1 /* Target-dependent code for GNU/Linux i386.
3 Copyright (C) 2000-2019 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
28 #include "reggroups.h"
29 #include "dwarf2-frame.h"
30 #include "i386-tdep.h"
31 #include "i386-linux-tdep.h"
32 #include "linux-tdep.h"
34 #include "glibc-tdep.h"
35 #include "solib-svr4.h"
37 #include "arch-utils.h"
38 #include "xml-syscall.h"
40 #include "i387-tdep.h"
41 #include "common/x86-xstate.h"
43 /* The syscall's XML filename for i386. */
44 #define XML_SYSCALL_FILENAME_I386 "syscalls/i386-linux.xml"
46 #include "record-full.h"
47 #include "linux-record.h"
49 #include "arch/i386.h"
50 #include "target-descriptions.h"
52 /* Return non-zero, when the register is in the corresponding register
53 group. Put the LINUX_ORIG_EAX register in the system group. */
55 i386_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
56 struct reggroup *group)
58 if (regnum == I386_LINUX_ORIG_EAX_REGNUM)
59 return (group == system_reggroup
60 || group == save_reggroup
61 || group == restore_reggroup);
62 return i386_register_reggroup_p (gdbarch, regnum, group);
66 /* Recognizing signal handler frames. */
68 /* GNU/Linux has two flavors of signals. Normal signal handlers, and
69 "realtime" (RT) signals. The RT signals can provide additional
70 information to the signal handler if the SA_SIGINFO flag is set
71 when establishing a signal handler using `sigaction'. It is not
72 unlikely that future versions of GNU/Linux will support SA_SIGINFO
73 for normal signals too. */
75 /* When the i386 Linux kernel calls a signal handler and the
76 SA_RESTORER flag isn't set, the return address points to a bit of
77 code on the stack. This function returns whether the PC appears to
78 be within this bit of code.
80 The instruction sequence for normal signals is
84 or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80.
86 Checking for the code sequence should be somewhat reliable, because
87 the effect is to call the system call sigreturn. This is unlikely
88 to occur anywhere other than in a signal trampoline.
90 It kind of sucks that we have to read memory from the process in
91 order to identify a signal trampoline, but there doesn't seem to be
92 any other way. Therefore we only do the memory reads if no
93 function name could be identified, which should be the case since
94 the code is on the stack.
96 Detection of signal trampolines for handlers that set the
97 SA_RESTORER flag is in general not possible. Unfortunately this is
98 what the GNU C Library has been doing for quite some time now.
99 However, as of version 2.1.2, the GNU C Library uses signal
100 trampolines (named __restore and __restore_rt) that are identical
101 to the ones used by the kernel. Therefore, these trampolines are
104 #define LINUX_SIGTRAMP_INSN0 0x58 /* pop %eax */
105 #define LINUX_SIGTRAMP_OFFSET0 0
106 #define LINUX_SIGTRAMP_INSN1 0xb8 /* mov $NNNN, %eax */
107 #define LINUX_SIGTRAMP_OFFSET1 1
108 #define LINUX_SIGTRAMP_INSN2 0xcd /* int */
109 #define LINUX_SIGTRAMP_OFFSET2 6
111 static const gdb_byte linux_sigtramp_code[] =
113 LINUX_SIGTRAMP_INSN0, /* pop %eax */
114 LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77, %eax */
115 LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */
118 #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
120 /* If THIS_FRAME is a sigtramp routine, return the address of the
121 start of the routine. Otherwise, return 0. */
124 i386_linux_sigtramp_start (struct frame_info *this_frame)
126 CORE_ADDR pc = get_frame_pc (this_frame);
127 gdb_byte buf[LINUX_SIGTRAMP_LEN];
129 /* We only recognize a signal trampoline if PC is at the start of
130 one of the three instructions. We optimize for finding the PC at
131 the start, as will be the case when the trampoline is not the
132 first frame on the stack. We assume that in the case where the
133 PC is not at the start of the instruction sequence, there will be
134 a few trailing readable bytes on the stack. */
136 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN))
139 if (buf[0] != LINUX_SIGTRAMP_INSN0)
145 case LINUX_SIGTRAMP_INSN1:
146 adjust = LINUX_SIGTRAMP_OFFSET1;
148 case LINUX_SIGTRAMP_INSN2:
149 adjust = LINUX_SIGTRAMP_OFFSET2;
157 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN))
161 if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0)
167 /* This function does the same for RT signals. Here the instruction
171 or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80.
