Commit | Line | Data |
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005328e3 | 1 | /* Target-dependent code for OpenBSD/i386. |
67457012 | 2 | |
60a6eeb6 | 3 | Copyright 1988, 1989, 1991, 1992, 1994, 1996, 2000, 2001, 2002, |
a28109e0 | 4 | 2003, 2004, 2005 |
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" |
a28109e0 | 41 | #include "bsd-uthread.h" |
005328e3 | 42 | |
5d93ae8c MK |
43 | /* Support for signal handlers. */ |
44 | ||
45 | /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page | |
46 | in virtual memory. The randomness makes it somewhat tricky to | |
47 | detect it, but fortunately we can rely on the fact that the start | |
3ed85247 MK |
48 | of the sigtramp routine is page-aligned. We recognize the |
49 | trampoline by looking for the code that invokes the sigreturn | |
50 | system call. The offset where we can find that code varies from | |
51 | release to release. | |
52 | ||
53 | By the way, the mapping mentioned above is read-only, so you cannot | |
54 | place a breakpoint in the signal trampoline. */ | |
5d93ae8c MK |
55 | |
56 | /* Default page size. */ | |
57 | static const int i386obsd_page_size = 4096; | |
58 | ||
3ed85247 MK |
59 | /* Offset for sigreturn(2). */ |
60 | static const int i386obsd_sigreturn_offset[] = { | |
61 | 0x0a, /* OpenBSD 3.2 */ | |
62 | 0x14, /* OpenBSD 3.6 */ | |
63 | 0x3a, /* OpenBSD 3.8 */ | |
64 | -1 | |
65 | }; | |
66 | ||
377d9ebd | 67 | /* Return whether the frame preceding NEXT_FRAME corresponds to an |
911bc6ee | 68 | OpenBSD sigtramp routine. */ |
5d93ae8c MK |
69 | |
70 | static int | |
911bc6ee | 71 | i386obsd_sigtramp_p (struct frame_info *next_frame) |
5d93ae8c | 72 | { |
911bc6ee | 73 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
5d93ae8c | 74 | CORE_ADDR start_pc = (pc & ~(i386obsd_page_size - 1)); |
3ed85247 | 75 | /* The call sequence invoking sigreturn(2). */ |
63c0089f | 76 | const gdb_byte sigreturn[] = |
5d93ae8c MK |
77 | { |
78 | 0xb8, | |
79 | 0x67, 0x00, 0x00, 0x00, /* movl $SYS_sigreturn, %eax */ | |
80 | 0xcd, 0x80 /* int $0x80 */ | |
81 | }; | |
c822af0c | 82 | size_t buflen = sizeof sigreturn; |
3ed85247 | 83 | const int *offset; |
63c0089f MK |
84 | gdb_byte *buf; |
85 | char *name; | |
5d93ae8c | 86 | |
911bc6ee MK |
87 | /* If the function has a valid symbol name, it isn't a |
88 | trampoline. */ | |
89 | find_pc_partial_function (pc, &name, NULL, NULL); | |
90 | if (name != NULL) | |
91 | return 0; | |
92 | ||
93 | /* If the function lives in a valid section (even without a starting | |
94 | point) it isn't a trampoline. */ | |
95 | if (find_pc_section (pc) != NULL) | |
5d93ae8c MK |
96 | return 0; |
97 | ||
9c8e3411 | 98 | /* Allocate buffer. */ |
c822af0c | 99 | buf = alloca (buflen); |
9c8e3411 | 100 | |
3ed85247 MK |
101 | /* Loop over all offsets. */ |
102 | for (offset = i386obsd_sigreturn_offset; *offset != -1; offset++) | |
103 | { | |
104 | /* If we can't read the instructions, return zero. */ | |
105 | if (!safe_frame_unwind_memory (next_frame, start_pc + *offset, | |
106 | buf, buflen)) | |
107 | return 0; | |
108 | ||
109 | /* Check for sigreturn(2). */ | |
110 | if (memcmp (buf, sigreturn, buflen) == 0) | |
111 | return 1; | |
112 | } | |
9c8e3411 | 113 | |
911bc6ee | 114 | return 0; |
5d93ae8c MK |
115 | } |
116 | \f | |
117 | /* Mapping between the general-purpose registers in `struct reg' | |
118 | format and GDB's register cache layout. */ | |
