summaryrefslogtreecommitdiff
path: root/gdb/s390-linux-nat.c
blob: fc3917d30be18cf4f6959d97bb01800bdec4536e (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
/* S390 native-dependent code for GDB, the GNU debugger.
   Copyright (C) 2001-2023 Free Software Foundation, Inc.

   Contributed by D.J. Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
   for IBM Deutschland Entwicklung GmbH, IBM Corporation.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "regcache.h"
#include "inferior.h"
#include "target.h"
#include "linux-nat.h"
#include "auxv.h"
#include "gregset.h"
#include "regset.h"
#include "nat/linux-ptrace.h"
#include "gdbcmd.h"
#include "gdbarch.h"

#include "s390-tdep.h"
#include "s390-linux-tdep.h"
#include "elf/common.h"

#include <asm/ptrace.h>
#include "nat/gdb_ptrace.h"
#include <asm/types.h>
#include <sys/procfs.h>
#include <sys/ucontext.h>
#include <elf.h>
#include <algorithm>
#include "inf-ptrace.h"
#include "linux-tdep.h"

/* Per-thread arch-specific data.  */

struct arch_lwp_info
{
  /* Non-zero if the thread's PER info must be re-written.  */
  int per_info_changed;
};

static int have_regset_last_break = 0;
static int have_regset_system_call = 0;
static int have_regset_tdb = 0;
static int have_regset_vxrs = 0;
static int have_regset_gs = 0;

/* Register map for 32-bit executables running under a 64-bit
   kernel.  */

#ifdef __s390x__
static const struct regcache_map_entry s390_64_regmap_gregset[] =
  {
    /* Skip PSWM and PSWA, since they must be handled specially.  */
    { 2, REGCACHE_MAP_SKIP, 8 },
    { 1, S390_R0_UPPER_REGNUM, 4 }, { 1, S390_R0_REGNUM, 4 },
    { 1, S390_R1_UPPER_REGNUM, 4 }, { 1, S390_R1_REGNUM, 4 },
    { 1, S390_R2_UPPER_REGNUM, 4 }, { 1, S390_R2_REGNUM, 4 },
    { 1, S390_R3_UPPER_REGNUM, 4 }, { 1, S390_R3_REGNUM, 4 },
    { 1, S390_R4_UPPER_REGNUM, 4 }, { 1, S390_R4_REGNUM, 4 },
    { 1, S390_R5_UPPER_REGNUM, 4 }, { 1, S390_R5_REGNUM, 4 },
    { 1, S390_R6_UPPER_REGNUM, 4 }, { 1, S390_R6_REGNUM, 4 },
    { 1, S390_R7_UPPER_REGNUM, 4 }, { 1, S390_R7_REGNUM, 4 },
    { 1, S390_R8_UPPER_REGNUM, 4 }, { 1, S390_R8_REGNUM, 4 },
    { 1, S390_R9_UPPER_REGNUM, 4 }, { 1, S390_R9_REGNUM, 4 },
    { 1, S390_R10_UPPER_REGNUM, 4 }, { 1, S390_R10_REGNUM, 4 },
    { 1, S390_R11_UPPER_REGNUM, 4 }, { 1, S390_R11_REGNUM, 4 },
    { 1, S390_R12_UPPER_REGNUM, 4 }, { 1, S390_R12_REGNUM, 4 },
    { 1, S390_R13_UPPER_REGNUM, 4 }, { 1, S390_R13_REGNUM, 4 },
    { 1, S390_R14_UPPER_REGNUM, 4 }, { 1, S390_R14_REGNUM, 4 },
    { 1, S390_R15_UPPER_REGNUM, 4 }, { 1, S390_R15_REGNUM, 4 },
    { 16, S390_A0_REGNUM, 4 },
    { 1, REGCACHE_MAP_SKIP, 4 }, { 1, S390_ORIG_R2_REGNUM, 4 },
    { 0 }
  };

static const struct regset s390_64_gregset =
  {
    s390_64_regmap_gregset,
    regcache_supply_regset,
    regcache_collect_regset
  };

#define S390_PSWM_OFFSET 0
#define S390_PSWA_OFFSET 8
#endif

/* PER-event mask bits and PER control bits (CR9).  */

#define PER_BIT(n)			(1UL << (63 - (n)))
#define PER_EVENT_BRANCH		PER_BIT (32)
#define PER_EVENT_IFETCH		PER_BIT (33)
#define PER_EVENT_STORE			PER_BIT (34)
#define PER_EVENT_NULLIFICATION		PER_BIT (39)
#define PER_CONTROL_BRANCH_ADDRESS	PER_BIT (40)
#define PER_CONTROL_SUSPENSION		PER_BIT (41)
#define PER_CONTROL_ALTERATION		PER_BIT (42)

class s390_linux_nat_target final : public linux_nat_target
{
public:
  /* Add our register access methods.  */
  void fetch_registers (struct regcache *, int) override;
  void store_registers (struct regcache *, int) override;