173 The effect is to call the system call rt_sigreturn. */
175 #define LINUX_RT_SIGTRAMP_INSN0 0xb8 /* mov $NNNN, %eax */
176 #define LINUX_RT_SIGTRAMP_OFFSET0 0
177 #define LINUX_RT_SIGTRAMP_INSN1 0xcd /* int */
178 #define LINUX_RT_SIGTRAMP_OFFSET1 5
180 static const gdb_byte linux_rt_sigtramp_code[] =
182 LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad, %eax */
183 LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */
186 #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code)
188 /* If THIS_FRAME is an RT sigtramp routine, return the address of the
189 start of the routine. Otherwise, return 0. */
192 i386_linux_rt_sigtramp_start (struct frame_info *this_frame)
194 CORE_ADDR pc = get_frame_pc (this_frame);
195 gdb_byte buf[LINUX_RT_SIGTRAMP_LEN];
197 /* We only recognize a signal trampoline if PC is at the start of
198 one of the two instructions. We optimize for finding the PC at
199 the start, as will be the case when the trampoline is not the
200 first frame on the stack. We assume that in the case where the
201 PC is not at the start of the instruction sequence, there will be
202 a few trailing readable bytes on the stack. */
204 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN))
207 if (buf[0] != LINUX_RT_SIGTRAMP_INSN0)
209 if (buf[0] != LINUX_RT_SIGTRAMP_INSN1)
212 pc -= LINUX_RT_SIGTRAMP_OFFSET1;
214 if (!safe_frame_unwind_memory (this_frame, pc, buf,
215 LINUX_RT_SIGTRAMP_LEN))
219 if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0)
225 /* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp
229 i386_linux_sigtramp_p (struct frame_info *this_frame)
231 CORE_ADDR pc = get_frame_pc (this_frame);
234 find_pc_partial_function (pc, &name, NULL, NULL);
236 /* If we have NAME, we can optimize the search. The trampolines are
237 named __restore and __restore_rt. However, they aren't dynamically
238 exported from the shared C library, so the trampoline may appear to
239 be part of the preceding function. This should always be sigaction,
240 __sigaction, or __libc_sigaction (all aliases to the same function). */
241 if (name == NULL || strstr (name, "sigaction") != NULL)
242 return (i386_linux_sigtramp_start (this_frame) != 0
243 || i386_linux_rt_sigtramp_start (this_frame) != 0);
245 return (strcmp ("__restore", name) == 0
246 || strcmp ("__restore_rt", name) == 0);
249 /* Return one if the PC of THIS_FRAME is in a signal trampoline which
250 may have DWARF-2 CFI. */
253 i386_linux_dwarf_signal_frame_p (struct gdbarch *gdbarch,
254 struct frame_info *this_frame)
256 CORE_ADDR pc = get_frame_pc (this_frame);
259 find_pc_partial_function (pc, &name, NULL, NULL);
261 /* If a vsyscall DSO is in use, the signal trampolines may have these
263 if (name && (strcmp (name, "__kernel_sigreturn") == 0
264 || strcmp (name, "__kernel_rt_sigreturn") == 0))
270 /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
271 #define I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 20
273 /* Assuming THIS_FRAME is a GNU/Linux sigtramp routine, return the
274 address of the associated sigcontext structure. */
277 i386_linux_sigcontext_addr (struct frame_info *this_frame)
279 struct gdbarch *gdbarch = get_frame_arch (this_frame);
280 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
285 get_frame_register (this_frame, I386_ESP_REGNUM, buf);
286 sp = extract_unsigned_integer (buf, 4, byte_order);
288 pc = i386_linux_sigtramp_start (this_frame);
291 /* The sigcontext structure lives on the stack, right after
292 the signum argument. We determine the address of the
293 sigcontext structure by looking at the frame's stack
294 pointer. Keep in mind that the first instruction of the
295 sigtramp code is "pop %eax". If the PC is after this
296 instruction, adjust the returned value accordingly. */
297 if (pc == get_frame_pc (this_frame))
302 pc = i386_linux_rt_sigtramp_start (this_frame);
305 CORE_ADDR ucontext_addr;
307 /* The sigcontext structure is part of the user context. A
308 pointer to the user context is passed as the third argument
309 to the signal handler. */
310 read_memory (sp + 8, buf, 4);
311 ucontext_addr = extract_unsigned_integer (buf, 4, byte_order);
312 return ucontext_addr + I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
315 error (_("Couldn't recognize signal trampoline."));
319 /* Set the program counter for process PTID to PC. */
322 i386_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
324 regcache_cooked_write_unsigned (regcache, I386_EIP_REGNUM, pc);
326 /* We must be careful with modifying the program counter. If we
327 just interrupted a system call, the kernel might try to restart
328 it when we resume the inferior. On restarting the system call,
329 the kernel will try backing up the program counter even though it
330 no longer points at the system call. This typically results in a
331 SIGSEGV or SIGILL. We can prevent this by writing `-1' in the
332 "orig_eax" pseudo-register.
