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005328e3 | 1 | /* Target-dependent code for OpenBSD/i386. |
67457012 | 2 | |
60a6eeb6 MK |
3 | Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, |
4 | 2003, 2004 | |
005328e3 MK |
5 | Free Software Foundation, Inc. |
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 "arch-utils.h" | |
26 | #include "gdbcore.h" | |
27 | #include "regcache.h" | |
67457012 | 28 | #include "regset.h" |
4be87837 | 29 | #include "osabi.h" |
5d93ae8c | 30 | #include "target.h" |
005328e3 | 31 | |
67457012 MK |
32 | #include "gdb_assert.h" |
33 | #include "gdb_string.h" | |
34 | ||
005328e3 MK |
35 | #include "i386-tdep.h" |
36 | #include "i387-tdep.h" | |
60a6eeb6 | 37 | #include "solib-svr4.h" |
005328e3 | 38 | |
5d93ae8c MK |
39 | /* Support for signal handlers. */ |
40 | ||
41 | /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page | |
42 | in virtual memory. The randomness makes it somewhat tricky to | |
43 | detect it, but fortunately we can rely on the fact that the start | |
44 | of the sigtramp routine is page-aligned. By the way, the mapping | |
45 | is read-only, so you cannot place a breakpoint in the signal | |
46 | trampoline. */ | |
47 | ||
48 | /* Default page size. */ | |
49 | static const int i386obsd_page_size = 4096; | |
50 | ||
51 | /* Return whether PC is in an OpenBSD sigtramp routine. */ | |
52 | ||
53 | static int | |
54 | i386obsd_pc_in_sigtramp (CORE_ADDR pc, char *name) | |
55 | { | |
56 | CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); | |
57 | const char sigreturn[] = | |
58 | { | |
59 | 0xb8, | |
60 | 0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */ | |
61 | 0xcd, 0x80 /* int $0x80 */ | |
62 | }; | |
63 | char *buf; | |
64 | ||
65 | /* Avoid reading memory from the target if possible. If we're in a | |
66 | named function, we're certainly not in a sigtramp routine | |
67 | provided by the kernel. Take synthetic function names into | |
68 | account though. */ | |
69 | if (name && name[0] != '<') | |
70 | return 0; | |
71 | ||
72 | /* If we can't read the instructions at START_PC, return zero. */ | |
73 | buf = alloca (sizeof sigreturn); | |
74 | if (target_read_memory (start_pc + 0x14, buf, sizeof sigreturn)) | |
75 | return 0; | |
76 | ||
77 | /* Check for sigreturn(2). */ | |
78 | if (memcmp (buf, sigreturn, sizeof sigreturn) == 0) | |
79 | return 1; | |
80 | ||
81 | /* Check for a traditional BSD sigtramp routine. */ | |
82 | return i386bsd_pc_in_sigtramp (pc, name); | |
83 | } | |
84 | ||
85 | /* Return the start address of the sigtramp routine. */ | |
86 | ||
87 | static CORE_ADDR | |
88 | i386obsd_sigtramp_start (CORE_ADDR pc) | |
89 | { | |
90 | CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); | |
91 | ||
92 | if (i386bsd_pc_in_sigtramp (pc, NULL)) | |
93 | return i386bsd_sigtramp_start (pc); | |
94 | ||
95 | return start_pc; | |
96 | } | |
97 | ||
98 | /* Return the end address of the sigtramp routine. */ | |
99 | ||
100 | static CORE_ADDR | |
101 | i386obsd_sigtramp_end (CORE_ADDR pc) | |
102 | { | |
103 | CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); | |
104 | ||
105 | if (i386bsd_pc_in_sigtramp (pc, NULL)) | |
106 | return i386bsd_sigtramp_end (pc); | |
107 | ||
108 | return start_pc + 0x22; | |
109 | } | |
110 | \f | |
111 | /* Mapping between the general-purpose registers in `struct reg' | |
112 | format and GDB's register cache layout. */ | |
113 | ||
67457012 MK |
114 | /* From <machine/reg.h>. */ |
115 | static int i386obsd_r_reg_offset[] = | |
116 | { | |
117 | 0 * 4, /* %eax */ | |
118 | 1 * 4, /* %ecx */ | |
119 | 2 * 4, /* %edx */ | |
120 | 3 * 4, /* %ebx */ | |
121 | 4 * 4, /* %esp */ | |
122 | 5 * 4, /* %ebp */ | |
123 | 6 * 4, /* %esi */ | |
124 | 7 * 4, /* %edi */ | |
125 | 8 * 4, /* %eip */ | |
126 | 9 * 4, /* %eflags */ | |
127 | 10 * 4, /* %cs */ | |
128 | 11 * 4, /* %ss */ | |
129 | 12 * 4, /* %ds */ | |
130 | 13 * 4, /* %es */ | |
131 | 14 * 4, /* %fs */ | |
132 | 15 * 4 /* %gs */ | |
133 | }; | |
005328e3 MK |
134 | |
135 | static void | |
67457012 MK |
136 | i386obsd_aout_supply_regset (const struct regset *regset, |
137 | struct regcache *regcache, int regnum, | |
138 | const void *regs, size_t len) | |
005328e3 | 139 | { |
67457012 MK |
140 | const struct gdbarch_tdep *tdep = regset->descr; |
141 | ||
142 | gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE); | |
005328e3 | 143 | |
67457012 MK |
144 | i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); |
145 | i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset); | |
005328e3 MK |
146 | } |
147 | ||
49cfa46f | 148 | static const struct regset * |
67457012 MK |
149 | i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch, |
150 | const char *sect_name, | |
151 | size_t sect_size) | |
005328e3 | 152 | { |
