aboutsummaryrefslogtreecommitdiff
path: root/gdb/aarch64-linux-nat.c
blob: 3f5b30eaeb2b01021841d8d4ddc541c5c2b574b0 (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
/* Native-dependent code for GNU/Linux AArch64.

   Copyright (C) 2011-2017 Free Software Foundation, Inc.
   Contributed by ARM Ltd.

   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 "inferior.h"
#include "gdbcore.h"
#include "regcache.h"
#include "linux-nat.h"
#include "target-descriptions.h"
#include "auxv.h"
#include "gdbcmd.h"
#include "aarch64-tdep.h"
#include "aarch64-linux-tdep.h"
#include "aarch32-linux-nat.h"
#include "nat/aarch64-linux.h"
#include "nat/aarch64-linux-hw-point.h"

#include "elf/external.h"
#include "elf/common.h"

#include "nat/gdb_ptrace.h"
#include <sys/utsname.h>
#include <asm/ptrace.h>

#include "gregset.h"

/* Defines ps_err_e, struct ps_prochandle.  */
#include "gdb_proc_service.h"

#ifndef TRAP_HWBKPT
#define TRAP_HWBKPT 0x0004
#endif

/* Per-process data.  We don't bind this to a per-inferior registry
   because of targets like x86 GNU/Linux that need to keep track of
   processes that aren't bound to any inferior (e.g., fork children,
   checkpoints).  */

struct aarch64_process_info
{
  /* Linked list.  */
  struct aarch64_process_info *next;

  /* The process identifier.  */
  pid_t pid;

  /* Copy of aarch64 hardware debug registers.  */
  struct aarch64_debug_reg_state state;
};

static struct aarch64_process_info *aarch64_process_list = NULL;

/* Find process data for process PID.  */

static struct aarch64_process_info *
aarch64_find_process_pid (pid_t pid)
{
  struct aarch64_process_info *proc;

  for (proc = aarch64_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 aarch64_process_info *
aarch64_add_process (pid_t pid)
{
  struct aarch64_process_info *proc;

  proc = XCNEW (struct aarch64_process_info);
  proc->pid = pid;

  proc->next = aarch64_process_list;
  aarch64_process_list = proc;

  return proc;
}

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

static struct aarch64_process_info *
aarch64_process_info_get (pid_t pid)
{
  struct aarch64_process_info *proc;

  proc = aarch64_find_process_pid (pid);
  if (proc == NULL)
    proc = aarch64_add_process (pid);

  return proc;
}

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

static void
aarch64_forget_process (pid_t pid)
{
  struct aarch64_process_info *proc, **proc_link;

  proc = aarch64_process_list;
  proc_link = &aarch64_process_list;

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

	  xfree (proc);
	  return;
	}

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

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

struct aarch64_debug_reg_state *
aarch64_get_debug_reg_state (pid_t pid)
{
  return &aarch64_process_info_get (pid)->state;
}

/* Fill GDB's register array with the general-purpose register values
   from the current thread.  */

static void
fetch_gregs_from_thread (struct regcache *regcache)
{
  int ret, tid;
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  elf_gregset_t regs;
  struct iovec iovec;

  /* Make sure REGS can hold all registers contents on both aarch64
     and arm.  */
  gdb_static_assert (sizeof (regs) >= 18 * 4);

  tid = ptid_get_lwp (regcache_get_ptid (regcache));

  iovec.iov_base = &regs;
  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    iovec.iov_len = 18 * 4;
  else
    iovec.iov_len = sizeof (regs);

  ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
  if (ret < 0)
    perror_with_name (_("Unable to fetch general registers."));

  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    aarch32_gp_regcache_supply (regcache, (uint32_t *) regs, 1);
  else
    {
      int regno;

      for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
	regcache_raw_supply (regcache, regno, &regs[regno - AARCH64_X0_REGNUM]);
    }
}

/* Store to the current thread the valid general-purpose register
   values in the GDB's register array.  */

static void
store_gregs_to_thread (const struct regcache *regcache)
{
  int ret, tid;
  elf_gregset_t regs;
  struct iovec iovec;
  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  /* Make sure REGS can hold all registers contents on both aarch64
     and arm.  */
  gdb_static_assert (sizeof (regs) >= 18 * 4);
  tid = ptid_get_lwp (regcache_get_ptid (regcache));

  iovec.iov_base = &regs;
  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    iovec.iov_len = 18 * 4;
  else
    iovec.iov_len = sizeof (regs);

  ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
  if (ret < 0)
    perror_with_name (_("Unable to fetch general registers."));

