| 1 | /* Target-dependent code for FreeBSD/i386. |
| 2 | |
| 3 | Copyright (C) 2003-2020 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 "defs.h" |
| 21 | #include "arch-utils.h" |
| 22 | #include "gdbcore.h" |
| 23 | #include "osabi.h" |
| 24 | #include "regcache.h" |
| 25 | #include "regset.h" |
| 26 | #include "i386-fbsd-tdep.h" |
| 27 | #include "gdbsupport/x86-xstate.h" |
| 28 | |
| 29 | #include "i386-tdep.h" |
| 30 | #include "i387-tdep.h" |
| 31 | #include "fbsd-tdep.h" |
| 32 | #include "solib-svr4.h" |
| 33 | |
| 34 | /* Support for signal handlers. */ |
| 35 | |
| 36 | /* Return whether THIS_FRAME corresponds to a FreeBSD sigtramp |
| 37 | routine. */ |
| 38 | |
| 39 | /* FreeBSD/i386 supports three different signal trampolines, one for |
| 40 | versions before 4.0, a second for 4.x, and a third for 5.0 and |
| 41 | later. To complicate matters, FreeBSD/i386 binaries running under |
| 42 | an amd64 kernel use a different set of trampolines. These |
| 43 | trampolines differ from the i386 kernel trampolines in that they |
| 44 | omit a middle section that conditionally restores %gs. */ |
| 45 | |
| 46 | static const gdb_byte i386fbsd_sigtramp_start[] = |
| 47 | { |
| 48 | 0x8d, 0x44, 0x24, 0x20, /* lea SIGF_UC(%esp),%eax */ |
| 49 | 0x50 /* pushl %eax */ |
| 50 | }; |
| 51 | |
| 52 | static const gdb_byte i386fbsd_sigtramp_middle[] = |
| 53 | { |
| 54 | 0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00, |
| 55 | /* testl $PSL_VM,UC_EFLAGS(%eax) */ |
| 56 | 0x75, 0x03, /* jne +3 */ |
| 57 | 0x8e, 0x68, 0x14 /* mov UC_GS(%eax),%gs */ |
| 58 | }; |
| 59 | |
| 60 | static const gdb_byte i386fbsd_sigtramp_end[] = |
| 61 | { |
| 62 | 0xb8, 0xa1, 0x01, 0x00, 0x00, /* movl $SYS_sigreturn,%eax */ |
| 63 | 0x50, /* pushl %eax */ |
| 64 | 0xcd, 0x80 /* int $0x80 */ |
| 65 | }; |
| 66 | |
| 67 | static const gdb_byte i386fbsd_freebsd4_sigtramp_start[] = |
| 68 | { |
| 69 | 0x8d, 0x44, 0x24, 0x14, /* lea SIGF_UC4(%esp),%eax */ |
| 70 | 0x50 /* pushl %eax */ |
| 71 | }; |
| 72 | |
| 73 | static const gdb_byte i386fbsd_freebsd4_sigtramp_middle[] = |
| 74 | { |
| 75 | 0xf7, 0x40, 0x54, 0x00, 0x00, 0x02, 0x00, |
| 76 | /* testl $PSL_VM,UC4_EFLAGS(%eax) */ |
| 77 | 0x75, 0x03, /* jne +3 */ |
| 78 | 0x8e, 0x68, 0x14 /* mov UC4_GS(%eax),%gs */ |
| 79 | }; |
| 80 | |
| 81 | static const gdb_byte i386fbsd_freebsd4_sigtramp_end[] = |
| 82 | { |
| 83 | 0xb8, 0x58, 0x01, 0x00, 0x00, /* movl $344,%eax */ |
| 84 | 0x50, /* pushl %eax */ |
| 85 | 0xcd, 0x80 /* int $0x80 */ |
| 86 | }; |
| 87 | |
| 88 | static const gdb_byte i386fbsd_osigtramp_start[] = |
| 89 | { |
| 90 | 0x8d, 0x44, 0x24, 0x14, /* lea SIGF_SC(%esp),%eax */ |