  /* Add our watchpoint methods.  */
  int can_use_hw_breakpoint (enum bptype, int, int) override;
  int insert_hw_breakpoint (struct gdbarch *, struct bp_target_info *)
    override;
  int remove_hw_breakpoint (struct gdbarch *, struct bp_target_info *)
    override;
  int region_ok_for_hw_watchpoint (CORE_ADDR, int) override;
  bool stopped_by_watchpoint () override;
  int insert_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
			 struct expression *) override;
  int remove_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
			 struct expression *) override;

  /* Detect target architecture.  */
  const struct target_desc *read_description () override;
  int auxv_parse (const gdb_byte **readptr,
		  const gdb_byte *endptr, CORE_ADDR *typep, CORE_ADDR *valp)
    override;

  /* Override linux_nat_target low methods.  */
  void low_new_thread (struct lwp_info *lp) override;
  void low_delete_thread (struct arch_lwp_info *lp) override;
  void low_prepare_to_resume (struct lwp_info *lp) override;
  void low_new_fork (struct lwp_info *parent, pid_t child_pid) override;
  void low_forget_process (pid_t pid) override;
};

static s390_linux_nat_target the_s390_linux_nat_target;

/* Fill GDB's register array with the general-purpose register values
   in *REGP.

   When debugging a 32-bit executable running under a 64-bit kernel,
   we have to fix up the 64-bit registers we get from the kernel to
   make them look like 32-bit registers.  */

void
supply_gregset (struct regcache *regcache, const gregset_t *regp)
{
#ifdef __s390x__
  struct gdbarch *gdbarch = regcache->arch ();
  if (gdbarch_ptr_bit (gdbarch) == 32)
    {
      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
      ULONGEST pswm, pswa;
      gdb_byte buf[4];

      regcache_supply_regset (&s390_64_gregset, regcache, -1,
			      regp, sizeof (gregset_t));
      pswm = extract_unsigned_integer ((const gdb_byte *) regp
				       + S390_PSWM_OFFSET, 8, byte_order);
      pswa = extract_unsigned_integer ((const gdb_byte *) regp
				       + S390_PSWA_OFFSET, 8, byte_order);
      store_unsigned_integer (buf, 4, byte_order, (pswm >> 32) | 0x80000);
      regcache->raw_supply (S390_PSWM_REGNUM, buf);
      store_unsigned_integer (buf, 4, byte_order,
			      (pswa & 0x7fffffff) | (pswm & 0x80000000));
      regcache->raw_supply (S390_PSWA_REGNUM, buf);
      return;
    }
#endif

  regcache_supply_regset (&s390_gregset, regcache, -1, regp,
			  sizeof (gregset_t));
}

/* Fill register REGNO (if it is a general-purpose register) in
   *REGP with the value in GDB's register array.  If REGNO is -1,
   do this for all registers.  */

void
fill_gregset (const struct regcache *regcache, gregset_t *regp, int regno)
{
#ifdef __s390x__
  struct gdbarch *gdbarch = regcache->arch ();
  if (gdbarch_ptr_bit (gdbarch) == 32)
    {
      regcache_collect_regset (&s390_64_gregset, regcache, regno,
			       regp, sizeof (gregset_t));

      if (regno == -1
	  || regno == S390_PSWM_REGNUM || regno == S390_PSWA_REGNUM)
	{
	  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
	  ULONGEST pswa, pswm;
	  gdb_byte buf[4];
	  gdb_byte *pswm_p = (gdb_byte *) regp + S390_PSWM_OFFSET;
	  gdb_byte *pswa_p = (gdb_byte *) regp + S390_PSWA_OFFSET;

	  pswm = extract_unsigned_integer (pswm_p, 8, byte_order);

	  if (regno == -1 || regno == S390_PSWM_REGNUM)
	    {
	      pswm &= 0x80000000;
	      regcache->raw_collect (S390_PSWM_REGNUM, buf);
	      pswm |= (extract_unsigned_integer (buf, 4, byte_order)
		       & 0xfff7ffff) << 32;
	    }

	  if (regno == -1 || regno == S390_PSWA_REGNUM)
	    {
	      regcache->raw_collect (S390_PSWA_REGNUM, buf);
	      pswa = extract_unsigned_integer (buf, 4, byte_order);
	      pswm ^= (pswm ^ pswa) & 0x80000000;
	      pswa &= 0x7fffffff;
	      store_unsigned_integer (pswa_p, 8, byte_order, pswa);
	    }

	  store_unsigned_integer (pswm_p, 8, byte_order, pswm);
	}
      return;
    }
#endif

  regcache_collect_regset (&s390_gregset, regcache, regno, regp,
			   sizeof (gregset_t));
}