  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    aarch32_gp_regcache_collect (regcache, (uint32_t *) regs, 1);
  else
    {
      int regno;

      for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
	if (REG_VALID == regcache_register_status (regcache, regno))
	  regcache_raw_collect (regcache, regno,
				&regs[regno - AARCH64_X0_REGNUM]);
    }

  ret = ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, &iovec);
  if (ret < 0)
    perror_with_name (_("Unable to store general registers."));
}

/* Fill GDB's register array with the fp/simd register values
   from the current thread.  */

static void
fetch_fpregs_from_thread (struct regcache *regcache)
{
  int ret, tid;
  elf_fpregset_t regs;
  struct iovec iovec;
  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  /* Make sure REGS can hold all VFP registers contents on both aarch64
     and arm.  */
  gdb_static_assert (sizeof regs >= VFP_REGS_SIZE);

  tid = ptid_get_lwp (regcache_get_ptid (regcache));

  iovec.iov_base = &regs;

  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    {
      iovec.iov_len = VFP_REGS_SIZE;

      ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to fetch VFP registers."));

      aarch32_vfp_regcache_supply (regcache, (gdb_byte *) &regs, 32);
    }
  else
    {
      int regno;

      iovec.iov_len = sizeof (regs);

      ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to fetch vFP/SIMD registers."));

      for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
	regcache_raw_supply (regcache, regno,
			     &regs.vregs[regno - AARCH64_V0_REGNUM]);

      regcache_raw_supply (regcache, AARCH64_FPSR_REGNUM, &regs.fpsr);
      regcache_raw_supply (regcache, AARCH64_FPCR_REGNUM, &regs.fpcr);
    }
}

/* Store to the current thread the valid fp/simd register
   values in the GDB's register array.  */

static void
store_fpregs_to_thread (const struct regcache *regcache)
{
  int ret, tid;
  elf_fpregset_t regs;
  struct iovec iovec;
  struct gdbarch *gdbarch = get_regcache_arch (regcache);

  /* Make sure REGS can hold all VFP registers contents on both aarch64
     and arm.  */
  gdb_static_assert (sizeof regs >= VFP_REGS_SIZE);
  tid = ptid_get_lwp (regcache_get_ptid (regcache));

  iovec.iov_base = &regs;

  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    {
      iovec.iov_len = VFP_REGS_SIZE;

      ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to fetch VFP registers."));

      aarch32_vfp_regcache_collect (regcache, (gdb_byte *) &regs, 32);
    }
  else
    {
      int regno;

      iovec.iov_len = sizeof (regs);

      ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to fetch FP/SIMD registers."));

      for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
	if (REG_VALID == regcache_register_status (regcache, regno))
	  regcache_raw_collect (regcache, regno,
				(char *) &regs.vregs[regno - AARCH64_V0_REGNUM]);

      if (REG_VALID == regcache_register_status (regcache, AARCH64_FPSR_REGNUM))
	regcache_raw_collect (regcache, AARCH64_FPSR_REGNUM,
			      (char *) &regs.fpsr);
      if (REG_VALID == regcache_register_status (regcache, AARCH64_FPCR_REGNUM))
	regcache_raw_collect (regcache, AARCH64_FPCR_REGNUM,
			      (char *) &regs.fpcr);
    }

  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    {
      ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_VFP, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to store VFP registers."));
    }
  else
    {
      ret = ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET, &iovec);
      if (ret < 0)
	perror_with_name (_("Unable to store FP/SIMD registers."));
    }
}

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

static void
aarch64_linux_fetch_inferior_registers (struct target_ops *ops,
					struct regcache *regcache,
					int regno)
{
  if (regno == -1)
    {
      fetch_gregs_from_thread (regcache);
      fetch_fpregs_from_thread (regcache);
    }
  else if (regno < AARCH64_V0_REGNUM)
    fetch_gregs_from_thread (regcache);
  else
    fetch_fpregs_from_thread (regcache);
}

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

static void
aarch64_linux_store_inferior_registers (struct target_ops *ops,
					struct regcache *regcache,
					int regno)
{
  if (regno == -1)
    {
      store_gregs_to_thread (regcache);
      store_fpregs_to_thread (regcache);
    }
  else if (regno < AARCH64_V0_REGNUM)
    store_gregs_to_thread (regcache);
  else
    store_fpregs_to_thread (regcache);
}

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

void
fill_gregset (const struct regcache *regcache,
	      gdb_gregset_t *gregsetp, int regno)
{
  regcache_collect_regset (&aarch64_linux_gregset, regcache,
			   regno, (gdb_byte *) gregsetp,
			   AARCH64_LINUX_SIZEOF_GREGSET);
}