334 Note that "orig_eax" is saved when setting up a dummy call frame.
335 This means that it is properly restored when that frame is
336 popped, and that the interrupted system call will be restarted
337 when we resume the inferior on return from a function call from
338 within GDB. In all other cases the system call will not be
340 regcache_cooked_write_unsigned (regcache, I386_LINUX_ORIG_EAX_REGNUM, -1);
343 /* Record all registers but IP register for process-record. */
346 i386_all_but_ip_registers_record (struct regcache *regcache)
348 if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM))
350 if (record_full_arch_list_add_reg (regcache, I386_ECX_REGNUM))
352 if (record_full_arch_list_add_reg (regcache, I386_EDX_REGNUM))
354 if (record_full_arch_list_add_reg (regcache, I386_EBX_REGNUM))
356 if (record_full_arch_list_add_reg (regcache, I386_ESP_REGNUM))
358 if (record_full_arch_list_add_reg (regcache, I386_EBP_REGNUM))
360 if (record_full_arch_list_add_reg (regcache, I386_ESI_REGNUM))
362 if (record_full_arch_list_add_reg (regcache, I386_EDI_REGNUM))
364 if (record_full_arch_list_add_reg (regcache, I386_EFLAGS_REGNUM))
370 /* i386_canonicalize_syscall maps from the native i386 Linux set
371 of syscall ids into a canonical set of syscall ids used by
372 process record (a mostly trivial mapping, since the canonical
373 set was originally taken from the i386 set). */
375 static enum gdb_syscall
376 i386_canonicalize_syscall (int syscall)
378 enum { i386_syscall_max = 499 };
380 if (syscall <= i386_syscall_max)
381 return (enum gdb_syscall) syscall;
383 return gdb_sys_no_syscall;
386 /* Value of the sigcode in case of a boundary fault. */
388 #define SIG_CODE_BONDARY_FAULT 3
390 /* i386 GNU/Linux implementation of the handle_segmentation_fault
391 gdbarch hook. Displays information related to MPX bound
394 i386_linux_handle_segmentation_fault (struct gdbarch *gdbarch,
395 struct ui_out *uiout)
397 /* -Wmaybe-uninitialized */
398 CORE_ADDR lower_bound = 0, upper_bound = 0, access = 0;
402 if (!i386_mpx_enabled ())
407 /* Sigcode evaluates if the actual segfault is a boundary violation. */
408 sig_code = parse_and_eval_long ("$_siginfo.si_code\n");
411 = parse_and_eval_long ("$_siginfo._sifields._sigfault._addr_bnd._lower");
413 = parse_and_eval_long ("$_siginfo._sifields._sigfault._addr_bnd._upper");
415 = parse_and_eval_long ("$_siginfo._sifields._sigfault.si_addr");
417 CATCH (exception, RETURN_MASK_ALL)
423 /* If this is not a boundary violation just return. */
424 if (sig_code != SIG_CODE_BONDARY_FAULT)
427 is_upper = (access > upper_bound ? 1 : 0);
431 uiout->field_string ("sigcode-meaning", _("Upper bound violation"));
433 uiout->field_string ("sigcode-meaning", _("Lower bound violation"));
435 uiout->text (_(" while accessing address "));
436 uiout->field_fmt ("bound-access", "%s", paddress (gdbarch, access));
438 uiout->text (_("\nBounds: [lower = "));
439 uiout->field_fmt ("lower-bound", "%s", paddress (gdbarch, lower_bound));
441 uiout->text (_(", upper = "));
442 uiout->field_fmt ("upper-bound", "%s", paddress (gdbarch, upper_bound));
444 uiout->text (_("]"));
447 /* Parse the arguments of current system call instruction and record
448 the values of the registers and memory that will be changed into
449 "record_arch_list". This instruction is "int 0x80" (Linux
450 Kernel2.4) or "sysenter" (Linux Kernel 2.6).
452 Return -1 if something wrong. */
454 static struct linux_record_tdep i386_linux_record_tdep;
457 i386_linux_intx80_sysenter_syscall_record (struct regcache *regcache)
460 LONGEST syscall_native;
461 enum gdb_syscall syscall_gdb;
463 regcache_raw_read_signed (regcache, I386_EAX_REGNUM, &syscall_native);
465 syscall_gdb = i386_canonicalize_syscall (syscall_native);
469 printf_unfiltered (_("Process record and replay target doesn't "
470 "support syscall number %s\n"),
471 plongest (syscall_native));
475 if (syscall_gdb == gdb_sys_sigreturn
476 || syscall_gdb == gdb_sys_rt_sigreturn)
478 if (i386_all_but_ip_registers_record (regcache))
483 ret = record_linux_system_call (syscall_gdb, regcache,
484 &i386_linux_record_tdep);
488 /* Record the return value of the system call. */
489 if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM))
495 #define I386_LINUX_xstate 270
496 #define I386_LINUX_frame_size 732
499 i386_linux_record_signal (struct gdbarch *gdbarch,
500 struct regcache *regcache,
501 enum gdb_signal signal)
505 if (i386_all_but_ip_registers_record (regcache))
508 if (record_full_arch_list_add_reg (regcache, I386_EIP_REGNUM))
511 /* Record the change in the stack. */
512 regcache_raw_read_unsigned (regcache, I386_ESP_REGNUM, &esp);
513 /* This is for xstate.
514 sp -= sizeof (struct _fpstate); */
515 esp -= I386_LINUX_xstate;
516 /* This is for frame_size.
