aboutsummaryrefslogtreecommitdiff
path: root/gdb/arm-linux-tdep.c
blob: f58da846e65250599e428e977102e4802cd9d0ec (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
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
/* GNU/Linux on ARM target support.

   Copyright (C) 1999-2015 Free Software Foundation, Inc.

   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 "target.h"
#include "value.h"
#include "gdbtypes.h"
#include "floatformat.h"
#include "gdbcore.h"
#include "frame.h"
#include "regcache.h"
#include "doublest.h"
#include "solib-svr4.h"
#include "osabi.h"
#include "regset.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "breakpoint.h"
#include "auxv.h"
#include "xml-syscall.h"

#include "arm-tdep.h"
#include "arm-linux-tdep.h"
#include "linux-tdep.h"
#include "glibc-tdep.h"
#include "arch-utils.h"
#include "inferior.h"
#include "infrun.h"
#include "gdbthread.h"
#include "symfile.h"

#include "record-full.h"
#include "linux-record.h"

#include "cli/cli-utils.h"
#include "stap-probe.h"
#include "parser-defs.h"
#include "user-regs.h"
#include <ctype.h>
#include "elf/common.h"
extern int arm_apcs_32;

/* Under ARM GNU/Linux the traditional way of performing a breakpoint
   is to execute a particular software interrupt, rather than use a
   particular undefined instruction to provoke a trap.  Upon exection
   of the software interrupt the kernel stops the inferior with a
   SIGTRAP, and wakes the debugger.  */

static const gdb_byte arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef };

static const gdb_byte arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 };

/* However, the EABI syscall interface (new in Nov. 2005) does not look at
   the operand of the swi if old-ABI compatibility is disabled.  Therefore,
   use an undefined instruction instead.  This is supported as of kernel
   version 2.5.70 (May 2003), so should be a safe assumption for EABI
   binaries.  */

static const gdb_byte eabi_linux_arm_le_breakpoint[] = { 0xf0, 0x01, 0xf0, 0xe7 };

static const gdb_byte eabi_linux_arm_be_breakpoint[] = { 0xe7, 0xf0, 0x01, 0xf0 };

/* All the kernels which support Thumb support using a specific undefined
   instruction for the Thumb breakpoint.  */

static const gdb_byte arm_linux_thumb_be_breakpoint[] = {0xde, 0x01};

static const gdb_byte arm_linux_thumb_le_breakpoint[] = {0x01, 0xde};

/* Because the 16-bit Thumb breakpoint is affected by Thumb-2 IT blocks,
   we must use a length-appropriate breakpoint for 32-bit Thumb
   instructions.  See also thumb_get_next_pc.  */

static const gdb_byte arm_linux_thumb2_be_breakpoint[] = { 0xf7, 0xf0, 0xa0, 0x00 };

static const gdb_byte arm_linux_thumb2_le_breakpoint[] = { 0xf0, 0xf7, 0x00, 0xa0 };

/* Description of the longjmp buffer.  The buffer is treated as an array of 
   elements of size ARM_LINUX_JB_ELEMENT_SIZE.

   The location of saved registers in this buffer (in particular the PC
   to use after longjmp is called) varies depending on the ABI (in 
   particular the FP model) and also (possibly) the C Library.

   For glibc, eglibc, and uclibc the following holds:  If the FP model is 
   SoftVFP or VFP (which implies EABI) then the PC is at offset 9 in the 
   buffer.  This is also true for the SoftFPA model.  However, for the FPA 
   model the PC is at offset 21 in the buffer.  */
#define ARM_LINUX_JB_ELEMENT_SIZE	INT_REGISTER_SIZE
#define ARM_LINUX_JB_PC_FPA		21
#define ARM_LINUX_JB_PC_EABI		9

/*
   Dynamic Linking on ARM GNU/Linux
   --------------------------------

   Note: PLT = procedure linkage table
   GOT = global offset table

   As much as possible, ELF dynamic linking defers the resolution of
   jump/call addresses until the last minute.  The technique used is
   inspired by the i386 ELF design, and is based on the following
   constraints.

   1) The calling technique should not force a change in the assembly
   code produced for apps; it MAY cause changes in the way assembly
   code is produced for position independent code (i.e. shared
   libraries).

   2) The technique must be such that all executable areas must not be
   modified; and any modified areas must not be executed.

   To do this, there are three steps involved in a typical jump:

   1) in the code
   2) through the PLT
   3) using a pointer from the GOT

   When the executable or library is first loaded, each GOT entry is
   initialized to point to the code which implements dynamic name
   resolution and code finding.  This is normally a function in the
   program interpreter (on ARM GNU/Linux this is usually
   ld-linux.so.2, but it does not have to be).  On the first
   invocation, the function is located and the GOT entry is replaced
   with the real function address.  Subsequent calls go through steps
   1, 2 and 3 and end up calling the real code.

   1) In the code: 

   b    function_call
   bl   function_call

   This is typical ARM code using the 26 bit relative branch or branch
   and link instructions.  The target of the instruction
   (function_call is usually the address of the function to be called.
   In position independent code, the target of the instruction is
   actually an entry in the PLT when calling functions in a shared
   library.  Note that this call is identical to a normal function
   call, only the target differs.

   2) In the PLT:

   The PLT is a synthetic area, created by the linker.  It exists in
   both executables and libraries.  It is an array of stubs, one per
   imported function call.  It looks like this:

   PLT[0]:
   str     lr, [sp, #-4]!       @push the return address (lr)
   ldr     lr, [pc, #16]   @load from 6 words ahead
   add     lr, pc, lr      @form an address for GOT[0]
   ldr     pc, [lr, #8]!   @jump to the contents of that addr

   The return address (lr) is pushed on the stack and used for
   calculations.  The load on the second line loads the lr with
   &GOT[3] - . - 20.  The addition on the third leaves:

   lr = (&GOT[3] - . - 20) + (. + 8)
   lr = (&GOT[3] - 12)
   lr = &GOT[0]

   On the fourth line, the pc and lr are both updated, so that:

   pc = GOT[2]
   lr = &GOT[0] + 8
   = &GOT[2]

   NOTE: PLT[0] borrows an offset .word from PLT[1].  This is a little
   "tight", but allows us to keep all the PLT entries the same size.

   PLT[n+1]:
   ldr     ip, [pc, #4]    @load offset from gotoff
   add     ip, pc, ip      @add the offset to the pc
   ldr     pc, [ip]        @jump to that address
   gotoff: .word   GOT[n+3] - .

   The load on the first line, gets an offset from the fourth word of
   the PLT entry.  The add on the second line makes ip = &GOT[n+3],
   which contains either a pointer to PLT[0] (the fixup trampoline) or
   a pointer to the actual code.

   3) In the GOT:

   The GOT contains helper pointers for both code (PLT) fixups and
   data fixups.  The first 3 entries of the GOT are special.  The next
   M entries (where M is the number of entries in the PLT) belong to
   the PLT fixups.  The next D (all remaining) entries belong to
   various data fixups.  The actual size of the GOT is 3 + M + D.

   The GOT is also a synthetic area, created by the linker.  It exists
   in both executables and libraries.  When the GOT is first
   initialized , all the GOT entries relating to PLT fixups are
   pointing to code back at PLT[0].

