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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" | |
911bc6ee | 26 | #include "frame.h" |
005328e3 MK |
27 | #include "gdbcore.h" |
28 | #include "regcache.h" | |
67457012 | 29 | #include "regset.h" |
911bc6ee MK |
30 | #include "symtab.h" |
31 | #include "objfiles.h" | |
4be87837 | 32 | #include "osabi.h" |
5d93ae8c | 33 | #include "target.h" |
005328e3 | 34 | |
67457012 MK |
35 | #include "gdb_assert.h" |
36 | #include "gdb_string.h" | |
37 | ||
005328e3 MK |
38 | #include "i386-tdep.h" |
39 | #include "i387-tdep.h" | |
60a6eeb6 | 40 | #include "solib-svr4.h" |
005328e3 | 41 | |
5d93ae8c MK |
42 | /* Support for signal handlers. */ |
43 | ||
44 | /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page | |
45 | in virtual memory. The randomness makes it somewhat tricky to | |
46 | detect it, but fortunately we can rely on the fact that the start | |
47 | of the sigtramp routine is page-aligned. By the way, the mapping | |
48 | is read-only, so you cannot place a breakpoint in the signal | |
49 | trampoline. */ | |
50 | ||
51 | /* Default page size. */ | |
52 | static const int i386obsd_page_size = 4096; | |
53 | ||
377d9ebd | 54 | /* Return whether the frame preceding NEXT_FRAME corresponds to an |
911bc6ee | 55 | OpenBSD sigtramp routine. */ |
5d93ae8c MK |
56 | |
57 | static int | |
911bc6ee | 58 | i386obsd_sigtramp_p (struct frame_info *next_frame) |
5d93ae8c | 59 | { |
911bc6ee | 60 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
5d93ae8c MK |
61 | CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); |
62 | const char sigreturn[] = | |
63 | { | |
64 | 0xb8, | |
65 | 0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */ | |
66 | 0xcd, 0x80 /* int $0x80 */ | |
67 | }; | |
911bc6ee | 68 | char *name, *buf; |
5d93ae8c | 69 | |
911bc6ee MK |
70 | /* If the function has a valid symbol name, it isn't a |
71 | trampoline. */ | |
72 | find_pc_partial_function (pc, &name, NULL, NULL); | |
73 | if (name != NULL) | |
74 | return 0; | |
75 | ||
76 | /* If the function lives in a valid section (even without a starting | |
77 | point) it isn't a trampoline. */ | |
78 | if (find_pc_section (pc) != NULL) | |
5d93ae8c MK |
79 | return 0; |
80 | ||
9c8e3411 | 81 | /* Allocate buffer. */ |
5d93ae8c | 82 | buf = alloca (sizeof sigreturn); |
9c8e3411 MK |
83 | |
84 | /* If we can't read the instructions at START_PC, return zero. */ | |
85 | if (target_read_memory (start_pc + 0x0a, buf, sizeof sigreturn)) | |
5d93ae8c MK |
86 | return 0; |
87 | ||
88 | /* Check for sigreturn(2). */ | |
89 | if (memcmp (buf, sigreturn, sizeof sigreturn) == 0) | |
90 | return 1; | |
91 | ||
9c8e3411 MK |
92 | /* If we can't read the instructions at START_PC, return zero. */ |
93 | if (target_read_memory (start_pc + 0x14, buf, sizeof sigreturn)) | |
94 | return 0; | |
95 | ||
96 | /* Check for sigreturn(2) (again). */ | |
97 | if (memcmp (buf, sigreturn, sizeof sigreturn) == 0) | |
98 | return 1; | |
99 | ||
911bc6ee | 100 | return 0; |
5d93ae8c MK |
101 | } |
102 | \f | |
103 | /* Mapping between the general-purpose registers in `struct reg' | |
104 | format and GDB's register cache layout. */ | |
105 | ||
67457012 MK |
106 | /* From <machine/reg.h>. */ |
107 | static int i386obsd_r_reg_offset[] = | |
108 | { | |
109 | 0 * 4, /* %eax */ | |
110 | 1 * 4, /* %ecx */ | |
111 | 2 * 4, /* %edx */ | |
112 | 3 * 4, /* %ebx */ | |
113 | 4 * 4, /* %esp */ | |
114 | 5 * 4, /* %ebp */ | |
115 | 6 * 4, /* %esi */ | |
116 | 7 * 4, /* %edi */ | |
117 | 8 * 4, /* %eip */ | |
118 | 9 * 4, /* %eflags */ | |
119 | 10 * 4, /* %cs */ | |
120 | 11 * 4, /* %ss */ | |
121 | 12 * 4, /* %ds */ | |
122 | 13 * 4, /* %es */ | |
123 | 14 * 4, /* %fs */ | |
124 | 15 * 4 /* %gs */ | |
125 | }; | |
005328e3 MK |
126 | |
127 | static void | |
67457012 MK |
128 | i386obsd_aout_supply_regset (const struct regset *regset, |
129 | struct regcache *regcache, int regnum, | |
130 | const void *regs, size_t len) | |
005328e3 | 131 | { |
9ea75c57 | 132 | const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch); |
67457012 MK |
133 | |
134 | gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE); | |
005328e3 | 135 | |
67457012 MK |
136 | i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); |
137 | i387_supply_fsave (regcache, regnum, (char *) regs + tdep->sizeof_gregset); | |
005328e3 MK |
138 | } |
139 | ||
49cfa46f | 140 | static const struct regset * |
67457012 MK |
141 | i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch, |
142 | const char *sect_name, | |
143 | size_t sect_size) | |
005328e3 | 144 | { |