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

void
supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
{
  regcache_supply_regset (&aarch64_linux_gregset, regcache, -1,
			  (const gdb_byte *) gregsetp,
			  AARCH64_LINUX_SIZEOF_GREGSET);
}

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

void
fill_fpregset (const struct regcache *regcache,
	       gdb_fpregset_t *fpregsetp, int regno)
{
  regcache_collect_regset (&aarch64_linux_fpregset, regcache,
			   regno, (gdb_byte *) fpregsetp,
			   AARCH64_LINUX_SIZEOF_FPREGSET);
}

/* Fill GDB's register array with the floating-point register values
   in *FPREGSETP.  */

void
supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
{
  regcache_supply_regset (&aarch64_linux_fpregset, regcache, -1,
			  (const gdb_byte *) fpregsetp,
			  AARCH64_LINUX_SIZEOF_FPREGSET);
}

/* linux_nat_new_fork hook.   */

static void
aarch64_linux_new_fork (struct lwp_info *parent, pid_t child_pid)
{
  pid_t parent_pid;
  struct aarch64_debug_reg_state *parent_state;
  struct aarch64_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 (parent->arch_private == NULL)
    return;

  /* GDB core assumes the child inherits the watchpoints/hw
     breakpoints of the parent, and will remove them all from the
     forked off process.  Copy the debug registers mirrors into the
     new process so that all breakpoints and watchpoints can be
     removed together.  */

  parent_pid = ptid_get_pid (parent->ptid);
  parent_state = aarch64_get_debug_reg_state (parent_pid);
  child_state = aarch64_get_debug_reg_state (child_pid);
  *child_state = *parent_state;
}


/* Called by libthread_db.  Returns a pointer to the thread local
   storage (or its descriptor).  */

ps_err_e
ps_get_thread_area (struct ps_prochandle *ph,
		    lwpid_t lwpid, int idx, void **base)
{
  int is_64bit_p
    = (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 64);

  return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_64bit_p);
}


static void (*super_post_startup_inferior) (struct target_ops *self,
					    ptid_t ptid);

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

static void
aarch64_linux_child_post_startup_inferior (struct target_ops *self,
					   ptid_t ptid)
{
  aarch64_forget_process (ptid_get_pid (ptid));
  aarch64_linux_get_debug_reg_capacity (ptid_get_pid (ptid));
  super_post_startup_inferior (self, ptid);
}

extern struct target_desc *tdesc_arm_with_neon;

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

static const struct target_desc *
aarch64_linux_read_description (struct target_ops *ops)
{
  int ret, tid;
  gdb_byte regbuf[VFP_REGS_SIZE];
  struct iovec iovec;

  tid = ptid_get_lwp (inferior_ptid);

  iovec.iov_base = regbuf;
  iovec.iov_len = VFP_REGS_SIZE;

  ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
  if (ret == 0)
    return tdesc_arm_with_neon;
  else
    return tdesc_aarch64;
}

/* Convert a native/host siginfo object, into/from the siginfo in the
   layout of the inferiors' architecture.  Returns true if any
   conversion was done; false otherwise.  If DIRECTION is 1, then copy
   from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
   INF.  */

static int
aarch64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
{
  struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());

  /* Is the inferior 32-bit?  If so, then do fixup the siginfo
     object.  */
  if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
    {
      if (direction == 0)
	aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,
					     native);
      else
	aarch64_siginfo_from_compat_siginfo (native,
					     (struct compat_siginfo *) inf);

      return 1;
    }

  return 0;
}

/* Returns the number of hardware watchpoints of type TYPE that we can
   set.  Value is positive if we can set CNT watchpoints, zero if
   setting watchpoints of type TYPE is not supported, and negative if
   CNT is more than the maximum number of watchpoints of type TYPE
   that we can support.  TYPE is one of bp_hardware_watchpoint,
   bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
   CNT is the number of such watchpoints used so far (including this
   one).  OTHERTYPE is non-zero if other types of watchpoints are
   currently enabled.  */

static int
aarch64_linux_can_use_hw_breakpoint (struct target_ops *self,
				     enum bptype type,
				     int cnt, int othertype)
{
  if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
      || type == bp_access_watchpoint || type == bp_watchpoint)
    {
      if (aarch64_num_wp_regs == 0)
	return 0;
    }
  else if (type == bp_hardware_breakpoint)
    {
      if (aarch64_num_bp_regs == 0)
	return 0;
    }
  else
    gdb_assert_not_reached ("unexpected breakpoint type");

