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1 | /* Target-dependent code for OpenBSD/powerpc. | |
2 | ||
3 | Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 | |
4 | Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GDB. | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 3 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "arch-utils.h" | |
23 | #include "frame.h" | |
24 | #include "frame-unwind.h" | |
25 | #include "gdbtypes.h" | |
26 | #include "osabi.h" | |
27 | #include "regcache.h" | |
28 | #include "regset.h" | |
29 | #include "symtab.h" | |
30 | #include "trad-frame.h" | |
31 | ||
32 | #include "gdb_assert.h" | |
33 | #include "gdb_string.h" | |
34 | ||
35 | #include "ppc-tdep.h" | |
36 | #include "ppcobsd-tdep.h" | |
37 | #include "solib-svr4.h" | |
38 | ||
39 | /* Register offsets from <machine/reg.h>. */ | |
40 | struct ppc_reg_offsets ppcobsd_reg_offsets; | |
41 | struct ppc_reg_offsets ppcobsd_fpreg_offsets; | |
42 | \f | |
43 | ||
44 | /* Core file support. */ | |
45 | ||
46 | /* Supply register REGNUM in the general-purpose register set REGSET | |
47 | from the buffer specified by GREGS and LEN to register cache | |
48 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ | |
49 | ||
50 | void | |
51 | ppcobsd_supply_gregset (const struct regset *regset, | |
52 | struct regcache *regcache, int regnum, | |
53 | const void *gregs, size_t len) | |
54 | { | |
55 | ppc_supply_gregset (regset, regcache, regnum, gregs, len); | |
56 | ppc_supply_fpregset (regset, regcache, regnum, gregs, len); | |
57 | } | |
58 | ||
59 | /* Collect register REGNUM in the general-purpose register set | |
60 | REGSET. from register cache REGCACHE into the buffer specified by | |
61 | GREGS and LEN. If REGNUM is -1, do this for all registers in | |
62 | REGSET. */ | |
63 | ||
64 | void | |
65 | ppcobsd_collect_gregset (const struct regset *regset, | |
66 | const struct regcache *regcache, int regnum, | |
67 | void *gregs, size_t len) | |
68 | { | |
69 | ppc_collect_gregset (regset, regcache, regnum, gregs, len); | |
70 | ppc_collect_fpregset (regset, regcache, regnum, gregs, len); | |
71 | } | |
72 | ||
73 | /* OpenBSD/powerpc register set. */ | |
74 | ||
75 | struct regset ppcobsd_gregset = | |
76 | { | |
77 | &ppcobsd_reg_offsets, | |
78 | ppcobsd_supply_gregset | |
79 | }; | |
80 | ||
81 | struct regset ppcobsd_fpregset = | |
82 | { | |
83 | &ppcobsd_fpreg_offsets, | |
84 | ppc_supply_fpregset | |
85 | }; | |
86 | ||
87 | /* Return the appropriate register set for the core section identified | |
88 | by SECT_NAME and SECT_SIZE. */ | |
89 | ||
90 | static const struct regset * | |
91 | ppcobsd_regset_from_core_section (struct gdbarch *gdbarch, | |
92 | const char *sect_name, size_t sect_size) | |
93 | { | |
94 | if (strcmp (sect_name, ".reg") == 0 && sect_size >= 412) | |
95 | return &ppcobsd_gregset; | |
96 | ||
97 | return NULL; | |
98 | } | |
99 | \f | |
100 | ||
101 | /* Signal trampolines. */ | |
102 | ||
103 | /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page | |
104 | in virtual memory. The randomness makes it somewhat tricky to | |
105 | detect it, but fortunately we can rely on the fact that the start | |
106 | of the sigtramp routine is page-aligned. We recognize the | |
107 | trampoline by looking for the code that invokes the sigreturn | |
108 | system call. The offset where we can find that code varies from | |
109 | release to release. | |
110 | ||
111 | By the way, the mapping mentioned above is read-only, so you cannot | |
112 | place a breakpoint in the signal trampoline. */ | |
113 | ||
114 | /* Default page size. */ | |
115 | static const int ppcobsd_page_size = 4096; | |
116 | ||
117 | /* Offset for sigreturn(2). */ | |
118 | static const int ppcobsd_sigreturn_offset[] = { | |
119 | 0x98, /* OpenBSD 3.8 */ | |
120 | 0x0c, /* OpenBSD 3.2 */ | |
121 | -1 | |
122 | }; | |
123 | ||
124 | static int | |
125 | ppcobsd_sigtramp_frame_sniffer (const struct frame_unwind *self, | |
