| 1 | /* Native-dependent code for GNU/Linux i386. |
| 2 | |
| 3 | Copyright (C) 1999-2019 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 "inferior.h" |
| 22 | #include "gdbcore.h" |
| 23 | #include "regcache.h" |
| 24 | #include "elf/common.h" |
| 25 | #include "nat/gdb_ptrace.h" |
| 26 | #include <sys/uio.h> |
| 27 | #include "gregset.h" |
| 28 | #include "gdb_proc_service.h" |
| 29 | |
| 30 | #include "i386-linux-nat.h" |
| 31 | #include "i387-tdep.h" |
| 32 | #include "i386-tdep.h" |
| 33 | #include "i386-linux-tdep.h" |
| 34 | #include "gdbsupport/x86-xstate.h" |
| 35 | |
| 36 | #include "x86-linux-nat.h" |
| 37 | #include "nat/linux-ptrace.h" |
| 38 | #include "inf-ptrace.h" |
| 39 | |
| 40 | struct i386_linux_nat_target final : public x86_linux_nat_target |
| 41 | { |
| 42 | /* Add our register access methods. */ |
| 43 | void fetch_registers (struct regcache *, int) override; |
| 44 | void store_registers (struct regcache *, int) override; |
| 45 | |
| 46 | /* Override the default ptrace resume method. */ |
| 47 | void low_resume (ptid_t ptid, int step, enum gdb_signal sig) override; |
| 48 | }; |
| 49 | |
| 50 | static i386_linux_nat_target the_i386_linux_nat_target; |
| 51 | |
| 52 | /* The register sets used in GNU/Linux ELF core-dumps are identical to |
| 53 | the register sets in `struct user' that is used for a.out |
| 54 | core-dumps, and is also used by `ptrace'. The corresponding types |
| 55 | are `elf_gregset_t' for the general-purpose registers (with |
| 56 | `elf_greg_t' the type of a single GP register) and `elf_fpregset_t' |
| 57 | for the floating-point registers. |
| 58 | |
| 59 | Those types used to be available under the names `gregset_t' and |
| 60 | `fpregset_t' too, and this file used those names in the past. But |
| 61 | those names are now used for the register sets used in the |
| 62 | `mcontext_t' type, and have a different size and layout. */ |
| 63 | |
| 64 | /* Which ptrace request retrieves which registers? |
| 65 | These apply to the corresponding SET requests as well. */ |
| 66 | |
| 67 | #define GETREGS_SUPPLIES(regno) \ |
| 68 | ((0 <= (regno) && (regno) <= 15) || (regno) == I386_LINUX_ORIG_EAX_REGNUM) |
| 69 | |
| 70 | #define GETFPXREGS_SUPPLIES(regno) \ |
| 71 | (I386_ST0_REGNUM <= (regno) && (regno) < I386_SSE_NUM_REGS) |
| 72 | |
| 73 | #define GETXSTATEREGS_SUPPLIES(regno) \ |
| 74 | (I386_ST0_REGNUM <= (regno) && (regno) < I386_PKEYS_NUM_REGS) |
| 75 | |
| 76 | /* Does the current host support the GETREGS request? */ |
| 77 | int have_ptrace_getregs = |
| 78 | #ifdef HAVE_PTRACE_GETREGS |
| 79 | 1 |
| 80 | #else |
| 81 | 0 |
| 82 | #endif |
| 83 | ; |
| 84 | |
| 85 | /* Does the current host support the GETFPXREGS request? The header |
| 86 | file may or may not define it, and even if it is defined, the |
| 87 | kernel will return EIO if it's running on a pre-SSE processor. |
| 88 | |
| 89 | My instinct is to attach this to some architecture- or |
| 90 | target-specific data structure, but really, a particular GDB |
| 91 | process can only run on top of one kernel at a time. So it's okay |
| 92 | for this to be a simple variable. */ |
| 93 | int have_ptrace_getfpxregs = |
| 94 | #ifdef HAVE_PTRACE_GETFPXREGS |
| 95 | -1 |
| 96 | #else |
| 97 | 0 |
| 98 | #endif |
| 99 | ; |
| 100 | \f |
| 101 | |
| 102 | /* Accessing registers through the U area, one at a time. */ |
| 103 | |
| 104 | /* Fetch one register. */ |
| 105 | |
