gdb/gdbserver/linux-x86-low.c

   1 /* GNU/Linux/x86-64 specific low level interface, for the remote server
   2    for GDB.
   3    Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include "server.h"
  24 #include "linux-low.h"
  25 #include "i387-fp.h"
  26 #include "i386-low.h"
  27 #include "i386-xstate.h"
  28 #include "elf/common.h"
  29
  30 #include "gdb_proc_service.h"
  31
  32 /* Defined in auto-generated file i386-linux.c.  */
  33 void init_registers_i386_linux (void);
  34 /* Defined in auto-generated file amd64-linux.c.  */
  35 void init_registers_amd64_linux (void);
  36 /* Defined in auto-generated file i386-avx-linux.c.  */
  37 void init_registers_i386_avx_linux (void);
  38 /* Defined in auto-generated file amd64-avx-linux.c.  */
  39 void init_registers_amd64_avx_linux (void);
  40
  41 /* Backward compatibility for gdb without XML support.  */
  42
  43 static const char *xmltarget_i386_linux_no_xml = "@<target>\
  44 <architecture>i386</architecture>\
  45 <osabi>GNU/Linux</osabi>\
  46 </target>";
  47 static const char *xmltarget_amd64_linux_no_xml = "@<target>\
  48 <architecture>i386:x86-64</architecture>\
  49 <osabi>GNU/Linux</osabi>\
  50 </target>";
  51
  52 #include <sys/reg.h>
  53 #include <sys/procfs.h>
  54 #include <sys/ptrace.h>
  55 #include <sys/uio.h>
  56
  57 #ifndef PTRACE_GETREGSET
  58 #define PTRACE_GETREGSET        0x4204
  59 #endif
  60
  61 #ifndef PTRACE_SETREGSET
  62 #define PTRACE_SETREGSET        0x4205
  63 #endif
  64
  65
  66 #ifndef PTRACE_GET_THREAD_AREA
  67 #define PTRACE_GET_THREAD_AREA 25
  68 #endif
  69
  70 /* This definition comes from prctl.h, but some kernels may not have it.  */
  71 #ifndef PTRACE_ARCH_PRCTL
  72 #define PTRACE_ARCH_PRCTL      30
  73 #endif
  74
  75 /* The following definitions come from prctl.h, but may be absent
  76    for certain configurations.  */
  77 #ifndef ARCH_GET_FS
  78 #define ARCH_SET_GS 0x1001
  79 #define ARCH_SET_FS 0x1002
  80 #define ARCH_GET_FS 0x1003
  81 #define ARCH_GET_GS 0x1004
  82 #endif
  83
  84 /* Per-process arch-specific data we want to keep.  */
  85
  86 struct arch_process_info
  87 {
  88   struct i386_debug_reg_state debug_reg_state;
  89 };
  90
  91 /* Per-thread arch-specific data we want to keep.  */
  92
  93 struct arch_lwp_info
  94 {
  95   /* Non-zero if our copy differs from what's recorded in the thread.  */
  96   int debug_registers_changed;
  97 };
  98
  99 #ifdef __x86_64__
 100
 101 /* Mapping between the general-purpose registers in `struct user'
 102    format and GDB's register array layout.
