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
|
/* Target-dependent code for GNU/Linux i386.
Copyright (C) 2000-2017 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 "gdbcore.h"
#include "frame.h"
#include "value.h"
#include "regcache.h"
#include "regset.h"
#include "inferior.h"
#include "osabi.h"
#include "reggroups.h"
#include "dwarf2-frame.h"
#include "i386-tdep.h"
#include "i386-linux-tdep.h"
#include "linux-tdep.h"
#include "utils.h"
#include "glibc-tdep.h"
#include "solib-svr4.h"
#include "symtab.h"
#include "arch-utils.h"
#include "xml-syscall.h"
#include "i387-tdep.h"
#include "x86-xstate.h"
/* The syscall's XML filename for i386. */
#define XML_SYSCALL_FILENAME_I386 "syscalls/i386-linux.xml"
#include "record-full.h"
#include "linux-record.h"
#include "features/i386/i386-linux.c"
#include "features/i386/i386-mmx-linux.c"
#include "features/i386/i386-mpx-linux.c"
#include "features/i386/i386-avx-mpx-linux.c"
#include "features/i386/i386-avx-linux.c"
#include "features/i386/i386-avx-avx512-linux.c"
#include "features/i386/i386-avx-mpx-avx512-pku-linux.c"
/* Return non-zero, when the register is in the corresponding register
group. Put the LINUX_ORIG_EAX register in the system group. */
static int
i386_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
struct reggroup *group)
{
if (regnum == I386_LINUX_ORIG_EAX_REGNUM)
return (group == system_reggroup
|| group == save_reggroup
|| group == restore_reggroup);
return i386_register_reggroup_p (gdbarch, regnum, group);
}
/* Recognizing signal handler frames. */
/* GNU/Linux has two flavors of signals. Normal signal handlers, and
"realtime" (RT) signals. The RT signals can provide additional
information to the signal handler if the SA_SIGINFO flag is set
when establishing a signal handler using `sigaction'. It is not
unlikely that future versions of GNU/Linux will support SA_SIGINFO
for normal signals too. */
/* When the i386 Linux kernel calls a signal handler and the
SA_RESTORER flag isn't set, the return address points to a bit of
code on the stack. This function returns whether the PC appears to
be within this bit of code.
The instruction sequence for normal signals is
pop %eax
mov $0x77, %eax
int $0x80
or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80.
Checking for the code sequence should be somewhat reliable, because
the effect is to call the system call sigreturn. This is unlikely
to occur anywhere other than in a signal trampoline.
It kind of sucks that we have to read memory from the process in
order to identify a signal trampoline, but there doesn't seem to be
any other way. Therefore we only do the memory reads if no
function name could be identified, which should be the case since
the code is on the stack.
Detection of signal trampolines for handlers that set the
SA_RESTORER flag is in general not possible. Unfortunately this is
what the GNU C Library has been doing for quite some time now.
However, as of version 2.1.2, the GNU C Library uses signal
trampolines (named __restore and __restore_rt) that are identical
to the ones used by the kernel. Therefore, these trampolines are
supported too. */
#define LINUX_SIGTRAMP_INSN0 0x58 /* pop %eax */
#define LINUX_SIGTRAMP_OFFSET0 0
#define LINUX_SIGTRAMP_INSN1 0xb8 /* mov $NNNN, %eax */
#define LINUX_SIGTRAMP_OFFSET1 1
#define LINUX_SIGTRAMP_INSN2 0xcd /* int */
#define LINUX_SIGTRAMP_OFFSET2 6
static const gdb_byte linux_sigtramp_code[] =
{
LINUX_SIGTRAMP_INSN0, /* pop %eax */
LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77, %eax */
LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */
};
#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
/* If THIS_FRAME is a sigtramp routine, return the address of the
start of the routine. Otherwise, return 0. */
static CORE_ADDR
i386_linux_sigtramp_start (struct frame_info *this_frame)
{
CORE_ADDR pc = get_frame_pc (this_frame);
gdb_byte buf[LINUX_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
one of the three instructions. We optimize for finding the PC at
the start, as will be the case when the trampoline is not the
first frame on the stack. We assume that in the case where the
PC is not at the start of the instruction sequence, there will be
a few trailing readable bytes on the stack. */
if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN))
return 0;
if (buf[0] != LINUX_SIGTRAMP_INSN0)
{
int adjust;
switch (buf[0])
{
case LINUX_SIGTRAMP_INSN1:
adjust = LINUX_SIGTRAMP_OFFSET1;
break;
case LINUX_SIGTRAMP_INSN2:
adjust = LINUX_SIGTRAMP_OFFSET2;
break;
default:
return 0;
}
pc -= adjust;
if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN))
return 0;
}
if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0)
return 0;
return pc;
}
/* This function does the same for RT signals. Here the instruction
sequence is
mov $0xad, %eax
int $0x80
or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80.