517 sp -= sizeof (struct rt_sigframe); */
518 esp -= I386_LINUX_frame_size;
519 if (record_full_arch_list_add_mem (esp,
520 I386_LINUX_xstate + I386_LINUX_frame_size))
523 if (record_full_arch_list_add_end ())
530 /* Core of the implementation for gdbarch get_syscall_number. Get pending
531 syscall number from REGCACHE. If there is no pending syscall -1 will be
532 returned. Pending syscall means ptrace has stepped into the syscall but
533 another ptrace call will step out. PC is right after the int $0x80
534 / syscall / sysenter instruction in both cases, PC does not change during
535 the second ptrace step. */
538 i386_linux_get_syscall_number_from_regcache (struct regcache *regcache)
540 struct gdbarch *gdbarch = regcache->arch ();
541 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
542 /* The content of a register. */
547 /* Getting the system call number from the register.
548 When dealing with x86 architecture, this information
549 is stored at %eax register. */
550 regcache->cooked_read (I386_LINUX_ORIG_EAX_REGNUM, buf);
552 ret = extract_signed_integer (buf, 4, byte_order);
557 /* Wrapper for i386_linux_get_syscall_number_from_regcache to make it
558 compatible with gdbarch get_syscall_number method prototype. */
561 i386_linux_get_syscall_number (struct gdbarch *gdbarch,
564 struct regcache *regcache = get_thread_regcache (thread);
566 return i386_linux_get_syscall_number_from_regcache (regcache);
569 /* The register sets used in GNU/Linux ELF core-dumps are identical to
570 the register sets in `struct user' that are used for a.out
571 core-dumps. These are also used by ptrace(2). The corresponding
572 types are `elf_gregset_t' for the general-purpose registers (with
573 `elf_greg_t' the type of a single GP register) and `elf_fpregset_t'
574 for the floating-point registers.
576 Those types used to be available under the names `gregset_t' and
577 `fpregset_t' too, and GDB used those names in the past. But those
578 names are now used for the register sets used in the `mcontext_t'
579 type, which have a different size and layout. */
581 /* Mapping between the general-purpose registers in `struct user'
582 format and GDB's register cache layout. */
584 /* From <sys/reg.h>. */
585 int i386_linux_gregset_reg_offset[] =
596 14 * 4, /* %eflags */
603 -1, -1, -1, -1, -1, -1, -1, -1,
604 -1, -1, -1, -1, -1, -1, -1, -1,
605 -1, -1, -1, -1, -1, -1, -1, -1,
607 -1, -1, -1, -1, -1, -1, -1, -1,
608 -1, -1, -1, -1, /* MPX registers BND0 ... BND3. */
609 -1, -1, /* MPX registers BNDCFGU, BNDSTATUS. */
610 -1, -1, -1, -1, -1, -1, -1, -1, /* k0 ... k7 (AVX512) */
611 -1, -1, -1, -1, -1, -1, -1, -1, /* zmm0 ... zmm7 (AVX512) */
612 -1, /* PKRU register */
613 11 * 4, /* "orig_eax" */
616 /* Mapping between the general-purpose registers in `struct
617 sigcontext' format and GDB's register cache layout. */
619 /* From <asm/sigcontext.h>. */
620 static int i386_linux_sc_reg_offset[] =
631 16 * 4, /* %eflags */
640 /* Get XSAVE extended state xcr0 from core dump. */
643 i386_linux_core_read_xcr0 (bfd *abfd)
645 asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate");
650 size_t size = bfd_section_size (abfd, xstate);
652 /* Check extended state size. */
653 if (size < X86_XSTATE_AVX_SIZE)
654 xcr0 = X86_XSTATE_SSE_MASK;
659 if (! bfd_get_section_contents (abfd, xstate, contents,
660 I386_LINUX_XSAVE_XCR0_OFFSET,
663 warning (_("Couldn't read `xcr0' bytes from "
664 "`.reg-xstate' section in core file."));
668 xcr0 = bfd_get_64 (abfd, contents);
677 /* See i386-linux-tdep.h. */
679 const struct target_desc *
680 i386_linux_read_description (uint64_t xcr0)
685 static struct target_desc *i386_linux_tdescs \
686 [2/*X87*/][2/*SSE*/][2/*AVX*/][2/*MPX*/][2/*AVX512*/][2/*PKRU*/] = {};
687 struct target_desc **tdesc;
689 tdesc = &i386_linux_tdescs[(xcr0 & X86_XSTATE_X87) ? 1 : 0]
690 [(xcr0 & X86_XSTATE_SSE) ? 1 : 0]
691 [(xcr0 & X86_XSTATE_AVX) ? 1 : 0]
692 [(xcr0 & X86_XSTATE_MPX) ? 1 : 0]
693 [(xcr0 & X86_XSTATE_AVX512) ? 1 : 0]
694 [(xcr0 & X86_XSTATE_PKRU) ? 1 : 0];
697 *tdesc = i386_create_target_description (xcr0, true);
702 /* Get Linux/x86 target description from core dump. */
704 static const struct target_desc *
705 i386_linux_core_read_description (struct gdbarch *gdbarch,
706 struct target_ops *target,
710 uint64_t xcr0 = i386_linux_core_read_xcr0 (abfd);
711 const struct target_desc *tdesc = i386_linux_read_description (xcr0);
