aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/kernel/ptrace.c
blob: 252ed61a128b8689a3cbacf592031adeeab5c6cc (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
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
/*
 *  Ptrace user space interface.
 *
 *    Copyright IBM Corp. 1999, 2010
 *    Author(s): Denis Joseph Barrow
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/signal.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <linux/seccomp.h>
#include <linux/compat.h>
#include <trace/syscall.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/switch_to.h>
#include "entry.h"

#ifdef CONFIG_COMPAT
#include "compat_ptrace.h"
#endif

#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

void update_cr_regs(struct task_struct *task)
{
	struct pt_regs *regs = task_pt_regs(task);
	struct thread_struct *thread = &task->thread;
	struct per_regs old, new;
	unsigned long cr0_old, cr0_new;
	unsigned long cr2_old, cr2_new;
	int cr0_changed, cr2_changed;

	__ctl_store(cr0_old, 0, 0);
	__ctl_store(cr2_old, 2, 2);
	cr0_new = cr0_old;
	cr2_new = cr2_old;
	/* Take care of the enable/disable of transactional execution. */
	if (MACHINE_HAS_TE) {
		/* Set or clear transaction execution TXC bit 8. */
		cr0_new |= (1UL << 55);
		if (task->thread.per_flags & PER_FLAG_NO_TE)
			cr0_new &= ~(1UL << 55);
		/* Set or clear transaction execution TDC bits 62 and 63. */
		cr2_new &= ~3UL;
		if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
			if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND)
				cr2_new |= 1UL;
			else
				cr2_new |= 2UL;
		}
	}
	/* Take care of enable/disable of guarded storage. */
	if (MACHINE_HAS_GS) {
		cr2_new &= ~(1UL << 4);
		if (task->thread.gs_cb)
			cr2_new |= (1UL << 4);
	}
	/* Load control register 0/2 iff changed */
	cr0_changed = cr0_new != cr0_old;
	cr2_changed = cr2_new != cr2_old;
	if (cr0_changed)
		__ctl_load(cr0_new, 0, 0);
	if (cr2_changed)
		__ctl_load(cr2_new, 2, 2);
	/* Copy user specified PER registers */
	new.control = thread->per_user.control;
	new.start = thread->per_user.start;
	new.end = thread->per_user.end;

	/* merge TIF_SINGLE_STEP into user specified PER registers. */
	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
	    test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
		if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
			new.control |= PER_EVENT_BRANCH;
		else
			new.control |= PER_EVENT_IFETCH;
		new.control |= PER_CONTROL_SUSPENSION;
		new.control |= PER_EVENT_TRANSACTION_END;
		if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
			new.control |= PER_EVENT_IFETCH;
		new.start = 0;
		new.end = -1UL;
	}

	/* Take care of the PER enablement bit in the PSW. */
	if (!(new.control & PER_EVENT_MASK)) {
		regs->psw.mask &= ~PSW_MASK_PER;
		return;
	}
	regs->psw.mask |= PSW_MASK_PER;
	__ctl_store(old, 9, 11);
	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
		__ctl_load(new, 9, 11);
}

void user_enable_single_step(struct task_struct *task)
{
	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
}

void user_disable_single_step(struct task_struct *task)
{
	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
}

void user_enable_block_step(struct task_struct *task)
{
	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
	set_tsk_thread_flag(task, TIF_BLOCK_STEP);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Clear all debugging related fields.
 */
void ptrace_disable(struct task_struct *task)
{
	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
	clear_pt_regs_flag(task_pt_regs(task), PIF_PER_TRAP);
	task->thread.per_flags = 0;
}

#define __ADDR_MASK 7

static inline unsigned long __peek_user_per(struct task_struct *child,
					    addr_t addr)
{
	struct per_struct_kernel *dummy = NULL;

	if (addr == (addr_t) &dummy->cr9)
		/* Control bits of the active per set. */
		return test_thread_flag(TIF_SINGLE_STEP) ?
			PER_EVENT_IFETCH : child->thread.per_user.control;
	else if (addr == (addr_t) &dummy->cr10)
		/* Start address of the active per set. */
		return test_thread_flag(TIF_SINGLE_STEP) ?
			0 : child->thread.per_user.start;
	else if (addr == (addr_t) &dummy->cr11)
		/* End address of the active per set. */
		return test_thread_flag(TIF_SINGLE_STEP) ?
			-1UL : child->thread.per_user.end;
	else if (addr == (addr_t) &dummy->bits)
		/* Single-step bit. */
		return test_thread_flag(TIF_SINGLE_STEP) ?
			(1UL << (BITS_PER_LONG - 1)) : 0;
	else if (addr == (addr_t) &dummy->starting_addr)
		/* Start address of the user specified per set. */
		return child->thread.per_user.start;
	else if (addr == (addr_t) &dummy->ending_addr)
		/* End address of the user specified per set. */
		return child->thread.per_user.end;
	else if (addr == (addr_t) &dummy->perc_atmid)
		/* PER code, ATMID and AI of the last PER trap */
		return (unsigned long)
			child->thread.per_event.cause << (BITS_PER_LONG - 16);
	else if (addr == (addr_t) &dummy->address)
		/* Address of the last PER trap */
		return child->thread.per_event.address;
	else if (addr == (addr_t) &dummy->access_id)
		/* Access id of the last PER trap */
		return (unsigned long)
			child->thread.per_event.paid << (BITS_PER_LONG - 8);
	return 0;
}