The effect is to call the system call rt_sigreturn. */
#define LINUX_RT_SIGTRAMP_INSN0 0xb8 /* mov $NNNN, %eax */
#define LINUX_RT_SIGTRAMP_OFFSET0 0
#define LINUX_RT_SIGTRAMP_INSN1 0xcd /* int */
#define LINUX_RT_SIGTRAMP_OFFSET1 5
static const gdb_byte linux_rt_sigtramp_code[] =
{
LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad, %eax */
LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */
};
#define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code)
/* If THIS_FRAME is an RT sigtramp routine, return the address of the
start of the routine. Otherwise, return 0. */
static CORE_ADDR
i386_linux_rt_sigtramp_start (struct frame_info *this_frame)
{
CORE_ADDR pc = get_frame_pc (this_frame);
gdb_byte buf[LINUX_RT_SIGTRAMP_LEN];
/* We only recognize a signal trampoline if PC is at the start of
one of the two instructions. We optimize for finding the PC at
the start, as will be the case when the trampoline is not the
first frame on the stack. We assume that in the case where the
PC is not at the start of the instruction sequence, there will be
a few trailing readable bytes on the stack. */
if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN))
return 0;
if (buf[0] != LINUX_RT_SIGTRAMP_INSN0)
{
if (buf[0] != LINUX_RT_SIGTRAMP_INSN1)
return 0;
pc -= LINUX_RT_SIGTRAMP_OFFSET1;
if (!safe_frame_unwind_memory (this_frame, pc, buf,
LINUX_RT_SIGTRAMP_LEN))
return 0;
}
if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0)
return 0;
return pc;
}
/* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp
routine. */
static int
i386_linux_sigtramp_p (struct frame_info *this_frame)
{
CORE_ADDR pc = get_frame_pc (this_frame);
const char *name;
find_pc_partial_function (pc, &name, NULL, NULL);
/* If we have NAME, we can optimize the search. The trampolines are
named __restore and __restore_rt. However, they aren't dynamically
exported from the shared C library, so the trampoline may appear to
be part of the preceding function. This should always be sigaction,
__sigaction, or __libc_sigaction (all aliases to the same function). */
if (name == NULL || strstr (name, "sigaction") != NULL)
return (i386_linux_sigtramp_start (this_frame) != 0
|| i386_linux_rt_sigtramp_start (this_frame) != 0);
return (strcmp ("__restore", name) == 0
|| strcmp ("__restore_rt", name) == 0);
}
/* Return one if the PC of THIS_FRAME is in a signal trampoline which
may have DWARF-2 CFI. */
static int
i386_linux_dwarf_signal_frame_p (struct gdbarch *gdbarch,
struct frame_info *this_frame)
{
CORE_ADDR pc = get_frame_pc (this_frame);
const char *name;
find_pc_partial_function (pc, &name, NULL, NULL);
/* If a vsyscall DSO is in use, the signal trampolines may have these
names. */
if (name && (strcmp (name, "__kernel_sigreturn") == 0
|| strcmp (name, "__kernel_rt_sigreturn") == 0))
return 1;
return 0;
}
/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
#define I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 20
/* Assuming THIS_FRAME is a GNU/Linux sigtramp routine, return the
address of the associated sigcontext structure. */
static CORE_ADDR
i386_linux_sigcontext_addr (struct frame_info *this_frame)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR pc;
CORE_ADDR sp;
gdb_byte buf[4];
get_frame_register (this_frame, I386_ESP_REGNUM, buf);
sp = extract_unsigned_integer (buf, 4, byte_order);
pc = i386_linux_sigtramp_start (this_frame);
if (pc)
{
/* The sigcontext structure lives on the stack, right after
the signum argument. We determine the address of the
sigcontext structure by looking at the frame's stack
pointer. Keep in mind that the first instruction of the
sigtramp code is "pop %eax". If the PC is after this
instruction, adjust the returned value accordingly. */
if (pc == get_frame_pc (this_frame))
return sp + 4;
return sp;
}
pc = i386_linux_rt_sigtramp_start (this_frame);
if (pc)
{
CORE_ADDR ucontext_addr;
/* The sigcontext structure is part of the user context. A
pointer to the user context is passed as the third argument
to the signal handler. */
read_memory (sp + 8, buf, 4);
ucontext_addr = extract_unsigned_integer (buf, 4, byte_order);
return ucontext_addr + I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
}
error (_("Couldn't recognize signal trampoline."));
return 0;
}
/* Set the program counter for process PTID to PC. */
static void
i386_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
{
regcache_cooked_write_unsigned (regcache, I386_EIP_REGNUM, pc);
/* We must be careful with modifying the program counter. If we
just interrupted a system call, the kernel might try to restart
it when we resume the inferior. On restarting the system call,
the kernel will try backing up the program counter even though it
no longer points at the system call. This typically results in a
SIGSEGV or SIGILL. We can prevent this by writing `-1' in the
"orig_eax" pseudo-register.
