1 /* Target-dependent code for GNU/Linux i386. 2 3 Copyright (C) 2000-2015 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 "gdbcore.h" 22 #include "frame.h" 23 #include "value.h" 24 #include "regcache.h" 25 #include "regset.h" 26 #include "inferior.h" 27 #include "osabi.h" 28 #include "reggroups.h" 29 #include "dwarf2-frame.h" 30 #include "i386-tdep.h" 31 #include "i386-linux-tdep.h" 32 #include "linux-tdep.h" 33 #include "glibc-tdep.h" 34 #include "solib-svr4.h" 35 #include "symtab.h" 36 #include "arch-utils.h" 37 #include "xml-syscall.h" 38 39 #include "i387-tdep.h" 40 #include "x86-xstate.h" 41 42 /* The syscall's XML filename for i386. */ 43 #define XML_SYSCALL_FILENAME_I386 "syscalls/i386-linux.xml" 44 45 #include "record-full.h" 46 #include "linux-record.h" 47 #include <stdint.h> 48 49 #include "features/i386/i386-linux.c" 50 #include "features/i386/i386-mmx-linux.c" 51 #include "features/i386/i386-mpx-linux.c" 52 #include "features/i386/i386-avx-linux.c" 53 #include "features/i386/i386-avx512-linux.c" 54 55 /* Return non-zero, when the register is in the corresponding register 56 group. Put the LINUX_ORIG_EAX register in the system group. */ 57 static int 58 i386_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum, 59 struct reggroup *group) 60 { 61 if (regnum == I386_LINUX_ORIG_EAX_REGNUM) 62 return (group == system_reggroup 63 || group == save_reggroup 64 || group == restore_reggroup); 65 return i386_register_reggroup_p (gdbarch, regnum, group); 66 } 67 68 69 /* Recognizing signal handler frames. */ 70 71 /* GNU/Linux has two flavors of signals. Normal signal handlers, and 72 "realtime" (RT) signals. The RT signals can provide additional 73 information to the signal handler if the SA_SIGINFO flag is set 74 when establishing a signal handler using `sigaction'. It is not 75 unlikely that future versions of GNU/Linux will support SA_SIGINFO 76 for normal signals too. */ 77 78 /* When the i386 Linux kernel calls a signal handler and the 79 SA_RESTORER flag isn't set, the return address points to a bit of 80 code on the stack. This function returns whether the PC appears to 81 be within this bit of code. 82 83 The instruction sequence for normal signals is 84 pop %eax 85 mov $0x77, %eax 86 int $0x80 87 or 0x58 0xb8 0x77 0x00 0x00 0x00 0xcd 0x80. 88 89 Checking for the code sequence should be somewhat reliable, because 90 the effect is to call the system call sigreturn. This is unlikely 91 to occur anywhere other than in a signal trampoline. 92 93 It kind of sucks that we have to read memory from the process in 94 order to identify a signal trampoline, but there doesn't seem to be 95 any other way. Therefore we only do the memory reads if no 96 function name could be identified, which should be the case since 97 the code is on the stack. 98 99 Detection of signal trampolines for handlers that set the 100 SA_RESTORER flag is in general not possible. Unfortunately this is 101 what the GNU C Library has been doing for quite some time now. 102 However, as of version 2.1.2, the GNU C Library uses signal 103 trampolines (named __restore and __restore_rt) that are identical 104 to the ones used by the kernel. Therefore, these trampolines are 105 supported too. */ 106 107 #define LINUX_SIGTRAMP_INSN0 0x58 /* pop %eax */ 108 #define LINUX_SIGTRAMP_OFFSET0 0 109 #define LINUX_SIGTRAMP_INSN1 0xb8 /* mov $NNNN, %eax */ 110 #define LINUX_SIGTRAMP_OFFSET1 1 111 #define LINUX_SIGTRAMP_INSN2 0xcd /* int */ 112 #define LINUX_SIGTRAMP_OFFSET2 6 113 114 static const gdb_byte linux_sigtramp_code[] = 115 { 116 LINUX_SIGTRAMP_INSN0, /* pop %eax */ 117 LINUX_SIGTRAMP_INSN1, 0x77, 0x00, 0x00, 0x00, /* mov $0x77, %eax */ 118 LINUX_SIGTRAMP_INSN2, 0x80 /* int $0x80 */ 119 }; 120 121 #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code) 122 123 /* If THIS_FRAME is a sigtramp routine, return the address of the 124 start of the routine. Otherwise, return 0. */ 125 126 static CORE_ADDR 127 i386_linux_sigtramp_start (struct frame_info *this_frame) 128 { 129 CORE_ADDR pc = get_frame_pc (this_frame); 130 gdb_byte buf[LINUX_SIGTRAMP_LEN]; 131 132 /* We only recognize a signal trampoline if PC is at the start of 133 one of the three instructions. We optimize for finding the PC at 134 the start, as will be the case when the trampoline is not the 135 first frame on the stack. We assume that in the case where the 136 PC is not at the start of the instruction sequence, there will be 137 a few trailing readable