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45888261 JT |
1 | /* Target-dependent code for MIPS systems running NetBSD. |
2 | Copyright 2002 Free Software Foundation, Inc. | |
3 | Contributed by Wasabi Systems, Inc. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
22 | #include "defs.h" | |
23 | #include "gdbcore.h" | |
24 | #include "regcache.h" | |
25 | #include "target.h" | |
26 | #include "value.h" | |
27 | #include "osabi.h" | |
28 | ||
29 | #include "mipsnbsd-tdep.h" | |
30 | ||
31 | #include "solib-svr4.h" | |
32 | ||
33 | /* Conveniently, GDB uses the same register numbering as the | |
34 | ptrace register structure used by NetBSD/mips. */ | |
35 | ||
36 | void | |
37 | mipsnbsd_supply_reg (char *regs, int regno) | |
38 | { | |
39 | int i; | |
40 | ||
41 | for (i = 0; i <= PC_REGNUM; i++) | |
42 | { | |
43 | if (regno == i || regno == -1) | |
44 | { | |
45 | if (CANNOT_FETCH_REGISTER (i)) | |
46 | supply_register (i, NULL); | |
47 | else | |
48 | supply_register (i, regs + (i * MIPS_REGSIZE)); | |
49 | } | |
50 | } | |
51 | } | |
52 | ||
53 | void | |
54 | mipsnbsd_fill_reg (char *regs, int regno) | |
55 | { | |
56 | int i; | |
57 | ||
58 | for (i = 0; i <= PC_REGNUM; i++) | |
59 | if ((regno == i || regno == -1) && ! CANNOT_STORE_REGISTER (i)) | |
60 | regcache_collect (i, regs + (i * MIPS_REGSIZE)); | |
61 | } | |
62 | ||
63 | void | |
64 | mipsnbsd_supply_fpreg (char *fpregs, int regno) | |
65 | { | |
66 | int i; | |
67 | ||
68 | for (i = FP0_REGNUM; i <= FCRIR_REGNUM; i++) | |
69 | { | |
70 | if (regno == i || regno == -1) | |
71 | { | |
72 | if (CANNOT_FETCH_REGISTER (i)) | |
73 | supply_register (i, NULL); | |
74 | else | |
75 | supply_register (i, fpregs + ((i - FP0_REGNUM) * MIPS_REGSIZE)); | |
76 | } | |
77 | } | |
78 | } | |
79 | ||
80 | void | |
81 | mipsnbsd_fill_fpreg (char *fpregs, int regno) | |
82 | { | |
83 | int i; | |
84 | ||
85 | for (i = FP0_REGNUM; i <= FCRCS_REGNUM; i++) | |
86 | if ((regno == i || regno == -1) && ! CANNOT_STORE_REGISTER (i)) | |
87 | regcache_collect (i, fpregs + ((i - FP0_REGNUM) * MIPS_REGSIZE)); | |
88 | } | |
89 | ||
90 | static void | |
91 | fetch_core_registers (char *core_reg_sect, unsigned core_reg_size, int which, | |
92 | CORE_ADDR ignore) | |
93 | { | |
94 | char *regs, *fpregs; | |
95 | ||
96 | /* We get everything from one section. */ | |
97 | if (which != 0) | |
98 | return; | |
99 | ||
100 | regs = core_reg_sect; | |
101 | fpregs = core_reg_sect + SIZEOF_STRUCT_REG; | |
102 | ||
103 | /* Integer registers. */ | |
104 | mipsnbsd_supply_reg (regs, -1); | |
105 | ||
106 | /* Floating point registers. */ | |
107 | mipsnbsd_supply_fpreg (regs, -1); | |
108 | } | |
109 | ||
110 | static void | |
111 | fetch_elfcore_registers (char *core_reg_sect, unsigned core_reg_size, int which, | |
112 | CORE_ADDR ignore) | |
113 | { | |
114 | switch (which) | |
115 | { | |
116 | case 0: /* Integer registers. */ | |
117 | if (core_reg_size != SIZEOF_STRUCT_REG) | |
118 | warning ("Wrong size register set in core file."); | |
119 | else | |
120 | mipsnbsd_supply_reg (core_reg_sect, -1); | |
121 | break; | |
122 | ||
123 | case 2: /* Floating point registers. */ | |
124 | if (core_reg_size != SIZEOF_STRUCT_FPREG) | |
125 | warning ("Wrong size register set in core file."); | |
126 | else | |
127 | mipsnbsd_supply_fpreg (core_reg_sect, -1); | |
128 | break; | |
129 | ||
130 | default: | |
131 | /* Don't know what kind of register request this is; just ignore it. */ | |
132 | break; | |
133 | } | |
134 | } | |
135 | ||
136 | static struct core_fns mipsnbsd_core_fns = | |
137 | { | |
138 | bfd_target_unknown_flavour, /* core_flavour */ | |
139 | default_check_format, /* check_format */ | |