   The special entries in the GOT are:

   GOT[0] = linked list pointer used by the dynamic loader
   GOT[1] = pointer to the reloc table for this module
   GOT[2] = pointer to the fixup/resolver code

   The first invocation of function call comes through and uses the
   fixup/resolver code.  On the entry to the fixup/resolver code:

   ip = &GOT[n+3]
   lr = &GOT[2]
   stack[0] = return address (lr) of the function call
   [r0, r1, r2, r3] are still the arguments to the function call

   This is enough information for the fixup/resolver code to work
   with.  Before the fixup/resolver code returns, it actually calls
   the requested function and repairs &GOT[n+3].  */

/* The constants below were determined by examining the following files
   in the linux kernel sources:

      arch/arm/kernel/signal.c
	  - see SWI_SYS_SIGRETURN and SWI_SYS_RT_SIGRETURN
      include/asm-arm/unistd.h
	  - see __NR_sigreturn, __NR_rt_sigreturn, and __NR_SYSCALL_BASE */

#define ARM_LINUX_SIGRETURN_INSTR	0xef900077
#define ARM_LINUX_RT_SIGRETURN_INSTR	0xef9000ad

/* For ARM EABI, the syscall number is not in the SWI instruction
   (instead it is loaded into r7).  We recognize the pattern that
   glibc uses...  alternatively, we could arrange to do this by
   function name, but they are not always exported.  */
#define ARM_SET_R7_SIGRETURN		0xe3a07077
#define ARM_SET_R7_RT_SIGRETURN		0xe3a070ad
#define ARM_EABI_SYSCALL		0xef000000

/* Equivalent patterns for Thumb2.  */
#define THUMB2_SET_R7_SIGRETURN1	0xf04f
#define THUMB2_SET_R7_SIGRETURN2	0x0777
#define THUMB2_SET_R7_RT_SIGRETURN1	0xf04f
#define THUMB2_SET_R7_RT_SIGRETURN2	0x07ad
#define THUMB2_EABI_SYSCALL		0xdf00

/* OABI syscall restart trampoline, used for EABI executables too
   whenever OABI support has been enabled in the kernel.  */
#define ARM_OABI_SYSCALL_RESTART_SYSCALL 0xef900000
#define ARM_LDR_PC_SP_12		0xe49df00c
#define ARM_LDR_PC_SP_4			0xe49df004

static void
arm_linux_sigtramp_cache (struct frame_info *this_frame,
			  struct trad_frame_cache *this_cache,
			  CORE_ADDR func, int regs_offset)
{
  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
  CORE_ADDR base = sp + regs_offset;
  int i;

  for (i = 0; i < 16; i++)
    trad_frame_set_reg_addr (this_cache, i, base + i * 4);

  trad_frame_set_reg_addr (this_cache, ARM_PS_REGNUM, base + 16 * 4);

  /* The VFP or iWMMXt registers may be saved on the stack, but there's
     no reliable way to restore them (yet).  */

  /* Save a frame ID.  */
  trad_frame_set_id (this_cache, frame_id_build (sp, func));
}

/* There are a couple of different possible stack layouts that
   we need to support.

   Before version 2.6.18, the kernel used completely independent
   layouts for non-RT and RT signals.  For non-RT signals the stack
   began directly with a struct sigcontext.  For RT signals the stack
   began with two redundant pointers (to the siginfo and ucontext),
   and then the siginfo and ucontext.

   As of version 2.6.18, the non-RT signal frame layout starts with
   a ucontext and the RT signal frame starts with a siginfo and then
   a ucontext.  Also, the ucontext now has a designated save area
   for coprocessor registers.

   For RT signals, it's easy to tell the difference: we look for
   pinfo, the pointer to the siginfo.  If it has the expected
   value, we have an old layout.  If it doesn't, we have the new
   layout.

   For non-RT signals, it's a bit harder.  We need something in one
   layout or the other with a recognizable offset and value.  We can't
   use the return trampoline, because ARM usually uses SA_RESTORER,
   in which case the stack return trampoline is not filled in.
   We can't use the saved stack pointer, because sigaltstack might
   be in use.  So for now we guess the new layout...  */

/* There are three words (trap_no, error_code, oldmask) in
   struct sigcontext before r0.  */
#define ARM_SIGCONTEXT_R0 0xc

/* There are five words (uc_flags, uc_link, and three for uc_stack)
   in the ucontext_t before the sigcontext.  */
#define ARM_UCONTEXT_SIGCONTEXT 0x14

/* There are three elements in an rt_sigframe before the ucontext:
   pinfo, puc, and info.  The first two are pointers and the third
   is a struct siginfo, with size 128 bytes.  We could follow puc
   to the ucontext, but it's simpler to skip the whole thing.  */
#define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8
#define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88

#define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80

#define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a

static void
arm_linux_sigreturn_init (const struct tramp_frame *self,
			  struct frame_info *this_frame,
			  struct trad_frame_cache *this_cache,
			  CORE_ADDR func)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
  ULONGEST uc_flags = read_memory_unsigned_integer (sp, 4, byte_order);

  if (uc_flags == ARM_NEW_SIGFRAME_MAGIC)
    arm_linux_sigtramp_cache (this_frame, this_cache, func,
			      ARM_UCONTEXT_SIGCONTEXT
			      + ARM_SIGCONTEXT_R0);
  else
    arm_linux_sigtramp_cache (this_frame, this_cache, func,
			      ARM_SIGCONTEXT_R0);
}

static void
arm_linux_rt_sigreturn_init (const struct tramp_frame *self,
			  struct frame_info *this_frame,
			  struct trad_frame_cache *this_cache,
			  CORE_ADDR func)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
  ULONGEST pinfo = read_memory_unsigned_integer (sp, 4, byte_order);

  if (pinfo == sp + ARM_OLD_RT_SIGFRAME_SIGINFO)
    arm_linux_sigtramp_cache (this_frame, this_cache, func,
			      ARM_OLD_RT_SIGFRAME_UCONTEXT
			      + ARM_UCONTEXT_SIGCONTEXT
			      + ARM_SIGCONTEXT_R0);
  else
    arm_linux_sigtramp_cache (this_frame, this_cache, func,
			      ARM_NEW_RT_SIGFRAME_UCONTEXT
			      + ARM_UCONTEXT_SIGCONTEXT
			      + ARM_SIGCONTEXT_R0);
}

static void
arm_linux_restart_syscall_init (const struct tramp_frame *self,
				struct frame_info *this_frame,
				struct trad_frame_cache *this_cache,
				CORE_ADDR func)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  CORE_ADDR sp = get_frame_register_unsigned (this_frame, ARM_SP_REGNUM);
  CORE_ADDR pc = get_frame_memory_unsigned (this_frame, sp, 4);
  CORE_ADDR cpsr = get_frame_register_unsigned (this_frame, ARM_PS_REGNUM);
  ULONGEST t_bit = arm_psr_thumb_bit (gdbarch);
  int sp_offset;

  /* There are two variants of this trampoline; with older kernels, the
     stub is placed on the stack, while newer kernels use the stub from
     the vector page.  They are identical except that the older version
     increments SP by 12 (to skip stored PC and the stub itself), while
     the newer version increments SP only by 4 (just the stored PC).  */
  if (self->insn[1].bytes == ARM_LDR_PC_SP_4)
    sp_offset = 4;
  else
    sp_offset = 12;

  /* Update Thumb bit in CPSR.  */
  if (pc & 1)
    cpsr |= t_bit;
  else
    cpsr &= ~t_bit;

  /* Remove Thumb bit from PC.  */
  pc = gdbarch_addr_bits_remove (gdbarch, pc);

  /* Save previous register values.  */
  trad_frame_set_reg_value (this_cache, ARM_SP_REGNUM, sp + sp_offset);
  trad_frame_set_reg_value (this_cache, ARM_PC_REGNUM, pc);
  trad_frame_set_reg_value (this_cache, ARM_PS_REGNUM, cpsr);

