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a4b6fc86 AC |
1 | /* Target-dependent code for GNU/Linux running on x86-64, for GDB. |
2 | ||
3 | Copyright 2001 Free Software Foundation, Inc. | |
4 | ||
53e95fcf JS |
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" | |
30d52491 | 27 | #include "gdb_string.h" |
53e95fcf JS |
28 | #include "regcache.h" |
29 | #include "x86-64-tdep.h" | |
30 | #include "dwarf2cfi.h" | |
31 | ||
53e95fcf JS |
32 | #define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */ |
33 | #define LINUX_SIGTRAMP_OFFSET0 (0) | |
34 | #define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */ | |
35 | #define LINUX_SIGTRAMP_OFFSET1 (7) | |
36 | ||
37 | static const unsigned char linux_sigtramp_code[] = { | |
38 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */ | |
39 | LINUX_SIGTRAMP_INSN1, 0x05 /* syscall */ | |
40 | }; | |
41 | ||
42 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) | |
43 | ||
44 | /* If PC is in a sigtramp routine, return the address of the start of | |
45 | the routine. Otherwise, return 0. */ | |
46 | ||
47 | static CORE_ADDR | |
48 | x86_64_linux_sigtramp_start (CORE_ADDR pc) | |
49 | { | |
50 | unsigned char buf[LINUX_SIGTRAMP_LEN]; | |
51 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
52 | return 0; | |
53 | ||
54 | if (buf[0] != LINUX_SIGTRAMP_INSN0) | |
55 | { | |
56 | if (buf[0] != LINUX_SIGTRAMP_INSN1) | |
57 | return 0; | |
58 | ||
59 | pc -= LINUX_SIGTRAMP_OFFSET1; | |
60 | ||
61 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
62 | return 0; | |
63 | } | |
64 | ||
65 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) | |
66 | return 0; | |
67 | ||
68 | return pc; | |
69 | } | |
70 | ||
c74ae012 JS |
71 | #define LINUX_SIGINFO_SIZE 128 |
72 | ||
53e95fcf JS |
73 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
74 | #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36) | |
75 | ||
a4b6fc86 AC |
76 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
77 | address of the associated sigcontext structure. */ | |
53e95fcf JS |
78 | CORE_ADDR |
79 | x86_64_linux_sigcontext_addr (struct frame_info *frame) | |
80 | { | |
81 | CORE_ADDR pc; | |
82 | ||
83 | pc = x86_64_linux_sigtramp_start (frame->pc); | |
84 | if (pc) | |
85 | { | |
86 | if (frame->next) | |
87 | /* If this isn't the top frame, the next frame must be for the | |
88 | signal handler itself. The sigcontext structure is part of | |
89 | the user context. */ | |
c74ae012 | 90 | return frame->next->frame + LINUX_SIGINFO_SIZE + |
53e95fcf JS |
91 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
92 | ||
93 | ||
94 | /* This is the top frame. */ | |
c74ae012 | 95 | return read_register (SP_REGNUM) + LINUX_SIGINFO_SIZE + |
53e95fcf JS |
96 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
97 | ||
98 | } | |
99 | ||
100 | error ("Couldn't recognize signal trampoline."); | |
101 | return 0; | |
102 | } | |
103 | ||
104 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ | |
105 | #define LINUX_SIGCONTEXT_PC_OFFSET (136) | |
106 | ||
a4b6fc86 AC |
107 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
108 | saved program counter. */ | |
53e95fcf JS |
109 | |
110 | CORE_ADDR | |
111 | x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) | |
112 | { | |
113 | CORE_ADDR addr; | |
114 | ||
115 | addr = x86_64_linux_sigcontext_addr (frame); | |
116 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); | |
117 | } | |
118 | ||
119 | /* Immediately after a function call, return the saved pc. */ | |
120 | ||
121 | CORE_ADDR | |
122 | x86_64_linux_saved_pc_after_call (struct frame_info *frame) | |
123 | { | |
124 | if (frame->signal_handler_caller) | |
125 | return x86_64_linux_sigtramp_saved_pc (frame); | |
126 | ||
127 | return read_memory_integer (read_register (SP_REGNUM), 8); | |
128 | } | |
129 | ||
130 | /* Saved Pc. Get it from sigcontext if within sigtramp. */ | |
131 | CORE_ADDR | |
132 | x86_64_linux_frame_saved_pc (struct frame_info *frame) | |
133 | { | |
134 | if (frame->signal_handler_caller) | |
135 | return x86_64_linux_sigtramp_saved_pc (frame); | |
136 | return cfi_get_ra (frame); | |
137 | } |