| 91 | 0x50 /* pushl %eax */ |
| 92 | }; |
| 93 | |
| 94 | static const gdb_byte i386fbsd_osigtramp_middle[] = |
| 95 | { |
| 96 | 0xf7, 0x40, 0x18, 0x00, 0x00, 0x02, 0x00, |
| 97 | /* testl $PSL_VM,SC_PS(%eax) */ |
| 98 | 0x75, 0x03, /* jne +3 */ |
| 99 | 0x8e, 0x68, 0x44 /* mov SC_GS(%eax),%gs */ |
| 100 | }; |
| 101 | |
| 102 | static const gdb_byte i386fbsd_osigtramp_end[] = |
| 103 | { |
| 104 | 0xb8, 0x67, 0x00, 0x00, 0x00, /* movl $103,%eax */ |
| 105 | 0x50, /* pushl %eax */ |
| 106 | 0xcd, 0x80 /* int $0x80 */ |
| 107 | }; |
| 108 | |
| 109 | /* The three different trampolines are all the same size. */ |
| 110 | gdb_static_assert (sizeof i386fbsd_sigtramp_start |
| 111 | == sizeof i386fbsd_freebsd4_sigtramp_start); |
| 112 | gdb_static_assert (sizeof i386fbsd_sigtramp_start |
| 113 | == sizeof i386fbsd_osigtramp_start); |
| 114 | gdb_static_assert (sizeof i386fbsd_sigtramp_middle |
| 115 | == sizeof i386fbsd_freebsd4_sigtramp_middle); |
| 116 | gdb_static_assert (sizeof i386fbsd_sigtramp_middle |
| 117 | == sizeof i386fbsd_osigtramp_middle); |
| 118 | gdb_static_assert (sizeof i386fbsd_sigtramp_end |
| 119 | == sizeof i386fbsd_freebsd4_sigtramp_end); |
| 120 | gdb_static_assert (sizeof i386fbsd_sigtramp_end |
| 121 | == sizeof i386fbsd_osigtramp_end); |
| 122 | |
| 123 | /* We assume that the middle is the largest chunk below. */ |
| 124 | gdb_static_assert (sizeof i386fbsd_sigtramp_middle |
| 125 | > sizeof i386fbsd_sigtramp_start); |
| 126 | gdb_static_assert (sizeof i386fbsd_sigtramp_middle |
| 127 | > sizeof i386fbsd_sigtramp_end); |
| 128 | |
| 129 | static int |
| 130 | i386fbsd_sigtramp_p (struct frame_info *this_frame) |
| 131 | { |
| 132 | CORE_ADDR pc = get_frame_pc (this_frame); |
| 133 | gdb_byte buf[sizeof i386fbsd_sigtramp_middle]; |
| 134 | const gdb_byte *middle, *end; |
| 135 | |
| 136 | /* Look for a matching start. */ |
| 137 | if (!safe_frame_unwind_memory (this_frame, pc, buf, |
| 138 | sizeof i386fbsd_sigtramp_start)) |
| 139 | return 0; |
| 140 | if (memcmp (buf, i386fbsd_sigtramp_start, sizeof i386fbsd_sigtramp_start) |
| 141 | == 0) |
| 142 | { |
| 143 | middle = i386fbsd_sigtramp_middle; |
| 144 | end = i386fbsd_sigtramp_end; |
| 145 | } |
| 146 | else if (memcmp (buf, i386fbsd_freebsd4_sigtramp_start, |
| 147 | sizeof i386fbsd_freebsd4_sigtramp_start) == 0) |
| 148 | { |
| 149 | middle = i386fbsd_freebsd4_sigtramp_middle; |
| 150 | end = i386fbsd_freebsd4_sigtramp_end; |
| 151 | } |
| 152 | else if (memcmp (buf, i386fbsd_osigtramp_start, |
| 153 | sizeof i386fbsd_osigtramp_start) == 0) |
| 154 | { |
| 155 | middle = i386fbsd_osigtramp_middle; |
| 156 | end = i386fbsd_osigtramp_end; |
