Commit | Line | Data |
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e0ca2bb9 | 1 | /* Target-dependent code for the GNU Hurd. |
b811d2c2 | 2 | Copyright (C) 2002-2020 Free Software Foundation, Inc. |
c906108c | 3 | |
c5aa993b | 4 | This file is part of GDB. |
c906108c | 5 | |
c5aa993b JM |
6 | This program is free software; you can redistribute it and/or modify |
7 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 8 | the Free Software Foundation; either version 3 of the License, or |
c5aa993b | 9 | (at your option) any later version. |
c906108c | 10 | |
c5aa993b JM |
11 | This program is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
c906108c | 15 | |
c5aa993b | 16 | You should have received a copy of the GNU General Public License |
a9762ec7 | 17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
c906108c | 18 | |
e0ca2bb9 | 19 | #include "defs.h" |
0af5e106 | 20 | #include "gdbcore.h" |
4be87837 | 21 | #include "osabi.h" |
8d005789 | 22 | #include "solib-svr4.h" |
c906108c | 23 | |
e0ca2bb9 MK |
24 | #include "i386-tdep.h" |
25 | ||
0af5e106 ST |
26 | /* Recognizing signal handler frames. */ |
27 | ||
28 | /* When the GNU/Hurd libc calls a signal handler, the return address points | |
29 | inside the trampoline assembly snippet. | |
30 | ||
31 | If the trampoline function name can not be identified, we resort to reading | |
32 | memory from the process in order to identify it. */ | |
33 | ||
34 | static const gdb_byte gnu_sigtramp_code[] = | |
35 | { | |
36 | /* rpc_wait_trampoline: */ | |
37 | 0xb8, 0xe7, 0xff, 0xff, 0xff, /* mov $-25,%eax */ | |
38 | 0x9a, 0x00, 0x00, 0x00, 0x00, 0x07, 0x00, /* lcall $7,$0 */ | |
39 | 0x89, 0x01, /* movl %eax, (%ecx) */ | |
40 | 0x89, 0xdc, /* movl %ebx, %esp */ | |
41 | ||
42 | /* trampoline: */ | |
43 | 0xff, 0xd2, /* call *%edx */ | |
44 | /* RA HERE */ | |
45 | 0x83, 0xc4, 0x0c, /* addl $12, %esp */ | |
46 | 0xc3, /* ret */ | |
47 | ||
48 | /* firewall: */ | |
49 | 0xf4, /* hlt */ | |
50 | }; | |
51 | ||
52 | #define GNU_SIGTRAMP_LEN (sizeof gnu_sigtramp_code) | |
53 | #define GNU_SIGTRAMP_TAIL 5 /* length of tail after RA */ | |
54 | ||
55 | /* If THIS_FRAME is a sigtramp routine, return the address of the | |
56 | start of the routine. Otherwise, return 0. */ | |
57 | ||
58 | static CORE_ADDR | |
59 | i386_gnu_sigtramp_start (struct frame_info *this_frame) | |
60 | { | |
61 | CORE_ADDR pc = get_frame_pc (this_frame); | |
62 | gdb_byte buf[GNU_SIGTRAMP_LEN]; | |
63 | ||
64 | if (!safe_frame_unwind_memory (this_frame, | |
65 | pc + GNU_SIGTRAMP_TAIL - GNU_SIGTRAMP_LEN, | |
66 | buf, GNU_SIGTRAMP_LEN)) | |
67 | return 0; | |
68 | ||
69 | if (memcmp (buf, gnu_sigtramp_code, GNU_SIGTRAMP_LEN) != 0) | |
70 | return 0; | |
71 | ||
72 | return pc; | |
73 | } | |
74 | ||
75 | /* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp | |
76 | routine. */ | |
77 | ||
78 | static int | |
79 | i386_gnu_sigtramp_p (struct frame_info *this_frame) | |
80 | { | |
81 | CORE_ADDR pc = get_frame_pc (this_frame); | |
82 | const char *name; | |
83 | ||
84 | find_pc_partial_function (pc, &name, NULL, NULL); | |
85 | ||
86 | /* If we have a NAME, we can check for the trampoline function */ | |
87 | if (name != NULL && strcmp (name, "trampoline") == 0) | |
88 | return 1; | |
89 | ||
90 | return i386_gnu_sigtramp_start (this_frame) != 0; | |
91 | } | |
92 | ||
93 | /* Offset to sc_i386_thread_state in sigcontext, from <bits/sigcontext.h>. */ | |
94 | #define I386_GNU_SIGCONTEXT_THREAD_STATE_OFFSET 20 | |
95 | ||
96 | /* Assuming THIS_FRAME is a GNU/Linux sigtramp routine, return the | |