  /* We always return 1 here because we don't have enough information
     about possible overlap of addresses that they want to watch.  As an
     extreme example, consider the case where all the watchpoints watch
     the same address and the same region length: then we can handle a
     virtually unlimited number of watchpoints, due to debug register
     sharing implemented via reference counts.  */
  return 1;
}

/* Insert a hardware-assisted breakpoint at BP_TGT->reqstd_address.
   Return 0 on success, -1 on failure.  */

static int
aarch64_linux_insert_hw_breakpoint (struct target_ops *self,
				    struct gdbarch *gdbarch,
				    struct bp_target_info *bp_tgt)
{
  int ret;
  CORE_ADDR addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
  int len;
  const enum target_hw_bp_type type = hw_execute;
  struct aarch64_debug_reg_state *state
    = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));

  gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);

  if (show_debug_regs)
    fprintf_unfiltered
      (gdb_stdlog,
       "insert_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
       (unsigned long) addr, len);

  ret = aarch64_handle_breakpoint (type, addr, len, 1 /* is_insert */, state);

  if (show_debug_regs)
    {
      aarch64_show_debug_reg_state (state,
				    "insert_hw_breakpoint", addr, len, type);
    }

  return ret;
}

/* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
   Return 0 on success, -1 on failure.  */

static int
aarch64_linux_remove_hw_breakpoint (struct target_ops *self,
				    struct gdbarch *gdbarch,
				    struct bp_target_info *bp_tgt)
{
  int ret;
  CORE_ADDR addr = bp_tgt->placed_address;
  int len = 4;
  const enum target_hw_bp_type type = hw_execute;
  struct aarch64_debug_reg_state *state
    = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));

  gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);

  if (show_debug_regs)
    fprintf_unfiltered
      (gdb_stdlog, "remove_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
       (unsigned long) addr, len);

  ret = aarch64_handle_breakpoint (type, addr, len, 0 /* is_insert */, state);

  if (show_debug_regs)
    {
      aarch64_show_debug_reg_state (state,
				    "remove_hw_watchpoint", addr, len, type);
    }

  return ret;
}

/* Implement the "to_insert_watchpoint" target_ops method.

   Insert a watchpoint to watch a memory region which starts at
   address ADDR and whose length is LEN bytes.  Watch memory accesses
   of the type TYPE.  Return 0 on success, -1 on failure.  */

static int
aarch64_linux_insert_watchpoint (struct target_ops *self,
				 CORE_ADDR addr, int len,
				 enum target_hw_bp_type type,
				 struct expression *cond)
{
  int ret;
  struct aarch64_debug_reg_state *state
    = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));

  if (show_debug_regs)
    fprintf_unfiltered (gdb_stdlog,
			"insert_watchpoint on entry (addr=0x%08lx, len=%d)\n",
			(unsigned long) addr, len);

  gdb_assert (type != hw_execute);

  ret = aarch64_handle_watchpoint (type, addr, len, 1 /* is_insert */, state);

  if (show_debug_regs)
    {
      aarch64_show_debug_reg_state (state,
				    "insert_watchpoint", addr, len, type);
    }

  return ret;
}

/* Implement the "to_remove_watchpoint" target_ops method.
   Remove a watchpoint that watched the memory region which starts at
   address ADDR, whose length is LEN bytes, and for accesses of the
   type TYPE.  Return 0 on success, -1 on failure.  */

static int
aarch64_linux_remove_watchpoint (struct target_ops *self,
				 CORE_ADDR addr, int len,
				 enum target_hw_bp_type type,
				 struct expression *cond)
{
  int ret;
  struct aarch64_debug_reg_state *state
    = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));

  if (show_debug_regs)
    fprintf_unfiltered (gdb_stdlog,
			"remove_watchpoint on entry (addr=0x%08lx, len=%d)\n",
			(unsigned long) addr, len);

  gdb_assert (type != hw_execute);

  ret = aarch64_handle_watchpoint (type, addr, len, 0 /* is_insert */, state);

  if (show_debug_regs)
    {
      aarch64_show_debug_reg_state (state,
				    "remove_watchpoint", addr, len, type);
    }

  return ret;
}

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

static int
aarch64_linux_region_ok_for_hw_watchpoint (struct target_ops *self,
					   CORE_ADDR addr, int len)
{
  return aarch64_linux_region_ok_for_watchpoint (addr, len);
}

