1 /* Target-dependent code for FreeBSD/i386.
2
3 Copyright (C) 2003-2024 Free Software Foundation, 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 3 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, see <http://www.gnu.org/licenses/>. */
19
20 #include "gdbcore.h"
21 #include "osabi.h"
22 #include "regcache.h"
23 #include "regset.h"
24 #include "trad-frame.h"
25 #include "tramp-frame.h"
26 #include "i386-fbsd-tdep.h"
27
28 #include "i386-tdep.h"
29 #include "i387-tdep.h"
30 #include "fbsd-tdep.h"
31 #include "solib-svr4.h"
32 #include "inferior.h"
33
34 /* The general-purpose regset consists of 19 32-bit slots. */
35 #define I386_FBSD_SIZEOF_GREGSET (19 * 4)
36
37 /* The segment base register set consists of 2 32-bit registers. */
38 #define I386_FBSD_SIZEOF_SEGBASES_REGSET (2 * 4)
39
40 /* Register maps. */
41
42 static const struct regcache_map_entry i386_fbsd_gregmap[] =
43 {
44 { 1, I386_FS_REGNUM, 4 },
45 { 1, I386_ES_REGNUM, 4 },
46 { 1, I386_DS_REGNUM, 4 },
47 { 1, I386_EDI_REGNUM, 0 },
48 { 1, I386_ESI_REGNUM, 0 },
49 { 1, I386_EBP_REGNUM, 0 },
50 { 1, REGCACHE_MAP_SKIP, 4 }, /* isp */
51 { 1, I386_EBX_REGNUM, 0 },
52 { 1, I386_EDX_REGNUM, 0 },
53 { 1, I386_ECX_REGNUM, 0 },
54 { 1, I386_EAX_REGNUM, 0 },
55 { 1, REGCACHE_MAP_SKIP, 4 }, /* trapno */
56 { 1, REGCACHE_MAP_SKIP, 4 }, /* err */
57 { 1, I386_EIP_REGNUM, 0 },
58 { 1, I386_CS_REGNUM, 4 },
59 { 1, I386_EFLAGS_REGNUM, 0 },
60 { 1, I386_ESP_REGNUM, 0 },
61 { 1, I386_SS_REGNUM, 4 },
62 { 1, I386_GS_REGNUM, 4 },
63 { 0 }
64 };
65
66 static const struct regcache_map_entry i386_fbsd_segbases_regmap[] =
67 {
68 { 1, I386_FSBASE_REGNUM, 0 },
69 { 1, I386_GSBASE_REGNUM, 0 },
70 { 0 }
71 };
72
73 /* This layout including fsbase and gsbase was adopted in FreeBSD
74 8.0. */
75
76 static const struct regcache_map_entry i386_fbsd_mcregmap[] =
77 {
78 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_onstack */
79 { 1, I386_GS_REGNUM, 4 },
80 { 1, I386_FS_REGNUM, 4 },
81 { 1, I386_ES_REGNUM, 4 },
82 { 1, I386_DS_REGNUM, 4 },
83 { 1, I386_EDI_REGNUM, 0 },
84 { 1, I386_ESI_REGNUM, 0 },
85 { 1, I386_EBP_REGNUM, 0 },
86 { 1, REGCACHE_MAP_SKIP, 4 }, /* isp */
87 { 1, I386_EBX_REGNUM, 0 },
88 { 1, I386_EDX_REGNUM, 0 },
89 { 1, I386_ECX_REGNUM, 0 },
90 { 1, I386_EAX_REGNUM, 0 },
91 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_trapno */
92 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_err */
93 { 1, I386_EIP_REGNUM, 0 },
94 { 1, I386_CS_REGNUM, 4 },
95 { 1, I386_EFLAGS_REGNUM, 0 },
96 { 1, I386_ESP_REGNUM, 0 },
97 { 1, I386_SS_REGNUM, 4 },
98 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_len */
99 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_fpformat */
100 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_ownedfp */
101 { 1, REGCACHE_MAP_SKIP, 4 }, /* mc_flags */
102 { 128, REGCACHE_MAP_SKIP, 4 },/* mc_fpstate */
103 { 1, I386_FSBASE_REGNUM, 0 },
104 { 1, I386_GSBASE_REGNUM, 0 },
105 { 0 }
106 };
107
108 /* Register set definitions. */
109
110 const struct regset i386_fbsd_gregset =
111 {
112 i386_fbsd_gregmap, regcache_supply_regset, regcache_collect_regset
113 };
114
115 const struct regset i386_fbsd_segbases_regset =
116 {
117 i386_fbsd_segbases_regmap, regcache_supply_regset, regcache_collect_regset
118 };
119
120 /* Support for signal handlers. */
121
122 /* In a signal frame, esp points to a 'struct sigframe' which is
123 defined as:
124
125 struct sigframe {
126 register_t sf_signum;
127 register_t sf_siginfo;
128 register_t sf_ucontext;
129 register_t sf_addr;
130 union {
131 __siginfohandler_t *sf_action;
132 __sighandler_t *sf_handler;
133 } sf_ahu;
134 ucontext_t sf_uc;
135 ...