Note that "orig_eax" is saved when setting up a dummy call frame.
This means that it is properly restored when that frame is
popped, and that the interrupted system call will be restarted
when we resume the inferior on return from a function call from
within GDB. In all other cases the system call will not be
restarted. */
regcache_cooked_write_unsigned (regcache, I386_LINUX_ORIG_EAX_REGNUM, -1);
}
/* Record all registers but IP register for process-record. */
static int
i386_all_but_ip_registers_record (struct regcache *regcache)
{
if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_ECX_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EDX_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EBX_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_ESP_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EBP_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_ESI_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EDI_REGNUM))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EFLAGS_REGNUM))
return -1;
return 0;
}
/* i386_canonicalize_syscall maps from the native i386 Linux set
of syscall ids into a canonical set of syscall ids used by
process record (a mostly trivial mapping, since the canonical
set was originally taken from the i386 set). */
static enum gdb_syscall
i386_canonicalize_syscall (int syscall)
{
enum { i386_syscall_max = 499 };
if (syscall <= i386_syscall_max)
return (enum gdb_syscall) syscall;
else
return gdb_sys_no_syscall;
}
/* Value of the sigcode in case of a boundary fault. */
#define SIG_CODE_BONDARY_FAULT 3
/* i386 GNU/Linux implementation of the handle_segmentation_fault
gdbarch hook. Displays information related to MPX bound
violations. */
void
i386_linux_handle_segmentation_fault (struct gdbarch *gdbarch,
struct ui_out *uiout)
{
/* -Wmaybe-uninitialized */
CORE_ADDR lower_bound = 0, upper_bound = 0, access = 0;
int is_upper;
long sig_code = 0;
if (!i386_mpx_enabled ())
return;
TRY
{
/* Sigcode evaluates if the actual segfault is a boundary violation. */
sig_code = parse_and_eval_long ("$_siginfo.si_code\n");
lower_bound
= parse_and_eval_long ("$_siginfo._sifields._sigfault._addr_bnd._lower");
upper_bound
= parse_and_eval_long ("$_siginfo._sifields._sigfault._addr_bnd._upper");
access
= parse_and_eval_long ("$_siginfo._sifields._sigfault.si_addr");
}
CATCH (exception, RETURN_MASK_ALL)
{
return;
}
END_CATCH
/* If this is not a boundary violation just return. */
if (sig_code != SIG_CODE_BONDARY_FAULT)
return;
is_upper = (access > upper_bound ? 1 : 0);
uiout->text ("\n");
if (is_upper)
uiout->field_string ("sigcode-meaning", _("Upper bound violation"));
else
uiout->field_string ("sigcode-meaning", _("Lower bound violation"));
uiout->text (_(" while accessing address "));
uiout->field_fmt ("bound-access", "%s", paddress (gdbarch, access));
uiout->text (_("\nBounds: [lower = "));
uiout->field_fmt ("lower-bound", "%s", paddress (gdbarch, lower_bound));
uiout->text (_(", upper = "));
uiout->field_fmt ("upper-bound", "%s", paddress (gdbarch, upper_bound));
uiout->text (_("]"));
}
/* Parse the arguments of current system call instruction and record
the values of the registers and memory that will be changed into
"record_arch_list". This instruction is "int 0x80" (Linux
Kernel2.4) or "sysenter" (Linux Kernel 2.6).
Return -1 if something wrong. */
static struct linux_record_tdep i386_linux_record_tdep;
static int
i386_linux_intx80_sysenter_syscall_record (struct regcache *regcache)
{
int ret;
LONGEST syscall_native;
enum gdb_syscall syscall_gdb;
regcache_raw_read_signed (regcache, I386_EAX_REGNUM, &syscall_native);
syscall_gdb = i386_canonicalize_syscall (syscall_native);
if (syscall_gdb < 0)
{
printf_unfiltered (_("Process record and replay target doesn't "
"support syscall number %s\n"),
plongest (syscall_native));
return -1;
}
if (syscall_gdb == gdb_sys_sigreturn
|| syscall_gdb == gdb_sys_rt_sigreturn)
{
if (i386_all_but_ip_registers_record (regcache))
return -1;
return 0;
}
ret = record_linux_system_call (syscall_gdb, regcache,
&i386_linux_record_tdep);
if (ret)
return ret;
/* Record the return value of the system call. */
if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM))
return -1;
return 0;
}
#define I386_LINUX_xstate 270
#define I386_LINUX_frame_size 732
static int
i386_linux_record_signal (struct gdbarch *gdbarch,
struct regcache *regcache,
enum gdb_signal signal)
{
ULONGEST esp;
if (i386_all_but_ip_registers_record (regcache))
return -1;
if (record_full_arch_list_add_reg (regcache, I386_EIP_REGNUM))
return -1;
/* Record the change in the stack. */
regcache_raw_read_unsigned (regcache, I386_ESP_REGNUM, &esp);
/* This is for xstate.