| 106 | static void |
| 107 | fetch_register (struct regcache *regcache, int regno) |
| 108 | { |
| 109 | pid_t tid; |
| 110 | int val; |
| 111 | |
| 112 | gdb_assert (!have_ptrace_getregs); |
| 113 | if (i386_linux_gregset_reg_offset[regno] == -1) |
| 114 | { |
| 115 | regcache->raw_supply (regno, NULL); |
| 116 | return; |
| 117 | } |
| 118 | |
| 119 | tid = get_ptrace_pid (regcache->ptid ()); |
| 120 | |
| 121 | errno = 0; |
| 122 | val = ptrace (PTRACE_PEEKUSER, tid, |
| 123 | i386_linux_gregset_reg_offset[regno], 0); |
| 124 | if (errno != 0) |
| 125 | error (_("Couldn't read register %s (#%d): %s."), |
| 126 | gdbarch_register_name (regcache->arch (), regno), |
| 127 | regno, safe_strerror (errno)); |
| 128 | |
| 129 | regcache->raw_supply (regno, &val); |
| 130 | } |
| 131 | |
| 132 | /* Store one register. */ |
| 133 | |
| 134 | static void |
| 135 | store_register (const struct regcache *regcache, int regno) |
| 136 | { |
| 137 | pid_t tid; |
| 138 | int val; |
| 139 | |
| 140 | gdb_assert (!have_ptrace_getregs); |
| 141 | if (i386_linux_gregset_reg_offset[regno] == -1) |
| 142 | return; |
| 143 | |
| 144 | tid = get_ptrace_pid (regcache->ptid ()); |
| 145 | |
| 146 | errno = 0; |
| 147 | regcache->raw_collect (regno, &val); |
| 148 | ptrace (PTRACE_POKEUSER, tid, |
| 149 | i386_linux_gregset_reg_offset[regno], val); |
| 150 | if (errno != 0) |
| 151 | error (_("Couldn't write register %s (#%d): %s."), |
| 152 | gdbarch_register_name (regcache->arch (), regno), |
| 153 | regno, safe_strerror (errno)); |
| 154 | } |
| 155 | \f |
| 156 | |
| 157 | /* Transfering the general-purpose registers between GDB, inferiors |
| 158 | and core files. */ |
| 159 | |
| 160 | /* Fill GDB's register array with the general-purpose register values |
| 161 | in *GREGSETP. */ |
| 162 | |
| 163 | void |
| 164 | supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp) |
| 165 | { |
| 166 | const gdb_byte *regp = (const gdb_byte *) gregsetp; |
| 167 | int i; |
| 168 | |
| 169 | for (i = 0; i < I386_NUM_GREGS; i++) |
| 170 | regcache->raw_supply (i, regp + i386_linux_gregset_reg_offset[i]); |
| 171 | |
| 172 | if (I386_LINUX_ORIG_EAX_REGNUM |
| 173 | < gdbarch_num_regs (regcache->arch ())) |
| 174 | regcache->raw_supply |
| 175 | (I386_LINUX_ORIG_EAX_REGNUM, |
| 176 | regp + i386_linux_gregset_reg_offset[I386_LINUX_ORIG_EAX_REGNUM]); |
| 177 | } |
| 178 | |
| 179 | /* Fill register REGNO (if it is a general-purpose register) in |
| 180 | *GREGSETPS with the value in GDB's register array. If REGNO is -1, |
| 181 | do this for all registers. */ |
| 182 | |
| 183 | void |
| 184 | fill_gregset (const struct regcache *regcache, |
| 185 | elf_gregset_t *gregsetp, int regno) |
| 186 | { |
| 187 | gdb_byte *regp = (gdb_byte *) gregsetp; |
| 188 | int i; |
| 189 | |
| 190 | for (i = 0; i < I386_NUM_GREGS; i++) |
| 191 | if (regno == -1 || regno == i) |
| 192 | regcache->raw_collect (i, regp + i386_linux_gregset_reg_offset[i]); |
| 193 | |
| 194 | if ((regno == -1 || regno == I386_LINUX_ORIG_EAX_REGNUM) |
| 195 | && I386_LINUX_ORIG_EAX_REGNUM |
| 196 | < gdbarch_num_regs (regcache->arch ())) |
| 197 | regcache->raw_collect |
| 198 | (I386_LINUX_ORIG_EAX_REGNUM, |
| 199 | regp + i386_linux_gregset_reg_offset[I386_LINUX_ORIG_EAX_REGNUM]); |
| 200 | } |
| 201 | |
| 202 | #ifdef HAVE_PTRACE_GETREGS |
| 203 | |
| 204 | /* Fetch all general-purpose registers from process/thread TID and |
| 205 | store their values in GDB's register array. */ |