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

static int
aarch64_linux_stopped_data_address (struct target_ops *target,
				    CORE_ADDR *addr_p)
{
  siginfo_t siginfo;
  int i, tid;
  struct aarch64_debug_reg_state *state;

  if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
    return 0;

  /* This must be a hardware breakpoint.  */
  if (siginfo.si_signo != SIGTRAP
      || (siginfo.si_code & 0xffff) != TRAP_HWBKPT)
    return 0;

  /* Check if the address matches any watched address.  */
  state = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
  for (i = aarch64_num_wp_regs - 1; i >= 0; --i)
    {
      const unsigned int len = aarch64_watchpoint_length (state->dr_ctrl_wp[i]);
      const CORE_ADDR addr_trap = (CORE_ADDR) siginfo.si_addr;
      const CORE_ADDR addr_watch = state->dr_addr_wp[i];

      if (state->dr_ref_count_wp[i]
	  && DR_CONTROL_ENABLED (state->dr_ctrl_wp[i])
	  && addr_trap >= addr_watch
	  && addr_trap < addr_watch + len)
	{
	  *addr_p = addr_trap;
	  return 1;
	}
    }

  return 0;
}

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

static int
aarch64_linux_stopped_by_watchpoint (struct target_ops *ops)
{
  CORE_ADDR addr;

  return aarch64_linux_stopped_data_address (ops, &addr);
}

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

static int
aarch64_linux_watchpoint_addr_within_range (struct target_ops *target,
					    CORE_ADDR addr,
					    CORE_ADDR start, int length)
{
  return start <= addr && start + length - 1 >= addr;
}

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

static int
aarch64_linux_can_do_single_step (struct target_ops *target)
{
  return 1;
}

/* Define AArch64 maintenance commands.  */

static void
add_show_debug_regs_command (void)
{
  /* A maintenance command to enable printing the internal DRi mirror
     variables.  */
  add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
			   &show_debug_regs, _("\
Set whether to show variables that mirror the AArch64 debug registers."), _("\
Show whether to show variables that mirror the AArch64 debug registers."), _("\
Use \"on\" to enable, \"off\" to disable.\n\
If enabled, the debug registers values are shown when GDB inserts\n\
or removes a hardware breakpoint or watchpoint, and when the inferior\n\
triggers a breakpoint or watchpoint."),
			   NULL,
			   NULL,
			   &maintenance_set_cmdlist,
			   &maintenance_show_cmdlist);
}

/* -Wmissing-prototypes.  */
void _initialize_aarch64_linux_nat (void);

void
_initialize_aarch64_linux_nat (void)
{
  struct target_ops *t;

  /* Fill in the generic GNU/Linux methods.  */
  t = linux_target ();

  add_show_debug_regs_command ();

  /* Add our register access methods.  */
  t->to_fetch_registers = aarch64_linux_fetch_inferior_registers;
  t->to_store_registers = aarch64_linux_store_inferior_registers;

  t->to_read_description = aarch64_linux_read_description;

  t->to_can_use_hw_breakpoint = aarch64_linux_can_use_hw_breakpoint;
  t->to_insert_hw_breakpoint = aarch64_linux_insert_hw_breakpoint;
  t->to_remove_hw_breakpoint = aarch64_linux_remove_hw_breakpoint;
  t->to_region_ok_for_hw_watchpoint =
    aarch64_linux_region_ok_for_hw_watchpoint;
  t->to_insert_watchpoint = aarch64_linux_insert_watchpoint;
  t->to_remove_watchpoint = aarch64_linux_remove_watchpoint;
  t->to_stopped_by_watchpoint = aarch64_linux_stopped_by_watchpoint;
  t->to_stopped_data_address = aarch64_linux_stopped_data_address;
  t->to_watchpoint_addr_within_range =
    aarch64_linux_watchpoint_addr_within_range;
  t->to_can_do_single_step = aarch64_linux_can_do_single_step;

  /* Override the GNU/Linux inferior startup hook.  */
  super_post_startup_inferior = t->to_post_startup_inferior;
  t->to_post_startup_inferior = aarch64_linux_child_post_startup_inferior;

  /* Register the target.  */
  linux_nat_add_target (t);
  linux_nat_set_new_thread (t, aarch64_linux_new_thread);
  linux_nat_set_new_fork (t, aarch64_linux_new_fork);
  linux_nat_set_forget_process (t, aarch64_forget_process);
  linux_nat_set_prepare_to_resume (t, aarch64_linux_prepare_to_resume);

  /* Add our siginfo layout converter.  */
  linux_nat_set_siginfo_fixup (t, aarch64_linux_siginfo_fixup);
}