136 }
137
138 ucontext_t is defined as:
139
140 struct __ucontext {
141 sigset_t uc_sigmask;
142 mcontext_t uc_mcontext;
143 ...
144 };
145
146 The mcontext_t contains the general purpose register set as well
147 as the floating point or XSAVE state. */
148
149 /* NB: There is a 12 byte padding hole between sf_ahu and sf_uc. */
150 #define I386_SIGFRAME_UCONTEXT_OFFSET 32
151 #define I386_UCONTEXT_MCONTEXT_OFFSET 16
152 #define I386_SIZEOF_MCONTEXT_T 640
153
154 /* Implement the "init" method of struct tramp_frame. */
155
156 static void
i386_fbsd_sigframe_init(const struct tramp_frame * self,const frame_info_ptr & this_frame,struct trad_frame_cache * this_cache,CORE_ADDR func)157 i386_fbsd_sigframe_init (const struct tramp_frame *self,
158 const frame_info_ptr &this_frame,
159 struct trad_frame_cache *this_cache,
160 CORE_ADDR func)
161 {
162 CORE_ADDR sp = get_frame_register_unsigned (this_frame, I386_ESP_REGNUM);
163 CORE_ADDR mcontext_addr
164 = (sp
165 + I386_SIGFRAME_UCONTEXT_OFFSET
166 + I386_UCONTEXT_MCONTEXT_OFFSET);
167
168 trad_frame_set_reg_regmap (this_cache, i386_fbsd_mcregmap, mcontext_addr,
169 I386_SIZEOF_MCONTEXT_T);
170
171 /* Don't bother with floating point or XSAVE state for now. The
172 current helper routines for parsing FXSAVE and XSAVE state only
173 work with regcaches. This could perhaps create a temporary
174 regcache, collect the register values from mc_fpstate and
175 mc_xfpustate, and then set register values in the trad_frame. */
176
177 trad_frame_set_id (this_cache, frame_id_build (sp, func));
178 }
179
180 static const struct tramp_frame i386_fbsd_sigframe =
181 {
182 SIGTRAMP_FRAME,
183 1,
184 {
185 {0x8d, ULONGEST_MAX}, /* lea SIGF_UC(%esp),%eax */
186 {0x44, ULONGEST_MAX},
187 {0x24, ULONGEST_MAX},
188 {0x20, ULONGEST_MAX},
189 {0x50, ULONGEST_MAX}, /* pushl %eax */
190 {0xf7, ULONGEST_MAX}, /* testl $PSL_VM,UC_EFLAGS(%eax) */
191 {0x40, ULONGEST_MAX},
192 {0x54, ULONGEST_MAX},
193 {0x00, ULONGEST_MAX},
194 {0x00, ULONGEST_MAX},
195 {0x02, ULONGEST_MAX},
196 {0x00, ULONGEST_MAX},
197 {0x75, ULONGEST_MAX}, /* jne +3 */
198 {0x03, ULONGEST_MAX},
199 {0x8e, ULONGEST_MAX}, /* mov UC_GS(%eax),%gs */
200 {0x68, ULONGEST_MAX},
201 {0x14, ULONGEST_MAX},
202 {0xb8, ULONGEST_MAX}, /* movl $SYS_sigreturn,%eax */
203 {0xa1, ULONGEST_MAX},
204 {0x01, ULONGEST_MAX},
205 {0x00, ULONGEST_MAX},
206 {0x00, ULONGEST_MAX},
207 {0x50, ULONGEST_MAX}, /* pushl %eax */
208 {0xcd, ULONGEST_MAX}, /* int $0x80 */
209 {0x80, ULONGEST_MAX},
210 {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
211 },
212 i386_fbsd_sigframe_init
213 };
214
215 /* FreeBSD/i386 binaries running under an amd64 kernel use a different
216 trampoline. This trampoline differs from the i386 kernel trampoline
217 in that it omits a middle section that conditionally restores
218 %gs. */
219
220 static const struct tramp_frame i386_fbsd64_sigframe =
221 {
222 SIGTRAMP_FRAME,
223 1,
224 {
225 {0x8d, ULONGEST_MAX}, /* lea SIGF_UC(%esp),%eax */
226 {0x44, ULONGEST_MAX},
227 {0x24, ULONGEST_MAX},
228 {0x20, ULONGEST_MAX},
229 {0x50, ULONGEST_MAX}, /* pushl %eax */
230 {0xb8, ULONGEST_MAX}, /* movl $SYS_sigreturn,%eax */
231 {0xa1, ULONGEST_MAX},
232 {0x01, ULONGEST_MAX},
233 {0x00, ULONGEST_MAX},