sp -= sizeof (struct _fpstate); */
esp -= I386_LINUX_xstate;
/* This is for frame_size.
sp -= sizeof (struct rt_sigframe); */
esp -= I386_LINUX_frame_size;
if (record_full_arch_list_add_mem (esp,
I386_LINUX_xstate + I386_LINUX_frame_size))
return -1;
if (record_full_arch_list_add_end ())
return -1;
return 0;
}
/* Core of the implementation for gdbarch get_syscall_number. Get pending
syscall number from REGCACHE. If there is no pending syscall -1 will be
returned. Pending syscall means ptrace has stepped into the syscall but
another ptrace call will step out. PC is right after the int $0x80
/ syscall / sysenter instruction in both cases, PC does not change during
the second ptrace step. */
static LONGEST
i386_linux_get_syscall_number_from_regcache (struct regcache *regcache)
{
struct gdbarch *gdbarch = get_regcache_arch (regcache);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
/* The content of a register. */
gdb_byte buf[4];
/* The result. */
LONGEST ret;
/* Getting the system call number from the register.
When dealing with x86 architecture, this information
is stored at %eax register. */
regcache_cooked_read (regcache, I386_LINUX_ORIG_EAX_REGNUM, buf);
ret = extract_signed_integer (buf, 4, byte_order);
return ret;
}
/* Wrapper for i386_linux_get_syscall_number_from_regcache to make it
compatible with gdbarch get_syscall_number method prototype. */
static LONGEST
i386_linux_get_syscall_number (struct gdbarch *gdbarch,
ptid_t ptid)
{
struct regcache *regcache = get_thread_regcache (ptid);
return i386_linux_get_syscall_number_from_regcache (regcache);
}
/* The register sets used in GNU/Linux ELF core-dumps are identical to
the register sets in `struct user' that are used for a.out
core-dumps. These are also used by ptrace(2). The corresponding
types are `elf_gregset_t' for the general-purpose registers (with
`elf_greg_t' the type of a single GP register) and `elf_fpregset_t'
for the floating-point registers.
Those types used to be available under the names `gregset_t' and
`fpregset_t' too, and GDB used those names in the past. But those
names are now used for the register sets used in the `mcontext_t'
type, which have a different size and layout. */
/* Mapping between the general-purpose registers in `struct user'
format and GDB's register cache layout. */
/* From <sys/reg.h>. */
int i386_linux_gregset_reg_offset[] =
{
6 * 4, /* %eax */
1 * 4, /* %ecx */
2 * 4, /* %edx */
0 * 4, /* %ebx */
15 * 4, /* %esp */
5 * 4, /* %ebp */
3 * 4, /* %esi */
4 * 4, /* %edi */
12 * 4, /* %eip */
14 * 4, /* %eflags */
13 * 4, /* %cs */
16 * 4, /* %ss */
7 * 4, /* %ds */
8 * 4, /* %es */
9 * 4, /* %fs */
10 * 4, /* %gs */
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, /* MPX registers BND0 ... BND3. */
-1, -1, /* MPX registers BNDCFGU, BNDSTATUS. */
-1, -1, -1, -1, -1, -1, -1, -1, /* k0 ... k7 (AVX512) */
-1, -1, -1, -1, -1, -1, -1, -1, /* zmm0 ... zmm7 (AVX512) */
-1, /* PKRU register */
11 * 4, /* "orig_eax" */
};
/* Mapping between the general-purpose registers in `struct
sigcontext' format and GDB's register cache layout. */
/* From <asm/sigcontext.h>. */
static int i386_linux_sc_reg_offset[] =
{
11 * 4, /* %eax */
10 * 4, /* %ecx */
9 * 4, /* %edx */
8 * 4, /* %ebx */
7 * 4, /* %esp */
6 * 4, /* %ebp */
5 * 4, /* %esi */
4 * 4, /* %edi */
14 * 4, /* %eip */
16 * 4, /* %eflags */
15 * 4, /* %cs */
18 * 4, /* %ss */
3 * 4, /* %ds */
2 * 4, /* %es */
1 * 4, /* %fs */
0 * 4 /* %gs */
};
/* Get XSAVE extended state xcr0 from core dump. */
uint64_t
i386_linux_core_read_xcr0 (bfd *abfd)
{
asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate");