/*
 * Read the word at offset addr from the user area of a process. The
 * trouble here is that the information is littered over different
 * locations. The process registers are found on the kernel stack,
 * the floating point stuff and the trace settings are stored in
 * the task structure. In addition the different structures in
 * struct user contain pad bytes that should be read as zeroes.
 * Lovely...
 */
static unsigned long __peek_user(struct task_struct *child, addr_t addr)
{
	struct user *dummy = NULL;
	addr_t offset, tmp;

	if (addr < (addr_t) &dummy->regs.acrs) {
		/*
		 * psw and gprs are stored on the stack
		 */
		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
		if (addr == (addr_t) &dummy->regs.psw.mask) {
			/* Return a clean psw mask. */
			tmp &= PSW_MASK_USER | PSW_MASK_RI;
			tmp |= PSW_USER_BITS;
		}

	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.acrs;
		/*
		 * Very special case: old & broken 64 bit gdb reading
		 * from acrs[15]. Result is a 64 bit value. Read the
		 * 32 bit acrs[15] value and shift it by 32. Sick...
		 */
		if (addr == (addr_t) &dummy->regs.acrs[15])
			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
		else
			tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);

	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;

	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
		/*
		 * prevent reads of padding hole between
		 * orig_gpr2 and fp_regs on s390.
		 */
		tmp = 0;

	} else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) {
		/*
		 * floating point control reg. is in the thread structure
		 */
		tmp = child->thread.fpu.fpc;
		tmp <<= BITS_PER_LONG - 32;

	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are either in child->thread.fpu
		 * or the child->thread.fpu.vxrs array
		 */
		offset = addr - (addr_t) &dummy->regs.fp_regs.fprs;
		if (MACHINE_HAS_VX)
			tmp = *(addr_t *)
			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
		else
			tmp = *(addr_t *)
			       ((addr_t) child->thread.fpu.fprs + offset);

	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
		/*
		 * Handle access to the per_info structure.
		 */
		addr -= (addr_t) &dummy->regs.per_info;
		tmp = __peek_user_per(child, addr);

	} else
		tmp = 0;

	return tmp;
}

static int
peek_user(struct task_struct *child, addr_t addr, addr_t data)
{
	addr_t tmp, mask;

	/*
	 * Stupid gdb peeks/pokes the access registers in 64 bit with
	 * an alignment of 4. Programmers from hell...
	 */
	mask = __ADDR_MASK;
	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
		mask = 3;
	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
		return -EIO;

	tmp = __peek_user(child, addr);
	return put_user(tmp, (addr_t __user *) data);
}

static inline void __poke_user_per(struct task_struct *child,
				   addr_t addr, addr_t data)
{
	struct per_struct_kernel *dummy = NULL;

	/*
	 * There are only three fields in the per_info struct that the
	 * debugger user can write to.
	 * 1) cr9: the debugger wants to set a new PER event mask
	 * 2) starting_addr: the debugger wants to set a new starting
	 *    address to use with the PER event mask.
	 * 3) ending_addr: the debugger wants to set a new ending
	 *    address to use with the PER event mask.
	 * The user specified PER event mask and the start and end
	 * addresses are used only if single stepping is not in effect.
	 * Writes to any other field in per_info are ignored.
	 */
	if (addr == (addr_t) &dummy->cr9)
		/* PER event mask of the user specified per set. */
		child->thread.per_user.control =
			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
	else if (addr == (addr_t) &dummy->starting_addr)
		/* Starting address of the user specified per set. */
		child->thread.per_user.start = data;
	else if (addr == (addr_t) &dummy->ending_addr)
		/* Ending address of the user specified per set. */
		child->thread.per_user.end = data;
}

/*
 * Write a word to the user area of a process at location addr. This
 * operation does have an additional problem compared to peek_user.
 * Stores to the program status word and on the floating point
 * control register needs to get checked for validity.
 */
static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user *dummy = NULL;
	addr_t offset;

	if (addr < (addr_t) &dummy->regs.acrs) {
		/*
		 * psw and gprs are stored on the stack
		 */
		if (addr == (addr_t) &dummy->regs.psw.mask) {
			unsigned long mask = PSW_MASK_USER;

			mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
			if ((data ^ PSW_USER_BITS) & ~mask)
				/* Invalid psw mask. */
				return -EINVAL;
			if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
				/* Invalid address-space-control bits */
				return -EINVAL;
			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
				/* Invalid addressing mode bits */
				return -EINVAL;
		}
		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;

	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.acrs;
		/*
		 * Very special case: old & broken 64 bit gdb writing
		 * to acrs[15] with a 64 bit value. Ignore the lower
		 * half of the value and write the upper 32 bit to
		 * acrs[15]. Sick...
		 */
		if (addr == (addr_t) &dummy->regs.acrs[15])
			child->thread.acrs[15] = (unsigned int) (data >> 32);
		else
			*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;

	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		task_pt_regs(child)->orig_gpr2 = data;

	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
		/*
		 * prevent writes of padding hole between
		 * orig_gpr2 and fp_regs on s390.
		 */
		return 0;