 103    Note that the transfer layout uses 64-bit regs.  */
 104 static /*const*/ int i386_regmap[] =
 105 {
 106   RAX * 8, RCX * 8, RDX * 8, RBX * 8,
 107   RSP * 8, RBP * 8, RSI * 8, RDI * 8,
 108   RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
 109   DS * 8, ES * 8, FS * 8, GS * 8
 110 };
 111
 112 #define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
 113
 114 /* So code below doesn't have to care, i386 or amd64.  */
 115 #define ORIG_EAX ORIG_RAX
 116
 117 static const int x86_64_regmap[] =
 118 {
 119   RAX * 8, RBX * 8, RCX * 8, RDX * 8,
 120   RSI * 8, RDI * 8, RBP * 8, RSP * 8,
 121   R8 * 8, R9 * 8, R10 * 8, R11 * 8,
 122   R12 * 8, R13 * 8, R14 * 8, R15 * 8,
 123   RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
 124   DS * 8, ES * 8, FS * 8, GS * 8,
 125   -1, -1, -1, -1, -1, -1, -1, -1,
 126   -1, -1, -1, -1, -1, -1, -1, -1,
 127   -1, -1, -1, -1, -1, -1, -1, -1,
 128   -1, -1, -1, -1, -1, -1, -1, -1, -1,
 129   ORIG_RAX * 8
 130 };
 131
 132 #define X86_64_NUM_REGS (sizeof (x86_64_regmap) / sizeof (x86_64_regmap[0]))
 133
 134 #else /* ! __x86_64__ */
 135
 136 /* Mapping between the general-purpose registers in `struct user'
 137    format and GDB's register array layout.  */
 138 static /*const*/ int i386_regmap[] =
 139 {
 140   EAX * 4, ECX * 4, EDX * 4, EBX * 4,
 141   UESP * 4, EBP * 4, ESI * 4, EDI * 4,
 142   EIP * 4, EFL * 4, CS * 4, SS * 4,
 143   DS * 4, ES * 4, FS * 4, GS * 4
 144 };
 145
 146 #define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
 147
 148 #endif
 149 \f
 150 /* Called by libthread_db.  */
 151
 152 ps_err_e
 153 ps_get_thread_area (const struct ps_prochandle *ph,
 154                     lwpid_t lwpid, int idx, void **base)
 155 {
 156 #ifdef __x86_64__
 157   int use_64bit = register_size (0) == 8;
 158
 159   if (use_64bit)
 160     {
 161       switch (idx)
 162         {
 163         case FS:
 164           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 165             return PS_OK;
 166           break;
 167         case GS:
 168           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 169             return PS_OK;
 170           break;
 171         default:
 172           return PS_BADADDR;
 173         }
 174       return PS_ERR;
 175     }
 176 #endif
 177
 178   {
 179     unsigned int desc[4];
 180
 181     if (ptrace (PTRACE_GET_THREAD_AREA, lwpid,
 182                 (void *) (intptr_t) idx, (unsigned long) &desc) < 0)
 183       return PS_ERR;
 184
 185     *(int *)base = desc[1];
 186     return PS_OK;
 187   }
 188 }
 189 \f
 190 static int
 191 i386_cannot_store_register (int regno)
 192 {
 193   return regno >= I386_NUM_REGS;
 194 }
 195
 196 static int
 197 i386_cannot_fetch_register (int regno)
 198 {
 199   return regno >= I386_NUM_REGS;
 200 }
 201
 202 static void
 203 x86_fill_gregset (struct regcache *regcache, void *buf)
 204 {
 205   int i;
 206
 207 #ifdef __x86_64__
 208   if (register_size (0) == 8)
 209     {
 210       for (i = 0; i < X86_64_NUM_REGS; i++)
 211         if (x86_64_regmap[i] != -1)
 212           collect_register (regcache, i, ((char *) buf) + x86_64_regmap[i]);
 213       return;
 214     }
 215 #endif
 216
 217   for (i = 0; i < I386_NUM_REGS; i++)
 218     collect_register (regcache, i, ((char *) buf) + i386_regmap[i]);
 219
 220   collect_register_by_name (regcache, "orig_eax",
 221                             ((char *) buf) + ORIG_EAX * 4);
 222 }
 223
 224 static void
 225 x86_store_gregset (struct regcache *regcache, const void *buf)
 226 {
 227   int i;
 228
 229 #ifdef __x86_64__
 230   if (register_size (0) == 8)
 231     {
 232       for (i = 0; i < X86_64_NUM_REGS; i++)
 233         if (x86_64_regmap[i] != -1)