uint64_t xcr0;
if (xstate)
{
size_t size = bfd_section_size (abfd, xstate);
/* Check extended state size. */
if (size < X86_XSTATE_AVX_SIZE)
xcr0 = X86_XSTATE_SSE_MASK;
else
{
char contents[8];
if (! bfd_get_section_contents (abfd, xstate, contents,
I386_LINUX_XSAVE_XCR0_OFFSET,
8))
{
warning (_("Couldn't read `xcr0' bytes from "
"`.reg-xstate' section in core file."));
return 0;
}
xcr0 = bfd_get_64 (abfd, contents);
}
}
else
xcr0 = 0;
return xcr0;
}
/* See i386-linux-tdep.h. */
const struct target_desc *
i386_linux_read_description (uint64_t xcr0)
{
switch ((xcr0 & X86_XSTATE_ALL_MASK))
{
case X86_XSTATE_AVX_MPX_AVX512_PKU_MASK:
return tdesc_i386_avx_mpx_avx512_pku_linux;
case X86_XSTATE_AVX_AVX512_MASK:
return tdesc_i386_avx_avx512_linux;
case X86_XSTATE_MPX_MASK:
return tdesc_i386_mpx_linux;
case X86_XSTATE_AVX_MPX_MASK:
return tdesc_i386_avx_mpx_linux;
case X86_XSTATE_AVX_MASK:
return tdesc_i386_avx_linux;
case X86_XSTATE_SSE_MASK:
return tdesc_i386_linux;
case X86_XSTATE_X87_MASK:
return tdesc_i386_mmx_linux;
default:
break;
}
return NULL;
}
/* Get Linux/x86 target description from core dump. */
static const struct target_desc *
i386_linux_core_read_description (struct gdbarch *gdbarch,
struct target_ops *target,
bfd *abfd)
{
/* Linux/i386. */
uint64_t xcr0 = i386_linux_core_read_xcr0 (abfd);
const struct target_desc *tdesc = i386_linux_read_description (xcr0);
if (tdesc != NULL)
return tdesc;
if (bfd_get_section_by_name (abfd, ".reg-xfp") != NULL)
return i386_linux_read_description (X86_XSTATE_SSE_MASK);
else
return i386_linux_read_description (X86_XSTATE_X87_MASK);
}
/* Similar to i386_supply_fpregset, but use XSAVE extended state. */
static void
i386_linux_supply_xstateregset (const struct regset *regset,
struct regcache *regcache, int regnum,
const void *xstateregs, size_t len)
{
i387_supply_xsave (regcache, regnum, xstateregs);
}
struct type *
x86_linux_get_siginfo_type (struct gdbarch *gdbarch)
{
return linux_get_siginfo_type_with_fields (gdbarch, LINUX_SIGINFO_FIELD_ADDR_BND);
}
/* Similar to i386_collect_fpregset, but use XSAVE extended state. */
static void
i386_linux_collect_xstateregset (const struct regset *regset,
const struct regcache *regcache,
int regnum, void *xstateregs, size_t len)
{
i387_collect_xsave (regcache, regnum, xstateregs, 1);
}
/* Register set definitions. */
static const struct regset i386_linux_xstateregset =
{
NULL,
i386_linux_supply_xstateregset,
i386_linux_collect_xstateregset
};
/* Iterate over core file register note sections. */
static void
i386_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", 68, &i386_gregset, NULL, cb_data);
if (tdep->xcr0 & X86_XSTATE_AVX)
cb (".reg-xstate", X86_XSTATE_SIZE (tdep->xcr0),
&i386_linux_xstateregset, "XSAVE extended state", cb_data);
else if (tdep->xcr0 & X86_XSTATE_SSE)
cb (".reg-xfp", 512, &i386_fpregset, "extended floating-point",
cb_data);
else
cb (".reg2", 108, &i386_fpregset, NULL, cb_data);
}
/* Linux kernel shows PC value after the 'int $0x80' instruction even if
inferior is still inside the syscall. On next PTRACE_SINGLESTEP it will
finish the syscall but PC will not change.
Some vDSOs contain 'int $0x80; ret' and during stepping out of the syscall
i386_displaced_step_fixup would keep PC at the displaced pad location.
As PC is pointing to the 'ret' instruction before the step
i386_displaced_step_fixup would expect inferior has just executed that 'ret'
and PC should not be adjusted. In reality it finished syscall instead and
PC should get relocated back to its vDSO address. Hide the 'ret'
instruction by 'nop' so that i386_displaced_step_fixup is not confused.