| 206 | |
| 207 | static void |
| 208 | fetch_regs (struct regcache *regcache, int tid) |
| 209 | { |
| 210 | elf_gregset_t regs; |
| 211 | elf_gregset_t *regs_p = ®s; |
| 212 | |
| 213 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) |
| 214 | { |
| 215 | if (errno == EIO) |
| 216 | { |
| 217 | /* The kernel we're running on doesn't support the GETREGS |
| 218 | request. Reset `have_ptrace_getregs'. */ |
| 219 | have_ptrace_getregs = 0; |
| 220 | return; |
| 221 | } |
| 222 | |
| 223 | perror_with_name (_("Couldn't get registers")); |
| 224 | } |
| 225 | |
| 226 | supply_gregset (regcache, (const elf_gregset_t *) regs_p); |
| 227 | } |
| 228 | |
| 229 | /* Store all valid general-purpose registers in GDB's register array |
| 230 | into the process/thread specified by TID. */ |
| 231 | |
| 232 | static void |
| 233 | store_regs (const struct regcache *regcache, int tid, int regno) |
| 234 | { |
| 235 | elf_gregset_t regs; |
| 236 | |
| 237 | if (ptrace (PTRACE_GETREGS, tid, 0, (int) ®s) < 0) |
| 238 | perror_with_name (_("Couldn't get registers")); |
| 239 | |
| 240 | fill_gregset (regcache, ®s, regno); |
| 241 | |
| 242 | if (ptrace (PTRACE_SETREGS, tid, 0, (int) ®s) < 0) |
| 243 | perror_with_name (_("Couldn't write registers")); |
| 244 | } |
| 245 | |
| 246 | #else |
| 247 | |
| 248 | static void fetch_regs (struct regcache *regcache, int tid) {} |
| 249 | static void store_regs (const struct regcache *regcache, int tid, int regno) {} |
| 250 | |
| 251 | #endif |
| 252 | \f |
| 253 | |
| 254 | /* Transfering floating-point registers between GDB, inferiors and cores. */ |
| 255 | |
| 256 | /* Fill GDB's register array with the floating-point register values in |
| 257 | *FPREGSETP. */ |
| 258 | |
| 259 | void |
| 260 | supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp) |
| 261 | { |
| 262 | i387_supply_fsave (regcache, -1, fpregsetp); |
| 263 | } |
| 264 | |
| 265 | /* Fill register REGNO (if it is a floating-point register) in |
| 266 | *FPREGSETP with the value in GDB's register array. If REGNO is -1, |
| 267 | do this for all registers. */ |
| 268 | |
| 269 | void |
| 270 | fill_fpregset (const struct regcache *regcache, |
| 271 | elf_fpregset_t *fpregsetp, int regno) |
| 272 | { |
| 273 | i387_collect_fsave (regcache, regno, fpregsetp); |
| 274 | } |
| 275 | |
| 276 | #ifdef HAVE_PTRACE_GETREGS |
| 277 | |
| 278 | /* Fetch all floating-point registers from process/thread TID and store |
| 279 | thier values in GDB's register array. */ |
| 280 | |
| 281 | static void |
| 282 | fetch_fpregs (struct regcache *regcache, int tid) |
| 283 | { |
| 284 | elf_fpregset_t fpregs; |
| 285 | |
| 286 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) |
| 287 | perror_with_name (_("Couldn't get floating point status")); |
| 288 | |
| 289 | supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs); |
| 290 | } |
| 291 | |
| 292 | /* Store all valid floating-point registers in GDB's register array |
| 293 | into the process/thread specified by TID. */ |
| 294 | |
| 295 | static void |
| 296 | store_fpregs (const struct regcache *regcache, int tid, int regno) |
| 297 | { |
| 298 | elf_fpregset_t fpregs; |
| 299 | |
| 300 | if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0) |
| 301 | perror_with_name (_("Couldn't get floating point status")); |
| 302 | |
| 303 | fill_fpregset (regcache, &fpregs, regno); |
| 304 | |