  /* Save a frame ID.  */
  trad_frame_set_id (this_cache, frame_id_build (sp, func));
}

static struct tramp_frame arm_linux_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  4,
  {
    { ARM_LINUX_SIGRETURN_INSTR, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_sigreturn_init
};

static struct tramp_frame arm_linux_rt_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  4,
  {
    { ARM_LINUX_RT_SIGRETURN_INSTR, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_rt_sigreturn_init
};

static struct tramp_frame arm_eabi_linux_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  4,
  {
    { ARM_SET_R7_SIGRETURN, -1 },
    { ARM_EABI_SYSCALL, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_sigreturn_init
};

static struct tramp_frame arm_eabi_linux_rt_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  4,
  {
    { ARM_SET_R7_RT_SIGRETURN, -1 },
    { ARM_EABI_SYSCALL, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_rt_sigreturn_init
};

static struct tramp_frame thumb2_eabi_linux_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  2,
  {
    { THUMB2_SET_R7_SIGRETURN1, -1 },
    { THUMB2_SET_R7_SIGRETURN2, -1 },
    { THUMB2_EABI_SYSCALL, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_sigreturn_init
};

static struct tramp_frame thumb2_eabi_linux_rt_sigreturn_tramp_frame = {
  SIGTRAMP_FRAME,
  2,
  {
    { THUMB2_SET_R7_RT_SIGRETURN1, -1 },
    { THUMB2_SET_R7_RT_SIGRETURN2, -1 },
    { THUMB2_EABI_SYSCALL, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_rt_sigreturn_init
};

static struct tramp_frame arm_linux_restart_syscall_tramp_frame = {
  NORMAL_FRAME,
  4,
  {
    { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 },
    { ARM_LDR_PC_SP_12, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_restart_syscall_init
};

static struct tramp_frame arm_kernel_linux_restart_syscall_tramp_frame = {
  NORMAL_FRAME,
  4,
  {
    { ARM_OABI_SYSCALL_RESTART_SYSCALL, -1 },
    { ARM_LDR_PC_SP_4, -1 },
    { TRAMP_SENTINEL_INSN }
  },
  arm_linux_restart_syscall_init
};

/* Core file and register set support.  */

#define ARM_LINUX_SIZEOF_GREGSET (18 * INT_REGISTER_SIZE)

void
arm_linux_supply_gregset (const struct regset *regset,
			  struct regcache *regcache,
			  int regnum, const void *gregs_buf, size_t len)
{
  struct gdbarch *gdbarch = get_regcache_arch (regcache);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  const gdb_byte *gregs = gregs_buf;
  int regno;
  CORE_ADDR reg_pc;
  gdb_byte pc_buf[INT_REGISTER_SIZE];

  for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      regcache_raw_supply (regcache, regno,
			   gregs + INT_REGISTER_SIZE * regno);

  if (regnum == ARM_PS_REGNUM || regnum == -1)
    {
      if (arm_apcs_32)
	regcache_raw_supply (regcache, ARM_PS_REGNUM,
			     gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM);
      else
	regcache_raw_supply (regcache, ARM_PS_REGNUM,
			     gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM);
    }

  if (regnum == ARM_PC_REGNUM || regnum == -1)
    {
      reg_pc = extract_unsigned_integer (gregs
					 + INT_REGISTER_SIZE * ARM_PC_REGNUM,
					 INT_REGISTER_SIZE, byte_order);
      reg_pc = gdbarch_addr_bits_remove (gdbarch, reg_pc);
      store_unsigned_integer (pc_buf, INT_REGISTER_SIZE, byte_order, reg_pc);
      regcache_raw_supply (regcache, ARM_PC_REGNUM, pc_buf);
    }
}

void
arm_linux_collect_gregset (const struct regset *regset,
			   const struct regcache *regcache,
			   int regnum, void *gregs_buf, size_t len)
{
  gdb_byte *gregs = gregs_buf;
  int regno;

  for (regno = ARM_A1_REGNUM; regno < ARM_PC_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      regcache_raw_collect (regcache, regno,
			    gregs + INT_REGISTER_SIZE * regno);

  if (regnum == ARM_PS_REGNUM || regnum == -1)
    {
      if (arm_apcs_32)
	regcache_raw_collect (regcache, ARM_PS_REGNUM,
			      gregs + INT_REGISTER_SIZE * ARM_CPSR_GREGNUM);
      else
	regcache_raw_collect (regcache, ARM_PS_REGNUM,
			      gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM);
    }

  if (regnum == ARM_PC_REGNUM || regnum == -1)
    regcache_raw_collect (regcache, ARM_PC_REGNUM,
			  gregs + INT_REGISTER_SIZE * ARM_PC_REGNUM);
}

/* Support for register format used by the NWFPE FPA emulator.  */

#define typeNone		0x00
#define typeSingle		0x01
#define typeDouble		0x02
#define typeExtended		0x03

void
supply_nwfpe_register (struct regcache *regcache, int regno,
		       const gdb_byte *regs)
{
  const gdb_byte *reg_data;
  gdb_byte reg_tag;
  gdb_byte buf[FP_REGISTER_SIZE];

  reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE;
  reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET];
  memset (buf, 0, FP_REGISTER_SIZE);

  switch (reg_tag)
    {
    case typeSingle:
      memcpy (buf, reg_data, 4);
      break;
    case typeDouble:
      memcpy (buf, reg_data + 4, 4);
      memcpy (buf + 4, reg_data, 4);
      break;
    case typeExtended:
      /* We want sign and exponent, then least significant bits,
	 then most significant.  NWFPE does sign, most, least.  */
      memcpy (buf, reg_data, 4);
      memcpy (buf + 4, reg_data + 8, 4);
      memcpy (buf + 8, reg_data + 4, 4);
      break;
    default:
      break;
    }

  regcache_raw_supply (regcache, regno, buf);
}

void
collect_nwfpe_register (const struct regcache *regcache, int regno,
			gdb_byte *regs)
{
  gdb_byte *reg_data;
  gdb_byte reg_tag;
  gdb_byte buf[FP_REGISTER_SIZE];

  regcache_raw_collect (regcache, regno, buf);

  /* NOTE drow/2006-06-07: This code uses the tag already in the
     register buffer.  I've preserved that when moving the code
     from the native file to the target file.  But this doesn't
     always make sense.  */

  reg_data = regs + (regno - ARM_F0_REGNUM) * FP_REGISTER_SIZE;
  reg_tag = regs[(regno - ARM_F0_REGNUM) + NWFPE_TAGS_OFFSET];

  switch (reg_tag)
    {
    case typeSingle:
      memcpy (reg_data, buf, 4);
      break;
    case typeDouble:
      memcpy (reg_data, buf + 4, 4);
      memcpy (reg_data + 4, buf, 4);
      break;
    case typeExtended:
      memcpy (reg_data, buf, 4);
      memcpy (reg_data + 4, buf + 8, 4);
      memcpy (reg_data + 8, buf + 4, 4);
      break;
    default:
      break;
    }
}

void
arm_linux_supply_nwfpe (const struct regset *regset,
			struct regcache *regcache,
			int regnum, const void *regs_buf, size_t len)
{
  const gdb_byte *regs = regs_buf;
  int regno;

  if (regnum == ARM_FPS_REGNUM || regnum == -1)
    regcache_raw_supply (regcache, ARM_FPS_REGNUM,
			 regs + NWFPE_FPSR_OFFSET);

  for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      supply_nwfpe_register (regcache, regno, regs);
}

void
arm_linux_collect_nwfpe (const struct regset *regset,
			 const struct regcache *regcache,
			 int regnum, void *regs_buf, size_t len)
{
  gdb_byte *regs = regs_buf;
  int regno;

  for (regno = ARM_F0_REGNUM; regno <= ARM_F7_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      collect_nwfpe_register (regcache, regno, regs);

  if (regnum == ARM_FPS_REGNUM || regnum == -1)
    regcache_raw_collect (regcache, ARM_FPS_REGNUM,
			  regs + INT_REGISTER_SIZE * ARM_FPS_REGNUM);
}