/* Fill GDB's register array with the floating-point register values
   in *REGP.  */
void
supply_fpregset (struct regcache *regcache, const fpregset_t *regp)
{
  regcache_supply_regset (&s390_fpregset, regcache, -1, regp,
			  sizeof (fpregset_t));
}

/* Fill register REGNO (if it is a general-purpose register) in
   *REGP with the value in GDB's register array.  If REGNO is -1,
   do this for all registers.  */
void
fill_fpregset (const struct regcache *regcache, fpregset_t *regp, int regno)
{
  regcache_collect_regset (&s390_fpregset, regcache, regno, regp,
			   sizeof (fpregset_t));
}

/* Find the TID for the current inferior thread to use with ptrace.  */
static int
s390_inferior_tid (void)
{
  /* GNU/Linux LWP ID's are process ID's.  */
  int tid = inferior_ptid.lwp ();
  if (tid == 0)
    tid = inferior_ptid.pid (); /* Not a threaded program.  */

  return tid;
}

/* Fetch all general-purpose registers from process/thread TID and
   store their values in GDB's register cache.  */
static void
fetch_regs (struct regcache *regcache, int tid)
{
  gregset_t regs;
  ptrace_area parea;

  parea.len = sizeof (regs);
  parea.process_addr = (addr_t) &regs;
  parea.kernel_addr = offsetof (struct user_regs_struct, psw);
  if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't get registers"));

  supply_gregset (regcache, (const gregset_t *) &regs);
}

/* Store all valid general-purpose registers in GDB's register cache
   into the process/thread specified by TID.  */
static void
store_regs (const struct regcache *regcache, int tid, int regnum)
{
  gregset_t regs;
  ptrace_area parea;

  parea.len = sizeof (regs);
  parea.process_addr = (addr_t) &regs;
  parea.kernel_addr = offsetof (struct user_regs_struct, psw);
  if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't get registers"));

  fill_gregset (regcache, &regs, regnum);

  if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't write registers"));
}

/* Fetch all floating-point registers from process/thread TID and store
   their values in GDB's register cache.  */
static void
fetch_fpregs (struct regcache *regcache, int tid)
{
  fpregset_t fpregs;
  ptrace_area parea;

  parea.len = sizeof (fpregs);
  parea.process_addr = (addr_t) &fpregs;
  parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
  if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't get floating point status"));

  supply_fpregset (regcache, (const fpregset_t *) &fpregs);
}

/* Store all valid floating-point registers in GDB's register cache
   into the process/thread specified by TID.  */
static void
store_fpregs (const struct regcache *regcache, int tid, int regnum)
{
  fpregset_t fpregs;
  ptrace_area parea;

  parea.len = sizeof (fpregs);
  parea.process_addr = (addr_t) &fpregs;
  parea.kernel_addr = offsetof (struct user_regs_struct, fp_regs);
  if (ptrace (PTRACE_PEEKUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't get floating point status"));

  fill_fpregset (regcache, &fpregs, regnum);

  if (ptrace (PTRACE_POKEUSR_AREA, tid, (long) &parea, 0) < 0)
    perror_with_name (_("Couldn't write floating point status"));
}

/* Fetch all registers in the kernel's register set whose number is
   REGSET_ID, whose size is REGSIZE, and whose layout is described by
   REGSET, from process/thread TID and store their values in GDB's
   register cache.  */
static void
fetch_regset (struct regcache *regcache, int tid,
	      int regset_id, int regsize, const struct regset *regset)
{
  void *buf = alloca (regsize);
  struct iovec iov;

  iov.iov_base = buf;
  iov.iov_len = regsize;

  if (ptrace (PTRACE_GETREGSET, tid, (long) regset_id, (long) &iov) < 0)
    {
      if (errno == ENODATA)
	regcache_supply_regset (regset, regcache, -1, NULL, regsize);
      else
	perror_with_name (_("Couldn't get register set"));
    }
  else
    regcache_supply_regset (regset, regcache, -1, buf, regsize);
}