It is not fully correct as the bytes in struct displaced_step_closure will
not match the inferior code. But we would need some new flag in
displaced_step_closure otherwise to keep the state that syscall is finishing
for the later i386_displaced_step_fixup execution as the syscall execution
is already no longer detectable there. The new flag field would mean
i386-linux-tdep.c needs to wrap all the displacement methods of i386-tdep.c
which does not seem worth it. The same effect is achieved by patching that
'nop' instruction there instead. */
static struct displaced_step_closure *
i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
CORE_ADDR from, CORE_ADDR to,
struct regcache *regs)
{
struct displaced_step_closure *closure;
closure = i386_displaced_step_copy_insn (gdbarch, from, to, regs);
if (i386_linux_get_syscall_number_from_regcache (regs) != -1)
{
/* Since we use simple_displaced_step_copy_insn, our closure is a
copy of the instruction. */
gdb_byte *insn = (gdb_byte *) closure;
/* Fake nop. */
insn[0] = 0x90;
}
return closure;
}
static void
i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
const struct target_desc *tdesc = info.target_desc;
struct tdesc_arch_data *tdesc_data
= (struct tdesc_arch_data *) info.tdep_info;
const struct tdesc_feature *feature;
int valid_p;
gdb_assert (tdesc_data);
linux_init_abi (info, gdbarch);
/* GNU/Linux uses ELF. */
i386_elf_init_abi (info, gdbarch);
/* Reserve a number for orig_eax. */
set_gdbarch_num_regs (gdbarch, I386_LINUX_NUM_REGS);
if (! tdesc_has_registers (tdesc))
tdesc = i386_linux_read_description (X86_XSTATE_SSE_MASK);
tdep->tdesc = tdesc;
feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
if (feature == NULL)
return;
valid_p = tdesc_numbered_register (feature, tdesc_data,
I386_LINUX_ORIG_EAX_REGNUM,
"orig_eax");
if (!valid_p)
return;
/* Add the %orig_eax register used for syscall restarting. */
set_gdbarch_write_pc (gdbarch, i386_linux_write_pc);
tdep->register_reggroup_p = i386_linux_register_reggroup_p;
tdep->gregset_reg_offset = i386_linux_gregset_reg_offset;
tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset);
tdep->sizeof_gregset = 17 * 4;
tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */
tdep->sigtramp_p = i386_linux_sigtramp_p;
tdep->sigcontext_addr = i386_linux_sigcontext_addr;
tdep->sc_reg_offset = i386_linux_sc_reg_offset;
tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset);
tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET;
set_gdbarch_process_record (gdbarch, i386_process_record);
set_gdbarch_process_record_signal (gdbarch, i386_linux_record_signal);
/* Initialize the i386_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. */
i386_linux_record_tdep.size_pointer
= gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
i386_linux_record_tdep.size__old_kernel_stat = 32;
i386_linux_record_tdep.size_tms = 16;
i386_linux_record_tdep.size_loff_t = 8;
i386_linux_record_tdep.size_flock = 16;
i386_linux_record_tdep.size_oldold_utsname = 45;
i386_linux_record_tdep.size_ustat = 20;
i386_linux_record_tdep.size_old_sigaction = 16;
i386_linux_record_tdep.size_old_sigset_t = 4;
i386_linux_record_tdep.size_rlimit = 8;
i386_linux_record_tdep.size_rusage = 72;
i386_linux_record_tdep.size_timeval = 8;
i386_linux_record_tdep.size_timezone = 8;
i386_linux_record_tdep.size_old_gid_t = 2;
i386_linux_record_tdep.size_old_uid_t = 2;
i386_linux_record_tdep.size_fd_set = 128;
i386_linux_record_tdep.size_old_dirent = 268;
i386_linux_record_tdep.size_statfs = 64;
i386_linux_record_tdep.size_statfs64 = 84;
i386_linux_record_tdep.size_sockaddr = 16;
i386_linux_record_tdep.size_int
= gdbarch_int_bit (gdbarch) / TARGET_CHAR_BIT;
i386_linux_record_tdep.size_long
= gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
i386_linux_record_tdep.size_ulong
= gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
i386_linux_record_tdep.size_msghdr = 28;
i386_linux_record_tdep.size_itimerval = 16;
i386_linux_record_tdep.size_stat = 88;
i386_linux_record_tdep.size_old_utsname = 325;
i386_linux_record_tdep.size_sysinfo = 64;
i386_linux_record_tdep.size_msqid_ds = 88;
i386_linux_record_tdep.size_shmid_ds = 84;
i386_linux_record_tdep.size_new_utsname = 390;
i386_linux_record_tdep.size_timex = 128;
i386_linux_record_tdep.size_mem_dqinfo = 24;
i386_linux_record_tdep.size_if_dqblk = 68;
i386_linux_record_tdep.size_fs_quota_stat = 68;
i386_linux_record_tdep.size_timespec = 8;
i386_linux_record_tdep.size_pollfd = 8;
i386_linux_record_tdep.size_NFS_FHSIZE = 32;
i386_linux_record_tdep.size_knfsd_fh = 132;
i386_linux_record_tdep.size_TASK_COMM_LEN = 16;
i386_linux_record_tdep.size_sigaction = 20;
i386_linux_record_tdep.size_sigset_t = 8;
i386_linux_record_tdep.size_siginfo_t = 128;
i386_linux_record_tdep.size_cap_user_data_t = 12;
i386_linux_record_tdep.size_stack_t = 12;
i386_linux_record_tdep.size_off_t = i386_linux_record_tdep.size_long;
i386_linux_record_tdep.size_stat64 = 96;
i386_linux_record_tdep.size_gid_t = 4;
i386_linux_record_tdep.size_uid_t = 4;
i386_linux_record_tdep.size_PAGE_SIZE = 4096;
i386_linux_record_tdep.size_flock64 = 24;
i386_linux_record_tdep.size_user_desc = 16;
i386_linux_record_tdep.size_io_event = 32;
i386_linux_record_tdep.size_iocb = 64;
i386_linux_record_tdep.size_epoll_event = 12;
i386_linux_record_tdep.size_itimerspec
= i386_linux_record_tdep.size_timespec * 2;
i386_linux_record_tdep.size_mq_attr = 32;
i386_linux_record_tdep.size_termios = 36;
i386_linux_record_tdep.size_termios2 = 44;
i386_linux_record_tdep.size_pid_t = 4;
i386_linux_record_tdep.size_winsize = 8;
i386_linux_record_tdep.size_serial_struct = 60;
i386_linux_record_tdep.size_serial_icounter_struct = 80;
i386_linux_record_tdep.size_hayes_esp_config = 12;
i386_linux_record_tdep.size_size_t = 4;
i386_linux_record_tdep.size_iovec = 8;
i386_linux_record_tdep.size_time_t = 4;
/* These values are the second argument of system call "sys_ioctl".