97 | address of the associated sigcontext structure. */ | |
98 | ||
99 | static CORE_ADDR | |
100 | i386_gnu_sigcontext_addr (struct frame_info *this_frame) | |
101 | { | |
102 | struct gdbarch *gdbarch = get_frame_arch (this_frame); | |
103 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
104 | CORE_ADDR pc; | |
105 | CORE_ADDR sp; | |
106 | gdb_byte buf[4]; | |
107 | ||
108 | get_frame_register (this_frame, I386_ESP_REGNUM, buf); | |
109 | sp = extract_unsigned_integer (buf, 4, byte_order); | |
110 | ||
111 | pc = i386_gnu_sigtramp_start (this_frame); | |
112 | if (pc) | |
113 | { | |
114 | CORE_ADDR sigcontext_addr; | |
115 | ||
116 | /* The sigcontext structure address is passed as the third argument to | |
117 | the signal handler. */ | |
118 | read_memory (sp + 8, buf, 4); | |
119 | sigcontext_addr = extract_unsigned_integer (buf, 4, byte_order); | |
120 | return sigcontext_addr + I386_GNU_SIGCONTEXT_THREAD_STATE_OFFSET; | |
121 | } | |
122 | ||
123 | error (_("Couldn't recognize signal trampoline.")); | |
124 | return 0; | |
125 | } | |
126 | ||
127 | /* Mapping between the general-purpose registers in `struct | |
128 | sigcontext' format (starting at sc_i386_thread_state) | |
129 | and GDB's register cache layout. */ | |
130 | ||
131 | /* From <bits/sigcontext.h>. */ | |
132 | static int i386_gnu_sc_reg_offset[] = | |
133 | { | |
134 | 11 * 4, /* %eax */ | |
135 | 10 * 4, /* %ecx */ | |
136 | 9 * 4, /* %edx */ | |
137 | 8 * 4, /* %ebx */ | |
138 | 7 * 4, /* %esp */ | |
139 | 6 * 4, /* %ebp */ | |
140 | 5 * 4, /* %esi */ | |
141 | 4 * 4, /* %edi */ | |
142 | 12 * 4, /* %eip */ | |
143 | 14 * 4, /* %eflags */ | |
144 | 13 * 4, /* %cs */ | |
145 | 16 * 4, /* %ss */ | |
146 | 3 * 4, /* %ds */ | |
147 | 2 * 4, /* %es */ | |
148 | 1 * 4, /* %fs */ | |
149 | 0 * 4 /* %gs */ | |
150 | }; | |
151 | ||
ac3d87c0 UW |
152 | /* From <sys/ucontext.h>. */ |
153 | static int i386gnu_gregset_reg_offset[] = | |
154 | { | |
155 | 11 * 4, /* %eax */ | |
156 | 10 * 4, /* %ecx */ | |
157 | 9 * 4, /* %edx */ | |
158 | 8 * 4, /* %ebx */ | |
159 | 17 * 4, /* %uesp */ | |
160 | 6 * 4, /* %ebp */ | |
161 | 5 * 4, /* %esi */ | |
162 | 4 * 4, /* %edi */ | |
163 | 14 * 4, /* %eip */ | |
164 | 16 * 4, /* %efl */ | |
165 | 15 * 4, /* %cs */ | |
166 | 18 * 4, /* %ss */ | |
167 | 3 * 4, /* %ds */ | |
168 | 2 * 4, /* %es */ | |
169 | 1 * 4, /* %fs */ | |
170 | 0 * 4, /* %gs */ | |
171 | }; | |
172 | ||
e0ca2bb9 MK |
173 | static void |
174 | i386gnu_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
175 | { | |
176 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
177 | ||
178 | /* GNU uses ELF. */ | |
179 | i386_elf_init_abi (info, gdbarch); | |
180 | ||
8d005789 UW |
181 | set_solib_svr4_fetch_link_map_offsets |
182 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
183 | ||
ac3d87c0 UW |
184 | tdep->gregset_reg_offset = i386gnu_gregset_reg_offset; |
185 | tdep->gregset_num_regs = ARRAY_SIZE (i386gnu_gregset_reg_offset); | |
186 | tdep->sizeof_gregset = 19 * 4; | |
187 | ||
e0ca2bb9 | 188 | tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */ |
0af5e106 ST |
189 | |
190 | tdep->sigtramp_p = i386_gnu_sigtramp_p; | |
191 | tdep->sigcontext_addr = i386_gnu_sigcontext_addr; | |
192 | tdep->sc_reg_offset = i386_gnu_sc_reg_offset; | |
193 | tdep->sc_num_regs = ARRAY_SIZE (i386_gnu_sc_reg_offset); | |
e0ca2bb9 MK |
194 | } |
195 | ||
6c265988 | 196 | void _initialize_i386gnu_tdep (); |
e0ca2bb9 | 197 | void |
6c265988 | 198 | _initialize_i386gnu_tdep () |
e0ca2bb9 | 199 | { |
05816f70 | 200 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_HURD, i386gnu_init_abi); |
e0ca2bb9 | 201 | } |