716 if (bfd_get_section_by_name (abfd, ".reg-xfp") != NULL)
717 return i386_linux_read_description (X86_XSTATE_SSE_MASK);
719 return i386_linux_read_description (X86_XSTATE_X87_MASK);
722 /* Similar to i386_supply_fpregset, but use XSAVE extended state. */
725 i386_linux_supply_xstateregset (const struct regset *regset,
726 struct regcache *regcache, int regnum,
727 const void *xstateregs, size_t len)
729 i387_supply_xsave (regcache, regnum, xstateregs);
733 x86_linux_get_siginfo_type (struct gdbarch *gdbarch)
735 return linux_get_siginfo_type_with_fields (gdbarch, LINUX_SIGINFO_FIELD_ADDR_BND);
738 /* Similar to i386_collect_fpregset, but use XSAVE extended state. */
741 i386_linux_collect_xstateregset (const struct regset *regset,
742 const struct regcache *regcache,
743 int regnum, void *xstateregs, size_t len)
745 i387_collect_xsave (regcache, regnum, xstateregs, 1);
748 /* Register set definitions. */
750 static const struct regset i386_linux_xstateregset =
753 i386_linux_supply_xstateregset,
754 i386_linux_collect_xstateregset
757 /* Iterate over core file register note sections. */
760 i386_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
761 iterate_over_regset_sections_cb *cb,
763 const struct regcache *regcache)
765 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
767 cb (".reg", 68, 68, &i386_gregset, NULL, cb_data);
769 if (tdep->xcr0 & X86_XSTATE_AVX)
770 cb (".reg-xstate", X86_XSTATE_SIZE (tdep->xcr0),
771 X86_XSTATE_SIZE (tdep->xcr0), &i386_linux_xstateregset,
772 "XSAVE extended state", cb_data);
773 else if (tdep->xcr0 & X86_XSTATE_SSE)
774 cb (".reg-xfp", 512, 512, &i386_fpregset, "extended floating-point",
777 cb (".reg2", 108, 108, &i386_fpregset, NULL, cb_data);
780 /* Linux kernel shows PC value after the 'int $0x80' instruction even if
781 inferior is still inside the syscall. On next PTRACE_SINGLESTEP it will
782 finish the syscall but PC will not change.
784 Some vDSOs contain 'int $0x80; ret' and during stepping out of the syscall
785 i386_displaced_step_fixup would keep PC at the displaced pad location.
786 As PC is pointing to the 'ret' instruction before the step
787 i386_displaced_step_fixup would expect inferior has just executed that 'ret'
788 and PC should not be adjusted. In reality it finished syscall instead and
789 PC should get relocated back to its vDSO address. Hide the 'ret'
790 instruction by 'nop' so that i386_displaced_step_fixup is not confused.
792 It is not fully correct as the bytes in struct displaced_step_closure will
793 not match the inferior code. But we would need some new flag in
794 displaced_step_closure otherwise to keep the state that syscall is finishing
795 for the later i386_displaced_step_fixup execution as the syscall execution
796 is already no longer detectable there. The new flag field would mean
797 i386-linux-tdep.c needs to wrap all the displacement methods of i386-tdep.c
798 which does not seem worth it. The same effect is achieved by patching that
799 'nop' instruction there instead. */
801 static struct displaced_step_closure *
802 i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
803 CORE_ADDR from, CORE_ADDR to,
804 struct regcache *regs)
806 displaced_step_closure *closure_
807 = i386_displaced_step_copy_insn (gdbarch, from, to, regs);
809 if (i386_linux_get_syscall_number_from_regcache (regs) != -1)
811 /* The closure returned by i386_displaced_step_copy_insn is simply a
812 buffer with a copy of the instruction. */
813 i386_displaced_step_closure *closure
814 = (i386_displaced_step_closure *) closure_;
817 closure->buf[0] = 0x90;
824 i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
826 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
827 const struct target_desc *tdesc = info.target_desc;
828 struct tdesc_arch_data *tdesc_data = info.tdesc_data;
829 const struct tdesc_feature *feature;
832 gdb_assert (tdesc_data);
834 linux_init_abi (info, gdbarch);
836 /* GNU/Linux uses ELF. */
837 i386_elf_init_abi (info, gdbarch);
839 /* Reserve a number for orig_eax. */
840 set_gdbarch_num_regs (gdbarch, I386_LINUX_NUM_REGS);
842 if (! tdesc_has_registers (tdesc))
843 tdesc = i386_linux_read_description (X86_XSTATE_SSE_MASK);
846 feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux");
850 valid_p = tdesc_numbered_register (feature, tdesc_data,
851 I386_LINUX_ORIG_EAX_REGNUM,
856 /* Add the %orig_eax register used for syscall restarting. */