140 | default_core_sniffer, /* core_sniffer */ | |
141 | fetch_core_registers, /* core_read_registers */ | |
142 | NULL /* next */ | |
143 | }; | |
144 | ||
145 | static struct core_fns mipsnbsd_elfcore_fns = | |
146 | { | |
147 | bfd_target_elf_flavour, /* core_flavour */ | |
148 | default_check_format, /* check_format */ | |
149 | default_core_sniffer, /* core_sniffer */ | |
150 | fetch_elfcore_registers, /* core_read_registers */ | |
151 | NULL /* next */ | |
152 | }; | |
153 | ||
154 | /* Under NetBSD/mips, signal handler invocations can be identified by the | |
155 | designated code sequence that is used to return from a signal handler. | |
156 | In particular, the return address of a signal handler points to the | |
157 | following code sequence: | |
158 | ||
159 | addu a0, sp, 16 | |
160 | li v0, 295 # __sigreturn14 | |
161 | syscall | |
162 | ||
163 | Each instruction has a unique encoding, so we simply attempt to match | |
164 | the instruction the PC is pointing to with any of the above instructions. | |
165 | If there is a hit, we know the offset to the start of the designated | |
166 | sequence and can then check whether we really are executing in the | |
167 | signal trampoline. If not, -1 is returned, otherwise the offset from the | |
168 | start of the return sequence is returned. */ | |
169 | ||
170 | #define RETCODE_NWORDS 3 | |
171 | #define RETCODE_SIZE (RETCODE_NWORDS * 4) | |
172 | ||
173 | static const unsigned char sigtramp_retcode_mipsel[RETCODE_SIZE] = | |
174 | { | |
175 | 0x10, 0x00, 0xa4, 0x27, /* addu a0, sp, 16 */ | |
176 | 0x27, 0x01, 0x02, 0x24, /* li v0, 295 */ | |
177 | 0x0c, 0x00, 0x00, 0x00, /* syscall */ | |
178 | }; | |
179 | ||
180 | static const unsigned char sigtramp_retcode_mipseb[RETCODE_SIZE] = | |
181 | { | |
182 | 0x27, 0xa4, 0x00, 0x10, /* addu a0, sp, 16 */ | |
183 | 0x24, 0x02, 0x01, 0x27, /* li v0, 295 */ | |
184 | 0x00, 0x00, 0x00, 0x0c, /* syscall */ | |
185 | }; | |
186 | ||
187 | static LONGEST | |
188 | mipsnbsd_sigtramp_offset (CORE_ADDR pc) | |
189 | { | |
190 | const char *retcode = TARGET_BYTE_ORDER == BFD_ENDIAN_BIG | |
191 | ? sigtramp_retcode_mipseb : sigtramp_retcode_mipsel; | |
192 | unsigned char ret[RETCODE_SIZE], w[4]; | |
193 | LONGEST off; | |
194 | int i; | |
195 | ||
196 | if (read_memory_nobpt (pc, (char *) w, sizeof (w)) != 0) | |
197 | return -1; | |
198 | ||
199 | for (i = 0; i < RETCODE_NWORDS; i++) | |
200 | { | |
201 | if (memcmp (w, retcode + (i * 4), 4) == 0) | |
202 | break; | |
203 | } | |
204 | if (i == RETCODE_NWORDS) | |
205 | return -1; | |
206 | ||
207 | off = i * 4; | |
208 | pc -= off; | |
209 | ||
210 | if (read_memory_nobpt (pc, (char *) ret, sizeof (ret)) != 0) | |
211 | return -1; | |
212 | ||
213 | if (memcmp (ret, retcode, RETCODE_SIZE) == 0) | |
214 | return off; | |
215 | ||
216 | return -1; | |
217 | } | |
218 | ||
219 | static int | |
220 | mipsnbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name) | |
221 | { | |
222 | return (mipsnbsd_sigtramp_offset (pc) >= 0); | |
223 | } | |
224 | ||
225 | /* Figure out where the longjmp will land. We expect that we have | |
226 | just entered longjmp and haven't yet setup the stack frame, so | |
227 | the args are still in the argument regs. A0_REGNUM points at the | |
228 | jmp_buf structure from which we extract the PC that we will land | |
229 | at. The PC is copied into *pc. This routine returns true on | |
230 | success. */ | |
231 | ||
232 | #define NBSD_MIPS_JB_PC (2 * 4) | |
233 | #define NBSD_MIPS_JB_ELEMENT_SIZE MIPS_REGSIZE | |
234 | #define NBSD_MIPS_JB_OFFSET (NBSD_MIPS_JB_PC * \ | |
235 | NBSD_MIPS_JB_ELEMENT_SIZE) | |
236 | ||
237 | static int | |
238 | mipsnbsd_get_longjmp_target (CORE_ADDR *pc) | |