| 305 | if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0) |
| 306 | perror_with_name (_("Couldn't write floating point status")); |
| 307 | } |
| 308 | |
| 309 | #else |
| 310 | |
| 311 | static void |
| 312 | fetch_fpregs (struct regcache *regcache, int tid) |
| 313 | { |
| 314 | } |
| 315 | |
| 316 | static void |
| 317 | store_fpregs (const struct regcache *regcache, int tid, int regno) |
| 318 | { |
| 319 | } |
| 320 | |
| 321 | #endif |
| 322 | \f |
| 323 | |
| 324 | /* Transfering floating-point and SSE registers to and from GDB. */ |
| 325 | |
| 326 | /* Fetch all registers covered by the PTRACE_GETREGSET request from |
| 327 | process/thread TID and store their values in GDB's register array. |
| 328 | Return non-zero if successful, zero otherwise. */ |
| 329 | |
| 330 | static int |
| 331 | fetch_xstateregs (struct regcache *regcache, int tid) |
| 332 | { |
| 333 | char xstateregs[X86_XSTATE_MAX_SIZE]; |
| 334 | struct iovec iov; |
| 335 | |
| 336 | if (have_ptrace_getregset != TRIBOOL_TRUE) |
| 337 | return 0; |
| 338 | |
| 339 | iov.iov_base = xstateregs; |
| 340 | iov.iov_len = sizeof(xstateregs); |
| 341 | if (ptrace (PTRACE_GETREGSET, tid, (unsigned int) NT_X86_XSTATE, |
| 342 | &iov) < 0) |
| 343 | perror_with_name (_("Couldn't read extended state status")); |
| 344 | |
| 345 | i387_supply_xsave (regcache, -1, xstateregs); |
| 346 | return 1; |
| 347 | } |
| 348 | |
| 349 | /* Store all valid registers in GDB's register array covered by the |
| 350 | PTRACE_SETREGSET request into the process/thread specified by TID. |
| 351 | Return non-zero if successful, zero otherwise. */ |
| 352 | |
| 353 | static int |
| 354 | store_xstateregs (const struct regcache *regcache, int tid, int regno) |
| 355 | { |
| 356 | char xstateregs[X86_XSTATE_MAX_SIZE]; |
| 357 | struct iovec iov; |
| 358 | |
| 359 | if (have_ptrace_getregset != TRIBOOL_TRUE) |
| 360 | return 0; |
| 361 | |
| 362 | iov.iov_base = xstateregs; |
| 363 | iov.iov_len = sizeof(xstateregs); |
| 364 | if (ptrace (PTRACE_GETREGSET, tid, (unsigned int) NT_X86_XSTATE, |
| 365 | &iov) < 0) |
| 366 | perror_with_name (_("Couldn't read extended state status")); |
| 367 | |
| 368 | i387_collect_xsave (regcache, regno, xstateregs, 0); |
| 369 | |
| 370 | if (ptrace (PTRACE_SETREGSET, tid, (unsigned int) NT_X86_XSTATE, |
| 371 | (int) &iov) < 0) |
| 372 | perror_with_name (_("Couldn't write extended state status")); |
| 373 | |
| 374 | return 1; |
| 375 | } |
| 376 | |
| 377 | #ifdef HAVE_PTRACE_GETFPXREGS |
| 378 | |
| 379 | /* Fetch all registers covered by the PTRACE_GETFPXREGS request from |
| 380 | process/thread TID and store their values in GDB's register array. |
| 381 | Return non-zero if successful, zero otherwise. */ |
| 382 | |
| 383 | static int |
| 384 | fetch_fpxregs (struct regcache *regcache, int tid) |
| 385 | { |
| 386 | elf_fpxregset_t fpxregs; |
| 387 | |
| 388 | if (! have_ptrace_getfpxregs) |
| 389 | return 0; |
| 390 | |
| 391 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0) |
| 392 | { |
| 393 | if (errno == EIO) |
| 394 | { |
| 395 | have_ptrace_getfpxregs = 0; |
| 396 | return 0; |
| 397 | } |
| 398 | |
| 399 | perror_with_name (_("Couldn't read floating-point and SSE registers")); |
| 400 | } |
| 401 | |
| 402 | i387_supply_fxsave (regcache, -1, (const elf_fpxregset_t *) &fpxregs); |
| 403 | return 1; |
| 404 | } |
| 405 | |
| 406 | /* Store all valid registers in GDB's register array covered by the |