| 157 | } |
| 158 | else |
| 159 | return 0; |
| 160 | |
| 161 | /* Since the end is shorter than the middle, check for a matching end |
| 162 | next. */ |
| 163 | pc += sizeof i386fbsd_sigtramp_start; |
| 164 | if (!safe_frame_unwind_memory (this_frame, pc, buf, |
| 165 | sizeof i386fbsd_sigtramp_end)) |
| 166 | return 0; |
| 167 | if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) == 0) |
| 168 | return 1; |
| 169 | |
| 170 | /* If the end didn't match, check for a matching middle. */ |
| 171 | if (!safe_frame_unwind_memory (this_frame, pc, buf, |
| 172 | sizeof i386fbsd_sigtramp_middle)) |
| 173 | return 0; |
| 174 | if (memcmp (buf, middle, sizeof i386fbsd_sigtramp_middle) != 0) |
| 175 | return 0; |
| 176 | |
| 177 | /* The middle matched, check for a matching end. */ |
| 178 | pc += sizeof i386fbsd_sigtramp_middle; |
| 179 | if (!safe_frame_unwind_memory (this_frame, pc, buf, |
| 180 | sizeof i386fbsd_sigtramp_end)) |
| 181 | return 0; |
| 182 | if (memcmp (buf, end, sizeof i386fbsd_sigtramp_end) != 0) |
| 183 | return 0; |
| 184 | |
| 185 | return 1; |
| 186 | } |
| 187 | |
| 188 | /* FreeBSD 3.0-RELEASE or later. */ |
| 189 | |
| 190 | /* From <machine/reg.h>. */ |
| 191 | static int i386fbsd_r_reg_offset[] = |
| 192 | { |
| 193 | 9 * 4, 8 * 4, 7 * 4, 6 * 4, /* %eax, %ecx, %edx, %ebx */ |
| 194 | 15 * 4, 4 * 4, /* %esp, %ebp */ |
| 195 | 3 * 4, 2 * 4, /* %esi, %edi */ |
| 196 | 12 * 4, 14 * 4, /* %eip, %eflags */ |
| 197 | 13 * 4, 16 * 4, /* %cs, %ss */ |
| 198 | 1 * 4, 0 * 4, -1, -1 /* %ds, %es, %fs, %gs */ |
| 199 | }; |
| 200 | |
| 201 | /* Sigtramp routine location. */ |
| 202 | CORE_ADDR i386fbsd_sigtramp_start_addr; |
| 203 | CORE_ADDR i386fbsd_sigtramp_end_addr; |
| 204 | |
| 205 | /* From <machine/signal.h>. */ |
| 206 | int i386fbsd_sc_reg_offset[] = |
| 207 | { |
| 208 | 8 + 14 * 4, /* %eax */ |
| 209 | 8 + 13 * 4, /* %ecx */ |
| 210 | 8 + 12 * 4, /* %edx */ |
| 211 | 8 + 11 * 4, /* %ebx */ |
| 212 | 8 + 0 * 4, /* %esp */ |
| 213 | 8 + 1 * 4, /* %ebp */ |
| 214 | 8 + 10 * 4, /* %esi */ |
| 215 | 8 + 9 * 4, /* %edi */ |
| 216 | 8 + 3 * 4, /* %eip */ |
| 217 | 8 + 4 * 4, /* %eflags */ |
| 218 | 8 + 7 * 4, /* %cs */ |
| 219 | 8 + 8 * 4, /* %ss */ |
| 220 | 8 + 6 * 4, /* %ds */ |
| 221 | 8 + 5 * 4, /* %es */ |
| 222 | 8 + 15 * 4, /* %fs */ |
| 223 | 8 + 16 * 4 /* %gs */ |
| 224 | }; |
| 225 | |
| 226 | /* Get XSAVE extended state xcr0 from core dump. */ |
| 227 | |
| 228 | uint64_t |
| 229 | i386fbsd_core_read_xcr0 (bfd *abfd) |
| 230 | { |
| 231 | asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate"); |
| 232 | uint64_t xcr0; |
| 233 | |
| 234 | if (xstate) |
| 235 | { |
| 236 | size_t size = bfd_section_size (xstate); |