/* Support VFP register format.  */

#define ARM_LINUX_SIZEOF_VFP (32 * 8 + 4)

static void
arm_linux_supply_vfp (const struct regset *regset,
		      struct regcache *regcache,
		      int regnum, const void *regs_buf, size_t len)
{
  const gdb_byte *regs = regs_buf;
  int regno;

  if (regnum == ARM_FPSCR_REGNUM || regnum == -1)
    regcache_raw_supply (regcache, ARM_FPSCR_REGNUM, regs + 32 * 8);

  for (regno = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      regcache_raw_supply (regcache, regno,
			   regs + (regno - ARM_D0_REGNUM) * 8);
}

static void
arm_linux_collect_vfp (const struct regset *regset,
			 const struct regcache *regcache,
			 int regnum, void *regs_buf, size_t len)
{
  gdb_byte *regs = regs_buf;
  int regno;

  if (regnum == ARM_FPSCR_REGNUM || regnum == -1)
    regcache_raw_collect (regcache, ARM_FPSCR_REGNUM, regs + 32 * 8);

  for (regno = ARM_D0_REGNUM; regno <= ARM_D31_REGNUM; regno++)
    if (regnum == -1 || regnum == regno)
      regcache_raw_collect (regcache, regno,
			    regs + (regno - ARM_D0_REGNUM) * 8);
}

static const struct regset arm_linux_gregset =
  {
    NULL, arm_linux_supply_gregset, arm_linux_collect_gregset
  };

static const struct regset arm_linux_fpregset =
  {
    NULL, arm_linux_supply_nwfpe, arm_linux_collect_nwfpe
  };

static const struct regset arm_linux_vfpregset =
  {
    NULL, arm_linux_supply_vfp, arm_linux_collect_vfp
  };

/* Iterate over core file register note sections.  */

static void
arm_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
					iterate_over_regset_sections_cb *cb,
					void *cb_data,
					const struct regcache *regcache)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  cb (".reg", ARM_LINUX_SIZEOF_GREGSET, &arm_linux_gregset, NULL, cb_data);

  if (tdep->have_vfp_registers)
    cb (".reg-arm-vfp", ARM_LINUX_SIZEOF_VFP, &arm_linux_vfpregset,
	"VFP floating-point", cb_data);
  else if (tdep->have_fpa_registers)
    cb (".reg2", ARM_LINUX_SIZEOF_NWFPE, &arm_linux_fpregset,
	"FPA floating-point", cb_data);
}

/* Determine target description from core file.  */

static const struct target_desc *
arm_linux_core_read_description (struct gdbarch *gdbarch,
                                 struct target_ops *target,
                                 bfd *abfd)
{
  CORE_ADDR arm_hwcap = 0;

  if (target_auxv_search (target, AT_HWCAP, &arm_hwcap) != 1)
    return NULL;

  if (arm_hwcap & HWCAP_VFP)
    {
      /* NEON implies VFPv3-D32 or no-VFP unit.  Say that we only support
         Neon with VFPv3-D32.  */
      if (arm_hwcap & HWCAP_NEON)
	return tdesc_arm_with_neon;
      else if ((arm_hwcap & (HWCAP_VFPv3 | HWCAP_VFPv3D16)) == HWCAP_VFPv3)
	return tdesc_arm_with_vfpv3;
      else
	return tdesc_arm_with_vfpv2;
    }

  return NULL;
}


/* Copy the value of next pc of sigreturn and rt_sigrturn into PC,
   return 1.  In addition, set IS_THUMB depending on whether we
   will return to ARM or Thumb code.  Return 0 if it is not a
   rt_sigreturn/sigreturn syscall.  */
static int
arm_linux_sigreturn_return_addr (struct frame_info *frame,
				 unsigned long svc_number,
				 CORE_ADDR *pc, int *is_thumb)
{
  /* Is this a sigreturn or rt_sigreturn syscall?  */
  if (svc_number == 119 || svc_number == 173)
    {
      if (get_frame_type (frame) == SIGTRAMP_FRAME)
	{
	  ULONGEST t_bit = arm_psr_thumb_bit (frame_unwind_arch (frame));
	  CORE_ADDR cpsr
	    = frame_unwind_register_unsigned (frame, ARM_PS_REGNUM);

	  *is_thumb = (cpsr & t_bit) != 0;
	  *pc = frame_unwind_caller_pc (frame);
	  return 1;
	}
    }
  return 0;
}

/* At a ptrace syscall-stop, return the syscall number.  This either
   comes from the SWI instruction (OABI) or from r7 (EABI).

   When the function fails, it should return -1.  */

static LONGEST
arm_linux_get_syscall_number (struct gdbarch *gdbarch,
			      ptid_t ptid)
{
  struct regcache *regs = get_thread_regcache (ptid);
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  ULONGEST pc;
  ULONGEST cpsr;
  ULONGEST t_bit = arm_psr_thumb_bit (gdbarch);
  int is_thumb;
  ULONGEST svc_number = -1;

  regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &pc);
  regcache_cooked_read_unsigned (regs, ARM_PS_REGNUM, &cpsr);
  is_thumb = (cpsr & t_bit) != 0;

  if (is_thumb)
    {
      regcache_cooked_read_unsigned (regs, 7, &svc_number);
    }
  else
    {
      enum bfd_endian byte_order_for_code = 
	gdbarch_byte_order_for_code (gdbarch);

      /* PC gets incremented before the syscall-stop, so read the
	 previous instruction.  */
      unsigned long this_instr = 
	read_memory_unsigned_integer (pc - 4, 4, byte_order_for_code);

      unsigned long svc_operand = (0x00ffffff & this_instr);

      if (svc_operand)
	{
          /* OABI */
	  svc_number = svc_operand - 0x900000;
	}
      else
	{
          /* EABI */
	  regcache_cooked_read_unsigned (regs, 7, &svc_number);
	}
    }

  return svc_number;
}

/* When FRAME is at a syscall instruction, return the PC of the next
   instruction to be executed.  */

static CORE_ADDR
arm_linux_syscall_next_pc (struct frame_info *frame)
{
  CORE_ADDR pc = get_frame_pc (frame);
  CORE_ADDR return_addr = 0;
  int is_thumb = arm_frame_is_thumb (frame);
  ULONGEST svc_number = 0;

  if (is_thumb)
    {
      svc_number = get_frame_register_unsigned (frame, 7);
      return_addr = pc + 2;
    }
  else
    {
      struct gdbarch *gdbarch = get_frame_arch (frame);
      enum bfd_endian byte_order_for_code = 
	gdbarch_byte_order_for_code (gdbarch);
      unsigned long this_instr = 
	read_memory_unsigned_integer (pc, 4, byte_order_for_code);

      unsigned long svc_operand = (0x00ffffff & this_instr);
      if (svc_operand)  /* OABI.  */
	{
	  svc_number = svc_operand - 0x900000;
	}
      else /* EABI.  */
	{
	  svc_number = get_frame_register_unsigned (frame, 7);
	}

      return_addr = pc + 4;
    }

  arm_linux_sigreturn_return_addr (frame, svc_number, &return_addr, &is_thumb);