| 407 | PTRACE_SETFPXREGS request into the process/thread specified by TID. |
| 408 | Return non-zero if successful, zero otherwise. */ |
| 409 | |
| 410 | static int |
| 411 | store_fpxregs (const struct regcache *regcache, int tid, int regno) |
| 412 | { |
| 413 | elf_fpxregset_t fpxregs; |
| 414 | |
| 415 | if (! have_ptrace_getfpxregs) |
| 416 | return 0; |
| 417 | |
| 418 | if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1) |
| 419 | { |
| 420 | if (errno == EIO) |
| 421 | { |
| 422 | have_ptrace_getfpxregs = 0; |
| 423 | return 0; |
| 424 | } |
| 425 | |
| 426 | perror_with_name (_("Couldn't read floating-point and SSE registers")); |
| 427 | } |
| 428 | |
| 429 | i387_collect_fxsave (regcache, regno, &fpxregs); |
| 430 | |
| 431 | if (ptrace (PTRACE_SETFPXREGS, tid, 0, &fpxregs) == -1) |
| 432 | perror_with_name (_("Couldn't write floating-point and SSE registers")); |
| 433 | |
| 434 | return 1; |
| 435 | } |
| 436 | |
| 437 | #else |
| 438 | |
| 439 | static int |
| 440 | fetch_fpxregs (struct regcache *regcache, int tid) |
| 441 | { |
| 442 | return 0; |
| 443 | } |
| 444 | |
| 445 | static int |
| 446 | store_fpxregs (const struct regcache *regcache, int tid, int regno) |
| 447 | { |
| 448 | return 0; |
| 449 | } |
| 450 | |
| 451 | #endif /* HAVE_PTRACE_GETFPXREGS */ |
| 452 | \f |
| 453 | |
| 454 | /* Transferring arbitrary registers between GDB and inferior. */ |
| 455 | |
| 456 | /* Fetch register REGNO from the child process. If REGNO is -1, do |
| 457 | this for all registers (including the floating point and SSE |
| 458 | registers). */ |
| 459 | |
| 460 | void |
| 461 | i386_linux_nat_target::fetch_registers (struct regcache *regcache, int regno) |
| 462 | { |
| 463 | pid_t tid; |
| 464 | |
| 465 | /* Use the old method of peeking around in `struct user' if the |
| 466 | GETREGS request isn't available. */ |
| 467 | if (!have_ptrace_getregs) |
| 468 | { |
| 469 | int i; |
| 470 | |
| 471 | for (i = 0; i < gdbarch_num_regs (regcache->arch ()); i++) |
| 472 | if (regno == -1 || regno == i) |
| 473 | fetch_register (regcache, i); |
| 474 | |
| 475 | return; |
| 476 | } |
| 477 | |
| 478 | tid = get_ptrace_pid (regcache->ptid ()); |
| 479 | |
| 480 | /* Use the PTRACE_GETFPXREGS request whenever possible, since it |
| 481 | transfers more registers in one system call, and we'll cache the |
| 482 | results. But remember that fetch_fpxregs can fail, and return |
| 483 | zero. */ |
| 484 | if (regno == -1) |
| 485 | { |
| 486 | fetch_regs (regcache, tid); |
| 487 | |
| 488 | /* The call above might reset `have_ptrace_getregs'. */ |
| 489 | if (!have_ptrace_getregs) |
| 490 | { |
| 491 | fetch_registers (regcache, regno); |
| 492 | return; |
| 493 | } |
| 494 | |
| 495 | if (fetch_xstateregs (regcache, tid)) |
| 496 | return; |
| 497 | if (fetch_fpxregs (regcache, tid)) |
| 498 | return; |
| 499 | fetch_fpregs (regcache, tid); |
| 500 | return; |
| 501 | } |
| 502 | |
| 503 | if (GETREGS_SUPPLIES (regno)) |
| 504 | { |
| 505 | fetch_regs (regcache, tid); |
| 506 | return; |
| 507 | } |
| 508 | |
| 509 | if (GETXSTATEREGS_SUPPLIES (regno)) |
| 510 | { |
| 511 | if (fetch_xstateregs (regcache, tid)) |
| 512 | return; |
| 513 | } |
| 514 | |
| 515 | if (GETFPXREGS_SUPPLIES (regno)) |
| 516 | { |
| 517 | if (fetch_fpxregs (regcache, tid)) |
| 518 | return; |
| 519 | |
| 520 | /* Either our processor or our kernel doesn't support the SSE |
| 521 | registers, so read the FP registers in the traditional way, |