	} else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) {
		/*
		 * floating point control reg. is in the thread structure
		 */
		if ((unsigned int) data != 0 ||
		    test_fp_ctl(data >> (BITS_PER_LONG - 32)))
			return -EINVAL;
		child->thread.fpu.fpc = data >> (BITS_PER_LONG - 32);

	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are either in child->thread.fpu
		 * or the child->thread.fpu.vxrs array
		 */
		offset = addr - (addr_t) &dummy->regs.fp_regs.fprs;
		if (MACHINE_HAS_VX)
			*(addr_t *)((addr_t)
				child->thread.fpu.vxrs + 2*offset) = data;
		else
			*(addr_t *)((addr_t)
				child->thread.fpu.fprs + offset) = data;

	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
		/*
		 * Handle access to the per_info structure.
		 */
		addr -= (addr_t) &dummy->regs.per_info;
		__poke_user_per(child, addr, data);

	}

	return 0;
}

static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
	addr_t mask;

	/*
	 * Stupid gdb peeks/pokes the access registers in 64 bit with
	 * an alignment of 4. Programmers from hell indeed...
	 */
	mask = __ADDR_MASK;
	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
		mask = 3;
	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
		return -EIO;

	return __poke_user(child, addr, data);
}

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	ptrace_area parea; 
	int copied, ret;

	switch (request) {
	case PTRACE_PEEKUSR:
		/* read the word at location addr in the USER area. */
		return peek_user(child, addr, data);

	case PTRACE_POKEUSR:
		/* write the word at location addr in the USER area */
		return poke_user(child, addr, data);

	case PTRACE_PEEKUSR_AREA:
	case PTRACE_POKEUSR_AREA:
		if (copy_from_user(&parea, (void __force __user *) addr,
							sizeof(parea)))
			return -EFAULT;
		addr = parea.kernel_addr;
		data = parea.process_addr;
		copied = 0;
		while (copied < parea.len) {
			if (request == PTRACE_PEEKUSR_AREA)
				ret = peek_user(child, addr, data);
			else {
				addr_t utmp;
				if (get_user(utmp,
					     (addr_t __force __user *) data))
					return -EFAULT;
				ret = poke_user(child, addr, utmp);
			}
			if (ret)
				return ret;
			addr += sizeof(unsigned long);
			data += sizeof(unsigned long);
			copied += sizeof(unsigned long);
		}
		return 0;
	case PTRACE_GET_LAST_BREAK:
		put_user(child->thread.last_break,
			 (unsigned long __user *) data);
		return 0;
	case PTRACE_ENABLE_TE:
		if (!MACHINE_HAS_TE)
			return -EIO;
		child->thread.per_flags &= ~PER_FLAG_NO_TE;
		return 0;
	case PTRACE_DISABLE_TE:
		if (!MACHINE_HAS_TE)
			return -EIO;
		child->thread.per_flags |= PER_FLAG_NO_TE;
		child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
		return 0;
	case PTRACE_TE_ABORT_RAND:
		if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE))
			return -EIO;
		switch (data) {
		case 0UL:
			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
			break;
		case 1UL:
			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
			break;
		case 2UL:
			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
			break;
		default:
			return -EINVAL;
		}
		return 0;
	default:
		return ptrace_request(child, request, addr, data);
	}
}

#ifdef CONFIG_COMPAT
/*
 * Now the fun part starts... a 31 bit program running in the
 * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 * to handle, the difference to the 64 bit versions of the requests
 * is that the access is done in multiples of 4 byte instead of
 * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 * is a 31 bit program too, the content of struct user can be
 * emulated. A 31 bit program peeking into the struct user of
 * a 64 bit program is a no-no.
 */

/*
 * Same as peek_user_per but for a 31 bit program.
 */
static inline __u32 __peek_user_per_compat(struct task_struct *child,
					   addr_t addr)
{
	struct compat_per_struct_kernel *dummy32 = NULL;

	if (addr == (addr_t) &dummy32->cr9)
		/* Control bits of the active per set. */
		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
			PER_EVENT_IFETCH : child->thread.per_user.control;
	else if (addr == (addr_t) &dummy32->cr10)
		/* Start address of the active per set. */
		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
			0 : child->thread.per_user.start;
	else if (addr == (addr_t) &dummy32->cr11)
		/* End address of the active per set. */
		return test_thread_flag(TIF_SINGLE_STEP) ?
			PSW32_ADDR_INSN : child->thread.per_user.end;
	else if (addr == (addr_t) &dummy32->bits)
		/* Single-step bit. */
		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
			0x80000000 : 0;
	else if (addr == (addr_t) &dummy32->starting_addr)
		/* Start address of the user specified per set. */
		return (__u32) child->thread.per_user.start;
	else if (addr == (addr_t) &dummy32->ending_addr)
		/* End address of the user specified per set. */
		return (__u32) child->thread.per_user.end;
	else if (addr == (addr_t) &dummy32->perc_atmid)
		/* PER code, ATMID and AI of the last PER trap */
		return (__u32) child->thread.per_event.cause << 16;
	else if (addr == (addr_t) &dummy32->address)
		/* Address of the last PER trap */
		return (__u32) child->thread.per_event.address;
	else if (addr == (addr_t) &dummy32->access_id)
		/* Access id of the last PER trap */
		return (__u32) child->thread.per_event.paid << 24;
	return 0;
}