857 set_gdbarch_write_pc (gdbarch, i386_linux_write_pc);
859 tdep->register_reggroup_p = i386_linux_register_reggroup_p;
861 tdep->gregset_reg_offset = i386_linux_gregset_reg_offset;
862 tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset);
863 tdep->sizeof_gregset = 17 * 4;
865 tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */
867 tdep->sigtramp_p = i386_linux_sigtramp_p;
868 tdep->sigcontext_addr = i386_linux_sigcontext_addr;
869 tdep->sc_reg_offset = i386_linux_sc_reg_offset;
870 tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset);
872 tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET;
874 set_gdbarch_process_record (gdbarch, i386_process_record);
875 set_gdbarch_process_record_signal (gdbarch, i386_linux_record_signal);
877 /* Initialize the i386_linux_record_tdep. */
878 /* These values are the size of the type that will be used in a system
879 call. They are obtained from Linux Kernel source. */
880 i386_linux_record_tdep.size_pointer
881 = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
882 i386_linux_record_tdep.size__old_kernel_stat = 32;
883 i386_linux_record_tdep.size_tms = 16;
884 i386_linux_record_tdep.size_loff_t = 8;
885 i386_linux_record_tdep.size_flock = 16;
886 i386_linux_record_tdep.size_oldold_utsname = 45;
887 i386_linux_record_tdep.size_ustat = 20;
888 i386_linux_record_tdep.size_old_sigaction = 16;
889 i386_linux_record_tdep.size_old_sigset_t = 4;
890 i386_linux_record_tdep.size_rlimit = 8;
891 i386_linux_record_tdep.size_rusage = 72;
892 i386_linux_record_tdep.size_timeval = 8;
893 i386_linux_record_tdep.size_timezone = 8;
894 i386_linux_record_tdep.size_old_gid_t = 2;
895 i386_linux_record_tdep.size_old_uid_t = 2;
896 i386_linux_record_tdep.size_fd_set = 128;
897 i386_linux_record_tdep.size_old_dirent = 268;
898 i386_linux_record_tdep.size_statfs = 64;
899 i386_linux_record_tdep.size_statfs64 = 84;
900 i386_linux_record_tdep.size_sockaddr = 16;
901 i386_linux_record_tdep.size_int
902 = gdbarch_int_bit (gdbarch) / TARGET_CHAR_BIT;
903 i386_linux_record_tdep.size_long
904 = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
905 i386_linux_record_tdep.size_ulong
906 = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT;
907 i386_linux_record_tdep.size_msghdr = 28;
908 i386_linux_record_tdep.size_itimerval = 16;
909 i386_linux_record_tdep.size_stat = 88;
910 i386_linux_record_tdep.size_old_utsname = 325;
911 i386_linux_record_tdep.size_sysinfo = 64;
912 i386_linux_record_tdep.size_msqid_ds = 88;
913 i386_linux_record_tdep.size_shmid_ds = 84;
914 i386_linux_record_tdep.size_new_utsname = 390;
915 i386_linux_record_tdep.size_timex = 128;
916 i386_linux_record_tdep.size_mem_dqinfo = 24;
917 i386_linux_record_tdep.size_if_dqblk = 68;
918 i386_linux_record_tdep.size_fs_quota_stat = 68;
919 i386_linux_record_tdep.size_timespec = 8;
920 i386_linux_record_tdep.size_pollfd = 8;
921 i386_linux_record_tdep.size_NFS_FHSIZE = 32;
922 i386_linux_record_tdep.size_knfsd_fh = 132;
923 i386_linux_record_tdep.size_TASK_COMM_LEN = 16;
924 i386_linux_record_tdep.size_sigaction = 20;
925 i386_linux_record_tdep.size_sigset_t = 8;
926 i386_linux_record_tdep.size_siginfo_t = 128;
927 i386_linux_record_tdep.size_cap_user_data_t = 12;
928 i386_linux_record_tdep.size_stack_t = 12;
929 i386_linux_record_tdep.size_off_t = i386_linux_record_tdep.size_long;
930 i386_linux_record_tdep.size_stat64 = 96;
931 i386_linux_record_tdep.size_gid_t = 4;
932 i386_linux_record_tdep.size_uid_t = 4;
933 i386_linux_record_tdep.size_PAGE_SIZE = 4096;
934 i386_linux_record_tdep.size_flock64 = 24;
935 i386_linux_record_tdep.size_user_desc = 16;
936 i386_linux_record_tdep.size_io_event = 32;
937 i386_linux_record_tdep.size_iocb = 64;
938 i386_linux_record_tdep.size_epoll_event = 12;
939 i386_linux_record_tdep.size_itimerspec
940 = i386_linux_record_tdep.size_timespec * 2;
941 i386_linux_record_tdep.size_mq_attr = 32;
942 i386_linux_record_tdep.size_termios = 36;
943 i386_linux_record_tdep.size_termios2 = 44;
944 i386_linux_record_tdep.size_pid_t = 4;
945 i386_linux_record_tdep.size_winsize = 8;
946 i386_linux_record_tdep.size_serial_struct = 60;
947 i386_linux_record_tdep.size_serial_icounter_struct = 80;
948 i386_linux_record_tdep.size_hayes_esp_config = 12;
949 i386_linux_record_tdep.size_size_t = 4;
950 i386_linux_record_tdep.size_iovec = 8;
951 i386_linux_record_tdep.size_time_t = 4;
953 /* These values are the second argument of system call "sys_ioctl".