/* Store all registers in the kernel's register set whose number is
   REGSET_ID, whose size is REGSIZE, and whose layout is described by
   REGSET, from GDB's register cache back to process/thread TID.  */
static void
store_regset (struct regcache *regcache, int tid,
	      int regset_id, int regsize, const struct regset *regset)
{
  void *buf = alloca (regsize);
  struct iovec iov;

  iov.iov_base = buf;
  iov.iov_len = regsize;

  if (ptrace (PTRACE_GETREGSET, tid, (long) regset_id, (long) &iov) < 0)
    perror_with_name (_("Couldn't get register set"));

  regcache_collect_regset (regset, regcache, -1, buf, regsize);

  if (ptrace (PTRACE_SETREGSET, tid, (long) regset_id, (long) &iov) < 0)
    perror_with_name (_("Couldn't set register set"));
}

/* Check whether the kernel provides a register set with number REGSET
   of size REGSIZE for process/thread TID.  */
static int
check_regset (int tid, int regset, int regsize)
{
  void *buf = alloca (regsize);
  struct iovec iov;

  iov.iov_base = buf;
  iov.iov_len = regsize;

  if (ptrace (PTRACE_GETREGSET, tid, (long) regset, (long) &iov) >= 0
      || errno == ENODATA)
    return 1;
  return 0;
}

/* Fetch register REGNUM from the child process.  If REGNUM is -1, do
   this for all registers.  */
void
s390_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
{
  pid_t tid = get_ptrace_pid (regcache->ptid ());

  if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
    fetch_regs (regcache, tid);

  if (regnum == -1 || S390_IS_FPREGSET_REGNUM (regnum))
    fetch_fpregs (regcache, tid);

  if (have_regset_last_break)
    if (regnum == -1 || regnum == S390_LAST_BREAK_REGNUM)
      fetch_regset (regcache, tid, NT_S390_LAST_BREAK, 8,
		    (gdbarch_ptr_bit (regcache->arch ()) == 32
		     ? &s390_last_break_regset : &s390x_last_break_regset));

  if (have_regset_system_call)
    if (regnum == -1 || regnum == S390_SYSTEM_CALL_REGNUM)
      fetch_regset (regcache, tid, NT_S390_SYSTEM_CALL, 4,
		    &s390_system_call_regset);

  if (have_regset_tdb)
    if (regnum == -1 || S390_IS_TDBREGSET_REGNUM (regnum))
      fetch_regset (regcache, tid, NT_S390_TDB, s390_sizeof_tdbregset,
		    &s390_tdb_regset);

  if (have_regset_vxrs)
    {
      if (regnum == -1 || (regnum >= S390_V0_LOWER_REGNUM
			   && regnum <= S390_V15_LOWER_REGNUM))
	fetch_regset (regcache, tid, NT_S390_VXRS_LOW, 16 * 8,
		      &s390_vxrs_low_regset);
      if (regnum == -1 || (regnum >= S390_V16_REGNUM
			   && regnum <= S390_V31_REGNUM))
	fetch_regset (regcache, tid, NT_S390_VXRS_HIGH, 16 * 16,
		      &s390_vxrs_high_regset);
    }

  if (have_regset_gs)
    {
      if (regnum == -1 || (regnum >= S390_GSD_REGNUM
			   && regnum <= S390_GSEPLA_REGNUM))
	fetch_regset (regcache, tid, NT_S390_GS_CB, 4 * 8,
		      &s390_gs_regset);
      if (regnum == -1 || (regnum >= S390_BC_GSD_REGNUM
			   && regnum <= S390_BC_GSEPLA_REGNUM))
	fetch_regset (regcache, tid, NT_S390_GS_BC, 4 * 8,
		      &s390_gsbc_regset);
    }
}

/* Store register REGNUM back into the child process.  If REGNUM is
   -1, do this for all registers.  */
void
s390_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
{
  pid_t tid = get_ptrace_pid (regcache->ptid ());

  if (regnum == -1 || S390_IS_GREGSET_REGNUM (regnum))
    store_regs (regcache, tid, regnum);

  if (regnum == -1 || S390_IS_FPREGSET_REGNUM (regnum))
    store_fpregs (regcache, tid, regnum);

  /* S390_LAST_BREAK_REGNUM is read-only.  */

  if (have_regset_system_call)
    if (regnum == -1 || regnum == S390_SYSTEM_CALL_REGNUM)
      store_regset (regcache, tid, NT_S390_SYSTEM_CALL, 4,
		    &s390_system_call_regset);

  if (have_regset_vxrs)
    {
      if (regnum == -1 || (regnum >= S390_V0_LOWER_REGNUM
			   && regnum <= S390_V15_LOWER_REGNUM))
	store_regset (regcache, tid, NT_S390_VXRS_LOW, 16 * 8,
		      &s390_vxrs_low_regset);
      if (regnum == -1 || (regnum >= S390_V16_REGNUM
			   && regnum <= S390_V31_REGNUM))
	store_regset (regcache, tid, NT_S390_VXRS_HIGH, 16 * 16,
		      &s390_vxrs_high_regset);
    }
}


/* Hardware-assisted watchpoint handling.  */

/* For each process we maintain a list of all currently active
   watchpoints, in order to properly handle watchpoint removal.

