| 1 | /* Target-dependent code for GNU/Linux running on x86-64, for GDB. |
| 2 | |
| 3 | Copyright 2001 Free Software Foundation, Inc. |
| 4 | |
| 5 | Contributed by Jiri Smid, SuSE Labs. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 2 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program; if not, write to the Free Software |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "inferior.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "regcache.h" |
| 28 | #include "x86-64-tdep.h" |
| 29 | #include "dwarf2cfi.h" |
| 30 | |
| 31 | #define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */ |
| 32 | #define LINUX_SIGTRAMP_OFFSET0 (0) |
| 33 | #define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */ |
| 34 | #define LINUX_SIGTRAMP_OFFSET1 (7) |
| 35 | |
| 36 | static const unsigned char linux_sigtramp_code[] = { |
| 37 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */ |
| 38 | LINUX_SIGTRAMP_INSN1, 0x05 /* syscall */ |
| 39 | }; |
| 40 | |
| 41 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) |
| 42 | |
| 43 | /* If PC is in a sigtramp routine, return the address of the start of |
| 44 | the routine. Otherwise, return 0. */ |
| 45 | |
| 46 | static CORE_ADDR |
| 47 | x86_64_linux_sigtramp_start (CORE_ADDR pc) |
| 48 | { |
| 49 | unsigned char buf[LINUX_SIGTRAMP_LEN]; |
| 50 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 51 | return 0; |
| 52 | |
| 53 | if (buf[0] != LINUX_SIGTRAMP_INSN0) |
| 54 | { |
| 55 | if (buf[0] != LINUX_SIGTRAMP_INSN1) |
| 56 | return 0; |
| 57 | |
| 58 | pc -= LINUX_SIGTRAMP_OFFSET1; |
| 59 | |
| 60 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 61 | return 0; |
| 62 | } |
| 63 | |
| 64 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) |
| 65 | return 0; |
| 66 | |
| 67 | return pc; |
| 68 | } |
| 69 | |
| 70 | #define LINUX_SIGINFO_SIZE 128 |
| 71 | |
| 72 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
| 73 | #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36) |
| 74 | |
| 75 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 76 | address of the associated sigcontext structure. */ |
| 77 | CORE_ADDR |
| 78 | x86_64_linux_sigcontext_addr (struct frame_info *frame) |
| 79 | { |
| 80 | CORE_ADDR pc; |
| 81 | |
| 82 | pc = x86_64_linux_sigtramp_start (frame->pc); |
| 83 | if (pc) |
| 84 | { |
| 85 | if (frame->next) |
| 86 | /* If this isn't the top frame, the next frame must be for the |
| 87 | signal handler itself. The sigcontext structure is part of |
| 88 | the user context. */ |
| 89 | return frame->next->frame + LINUX_SIGINFO_SIZE + |
| 90 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 91 | |
| 92 | |
| 93 | /* This is the top frame. */ |
| 94 | return read_register (SP_REGNUM) + LINUX_SIGINFO_SIZE + |
| 95 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 96 | |
| 97 | } |
| 98 | |
| 99 | error ("Couldn't recognize signal trampoline."); |
| 100 | return 0; |
| 101 | } |
| 102 | |
| 103 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ |
| 104 | #define LINUX_SIGCONTEXT_PC_OFFSET (136) |
| 105 | |
| 106 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 107 | saved program counter. */ |
| 108 | |
| 109 | CORE_ADDR |
| 110 | x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) |
| 111 | { |
| 112 | CORE_ADDR addr; |
| 113 | |
| 114 | addr = x86_64_linux_sigcontext_addr (frame); |
| 115 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); |
| 116 | } |
| 117 | |
| 118 | /* Immediately after a function call, return the saved pc. */ |
| 119 | |
| 120 | CORE_ADDR |
| 121 | x86_64_linux_saved_pc_after_call (struct frame_info *frame) |
| 122 | { |
| 123 | if (frame->signal_handler_caller) |
| 124 | return x86_64_linux_sigtramp_saved_pc (frame); |
| 125 | |
| 126 | return read_memory_integer (read_register (SP_REGNUM), 8); |
| 127 | } |
| 128 | |
| 129 | /* Saved Pc. Get it from sigcontext if within sigtramp. */ |
| 130 | CORE_ADDR |
| 131 | x86_64_linux_frame_saved_pc (struct frame_info *frame) |
| 132 | { |
| 133 | if (frame->signal_handler_caller) |
| 134 | return x86_64_linux_sigtramp_saved_pc (frame); |
| 135 | return cfi_get_ra (frame); |
| 136 | } |