  /* Addresses for calling Thumb functions have the bit 0 set.  */
  if (is_thumb)
    return_addr |= 1;

  return return_addr;
}


/* Insert a single step breakpoint at the next executed instruction.  */

static int
arm_linux_software_single_step (struct frame_info *frame)
{
  struct gdbarch *gdbarch = get_frame_arch (frame);
  struct address_space *aspace = get_frame_address_space (frame);
  CORE_ADDR next_pc;

  if (arm_deal_with_atomic_sequence (frame))
    return 1;

  next_pc = arm_get_next_pc (frame, get_frame_pc (frame));

  /* The Linux kernel offers some user-mode helpers in a high page.  We can
     not read this page (as of 2.6.23), and even if we could then we couldn't
     set breakpoints in it, and even if we could then the atomic operations
     would fail when interrupted.  They are all called as functions and return
     to the address in LR, so step to there instead.  */
  if (next_pc > 0xffff0000)
    next_pc = get_frame_register_unsigned (frame, ARM_LR_REGNUM);

  arm_insert_single_step_breakpoint (gdbarch, aspace, next_pc);

  return 1;
}

/* Support for displaced stepping of Linux SVC instructions.  */

static void
arm_linux_cleanup_svc (struct gdbarch *gdbarch,
		       struct regcache *regs,
		       struct displaced_step_closure *dsc)
{
  CORE_ADDR from = dsc->insn_addr;
  ULONGEST apparent_pc;
  int within_scratch;

  regcache_cooked_read_unsigned (regs, ARM_PC_REGNUM, &apparent_pc);

  within_scratch = (apparent_pc >= dsc->scratch_base
		    && apparent_pc < (dsc->scratch_base
				      + DISPLACED_MODIFIED_INSNS * 4 + 4));

  if (debug_displaced)
    {
      fprintf_unfiltered (gdb_stdlog, "displaced: PC is apparently %.8lx after "
			  "SVC step ", (unsigned long) apparent_pc);
      if (within_scratch)
        fprintf_unfiltered (gdb_stdlog, "(within scratch space)\n");
      else
        fprintf_unfiltered (gdb_stdlog, "(outside scratch space)\n");
    }

  if (within_scratch)
    displaced_write_reg (regs, dsc, ARM_PC_REGNUM, from + 4, BRANCH_WRITE_PC);
}

static int
arm_linux_copy_svc (struct gdbarch *gdbarch, struct regcache *regs,
		    struct displaced_step_closure *dsc)
{
  CORE_ADDR return_to = 0;

  struct frame_info *frame;
  unsigned int svc_number = displaced_read_reg (regs, dsc, 7);
  int is_sigreturn = 0;
  int is_thumb;

  frame = get_current_frame ();

  is_sigreturn = arm_linux_sigreturn_return_addr(frame, svc_number,
						 &return_to, &is_thumb);
  if (is_sigreturn)
    {
	  struct symtab_and_line sal;

	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: found "
	      "sigreturn/rt_sigreturn SVC call.  PC in frame = %lx\n",
	      (unsigned long) get_frame_pc (frame));

	  if (debug_displaced)
	    fprintf_unfiltered (gdb_stdlog, "displaced: unwind pc = %lx.  "
	      "Setting momentary breakpoint.\n", (unsigned long) return_to);

	  gdb_assert (inferior_thread ()->control.step_resume_breakpoint
		      == NULL);

	  sal = find_pc_line (return_to, 0);
	  sal.pc = return_to;
	  sal.section = find_pc_overlay (return_to);
	  sal.explicit_pc = 1;

	  frame = get_prev_frame (frame);

	  if (frame)
	    {
	      inferior_thread ()->control.step_resume_breakpoint
        	= set_momentary_breakpoint (gdbarch, sal, get_frame_id (frame),
					    bp_step_resume);

	      /* set_momentary_breakpoint invalidates FRAME.  */
	      frame = NULL;

	      /* We need to make sure we actually insert the momentary
	         breakpoint set above.  */
	      insert_breakpoints ();
	    }
	  else if (debug_displaced)
	    fprintf_unfiltered (gdb_stderr, "displaced: couldn't find previous "
				"frame to set momentary breakpoint for "
				"sigreturn/rt_sigreturn\n");
	}
      else if (debug_displaced)
	fprintf_unfiltered (gdb_stdlog, "displaced: sigreturn/rt_sigreturn "
			    "SVC call not in signal trampoline frame\n");
    

  /* Preparation: If we detect sigreturn, set momentary breakpoint at resume
		  location, else nothing.
     Insn: unmodified svc.
     Cleanup: if pc lands in scratch space, pc <- insn_addr + 4
              else leave pc alone.  */


  dsc->cleanup = &arm_linux_cleanup_svc;
  /* Pretend we wrote to the PC, so cleanup doesn't set PC to the next
     instruction.  */
  dsc->wrote_to_pc = 1;

  return 0;
}


/* The following two functions implement single-stepping over calls to Linux
   kernel helper routines, which perform e.g. atomic operations on architecture
   variants which don't support them natively.

   When this function is called, the PC will be pointing at the kernel helper
   (at an address inaccessible to GDB), and r14 will point to the return
   address.  Displaced stepping always executes code in the copy area:
   so, make the copy-area instruction branch back to the kernel helper (the
   "from" address), and make r14 point to the breakpoint in the copy area.  In
   that way, we regain control once the kernel helper returns, and can clean
   up appropriately (as if we had just returned from the kernel helper as it
   would have been called from the non-displaced location).  */

static void
cleanup_kernel_helper_return (struct gdbarch *gdbarch,
			      struct regcache *regs,
			      struct displaced_step_closure *dsc)
{
  displaced_write_reg (regs, dsc, ARM_LR_REGNUM, dsc->tmp[0], CANNOT_WRITE_PC);
  displaced_write_reg (regs, dsc, ARM_PC_REGNUM, dsc->tmp[0], BRANCH_WRITE_PC);
}

static void
arm_catch_kernel_helper_return (struct gdbarch *gdbarch, CORE_ADDR from,
				CORE_ADDR to, struct regcache *regs,
				struct displaced_step_closure *dsc)
{
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  dsc->numinsns = 1;
  dsc->insn_addr = from;
  dsc->cleanup = &cleanup_kernel_helper_return;
  /* Say we wrote to the PC, else cleanup will set PC to the next
     instruction in the helper, which isn't helpful.  */
  dsc->wrote_to_pc = 1;

  /* Preparation: tmp[0] <- r14
                  r14 <- <scratch space>+4
		  *(<scratch space>+8) <- from
     Insn: ldr pc, [r14, #4]
     Cleanup: r14 <- tmp[0], pc <- tmp[0].  */

  dsc->tmp[0] = displaced_read_reg (regs, dsc, ARM_LR_REGNUM);
  displaced_write_reg (regs, dsc, ARM_LR_REGNUM, (ULONGEST) to + 4,
		       CANNOT_WRITE_PC);
  write_memory_unsigned_integer (to + 8, 4, byte_order, from);

  dsc->modinsn[0] = 0xe59ef004;  /* ldr pc, [lr, #4].  */
}

/* Linux-specific displaced step instruction copying function.  Detects when
   the program has stepped into a Linux kernel helper routine (which must be
   handled as a special case), falling back to arm_displaced_step_copy_insn()
   if it hasn't.  */

static struct displaced_step_closure *
arm_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
				    CORE_ADDR from, CORE_ADDR to,
				    struct regcache *regs)
{
  struct displaced_step_closure *dsc
    = xmalloc (sizeof (struct displaced_step_closure));

  /* Detect when we enter an (inaccessible by GDB) Linux kernel helper, and
     stop at the return location.  */
  if (from > 0xffff0000)
    {
      if (debug_displaced)
        fprintf_unfiltered (gdb_stdlog, "displaced: detected kernel helper "
			    "at %.8lx\n", (unsigned long) from);

      arm_catch_kernel_helper_return (gdbarch, from, to, regs, dsc);
    }
  else
    {
      /* Override the default handling of SVC instructions.  */
      dsc->u.svc.copy_svc_os = arm_linux_copy_svc;

      arm_process_displaced_insn (gdbarch, from, to, regs, dsc);
    }

  arm_displaced_init_closure (gdbarch, from, to, dsc);

  return dsc;
}

/* Implementation of `gdbarch_stap_is_single_operand', as defined in
   gdbarch.h.  */

static int
arm_stap_is_single_operand (struct gdbarch *gdbarch, const char *s)
{
  return (*s == '#' || *s == '$' || isdigit (*s) /* Literal number.  */
	  || *s == '[' /* Register indirection or
			  displacement.  */
	  || isalpha (*s)); /* Register value.  */
}

/* This routine is used to parse a special token in ARM's assembly.