 234           supply_register (regcache, i, ((char *) buf) + x86_64_regmap[i]);
 235       return;
 236     }
 237 #endif
 238
 239   for (i = 0; i < I386_NUM_REGS; i++)
 240     supply_register (regcache, i, ((char *) buf) + i386_regmap[i]);
 241
 242   supply_register_by_name (regcache, "orig_eax",
 243                            ((char *) buf) + ORIG_EAX * 4);
 244 }
 245
 246 static void
 247 x86_fill_fpregset (struct regcache *regcache, void *buf)
 248 {
 249 #ifdef __x86_64__
 250   i387_cache_to_fxsave (regcache, buf);
 251 #else
 252   i387_cache_to_fsave (regcache, buf);
 253 #endif
 254 }
 255
 256 static void
 257 x86_store_fpregset (struct regcache *regcache, const void *buf)
 258 {
 259 #ifdef __x86_64__
 260   i387_fxsave_to_cache (regcache, buf);
 261 #else
 262   i387_fsave_to_cache (regcache, buf);
 263 #endif
 264 }
 265
 266 #ifndef __x86_64__
 267
 268 static void
 269 x86_fill_fpxregset (struct regcache *regcache, void *buf)
 270 {
 271   i387_cache_to_fxsave (regcache, buf);
 272 }
 273
 274 static void
 275 x86_store_fpxregset (struct regcache *regcache, const void *buf)
 276 {
 277   i387_fxsave_to_cache (regcache, buf);
 278 }
 279
 280 #endif
 281
 282 static void
 283 x86_fill_xstateregset (struct regcache *regcache, void *buf)
 284 {
 285   i387_cache_to_xsave (regcache, buf);
 286 }
 287
 288 static void
 289 x86_store_xstateregset (struct regcache *regcache, const void *buf)
 290 {
 291   i387_xsave_to_cache (regcache, buf);
 292 }
 293
 294 /* ??? The non-biarch i386 case stores all the i387 regs twice.
 295    Once in i387_.*fsave.* and once in i387_.*fxsave.*.
 296    This is, presumably, to handle the case where PTRACE_[GS]ETFPXREGS
 297    doesn't work.  IWBN to avoid the duplication in the case where it
 298    does work.  Maybe the arch_setup routine could check whether it works
 299    and update target_regsets accordingly, maybe by moving target_regsets
 300    to linux_target_ops and set the right one there, rather than having to
 301    modify the target_regsets global.  */
 302
 303 struct regset_info target_regsets[] =
 304 {
 305 #ifdef HAVE_PTRACE_GETREGS
 306   { PTRACE_GETREGS, PTRACE_SETREGS, 0, sizeof (elf_gregset_t),
 307     GENERAL_REGS,
 308     x86_fill_gregset, x86_store_gregset },
 309   { PTRACE_GETREGSET, PTRACE_SETREGSET, NT_X86_XSTATE, 0,
 310     EXTENDED_REGS, x86_fill_xstateregset, x86_store_xstateregset },
 311 # ifndef __x86_64__
 312 #  ifdef HAVE_PTRACE_GETFPXREGS
 313   { PTRACE_GETFPXREGS, PTRACE_SETFPXREGS, 0, sizeof (elf_fpxregset_t),
 314     EXTENDED_REGS,
 315     x86_fill_fpxregset, x86_store_fpxregset },
 316 #  endif
 317 # endif
 318   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, 0, sizeof (elf_fpregset_t),
 319     FP_REGS,
 320     x86_fill_fpregset, x86_store_fpregset },
 321 #endif /* HAVE_PTRACE_GETREGS */
 322   { 0, 0, 0, -1, -1, NULL, NULL }
 323 };
 324
 325 static CORE_ADDR
 326 x86_get_pc (struct regcache *regcache)
 327 {
 328   int use_64bit = register_size (0) == 8;
 329
 330   if (use_64bit)
 331     {
 332       unsigned long pc;
 333       collect_register_by_name (regcache, "rip", &pc);
 334       return (CORE_ADDR) pc;
 335     }
 336   else
 337     {
 338       unsigned int pc;
 339       collect_register_by_name (regcache, "eip", &pc);
 340       return (CORE_ADDR) pc;
 341     }
 342 }
 343
 344 static void
 345 x86_set_pc (struct regcache *regcache, CORE_ADDR pc)
 346 {
 347   int use_64bit = register_size (0) == 8;
 348
 349   if (use_64bit)
 350     {
 351       unsigned long newpc = pc;
 352       supply_register_by_name (regcache, "rip", &newpc);
 353     }
 354   else
 355     {
 356       unsigned int newpc = pc;
 357       supply_register_by_name (regcache, "eip", &newpc);
 358     }