239 | { | |
240 | CORE_ADDR jb_addr; | |
241 | char *buf; | |
242 | ||
243 | buf = alloca (NBSD_MIPS_JB_ELEMENT_SIZE); | |
244 | ||
245 | jb_addr = read_register (A0_REGNUM); | |
246 | ||
247 | if (target_read_memory (jb_addr + NBSD_MIPS_JB_OFFSET, buf, | |
248 | NBSD_MIPS_JB_ELEMENT_SIZE)) | |
249 | return 0; | |
250 | ||
251 | *pc = extract_address (buf, NBSD_MIPS_JB_ELEMENT_SIZE); | |
252 | ||
253 | return 1; | |
254 | } | |
255 | ||
256 | static int | |
257 | mipsnbsd_cannot_fetch_register (int regno) | |
258 | { | |
259 | return (regno >= FP_REGNUM | |
260 | || regno == ZERO_REGNUM | |
261 | || regno == FCRIR_REGNUM); | |
262 | } | |
263 | ||
264 | static int | |
265 | mipsnbsd_cannot_store_register (int regno) | |
266 | { | |
267 | return (regno >= FP_REGNUM | |
268 | || regno == ZERO_REGNUM | |
269 | || regno == FCRIR_REGNUM); | |
270 | } | |
271 | ||
272 | /* NetBSD/mips uses a slightly different link_map structure from the | |
273 | other NetBSD platforms. */ | |
274 | static struct link_map_offsets * | |
275 | mipsnbsd_ilp32_solib_svr4_fetch_link_map_offsets (void) | |
276 | { | |
277 | static struct link_map_offsets lmo; | |
278 | static struct link_map_offsets *lmp = NULL; | |
279 | ||
280 | if (lmp == NULL) | |
281 | { | |
282 | lmp = &lmo; | |
283 | ||
284 | lmo.r_debug_size = 16; | |
285 | ||
286 | lmo.r_map_offset = 4; | |
287 | lmo.r_map_size = 4; | |
288 | ||
289 | lmo.link_map_size = 24; | |
290 | ||
291 | lmo.l_addr_offset = 0; | |
292 | lmo.l_addr_size = 4; | |
293 | ||
294 | lmo.l_name_offset = 8; | |
295 | lmo.l_name_size = 4; | |
296 | ||
297 | lmo.l_next_offset = 16; | |
298 | lmo.l_next_size = 4; | |
299 | ||
300 | lmo.l_prev_offset = 20; | |
301 | lmo.l_prev_size = 4; | |
302 | } | |
303 | ||
304 | return lmp; | |
305 | } | |
306 | ||
307 | static struct link_map_offsets * | |
308 | mipsnbsd_lp64_solib_svr4_fetch_link_map_offsets (void) | |
309 | { | |
310 | static struct link_map_offsets lmo; | |
311 | static struct link_map_offsets *lmp = NULL; | |
312 | ||
313 | if (lmp == NULL) | |
314 | { | |
315 | lmp = &lmo; | |
316 | ||
317 | lmo.r_debug_size = 32; | |
318 | ||
319 | lmo.r_map_offset = 8; | |
320 | lmo.r_map_size = 8; | |
321 | ||
322 | lmo.link_map_size = 48; | |
323 | ||
324 | lmo.l_addr_offset = 0; | |
325 | lmo.l_addr_size = 8; | |
326 | ||
327 | lmo.l_name_offset = 16; | |
328 | lmo.l_name_size = 8; | |
329 | ||
330 | lmo.l_next_offset = 32; | |
331 | lmo.l_next_size = 8; | |
332 | ||
333 | lmo.l_prev_offset = 40; | |
334 | lmo.l_prev_size = 8; | |
335 | } | |
336 | ||
337 | return lmp; | |
338 | } | |
339 | ||
340 | static void | |
341 | mipsnbsd_init_abi (struct gdbarch_info info, | |
342 | struct gdbarch *gdbarch) | |
343 | { | |
344 | set_gdbarch_pc_in_sigtramp (gdbarch, mipsnbsd_pc_in_sigtramp); | |
345 | ||
346 | set_gdbarch_get_longjmp_target (gdbarch, mipsnbsd_get_longjmp_target); | |
347 | ||
348 | set_gdbarch_cannot_fetch_register (gdbarch, mipsnbsd_cannot_fetch_register); | |
349 | set_gdbarch_cannot_store_register (gdbarch, mipsnbsd_cannot_store_register); | |
350 | ||
351 | set_gdbarch_software_single_step (gdbarch, mips_software_single_step); | |
352 | ||
353 | set_solib_svr4_fetch_link_map_offsets (gdbarch, | |
354 | gdbarch_ptr_bit (gdbarch) == 32 ? | |
355 | mipsnbsd_ilp32_solib_svr4_fetch_link_map_offsets : | |
356 | mipsnbsd_lp64_solib_svr4_fetch_link_map_offsets); | |
357 | } | |
358 | ||
359 | void | |
360 | _initialize_mipsnbsd_tdep (void) | |
361 | { | |
362 | gdbarch_register_osabi (bfd_arch_mips, GDB_OSABI_NETBSD_ELF, | |
363 | mipsnbsd_init_abi); | |
364 | ||
365 | add_core_fns (&mipsnbsd_core_fns); | |
366 | add_core_fns (&mipsnbsd_elfcore_fns); | |
367 | } |