/*
 * Same as peek_user but for a 31 bit program.
 */
static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
{
	struct compat_user *dummy32 = NULL;
	addr_t offset;
	__u32 tmp;

	if (addr < (addr_t) &dummy32->regs.acrs) {
		struct pt_regs *regs = task_pt_regs(child);
		/*
		 * psw and gprs are stored on the stack
		 */
		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			/* Fake a 31 bit psw mask. */
			tmp = (__u32)(regs->psw.mask >> 32);
			tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
			tmp |= PSW32_USER_BITS;
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Fake a 31 bit psw address. */
			tmp = (__u32) regs->psw.addr |
				(__u32)(regs->psw.mask & PSW_MASK_BA);
		} else {
			/* gpr 0-15 */
			tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);

	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
		/*
		 * prevent reads of padding hole between
		 * orig_gpr2 and fp_regs on s390.
		 */
		tmp = 0;

	} else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) {
		/*
		 * floating point control reg. is in the thread structure
		 */
		tmp = child->thread.fpu.fpc;

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are either in child->thread.fpu
		 * or the child->thread.fpu.vxrs array
		 */
		offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs;
		if (MACHINE_HAS_VX)
			tmp = *(__u32 *)
			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
		else
			tmp = *(__u32 *)
			       ((addr_t) child->thread.fpu.fprs + offset);

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * Handle access to the per_info structure.
		 */
		addr -= (addr_t) &dummy32->regs.per_info;
		tmp = __peek_user_per_compat(child, addr);

	} else
		tmp = 0;

	return tmp;
}

static int peek_user_compat(struct task_struct *child,
			    addr_t addr, addr_t data)
{
	__u32 tmp;

	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
		return -EIO;

	tmp = __peek_user_compat(child, addr);
	return put_user(tmp, (__u32 __user *) data);
}

/*
 * Same as poke_user_per but for a 31 bit program.
 */
static inline void __poke_user_per_compat(struct task_struct *child,
					  addr_t addr, __u32 data)
{
	struct compat_per_struct_kernel *dummy32 = NULL;

	if (addr == (addr_t) &dummy32->cr9)
		/* PER event mask of the user specified per set. */
		child->thread.per_user.control =
			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
	else if (addr == (addr_t) &dummy32->starting_addr)
		/* Starting address of the user specified per set. */
		child->thread.per_user.start = data;
	else if (addr == (addr_t) &dummy32->ending_addr)
		/* Ending address of the user specified per set. */
		child->thread.per_user.end = data;
}

/*
 * Same as poke_user but for a 31 bit program.
 */
static int __poke_user_compat(struct task_struct *child,
			      addr_t addr, addr_t data)
{
	struct compat_user *dummy32 = NULL;
	__u32 tmp = (__u32) data;
	addr_t offset;

	if (addr < (addr_t) &dummy32->regs.acrs) {
		struct pt_regs *regs = task_pt_regs(child);
		/*
		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
		 */
		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			__u32 mask = PSW32_MASK_USER;

			mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
			/* Build a 64 bit psw mask from 31 bit mask. */
			if ((tmp ^ PSW32_USER_BITS) & ~mask)
				/* Invalid psw mask. */
				return -EINVAL;
			if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
				/* Invalid address-space-control bits */
				return -EINVAL;
			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
				(regs->psw.mask & PSW_MASK_BA) |
				(__u64)(tmp & mask) << 32;
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Build a 64 bit psw address from 31 bit address. */
			regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
			/* Transfer 31 bit amode bit to psw mask. */
			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
				(__u64)(tmp & PSW32_ADDR_AMODE);
		} else {
			/* gpr 0-15 */
			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;

	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
		/*
		 * prevent writess of padding hole between
		 * orig_gpr2 and fp_regs on s390.
		 */
		return 0;

	} else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) {
		/*
		 * floating point control reg. is in the thread structure
		 */
		if (test_fp_ctl(tmp))
			return -EINVAL;
		child->thread.fpu.fpc = data;

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are either in child->thread.fpu
		 * or the child->thread.fpu.vxrs array
		 */
		offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs;
		if (MACHINE_HAS_VX)
			*(__u32 *)((addr_t)
				child->thread.fpu.vxrs + 2*offset) = tmp;
		else
			*(__u32 *)((addr_t)
				child->thread.fpu.fprs + offset) = tmp;

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * Handle access to the per_info structure.
		 */
		addr -= (addr_t) &dummy32->regs.per_info;
		__poke_user_per_compat(child, addr, data);
	}

	return 0;
}

static int poke_user_compat(struct task_struct *child,
			    addr_t addr, addr_t data)
{
	if (!is_compat_task() || (addr & 3) ||
	    addr > sizeof(struct compat_user) - 3)
		return -EIO;

	return __poke_user_compat(child, addr, data);
}

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
			compat_ulong_t caddr, compat_ulong_t cdata)
{
	unsigned long addr = caddr;
	unsigned long data = cdata;
	compat_ptrace_area parea;
	int copied, ret;

	switch (request) {
	case PTRACE_PEEKUSR:
		/* read the word at location addr in the USER area. */
		return peek_user_compat(child, addr, data);

	case PTRACE_POKEUSR:
		/* write the word at location addr in the USER area */
		return poke_user_compat(child, addr, data);