 359 }
 360 \f
 361 static const unsigned char x86_breakpoint[] = { 0xCC };
 362 #define x86_breakpoint_len 1
 363
 364 static int
 365 x86_breakpoint_at (CORE_ADDR pc)
 366 {
 367   unsigned char c;
 368
 369   (*the_target->read_memory) (pc, &c, 1);
 370   if (c == 0xCC)
 371     return 1;
 372
 373   return 0;
 374 }
 375 \f
 376 /* Support for debug registers.  */
 377
 378 static unsigned long
 379 x86_linux_dr_get (ptid_t ptid, int regnum)
 380 {
 381   int tid;
 382   unsigned long value;
 383
 384   tid = ptid_get_lwp (ptid);
 385
 386   errno = 0;
 387   value = ptrace (PTRACE_PEEKUSER, tid,
 388                   offsetof (struct user, u_debugreg[regnum]), 0);
 389   if (errno != 0)
 390     error ("Couldn't read debug register");
 391
 392   return value;
 393 }
 394
 395 static void
 396 x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
 397 {
 398   int tid;
 399
 400   tid = ptid_get_lwp (ptid);
 401
 402   errno = 0;
 403   ptrace (PTRACE_POKEUSER, tid,
 404           offsetof (struct user, u_debugreg[regnum]), value);
 405   if (errno != 0)
 406     error ("Couldn't write debug register");
 407 }
 408
 409 /* Update the inferior's debug register REGNUM from STATE.  */
 410
 411 void
 412 i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
 413 {
 414   struct inferior_list_entry *lp;
 415   CORE_ADDR addr;
 416   /* Only need to update the threads of this process.  */
 417   int pid = pid_of (get_thread_lwp (current_inferior));
 418
 419   if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
 420     fatal ("Invalid debug register %d", regnum);
 421
 422   addr = state->dr_mirror[regnum];
 423
 424   for (lp = all_lwps.head; lp; lp = lp->next)
 425     {
 426       struct lwp_info *lwp = (struct lwp_info *) lp;
 427
 428       /* The actual update is done later, we just mark that the register
 429          needs updating.  */
 430       if (pid_of (lwp) == pid)
 431         lwp->arch_private->debug_registers_changed = 1;
 432     }
 433 }
 434
 435 /* Update the inferior's DR7 debug control register from STATE.  */
 436
 437 void
 438 i386_dr_low_set_control (const struct i386_debug_reg_state *state)
 439 {
 440   struct inferior_list_entry *lp;
 441   /* Only need to update the threads of this process.  */
 442   int pid = pid_of (get_thread_lwp (current_inferior));
 443
 444   for (lp = all_lwps.head; lp; lp = lp->next)
 445     {
 446       struct lwp_info *lwp = (struct lwp_info *) lp;
 447
 448       /* The actual update is done later, we just mark that the register
 449          needs updating.  */
 450       if (pid_of (lwp) == pid)
 451         lwp->arch_private->debug_registers_changed = 1;
 452     }
 453 }
 454
 455 /* Get the value of the DR6 debug status register from the inferior
 456    and record it in STATE.  */
 457
 458 void
 459 i386_dr_low_get_status (struct i386_debug_reg_state *state)
 460 {
 461   struct lwp_info *lwp = get_thread_lwp (current_inferior);
 462   ptid_t ptid = ptid_of (lwp);
 463
 464   state->dr_status_mirror = x86_linux_dr_get (ptid, DR_STATUS);
 465 }
 466 \f
 467 /* Watchpoint support.  */
 468
 469 static int
 470 x86_insert_point (char type, CORE_ADDR addr, int len)
 471 {
 472   struct process_info *proc = current_process ();
 473   switch (type)
 474     {
 475     case '0':
 476       return set_gdb_breakpoint_at (addr);
 477     case '2':
 478     case '3':
 479     case '4':
 480       return i386_low_insert_watchpoint (&proc->private->arch_private->debug_reg_state,
 481                                          type, addr, len);
 482     default:
 483       /* Unsupported.  */
 484       return 1;
 485     }
 486 }
 487
 488 static int
 489 x86_remove_point (char type, CORE_ADDR addr, int len)