   The only thing we actually need is the total address space area
   spanned by the watchpoints.  */

struct watch_area
{
  CORE_ADDR lo_addr;
  CORE_ADDR hi_addr;
};

/* Hardware debug state.  */

struct s390_debug_reg_state
{
  std::vector<watch_area> watch_areas;
  std::vector<watch_area> break_areas;
};

/* Per-process data.  */

struct s390_process_info
{
  struct s390_process_info *next = nullptr;
  pid_t pid = 0;
  struct s390_debug_reg_state state;
};

static struct s390_process_info *s390_process_list = NULL;

/* Find process data for process PID.  */

static struct s390_process_info *
s390_find_process_pid (pid_t pid)
{
  struct s390_process_info *proc;

  for (proc = s390_process_list; proc; proc = proc->next)
    if (proc->pid == pid)
      return proc;

  return NULL;
}

/* Add process data for process PID.  Returns newly allocated info
   object.  */

static struct s390_process_info *
s390_add_process (pid_t pid)
{
  struct s390_process_info *proc = new struct s390_process_info;

  proc->pid = pid;
  proc->next = s390_process_list;
  s390_process_list = proc;

  return proc;
}

/* Get data specific info for process PID, creating it if necessary.
   Never returns NULL.  */

static struct s390_process_info *
s390_process_info_get (pid_t pid)
{
  struct s390_process_info *proc;

  proc = s390_find_process_pid (pid);
  if (proc == NULL)
    proc = s390_add_process (pid);

  return proc;
}

/* Get hardware debug state for process PID.  */

static struct s390_debug_reg_state *
s390_get_debug_reg_state (pid_t pid)
{
  return &s390_process_info_get (pid)->state;
}

/* Called whenever GDB is no longer debugging process PID.  It deletes
   data structures that keep track of hardware debug state.  */

void
s390_linux_nat_target::low_forget_process (pid_t pid)
{
  struct s390_process_info *proc, **proc_link;

  proc = s390_process_list;
  proc_link = &s390_process_list;

  while (proc != NULL)
    {
      if (proc->pid == pid)
	{
	  *proc_link = proc->next;
	  delete proc;
	  return;
	}

      proc_link = &proc->next;
      proc = *proc_link;
    }
}

/* linux_nat_new_fork hook.   */

void
s390_linux_nat_target::low_new_fork (struct lwp_info *parent, pid_t child_pid)
{
  pid_t parent_pid;
  struct s390_debug_reg_state *parent_state;
  struct s390_debug_reg_state *child_state;

  /* NULL means no watchpoint has ever been set in the parent.  In
     that case, there's nothing to do.  */
  if (lwp_arch_private_info (parent) == NULL)
    return;

  /* GDB core assumes the child inherits the watchpoints/hw breakpoints of
     the parent.  So copy the debug state from parent to child.  */

  parent_pid = parent->ptid.pid ();
  parent_state = s390_get_debug_reg_state (parent_pid);
  child_state = s390_get_debug_reg_state (child_pid);

  child_state->watch_areas = parent_state->watch_areas;
  child_state->break_areas = parent_state->break_areas;
}

/* Dump PER state.  */

static void
s390_show_debug_regs (int tid, const char *where)
{
  per_struct per_info;
  ptrace_area parea;

  parea.len = sizeof (per_info);
  parea.process_addr = (addr_t) &per_info;
  parea.kernel_addr = offsetof (struct user_regs_struct, per_info);

  if (ptrace (PTRACE_PEEKUSR_AREA, tid, &parea, 0) < 0)
    perror_with_name (_("Couldn't retrieve debug regs"));

  debug_printf ("PER (debug) state for %d -- %s\n"
		"  cr9-11: %lx %lx %lx\n"
		"  start, end: %lx %lx\n"
		"  code/ATMID: %x  address: %lx  PAID: %x\n",
		tid,
		where,
		per_info.control_regs.words.cr[0],
		per_info.control_regs.words.cr[1],
		per_info.control_regs.words.cr[2],
		per_info.starting_addr,
		per_info.ending_addr,
		per_info.lowcore.words.perc_atmid,
		per_info.lowcore.words.address,
		per_info.lowcore.words.access_id);
}

bool
s390_linux_nat_target::stopped_by_watchpoint ()
{
  struct s390_debug_reg_state *state
    = s390_get_debug_reg_state (inferior_ptid.pid ());
  per_lowcore_bits per_lowcore;
  ptrace_area parea;

  if (show_debug_regs)
    s390_show_debug_regs (s390_inferior_tid (), "stop");