954 They are obtained from Linux Kernel source. */
955 i386_linux_record_tdep.ioctl_TCGETS = 0x5401;
956 i386_linux_record_tdep.ioctl_TCSETS = 0x5402;
957 i386_linux_record_tdep.ioctl_TCSETSW = 0x5403;
958 i386_linux_record_tdep.ioctl_TCSETSF = 0x5404;
959 i386_linux_record_tdep.ioctl_TCGETA = 0x5405;
960 i386_linux_record_tdep.ioctl_TCSETA = 0x5406;
961 i386_linux_record_tdep.ioctl_TCSETAW = 0x5407;
962 i386_linux_record_tdep.ioctl_TCSETAF = 0x5408;
963 i386_linux_record_tdep.ioctl_TCSBRK = 0x5409;
964 i386_linux_record_tdep.ioctl_TCXONC = 0x540A;
965 i386_linux_record_tdep.ioctl_TCFLSH = 0x540B;
966 i386_linux_record_tdep.ioctl_TIOCEXCL = 0x540C;
967 i386_linux_record_tdep.ioctl_TIOCNXCL = 0x540D;
968 i386_linux_record_tdep.ioctl_TIOCSCTTY = 0x540E;
969 i386_linux_record_tdep.ioctl_TIOCGPGRP = 0x540F;
970 i386_linux_record_tdep.ioctl_TIOCSPGRP = 0x5410;
971 i386_linux_record_tdep.ioctl_TIOCOUTQ = 0x5411;
972 i386_linux_record_tdep.ioctl_TIOCSTI = 0x5412;
973 i386_linux_record_tdep.ioctl_TIOCGWINSZ = 0x5413;
974 i386_linux_record_tdep.ioctl_TIOCSWINSZ = 0x5414;
975 i386_linux_record_tdep.ioctl_TIOCMGET = 0x5415;
976 i386_linux_record_tdep.ioctl_TIOCMBIS = 0x5416;
977 i386_linux_record_tdep.ioctl_TIOCMBIC = 0x5417;
978 i386_linux_record_tdep.ioctl_TIOCMSET = 0x5418;
979 i386_linux_record_tdep.ioctl_TIOCGSOFTCAR = 0x5419;
980 i386_linux_record_tdep.ioctl_TIOCSSOFTCAR = 0x541A;
981 i386_linux_record_tdep.ioctl_FIONREAD = 0x541B;
982 i386_linux_record_tdep.ioctl_TIOCINQ = i386_linux_record_tdep.ioctl_FIONREAD;
983 i386_linux_record_tdep.ioctl_TIOCLINUX = 0x541C;
984 i386_linux_record_tdep.ioctl_TIOCCONS = 0x541D;
985 i386_linux_record_tdep.ioctl_TIOCGSERIAL = 0x541E;
986 i386_linux_record_tdep.ioctl_TIOCSSERIAL = 0x541F;
987 i386_linux_record_tdep.ioctl_TIOCPKT = 0x5420;
988 i386_linux_record_tdep.ioctl_FIONBIO = 0x5421;
989 i386_linux_record_tdep.ioctl_TIOCNOTTY = 0x5422;
990 i386_linux_record_tdep.ioctl_TIOCSETD = 0x5423;
991 i386_linux_record_tdep.ioctl_TIOCGETD = 0x5424;
992 i386_linux_record_tdep.ioctl_TCSBRKP = 0x5425;
993 i386_linux_record_tdep.ioctl_TIOCTTYGSTRUCT = 0x5426;
994 i386_linux_record_tdep.ioctl_TIOCSBRK = 0x5427;
995 i386_linux_record_tdep.ioctl_TIOCCBRK = 0x5428;
996 i386_linux_record_tdep.ioctl_TIOCGSID = 0x5429;
997 i386_linux_record_tdep.ioctl_TCGETS2 = 0x802c542a;
998 i386_linux_record_tdep.ioctl_TCSETS2 = 0x402c542b;
999 i386_linux_record_tdep.ioctl_TCSETSW2 = 0x402c542c;
1000 i386_linux_record_tdep.ioctl_TCSETSF2 = 0x402c542d;
1001 i386_linux_record_tdep.ioctl_TIOCGPTN = 0x80045430;
1002 i386_linux_record_tdep.ioctl_TIOCSPTLCK = 0x40045431;
1003 i386_linux_record_tdep.ioctl_FIONCLEX = 0x5450;
1004 i386_linux_record_tdep.ioctl_FIOCLEX = 0x5451;
1005 i386_linux_record_tdep.ioctl_FIOASYNC = 0x5452;
1006 i386_linux_record_tdep.ioctl_TIOCSERCONFIG = 0x5453;
1007 i386_linux_record_tdep.ioctl_TIOCSERGWILD = 0x5454;
1008 i386_linux_record_tdep.ioctl_TIOCSERSWILD = 0x5455;
1009 i386_linux_record_tdep.ioctl_TIOCGLCKTRMIOS = 0x5456;
1010 i386_linux_record_tdep.ioctl_TIOCSLCKTRMIOS = 0x5457;
1011 i386_linux_record_tdep.ioctl_TIOCSERGSTRUCT = 0x5458;
1012 i386_linux_record_tdep.ioctl_TIOCSERGETLSR = 0x5459;
1013 i386_linux_record_tdep.ioctl_TIOCSERGETMULTI = 0x545A;
1014 i386_linux_record_tdep.ioctl_TIOCSERSETMULTI = 0x545B;
1015 i386_linux_record_tdep.ioctl_TIOCMIWAIT = 0x545C;