bytes on the stack. */ 138 139 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN)) 140 return 0; 141 142 if (buf[0] != LINUX_SIGTRAMP_INSN0) 143 { 144 int adjust; 145 146 switch (buf[0]) 147 { 148 case LINUX_SIGTRAMP_INSN1: 149 adjust = LINUX_SIGTRAMP_OFFSET1; 150 break; 151 case LINUX_SIGTRAMP_INSN2: 152 adjust = LINUX_SIGTRAMP_OFFSET2; 153 break; 154 default: 155 return 0; 156 } 157 158 pc -= adjust; 159 160 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_SIGTRAMP_LEN)) 161 return 0; 162 } 163 164 if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0) 165 return 0; 166 167 return pc; 168 } 169 170 /* This function does the same for RT signals. Here the instruction 171 sequence is 172 mov $0xad, %eax 173 int $0x80 174 or 0xb8 0xad 0x00 0x00 0x00 0xcd 0x80. 175 176 The effect is to call the system call rt_sigreturn. */ 177 178 #define LINUX_RT_SIGTRAMP_INSN0 0xb8 /* mov $NNNN, %eax */ 179 #define LINUX_RT_SIGTRAMP_OFFSET0 0 180 #define LINUX_RT_SIGTRAMP_INSN1 0xcd /* int */ 181 #define LINUX_RT_SIGTRAMP_OFFSET1 5 182 183 static const gdb_byte linux_rt_sigtramp_code[] = 184 { 185 LINUX_RT_SIGTRAMP_INSN0, 0xad, 0x00, 0x00, 0x00, /* mov $0xad, %eax */ 186 LINUX_RT_SIGTRAMP_INSN1, 0x80 /* int $0x80 */ 187 }; 188 189 #define LINUX_RT_SIGTRAMP_LEN (sizeof linux_rt_sigtramp_code) 190 191 /* If THIS_FRAME is an RT sigtramp routine, return the address of the 192 start of the routine. Otherwise, return 0. */ 193 194 static CORE_ADDR 195 i386_linux_rt_sigtramp_start (struct frame_info *this_frame) 196 { 197 CORE_ADDR pc = get_frame_pc (this_frame); 198 gdb_byte buf[LINUX_RT_SIGTRAMP_LEN]; 199 200 /* We only recognize a signal trampoline if PC is at the start of 201 one of the two instructions. We optimize for finding the PC at 202 the start, as will be the case when the trampoline is not the 203 first frame on the stack. We assume that in the case where the 204 PC is not at the start of the instruction sequence, there will be 205 a few trailing readable bytes on the stack. */ 206 207 if (!safe_frame_unwind_memory (this_frame, pc, buf, LINUX_RT_SIGTRAMP_LEN)) 208 return 0; 209 210 if (buf[0] != LINUX_RT_SIGTRAMP_INSN0) 211 { 212 if (buf[0] != LINUX_RT_SIGTRAMP_INSN1) 213 return 0; 214 215 pc -= LINUX_RT_SIGTRAMP_OFFSET1; 216 217 if (!safe_frame_unwind_memory (this_frame, pc, buf, 218 LINUX_RT_SIGTRAMP_LEN)) 219 return 0; 220 } 221 222 if (memcmp (buf, linux_rt_sigtramp_code, LINUX_RT_SIGTRAMP_LEN) != 0) 223 return 0; 224 225 return pc; 226 } 227 228 /* Return whether THIS_FRAME corresponds to a GNU/Linux sigtramp 229 routine. */ 230 231 static int 232 i386_linux_sigtramp_p (struct frame_info *this_frame) 233 { 234 CORE_ADDR pc = get_frame_pc (this_frame); 235 const char *name; 236 237 find_pc_partial_function (pc, &name, NULL, NULL); 238 239 /* If we have NAME, we can optimize the search. The trampolines are 240 named __restore and __restore_rt. However, they aren't dynamically 241 exported from the shared C library, so the trampoline may appear to 242 be part of the preceding function. This should always be sigaction, 243 __sigaction, or __libc_sigaction (all aliases to the same function). */ 244 if (name == NULL || strstr (name, "sigaction") != NULL) 245 return (i386_linux_sigtramp_start (this_frame) != 0 246 || i386_linux_rt_sigtramp_start (this_frame) != 0); 247 248 return (strcmp ("__restore", name) == 0 249 || strcmp ("__restore_rt", name) == 0); 250 } 251 252 /* Return one if the PC of THIS_FRAME is in a signal trampoline which 253 may have DWARF-2 CFI. */ 254 255 static int 256 i386_linux_dwarf_signal_frame_p (struct gdbarch *gdbarch, 257 struct frame_info *this_frame) 258 { 259 CORE_ADDR pc = get_frame_pc (this_frame); 260 const char *name; 261 262 find_pc_partial_function (pc, &name, NULL, NULL); 263 264 /* If a vsyscall DSO is in use, the signal trampolines may have these 265 names. */ 266 if (name && (strcmp (name, "__kernel_sigreturn") == 0 267 || strcmp (name, "__kernel_rt_sigreturn") == 0)) 268 return 1; 269 270 return 0; 271 } 272 273 /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */ 274 #define I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 20 275 276 /* Assuming THIS_FRAME is a GNU/Linux sigtramp routine, return the 277 address of the associated sigcontext structure. */ 278 279 static CORE_ADDR 280 i386_linux_sigcontext_addr (struct frame_info *this_frame) 281 { 282 struct gdbarch *gdbarch = get_frame_arch (this_frame); 283 