   The special tokens parsed by it are:

      - Register displacement (e.g, [fp, #-8])

   It returns one if the special token has been parsed successfully,
   or zero if the current token is not considered special.  */

static int
arm_stap_parse_special_token (struct gdbarch *gdbarch,
			      struct stap_parse_info *p)
{
  if (*p->arg == '[')
    {
      /* Temporary holder for lookahead.  */
      const char *tmp = p->arg;
      char *endp;
      /* Used to save the register name.  */
      const char *start;
      char *regname;
      int len, offset;
      int got_minus = 0;
      long displacement;
      struct stoken str;

      ++tmp;
      start = tmp;

      /* Register name.  */
      while (isalnum (*tmp))
	++tmp;

      if (*tmp != ',')
	return 0;

      len = tmp - start;
      regname = alloca (len + 2);

      offset = 0;
      if (isdigit (*start))
	{
	  /* If we are dealing with a register whose name begins with a
	     digit, it means we should prefix the name with the letter
	     `r', because GDB expects this name pattern.  Otherwise (e.g.,
	     we are dealing with the register `fp'), we don't need to
	     add such a prefix.  */
	  regname[0] = 'r';
	  offset = 1;
	}

      strncpy (regname + offset, start, len);
      len += offset;
      regname[len] = '\0';

      if (user_reg_map_name_to_regnum (gdbarch, regname, len) == -1)
	error (_("Invalid register name `%s' on expression `%s'."),
	       regname, p->saved_arg);

      ++tmp;
      tmp = skip_spaces_const (tmp);
      if (*tmp == '#' || *tmp == '$')
	++tmp;

      if (*tmp == '-')
	{
	  ++tmp;
	  got_minus = 1;
	}

      displacement = strtol (tmp, &endp, 10);
      tmp = endp;

      /* Skipping last `]'.  */
      if (*tmp++ != ']')
	return 0;

      /* The displacement.  */
      write_exp_elt_opcode (&p->pstate, OP_LONG);
      write_exp_elt_type (&p->pstate, builtin_type (gdbarch)->builtin_long);
      write_exp_elt_longcst (&p->pstate, displacement);
      write_exp_elt_opcode (&p->pstate, OP_LONG);
      if (got_minus)
	write_exp_elt_opcode (&p->pstate, UNOP_NEG);

      /* The register name.  */
      write_exp_elt_opcode (&p->pstate, OP_REGISTER);
      str.ptr = regname;
      str.length = len;
      write_exp_string (&p->pstate, str);
      write_exp_elt_opcode (&p->pstate, OP_REGISTER);

      write_exp_elt_opcode (&p->pstate, BINOP_ADD);

      /* Casting to the expected type.  */
      write_exp_elt_opcode (&p->pstate, UNOP_CAST);
      write_exp_elt_type (&p->pstate, lookup_pointer_type (p->arg_type));
      write_exp_elt_opcode (&p->pstate, UNOP_CAST);

      write_exp_elt_opcode (&p->pstate, UNOP_IND);

      p->arg = tmp;
    }
  else
    return 0;

  return 1;
}

/* ARM process record-replay constructs: syscall, signal etc.  */

struct linux_record_tdep arm_linux_record_tdep;

/* arm_canonicalize_syscall maps from the native arm Linux set
   of syscall ids into a canonical set of syscall ids used by
   process record.  */

static enum gdb_syscall
arm_canonicalize_syscall (int syscall)
{
  enum { sys_process_vm_writev = 377 };

  if (syscall <= gdb_sys_sched_getaffinity)
    return syscall;
  else if (syscall >= 243 && syscall <= 247)
    return syscall + 2;
  else if (syscall >= 248 && syscall <= 253)
    return syscall + 4;

  return -1;
}

/* Record all registers but PC register for process-record.  */

static int
arm_all_but_pc_registers_record (struct regcache *regcache)
{
  int i;

  for (i = 0; i < ARM_PC_REGNUM; i++)
    {
      if (record_full_arch_list_add_reg (regcache, ARM_A1_REGNUM + i))
        return -1;
    }

  if (record_full_arch_list_add_reg (regcache, ARM_PS_REGNUM))
    return -1;

  return 0;
}

/* Handler for arm system call instruction recording.  */

static int
arm_linux_syscall_record (struct regcache *regcache, unsigned long svc_number)
{
  int ret = 0;
  enum gdb_syscall syscall_gdb;

  syscall_gdb = arm_canonicalize_syscall (svc_number);

  if (syscall_gdb < 0)
    {
      printf_unfiltered (_("Process record and replay target doesn't "
                           "support syscall number %s\n"),
                           plongest (svc_number));
      return -1;
    }

  if (syscall_gdb == gdb_sys_sigreturn
      || syscall_gdb == gdb_sys_rt_sigreturn)
   {
     if (arm_all_but_pc_registers_record (regcache))
       return -1;
     return 0;
   }

  ret = record_linux_system_call (syscall_gdb, regcache,
                                  &arm_linux_record_tdep);
  if (ret != 0)
    return ret;

  /* Record the return value of the system call.  */
  if (record_full_arch_list_add_reg (regcache, ARM_A1_REGNUM))
    return -1;
  /* Record LR.  */
  if (record_full_arch_list_add_reg (regcache, ARM_LR_REGNUM))
    return -1;
  /* Record CPSR.  */
  if (record_full_arch_list_add_reg (regcache, ARM_PS_REGNUM))
    return -1;

  return 0;
}

/* Implement the skip_trampoline_code gdbarch method.  */

static CORE_ADDR
arm_linux_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
{
  CORE_ADDR target_pc = arm_skip_stub (frame, pc);

  if (target_pc != 0)
    return target_pc;

  return find_solib_trampoline_target (frame, pc);
}

static void
arm_linux_init_abi (struct gdbarch_info info,
		    struct gdbarch *gdbarch)
{
  static const char *const stap_integer_prefixes[] = { "#", "$", "", NULL };
  static const char *const stap_register_prefixes[] = { "r", NULL };
  static const char *const stap_register_indirection_prefixes[] = { "[",
								    NULL };
  static const char *const stap_register_indirection_suffixes[] = { "]",
								    NULL };
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  linux_init_abi (info, gdbarch);

  tdep->lowest_pc = 0x8000;
  if (info.byte_order_for_code == BFD_ENDIAN_BIG)
    {
      if (tdep->arm_abi == ARM_ABI_AAPCS)
	tdep->arm_breakpoint = eabi_linux_arm_be_breakpoint;
      else
	tdep->arm_breakpoint = arm_linux_arm_be_breakpoint;
      tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint;
      tdep->thumb2_breakpoint = arm_linux_thumb2_be_breakpoint;
    }
  else
    {
      if (tdep->arm_abi == ARM_ABI_AAPCS)
	tdep->arm_breakpoint = eabi_linux_arm_le_breakpoint;
      else
	tdep->arm_breakpoint = arm_linux_arm_le_breakpoint;
      tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint;
      tdep->thumb2_breakpoint = arm_linux_thumb2_le_breakpoint;
    }
  tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint);
  tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint);
  tdep->thumb2_breakpoint_size = sizeof (arm_linux_thumb2_le_breakpoint);