67457012 | 145 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
005328e3 | 146 | |
67457012 MK |
147 | /* OpenBSD a.out core dumps don't use seperate register sets for the |
148 | general-purpose and floating-point registers. */ | |
005328e3 | 149 | |
67457012 MK |
150 | if (strcmp (sect_name, ".reg") == 0 |
151 | && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE) | |
005328e3 | 152 | { |
67457012 | 153 | if (tdep->gregset == NULL) |
9ea75c57 MK |
154 | tdep->gregset = |
155 | regset_alloc (gdbarch, i386obsd_aout_supply_regset, NULL); | |
67457012 | 156 | return tdep->gregset; |
005328e3 MK |
157 | } |
158 | ||
67457012 | 159 | return NULL; |
005328e3 | 160 | } |
005328e3 MK |
161 | \f |
162 | ||
5d93ae8c MK |
163 | /* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */ |
164 | CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20; | |
165 | CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0; | |
005328e3 MK |
166 | |
167 | /* From <machine/signal.h>. */ | |
a3386186 MK |
168 | int i386obsd_sc_reg_offset[I386_NUM_GREGS] = |
169 | { | |
170 | 10 * 4, /* %eax */ | |
171 | 9 * 4, /* %ecx */ | |
172 | 8 * 4, /* %edx */ | |
173 | 7 * 4, /* %ebx */ | |
174 | 14 * 4, /* %esp */ | |
175 | 6 * 4, /* %ebp */ | |
176 | 5 * 4, /* %esi */ | |
177 | 4 * 4, /* %edi */ | |
178 | 11 * 4, /* %eip */ | |
179 | 13 * 4, /* %eflags */ | |
180 | 12 * 4, /* %cs */ | |
181 | 15 * 4, /* %ss */ | |
182 | 3 * 4, /* %ds */ | |
183 | 2 * 4, /* %es */ | |
184 | 1 * 4, /* %fs */ | |
185 | 0 * 4 /* %gs */ | |
186 | }; | |
005328e3 MK |
187 | |
188 | static void | |
189 | i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
190 | { | |
191 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
192 | ||
193 | /* Obviously OpenBSD is BSD-based. */ | |
194 | i386bsd_init_abi (info, gdbarch); | |
195 | ||
67457012 MK |
196 | /* OpenBSD has a different `struct reg'. */ |
197 | tdep->gregset_reg_offset = i386obsd_r_reg_offset; | |
198 | tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset); | |
199 | tdep->sizeof_gregset = 16 * 4; | |
200 | ||
005328e3 MK |
201 | /* OpenBSD uses -freg-struct-return by default. */ |
202 | tdep->struct_return = reg_struct_return; | |
203 | ||
204 | /* OpenBSD uses a different memory layout. */ | |
5d93ae8c MK |
205 | tdep->sigtramp_start = i386obsd_sigtramp_start_addr; |
206 | tdep->sigtramp_end = i386obsd_sigtramp_end_addr; | |
911bc6ee | 207 | tdep->sigtramp_p = i386obsd_sigtramp_p; |
005328e3 MK |
208 | |
209 | /* OpenBSD has a `struct sigcontext' that's different from the | |
f2e7c15d | 210 | original 4.3 BSD. */ |
a3386186 | 211 | tdep->sc_reg_offset = i386obsd_sc_reg_offset; |
67457012 | 212 | tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset); |
005328e3 | 213 | } |
60a6eeb6 MK |
214 | |
215 | /* OpenBSD a.out. */ | |
216 | ||
217 | static void | |
218 | i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
219 | { | |
220 | i386obsd_init_abi (info, gdbarch); | |
221 | ||
222 | /* OpenBSD a.out has a single register set. */ | |
223 | set_gdbarch_regset_from_core_section | |
224 | (gdbarch, i386obsd_aout_regset_from_core_section); | |
225 | } | |
226 | ||
227 | /* OpenBSD ELF. */ | |
228 | ||
229 | static void | |
230 | i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
231 | { | |
232 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
233 | ||
234 | /* It's still OpenBSD. */ | |
235 | i386obsd_init_abi (info, gdbarch); | |
236 | ||
237 | /* But ELF-based. */ | |
238 | i386_elf_init_abi (info, gdbarch); | |
239 | ||
240 | /* OpenBSD ELF uses SVR4-style shared libraries. */ | |
241 | set_gdbarch_in_solib_call_trampoline | |
242 | (gdbarch, generic_in_solib_call_trampoline); | |
243 | set_solib_svr4_fetch_link_map_offsets | |
244 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
245 | } | |
67457012 MK |
246 | \f |
247 | ||
248 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
249 | void _initialize_i386obsd_tdep (void); | |
005328e3 MK |
250 | |
251 | void | |
252 | _initialize_i386obsd_tdep (void) | |
253 | { | |
005328e3 MK |
254 | /* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are |
255 | indistingushable from NetBSD/i386 a.out binaries, building a GDB | |
256 | that should support both these targets will probably not work as | |
257 | expected. */ | |
258 | #define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT | |
259 | ||
05816f70 | 260 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT, |
60a6eeb6 MK |
261 | i386obsd_aout_init_abi); |
262 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF, | |
263 | i386obsd_elf_init_abi); | |
005328e3 | 264 | } |