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 284 CORE_ADDR pc; 285 CORE_ADDR sp; 286 gdb_byte buf[4]; 287 288 get_frame_register (this_frame, I386_ESP_REGNUM, buf); 289 sp = extract_unsigned_integer (buf, 4, byte_order); 290 291 pc = i386_linux_sigtramp_start (this_frame); 292 if (pc) 293 { 294 /* The sigcontext structure lives on the stack, right after 295 the signum argument. We determine the address of the 296 sigcontext structure by looking at the frame's stack 297 pointer. Keep in mind that the first instruction of the 298 sigtramp code is "pop %eax". If the PC is after this 299 instruction, adjust the returned value accordingly. */ 300 if (pc == get_frame_pc (this_frame)) 301 return sp + 4; 302 return sp; 303 } 304 305 pc = i386_linux_rt_sigtramp_start (this_frame); 306 if (pc) 307 { 308 CORE_ADDR ucontext_addr; 309 310 /* The sigcontext structure is part of the user context. A 311 pointer to the user context is passed as the third argument 312 to the signal handler. */ 313 read_memory (sp + 8, buf, 4); 314 ucontext_addr = extract_unsigned_integer (buf, 4, byte_order); 315 return ucontext_addr + I386_LINUX_UCONTEXT_SIGCONTEXT_OFFSET; 316 } 317 318 error (_("Couldn't recognize signal trampoline.")); 319 return 0; 320 } 321 322 /* Set the program counter for process PTID to PC. */ 323 324 static void 325 i386_linux_write_pc (struct regcache *regcache, CORE_ADDR pc) 326 { 327 regcache_cooked_write_unsigned (regcache, I386_EIP_REGNUM, pc); 328 329 /* We must be careful with modifying the program counter. If we 330 just interrupted a system call, the kernel might try to restart 331 it when we resume the inferior. On restarting the system call, 332 the kernel will try backing up the program counter even though it 333 no longer points at the system call. This typically results in a 334 SIGSEGV or SIGILL. We can prevent this by writing `-1' in the 335 "orig_eax" pseudo-register. 336 337 Note that "orig_eax" is saved when setting up a dummy call frame. 338 This means that it is properly restored when that frame is 339 popped, and that the interrupted system call will be restarted 340 when we resume the inferior on return from a function call from 341 within GDB. In all other cases the system call will not be 342 restarted. */ 343 regcache_cooked_write_unsigned (regcache, I386_LINUX_ORIG_EAX_REGNUM, -1); 344 } 345 346 /* Record all registers but IP register for process-record. */ 347 348 static int 349 i386_all_but_ip_registers_record (struct regcache *regcache) 350 { 351 if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM)) 352 return -1; 353 if (record_full_arch_list_add_reg (regcache, I386_ECX_REGNUM)) 354 return -1; 355 if (record_full_arch_list_add_reg (regcache, I386_EDX_REGNUM)) 356 return -1; 357 if (record_full_arch_list_add_reg (regcache, I386_EBX_REGNUM)) 358 return -1; 359 if (record_full_arch_list_add_reg (regcache, I386_ESP_REGNUM)) 360 return -1; 361 if (record_full_arch_list_add_reg (regcache, I386_EBP_REGNUM)) 362 return -1; 363 if (record_full_arch_list_add_reg (regcache, I386_ESI_REGNUM)) 364 return -1; 365 if (record_full_arch_list_add_reg (regcache, I386_EDI_REGNUM)) 366 return -1; 367 if (record_full_arch_list_add_reg (regcache, I386_EFLAGS_REGNUM)) 368 return -1; 369 370 return 0; 371 } 372 373 /* i386_canonicalize_syscall maps from the native i386 Linux set 374 of syscall ids into a canonical set of syscall ids used by 375 process record (a mostly trivial mapping, since the canonical 376 set was originally taken from the i386 set). */ 377 378 static enum gdb_syscall 379 i386_canonicalize_syscall (int syscall) 380 { 381 enum { i386_syscall_max = 499 }; 382 383 if (syscall <= i386_syscall_max) 384 return syscall; 385 else 386 return -1; 387 } 388 389 /* Parse the arguments of current system call instruction and record 390 the values of the registers and memory that will be changed into 391 "record_arch_list". This instruction is "int 0x80" (Linux 392 Kernel2.4) or "sysenter" (Linux Kernel 2.6). 