1016 i386_linux_record_tdep.ioctl_TIOCGICOUNT = 0x545D;
1017 i386_linux_record_tdep.ioctl_TIOCGHAYESESP = 0x545E;
1018 i386_linux_record_tdep.ioctl_TIOCSHAYESESP = 0x545F;
1019 i386_linux_record_tdep.ioctl_FIOQSIZE = 0x5460;
1021 /* These values are the second argument of system call "sys_fcntl"
1022 and "sys_fcntl64". They are obtained from Linux Kernel source. */
1023 i386_linux_record_tdep.fcntl_F_GETLK = 5;
1024 i386_linux_record_tdep.fcntl_F_GETLK64 = 12;
1025 i386_linux_record_tdep.fcntl_F_SETLK64 = 13;
1026 i386_linux_record_tdep.fcntl_F_SETLKW64 = 14;
1028 i386_linux_record_tdep.arg1 = I386_EBX_REGNUM;
1029 i386_linux_record_tdep.arg2 = I386_ECX_REGNUM;
1030 i386_linux_record_tdep.arg3 = I386_EDX_REGNUM;
1031 i386_linux_record_tdep.arg4 = I386_ESI_REGNUM;
1032 i386_linux_record_tdep.arg5 = I386_EDI_REGNUM;
1033 i386_linux_record_tdep.arg6 = I386_EBP_REGNUM;
1035 tdep->i386_intx80_record = i386_linux_intx80_sysenter_syscall_record;
1036 tdep->i386_sysenter_record = i386_linux_intx80_sysenter_syscall_record;
1037 tdep->i386_syscall_record = i386_linux_intx80_sysenter_syscall_record;
1039 /* N_FUN symbols in shared libaries have 0 for their values and need
1041 set_gdbarch_sofun_address_maybe_missing (gdbarch, 1);
1043 /* GNU/Linux uses SVR4-style shared libraries. */
1044 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
1045 set_solib_svr4_fetch_link_map_offsets
1046 (gdbarch, svr4_ilp32_fetch_link_map_offsets);
1048 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */
1049 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
1051 dwarf2_frame_set_signal_frame_p (gdbarch, i386_linux_dwarf_signal_frame_p);
1053 /* Enable TLS support. */
1054 set_gdbarch_fetch_tls_load_module_address (gdbarch,
1055 svr4_fetch_objfile_link_map);
1057 /* Core file support. */
1058 set_gdbarch_iterate_over_regset_sections
1059 (gdbarch, i386_linux_iterate_over_regset_sections);
1060 set_gdbarch_core_read_description (gdbarch,
1061 i386_linux_core_read_description);
1063 /* Displaced stepping. */
1064 set_gdbarch_displaced_step_copy_insn (gdbarch,
1065 i386_linux_displaced_step_copy_insn);
1066 set_gdbarch_displaced_step_fixup (gdbarch, i386_displaced_step_fixup);
1067 set_gdbarch_displaced_step_location (gdbarch,
1068 linux_displaced_step_location);
1070 /* Functions for 'catch syscall'. */
1071 set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_I386);
1072 set_gdbarch_get_syscall_number (gdbarch,
1073 i386_linux_get_syscall_number);
1075 set_gdbarch_get_siginfo_type (gdbarch, x86_linux_get_siginfo_type);
1076 set_gdbarch_handle_segmentation_fault (gdbarch,
1077 i386_linux_handle_segmentation_fault);
1081 _initialize_i386_linux_tdep (void)
1083 gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX,
1084 i386_linux_init_abi);
1092 { "i386/i386-linux.xml", X86_XSTATE_SSE_MASK },
1093 { "i386/i386-mmx-linux.xml", X86_XSTATE_X87_MASK },
1094 { "i386/i386-avx-linux.xml", X86_XSTATE_AVX_MASK },
1095 { "i386/i386-mpx-linux.xml", X86_XSTATE_MPX_MASK },
1096 { "i386/i386-avx-mpx-linux.xml", X86_XSTATE_AVX_MPX_MASK },
1097 { "i386/i386-avx-avx512-linux.xml", X86_XSTATE_AVX_AVX512_MASK },
1098 { "i386/i386-avx-mpx-avx512-pku-linux.xml",
1099 X86_XSTATE_AVX_MPX_AVX512_PKU_MASK },
1102 for (auto &a : xml_masks)
1104 auto tdesc = i386_linux_read_description (a.mask);
1106 selftests::record_xml_tdesc (a.xml, tdesc);
1108 #endif /* GDB_SELF_TEST */