| /* Target-dependent code for GNU/Linux i386. |
| |
| Copyright (C) 2000-2021 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 "infrun.h" |
| |
| #include "i387-tdep.h" |
| #include "gdbsupport/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 "arch/i386.h" |
| #include "target-descriptions.h" |
| |
| /* 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)) |
| 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)) |
| 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)) |
| 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)) |
| 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 report_signal_info |
| gdbarch hook. Displays information related to MPX bound |
| violations. */ |
| void |
| i386_linux_report_signal_info (struct gdbarch *gdbarch, struct ui_out *uiout, |
| enum gdb_signal siggnal) |
| { |
| /* -Wmaybe-uninitialized */ |
| CORE_ADDR lower_bound = 0, upper_bound = 0, access = 0; |
| int is_upper; |
| long sig_code = 0; |
| |
| if (!i386_mpx_enabled () || siggnal != GDB_SIGNAL_SEGV) |
| 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 (const gdb_exception &exception) |
| { |
| return; |
| } |
| |
| /* 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_core_addr ("bound-access", gdbarch, access); |
| |
| uiout->text (_("\nBounds: [lower = ")); |
| uiout->field_core_addr ("lower-bound", gdbarch, lower_bound); |
| |
| uiout->text (_(", upper = ")); |
| uiout->field_core_addr ("upper-bound", 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 = regcache->arch (); |
| 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 (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, |
| thread_info *thread) |
| { |
| struct regcache *regcache = get_thread_regcache (thread); |
| |
| 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 (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) |
| { |
| if (xcr0 == 0) |
| return NULL; |
| |
| static struct target_desc *i386_linux_tdescs \ |
| [2/*X87*/][2/*SSE*/][2/*AVX*/][2/*MPX*/][2/*AVX512*/][2/*PKRU*/] = {}; |
| struct target_desc **tdesc; |
| |
| tdesc = &i386_linux_tdescs[(xcr0 & X86_XSTATE_X87) ? 1 : 0] |
| [(xcr0 & X86_XSTATE_SSE) ? 1 : 0] |
| [(xcr0 & X86_XSTATE_AVX) ? 1 : 0] |
| [(xcr0 & X86_XSTATE_MPX) ? 1 : 0] |
| [(xcr0 & X86_XSTATE_AVX512) ? 1 : 0] |
| [(xcr0 & X86_XSTATE_PKRU) ? 1 : 0]; |
| |
| if (*tdesc == NULL) |
| *tdesc = i386_create_target_description (xcr0, true, false); |
| |
| return *tdesc; |
| } |
| |
| /* 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, 68, &i386_gregset, NULL, cb_data); |
| |
| if (tdep->xcr0 & X86_XSTATE_AVX) |
| cb (".reg-xstate", X86_XSTATE_SIZE (tdep->xcr0), |
| X86_XSTATE_SIZE (tdep->xcr0), &i386_linux_xstateregset, |
| "XSAVE extended state", cb_data); |
| else if (tdep->xcr0 & X86_XSTATE_SSE) |
| cb (".reg-xfp", 512, 512, &i386_fpregset, "extended floating-point", |
| cb_data); |
| else |
| cb (".reg2", 108, 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_copy_insn_closure will not match the inferior code. But we |
| would need some new flag in displaced_step_copy_insn_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 displaced_step_copy_insn_closure_up |
| i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch, |
| CORE_ADDR from, CORE_ADDR to, |
| struct regcache *regs) |
| { |
| displaced_step_copy_insn_closure_up closure_ |
| = i386_displaced_step_copy_insn (gdbarch, from, to, regs); |
| |
| if (i386_linux_get_syscall_number_from_regcache (regs) != -1) |
| { |
| /* The closure returned by i386_displaced_step_copy_insn is simply a |
| buffer with a copy of the instruction. */ |
| i386_displaced_step_copy_insn_closure *closure |
| = (i386_displaced_step_copy_insn_closure *) closure_.get (); |
| |
| /* Fake nop. */ |
| closure->buf[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 = info.tdesc_data; |
| const struct tdesc_feature *feature; |
| int valid_p; |
| |
| gdb_assert (tdesc_data); |
| |
| linux_init_abi (info, gdbarch, 1); |
| |
| /* 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 libraries 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, linux_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); |
| |
| /* 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_report_signal_info (gdbarch, i386_linux_report_signal_info); |
| } |
| |
| void _initialize_i386_linux_tdep (); |
| void |
| _initialize_i386_linux_tdep () |
| { |
| gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX, |
| i386_linux_init_abi); |
| } |