	case PTRACE_PEEKUSR_AREA:
	case PTRACE_POKEUSR_AREA:
		if (copy_from_user(&parea, (void __force __user *) addr,
							sizeof(parea)))
			return -EFAULT;
		addr = parea.kernel_addr;
		data = parea.process_addr;
		copied = 0;
		while (copied < parea.len) {
			if (request == PTRACE_PEEKUSR_AREA)
				ret = peek_user_compat(child, addr, data);
			else {
				__u32 utmp;
				if (get_user(utmp,
					     (__u32 __force __user *) data))
					return -EFAULT;
				ret = poke_user_compat(child, addr, utmp);
			}
			if (ret)
				return ret;
			addr += sizeof(unsigned int);
			data += sizeof(unsigned int);
			copied += sizeof(unsigned int);
		}
		return 0;
	case PTRACE_GET_LAST_BREAK:
		put_user(child->thread.last_break,
			 (unsigned int __user *) data);
		return 0;
	}
	return compat_ptrace_request(child, request, addr, data);
}
#endif

asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
{
	unsigned long mask = -1UL;

	/*
	 * The sysc_tracesys code in entry.S stored the system
	 * call number to gprs[2].
	 */
	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
	    (tracehook_report_syscall_entry(regs) ||
	     regs->gprs[2] >= NR_syscalls)) {
		/*
		 * Tracing decided this syscall should not happen or the
		 * debugger stored an invalid system call number. Skip
		 * the system call and the system call restart handling.
		 */
		clear_pt_regs_flag(regs, PIF_SYSCALL);
		return -1;
	}

	/* Do the secure computing check after ptrace. */
	if (secure_computing(NULL)) {
		/* seccomp failures shouldn't expose any additional code. */
		return -1;
	}

	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
		trace_sys_enter(regs, regs->gprs[2]);

	if (is_compat_task())
		mask = 0xffffffff;

	audit_syscall_entry(regs->gprs[2], regs->orig_gpr2 & mask,
			    regs->gprs[3] &mask, regs->gprs[4] &mask,
			    regs->gprs[5] &mask);

	return regs->gprs[2];
}

asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
{
	audit_syscall_exit(regs);

	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
		trace_sys_exit(regs, regs->gprs[2]);

	if (test_thread_flag(TIF_SYSCALL_TRACE))
		tracehook_report_syscall_exit(regs, 0);
}

/*
 * user_regset definitions.
 */

static int s390_regs_get(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 void *kbuf, void __user *ubuf)
{
	if (target == current)
		save_access_regs(target->thread.acrs);

	if (kbuf) {
		unsigned long *k = kbuf;
		while (count > 0) {
			*k++ = __peek_user(target, pos);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		unsigned long __user *u = ubuf;
		while (count > 0) {
			if (__put_user(__peek_user(target, pos), u++))
				return -EFAULT;
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}
	return 0;
}

static int s390_regs_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	int rc = 0;

	if (target == current)
		save_access_regs(target->thread.acrs);

	if (kbuf) {
		const unsigned long *k = kbuf;
		while (count > 0 && !rc) {
			rc = __poke_user(target, pos, *k++);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		const unsigned long  __user *u = ubuf;
		while (count > 0 && !rc) {
			unsigned long word;
			rc = __get_user(word, u++);
			if (rc)
				break;
			rc = __poke_user(target, pos, word);
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}

	if (rc == 0 && target == current)
		restore_access_regs(target->thread.acrs);

	return rc;
}

static int s390_fpregs_get(struct task_struct *target,
			   const struct user_regset *regset, unsigned int pos,
			   unsigned int count, void *kbuf, void __user *ubuf)
{
	_s390_fp_regs fp_regs;

	if (target == current)
		save_fpu_regs();

	fp_regs.fpc = target->thread.fpu.fpc;
	fpregs_store(&fp_regs, &target->thread.fpu);

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   &fp_regs, 0, -1);
}

static int s390_fpregs_set(struct task_struct *target,
			   const struct user_regset *regset, unsigned int pos,
			   unsigned int count, const void *kbuf,
			   const void __user *ubuf)
{
	int rc = 0;
	freg_t fprs[__NUM_FPRS];

	if (target == current)
		save_fpu_regs();

	if (MACHINE_HAS_VX)
		convert_vx_to_fp(fprs, target->thread.fpu.vxrs);
	else
		memcpy(&fprs, target->thread.fpu.fprs, sizeof(fprs));

	/* If setting FPC, must validate it first. */
	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
		u32 ufpc[2] = { target->thread.fpu.fpc, 0 };
		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
					0, offsetof(s390_fp_regs, fprs));
		if (rc)
			return rc;
		if (ufpc[1] != 0 || test_fp_ctl(ufpc[0]))
			return -EINVAL;
		target->thread.fpu.fpc = ufpc[0];
	}

	if (rc == 0 && count > 0)
		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					fprs, offsetof(s390_fp_regs, fprs), -1);
	if (rc)
		return rc;

	if (MACHINE_HAS_VX)
		convert_fp_to_vx(target->thread.fpu.vxrs, fprs);
	else
		memcpy(target->thread.fpu.fprs, &fprs, sizeof(fprs));

	return rc;
}

static int s390_last_break_get(struct task_struct *target,
			       const struct user_regset *regset,
			       unsigned int pos, unsigned int count,
			       void *kbuf, void __user *ubuf)
{
	if (count > 0) {
		if (kbuf) {
			unsigned long *k = kbuf;
			*k = target->thread.last_break;
		} else {
			unsigned long  __user *u = ubuf;
			if (__put_user(target->thread.last_break, u))
				return -EFAULT;
		}
	}
	return 0;
}