| 237 | |
| 238 | /* Check extended state size. */ |
| 239 | if (size < X86_XSTATE_AVX_SIZE) |
| 240 | xcr0 = X86_XSTATE_SSE_MASK; |
| 241 | else |
| 242 | { |
| 243 | char contents[8]; |
| 244 | |
| 245 | if (! bfd_get_section_contents (abfd, xstate, contents, |
| 246 | I386_FBSD_XSAVE_XCR0_OFFSET, |
| 247 | 8)) |
| 248 | { |
| 249 | warning (_("Couldn't read `xcr0' bytes from " |
| 250 | "`.reg-xstate' section in core file.")); |
| 251 | return X86_XSTATE_SSE_MASK; |
| 252 | } |
| 253 | |
| 254 | xcr0 = bfd_get_64 (abfd, contents); |
| 255 | } |
| 256 | } |
| 257 | else |
| 258 | xcr0 = X86_XSTATE_SSE_MASK; |
| 259 | |
| 260 | return xcr0; |
| 261 | } |
| 262 | |
| 263 | /* Implement the core_read_description gdbarch method. */ |
| 264 | |
| 265 | static const struct target_desc * |
| 266 | i386fbsd_core_read_description (struct gdbarch *gdbarch, |
| 267 | struct target_ops *target, |
| 268 | bfd *abfd) |
| 269 | { |
| 270 | return i386_target_description (i386fbsd_core_read_xcr0 (abfd), true); |
| 271 | } |
| 272 | |
| 273 | /* Similar to i386_supply_fpregset, but use XSAVE extended state. */ |
| 274 | |
| 275 | static void |
| 276 | i386fbsd_supply_xstateregset (const struct regset *regset, |
| 277 | struct regcache *regcache, int regnum, |
| 278 | const void *xstateregs, size_t len) |
| 279 | { |
| 280 | i387_supply_xsave (regcache, regnum, xstateregs); |
| 281 | } |
| 282 | |
| 283 | /* Similar to i386_collect_fpregset, but use XSAVE extended state. */ |
| 284 | |
| 285 | static void |
| 286 | i386fbsd_collect_xstateregset (const struct regset *regset, |
| 287 | const struct regcache *regcache, |
| 288 | int regnum, void *xstateregs, size_t len) |
| 289 | { |
| 290 | i387_collect_xsave (regcache, regnum, xstateregs, 1); |
| 291 | } |
| 292 | |
| 293 | /* Register set definitions. */ |
| 294 | |
| 295 | static const struct regset i386fbsd_xstateregset = |
| 296 | { |
| 297 | NULL, |
| 298 | i386fbsd_supply_xstateregset, |
| 299 | i386fbsd_collect_xstateregset |
| 300 | }; |
| 301 | |
| 302 | /* Iterate over core file register note sections. */ |
| 303 | |
| 304 | static void |
| 305 | i386fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch, |
| 306 | iterate_over_regset_sections_cb *cb, |
| 307 | void *cb_data, |
| 308 | const struct regcache *regcache) |
| 309 | { |
| 310 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 311 | |
| 312 | cb (".reg", tdep->sizeof_gregset, tdep->sizeof_gregset, &i386_gregset, NULL, |
| 313 | cb_data); |
| 314 | cb (".reg2", tdep->sizeof_fpregset, tdep->sizeof_fpregset, &i386_fpregset, |
| 315 | NULL, cb_data); |
| 316 | |
| 317 | if (tdep->xcr0 & X86_XSTATE_AVX) |