They are obtained from Linux Kernel source. */
i386_linux_record_tdep.ioctl_TCGETS = 0x5401;
i386_linux_record_tdep.ioctl_TCSETS = 0x5402;
i386_linux_record_tdep.ioctl_TCSETSW = 0x5403;
i386_linux_record_tdep.ioctl_TCSETSF = 0x5404;
i386_linux_record_tdep.ioctl_TCGETA = 0x5405;
i386_linux_record_tdep.ioctl_TCSETA = 0x5406;
i386_linux_record_tdep.ioctl_TCSETAW = 0x5407;
i386_linux_record_tdep.ioctl_TCSETAF = 0x5408;
i386_linux_record_tdep.ioctl_TCSBRK = 0x5409;
i386_linux_record_tdep.ioctl_TCXONC = 0x540A;
i386_linux_record_tdep.ioctl_TCFLSH = 0x540B;
i386_linux_record_tdep.ioctl_TIOCEXCL = 0x540C;
i386_linux_record_tdep.ioctl_TIOCNXCL = 0x540D;
i386_linux_record_tdep.ioctl_TIOCSCTTY = 0x540E;
i386_linux_record_tdep.ioctl_TIOCGPGRP = 0x540F;
i386_linux_record_tdep.ioctl_TIOCSPGRP = 0x5410;
i386_linux_record_tdep.ioctl_TIOCOUTQ = 0x5411;
i386_linux_record_tdep.ioctl_TIOCSTI = 0x5412;
i386_linux_record_tdep.ioctl_TIOCGWINSZ = 0x5413;
i386_linux_record_tdep.ioctl_TIOCSWINSZ = 0x5414;
i386_linux_record_tdep.ioctl_TIOCMGET = 0x5415;
i386_linux_record_tdep.ioctl_TIOCMBIS = 0x5416;
i386_linux_record_tdep.ioctl_TIOCMBIC = 0x5417;
i386_linux_record_tdep.ioctl_TIOCMSET = 0x5418;
i386_linux_record_tdep.ioctl_TIOCGSOFTCAR = 0x5419;
i386_linux_record_tdep.ioctl_TIOCSSOFTCAR = 0x541A;
i386_linux_record_tdep.ioctl_FIONREAD = 0x541B;
i386_linux_record_tdep.ioctl_TIOCINQ = i386_linux_record_tdep.ioctl_FIONREAD;
i386_linux_record_tdep.ioctl_TIOCLINUX = 0x541C;
i386_linux_record_tdep.ioctl_TIOCCONS = 0x541D;
i386_linux_record_tdep.ioctl_TIOCGSERIAL = 0x541E;
i386_linux_record_tdep.ioctl_TIOCSSERIAL = 0x541F;
i386_linux_record_tdep.ioctl_TIOCPKT = 0x5420;
i386_linux_record_tdep.ioctl_FIONBIO = 0x5421;
i386_linux_record_tdep.ioctl_TIOCNOTTY = 0x5422;
i386_linux_record_tdep.ioctl_TIOCSETD = 0x5423;
i386_linux_record_tdep.ioctl_TIOCGETD = 0x5424;
i386_linux_record_tdep.ioctl_TCSBRKP = 0x5425;
i386_linux_record_tdep.ioctl_TIOCTTYGSTRUCT = 0x5426;
i386_linux_record_tdep.ioctl_TIOCSBRK = 0x5427;
i386_linux_record_tdep.ioctl_TIOCCBRK = 0x5428;
i386_linux_record_tdep.ioctl_TIOCGSID = 0x5429;
i386_linux_record_tdep.ioctl_TCGETS2 = 0x802c542a;
i386_linux_record_tdep.ioctl_TCSETS2 = 0x402c542b;
i386_linux_record_tdep.ioctl_TCSETSW2 = 0x402c542c;
i386_linux_record_tdep.ioctl_TCSETSF2 = 0x402c542d;
i386_linux_record_tdep.ioctl_TIOCGPTN = 0x80045430;
i386_linux_record_tdep.ioctl_TIOCSPTLCK = 0x40045431;
i386_linux_record_tdep.ioctl_FIONCLEX = 0x5450;
i386_linux_record_tdep.ioctl_FIOCLEX = 0x5451;
i386_linux_record_tdep.ioctl_FIOASYNC = 0x5452;
i386_linux_record_tdep.ioctl_TIOCSERCONFIG = 0x5453;
i386_linux_record_tdep.ioctl_TIOCSERGWILD = 0x5454;
i386_linux_record_tdep.ioctl_TIOCSERSWILD = 0x5455;
i386_linux_record_tdep.ioctl_TIOCGLCKTRMIOS = 0x5456;
i386_linux_record_tdep.ioctl_TIOCSLCKTRMIOS = 0x5457;
i386_linux_record_tdep.ioctl_TIOCSERGSTRUCT = 0x5458;
i386_linux_record_tdep.ioctl_TIOCSERGETLSR = 0x5459;
i386_linux_record_tdep.ioctl_TIOCSERGETMULTI = 0x545A;