 490 {
 491   struct process_info *proc = current_process ();
 492   switch (type)
 493     {
 494     case '0':
 495       return delete_gdb_breakpoint_at (addr);
 496     case '2':
 497     case '3':
 498     case '4':
 499       return i386_low_remove_watchpoint (&proc->private->arch_private->debug_reg_state,
 500                                          type, addr, len);
 501     default:
 502       /* Unsupported.  */
 503       return 1;
 504     }
 505 }
 506
 507 static int
 508 x86_stopped_by_watchpoint (void)
 509 {
 510   struct process_info *proc = current_process ();
 511   return i386_low_stopped_by_watchpoint (&proc->private->arch_private->debug_reg_state);
 512 }
 513
 514 static CORE_ADDR
 515 x86_stopped_data_address (void)
 516 {
 517   struct process_info *proc = current_process ();
 518   CORE_ADDR addr;
 519   if (i386_low_stopped_data_address (&proc->private->arch_private->debug_reg_state,
 520                                      &addr))
 521     return addr;
 522   return 0;
 523 }
 524 \f
 525 /* Called when a new process is created.  */
 526
 527 static struct arch_process_info *
 528 x86_linux_new_process (void)
 529 {
 530   struct arch_process_info *info = xcalloc (1, sizeof (*info));
 531
 532   i386_low_init_dregs (&info->debug_reg_state);
 533
 534   return info;
 535 }
 536
 537 /* Called when a new thread is detected.  */
 538
 539 static struct arch_lwp_info *
 540 x86_linux_new_thread (void)
 541 {
 542   struct arch_lwp_info *info = xcalloc (1, sizeof (*info));
 543
 544   info->debug_registers_changed = 1;
 545
 546   return info;
 547 }
 548
 549 /* Called when resuming a thread.
 550    If the debug regs have changed, update the thread's copies.  */
 551
 552 static void
 553 x86_linux_prepare_to_resume (struct lwp_info *lwp)
 554 {
 555   ptid_t ptid = ptid_of (lwp);
 556
 557   if (lwp->arch_private->debug_registers_changed)
 558     {
 559       int i;
 560       int pid = ptid_get_pid (ptid);
 561       struct process_info *proc = find_process_pid (pid);
 562       struct i386_debug_reg_state *state = &proc->private->arch_private->debug_reg_state;
 563
 564       for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 565         x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
 566
 567       x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
 568
 569       lwp->arch_private->debug_registers_changed = 0;
 570     }
 571
 572   if (lwp->stopped_by_watchpoint)
 573     x86_linux_dr_set (ptid, DR_STATUS, 0);
 574 }
 575 \f
 576 /* When GDBSERVER is built as a 64-bit application on linux, the
 577    PTRACE_GETSIGINFO data is always presented in 64-bit layout.  Since
 578    debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same
 579    as debugging it with a 32-bit GDBSERVER, we do the 32-bit <-> 64-bit
 580    conversion in-place ourselves.  */
 581
 582 /* These types below (compat_*) define a siginfo type that is layout
 583    compatible with the siginfo type exported by the 32-bit userspace
 584    support.  */
 585
 586 #ifdef __x86_64__
 587
 588 typedef int compat_int_t;
 589 typedef unsigned int compat_uptr_t;
 590
 591 typedef int compat_time_t;
 592 typedef int compat_timer_t;
 593 typedef int compat_clock_t;
 594
 595 struct compat_timeval
 596 {
 597   compat_time_t tv_sec;
 598   int tv_usec;
 599 };
 600
 601 typedef union compat_sigval
 602 {
 603   compat_int_t sival_int;
 604   compat_uptr_t sival_ptr;
 605 } compat_sigval_t;
 606
 607 typedef struct compat_siginfo
 608 {
 609   int si_signo;
 610   int si_errno;
 611   int si_code;
 612
 613   union
 614   {
 615     int _pad[((128 / sizeof (int)) - 3)];
 616
 617     /* kill() */
 618     struct
 619     {
 620       unsigned int _pid;