119 | ||
67457012 MK |
120 | /* From <machine/reg.h>. */ |
121 | static int i386obsd_r_reg_offset[] = | |
122 | { | |
123 | 0 * 4, /* %eax */ | |
124 | 1 * 4, /* %ecx */ | |
125 | 2 * 4, /* %edx */ | |
126 | 3 * 4, /* %ebx */ | |
127 | 4 * 4, /* %esp */ | |
128 | 5 * 4, /* %ebp */ | |
129 | 6 * 4, /* %esi */ | |
130 | 7 * 4, /* %edi */ | |
131 | 8 * 4, /* %eip */ | |
132 | 9 * 4, /* %eflags */ | |
133 | 10 * 4, /* %cs */ | |
134 | 11 * 4, /* %ss */ | |
135 | 12 * 4, /* %ds */ | |
136 | 13 * 4, /* %es */ | |
137 | 14 * 4, /* %fs */ | |
138 | 15 * 4 /* %gs */ | |
139 | }; | |
005328e3 MK |
140 | |
141 | static void | |
67457012 MK |
142 | i386obsd_aout_supply_regset (const struct regset *regset, |
143 | struct regcache *regcache, int regnum, | |
144 | const void *regs, size_t len) | |
005328e3 | 145 | { |
9ea75c57 | 146 | const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch); |
3ed85247 | 147 | const gdb_byte *gregs = regs; |
67457012 MK |
148 | |
149 | gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE); | |
005328e3 | 150 | |
67457012 | 151 | i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset); |
3ed85247 | 152 | i387_supply_fsave (regcache, regnum, gregs + tdep->sizeof_gregset); |
005328e3 MK |
153 | } |
154 | ||
49cfa46f | 155 | static const struct regset * |
67457012 MK |
156 | i386obsd_aout_regset_from_core_section (struct gdbarch *gdbarch, |
157 | const char *sect_name, | |
158 | size_t sect_size) | |
005328e3 | 159 | { |
67457012 | 160 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
005328e3 | 161 | |
67457012 MK |
162 | /* OpenBSD a.out core dumps don't use seperate register sets for the |
163 | general-purpose and floating-point registers. */ | |
005328e3 | 164 | |
67457012 MK |
165 | if (strcmp (sect_name, ".reg") == 0 |
166 | && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FSAVE) | |
005328e3 | 167 | { |
67457012 | 168 | if (tdep->gregset == NULL) |
9ea75c57 MK |
169 | tdep->gregset = |
170 | regset_alloc (gdbarch, i386obsd_aout_supply_regset, NULL); | |
67457012 | 171 | return tdep->gregset; |
005328e3 MK |
172 | } |
173 | ||
67457012 | 174 | return NULL; |
005328e3 | 175 | } |
005328e3 MK |
176 | \f |
177 | ||
5d93ae8c MK |
178 | /* Sigtramp routine location for OpenBSD 3.1 and earlier releases. */ |
179 | CORE_ADDR i386obsd_sigtramp_start_addr = 0xbfbfdf20; | |
180 | CORE_ADDR i386obsd_sigtramp_end_addr = 0xbfbfdff0; | |
005328e3 MK |
181 | |
182 | /* From <machine/signal.h>. */ | |
a3386186 MK |
183 | int i386obsd_sc_reg_offset[I386_NUM_GREGS] = |
184 | { | |
185 | 10 * 4, /* %eax */ | |
186 | 9 * 4, /* %ecx */ | |
187 | 8 * 4, /* %edx */ | |
188 | 7 * 4, /* %ebx */ | |
189 | 14 * 4, /* %esp */ | |
190 | 6 * 4, /* %ebp */ | |
191 | 5 * 4, /* %esi */ | |
192 | 4 * 4, /* %edi */ | |
193 | 11 * 4, /* %eip */ | |
194 | 13 * 4, /* %eflags */ | |
195 | 12 * 4, /* %cs */ | |
196 | 15 * 4, /* %ss */ | |
197 | 3 * 4, /* %ds */ | |
198 | 2 * 4, /* %es */ | |
199 | 1 * 4, /* %fs */ | |
200 | 0 * 4 /* %gs */ | |
201 | }; | |
005328e3 | 202 | |
a28109e0 MK |
203 | /* From /usr/src/lib/libpthread/arch/i386/uthread_machdep.c. */ |
204 | static int i386obsd_uthread_reg_offset[] = | |
205 | { | |
206 | 11 * 4, /* %eax */ | |
207 | 10 * 4, /* %ecx */ | |
208 | 9 * 4, /* %edx */ | |
209 | 8 * 4, /* %ebx */ | |
210 | -1, /* %esp */ | |
211 | 6 * 4, /* %ebp */ | |
212 | 5 * 4, /* %esi */ | |
213 | 4 * 4, /* %edi */ | |