393 394 Return -1 if something wrong. */ 395 396 static struct linux_record_tdep i386_linux_record_tdep; 397 398 static int 399 i386_linux_intx80_sysenter_syscall_record (struct regcache *regcache) 400 { 401 int ret; 402 LONGEST syscall_native; 403 enum gdb_syscall syscall_gdb; 404 405 regcache_raw_read_signed (regcache, I386_EAX_REGNUM, &syscall_native); 406 407 syscall_gdb = i386_canonicalize_syscall (syscall_native); 408 409 if (syscall_gdb < 0) 410 { 411 printf_unfiltered (_("Process record and replay target doesn't " 412 "support syscall number %s\n"), 413 plongest (syscall_native)); 414 return -1; 415 } 416 417 if (syscall_gdb == gdb_sys_sigreturn 418 || syscall_gdb == gdb_sys_rt_sigreturn) 419 { 420 if (i386_all_but_ip_registers_record (regcache)) 421 return -1; 422 return 0; 423 } 424 425 ret = record_linux_system_call (syscall_gdb, regcache, 426 &i386_linux_record_tdep); 427 if (ret) 428 return ret; 429 430 /* Record the return value of the system call. */ 431 if (record_full_arch_list_add_reg (regcache, I386_EAX_REGNUM)) 432 return -1; 433 434 return 0; 435 } 436 437 #define I386_LINUX_xstate 270 438 #define I386_LINUX_frame_size 732 439 440 static int 441 i386_linux_record_signal (struct gdbarch *gdbarch, 442 struct regcache *regcache, 443 enum gdb_signal signal) 444 { 445 ULONGEST esp; 446 447 if (i386_all_but_ip_registers_record (regcache)) 448 return -1; 449 450 if (record_full_arch_list_add_reg (regcache, I386_EIP_REGNUM)) 451 return -1; 452 453 /* Record the change in the stack. */ 454 regcache_raw_read_unsigned (regcache, I386_ESP_REGNUM, &esp); 455 /* This is for xstate. 456 sp -= sizeof (struct _fpstate); */ 457 esp -= I386_LINUX_xstate; 458 /* This is for frame_size. 459 sp -= sizeof (struct rt_sigframe); */ 460 esp -= I386_LINUX_frame_size; 461 if (record_full_arch_list_add_mem (esp, 462 I386_LINUX_xstate + I386_LINUX_frame_size)) 463 return -1; 464 465 if (record_full_arch_list_add_end ()) 466 return -1; 467 468 return 0; 469 } 470 471 472 /* Core of the implementation for gdbarch get_syscall_number. Get pending 473 syscall number from REGCACHE. If there is no pending syscall -1 will be 474 returned. Pending syscall means ptrace has stepped into the syscall but 475 another ptrace call will step out. PC is right after the int $0x80 476 / syscall / sysenter instruction in both cases, PC does not change during 477 the second ptrace step. */ 478 479 static LONGEST 480 i386_linux_get_syscall_number_from_regcache (struct regcache *regcache) 481 { 482 struct gdbarch *gdbarch = get_regcache_arch (regcache); 483 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 484 /* The content of a register. */ 485 gdb_byte buf[4]; 486 /* The result. */ 487 LONGEST ret; 488 489 /* Getting the system call number from the register. 490 When dealing with x86 architecture, this information 491 is stored at %eax register. */ 492 regcache_cooked_read (regcache, I386_LINUX_ORIG_EAX_REGNUM, buf); 493 494 ret = extract_signed_integer (buf, 4, byte_order); 495 496 return ret; 497 } 498 499 /* Wrapper for i386_linux_get_syscall_number_from_regcache to make it 500 compatible with gdbarch get_syscall_number method prototype. */ 501 502 static LONGEST 503 i386_linux_get_syscall_number (struct gdbarch *gdbarch, 504 ptid_t ptid) 505 { 506 struct regcache *regcache = get_thread_regcache (ptid); 507 508 return i386_linux_get_syscall_number_from_regcache (regcache); 509 } 510 511 /* The register sets used in GNU/Linux ELF core-dumps are identical to 512 the register sets in `struct user' that are used for a.out 513 core-dumps. These are also used by ptrace(2). The corresponding 514 types are `elf_gregset_t' for the general-purpose registers (with 515 `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' 516 for the floating-point registers. 517 518 Those types used to be available under the names `gregset_t' and 519 `fpregset_t' too, and GDB used those names in the past. But those 520 names are now used for the register sets used in the `mcontext_t' 521 type, which have a different size and layout. */ 522 523 /* Mapping between the general-purpose registers in `struct user' 524 format and GDB's register cache layout. */ 525 526 /* From <sys/reg.h>. */ 527 int i386_linux_gregset_reg_offset[] = 528 { 529 6 * 4, /* %eax */ 530 1 * 4, /* %ecx */ 531 2 * 4, /* %edx */ 532 0 * 4, /* %ebx */ 533 15 * 4, /* %esp */ 534 5 * 4, /* %ebp */ 535 3 * 4, /* %esi */ 536 4 * 4, /* %edi */ 537 12 * 4, /* %eip */ 538 14 * 4, /* %eflags */ 539 13 * 4, /* %cs */ 540 16 * 4, /* %ss */ 541 7 * 4, /* %ds */ 542 8 * 4, /* %es */ 543 9 * 4, /* %fs */ 544 10 * 4, /* %gs */ 545 -1, -1, -1, -1, -1, -1, -1, -1, 546 -1, -1, -1, -1, -1, -1, -1, -1, 547 -1, -1, -1, -1, -1, -1, -1, -1, 548 -1, 549 -1, -1, -1, -1, -1, -1, -1, -1, 550 -1, -1, -1, -1, /* MPX registers BND0 ... BND3. */ 551 -1, -1, /* MPX registers BNDCFGU, BNDSTATUS. */ 552 -1, -1, -1, -1, -1, -1, -1, -1, /* k0 ... k7 (AVX512) */ 553 -1, -1, -1, -1, -1, -1, -1, -1, /* zmm0 ... zmm7 (AVX512) */ 554 11 * 4, /* "orig_eax" */ 555 }; 556 557 /* Mapping between the general-purpose registers in `struct 558 sigcontext' format and GDB's register cache layout. */ 559 560 /* From <asm/sigcontext.h>. */ 561 static int i386_linux_sc_reg_offset[] = 562 { 563 11 * 4, /* %eax */ 564 10 * 4, /* %ecx */ 565 9 * 4, /* %edx */ 566 8 * 4, /* %ebx */ 567 7 * 4, /* %esp */ 568 6 * 4, /* %ebp */ 569 5 * 4, /* %esi */ 570 4 * 4, /* %edi */ 571 14 * 4, /* %eip */ 572 16 * 4, /* %eflags */ 573 15 * 4, /* %cs */ 574 18 * 4, /* %ss */ 575 3 * 4, /* %ds */ 576 2 * 4, /* %es */ 577 1 * 4, /* %fs */ 578 0 * 4 /* %gs */ 579 }; 580 581 /* Get XSAVE extended state xcr0 from core dump. */ 582 583 uint64_t 584 i386_linux_core_read_xcr0 (bfd *abfd) 585 { 586 asection *xstate = bfd_get_section_by_name (abfd, ".reg-xstate"); 587 uint64_t xcr0; 588 589 if (xstate) 590 { 591 size_t size = bfd_section_size (abfd, xstate); 592 593 /* Check extended state size. */ 594 if (size < X86_XSTATE_AVX_SIZE) 595 xcr0 = X86_XSTATE_SSE_MASK; 596 else 597 { 598 char contents[8]; 599 600 if (! bfd_get_section_contents (abfd, xstate, contents, 601 I386_LINUX_XSAVE_XCR0_OFFSET, 602 8)) 603 { 604 warning (_("Couldn't read `xcr0' bytes from " 605 "`.reg-xstate' section in core file.")); 606 return 0; 607 } 608 609 xcr0 = bfd_get_64 (abfd, contents); 610 } 611 } 612 else 613 xcr0 = 0; 614 615 return xcr0; 616 } 617 618 /* Get Linux/x86 target description from core dump. */ 619 620 static const struct target_desc * 621 i386_linux_core_read_description (struct gdbarch *gdbarch, 622 struct target_ops *target, 623 bfd *abfd) 624 { 625 /* Linux/i386. */ 626 uint64_t xcr0 = i386_linux_core_read_xcr0 (abfd); 627 628 switch ((xcr0 & X86_XSTATE_ALL_MASK)) 629 { 630 case X86_XSTATE_MPX_AVX512_MASK: 631 case X86_XSTATE_AVX512_MASK: 632 return tdesc_i386_avx512_linux; 633 case X86_XSTATE_MPX_MASK: 634 return tdesc_i386_mpx_linux; 635 case X86_XSTATE_AVX_MASK: 636 return tdesc_i386_avx_linux; 637 case X86_XSTATE_SSE_MASK: 638 return tdesc_i386_linux; 639 case X86_XSTATE_X87_MASK: 640 return tdesc_i386_mmx_linux; 641 default: 642 break; 643 } 644 645 if (bfd_get_section_by_name (abfd, ".reg-xfp") != NULL) 646 return tdesc_i386_linux; 647 else 648 return tdesc_i386_mmx_linux; 649 } 650 651 /* Similar to i386_supply_fpregset, but use XSAVE extended state. */ 652 653 static void 654 i386_linux_supply_xstateregset (const struct regset *regset, 655 struct regcache *regcache, int regnum, 656 const void *xstateregs, size_t len) 657 { 658 i387_supply_xsave (regcache, regnum, xstateregs); 659 } 660 661 /* Similar to i386_collect_fpregset, but use XSAVE extended state. */ 662 663 static void 664 i386_linux_collect_xstateregset (const struct regset *regset, 665 const struct regcache *regcache, 666 int regnum, void *xstateregs, size_t len) 667 { 668 i387_collect_xsave (regcache, regnum, xstateregs, 1); 669 } 670 671 /* Register set definitions. */ 672 673 static const struct regset i386_linux_xstateregset = 674 { 675 NULL, 676 i386_linux_supply_xstateregset, 677 i386_linux_collect_xstateregset 678 }; 679 680 /* Iterate over core file register note sections. */ 681 682 static void 683 i386_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 684 iterate_over_regset_sections_cb *cb, 685 void *cb_data, 686 const struct regcache *regcache) 687 { 688 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 689 690 cb (".reg", 68, &i386_gregset, NULL, cb_data); 691 692 if (tdep->xcr0 & X86_XSTATE_AVX) 693 /* Use max size for writing, accept any size when reading. */ 694 cb (".reg-xstate", regcache ? X86_XSTATE_MAX_SIZE : 0, 695 &i386_linux_xstateregset, "XSAVE extended state", cb_data); 696 else if (tdep->xcr0 & X86_XSTATE_SSE) 697 cb (".reg-xfp", 512, &i386_fpregset, "extended floating-point", 698 cb_data); 699 else 700 cb (".reg2", 108, &i386_fpregset, NULL, cb_data); 701 } 702 703 /* Linux kernel shows PC value after the 'int $0x80' instruction even if 704 inferior is still inside the syscall. On next PTRACE_SINGLESTEP it will 705 finish the syscall but PC will not change. 706 707 Some vDSOs contain 'int $0x80; ret' and during stepping out of the syscall 708 i386_displaced_step_fixup would keep PC at the displaced pad location. 709 As PC is pointing to the 'ret' instruction before the step 710 i386_displaced_step_fixup would expect inferior has just executed that 'ret' 711 and PC should not be adjusted. In reality it finished syscall instead and 712 PC should get relocated back to its vDSO address. Hide the 'ret' 713 instruction by 'nop' so that i386_displaced_step_fixup is not confused. 