 621       unsigned int _uid;
 622     } _kill;
 623
 624     /* POSIX.1b timers */
 625     struct
 626     {
 627       compat_timer_t _tid;
 628       int _overrun;
 629       compat_sigval_t _sigval;
 630     } _timer;
 631
 632     /* POSIX.1b signals */
 633     struct
 634     {
 635       unsigned int _pid;
 636       unsigned int _uid;
 637       compat_sigval_t _sigval;
 638     } _rt;
 639
 640     /* SIGCHLD */
 641     struct
 642     {
 643       unsigned int _pid;
 644       unsigned int _uid;
 645       int _status;
 646       compat_clock_t _utime;
 647       compat_clock_t _stime;
 648     } _sigchld;
 649
 650     /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 651     struct
 652     {
 653       unsigned int _addr;
 654     } _sigfault;
 655
 656     /* SIGPOLL */
 657     struct
 658     {
 659       int _band;
 660       int _fd;
 661     } _sigpoll;
 662   } _sifields;
 663 } compat_siginfo_t;
 664
 665 #define cpt_si_pid _sifields._kill._pid
 666 #define cpt_si_uid _sifields._kill._uid
 667 #define cpt_si_timerid _sifields._timer._tid
 668 #define cpt_si_overrun _sifields._timer._overrun
 669 #define cpt_si_status _sifields._sigchld._status
 670 #define cpt_si_utime _sifields._sigchld._utime
 671 #define cpt_si_stime _sifields._sigchld._stime
 672 #define cpt_si_ptr _sifields._rt._sigval.sival_ptr
 673 #define cpt_si_addr _sifields._sigfault._addr
 674 #define cpt_si_band _sifields._sigpoll._band
 675 #define cpt_si_fd _sifields._sigpoll._fd
 676
 677 /* glibc at least up to 2.3.2 doesn't have si_timerid, si_overrun.
 678    In their place is si_timer1,si_timer2.  */
 679 #ifndef si_timerid
 680 #define si_timerid si_timer1
 681 #endif
 682 #ifndef si_overrun
 683 #define si_overrun si_timer2
 684 #endif
 685
 686 static void
 687 compat_siginfo_from_siginfo (compat_siginfo_t *to, siginfo_t *from)
 688 {
 689   memset (to, 0, sizeof (*to));
 690
 691   to->si_signo = from->si_signo;
 692   to->si_errno = from->si_errno;
 693   to->si_code = from->si_code;
 694
 695   if (to->si_code < 0)
 696     {
 697       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 698     }
 699   else if (to->si_code == SI_USER)
 700     {
 701       to->cpt_si_pid = from->si_pid;
 702       to->cpt_si_uid = from->si_uid;
 703     }
 704   else if (to->si_code == SI_TIMER)
 705     {
 706       to->cpt_si_timerid = from->si_timerid;
 707       to->cpt_si_overrun = from->si_overrun;
 708       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 709     }
 710   else
 711     {
 712       switch (to->si_signo)
 713         {
 714         case SIGCHLD:
 715           to->cpt_si_pid = from->si_pid;
 716           to->cpt_si_uid = from->si_uid;
 717           to->cpt_si_status = from->si_status;
 718           to->cpt_si_utime = from->si_utime;
 719           to->cpt_si_stime = from->si_stime;
 720           break;
 721         case SIGILL:
 722         case SIGFPE:
 723         case SIGSEGV:
 724         case SIGBUS:
 725           to->cpt_si_addr = (intptr_t) from->si_addr;
 726           break;
 727         case SIGPOLL:
 728           to->cpt_si_band = from->si_band;
 729           to->cpt_si_fd = from->si_fd;
 730           break;
 731         default:
 732           to->cpt_si_pid = from->si_pid;
 733           to->cpt_si_uid = from->si_uid;
 734           to->cpt_si_ptr = (intptr_t) from->si_ptr;
 735           break;
 736         }
 737     }
 738 }
 739
 740 static void
 741 siginfo_from_compat_siginfo (siginfo_t *to, compat_siginfo_t *from)
 742 {
 743   memset (to, 0, sizeof (*to));
 744
 745   to->si_signo = from->si_signo;
 746   to->si_errno = from->si_errno;
 747   to->si_code = from->si_code;
 748
 749   if (to->si_code < 0)
 750     {