214 | 12 * 4, /* %eip */ | |
215 | -1, /* %eflags */ | |
216 | 13 * 4, /* %cs */ | |
217 | -1, /* %ss */ | |
218 | 3 * 4, /* %ds */ | |
219 | 2 * 4, /* %es */ | |
220 | 1 * 4, /* %fs */ | |
221 | 0 * 4 /* %gs */ | |
222 | }; | |
223 | ||
224 | /* Offset within the thread structure where we can find the saved | |
225 | stack pointer (%esp). */ | |
226 | #define I386OBSD_UTHREAD_ESP_OFFSET 176 | |
227 | ||
228 | static void | |
229 | i386obsd_supply_uthread (struct regcache *regcache, | |
230 | int regnum, CORE_ADDR addr) | |
231 | { | |
232 | CORE_ADDR sp_addr = addr + I386OBSD_UTHREAD_ESP_OFFSET; | |
233 | CORE_ADDR sp = 0; | |
63c0089f | 234 | gdb_byte buf[4]; |
a28109e0 MK |
235 | int i; |
236 | ||
237 | gdb_assert (regnum >= -1); | |
238 | ||
239 | if (regnum == -1 || regnum == I386_ESP_REGNUM) | |
240 | { | |
241 | int offset; | |
242 | ||
243 | /* Fetch stack pointer from thread structure. */ | |
244 | sp = read_memory_unsigned_integer (sp_addr, 4); | |
245 | ||
246 | /* Adjust the stack pointer such that it looks as if we just | |
247 | returned from _thread_machdep_switch. */ | |
248 | offset = i386obsd_uthread_reg_offset[I386_EIP_REGNUM] + 4; | |
249 | store_unsigned_integer (buf, 4, sp + offset); | |
250 | regcache_raw_supply (regcache, I386_ESP_REGNUM, buf); | |
251 | } | |
252 | ||
253 | for (i = 0; i < ARRAY_SIZE (i386obsd_uthread_reg_offset); i++) | |
254 | { | |
255 | if (i386obsd_uthread_reg_offset[i] != -1 | |
256 | && (regnum == -1 || regnum == i)) | |
257 | { | |
258 | /* Fetch stack pointer from thread structure (if we didn't | |
259 | do so already). */ | |
260 | if (sp == 0) | |
261 | sp = read_memory_unsigned_integer (sp_addr, 4); | |
262 | ||
263 | /* Read the saved register from the stack frame. */ | |
264 | read_memory (sp + i386obsd_uthread_reg_offset[i], buf, 4); | |
265 | regcache_raw_supply (regcache, i, buf); | |
266 | } | |
267 | } | |
268 | ||
269 | } | |
270 | ||
271 | static void | |
272 | i386obsd_collect_uthread (const struct regcache *regcache, | |
273 | int regnum, CORE_ADDR addr) | |
274 | { | |
275 | CORE_ADDR sp_addr = addr + I386OBSD_UTHREAD_ESP_OFFSET; | |
276 | CORE_ADDR sp = 0; | |
63c0089f | 277 | gdb_byte buf[4]; |
a28109e0 MK |
278 | int i; |
279 | ||
280 | gdb_assert (regnum >= -1); | |
281 | ||
282 | if (regnum == -1 || regnum == I386_ESP_REGNUM) | |
283 | { | |
284 | int offset; | |
285 | ||
286 | /* Calculate the stack pointer (frame pointer) that will be | |
287 | stored into the thread structure. */ | |
288 | offset = i386obsd_uthread_reg_offset[I386_EIP_REGNUM] + 4; | |
289 | regcache_raw_collect (regcache, I386_ESP_REGNUM, buf); | |
290 | sp = extract_unsigned_integer (buf, 4) - offset; | |
291 | ||
292 | /* Store the stack pointer. */ | |
293 | write_memory_unsigned_integer (sp_addr, 4, sp); | |
294 | ||
295 | /* The stack pointer was (potentially) modified. Make sure we | |
296 | build a proper stack frame. */ | |
297 | regnum = -1; | |
298 | } | |
299 | ||
300 | for (i = 0; i < ARRAY_SIZE (i386obsd_uthread_reg_offset); i++) | |
301 | { | |
302 | if (i386obsd_uthread_reg_offset[i] != -1 | |
303 | && (regnum == -1 || regnum == i)) | |
304 | { | |
305 | /* Fetch stack pointer from thread structure (if we didn't | |
306 | calculate it already). */ | |
307 | if (sp == 0) | |
308 | sp = read_memory_unsigned_integer (sp_addr, 4); | |
309 | ||
310 | /* Write the register into the stack frame. */ | |