  if (tdep->fp_model == ARM_FLOAT_AUTO)
    tdep->fp_model = ARM_FLOAT_FPA;

  switch (tdep->fp_model)
    {
    case ARM_FLOAT_FPA:
      tdep->jb_pc = ARM_LINUX_JB_PC_FPA;
      break;
    case ARM_FLOAT_SOFT_FPA:
    case ARM_FLOAT_SOFT_VFP:
    case ARM_FLOAT_VFP:
      tdep->jb_pc = ARM_LINUX_JB_PC_EABI;
      break;
    default:
      internal_error
	(__FILE__, __LINE__,
         _("arm_linux_init_abi: Floating point model not supported"));
      break;
    }
  tdep->jb_elt_size = ARM_LINUX_JB_ELEMENT_SIZE;

  set_solib_svr4_fetch_link_map_offsets
    (gdbarch, svr4_ilp32_fetch_link_map_offsets);

  /* Single stepping.  */
  set_gdbarch_software_single_step (gdbarch, arm_linux_software_single_step);

  /* Shared library handling.  */
  set_gdbarch_skip_trampoline_code (gdbarch, arm_linux_skip_trampoline_code);
  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);

  /* Enable TLS support.  */
  set_gdbarch_fetch_tls_load_module_address (gdbarch,
                                             svr4_fetch_objfile_link_map);

  tramp_frame_prepend_unwinder (gdbarch,
				&arm_linux_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&arm_linux_rt_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&arm_eabi_linux_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&arm_eabi_linux_rt_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&thumb2_eabi_linux_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&thumb2_eabi_linux_rt_sigreturn_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&arm_linux_restart_syscall_tramp_frame);
  tramp_frame_prepend_unwinder (gdbarch,
				&arm_kernel_linux_restart_syscall_tramp_frame);

  /* Core file support.  */
  set_gdbarch_iterate_over_regset_sections
    (gdbarch, arm_linux_iterate_over_regset_sections);
  set_gdbarch_core_read_description (gdbarch, arm_linux_core_read_description);

  set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type);

  /* Displaced stepping.  */
  set_gdbarch_displaced_step_copy_insn (gdbarch,
					arm_linux_displaced_step_copy_insn);
  set_gdbarch_displaced_step_fixup (gdbarch, arm_displaced_step_fixup);
  set_gdbarch_displaced_step_free_closure (gdbarch,
					   simple_displaced_step_free_closure);
  set_gdbarch_displaced_step_location (gdbarch, linux_displaced_step_location);

  /* Reversible debugging, process record.  */
  set_gdbarch_process_record (gdbarch, arm_process_record);

  /* SystemTap functions.  */
  set_gdbarch_stap_integer_prefixes (gdbarch, stap_integer_prefixes);
  set_gdbarch_stap_register_prefixes (gdbarch, stap_register_prefixes);
  set_gdbarch_stap_register_indirection_prefixes (gdbarch,
					  stap_register_indirection_prefixes);
  set_gdbarch_stap_register_indirection_suffixes (gdbarch,
					  stap_register_indirection_suffixes);
  set_gdbarch_stap_gdb_register_prefix (gdbarch, "r");
  set_gdbarch_stap_is_single_operand (gdbarch, arm_stap_is_single_operand);
  set_gdbarch_stap_parse_special_token (gdbarch,
					arm_stap_parse_special_token);

  tdep->syscall_next_pc = arm_linux_syscall_next_pc;

  /* `catch syscall' */
  set_xml_syscall_file_name (gdbarch, "syscalls/arm-linux.xml");
  set_gdbarch_get_syscall_number (gdbarch, arm_linux_get_syscall_number);

  /* Syscall record.  */
  tdep->arm_syscall_record = arm_linux_syscall_record;

  /* Initialize the arm_linux_record_tdep.  */
  /* These values are the size of the type that will be used in a system
     call.  They are obtained from Linux Kernel source.  */
  arm_linux_record_tdep.size_pointer
    = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
  arm_linux_record_tdep.size__old_kernel_stat = 32;
  arm_linux_record_tdep.size_tms = 16;
  arm_linux_record_tdep.size_loff_t = 8;
  arm_linux_record_tdep.size_flock = 16;
  arm_linux_record_tdep.size_oldold_utsname = 45;
  arm_linux_record_tdep.size_ustat = 20;
  arm_linux_record_tdep.size_old_sigaction = 140;
  arm_linux_record_tdep.size_old_sigset_t = 128;
  arm_linux_record_tdep.size_rlimit = 8;
  arm_linux_record_tdep.size_rusage = 72;
  arm_linux_record_tdep.size_timeval = 8;
  arm_linux_record_tdep.size_timezone = 8;
  arm_linux_record_tdep.size_old_gid_t = 2;
  arm_linux_record_tdep.size_old_uid_t = 2;
  arm_linux_record_tdep.size_fd_set = 128;
  arm_linux_record_tdep.size_dirent = 268;
  arm_linux_record_tdep.size_dirent64 = 276;
  arm_linux_record_tdep.size_statfs = 64;
  arm_linux_record_tdep.size_statfs64 = 84;
  arm_linux_record_tdep.size_sockaddr = 16;
  arm_linux_record_tdep.size_int
    = gdbarch_int_bit (gdbarch) / TARGET_CHAR_BIT;
  arm_linux_record_tdep.size_long
    = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
  arm_linux_record_tdep.size_ulong
    = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
  arm_linux_record_tdep.size_msghdr = 28;
  arm_linux_record_tdep.size_itimerval = 16;
  arm_linux_record_tdep.size_stat = 88;
  arm_linux_record_tdep.size_old_utsname = 325;
  arm_linux_record_tdep.size_sysinfo = 64;
  arm_linux_record_tdep.size_msqid_ds = 88;
  arm_linux_record_tdep.size_shmid_ds = 84;
  arm_linux_record_tdep.size_new_utsname = 390;
  arm_linux_record_tdep.size_timex = 128;
  arm_linux_record_tdep.size_mem_dqinfo = 24;
  arm_linux_record_tdep.size_if_dqblk = 68;
  arm_linux_record_tdep.size_fs_quota_stat = 68;
  arm_linux_record_tdep.size_timespec = 8;
  arm_linux_record_tdep.size_pollfd = 8;
  arm_linux_record_tdep.size_NFS_FHSIZE = 32;
  arm_linux_record_tdep.size_knfsd_fh = 132;
  arm_linux_record_tdep.size_TASK_COMM_LEN = 16;
  arm_linux_record_tdep.size_sigaction = 140;
  arm_linux_record_tdep.size_sigset_t = 8;
  arm_linux_record_tdep.size_siginfo_t = 128;
  arm_linux_record_tdep.size_cap_user_data_t = 12;
  arm_linux_record_tdep.size_stack_t = 12;
  arm_linux_record_tdep.size_off_t = arm_linux_record_tdep.size_long;
  arm_linux_record_tdep.size_stat64 = 96;
  arm_linux_record_tdep.size_gid_t = 2;
  arm_linux_record_tdep.size_uid_t = 2;
  arm_linux_record_tdep.size_PAGE_SIZE = 4096;
  arm_linux_record_tdep.size_flock64 = 24;
  arm_linux_record_tdep.size_user_desc = 16;
  arm_linux_record_tdep.size_io_event = 32;
  arm_linux_record_tdep.size_iocb = 64;
  arm_linux_record_tdep.size_epoll_event = 12;
  arm_linux_record_tdep.size_itimerspec
    = arm_linux_record_tdep.size_timespec * 2;
  arm_linux_record_tdep.size_mq_attr = 32;
  arm_linux_record_tdep.size_siginfo = 128;
  arm_linux_record_tdep.size_termios = 36;
  arm_linux_record_tdep.size_termios2 = 44;
  arm_linux_record_tdep.size_pid_t = 4;
  arm_linux_record_tdep.size_winsize = 8;
  arm_linux_record_tdep.size_serial_struct = 60;
  arm_linux_record_tdep.size_serial_icounter_struct = 80;
  arm_linux_record_tdep.size_hayes_esp_config = 12;
  arm_linux_record_tdep.size_size_t = 4;
  arm_linux_record_tdep.size_iovec = 8;