714 715 It is not fully correct as the bytes in struct displaced_step_closure will 716 not match the inferior code. But we would need some new flag in 717 displaced_step_closure otherwise to keep the state that syscall is finishing 718 for the later i386_displaced_step_fixup execution as the syscall execution 719 is already no longer detectable there. The new flag field would mean 720 i386-linux-tdep.c needs to wrap all the displacement methods of i386-tdep.c 721 which does not seem worth it. The same effect is achieved by patching that 722 'nop' instruction there instead. */ 723 724 static struct displaced_step_closure * 725 i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch, 726 CORE_ADDR from, CORE_ADDR to, 727 struct regcache *regs) 728 { 729 struct displaced_step_closure *closure; 730 731 closure = i386_displaced_step_copy_insn (gdbarch, from, to, regs); 732 733 if (i386_linux_get_syscall_number_from_regcache (regs) != -1) 734 { 735 /* Since we use simple_displaced_step_copy_insn, our closure is a 736 copy of the instruction. */ 737 gdb_byte *insn = (gdb_byte *) closure; 738 739 /* Fake nop. */ 740 insn[0] = 0x90; 741 } 742 743 return closure; 744 } 745 746 static void 747 i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 748 { 749 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 750 const struct target_desc *tdesc = info.target_desc; 751 struct tdesc_arch_data *tdesc_data = (void *) info.tdep_info; 752 const struct tdesc_feature *feature; 753 int valid_p; 754 755 gdb_assert (tdesc_data); 756 757 linux_init_abi (info, gdbarch); 758 759 /* GNU/Linux uses ELF. */ 760 i386_elf_init_abi (info, gdbarch); 761 762 /* Reserve a number for orig_eax. */ 763 set_gdbarch_num_regs (gdbarch, I386_LINUX_NUM_REGS); 764 765 if (! tdesc_has_registers (tdesc)) 766 tdesc = tdesc_i386_linux; 767 tdep->tdesc = tdesc; 768 769 feature = tdesc_find_feature (tdesc, "org.gnu.gdb.i386.linux"); 770 if (feature == NULL) 771 return; 772 773 valid_p = tdesc_numbered_register (feature, tdesc_data, 774 I386_LINUX_ORIG_EAX_REGNUM, 775 "orig_eax"); 776 if (!valid_p) 777 return; 778 779 /* Add the %orig_eax register used for syscall restarting. */ 780 set_gdbarch_write_pc (gdbarch, i386_linux_write_pc); 781 782 tdep->register_reggroup_p = i386_linux_register_reggroup_p; 783 784 tdep->gregset_reg_offset = i386_linux_gregset_reg_offset; 785 tdep->gregset_num_regs = ARRAY_SIZE (i386_linux_gregset_reg_offset); 786 tdep->sizeof_gregset = 17 * 4; 787 788 tdep->jb_pc_offset = 20; /* From <bits/setjmp.h>. */ 789 790 tdep->sigtramp_p = i386_linux_sigtramp_p; 791 tdep->sigcontext_addr = i386_linux_sigcontext_addr; 792 tdep->sc_reg_offset = i386_linux_sc_reg_offset; 793 tdep->sc_num_regs = ARRAY_SIZE (i386_linux_sc_reg_offset); 794 795 tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET; 796 797 set_gdbarch_process_record (gdbarch, i386_process_record); 798 set_gdbarch_process_record_signal (gdbarch, i386_linux_record_signal); 799 800 /* Initialize the i386_linux_record_tdep. */ 801 /* These values are the size of the type that will be used in a system 802 call. They are obtained from Linux Kernel source. */ 803 i386_linux_record_tdep.size_pointer 804 = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; 805 i386_linux_record_tdep.size__old_kernel_stat = 32; 806 i386_linux_record_tdep.size_tms = 16; 807 i386_linux_record_tdep.size_loff_t = 8; 808 i386_linux_record_tdep.size_flock = 16; 809 i386_linux_record_tdep.size_oldold_utsname = 45; 810 i386_linux_record_tdep.size_ustat = 20; 811 i386_linux_record_tdep.size_old_sigaction = 140; 812 i386_linux_record_tdep.size_old_sigset_t = 128; 813 i386_linux_record_tdep.size_rlimit = 8; 814 i386_linux_record_tdep.size_rusage = 72; 815 i386_linux_record_tdep.size_timeval = 8; 816 i386_linux_record_tdep.size_timezone = 8; 817 i386_linux_record_tdep.size_old_gid_t = 2; 818 i386_linux_record_tdep.size_old_uid_t = 2; 819 i386_linux_record_tdep.size_fd_set = 128; 820 i386_linux_record_tdep.size_dirent = 268; 821 i386_linux_record_tdep.size_dirent64 = 276; 822 i386_linux_record_tdep.size_statfs = 64; 823 i386_linux_record_tdep.size_statfs64 = 84; 824 i386_linux_record_tdep.size_sockaddr = 16; 825 i386_linux_record_tdep.size_int 826 = gdbarch_int_bit (gdbarch) / TARGET_CHAR_BIT; 827 i386_linux_record_tdep.size_long 828 = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT; 829 i386_linux_record_tdep.size_ulong 830 = gdbarch_long_bit (gdbarch) / TARGET_CHAR_BIT; 831 i386_linux_record_tdep.size_msghdr = 28; 832 i386_linux_record_tdep.size_itimerval = 16; 833 i386_linux_record_tdep.size_stat = 88; 834 i386_linux_record_tdep.size_old_utsname = 325; 835 i386_linux_record_tdep.size_sysinfo = 64; 836 i386_linux_record_tdep.size_msqid_ds = 88; 837 i386_linux_record_tdep.size_shmid_ds = 84; 838 i386_linux_record_tdep.size_new_utsname = 390; 839 i386_linux_record_tdep.size_timex = 128; 840 i386_linux_record_tdep.size_mem_dqinfo = 24; 841 i386_linux_record_tdep.size_if_dqblk = 68; 842 i386_linux_record_tdep.size_fs_quota_stat = 68; 843 i386_linux_record_tdep.size_timespec = 8; 844 i386_linux_record_tdep.size_pollfd = 8; 845 i386_linux_record_tdep.size_NFS_FHSIZE = 32; 846 i386_linux_record_tdep.size_knfsd_fh = 132; 847 i386_linux_record_tdep.size_TASK_COMM_LEN = 16; 848 i386_linux_record_tdep.size_sigaction = 140; 849 i386_linux_record_tdep.size_sigset_t = 8; 850 i386_linux_record_tdep.size_siginfo_t = 128; 851 i386_linux_record_tdep.size_cap_user_data_t = 12; 852 i386_linux_record_tdep.size_stack_t = 12; 853 i386_linux_record_tdep.size_off_t = i386_linux_record_tdep.size_long; 854 i386_linux_record_tdep.size_stat64 = 96; 855 i386_linux_record_tdep.size_gid_t = 2; 856 i386_linux_record_tdep.size_uid_t = 2; 857 i386_linux_record_tdep.size_PAGE_SIZE = 4096; 858 i386_linux_record_tdep.size_flock64 = 24; 859 i386_linux_record_tdep.size_user_desc = 16; 860 i386_linux_record_tdep.size_io_event = 32; 861 i386_linux_record_tdep.size_iocb = 64; 862 i386_linux_record_tdep.size_epoll_event = 12; 863 i386_linux_record_tdep.size_itimerspec 864 = i386_linux_record_tdep.size_timespec * 2; 865 i386_linux_record_tdep.size_mq_attr = 32; 866 i386_linux_record_tdep.size_siginfo = 128; 867 i386_linux_record_tdep.size_termios = 36; 868 i386_linux_record_tdep.size_termios2 = 44; 869 i386_linux_record_tdep.size_pid_t = 4; 870 i386_linux_record_tdep.size_winsize = 8; 871 i386_linux_record_tdep.size_serial_struct = 60; 872 i386_linux_record_tdep.size_serial_icounter_struct = 80; 873 i386_linux_record_tdep.size_hayes_esp_config = 12; 874 i386_linux_record_tdep.size_size_t = 4; 875 i386_linux_record_tdep.size_iovec = 8; 876 877 /* These values are the second argument of system call "sys_ioctl". 878 They are obtained from Linux Kernel source. */ 879 i386_linux_record_tdep.ioctl_TCGETS = 0x5401; 880 i386_linux_record_tdep.ioctl_TCSETS = 0x5402; 881 i386_linux_record_tdep.ioctl_TCSETSW = 0x5403; 882 i386_linux_record_tdep.ioctl_TCSETSF = 0x5404; 883 i386_linux_record_tdep.ioctl_TCGETA = 0x5405; 884 i386_linux_record_tdep.ioctl_TCSETA = 0x5406; 885 i386_linux_record_tdep.ioctl_TCSETAW = 0x5407; 886 i386_linux_record_tdep.ioctl_TCSETAF = 0x5408; 887 i386_linux_record_tdep.ioctl_TCSBRK = 0x5409; 888 i386_linux_record_tdep.ioctl_TCXONC = 0x540A; 889 i386_linux_record_tdep.ioctl_TCFLSH = 0x540B; 890 i386_linux_record_tdep.ioctl_TIOCEXCL = 0x540C; 891 i386_linux_record_tdep.ioctl_TIOCNXCL = 0x540D; 892 i386_linux_record_tdep.ioctl_TIOCSCTTY = 0x540E; 893 i386_linux_record_tdep.ioctl_TIOCGPGRP = 0x540F; 894 i386_linux_record_tdep.ioctl_TIOCSPGRP = 0x5410; 895 i386_linux_record_tdep.ioctl_TIOCOUTQ = 0x5411; 896 i386_linux_record_tdep.ioctl_TIOCSTI = 0x5412; 897 i386_linux_record_tdep.ioctl_TIOCGWINSZ = 0x5413; 898 i386_linux_record_tdep.ioctl_TIOCSWINSZ = 0x5414; 899 i386_linux_record_tdep.ioctl_TIOCMGET = 0x5415; 900 i386_linux_record_tdep.ioctl_TIOCMBIS = 0x5416; 901 i386_linux_record_tdep.ioctl_TIOCMBIC = 0x5417; 902 i386_linux_record_tdep.ioctl_TIOCMSET = 0x5418; 903 i386_linux_record_tdep.ioctl_TIOCGSOFTCAR = 0x5419; 904 i386_linux_record_tdep.ioctl_TIOCSSOFTCAR = 0x541A; 905 i386_linux_record_tdep.ioctl_FIONREAD = 0x541B; 906 i386_linux_record_tdep.ioctl_TIOCINQ = i386_linux_record_tdep.ioctl_FIONREAD; 907 i386_linux_record_tdep.ioctl_TIOCLINUX = 0x541C; 908 i386_linux_record_tdep.ioctl_TIOCCONS = 0x541D; 909 i386_linux_record_tdep.ioctl_TIOCGSERIAL = 0x541E; 910 i386_linux_record_tdep.ioctl_TIOCSSERIAL = 0x541F; 911 i386_linux_record_tdep.ioctl_TIOCPKT = 0x5420; 912 i386_linux_record_tdep.ioctl_FIONBIO = 0x5421; 913 i386_linux_record_tdep.ioctl_TIOCNOTTY = 0x5422; 914 i386_linux_record_tdep.ioctl_TIOCSETD = 0x5423; 915 i386_linux_record_tdep.ioctl_TIOCGETD = 0x5424; 916 i386_linux_record_tdep.ioctl_TCSBRKP = 0x5425; 917 i386_linux_record_tdep.ioctl_TIOCTTYGSTRUCT = 0x5426; 918 i386_linux_record_tdep.ioctl_TIOCSBRK = 0x5427; 919 i386_linux_record_tdep.ioctl_TIOCCBRK = 0x5428; 920 i386_linux_record_tdep.ioctl_TIOCGSID = 0x5429; 921 i386_linux_record_tdep.ioctl_TCGETS2 = 0x802c542a; 922 i386_linux_record_tdep.ioctl_TCSETS2 = 0x402c542b; 923 i386_linux_record_tdep.ioctl_TCSETSW2 = 0x402c542c; 924 i386_linux_record_tdep.ioctl_TCSETSF2 = 0x402c542d; 925 i386_linux_record_tdep.ioctl_TIOCGPTN = 0x80045430; 926 i386_linux_record_tdep.ioctl_TIOCSPTLCK = 0x40045431; 927 i386_linux_record_tdep.ioctl_FIONCLEX = 0x5450; 928 i386_linux_record_tdep.ioctl_FIOCLEX = 0x5451; 929 i386_linux_record_tdep.ioctl_FIOASYNC = 0x5452; 930 i386_linux_record_tdep.ioctl_TIOCSERCONFIG = 0x5453; 931 i386_linux_record_tdep.ioctl_TIOCSERGWILD = 0x5454; 932 i386_linux_record_tdep.ioctl_TIOCSERSWILD = 0x5455; 933 i386_linux_record_tdep.ioctl_TIOCGLCKTRMIOS = 0x5456; 934 i386_linux_record_tdep.ioctl_TIOCSLCKTRMIOS = 0x5457; 935 i386_linux_record_tdep.ioctl_TIOCSERGSTRUCT = 0x5458; 936 i386_linux_record_tdep.ioctl_TIOCSERGETLSR = 0x5459; 937 i386_linux_record_tdep.ioctl_TIOCSERGETMULTI = 0x545A; 938 i386_linux_record_tdep.ioctl_TIOCSERSETMULTI = 0x545B; 939 i386_linux_record_tdep.ioctl_TIOCMIWAIT = 0x545C; 940 i386_linux_record_tdep.ioctl_TIOCGICOUNT = 0x545D; 941 i386_linux_record_tdep.ioctl_TIOCGHAYESESP = 0x545E; 942 i386_linux_record_tdep.ioctl_TIOCSHAYESESP = 0x545F; 943 i386_linux_record_tdep.ioctl_FIOQSIZE = 0x5460; 944 945 /* These values are the second argument of system call "sys_fcntl" 946 and "sys_fcntl64". They are obtained from Linux Kernel source. */ 947 i386_linux_record_tdep.fcntl_F_GETLK = 5; 948 i386_linux_record_tdep.fcntl_F_GETLK64 = 12; 949 i386_linux_record_tdep.fcntl_F_SETLK64 = 13; 950 i386_linux_record_tdep.fcntl_F_SETLKW64 = 14; 951 952 i386_linux_record_tdep.arg1 = I386_EBX_REGNUM; 953 i386_linux_record_tdep.arg2 = I386_ECX_REGNUM; 954 i386_linux_record_tdep.arg3 = I386_EDX_REGNUM; 955 i386_linux_record_tdep.arg4 = I386_ESI_REGNUM; 956 i386_linux_record_tdep.arg5 = I386_EDI_REGNUM; 957 i386_linux_record_tdep.arg6 = I386_EBP_REGNUM; 958 959 tdep->i386_intx80_record = i386_linux_intx80_sysenter_syscall_record; 960 tdep->i386_sysenter_record = i386_linux_intx80_sysenter_syscall_record; 961 tdep->i386_syscall_record = i386_linux_intx80_sysenter_syscall_record; 962 963 /* N_FUN symbols in shared libaries have 0 for their values and need 964 to be relocated. */ 965 set_gdbarch_sofun_address_maybe_missing (gdbarch, 1); 966 967 /* GNU/Linux uses SVR4-style shared libraries. */ 968 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 969 set_solib_svr4_fetch_link_map_offsets 970 (gdbarch, svr4_ilp32_fetch_link_map_offsets); 971 972 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ 973 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 974 975 dwarf2_frame_set_signal_frame_p (gdbarch, i386_linux_dwarf_signal_frame_p); 976 977 /* Enable TLS support. */ 978 set_gdbarch_fetch_tls_load_module_address (gdbarch, 979 svr4_fetch_objfile_link_map); 980 981 /* Core file support. */ 982 set_gdbarch_iterate_over_regset_sections 983 (gdbarch, i386_linux_iterate_over_regset_sections); 984 set_gdbarch_core_read_description (gdbarch, 985 i386_linux_core_read_description); 986 987 /* Displaced stepping. */ 988 set_gdbarch_displaced_step_copy_insn (gdbarch, 989 i386_linux_displaced_step_copy_insn); 990 set_gdbarch_displaced_step_fixup (gdbarch, i386_displaced_step_fixup); 991 set_gdbarch_displaced_step_free_closure (gdbarch, 992 simple_displaced_step_free_closure); 993 set_gdbarch_displaced_step_location (gdbarch, 994 displaced_step_at_entry_point); 995 996 /* Functions for 'catch syscall'. */ 997 set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_I386); 998 set_gdbarch_get_syscall_number (gdbarch, 999 i386_linux_get_syscall_number); 1000 1001 set_gdbarch_get_siginfo_type (gdbarch, linux_get_siginfo_type); 1002 } 1003 1004 /* Provide a prototype to silence -Wmissing-prototypes. */ 1005 extern void _initialize_i386_linux_tdep (void); 1006 1007 void 1008 _initialize_i386_linux_tdep (void) 1009 { 1010 gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_LINUX, 1011 i386_linux_init_abi); 1012 1013 /* Initialize the Linux target description. */ 1014 initialize_tdesc_i386_linux (); 1015 initialize_tdesc_i386_mmx_linux (); 1016 initialize_tdesc_i386_avx_linux (); 1017 initialize_tdesc_i386_mpx_linux (); 1018 initialize_tdesc_i386_avx512_linux (); 1019 } 1020