311 | regcache_raw_collect (regcache, i, buf); | |
312 | write_memory (sp + i386obsd_uthread_reg_offset[i], buf, 4); | |
313 | } | |
314 | } | |
315 | } | |
316 | ||
005328e3 MK |
317 | static void |
318 | i386obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
319 | { | |
320 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
321 | ||
322 | /* Obviously OpenBSD is BSD-based. */ | |
323 | i386bsd_init_abi (info, gdbarch); | |
324 | ||
67457012 MK |
325 | /* OpenBSD has a different `struct reg'. */ |
326 | tdep->gregset_reg_offset = i386obsd_r_reg_offset; | |
327 | tdep->gregset_num_regs = ARRAY_SIZE (i386obsd_r_reg_offset); | |
328 | tdep->sizeof_gregset = 16 * 4; | |
329 | ||
005328e3 MK |
330 | /* OpenBSD uses -freg-struct-return by default. */ |
331 | tdep->struct_return = reg_struct_return; | |
332 | ||
333 | /* OpenBSD uses a different memory layout. */ | |
5d93ae8c MK |
334 | tdep->sigtramp_start = i386obsd_sigtramp_start_addr; |
335 | tdep->sigtramp_end = i386obsd_sigtramp_end_addr; | |
911bc6ee | 336 | tdep->sigtramp_p = i386obsd_sigtramp_p; |
005328e3 MK |
337 | |
338 | /* OpenBSD has a `struct sigcontext' that's different from the | |
f2e7c15d | 339 | original 4.3 BSD. */ |
a3386186 | 340 | tdep->sc_reg_offset = i386obsd_sc_reg_offset; |
67457012 | 341 | tdep->sc_num_regs = ARRAY_SIZE (i386obsd_sc_reg_offset); |
a28109e0 MK |
342 | |
343 | /* OpenBSD provides a user-level threads implementation. */ | |
344 | bsd_uthread_set_supply_uthread (gdbarch, i386obsd_supply_uthread); | |
345 | bsd_uthread_set_collect_uthread (gdbarch, i386obsd_collect_uthread); | |
005328e3 | 346 | } |
60a6eeb6 MK |
347 | |
348 | /* OpenBSD a.out. */ | |
349 | ||
350 | static void | |
351 | i386obsd_aout_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
352 | { | |
353 | i386obsd_init_abi (info, gdbarch); | |
354 | ||
355 | /* OpenBSD a.out has a single register set. */ | |
356 | set_gdbarch_regset_from_core_section | |
357 | (gdbarch, i386obsd_aout_regset_from_core_section); | |
358 | } | |
359 | ||
360 | /* OpenBSD ELF. */ | |
361 | ||
362 | static void | |
363 | i386obsd_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
364 | { | |
365 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
366 | ||
367 | /* It's still OpenBSD. */ | |
368 | i386obsd_init_abi (info, gdbarch); | |
369 | ||
370 | /* But ELF-based. */ | |
371 | i386_elf_init_abi (info, gdbarch); | |
372 | ||
373 | /* OpenBSD ELF uses SVR4-style shared libraries. */ | |
60a6eeb6 MK |
374 | set_solib_svr4_fetch_link_map_offsets |
375 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
376 | } | |
67457012 MK |
377 | \f |
378 | ||
379 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
380 | void _initialize_i386obsd_tdep (void); | |
005328e3 MK |
381 | |
382 | void | |
383 | _initialize_i386obsd_tdep (void) | |
384 | { | |
005328e3 MK |
385 | /* FIXME: kettenis/20021020: Since OpenBSD/i386 binaries are |
386 | indistingushable from NetBSD/i386 a.out binaries, building a GDB | |
387 | that should support both these targets will probably not work as | |
388 | expected. */ | |
389 | #define GDB_OSABI_OPENBSD_AOUT GDB_OSABI_NETBSD_AOUT | |
390 | ||
05816f70 | 391 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_AOUT, |
60a6eeb6 MK |
392 | i386obsd_aout_init_abi); |
393 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_OPENBSD_ELF, | |
394 | i386obsd_elf_init_abi); | |
005328e3 | 395 | } |