  /* Speed up common case.  */
  if (state->watch_areas.empty ())
    return false;

  siginfo_t siginfo;
  if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
    return false;
  if (siginfo.si_signo != SIGTRAP
      || (siginfo.si_code & 0xffff) != TRAP_HWBKPT)
    return false;

  parea.len = sizeof (per_lowcore);
  parea.process_addr = (addr_t) & per_lowcore;
  parea.kernel_addr = offsetof (struct user_regs_struct, per_info.lowcore);
  if (ptrace (PTRACE_PEEKUSR_AREA, s390_inferior_tid (), &parea, 0) < 0)
    perror_with_name (_("Couldn't retrieve watchpoint status"));

  bool result = (per_lowcore.perc_storage_alteration == 1
		 && per_lowcore.perc_store_real_address == 0);

  return result;
}

/* Each time before resuming a thread, update its PER info.  */

void
s390_linux_nat_target::low_prepare_to_resume (struct lwp_info *lp)
{
  int tid;
  pid_t pid = ptid_of_lwp (lp).pid ();

  per_struct per_info;
  ptrace_area parea;

  CORE_ADDR watch_lo_addr = (CORE_ADDR)-1, watch_hi_addr = 0;
  struct arch_lwp_info *lp_priv = lwp_arch_private_info (lp);
  struct s390_debug_reg_state *state = s390_get_debug_reg_state (pid);
  int step = lwp_is_stepping (lp);

  /* Nothing to do if there was never any PER info for this thread.  */
  if (lp_priv == NULL)
    return;

  /* If PER info has changed, update it.  When single-stepping, disable
     hardware breakpoints (if any).  Otherwise we're done.  */
  if (!lp_priv->per_info_changed)
    {
      if (!step || state->break_areas.empty ())
	return;
    }

  lp_priv->per_info_changed = 0;

  tid = ptid_of_lwp (lp).lwp ();
  if (tid == 0)
    tid = pid;

  parea.len = sizeof (per_info);
  parea.process_addr = (addr_t) & per_info;
  parea.kernel_addr = offsetof (struct user_regs_struct, per_info);

  /* Clear PER info, but adjust the single_step field (used by older
     kernels only).  */
  memset (&per_info, 0, sizeof (per_info));
  per_info.single_step = (step != 0);

  if (!state->watch_areas.empty ())
    {
      for (const auto &area : state->watch_areas)
	{
	  watch_lo_addr = std::min (watch_lo_addr, area.lo_addr);
	  watch_hi_addr = std::max (watch_hi_addr, area.hi_addr);
	}

      /* Enable storage-alteration events.  */
      per_info.control_regs.words.cr[0] |= (PER_EVENT_STORE
					    | PER_CONTROL_ALTERATION);
    }

  if (!state->break_areas.empty ())
    {
      /* Don't install hardware breakpoints while single-stepping, since
	 our PER settings (e.g. the nullification bit) might then conflict
	 with the kernel's.  But re-install them afterwards.  */
      if (step)
	lp_priv->per_info_changed = 1;
      else
	{
	  for (const auto &area : state->break_areas)
	    {
	      watch_lo_addr = std::min (watch_lo_addr, area.lo_addr);
	      watch_hi_addr = std::max (watch_hi_addr, area.hi_addr);
	    }

	  /* If there's just one breakpoint, enable instruction-fetching
	     nullification events for the breakpoint address (fast).
	     Otherwise stop after any instruction within the PER area and
	     after any branch into it (slow).  */
	  if (watch_hi_addr == watch_lo_addr)
	    per_info.control_regs.words.cr[0] |= (PER_EVENT_NULLIFICATION
						  | PER_EVENT_IFETCH);
	  else
	    {
	      /* The PER area must include the instruction before the
		 first breakpoint address.  */
	      watch_lo_addr = watch_lo_addr > 6 ? watch_lo_addr - 6 : 0;
	      per_info.control_regs.words.cr[0]
		|= (PER_EVENT_BRANCH
		    | PER_EVENT_IFETCH
		    | PER_CONTROL_BRANCH_ADDRESS);
	    }
	}
    }
  per_info.starting_addr = watch_lo_addr;
  per_info.ending_addr = watch_hi_addr;

