivate(up);

	/*
	 * wait until the specified VT has been activated
	 */
	case VT_WAITACTIVE:
		if (!perm)
			return -EPERM;
		if (arg == 0 || arg > MAX_NR_CONSOLES)
			return -ENXIO;
		return vt_waitactive(arg);

	/*
	 * If a vt is under process control, the kernel will not switch to it
	 * immediately, but postpone the operation until the process calls this
	 * ioctl, allowing the switch to complete.
	 *
	 * According to the X sources this is the behavior:
	 *	0:	pending switch-from not OK
	 *	1:	pending switch-from OK
	 *	2:	completed switch-to OK
	 */
	case VT_RELDISP:
		if (!perm)
			return -EPERM;

		console_lock();
		ret = vt_reldisp(vc, arg);
		console_unlock();

		return ret;


	 /*
	  * Disallocate memory associated to VT (but leave VT1)
	  */
	 case VT_DISALLOCATE:
		if (arg > MAX_NR_CONSOLES)
			return -ENXIO;

		if (arg == 0)
			vt_disallocate_all();
		else
			return vt_disallocate(--arg);
		break;

	case VT_RESIZE:
	{
		struct vt_sizes __user *vtsizes = up;
		struct vc_data *vc;
		ushort ll,cc;

		if (!perm)
			return -EPERM;
		if (get_user(ll, &vtsizes->v_rows) ||
		    get_user(cc, &vtsizes->v_cols))
			return -EFAULT;

		console_lock();
		for (i = 0; i < MAX_NR_CONSOLES; i++) {
			vc = vc_cons[i].d;

			if (vc) {
				vc->vc_resize_user = 1;
				/* FIXME: review v tty lock */
				vc_resize(vc_cons[i].d, cc, ll);
			}
		}
		console_unlock();
		break;
	}

	case VT_RESIZEX:
		if (!perm)
			return -EPERM;

		return vt_resizex(vc, up);

	case VT_LOCKSWITCH:
		if (!capable(CAP_SYS_TTY_CONFIG))
			return -EPERM;
		vt_dont_switch = true;
		break;
	case VT_UNLOCKSWITCH:
		if (!capable(CAP_SYS_TTY_CONFIG))
			return -EPERM;
		vt_dont_switch = false;
		break;
	case VT_GETHIFONTMASK:
		return put_user(vc->vc_hi_font_mask,
					(unsigned short __user *)arg);
	case VT_WAITEVENT:
		return vt_event_wait_ioctl((struct vt_event __user *)arg);
	default:
		return -ENOIOCTLCMD;
	}

	return 0;
}

void reset_vc(struct vc_data *vc)
{
	vc->vc_mode = KD_TEXT;
	vt_reset_unicode(vc->vc_num);
	vc->vt_mode.mode = VT_AUTO;
	vc->vt_mode.waitv = 0;
	vc->vt_mode.relsig = 0;
	vc->vt_mode.acqsig = 0;
	vc->vt_mode.frsig = 0;
	put_pid(vc->vt_pid);
	vc->vt_pid = NULL;
	vc->vt_newvt = -1;
	if (!in_interrupt())    /* Via keyboard.c:SAK() - akpm */
		reset_palette(vc);
}

void vc_SAK(struct work_struct *work)
{
	struct vc *vc_con =
		container_of(work, struct vc, SAK_work);
	struct vc_data *vc;
	struct tty_struct *tty;

	console_lock();
	vc = vc_con->d;
	if (vc) {
		/* FIXME: review tty ref counting */
		tty = vc->port.tty;
		/*
		 * SAK should also work in all raw modes and reset
		 * them properly.
		 */
		if (tty)
			__do_SAK(tty);
		reset_vc(vc);
	}
	console_unlock();
}

#ifdef CONFIG_COMPAT

struct compat_consolefontdesc {
	unsigned short charcount;       /* characters in font (256 or 512) */
	unsigned short charheight;      /* scan lines per character (1-32) */
	compat_caddr_t chardata;	/* font data in expanded form */
};

static inline int
compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
			 int perm, struct console_font_op *op)
{
	struct compat_consolefontdesc cfdarg;
	int i;

	if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
		return -EFAULT;

	switch (cmd) {
	case PIO_FONTX:
		if (!perm)
			return -EPERM;
		op->op = KD_FONT_OP_SET;
		op->flags = KD_FONT_FLAG_OLD;
		op->width = 8;
		op->height = cfdarg.charheight;
		op->charcount = cfdarg.charcount;
		op->data = compat_ptr(cfdarg.chardata);
		return con_font_op(vc_cons[fg_console].d, op);
	case GIO_FONTX:
		op->op = KD_FONT_OP_GET;
		op->flags = KD_FONT_FLAG_OLD;
		op->width = 8;
		op->height = cfdarg.charheight;
		op->charcount = cfdarg.charcount;
		op->data = compat_ptr(cfdarg.chardata);
		i = con_font_op(vc_cons[fg_console].d, op);
		if (i)
			return i;
		cfdarg.charheight = op->height;
		cfdarg.charcount = op->charcount;
		if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
			return -EFAULT;
		return 0;
	}
	return -EINVAL;
}