67457012 | 153 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
005328e3 | 154 | |
67457012 MK |
155 | /* OpenBSD a.out core dumps don't use seperate register sets for the |
156 | general-purpose and floating-point registers. */ | |
005328e3 | 157 | |
67457012 MK |
158 | if (strcmp (sect_name, ".reg") == 0 |
159 | && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE) | |
005328e3 | 160 | { |
67457012 MK |
161 | if (tdep->gregset == NULL) |
162 | { | |
163 | tdep->gregset = XMALLOC (struct regset); | |
164 | tdep->gregset->descr = tdep; | |
165 | tdep->gregset->supply_regset = i386obsd_aout_supply_regset; | |
166 | } | |
167 | return tdep->gregset; | |
005328e3 MK |
168 | } |
169 | ||
67457012 | 170 | return NULL; |
005328e3 | 171 | } |
005328e3 MK |
172 | \f |
173 | ||
5d93ae8c MK |
174 | /* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */ |
175 | CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20; | |
176 | CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0; | |
005328e3 MK |
177 | |
178 | /* From <machine/signal.h>. */ | |
a3386186 MK |
179 | int i386obsd_sc_reg_offset[I386_NUM_GREGS] = |
180 | { | |
181 | 10 * 4, /* %eax */ | |
182 | 9 * 4, /* %ecx */ | |
183 | 8 * 4, /* %edx */ | |
184 | 7 * 4, /* %ebx */ | |
185 | 14 * 4, /* %esp */ | |
186 | 6 * 4, /* %ebp */ | |
187 | 5 * 4, /* %esi */ | |
188 | 4 * 4, /* %edi */ | |
189 | 11 * 4, /* %eip */ | |
190 | 13 * 4, /* %eflags */ | |
191 | 12 * 4, /* %cs */ | |
192 | 15 * 4, /* %ss */ | |
193 | 3 * 4, /* %ds */ | |
194 | 2 * 4, /* %es */ | |
195 | 1 * 4, /* %fs */ | |
196 | 0 * 4 /* %gs */ | |
197 | }; | |
005328e3 MK |
198 | |
199 | static void | |
200 | i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
201 | { | |
202 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
203 | ||
204 | /* Obviously OpenBSD is BSD-based. */ | |
205 | i386bsd_init_abi (info, gdbarch); | |
206 | ||
67457012 MK |
207 | /* OpenBSD has a different `struct reg'. */ |
208 | tdep->gregset_reg_offset = i386obsd_r_reg_offset; | |
209 | tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset); | |
210 | tdep->sizeof_gregset = 16 * 4; | |
211 | ||
005328e3 MK |
212 | /* OpenBSD uses -freg-struct-return by default. */ |
213 | tdep->struct_return = reg_struct_return; | |
214 | ||
215 | /* OpenBSD uses a different memory layout. */ | |
5d93ae8c MK |
216 | tdep->sigtramp_start = i386obsd_sigtramp_start_addr; |
217 | tdep->sigtramp_end = i386obsd_sigtramp_end_addr; | |
218 | set_gdbarch_pc_in_sigtramp (gdbarch, i386obsd_pc_in_sigtramp); | |
219 | set_gdbarch_sigtramp_start (gdbarch, i386obsd_sigtramp_start); | |
220 | set_gdbarch_sigtramp_end (gdbarch, i386obsd_sigtramp_end); | |
005328e3 MK |
221 | |
222 | /* OpenBSD has a `struct sigcontext' that's different from the | |
223 | origional 4.3 BSD. */ | |
a3386186 | 224 | tdep->sc_reg_offset = i386obsd_sc_reg_offset; |
67457012 | 225 | tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset); |
005328e3 | 226 | } |
60a6eeb6 MK |
227 | |
228 | /* OpenBSD a.out. */ | |
229 | ||
230 | static void | |
231 | i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
232 | { | |
233 | i386obsd_init_abi (info, gdbarch); | |
234 | ||
235 | /* OpenBSD a.out has a single register set. */ | |
236 | set_gdbarch_regset_from_core_section | |
237 | (gdbarch, i386obsd_aout_regset_from_core_section); | |
238 | } | |
239 | ||
240 | /* OpenBSD ELF. */ | |
241 | ||
242 | static void | |
243 | i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
244 | { | |
245 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
246 | ||
247 | /* It's still OpenBSD. */ | |
248 | i386obsd_init_abi (info, gdbarch); | |
249 | ||
250 | /* But ELF-based. */ | |
251 | i386_elf_init_abi (info, gdbarch); | |
252 | ||
253 | /* OpenBSD ELF uses SVR4-style shared libraries. */ | |
254 | set_gdbarch_in_solib_call_trampoline | |
255 | (gdbarch, generic_in_solib_call_trampoline); | |
256 | set_solib_svr4_fetch_link_map_offsets | |
257 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
258 | } | |
67457012 MK |
259 | \f |
260 | ||
261 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
262 | void _initialize_i386obsd_tdep (void); | |
005328e3 MK |
263 | |
264 | void | |
265 | _initialize_i386obsd_tdep (void) | |
266 | { | |
005328e3 MK |
267 | /* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are |
268 | indistingushable from NetBSD/i386 a.out binaries, building a GDB | |
269 | that should support both these targets will probably not work as | |
270 | expected. */ | |
271 | #define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT | |
272 | ||
05816f70 | 273 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT, |
60a6eeb6 MK |
274 | i386obsd_aout_init_abi); |
275 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF, | |
276 | i386obsd_elf_init_abi); | |
005328e3 | 277 | } |