i386_linux_record_tdep.ioctl_TIOCSERSETMULTI = 0x545B;
i386_linux_record_tdep.ioctl_TIOCMIWAIT = 0x545C;
i386_linux_record_tdep.ioctl_TIOCGICOUNT = 0x545D;
i386_linux_record_tdep.ioctl_TIOCGHAYESESP = 0x545E;
i386_linux_record_tdep.ioctl_TIOCSHAYESESP = 0x545F;
i386_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. */
i386_linux_record_tdep.fcntl_F_GETLK = 5;
i386_linux_record_tdep.fcntl_F_GETLK64 = 12;
i386_linux_record_tdep.fcntl_F_SETLK64 = 13;
i386_linux_record_tdep.fcntl_F_SETLKW64 = 14;
i386_linux_record_tdep.arg1 = I386_EBX_REGNUM;
i386_linux_record_tdep.arg2 = I386_ECX_REGNUM;
i386_linux_record_tdep.arg3 = I386_EDX_REGNUM;
i386_linux_record_tdep.arg4 = I386_ESI_REGNUM;
i386_linux_record_tdep.arg5 = I386_EDI_REGNUM;
i386_linux_record_tdep.arg6 = I386_EBP_REGNUM;
tdep->i386_intx80_record = i386_linux_intx80_sysenter_syscall_record;
tdep->i386_sysenter_record = i386_linux_intx80_sysenter_syscall_record;
tdep->i386_syscall_record = i386_linux_intx80_sysenter_syscall_record;
/* N_FUN symbols in shared libaries have 0 for their values and need
to be relocated. */
set_gdbarch_sofun_address_maybe_missing (gdbarch, 1);
/* GNU/Linux uses SVR4-style shared libraries. */
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
set_solib_svr4_fetch_link_map_offsets
(gdbarch, svr4_ilp32_fetch_link_map_offsets);
/* GNU/Linux uses the dynamic linker included in the GNU C Library. */
set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
dwarf2_frame_set_signal_frame_p (gdbarch, i386_linux_dwarf_signal_frame_p);
/* Enable TLS support. */
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
/* Core file support. */
set_gdbarch_iterate_over_regset_sections
(gdbarch, i386_linux_iterate_over_regset_sections);
set_gdbarch_core_read_description (gdbarch,
i386_linux_core_read_description);
/* Displaced stepping. */
set_gdbarch_displaced_step_copy_insn (gdbarch,
i386_linux_displaced_step_copy_insn);
set_gdbarch_displaced_step_fixup (gdbarch, i386_displaced_step_fixup);
set_gdbarch_displaced_step_location (gdbarch,
linux_displaced_step_location);
/* Functions for 'catch syscall'. */
set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_I386);
set_gdbarch_get_syscall_number (gdbarch,
i386_linux_get_syscall_number);
set_gdbarch_get_siginfo_type (gdbarch, x86_linux_get_siginfo_type);
set_gdbarch_handle_segmentation_fault (gdbarch,
i386_linux_handle_segmentation_fault);
}
/* Provide a prototype to silence -Wmissing-prototypes. */
extern void _initialize_i386_linux_tdep (void);
void
_initialize_i386_linux_tdep (void)
{
gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX,
i386_linux_init_abi);
/* Initialize the Linux target description. */
initialize_tdesc_i386_linux ();
initialize_tdesc_i386_mmx_linux ();
initialize_tdesc_i386_avx_linux ();
initialize_tdesc_i386_mpx_linux ();
initialize_tdesc_i386_avx_mpx_linux ();
initialize_tdesc_i386_avx_avx512_linux ();
initialize_tdesc_i386_avx_mpx_avx512_pku_linux ();
}
|