| 318 | cb (".reg-xstate", X86_XSTATE_SIZE (tdep->xcr0), |
| 319 | X86_XSTATE_SIZE (tdep->xcr0), &i386fbsd_xstateregset, |
| 320 | "XSAVE extended state", cb_data); |
| 321 | } |
| 322 | |
| 323 | /* Implement the get_thread_local_address gdbarch method. */ |
| 324 | |
| 325 | static CORE_ADDR |
| 326 | i386fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid, |
| 327 | CORE_ADDR lm_addr, CORE_ADDR offset) |
| 328 | { |
| 329 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 330 | struct regcache *regcache; |
| 331 | |
| 332 | if (tdep->fsbase_regnum == -1) |
| 333 | error (_("Unable to fetch %%gsbase")); |
| 334 | |
| 335 | regcache = get_thread_arch_regcache (ptid, gdbarch); |
| 336 | |
| 337 | target_fetch_registers (regcache, tdep->fsbase_regnum + 1); |
| 338 | |
| 339 | ULONGEST gsbase; |
| 340 | if (regcache->cooked_read (tdep->fsbase_regnum + 1, &gsbase) != REG_VALID) |
| 341 | error (_("Unable to fetch %%gsbase")); |
| 342 | |
| 343 | CORE_ADDR dtv_addr = gsbase + gdbarch_ptr_bit (gdbarch) / 8; |
| 344 | return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset); |
| 345 | } |
| 346 | |
| 347 | static void |
| 348 | i386fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 349 | { |
| 350 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 351 | |
| 352 | /* Obviously FreeBSD is BSD-based. */ |
| 353 | i386bsd_init_abi (info, gdbarch); |
| 354 | |
| 355 | /* FreeBSD has a different `struct reg', and reserves some space for |
| 356 | its FPU emulator in `struct fpreg'. */ |
| 357 | tdep->gregset_reg_offset = i386fbsd_r_reg_offset; |
| 358 | tdep->gregset_num_regs = ARRAY_SIZE (i386fbsd_r_reg_offset); |
| 359 | tdep->sizeof_gregset = 18 * 4; |
| 360 | tdep->sizeof_fpregset = 176; |
| 361 | |
| 362 | /* FreeBSD uses -freg-struct-return by default. */ |
| 363 | tdep->struct_return = reg_struct_return; |
| 364 | |
| 365 | tdep->sigtramp_p = i386fbsd_sigtramp_p; |
| 366 | |
| 367 | /* FreeBSD uses a different memory layout. */ |
| 368 | tdep->sigtramp_start = i386fbsd_sigtramp_start_addr; |
| 369 | tdep->sigtramp_end = i386fbsd_sigtramp_end_addr; |
| 370 | |
| 371 | /* FreeBSD has a more complete `struct sigcontext'. */ |
| 372 | tdep->sc_reg_offset = i386fbsd_sc_reg_offset; |
| 373 | tdep->sc_num_regs = ARRAY_SIZE (i386fbsd_sc_reg_offset); |
| 374 | |
| 375 | i386_elf_init_abi (info, gdbarch); |
| 376 | |
| 377 | /* FreeBSD uses SVR4-style shared libraries. */ |
| 378 | set_solib_svr4_fetch_link_map_offsets |
| 379 | (gdbarch, svr4_ilp32_fetch_link_map_offsets); |
| 380 | } |
| 381 | |
| 382 | /* FreeBSD 4.0-RELEASE or later. */ |
| 383 | |
| 384 | /* From <machine/reg.h>. */ |