| 522 | and fill the SSE registers with dummy values. It would be |
| 523 | more graceful to handle differences in the register set using |
| 524 | gdbarch. Until then, this will at least make things work |
| 525 | plausibly. */ |
| 526 | fetch_fpregs (regcache, tid); |
| 527 | return; |
| 528 | } |
| 529 | |
| 530 | internal_error (__FILE__, __LINE__, |
| 531 | _("Got request for bad register number %d."), regno); |
| 532 | } |
| 533 | |
| 534 | /* Store register REGNO back into the child process. If REGNO is -1, |
| 535 | do this for all registers (including the floating point and SSE |
| 536 | registers). */ |
| 537 | void |
| 538 | i386_linux_nat_target::store_registers (struct regcache *regcache, int regno) |
| 539 | { |
| 540 | pid_t tid; |
| 541 | |
| 542 | /* Use the old method of poking around in `struct user' if the |
| 543 | SETREGS request isn't available. */ |
| 544 | if (!have_ptrace_getregs) |
| 545 | { |
| 546 | int i; |
| 547 | |
| 548 | for (i = 0; i < gdbarch_num_regs (regcache->arch ()); i++) |
| 549 | if (regno == -1 || regno == i) |
| 550 | store_register (regcache, i); |
| 551 | |
| 552 | return; |
| 553 | } |
| 554 | |
| 555 | tid = get_ptrace_pid (regcache->ptid ()); |
| 556 | |
| 557 | /* Use the PTRACE_SETFPXREGS requests whenever possible, since it |
| 558 | transfers more registers in one system call. But remember that |
| 559 | store_fpxregs can fail, and return zero. */ |
| 560 | if (regno == -1) |
| 561 | { |
| 562 | store_regs (regcache, tid, regno); |
| 563 | if (store_xstateregs (regcache, tid, regno)) |
| 564 | return; |
| 565 | if (store_fpxregs (regcache, tid, regno)) |
| 566 | return; |
| 567 | store_fpregs (regcache, tid, regno); |
| 568 | return; |
| 569 | } |
| 570 | |
| 571 | if (GETREGS_SUPPLIES (regno)) |
| 572 | { |
| 573 | store_regs (regcache, tid, regno); |
| 574 | return; |
| 575 | } |
| 576 | |
| 577 | if (GETXSTATEREGS_SUPPLIES (regno)) |
| 578 | { |
| 579 | if (store_xstateregs (regcache, tid, regno)) |
| 580 | return; |
| 581 | } |
| 582 | |
| 583 | if (GETFPXREGS_SUPPLIES (regno)) |
| 584 | { |
| 585 | if (store_fpxregs (regcache, tid, regno)) |
| 586 | return; |
| 587 | |
| 588 | /* Either our processor or our kernel doesn't support the SSE |
| 589 | registers, so just write the FP registers in the traditional |
| 590 | way. */ |
| 591 | store_fpregs (regcache, tid, regno); |
| 592 | return; |
| 593 | } |
| 594 | |
| 595 | internal_error (__FILE__, __LINE__, |
| 596 | _("Got request to store bad register number %d."), regno); |
| 597 | } |
| 598 | \f |
| 599 | |
| 600 | /* Called by libthread_db. Returns a pointer to the thread local |
| 601 | storage (or its descriptor). */ |
| 602 | |
| 603 | ps_err_e |
| 604 | ps_get_thread_area (struct ps_prochandle *ph, |
| 605 | lwpid_t lwpid, int idx, void **base) |
| 606 | { |
| 607 | unsigned int base_addr; |
| 608 | ps_err_e result; |
| 609 | |
| 610 | result = x86_linux_get_thread_area (lwpid, (void *) idx, &base_addr); |
| 611 | |
| 612 | if (result == PS_OK) |
| 613 | *(int *) base = base_addr; |
| 614 | |
| 615 | return result; |
| 616 | } |
| 617 | \f |
| 618 | |
| 619 | /* The instruction for a GNU/Linux system call is: |
| 620 | int $0x80 |
| 621 | or 0xcd 0x80. */ |
| 622 | |
| 623 | static const unsigned char linux_syscall[] = { 0xcd, 0x80 }; |
| 624 | |
| 625 | #define LINUX_SYSCALL_LEN (sizeof linux_syscall) |
| 626 | |