struct compat_console_font_op {
	compat_uint_t op;        /* operation code KD_FONT_OP_* */
	compat_uint_t flags;     /* KD_FONT_FLAG_* */
	compat_uint_t width, height;     /* font size */
	compat_uint_t charcount;
	compat_caddr_t data;    /* font data with height fixed to 32 */
};

static inline int
compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
			 int perm, struct console_font_op *op, struct vc_data *vc)
{
	int i;

	if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
		return -EFAULT;
	if (!perm && op->op != KD_FONT_OP_GET)
		return -EPERM;
	op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
	i = con_font_op(vc, op);
	if (i)
		return i;
	((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
	if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
		return -EFAULT;
	return 0;
}

struct compat_unimapdesc {
	unsigned short entry_ct;
	compat_caddr_t entries;
};

static inline int
compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
			 int perm, struct vc_data *vc)
{
	struct compat_unimapdesc tmp;
	struct unipair __user *tmp_entries;

	if (copy_from_user(&tmp, user_ud, sizeof tmp))
		return -EFAULT;
	tmp_entries = compat_ptr(tmp.entries);
	switch (cmd) {
	case PIO_UNIMAP:
		if (!perm)
			return -EPERM;
		return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
	case GIO_UNIMAP:
		if (!perm && fg_console != vc->vc_num)
			return -EPERM;
		return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
	}
	return 0;
}

long vt_compat_ioctl(struct tty_struct *tty,
	     unsigned int cmd, unsigned long arg)
{
	struct vc_data *vc = tty->driver_data;
	struct console_font_op op;	/* used in multiple places here */
	void __user *up = compat_ptr(arg);
	int perm;

	/*
	 * To have permissions to do most of the vt ioctls, we either have
	 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
	 */
	perm = 0;
	if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
		perm = 1;

	switch (cmd) {
	/*
	 * these need special handlers for incompatible data structures
	 */
	case PIO_FONTX:
	case GIO_FONTX:
		return compat_fontx_ioctl(cmd, up, perm, &op);

	case KDFONTOP:
		return compat_kdfontop_ioctl(up, perm, &op, vc);

	case PIO_UNIMAP:
	case GIO_UNIMAP:
		return compat_unimap_ioctl(cmd, up, perm, vc);

	/*
	 * all these treat 'arg' as an integer
	 */
	case KIOCSOUND:
	case KDMKTONE:
#ifdef CONFIG_X86
	case KDADDIO:
	case KDDELIO:
#endif
	case KDSETMODE:
	case KDMAPDISP:
	case KDUNMAPDISP:
	case KDSKBMODE:
	case KDSKBMETA:
	case KDSKBLED:
	case KDSETLED:
	case KDSIGACCEPT:
	case VT_ACTIVATE:
	case VT_WAITACTIVE:
	case VT_RELDISP:
	case VT_DISALLOCATE:
	case VT_RESIZE:
	case VT_RESIZEX:
		return vt_ioctl(tty, cmd, arg);

	/*
	 * the rest has a compatible data structure behind arg,
	 * but we have to convert it to a proper 64 bit pointer.
	 */
	default:
		return vt_ioctl(tty, cmd, (unsigned long)up);
	}
}


#endif /* CONFIG_COMPAT */


/*
 * Performs the back end of a vt switch. Called under the console
 * semaphore.
 */
static void complete_change_console(struct vc_data *vc)
{
	unsigned char old_vc_mode;
	int old = fg_console;

	last_console = fg_console;

	/*
	 * If we're switching, we could be going from KD_GRAPHICS to
	 * KD_TEXT mode or vice versa, which means we need to blank or
	 * unblank the screen later.
	 */
	old_vc_mode = vc_cons[fg_console].d->vc_mode;
	switch_screen(vc);

	/*
	 * This can't appear below a successful kill_pid().  If it did,
	 * then the *blank_screen operation could occur while X, having
	 * received acqsig, is waking up on another processor.  This
	 * condition can lead to overlapping accesses to the VGA range
	 * and the framebuffer (causing system lockups).
	 *
	 * To account for this we duplicate this code below only if the
	 * controlling process is gone and we've called reset_vc.
	 */
	if (old_vc_mode != vc->vc_mode) {
		if (vc->vc_mode == KD_TEXT)
			do_unblank_screen(1);
		else
			do_blank_screen(1);
	}

