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53e95fcf JS |
1 | /* Target-dependent code for Linux running on x86-64, for GDB. |
2 | Copyright 2001 | |
3 | Free Software Foundation, Inc. | |
4 | Contributed by Jiri Smid, SuSE Labs. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "inferior.h" | |
25 | #include "gdbcore.h" | |
26 | #include "regcache.h" | |
27 | #include "x86-64-tdep.h" | |
28 | #include "dwarf2cfi.h" | |
29 | ||
53e95fcf JS |
30 | #define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */ |
31 | #define LINUX_SIGTRAMP_OFFSET0 (0) | |
32 | #define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */ | |
33 | #define LINUX_SIGTRAMP_OFFSET1 (7) | |
34 | ||
35 | static const unsigned char linux_sigtramp_code[] = { | |
36 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */ | |
37 | LINUX_SIGTRAMP_INSN1, 0x05 /* syscall */ | |
38 | }; | |
39 | ||
40 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) | |
41 | ||
42 | /* If PC is in a sigtramp routine, return the address of the start of | |
43 | the routine. Otherwise, return 0. */ | |
44 | ||
45 | static CORE_ADDR | |
46 | x86_64_linux_sigtramp_start (CORE_ADDR pc) | |
47 | { | |
48 | unsigned char buf[LINUX_SIGTRAMP_LEN]; | |
49 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
50 | return 0; | |
51 | ||
52 | if (buf[0] != LINUX_SIGTRAMP_INSN0) | |
53 | { | |
54 | if (buf[0] != LINUX_SIGTRAMP_INSN1) | |
55 | return 0; | |
56 | ||
57 | pc -= LINUX_SIGTRAMP_OFFSET1; | |
58 | ||
59 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
60 | return 0; | |
61 | } | |
62 | ||
63 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) | |
64 | return 0; | |
65 | ||
66 | return pc; | |
67 | } | |
68 | ||
c74ae012 JS |
69 | #define LINUX_SIGINFO_SIZE 128 |
70 | ||
53e95fcf JS |
71 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
72 | #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36) | |
73 | ||
74 | /* Assuming FRAME is for a Linux sigtramp routine, return the address | |
75 | of the associated sigcontext structure. */ | |
76 | CORE_ADDR | |
77 | x86_64_linux_sigcontext_addr (struct frame_info *frame) | |
78 | { | |
79 | CORE_ADDR pc; | |
80 | ||
81 | pc = x86_64_linux_sigtramp_start (frame->pc); | |
82 | if (pc) | |
83 | { | |
84 | if (frame->next) | |
85 | /* If this isn't the top frame, the next frame must be for the | |
86 | signal handler itself. The sigcontext structure is part of | |
87 | the user context. */ | |
c74ae012 | 88 | return frame->next->frame + LINUX_SIGINFO_SIZE + |
53e95fcf JS |
89 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
90 | ||
91 | ||
92 | /* This is the top frame. */ | |
c74ae012 | 93 | return read_register (SP_REGNUM) + LINUX_SIGINFO_SIZE + |
53e95fcf JS |
94 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
95 | ||
96 | } | |
97 | ||
98 | error ("Couldn't recognize signal trampoline."); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ | |
103 | #define LINUX_SIGCONTEXT_PC_OFFSET (136) | |
104 | ||
105 | /* Assuming FRAME is for a Linux sigtramp routine, return the saved | |
106 | program counter. */ | |
107 | ||
108 | CORE_ADDR | |
109 | x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) | |
110 | { | |
111 | CORE_ADDR addr; | |
112 | ||
113 | addr = x86_64_linux_sigcontext_addr (frame); | |
114 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); | |
115 | } | |
116 | ||
117 | /* Immediately after a function call, return the saved pc. */ | |
118 | ||
119 | CORE_ADDR | |
120 | x86_64_linux_saved_pc_after_call (struct frame_info *frame) | |
121 | { | |
122 | if (frame->signal_handler_caller) | |
123 | return x86_64_linux_sigtramp_saved_pc (frame); | |
124 | ||
125 | return read_memory_integer (read_register (SP_REGNUM), 8); | |
126 | } | |
127 | ||
128 | /* Saved Pc. Get it from sigcontext if within sigtramp. */ | |
129 | CORE_ADDR | |
130 | x86_64_linux_frame_saved_pc (struct frame_info *frame) | |
131 | { | |
132 | if (frame->signal_handler_caller) | |
133 | return x86_64_linux_sigtramp_saved_pc (frame); | |
134 | return cfi_get_ra (frame); | |
135 | } |