static int s390_last_break_set(struct task_struct *target,
			       const struct user_regset *regset,
			       unsigned int pos, unsigned int count,
			       const void *kbuf, const void __user *ubuf)
{
	return 0;
}

static int s390_tdb_get(struct task_struct *target,
			const struct user_regset *regset,
			unsigned int pos, unsigned int count,
			void *kbuf, void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	unsigned char *data;

	if (!(regs->int_code & 0x200))
		return -ENODATA;
	data = target->thread.trap_tdb;
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, data, 0, 256);
}

static int s390_tdb_set(struct task_struct *target,
			const struct user_regset *regset,
			unsigned int pos, unsigned int count,
			const void *kbuf, const void __user *ubuf)
{
	return 0;
}

static int s390_vxrs_low_get(struct task_struct *target,
			     const struct user_regset *regset,
			     unsigned int pos, unsigned int count,
			     void *kbuf, void __user *ubuf)
{
	__u64 vxrs[__NUM_VXRS_LOW];
	int i;

	if (!MACHINE_HAS_VX)
		return -ENODEV;
	if (target == current)
		save_fpu_regs();
	for (i = 0; i < __NUM_VXRS_LOW; i++)
		vxrs[i] = *((__u64 *)(target->thread.fpu.vxrs + i) + 1);
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
}

static int s390_vxrs_low_set(struct task_struct *target,
			     const struct user_regset *regset,
			     unsigned int pos, unsigned int count,
			     const void *kbuf, const void __user *ubuf)
{
	__u64 vxrs[__NUM_VXRS_LOW];
	int i, rc;

	if (!MACHINE_HAS_VX)
		return -ENODEV;
	if (target == current)
		save_fpu_regs();

	for (i = 0; i < __NUM_VXRS_LOW; i++)
		vxrs[i] = *((__u64 *)(target->thread.fpu.vxrs + i) + 1);

	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
	if (rc == 0)
		for (i = 0; i < __NUM_VXRS_LOW; i++)
			*((__u64 *)(target->thread.fpu.vxrs + i) + 1) = vxrs[i];

	return rc;
}

static int s390_vxrs_high_get(struct task_struct *target,
			      const struct user_regset *regset,
			      unsigned int pos, unsigned int count,
			      void *kbuf, void __user *ubuf)
{
	__vector128 vxrs[__NUM_VXRS_HIGH];

	if (!MACHINE_HAS_VX)
		return -ENODEV;
	if (target == current)
		save_fpu_regs();
	memcpy(vxrs, target->thread.fpu.vxrs + __NUM_VXRS_LOW, sizeof(vxrs));

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
}

static int s390_vxrs_high_set(struct task_struct *target,
			      const struct user_regset *regset,
			      unsigned int pos, unsigned int count,
			      const void *kbuf, const void __user *ubuf)
{
	int rc;

	if (!MACHINE_HAS_VX)
		return -ENODEV;
	if (target == current)
		save_fpu_regs();

	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				target->thread.fpu.vxrs + __NUM_VXRS_LOW, 0, -1);
	return rc;
}

static int s390_system_call_get(struct task_struct *target,
				const struct user_regset *regset,
				unsigned int pos, unsigned int count,
				void *kbuf, void __user *ubuf)
{
	unsigned int *data = &target->thread.system_call;
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   data, 0, sizeof(unsigned int));
}

static int s390_system_call_set(struct task_struct *target,
				const struct user_regset *regset,
				unsigned int pos, unsigned int count,
				const void *kbuf, const void __user *ubuf)
{
	unsigned int *data = &target->thread.system_call;
	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				  data, 0, sizeof(unsigned int));
}

static int s390_gs_cb_get(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  void *kbuf, void __user *ubuf)
{
	struct gs_cb *data = target->thread.gs_cb;

	if (!MACHINE_HAS_GS)
		return -ENODEV;
	if (!data)
		return -ENODATA;
	if (target == current)
		save_gs_cb(data);
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   data, 0, sizeof(struct gs_cb));
}

static int s390_gs_cb_set(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  const void *kbuf, const void __user *ubuf)
{
	struct gs_cb *data = target->thread.gs_cb;
	int rc;

	if (!MACHINE_HAS_GS)
		return -ENODEV;
	if (!data) {
		data = kzalloc(sizeof(*data), GFP_KERNEL);
		if (!data)
			return -ENOMEM;
		data->gsd = 25;
		target->thread.gs_cb = data;
		if (target == current)
			__ctl_set_bit(2, 4);
	} else if (target == current) {
		save_gs_cb(data);
	}
	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				data, 0, sizeof(struct gs_cb));
	if (target == current)
		restore_gs_cb(data);
	return rc;
}

static int s390_gs_bc_get(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  void *kbuf, void __user *ubuf)
{
	struct gs_cb *data = target->thread.gs_bc_cb;

	if (!MACHINE_HAS_GS)
		return -ENODEV;
	if (!data)
		return -ENODATA;
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   data, 0, sizeof(struct gs_cb));
}

static int s390_gs_bc_set(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  const void *kbuf, const void __user *ubuf)
{
	struct gs_cb *data = target->thread.gs_bc_cb;