234 {0x00, ULONGEST_MAX},
235 {0x50, ULONGEST_MAX}, /* pushl %eax */
236 {0xcd, ULONGEST_MAX}, /* int $0x80 */
237 {0x80, ULONGEST_MAX},
238 {TRAMP_SENTINEL_INSN, ULONGEST_MAX}
239 },
240 i386_fbsd_sigframe_init
241 };
242
243 /* See i386-fbsd-tdep.h. */
244
245 uint64_t
i386_fbsd_core_read_xsave_info(bfd * abfd,x86_xsave_layout & layout)246 i386_fbsd_core_read_xsave_info (bfd *abfd, x86_xsave_layout &layout)
247 {
248 asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate");
249 if (xstate == nullptr)
250 return 0;
251
252 /* Check extended state size. */
253 size_t size = bfd_section_size (xstate);
254 if (size < X86_XSTATE_AVX_SIZE)
255 return 0;
256
257 char contents[8];
258 if (! bfd_get_section_contents (abfd, xstate, contents,
259 I386_FBSD_XSAVE_XCR0_OFFSET, 8))
260 {
261 warning (_("Couldn't read `xcr0' bytes from "
262 "`.reg-xstate' section in core file."));
263 return 0;
264 }
265
266 uint64_t xcr0 = bfd_get_64 (abfd, contents);
267
268 if (!i387_guess_xsave_layout (xcr0, size, layout))
269 return 0;
270
271 return xcr0;
272 }
273
274 /* See i386-fbsd-tdep.h. */
275
276 bool
i386_fbsd_core_read_x86_xsave_layout(struct gdbarch * gdbarch,x86_xsave_layout & layout)277 i386_fbsd_core_read_x86_xsave_layout (struct gdbarch *gdbarch,
278 x86_xsave_layout &layout)
279 {
280 return i386_fbsd_core_read_xsave_info (current_program_space->core_bfd (),
281 layout) != 0;
282 }
283
284 /* Implement the core_read_description gdbarch method. */
285
286 static const struct target_desc *
i386fbsd_core_read_description(struct gdbarch * gdbarch,struct target_ops * target,bfd * abfd)287 i386fbsd_core_read_description (struct gdbarch *gdbarch,
288 struct target_ops *target,
289 bfd *abfd)
290 {
291 x86_xsave_layout layout;
292 uint64_t xcr0 = i386_fbsd_core_read_xsave_info (abfd, layout);
293 if (xcr0 == 0)
294 xcr0 = X86_XSTATE_X87_MASK;
295 return i386_target_description (xcr0, true);
296 }
297
298 /* Similar to i386_supply_fpregset, but use XSAVE extended state. */
299
300 static void
i386fbsd_supply_xstateregset(const struct regset * regset,struct regcache * regcache,int regnum,const void * xstateregs,size_t len)301 i386fbsd_supply_xstateregset (const struct regset *regset,
302 struct regcache *regcache, int regnum,
303 const void *xstateregs, size_t len)
304 {
305 i387_supply_xsave (regcache, regnum, xstateregs);
306 }
307
308 /* Similar to i386_collect_fpregset, but use XSAVE extended state. */
309
310 static void
i386fbsd_collect_xstateregset(const struct regset * regset,const struct regcache * regcache,int regnum,void * xstateregs,size_t len)311 i386fbsd_collect_xstateregset (const struct regset *regset,
312 const struct regcache *regcache,
313 int regnum, void *xstateregs, size_t len)
314 {
315 i387_collect_xsave (regcache, regnum, xstateregs, 1);
316 }
317
318 /* Register set definitions. */
319
320 static const struct regset i386fbsd_xstateregset =
321 {
322 NULL,
323 i386fbsd_supply_xstateregset,
324 i386fbsd_collect_xstateregset
325 };
326
327 /* Iterate over core file register note sections. */
328
329 static void
i386fbsd_iterate_over_regset_sections(struct gdbarch * gdbarch,iterate_over_regset_sections_cb * cb,void * cb_data,const struct regcache * regcache)330 i386fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