126 | struct frame_info *this_frame, | |
127 | void **this_cache) | |
128 | { | |
129 | struct gdbarch *gdbarch = get_frame_arch (this_frame); | |
130 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
131 | CORE_ADDR pc = get_frame_pc (this_frame); | |
132 | CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1)); | |
133 | const int *offset; | |
134 | char *name; | |
135 | ||
136 | find_pc_partial_function (pc, &name, NULL, NULL); | |
137 | if (name) | |
138 | return 0; | |
139 | ||
140 | for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++) | |
141 | { | |
142 | gdb_byte buf[2 * PPC_INSN_SIZE]; | |
143 | unsigned long insn; | |
144 | ||
145 | if (!safe_frame_unwind_memory (this_frame, start_pc + *offset, | |
146 | buf, sizeof buf)) | |
147 | continue; | |
148 | ||
149 | /* Check for "li r0,SYS_sigreturn". */ | |
150 | insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order); | |
151 | if (insn != 0x38000067) | |
152 | continue; | |
153 | ||
154 | /* Check for "sc". */ | |
155 | insn = extract_unsigned_integer (buf + PPC_INSN_SIZE, | |
156 | PPC_INSN_SIZE, byte_order); | |
157 | if (insn != 0x44000002) | |
158 | continue; | |
159 | ||
160 | return 1; | |
161 | } | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
166 | static struct trad_frame_cache * | |
167 | ppcobsd_sigtramp_frame_cache (struct frame_info *this_frame, void **this_cache) | |
168 | { | |
169 | struct gdbarch *gdbarch = get_frame_arch (this_frame); | |
170 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); | |
171 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); | |
172 | struct trad_frame_cache *cache; | |
173 | CORE_ADDR addr, base, func; | |
174 | gdb_byte buf[PPC_INSN_SIZE]; | |
175 | unsigned long insn, sigcontext_offset; | |
176 | int i; | |
177 | ||
178 | if (*this_cache) | |
179 | return *this_cache; | |
180 | ||
181 | cache = trad_frame_cache_zalloc (this_frame); | |
182 | *this_cache = cache; | |
183 | ||
184 | func = get_frame_pc (this_frame); | |
185 | func &= ~(ppcobsd_page_size - 1); | |
186 | if (!safe_frame_unwind_memory (this_frame, func, buf, sizeof buf)) | |
187 | return cache; | |
188 | ||
189 | /* Calculate the offset where we can find `struct sigcontext'. We | |
190 | base our calculation on the amount of stack space reserved by the | |
191 | first instruction of the signal trampoline. */ | |
192 | insn = extract_unsigned_integer (buf, PPC_INSN_SIZE, byte_order); | |
193 | sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8; | |
194 | ||
195 | base = get_frame_register_unsigned (this_frame, gdbarch_sp_regnum (gdbarch)); | |
196 | addr = base + sigcontext_offset + 2 * tdep->wordsize; | |
197 | for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize) | |
198 | { | |
199 | int regnum = i + tdep->ppc_gp0_regnum; | |
200 | trad_frame_set_reg_addr (cache, regnum, addr); | |
201 | } | |
202 | trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr); | |
203 | addr += tdep->wordsize; | |
204 | trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr); | |
205 | addr += tdep->wordsize; | |
206 | trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr); | |
207 | addr += tdep->wordsize; | |
208 | trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr); | |
209 | addr += tdep->wordsize; | |
210 | trad_frame_set_reg_addr (cache, gdbarch_pc_regnum (gdbarch), addr); | |
211 | /* SRR0? */ | |
212 | addr += tdep->wordsize; | |
213 | ||
214 | /* Construct the frame ID using the function start. */ | |
215 | trad_frame_set_id (cache, frame_id_build (base, func)); | |
216 | ||
217 | return cache; | |
218 | } | |
219 | ||
220 | static void | |
221 | ppcobsd_sigtramp_frame_this_id (struct frame_info *this_frame, | |
222 | void **this_cache, struct frame_id *this_id) | |
223 | { | |
224 | struct trad_frame_cache *cache = | |
225 | ppcobsd_sigtramp_frame_cache (this_frame, this_cache); | |
226 | ||
227 | trad_frame_get_id (cache, this_id); | |