	if (!MACHINE_HAS_GS)
		return -ENODEV;
	if (!data) {
		data = kzalloc(sizeof(*data), GFP_KERNEL);
		if (!data)
			return -ENOMEM;
		target->thread.gs_bc_cb = data;
	}
	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				  data, 0, sizeof(struct gs_cb));
}

static const struct user_regset s390_regsets[] = {
	{
		.core_note_type = NT_PRSTATUS,
		.n = sizeof(s390_regs) / sizeof(long),
		.size = sizeof(long),
		.align = sizeof(long),
		.get = s390_regs_get,
		.set = s390_regs_set,
	},
	{
		.core_note_type = NT_PRFPREG,
		.n = sizeof(s390_fp_regs) / sizeof(long),
		.size = sizeof(long),
		.align = sizeof(long),
		.get = s390_fpregs_get,
		.set = s390_fpregs_set,
	},
	{
		.core_note_type = NT_S390_SYSTEM_CALL,
		.n = 1,
		.size = sizeof(unsigned int),
		.align = sizeof(unsigned int),
		.get = s390_system_call_get,
		.set = s390_system_call_set,
	},
	{
		.core_note_type = NT_S390_LAST_BREAK,
		.n = 1,
		.size = sizeof(long),
		.align = sizeof(long),
		.get = s390_last_break_get,
		.set = s390_last_break_set,
	},
	{
		.core_note_type = NT_S390_TDB,
		.n = 1,
		.size = 256,
		.align = 1,
		.get = s390_tdb_get,
		.set = s390_tdb_set,
	},
	{
		.core_note_type = NT_S390_VXRS_LOW,
		.n = __NUM_VXRS_LOW,
		.size = sizeof(__u64),
		.align = sizeof(__u64),
		.get = s390_vxrs_low_get,
		.set = s390_vxrs_low_set,
	},
	{
		.core_note_type = NT_S390_VXRS_HIGH,
		.n = __NUM_VXRS_HIGH,
		.size = sizeof(__vector128),
		.align = sizeof(__vector128),
		.get = s390_vxrs_high_get,
		.set = s390_vxrs_high_set,
	},
	{
		.core_note_type = NT_S390_GS_CB,
		.n = sizeof(struct gs_cb) / sizeof(__u64),
		.size = sizeof(__u64),
		.align = sizeof(__u64),
		.get = s390_gs_cb_get,
		.set = s390_gs_cb_set,
	},
	{
		.core_note_type = NT_S390_GS_BC,
		.n = sizeof(struct gs_cb) / sizeof(__u64),
		.size = sizeof(__u64),
		.align = sizeof(__u64),
		.get = s390_gs_bc_get,
		.set = s390_gs_bc_set,
	},
};

static const struct user_regset_view user_s390_view = {
	.name = UTS_MACHINE,
	.e_machine = EM_S390,
	.regsets = s390_regsets,
	.n = ARRAY_SIZE(s390_regsets)
};

#ifdef CONFIG_COMPAT
static int s390_compat_regs_get(struct task_struct *target,
				const struct user_regset *regset,
				unsigned int pos, unsigned int count,
				void *kbuf, void __user *ubuf)
{
	if (target == current)
		save_access_regs(target->thread.acrs);

	if (kbuf) {
		compat_ulong_t *k = kbuf;
		while (count > 0) {
			*k++ = __peek_user_compat(target, pos);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		compat_ulong_t __user *u = ubuf;
		while (count > 0) {
			if (__put_user(__peek_user_compat(target, pos), u++))
				return -EFAULT;
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}
	return 0;
}

static int s390_compat_regs_set(struct task_struct *target,
				const struct user_regset *regset,
				unsigned int pos, unsigned int count,
				const void *kbuf, const void __user *ubuf)
{
	int rc = 0;

	if (target == current)
		save_access_regs(target->thread.acrs);

	if (kbuf) {
		const compat_ulong_t *k = kbuf;
		while (count > 0 && !rc) {
			rc = __poke_user_compat(target, pos, *k++);
			count -= sizeof(*k);
			pos += sizeof(*k);
		}
	} else {
		const compat_ulong_t  __user *u = ubuf;
		while (count > 0 && !rc) {
			compat_ulong_t word;
			rc = __get_user(word, u++);
			if (rc)
				break;
			rc = __poke_user_compat(target, pos, word);
			count -= sizeof(*u);
			pos += sizeof(*u);
		}
	}

	if (rc == 0 && target == current)
		restore_access_regs(target->thread.acrs);

	return rc;
}

static int s390_compat_regs_high_get(struct task_struct *target,
				     const struct user_regset *regset,
				     unsigned int pos, unsigned int count,
				     void *kbuf, void __user *ubuf)
{
	compat_ulong_t *gprs_high;

	gprs_high = (compat_ulong_t *)
		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
	if (kbuf) {
		compat_ulong_t *k = kbuf;
		while (count > 0) {
			*k++ = *gprs_high;
			gprs_high += 2;
			count -= sizeof(*k);
		}
	} else {
		compat_ulong_t __user *u = ubuf;
		while (count > 0) {
			if (__put_user(*gprs_high, u++))
				return -EFAULT;
			gprs_high += 2;
			count -= sizeof(*u);
		}
	}
	return 0;
}