331 iterate_over_regset_sections_cb *cb,
332 void *cb_data,
333 const struct regcache *regcache)
334 {
335 i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
336
337 cb (".reg", I386_FBSD_SIZEOF_GREGSET, I386_FBSD_SIZEOF_GREGSET,
338 &i386_fbsd_gregset, NULL, cb_data);
339 cb (".reg2", tdep->sizeof_fpregset, tdep->sizeof_fpregset, &i386_fpregset,
340 NULL, cb_data);
341 cb (".reg-x86-segbases", I386_FBSD_SIZEOF_SEGBASES_REGSET,
342 I386_FBSD_SIZEOF_SEGBASES_REGSET, &i386_fbsd_segbases_regset,
343 "segment bases", cb_data);
344
345 if (tdep->xsave_layout.sizeof_xsave != 0)
346 cb (".reg-xstate", tdep->xsave_layout.sizeof_xsave,
347 tdep->xsave_layout.sizeof_xsave, &i386fbsd_xstateregset,
348 "XSAVE extended state", cb_data);
349 }
350
351 /* Implement the get_thread_local_address gdbarch method. */
352
353 static CORE_ADDR
i386fbsd_get_thread_local_address(struct gdbarch * gdbarch,ptid_t ptid,CORE_ADDR lm_addr,CORE_ADDR offset)354 i386fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
355 CORE_ADDR lm_addr, CORE_ADDR offset)
356 {
357 regcache *regcache
358 = get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
359
360 target_fetch_registers (regcache, I386_GSBASE_REGNUM);
361
362 ULONGEST gsbase;
363 if (regcache->cooked_read (I386_GSBASE_REGNUM, &gsbase) != REG_VALID)
364 error (_("Unable to fetch %%gsbase"));
365
366 CORE_ADDR dtv_addr = gsbase + gdbarch_ptr_bit (gdbarch) / 8;
367 return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
368 }
369
370 static void
i386fbsd_init_abi(struct gdbarch_info info,struct gdbarch * gdbarch)371 i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
372 {
373 i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
374
375 /* Generic FreeBSD support. */
376 fbsd_init_abi (info, gdbarch);
377
378 /* Obviously FreeBSD is BSD-based. */
379 i386bsd_init_abi (info, gdbarch);
380
381 /* FreeBSD reserves some space for its FPU emulator in
382 `struct fpreg'. */
383 tdep->sizeof_fpregset = 176;
384
385 /* FreeBSD uses -freg-struct-return by default. */
386 tdep->struct_return = reg_struct_return;
387
388 tramp_frame_prepend_unwinder (gdbarch, &i386_fbsd_sigframe);
389 tramp_frame_prepend_unwinder (gdbarch, &i386_fbsd64_sigframe);
390
391 i386_elf_init_abi (info, gdbarch);
392
393 tdep->xsave_xcr0_offset = I386_FBSD_XSAVE_XCR0_OFFSET;
394 set_gdbarch_core_read_x86_xsave_layout
395 (gdbarch, i386_fbsd_core_read_x86_xsave_layout);
396
397 /* Iterate over core file register note sections. */
398 set_gdbarch_iterate_over_regset_sections
399 (gdbarch, i386fbsd_iterate_over_regset_sections);
400
401 set_gdbarch_core_read_description (gdbarch,
402 i386fbsd_core_read_description);
403
404 /* FreeBSD uses SVR4-style shared libraries. */
405 set_solib_svr4_fetch_link_map_offsets
406 (gdbarch, svr4_ilp32_fetch_link_map_offsets);
407
408 set_gdbarch_fetch_tls_load_module_address (gdbarch,
409 svr4_fetch_objfile_link_map);
410 set_gdbarch_get_thread_local_address (gdbarch,
411 i386fbsd_get_thread_local_address);
412 }
413
414 void _initialize_i386fbsd_tdep ();
415 void
_initialize_i386fbsd_tdep()416 _initialize_i386fbsd_tdep ()
417 {
418 gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD,
419 i386fbsd_init_abi);
420 }
421