	/*
	 * If this new console is under process control, send it a signal
	 * telling it that it has acquired. Also check if it has died and
	 * clean up (similar to logic employed in change_console())
	 */
	if (vc->vt_mode.mode == VT_PROCESS) {
		/*
		 * Send the signal as privileged - kill_pid() will
		 * tell us if the process has gone or something else
		 * is awry
		 */
		if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
		/*
		 * The controlling process has died, so we revert back to
		 * normal operation. In this case, we'll also change back
		 * to KD_TEXT mode. I'm not sure if this is strictly correct
		 * but it saves the agony when the X server dies and the screen
		 * remains blanked due to KD_GRAPHICS! It would be nice to do
		 * this outside of VT_PROCESS but there is no single process
		 * to account for and tracking tty count may be undesirable.
		 */
			reset_vc(vc);

			if (old_vc_mode != vc->vc_mode) {
				if (vc->vc_mode == KD_TEXT)
					do_unblank_screen(1);
				else
					do_blank_screen(1);
			}
		}
	}

	/*
	 * Wake anyone waiting for their VT to activate
	 */
	vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
	return;
}

/*
 * Performs the front-end of a vt switch
 */
void change_console(struct vc_data *new_vc)
{
	struct vc_data *vc;

	if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
		return;

	/*
	 * If this vt is in process mode, then we need to handshake with
	 * that process before switching. Essentially, we store where that
	 * vt wants to switch to and wait for it to tell us when it's done
	 * (via VT_RELDISP ioctl).
	 *
	 * We also check to see if the controlling process still exists.
	 * If it doesn't, we reset this vt to auto mode and continue.
	 * This is a cheap way to track process control. The worst thing
	 * that can happen is: we send a signal to a process, it dies, and
	 * the switch gets "lost" waiting for a response; hopefully, the
	 * user will try again, we'll detect the process is gone (unless
	 * the user waits just the right amount of time :-) and revert the
	 * vt to auto control.
	 */
	vc = vc_cons[fg_console].d;
	if (vc->vt_mode.mode == VT_PROCESS) {
		/*
		 * Send the signal as privileged - kill_pid() will
		 * tell us if the process has gone or something else
		 * is awry.
		 *
		 * We need to set vt_newvt *before* sending the signal or we
		 * have a race.
		 */
		vc->vt_newvt = new_vc->vc_num;
		if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
			/*
			 * It worked. Mark the vt to switch to and
			 * return. The process needs to send us a
			 * VT_RELDISP ioctl to complete the switch.
			 */
			return;
		}

		/*
		 * The controlling process has died, so we revert back to
		 * normal operation. In this case, we'll also change back
		 * to KD_TEXT mode. I'm not sure if this is strictly correct
		 * but it saves the agony when the X server dies and the screen
		 * remains blanked due to KD_GRAPHICS! It would be nice to do
		 * this outside of VT_PROCESS but there is no single process
		 * to account for and tracking tty count may be undesirable.
		 */
		reset_vc(vc);

		/*
		 * Fall through to normal (VT_AUTO) handling of the switch...
		 */
	}

	/*
	 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
	 */
	if (vc->vc_mode == KD_GRAPHICS)
		return;

	complete_change_console(new_vc);
}

/* Perform a kernel triggered VT switch for suspend/resume */

static int disable_vt_switch;

int vt_move_to_console(unsigned int vt, int alloc)
{
	int prev;

	console_lock();
	/* Graphics mode - up to X */
	if (disable_vt_switch) {
		console_unlock();
		return 0;
	}
	prev = fg_console;

	if (alloc && vc_allocate(vt)) {
		/* we can't have a free VC for now. Too bad,
		 * we don't want to mess the screen for now. */
		console_unlock();
		return -ENOSPC;
	}

	if (set_console(vt)) {
		/*
		 * We're unable to switch to the SUSPEND_CONSOLE.
		 * Let the calling function know so it can decide
		 * what to do.
		 */
		console_unlock();
		return -EIO;
	}
	console_unlock();
	if (vt_waitactive(vt + 1)) {
		pr_debug("Suspend: Can't switch VCs.");
		return -EINTR;
	}
	return prev;
}

/*
 * Normally during a suspend, we allocate a new console and switch to it.
 * When we resume, we switch back to the original console.  This switch
 * can be slow, so on systems where the framebuffer can handle restoration
 * of video registers anyways, there's little point in doing the console
 * switch.  This function allows you to disable it by passing it '0'.
 */
void pm_set_vt_switch(int do_switch)
{
	console_lock();
	disable_vt_switch = !do_switch;
	console_unlock();
}
EXPORT_SYMBOL(pm_set_vt_switch);