static int s390_compat_regs_high_set(struct task_struct *target,
				     const struct user_regset *regset,
				     unsigned int pos, unsigned int count,
				     const void *kbuf, const void __user *ubuf)
{
	compat_ulong_t *gprs_high;
	int rc = 0;

	gprs_high = (compat_ulong_t *)
		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
	if (kbuf) {
		const compat_ulong_t *k = kbuf;
		while (count > 0) {
			*gprs_high = *k++;
			*gprs_high += 2;
			count -= sizeof(*k);
		}
	} else {
		const compat_ulong_t  __user *u = ubuf;
		while (count > 0 && !rc) {
			unsigned long word;
			rc = __get_user(word, u++);
			if (rc)
				break;
			*gprs_high = word;
			*gprs_high += 2;
			count -= sizeof(*u);
		}
	}

	return rc;
}

static int s390_compat_last_break_get(struct task_struct *target,
				      const struct user_regset *regset,
				      unsigned int pos, unsigned int count,
				      void *kbuf, void __user *ubuf)
{
	compat_ulong_t last_break;

	if (count > 0) {
		last_break = target->thread.last_break;
		if (kbuf) {
			unsigned long *k = kbuf;
			*k = last_break;
		} else {
			unsigned long  __user *u = ubuf;
			if (__put_user(last_break, u))
				return -EFAULT;
		}
	}
	return 0;
}

static int s390_compat_last_break_set(struct task_struct *target,
				      const struct user_regset *regset,
				      unsigned int pos, unsigned int count,
				      const void *kbuf, const void __user *ubuf)
{
	return 0;
}

static const struct user_regset s390_compat_regsets[] = {
	{
		.core_note_type = NT_PRSTATUS,
		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
		.size = sizeof(compat_long_t),
		.align = sizeof(compat_long_t),
		.get = s390_compat_regs_get,
		.set = s390_compat_regs_set,
	},
	{
		.core_note_type = NT_PRFPREG,
		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
		.size = sizeof(compat_long_t),
		.align = sizeof(compat_long_t),
		.get = s390_fpregs_get,
		.set = s390_fpregs_set,
	},
	{
		.core_note_type = NT_S390_SYSTEM_CALL,
		.n = 1,
		.size = sizeof(compat_uint_t),
		.align = sizeof(compat_uint_t),
		.get = s390_system_call_get,
		.set = s390_system_call_set,
	},
	{
		.core_note_type = NT_S390_LAST_BREAK,
		.n = 1,
		.size = sizeof(long),
		.align = sizeof(long),
		.get = s390_compat_last_break_get,
		.set = s390_compat_last_break_set,
	},
	{
		.core_note_type = NT_S390_TDB,
		.n = 1,
		.size = 256,
		.align = 1,
		.get = s390_tdb_get,
		.set = s390_tdb_set,
	},
	{
		.core_note_type = NT_S390_VXRS_LOW,
		.n = __NUM_VXRS_LOW,
		.size = sizeof(__u64),
		.align = sizeof(__u64),
		.get = s390_vxrs_low_get,
		.set = s390_vxrs_low_set,
	},
	{
		.core_note_type = NT_S390_VXRS_HIGH,
		.n = __NUM_VXRS_HIGH,
		.size = sizeof(__vector128),
		.align = sizeof(__vector128),
		.get = s390_vxrs_high_get,
		.set = s390_vxrs_high_set,
	},
	{
		.core_note_type = NT_S390_HIGH_GPRS,
		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
		.size = sizeof(compat_long_t),
		.align = sizeof(compat_long_t),
		.get = s390_compat_regs_high_get,
		.set = s390_compat_regs_high_set,
	},
	{
		.core_note_type = NT_S390_GS_CB,
		.n = sizeof(struct gs_cb) / sizeof(__u64),
		.size = sizeof(__u64),
		.align = sizeof(__u64),
		.get = s390_gs_cb_get,
		.set = s390_gs_cb_set,
	},
};

static const struct user_regset_view user_s390_compat_view = {
	.name = "s390",
	.e_machine = EM_S390,
	.regsets = s390_compat_regsets,
	.n = ARRAY_SIZE(s390_compat_regsets)
};
#endif

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
	if (test_tsk_thread_flag(task, TIF_31BIT))
		return &user_s390_compat_view;
#endif
	return &user_s390_view;
}

static const char *gpr_names[NUM_GPRS] = {
	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
};

unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
{
	if (offset >= NUM_GPRS)
		return 0;
	return regs->gprs[offset];
}

int regs_query_register_offset(const char *name)
{
	unsigned long offset;

	if (!name || *name != 'r')
		return -EINVAL;
	if (kstrtoul(name + 1, 10, &offset))
		return -EINVAL;
	if (offset >= NUM_GPRS)
		return -EINVAL;
	return offset;
}

const char *regs_query_register_name(unsigned int offset)
{
	if (offset >= NUM_GPRS)
		return NULL;
	return gpr_names[offset];
}

static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
	unsigned long ksp = kernel_stack_pointer(regs);

	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
}

/**
 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 * @regs:pt_regs which contains kernel stack pointer.
 * @n:stack entry number.
 *
 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
 * this returns 0.
 */
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
	unsigned long addr;

	addr = kernel_stack_pointer(regs) + n * sizeof(long);
	if (!regs_within_kernel_stack(regs, addr))
		return 0;
	return *(unsigned long *)addr;
}