| 627 | /* The system call number is stored in the %eax register. */ |
| 628 | #define LINUX_SYSCALL_REGNUM I386_EAX_REGNUM |
| 629 | |
| 630 | /* We are specifically interested in the sigreturn and rt_sigreturn |
| 631 | system calls. */ |
| 632 | |
| 633 | #ifndef SYS_sigreturn |
| 634 | #define SYS_sigreturn 0x77 |
| 635 | #endif |
| 636 | #ifndef SYS_rt_sigreturn |
| 637 | #define SYS_rt_sigreturn 0xad |
| 638 | #endif |
| 639 | |
| 640 | /* Offset to saved processor flags, from <asm/sigcontext.h>. */ |
| 641 | #define LINUX_SIGCONTEXT_EFLAGS_OFFSET (64) |
| 642 | |
| 643 | /* Resume execution of the inferior process. |
| 644 | If STEP is nonzero, single-step it. |
| 645 | If SIGNAL is nonzero, give it that signal. */ |
| 646 | |
| 647 | void |
| 648 | i386_linux_nat_target::low_resume (ptid_t ptid, int step, enum gdb_signal signal) |
| 649 | { |
| 650 | int pid = ptid.lwp (); |
| 651 | int request; |
| 652 | |
| 653 | if (catch_syscall_enabled () > 0) |
| 654 | request = PTRACE_SYSCALL; |
| 655 | else |
| 656 | request = PTRACE_CONT; |
| 657 | |
| 658 | if (step) |
| 659 | { |
| 660 | struct regcache *regcache = get_thread_regcache (ptid); |
| 661 | struct gdbarch *gdbarch = regcache->arch (); |
| 662 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 663 | ULONGEST pc; |
| 664 | gdb_byte buf[LINUX_SYSCALL_LEN]; |
| 665 | |
| 666 | request = PTRACE_SINGLESTEP; |
| 667 | |
| 668 | regcache_cooked_read_unsigned (regcache, |
| 669 | gdbarch_pc_regnum (gdbarch), &pc); |
| 670 | |
| 671 | /* Returning from a signal trampoline is done by calling a |
| 672 | special system call (sigreturn or rt_sigreturn, see |
| 673 | i386-linux-tdep.c for more information). This system call |
| 674 | restores the registers that were saved when the signal was |
| 675 | raised, including %eflags. That means that single-stepping |
| 676 | won't work. Instead, we'll have to modify the signal context |
| 677 | that's about to be restored, and set the trace flag there. */ |
| 678 | |
| 679 | /* First check if PC is at a system call. */ |
| 680 | if (target_read_memory (pc, buf, LINUX_SYSCALL_LEN) == 0 |
| 681 | && memcmp (buf, linux_syscall, LINUX_SYSCALL_LEN) == 0) |
| 682 | { |
| 683 | ULONGEST syscall; |
| 684 | regcache_cooked_read_unsigned (regcache, |
| 685 | LINUX_SYSCALL_REGNUM, &syscall); |
| 686 | |
| 687 | /* Then check the system call number. */ |
| 688 | if (syscall == SYS_sigreturn || syscall == SYS_rt_sigreturn) |
| 689 | { |
| 690 | ULONGEST sp, addr; |
| 691 | unsigned long int eflags; |
| 692 | |
| 693 | regcache_cooked_read_unsigned (regcache, I386_ESP_REGNUM, &sp); |
| 694 | if (syscall == SYS_rt_sigreturn) |
| 695 | addr = read_memory_unsigned_integer (sp + 8, 4, byte_order) |
| 696 | + 20; |
| 697 | else |
| 698 | addr = sp; |
| 699 | |
| 700 | /* Set the trace flag in the context that's about to be |
| 701 | restored. */ |
| 702 | addr += LINUX_SIGCONTEXT_EFLAGS_OFFSET; |
| 703 | read_memory (addr, (gdb_byte *) &eflags, 4); |
| 704 | eflags |= 0x0100; |
| 705 | write_memory (addr, (gdb_byte *) &eflags, 4); |
| 706 | } |
| 707 | } |
| 708 | } |
| 709 | |
| 710 | if (ptrace (request, pid, 0, gdb_signal_to_host (signal)) == -1) |
| 711 | perror_with_name (("ptrace")); |
| 712 | } |
| 713 | |
| 714 | void |
| 715 | _initialize_i386_linux_nat (void) |
| 716 | { |
| 717 | linux_target = &the_i386_linux_nat_target; |
| 718 | |
| 719 | /* Add the target. */ |
| 720 | add_inf_child_target (linux_target); |
| 721 | } |