 751       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 752     }
 753   else if (to->si_code == SI_USER)
 754     {
 755       to->si_pid = from->cpt_si_pid;
 756       to->si_uid = from->cpt_si_uid;
 757     }
 758   else if (to->si_code == SI_TIMER)
 759     {
 760       to->si_timerid = from->cpt_si_timerid;
 761       to->si_overrun = from->cpt_si_overrun;
 762       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 763     }
 764   else
 765     {
 766       switch (to->si_signo)
 767         {
 768         case SIGCHLD:
 769           to->si_pid = from->cpt_si_pid;
 770           to->si_uid = from->cpt_si_uid;
 771           to->si_status = from->cpt_si_status;
 772           to->si_utime = from->cpt_si_utime;
 773           to->si_stime = from->cpt_si_stime;
 774           break;
 775         case SIGILL:
 776         case SIGFPE:
 777         case SIGSEGV:
 778         case SIGBUS:
 779           to->si_addr = (void *) (intptr_t) from->cpt_si_addr;
 780           break;
 781         case SIGPOLL:
 782           to->si_band = from->cpt_si_band;
 783           to->si_fd = from->cpt_si_fd;
 784           break;
 785         default:
 786           to->si_pid = from->cpt_si_pid;
 787           to->si_uid = from->cpt_si_uid;
 788           to->si_ptr = (void* ) (intptr_t) from->cpt_si_ptr;
 789           break;
 790         }
 791     }
 792 }
 793
 794 #endif /* __x86_64__ */
 795
 796 /* Convert a native/host siginfo object, into/from the siginfo in the
 797    layout of the inferiors' architecture.  Returns true if any
 798    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 799    from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
 800    INF.  */
 801
 802 static int
 803 x86_siginfo_fixup (struct siginfo *native, void *inf, int direction)
 804 {
 805 #ifdef __x86_64__
 806   /* Is the inferior 32-bit?  If so, then fixup the siginfo object.  */
 807   if (register_size (0) == 4)
 808     {
 809       if (sizeof (struct siginfo) != sizeof (compat_siginfo_t))
 810         fatal ("unexpected difference in siginfo");
 811
 812       if (direction == 0)
 813         compat_siginfo_from_siginfo ((struct compat_siginfo *) inf, native);
 814       else
 815         siginfo_from_compat_siginfo (native, (struct compat_siginfo *) inf);
 816
 817       return 1;
 818     }
 819 #endif
 820
 821   return 0;
 822 }
 823 \f
 824 static int use_xml;
 825
 826 /* Update gdbserver_xmltarget.  */
 827
 828 static void
 829 x86_linux_update_xmltarget (void)
 830 {
 831   static unsigned long long xcr0;
 832   static int have_ptrace_getregset = -1;
 833
 834   if (!current_inferior)
 835     return;
 836
 837 #ifdef __x86_64__
 838   if (num_xmm_registers == 8)
 839     init_registers_i386_linux ();
 840   else
 841     init_registers_amd64_linux ();
 842 #else
 843   init_registers_i386_linux ();
 844 #endif
 845
 846   if (!use_xml)
 847     {
 848       /* Don't use XML.  */
 849 #ifdef __x86_64__
 850       if (num_xmm_registers == 8)
 851         gdbserver_xmltarget = xmltarget_i386_linux_no_xml;
 852       else
 853         gdbserver_xmltarget = xmltarget_amd64_linux_no_xml;
 854 #else
 855       gdbserver_xmltarget = xmltarget_i386_linux_no_xml;
 856 #endif
 857
 858       x86_xcr0 = I386_XSTATE_SSE_MASK;
 859
 860       return;
 861     }
 862
 863   /* Check if XSAVE extended state is supported.  */
 864   if (have_ptrace_getregset == -1)
 865     {
 866       int pid = pid_of (get_thread_lwp (current_inferior));
 867       unsigned long long xstateregs[I386_XSTATE_SSE_SIZE / sizeof (long long)];
 868       struct iovec iov;
 869       struct regset_info *regset;
 870
 871       iov.iov_base = xstateregs;
 872       iov.iov_len = sizeof (xstateregs);
 873
 874       /* Check if PTRACE_GETREGSET works.  */