| 385 | static int i386fbsd4_r_reg_offset[] = |
| 386 | { |
| 387 | 10 * 4, 9 * 4, 8 * 4, 7 * 4, /* %eax, %ecx, %edx, %ebx */ |
| 388 | 16 * 4, 5 * 4, /* %esp, %ebp */ |
| 389 | 4 * 4, 3 * 4, /* %esi, %edi */ |
| 390 | 13 * 4, 15 * 4, /* %eip, %eflags */ |
| 391 | 14 * 4, 17 * 4, /* %cs, %ss */ |
| 392 | 2 * 4, 1 * 4, 0 * 4, 18 * 4 /* %ds, %es, %fs, %gs */ |
| 393 | }; |
| 394 | |
| 395 | /* From <machine/signal.h>. */ |
| 396 | int i386fbsd4_sc_reg_offset[] = |
| 397 | { |
| 398 | 20 + 11 * 4, /* %eax */ |
| 399 | 20 + 10 * 4, /* %ecx */ |
| 400 | 20 + 9 * 4, /* %edx */ |
| 401 | 20 + 8 * 4, /* %ebx */ |
| 402 | 20 + 17 * 4, /* %esp */ |
| 403 | 20 + 6 * 4, /* %ebp */ |
| 404 | 20 + 5 * 4, /* %esi */ |
| 405 | 20 + 4 * 4, /* %edi */ |
| 406 | 20 + 14 * 4, /* %eip */ |
| 407 | 20 + 16 * 4, /* %eflags */ |
| 408 | 20 + 15 * 4, /* %cs */ |
| 409 | 20 + 18 * 4, /* %ss */ |
| 410 | 20 + 3 * 4, /* %ds */ |
| 411 | 20 + 2 * 4, /* %es */ |
| 412 | 20 + 1 * 4, /* %fs */ |
| 413 | 20 + 0 * 4 /* %gs */ |
| 414 | }; |
| 415 | |
| 416 | static void |
| 417 | i386fbsd4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 418 | { |
| 419 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 420 | |
| 421 | /* Generic FreeBSD support. */ |
| 422 | fbsd_init_abi (info, gdbarch); |
| 423 | |
| 424 | /* Inherit stuff from older releases. We assume that FreeBSD |
| 425 | 4.0-RELEASE always uses ELF. */ |
| 426 | i386fbsd_init_abi (info, gdbarch); |
| 427 | |
| 428 | /* FreeBSD 4.0 introduced a new `struct reg'. */ |
| 429 | tdep->gregset_reg_offset = i386fbsd4_r_reg_offset; |
| 430 | tdep->gregset_num_regs = ARRAY_SIZE (i386fbsd4_r_reg_offset); |
| 431 | tdep->sizeof_gregset = 19 * 4; |
| 432 | |
| 433 | /* FreeBSD 4.0 introduced a new `struct sigcontext'. */ |
| 434 | tdep->sc_reg_offset = i386fbsd4_sc_reg_offset; |
| 435 | tdep->sc_num_regs = ARRAY_SIZE (i386fbsd4_sc_reg_offset); |
| 436 | |
| 437 | tdep->xsave_xcr0_offset = I386_FBSD_XSAVE_XCR0_OFFSET; |
| 438 | |
| 439 | /* Iterate over core file register note sections. */ |
| 440 | set_gdbarch_iterate_over_regset_sections |
| 441 | (gdbarch, i386fbsd_iterate_over_regset_sections); |
| 442 | |
| 443 | set_gdbarch_core_read_description (gdbarch, |
| 444 | i386fbsd_core_read_description); |
| 445 | |
| 446 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 447 | svr4_fetch_objfile_link_map); |
| 448 | set_gdbarch_get_thread_local_address (gdbarch, |
| 449 | i386fbsd_get_thread_local_address); |
| 450 | } |
| 451 | |
| 452 | void |
| 453 | _initialize_i386fbsd_tdep (void) |
| 454 | { |
| 455 | gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_FREEBSD, |
| 456 | i386fbsd4_init_abi); |
| 457 | } |