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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[] = { | |
b64bbf8c | 38 | /* mov $__NR_rt_sigreturn,%rax */ |
baed091b ML |
39 | LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00, |
40 | /* syscall */ | |
41 | LINUX_SIGTRAMP_INSN1, 0x05 | |
53e95fcf JS |
42 | }; |
43 | ||
44 | #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) | |
45 | ||
46 | /* If PC is in a sigtramp routine, return the address of the start of | |
47 | the routine. Otherwise, return 0. */ | |
48 | ||
49 | static CORE_ADDR | |
50 | x86_64_linux_sigtramp_start (CORE_ADDR pc) | |
51 | { | |
52 | unsigned char buf[LINUX_SIGTRAMP_LEN]; | |
53 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
54 | return 0; | |
55 | ||
56 | if (buf[0] != LINUX_SIGTRAMP_INSN0) | |
57 | { | |
58 | if (buf[0] != LINUX_SIGTRAMP_INSN1) | |
59 | return 0; | |
60 | ||
61 | pc -= LINUX_SIGTRAMP_OFFSET1; | |
62 | ||
63 | if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0) | |
64 | return 0; | |
65 | } | |
66 | ||
67 | if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) | |
68 | return 0; | |
69 | ||
70 | return pc; | |
71 | } | |
72 | ||
baed091b | 73 | #define LINUX_SIGINFO_SIZE 0 |
c74ae012 | 74 | |
53e95fcf | 75 | /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ |
baed091b ML |
76 | #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40 |
77 | ||
78 | /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */ | |
79 | #define LINUX_SIGCONTEXT_PC_OFFSET 128 | |
80 | #define LINUX_SIGCONTEXT_FP_OFFSET 120 | |
53e95fcf | 81 | |
a4b6fc86 AC |
82 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
83 | address of the associated sigcontext structure. */ | |
baed091b | 84 | static CORE_ADDR |
53e95fcf JS |
85 | x86_64_linux_sigcontext_addr (struct frame_info *frame) |
86 | { | |
87 | CORE_ADDR pc; | |
baed091b | 88 | ULONGEST rsp; |
53e95fcf JS |
89 | |
90 | pc = x86_64_linux_sigtramp_start (frame->pc); | |
91 | if (pc) | |
92 | { | |
93 | if (frame->next) | |
94 | /* If this isn't the top frame, the next frame must be for the | |
95 | signal handler itself. The sigcontext structure is part of | |
96 | the user context. */ | |
c74ae012 | 97 | return frame->next->frame + LINUX_SIGINFO_SIZE + |
53e95fcf JS |
98 | LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
99 | ||
100 | ||
101 | /* This is the top frame. */ | |
baed091b | 102 | rsp = read_register (SP_REGNUM); |
b64bbf8c | 103 | return rsp + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; |
53e95fcf JS |
104 | |
105 | } | |
106 | ||
107 | error ("Couldn't recognize signal trampoline."); | |
108 | return 0; | |
109 | } | |
110 | ||
a4b6fc86 AC |
111 | /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the |
112 | saved program counter. */ | |
53e95fcf | 113 | |
baed091b | 114 | static CORE_ADDR |
53e95fcf JS |
115 | x86_64_linux_sigtramp_saved_pc (struct frame_info *frame) |
116 | { | |
117 | CORE_ADDR addr; | |
118 | ||
119 | addr = x86_64_linux_sigcontext_addr (frame); | |
120 | return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); | |
121 | } | |
122 | ||
123 | /* Immediately after a function call, return the saved pc. */ | |
124 | ||
125 | CORE_ADDR | |
126 | x86_64_linux_saved_pc_after_call (struct frame_info *frame) | |
127 | { | |
128 | if (frame->signal_handler_caller) | |
129 | return x86_64_linux_sigtramp_saved_pc (frame); | |
130 | ||
131 | return read_memory_integer (read_register (SP_REGNUM), 8); | |
132 | } | |
133 | ||
134 | /* Saved Pc. Get it from sigcontext if within sigtramp. */ | |
135 | CORE_ADDR | |
136 | x86_64_linux_frame_saved_pc (struct frame_info *frame) | |
137 | { | |
138 | if (frame->signal_handler_caller) | |
139 | return x86_64_linux_sigtramp_saved_pc (frame); | |
140 | return cfi_get_ra (frame); | |
141 | } | |
baed091b ML |
142 | |
143 | /* Return whether PC is in a GNU/Linux sigtramp routine. */ | |
144 | ||
145 | int | |
146 | x86_64_linux_in_sigtramp (CORE_ADDR pc, char *name) | |
147 | { | |
148 | if (name) | |
149 | return STREQ ("__restore_rt", name); | |
b64bbf8c | 150 | |
baed091b ML |
151 | return (x86_64_linux_sigtramp_start (pc) != 0); |
152 | } | |
153 | ||
154 | CORE_ADDR | |
155 | x86_64_linux_frame_chain (struct frame_info *fi) | |
156 | { | |
b64bbf8c ML |
157 | ULONGEST addr; |
158 | CORE_ADDR fp, pc; | |
159 | ||
160 | if (!fi->signal_handler_caller) | |
161 | { | |
162 | fp = cfi_frame_chain (fi); | |
163 | if (fp) | |
baed091b | 164 | return fp; |
b64bbf8c ML |
165 | else |
166 | addr = fi->frame; | |
167 | } | |
168 | else | |
169 | addr = fi->next->frame; | |
170 | ||
171 | addr += LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; | |
172 | ||
173 | fp = read_memory_integer (addr + LINUX_SIGCONTEXT_FP_OFFSET, 8) + 8; | |
174 | ||
175 | return fp; | |
baed091b ML |
176 | } |
177 | ||
178 | void | |
179 | x86_64_init_frame_pc (int fromleaf, struct frame_info *fi) | |
180 | { | |
b64bbf8c ML |
181 | CORE_ADDR addr; |
182 | ||
183 | if (fi->next && fi->next->signal_handler_caller) | |
184 | { | |
185 | addr = fi->next->next->frame | |
186 | + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET; | |
187 | fi->pc = read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8); | |
188 | } | |
189 | else | |
190 | cfi_init_frame_pc (fromleaf, fi); | |
baed091b ML |
191 | } |
192 | ||
193 | void | |
194 | x86_64_init_extra_frame_info (int fromleaf, struct frame_info *fi) | |
195 | { | |
b64bbf8c | 196 | cfi_init_extra_frame_info (fromleaf, fi); |
baed091b | 197 | } |