| 1 | /* Target-dependent code for GNU/Linux running on x86-64, for GDB. |
| 2 | |
| 3 | Copyright 2001, 2003 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 "gdb_string.h" |
| 28 | #include "regcache.h" |
| 29 | #include "x86-64-tdep.h" |
| 30 | #include "dwarf2cfi.h" |
| 31 | #include "osabi.h" |
| 32 | |
| 33 | #define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */ |
| 34 | #define LINUX_SIGTRAMP_OFFSET0 (0) |
| 35 | #define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */ |
| 36 | #define LINUX_SIGTRAMP_OFFSET1 (7) |
| 37 | |
| 38 | static const unsigned char linux_sigtramp_code[] = { |
| 39 | /* mov $__NR_rt_sigreturn,%rax */ |
| 40 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00, |
| 41 | /* syscall */ |
| 42 | LINUX_SIGTRAMP_INSN1, 0x05 |
| 43 | }; |
| 44 | |
| 45 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) |
| 46 | |
| 47 | /* If PC is in a sigtramp routine, return the address of the start of |
| 48 | the routine. Otherwise, return 0. */ |
| 49 | |
| 50 | static CORE_ADDR |
| 51 | x86_64_linux_sigtramp_start (CORE_ADDR pc) |
| 52 | { |
| 53 | unsigned char buf[LINUX_SIGTRAMP_LEN]; |
| 54 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 55 | return 0; |
| 56 | |
| 57 | if (buf[0] != LINUX_SIGTRAMP_INSN0) |
| 58 | { |
| 59 | if (buf[0] != LINUX_SIGTRAMP_INSN1) |
| 60 | return 0; |
| 61 | |
| 62 | pc -= LINUX_SIGTRAMP_OFFSET1; |
| 63 | |
| 64 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) |
| 65 | return 0; |
| 66 | } |
| 67 | |
| 68 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) |
| 69 | return 0; |
| 70 | |
| 71 | return pc; |
| 72 | } |
| 73 | |
| 74 | #define LINUX_SIGINFO_SIZE 0 |
| 75 | |
| 76 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
| 77 | #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 |
| 78 | |
| 79 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ |
| 80 | #define LINUX_SIGCONTEXT_PC_OFFSET 128 |
| 81 | #define LINUX_SIGCONTEXT_FP_OFFSET 120 |
| 82 | |
| 83 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 84 | address of the associated sigcontext structure. */ |
| 85 | static CORE_ADDR |
| 86 | x86_64_linux_sigcontext_addr (struct frame_info *frame) |
| 87 | { |
| 88 | CORE_ADDR pc; |
| 89 | ULONGEST rsp; |
| 90 | |
| 91 | pc = x86_64_linux_sigtramp_start (get_frame_pc (frame)); |
| 92 | if (pc) |
| 93 | { |
| 94 | if (get_next_frame (frame)) |
| 95 | /* If this isn't the top frame, the next frame must be for the |
| 96 | signal handler itself. The sigcontext structure is part of |
| 97 | the user context. */ |
| 98 | return get_frame_base (get_next_frame (frame)) + LINUX_SIGINFO_SIZE + |
| 99 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 100 | |
| 101 | |
| 102 | /* This is the top frame. */ |
| 103 | rsp = read_register (SP_REGNUM); |
| 104 | return rsp + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 105 | |
| 106 | } |
| 107 | |
| 108 | error ("Couldn't recognize signal trampoline."); |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
| 113 | saved program counter. */ |
| 114 | |
| 115 | static CORE_ADDR |
| 116 | x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) |
| 117 | { |
| 118 | CORE_ADDR addr; |
| 119 | |
| 120 | addr = x86_64_linux_sigcontext_addr (frame); |
| 121 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); |
| 122 | } |
| 123 | |
| 124 | /* Immediately after a function call, return the saved pc. */ |
| 125 | |
| 126 | CORE_ADDR |
| 127 | x86_64_linux_saved_pc_after_call (struct frame_info *frame) |
| 128 | { |
| 129 | if ((get_frame_type (frame) == SIGTRAMP_FRAME)) |
| 130 | return x86_64_linux_sigtramp_saved_pc (frame); |
| 131 | |
| 132 | return read_memory_integer (read_register (SP_REGNUM), 8); |
| 133 | } |
| 134 | |
| 135 | /* Saved Pc. Get it from sigcontext if within sigtramp. */ |
| 136 | CORE_ADDR |
| 137 | x86_64_linux_frame_saved_pc (struct frame_info *frame) |
| 138 | { |
| 139 | if ((get_frame_type (frame) == SIGTRAMP_FRAME)) |
| 140 | return x86_64_linux_sigtramp_saved_pc (frame); |
| 141 | return cfi_get_ra (frame); |
| 142 | } |
| 143 | |
| 144 | /* Return whether PC is in a GNU/Linux sigtramp routine. */ |
| 145 | |
| 146 | int |
| 147 | x86_64_linux_in_sigtramp (CORE_ADDR pc, char *name) |
| 148 | { |
| 149 | if (name) |
| 150 | return strcmp ("__restore_rt", name) == 0; |
| 151 | |
| 152 | return (x86_64_linux_sigtramp_start (pc) != 0); |
| 153 | } |
| 154 | |
| 155 | CORE_ADDR |
| 156 | x86_64_linux_frame_chain (struct frame_info *fi) |
| 157 | { |
| 158 | ULONGEST addr; |
| 159 | CORE_ADDR fp, pc; |
| 160 | |
| 161 | if (!(get_frame_type (fi) == SIGTRAMP_FRAME)) |
| 162 | { |
| 163 | fp = cfi_frame_chain (fi); |
| 164 | if (fp) |
| 165 | return fp; |
| 166 | else |
| 167 | addr = get_frame_base (fi); |
| 168 | } |
| 169 | else |
| 170 | addr = get_frame_base (get_next_frame (fi)); |
| 171 | |
| 172 | addr += LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 173 | |
| 174 | fp = read_memory_integer (addr + LINUX_SIGCONTEXT_FP_OFFSET, 8) + 8; |
| 175 | |
| 176 | return fp; |
| 177 | } |
| 178 | |
| 179 | CORE_ADDR |
| 180 | x86_64_init_frame_pc (int fromleaf, struct frame_info *fi) |
| 181 | { |
| 182 | CORE_ADDR addr; |
| 183 | |
| 184 | if (get_next_frame (fi) |
| 185 | && (get_frame_type (get_next_frame (fi)) == SIGTRAMP_FRAME)) |
| 186 | { |
| 187 | addr = get_frame_base (get_next_frame (get_next_frame (fi))) |
| 188 | + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
| 189 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); |
| 190 | } |
| 191 | else |
| 192 | return cfi_init_frame_pc (fromleaf, fi); |
| 193 | } |
| 194 | \f |
| 195 | |
| 196 | static void |
| 197 | x86_64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 198 | { |
| 199 | x86_64_init_abi (info, gdbarch); |
| 200 | } |
| 201 | |
| 202 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 203 | extern void _initialize_x86_64_linux_tdep (void); |
| 204 | |
| 205 | void |
| 206 | _initialize_x86_64_linux_tdep (void) |
| 207 | { |
| 208 | gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_LINUX, |
| 209 | x86_64_linux_init_abi); |
| 210 | } |