  if (ptrace (PTRACE_POKEUSR_AREA, tid, &parea, 0) < 0)
    perror_with_name (_("Couldn't modify watchpoint status"));

  if (show_debug_regs)
    s390_show_debug_regs (tid, "resume");
}

/* Mark the PER info as changed, so the next resume will update it.  */

static void
s390_mark_per_info_changed (struct lwp_info *lp)
{
  if (lwp_arch_private_info (lp) == NULL)
    lwp_set_arch_private_info (lp, XCNEW (struct arch_lwp_info));

  lwp_arch_private_info (lp)->per_info_changed = 1;
}

/* When attaching to a new thread, mark its PER info as changed.  */

void
s390_linux_nat_target::low_new_thread (struct lwp_info *lp)
{
  s390_mark_per_info_changed (lp);
}

/* Function to call when a thread is being deleted.  */

void
s390_linux_nat_target::low_delete_thread (struct arch_lwp_info *arch_lwp)
{
  xfree (arch_lwp);
}

/* Iterator callback for s390_refresh_per_info.  */

static int
s390_refresh_per_info_cb (struct lwp_info *lp)
{
  s390_mark_per_info_changed (lp);

  if (!lwp_is_stopped (lp))
    linux_stop_lwp (lp);
  return 0;
}

/* Make sure that threads are stopped and mark PER info as changed.  */

static int
s390_refresh_per_info (void)
{
  ptid_t pid_ptid = ptid_t (current_lwp_ptid ().pid ());

  iterate_over_lwps (pid_ptid, s390_refresh_per_info_cb);
  return 0;
}

int
s390_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
					  enum target_hw_bp_type type,
					  struct expression *cond)
{
  watch_area area;
  struct s390_debug_reg_state *state
    = s390_get_debug_reg_state (inferior_ptid.pid ());

  area.lo_addr = addr;
  area.hi_addr = addr + len - 1;
  state->watch_areas.push_back (area);

  return s390_refresh_per_info ();
}

int
s390_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
					  enum target_hw_bp_type type,
					  struct expression *cond)
{
  unsigned ix;
  struct s390_debug_reg_state *state
    = s390_get_debug_reg_state (inferior_ptid.pid ());

  for (ix = 0; ix < state->watch_areas.size (); ix++)
    {
      watch_area &area = state->watch_areas[ix];
      if (area.lo_addr == addr && area.hi_addr == addr + len - 1)
	{
	  unordered_remove (state->watch_areas, ix);
	  return s390_refresh_per_info ();
	}
    }

  gdb_printf (gdb_stderr,
	      "Attempt to remove nonexistent watchpoint.\n");
  return -1;
}

/* Implement the "can_use_hw_breakpoint" target_ops method. */

int
s390_linux_nat_target::can_use_hw_breakpoint (enum bptype type,
					      int cnt, int othertype)
{
  if (type == bp_hardware_watchpoint || type == bp_hardware_breakpoint)
    return 1;
  return 0;
}

/* Implement the "insert_hw_breakpoint" target_ops method.  */

int
s390_linux_nat_target::insert_hw_breakpoint (struct gdbarch *gdbarch,
					     struct bp_target_info *bp_tgt)
{
  watch_area area;
  struct s390_debug_reg_state *state;

  area.lo_addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
  area.hi_addr = area.lo_addr;
  state = s390_get_debug_reg_state (inferior_ptid.pid ());
  state->break_areas.push_back (area);

  return s390_refresh_per_info ();
}

/* Implement the "remove_hw_breakpoint" target_ops method.  */

int
s390_linux_nat_target::remove_hw_breakpoint (struct gdbarch *gdbarch,
					     struct bp_target_info *bp_tgt)
{
  unsigned ix;
  struct s390_debug_reg_state *state;

  state = s390_get_debug_reg_state (inferior_ptid.pid ());
  for (ix = 0; state->break_areas.size (); ix++)
    {
      watch_area &area = state->break_areas[ix];
      if (area.lo_addr == bp_tgt->placed_address)
	{
	  unordered_remove (state->break_areas, ix);
	  return s390_refresh_per_info ();
	}
    }

  gdb_printf (gdb_stderr,
	      "Attempt to remove nonexistent breakpoint.\n");
  return -1;
}

int
s390_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int cnt)
{
  return 1;
}

static int
s390_target_wordsize (void)
{
  int wordsize = 4;