  /* These values are the second argument of system call "sys_ioctl".
     They are obtained from Linux Kernel source.  */
  arm_linux_record_tdep.ioctl_TCGETS = 0x5401;
  arm_linux_record_tdep.ioctl_TCSETS = 0x5402;
  arm_linux_record_tdep.ioctl_TCSETSW = 0x5403;
  arm_linux_record_tdep.ioctl_TCSETSF = 0x5404;
  arm_linux_record_tdep.ioctl_TCGETA = 0x5405;
  arm_linux_record_tdep.ioctl_TCSETA = 0x5406;
  arm_linux_record_tdep.ioctl_TCSETAW = 0x5407;
  arm_linux_record_tdep.ioctl_TCSETAF = 0x5408;
  arm_linux_record_tdep.ioctl_TCSBRK = 0x5409;
  arm_linux_record_tdep.ioctl_TCXONC = 0x540a;
  arm_linux_record_tdep.ioctl_TCFLSH = 0x540b;
  arm_linux_record_tdep.ioctl_TIOCEXCL = 0x540c;
  arm_linux_record_tdep.ioctl_TIOCNXCL = 0x540d;
  arm_linux_record_tdep.ioctl_TIOCSCTTY = 0x540e;
  arm_linux_record_tdep.ioctl_TIOCGPGRP = 0x540f;
  arm_linux_record_tdep.ioctl_TIOCSPGRP = 0x5410;
  arm_linux_record_tdep.ioctl_TIOCOUTQ = 0x5411;
  arm_linux_record_tdep.ioctl_TIOCSTI = 0x5412;
  arm_linux_record_tdep.ioctl_TIOCGWINSZ = 0x5413;
  arm_linux_record_tdep.ioctl_TIOCSWINSZ = 0x5414;
  arm_linux_record_tdep.ioctl_TIOCMGET = 0x5415;
  arm_linux_record_tdep.ioctl_TIOCMBIS = 0x5416;
  arm_linux_record_tdep.ioctl_TIOCMBIC = 0x5417;
  arm_linux_record_tdep.ioctl_TIOCMSET = 0x5418;
  arm_linux_record_tdep.ioctl_TIOCGSOFTCAR = 0x5419;
  arm_linux_record_tdep.ioctl_TIOCSSOFTCAR = 0x541a;
  arm_linux_record_tdep.ioctl_FIONREAD = 0x541b;
  arm_linux_record_tdep.ioctl_TIOCINQ = arm_linux_record_tdep.ioctl_FIONREAD;
  arm_linux_record_tdep.ioctl_TIOCLINUX = 0x541c;
  arm_linux_record_tdep.ioctl_TIOCCONS = 0x541d;
  arm_linux_record_tdep.ioctl_TIOCGSERIAL = 0x541e;
  arm_linux_record_tdep.ioctl_TIOCSSERIAL = 0x541f;
  arm_linux_record_tdep.ioctl_TIOCPKT = 0x5420;
  arm_linux_record_tdep.ioctl_FIONBIO = 0x5421;
  arm_linux_record_tdep.ioctl_TIOCNOTTY = 0x5422;
  arm_linux_record_tdep.ioctl_TIOCSETD = 0x5423;
  arm_linux_record_tdep.ioctl_TIOCGETD = 0x5424;
  arm_linux_record_tdep.ioctl_TCSBRKP = 0x5425;
  arm_linux_record_tdep.ioctl_TIOCTTYGSTRUCT = 0x5426;
  arm_linux_record_tdep.ioctl_TIOCSBRK = 0x5427;
  arm_linux_record_tdep.ioctl_TIOCCBRK = 0x5428;
  arm_linux_record_tdep.ioctl_TIOCGSID = 0x5429;
  arm_linux_record_tdep.ioctl_TCGETS2 = 0x802c542a;
  arm_linux_record_tdep.ioctl_TCSETS2 = 0x402c542b;
  arm_linux_record_tdep.ioctl_TCSETSW2 = 0x402c542c;
  arm_linux_record_tdep.ioctl_TCSETSF2 = 0x402c542d;
  arm_linux_record_tdep.ioctl_TIOCGPTN = 0x80045430;
  arm_linux_record_tdep.ioctl_TIOCSPTLCK = 0x40045431;
  arm_linux_record_tdep.ioctl_FIONCLEX = 0x5450;
  arm_linux_record_tdep.ioctl_FIOCLEX = 0x5451;
  arm_linux_record_tdep.ioctl_FIOASYNC = 0x5452;
  arm_linux_record_tdep.ioctl_TIOCSERCONFIG = 0x5453;
  arm_linux_record_tdep.ioctl_TIOCSERGWILD = 0x5454;
  arm_linux_record_tdep.ioctl_TIOCSERSWILD = 0x5455;
  arm_linux_record_tdep.ioctl_TIOCGLCKTRMIOS = 0x5456;
  arm_linux_record_tdep.ioctl_TIOCSLCKTRMIOS = 0x5457;
  arm_linux_record_tdep.ioctl_TIOCSERGSTRUCT = 0x5458;
  arm_linux_record_tdep.ioctl_TIOCSERGETLSR = 0x5459;
  arm_linux_record_tdep.ioctl_TIOCSERGETMULTI = 0x545a;
  arm_linux_record_tdep.ioctl_TIOCSERSETMULTI = 0x545b;
  arm_linux_record_tdep.ioctl_TIOCMIWAIT = 0x545c;
  arm_linux_record_tdep.ioctl_TIOCGICOUNT = 0x545d;
  arm_linux_record_tdep.ioctl_TIOCGHAYESESP = 0x545e;
  arm_linux_record_tdep.ioctl_TIOCSHAYESESP = 0x545f;
  arm_linux_record_tdep.ioctl_FIOQSIZE = 0x5460;

  /* These values are the second argument of system call "sys_fcntl"
     and "sys_fcntl64".  They are obtained from Linux Kernel source.  */
  arm_linux_record_tdep.fcntl_F_GETLK = 5;
  arm_linux_record_tdep.fcntl_F_GETLK64 = 12;
  arm_linux_record_tdep.fcntl_F_SETLK64 = 13;
  arm_linux_record_tdep.fcntl_F_SETLKW64 = 14;

  arm_linux_record_tdep.arg1 = ARM_A1_REGNUM + 1;
  arm_linux_record_tdep.arg2 = ARM_A1_REGNUM + 2;
  arm_linux_record_tdep.arg3 = ARM_A1_REGNUM + 3;
  arm_linux_record_tdep.arg4 = ARM_A1_REGNUM + 3;
}

/* Provide a prototype to silence -Wmissing-prototypes.  */
extern initialize_file_ftype _initialize_arm_linux_tdep;

void
_initialize_arm_linux_tdep (void)
{
  gdbarch_register_osabi (bfd_arch_arm, 0, GDB_OSABI_LINUX,
			  arm_linux_init_abi);
}