228 | } | |
229 | ||
230 | static struct value * | |
231 | ppcobsd_sigtramp_frame_prev_register (struct frame_info *this_frame, | |
232 | void **this_cache, int regnum) | |
233 | { | |
234 | struct trad_frame_cache *cache = | |
235 | ppcobsd_sigtramp_frame_cache (this_frame, this_cache); | |
236 | ||
237 | return trad_frame_get_register (cache, this_frame, regnum); | |
238 | } | |
239 | ||
240 | static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = { | |
241 | SIGTRAMP_FRAME, | |
242 | ppcobsd_sigtramp_frame_this_id, | |
243 | ppcobsd_sigtramp_frame_prev_register, | |
244 | NULL, | |
245 | ppcobsd_sigtramp_frame_sniffer | |
246 | }; | |
247 | \f | |
248 | ||
249 | static void | |
250 | ppcobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) | |
251 | { | |
252 | /* OpenBSD doesn't support the 128-bit `long double' from the psABI. */ | |
253 | set_gdbarch_long_double_bit (gdbarch, 64); | |
254 | set_gdbarch_long_double_format (gdbarch, floatformats_ieee_double); | |
255 | ||
256 | /* OpenBSD currently uses a broken GCC. */ | |
257 | set_gdbarch_return_value (gdbarch, ppc_sysv_abi_broken_return_value); | |
258 | ||
259 | /* OpenBSD uses SVR4-style shared libraries. */ | |
260 | set_solib_svr4_fetch_link_map_offsets | |
261 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); | |
262 | ||
263 | set_gdbarch_regset_from_core_section | |
264 | (gdbarch, ppcobsd_regset_from_core_section); | |
265 | ||
266 | frame_unwind_append_unwinder (gdbarch, &ppcobsd_sigtramp_frame_unwind); | |
267 | } | |
268 | \f | |
269 | ||
270 | /* OpenBSD uses uses the traditional NetBSD core file format, even for | |
271 | ports that use ELF. */ | |
272 | #define GDB_OSABI_NETBSD_CORE GDB_OSABI_OPENBSD_ELF | |
273 | ||
274 | static enum gdb_osabi | |
275 | ppcobsd_core_osabi_sniffer (bfd *abfd) | |
276 | { | |
277 | if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0) | |
278 | return GDB_OSABI_NETBSD_CORE; | |
279 | ||
280 | return GDB_OSABI_UNKNOWN; | |
281 | } | |
282 | \f | |
283 | ||
284 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
285 | void _initialize_ppcobsd_tdep (void); | |
286 | ||
287 | void | |
288 | _initialize_ppcobsd_tdep (void) | |
289 | { | |
290 | /* BFD doesn't set a flavour for NetBSD style a.out core files. */ | |
291 | gdbarch_register_osabi_sniffer (bfd_arch_powerpc, bfd_target_unknown_flavour, | |
292 | ppcobsd_core_osabi_sniffer); | |
293 | ||
294 | gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_OPENBSD_ELF, | |
295 | ppcobsd_init_abi); | |
296 | gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_OPENBSD_ELF, | |
297 | ppcobsd_init_abi); | |
298 | ||
299 | /* Avoid initializing the register offsets again if they were | |
300 | already initailized by ppcobsd-nat.c. */ | |
301 | if (ppcobsd_reg_offsets.pc_offset == 0) | |
302 | { | |
303 | /* General-purpose registers. */ | |
304 | ppcobsd_reg_offsets.r0_offset = 0; | |
305 | ppcobsd_reg_offsets.gpr_size = 4; | |
306 | ppcobsd_reg_offsets.xr_size = 4; | |
307 | ppcobsd_reg_offsets.pc_offset = 384; | |
308 | ppcobsd_reg_offsets.ps_offset = 388; | |
309 | ppcobsd_reg_offsets.cr_offset = 392; | |
310 | ppcobsd_reg_offsets.lr_offset = 396; | |
311 | ppcobsd_reg_offsets.ctr_offset = 400; | |
312 | ppcobsd_reg_offsets.xer_offset = 404; | |
313 | ppcobsd_reg_offsets.mq_offset = 408; | |
314 | ||
315 | /* Floating-point registers. */ | |
316 | ppcobsd_reg_offsets.f0_offset = 128; | |
317 | ppcobsd_reg_offsets.fpscr_offset = -1; | |
318 | ||
319 | /* AltiVec registers. */ | |
320 | ppcobsd_reg_offsets.vr0_offset = 0; | |
321 | ppcobsd_reg_offsets.vscr_offset = 512; | |
322 | ppcobsd_reg_offsets.vrsave_offset = 520; | |
323 | } | |
324 | ||
325 | if (ppcobsd_fpreg_offsets.fpscr_offset == 0) | |
326 | { | |
327 | /* Floating-point registers. */ | |
328 | ppcobsd_reg_offsets.f0_offset = 0; | |
329 | ppcobsd_reg_offsets.fpscr_offset = 256; | |
330 | ppcobsd_reg_offsets.fpscr_size = 4; | |
331 | } | |
332 | } |