  /* Check for 64-bit inferior process.  This is the case when the host is
     64-bit, and in addition bit 32 of the PSW mask is set.  */
#ifdef __s390x__
  long pswm;

  errno = 0;
  pswm = (long) ptrace (PTRACE_PEEKUSER, s390_inferior_tid (), PT_PSWMASK, 0);
  if (errno == 0 && (pswm & 0x100000000ul) != 0)
    wordsize = 8;
#endif

  return wordsize;
}

int
s390_linux_nat_target::auxv_parse (const gdb_byte **readptr,
				   const gdb_byte *endptr, CORE_ADDR *typep,
				   CORE_ADDR *valp)
{
  int sizeof_auxv_field = s390_target_wordsize ();
  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
  const gdb_byte *ptr = *readptr;

  if (endptr == ptr)
    return 0;

  if (endptr - ptr < sizeof_auxv_field * 2)
    return -1;

  *typep = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
  ptr += sizeof_auxv_field;
  *valp = extract_unsigned_integer (ptr, sizeof_auxv_field, byte_order);
  ptr += sizeof_auxv_field;

  *readptr = ptr;
  return 1;
}

const struct target_desc *
s390_linux_nat_target::read_description ()
{
  int tid = inferior_ptid.pid ();

  have_regset_last_break
    = check_regset (tid, NT_S390_LAST_BREAK, 8);
  have_regset_system_call
    = check_regset (tid, NT_S390_SYSTEM_CALL, 4);

  /* If GDB itself is compiled as 64-bit, we are running on a machine in
     z/Architecture mode.  If the target is running in 64-bit addressing
     mode, report s390x architecture.  If the target is running in 31-bit
     addressing mode, but the kernel supports using 64-bit registers in
     that mode, report s390 architecture with 64-bit GPRs.  */
#ifdef __s390x__
  {
    CORE_ADDR hwcap = linux_get_hwcap ();

    have_regset_tdb = (hwcap & HWCAP_S390_TE)
      && check_regset (tid, NT_S390_TDB, s390_sizeof_tdbregset);

    have_regset_vxrs = (hwcap & HWCAP_S390_VX)
      && check_regset (tid, NT_S390_VXRS_LOW, 16 * 8)
      && check_regset (tid, NT_S390_VXRS_HIGH, 16 * 16);

    have_regset_gs = (hwcap & HWCAP_S390_GS)
      && check_regset (tid, NT_S390_GS_CB, 4 * 8)
      && check_regset (tid, NT_S390_GS_BC, 4 * 8);

    if (s390_target_wordsize () == 8)
      return (have_regset_gs ? tdesc_s390x_gs_linux64 :
	      have_regset_vxrs ?
	      (have_regset_tdb ? tdesc_s390x_tevx_linux64 :
	       tdesc_s390x_vx_linux64) :
	      have_regset_tdb ? tdesc_s390x_te_linux64 :
	      have_regset_system_call ? tdesc_s390x_linux64v2 :
	      have_regset_last_break ? tdesc_s390x_linux64v1 :
	      tdesc_s390x_linux64);

    if (hwcap & HWCAP_S390_HIGH_GPRS)
      return (have_regset_gs ? tdesc_s390_gs_linux64 :
	      have_regset_vxrs ?
	      (have_regset_tdb ? tdesc_s390_tevx_linux64 :
	       tdesc_s390_vx_linux64) :
	      have_regset_tdb ? tdesc_s390_te_linux64 :
	      have_regset_system_call ? tdesc_s390_linux64v2 :
	      have_regset_last_break ? tdesc_s390_linux64v1 :
	      tdesc_s390_linux64);
  }
#endif

  /* If GDB itself is compiled as 31-bit, or if we're running a 31-bit inferior
     on a 64-bit kernel that does not support using 64-bit registers in 31-bit
     mode, report s390 architecture with 32-bit GPRs.  */
  return (have_regset_system_call? tdesc_s390_linux32v2 :
	  have_regset_last_break? tdesc_s390_linux32v1 :
	  tdesc_s390_linux32);
}

void _initialize_s390_nat ();
void
_initialize_s390_nat ()
{
  /* Register the target.  */
  linux_target = &the_s390_linux_nat_target;
  add_inf_child_target (&the_s390_linux_nat_target);

  /* A maintenance command to enable showing the PER state.  */
  add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
			   &show_debug_regs, _("\
Set whether to show the PER (debug) hardware state."), _("\
Show whether to show the PER (debug) hardware state."), _("\
Use \"on\" to enable, \"off\" to disable.\n\
If enabled, the PER state is shown after it is changed by GDB,\n\
and when the inferior triggers a breakpoint or watchpoint."),
			   NULL,
			   NULL,
			   &maintenance_set_cmdlist,
			   &maintenance_show_cmdlist);
}