 875       if (ptrace (PTRACE_GETREGSET, pid, (unsigned int) NT_X86_XSTATE,
 876                   &iov) < 0)
 877         {
 878           have_ptrace_getregset = 0;
 879           return;
 880         }
 881       else
 882         have_ptrace_getregset = 1;
 883
 884       /* Get XCR0 from XSAVE extended state at byte 464.  */
 885       xcr0 = xstateregs[464 / sizeof (long long)];
 886
 887       /* Use PTRACE_GETREGSET if it is available.  */
 888       for (regset = target_regsets;
 889            regset->fill_function != NULL; regset++)
 890         if (regset->get_request == PTRACE_GETREGSET)
 891           regset->size = I386_XSTATE_SIZE (xcr0);
 892         else if (regset->type != GENERAL_REGS)
 893           regset->size = 0;
 894     }
 895
 896   if (have_ptrace_getregset)
 897     {
 898       /* AVX is the highest feature we support.  */
 899       if ((xcr0 & I386_XSTATE_AVX_MASK) == I386_XSTATE_AVX_MASK)
 900         {
 901           x86_xcr0 = xcr0;
 902
 903 #ifdef __x86_64__
 904           /* I386 has 8 xmm regs.  */
 905           if (num_xmm_registers == 8)
 906             init_registers_i386_avx_linux ();
 907           else
 908             init_registers_amd64_avx_linux ();
 909 #else
 910           init_registers_i386_avx_linux ();
 911 #endif
 912         }
 913     }
 914 }
 915
 916 /* Process qSupported query, "xmlRegisters=".  Update the buffer size for
 917    PTRACE_GETREGSET.  */
 918
 919 static void
 920 x86_linux_process_qsupported (const char *query)
 921 {
 922   /* Return if gdb doesn't support XML.  If gdb sends "xmlRegisters="
 923      with "i386" in qSupported query, it supports x86 XML target
 924      descriptions.  */
 925   use_xml = 0;
 926   if (query != NULL && strncmp (query, "xmlRegisters=", 13) == 0)
 927     {
 928       char *copy = xstrdup (query + 13);
 929       char *p;
 930
 931       for (p = strtok (copy, ","); p != NULL; p = strtok (NULL, ","))
 932         {
 933           if (strcmp (p, "i386") == 0)
 934             {
 935               use_xml = 1;
 936               break;
 937             }
 938         }
 939
 940       free (copy);
 941     }
 942
 943   x86_linux_update_xmltarget ();
 944 }
 945
 946 /* Initialize gdbserver for the architecture of the inferior.  */
 947
 948 static void
 949 x86_arch_setup (void)
 950 {
 951 #ifdef __x86_64__
 952   int pid = pid_of (get_thread_lwp (current_inferior));
 953   char *file = linux_child_pid_to_exec_file (pid);
 954   int use_64bit = elf_64_file_p (file);
 955
 956   free (file);
 957
 958   if (use_64bit < 0)
 959     {
 960       /* This can only happen if /proc/<pid>/exe is unreadable,
 961          but "that can't happen" if we've gotten this far.
 962          Fall through and assume this is a 32-bit program.  */
 963     }
 964   else if (use_64bit)
 965     {
 966       /* Amd64 doesn't have HAVE_LINUX_USRREGS.  */
 967       the_low_target.num_regs = -1;
 968       the_low_target.regmap = NULL;
 969       the_low_target.cannot_fetch_register = NULL;
 970       the_low_target.cannot_store_register = NULL;
 971
 972       /* Amd64 has 16 xmm regs.  */
 973       num_xmm_registers = 16;
 974
 975       x86_linux_update_xmltarget ();
 976       return;
 977     }
 978 #endif
 979
 980   /* Ok we have a 32-bit inferior.  */
 981
 982   the_low_target.num_regs = I386_NUM_REGS;
 983   the_low_target.regmap = i386_regmap;
 984   the_low_target.cannot_fetch_register = i386_cannot_fetch_register;
 985   the_low_target.cannot_store_register = i386_cannot_store_register;
 986
 987   /* I386 has 8 xmm regs.  */
 988   num_xmm_registers = 8;
 989
 990   x86_linux_update_xmltarget ();
 991 }
 992
 993 /* This is initialized assuming an amd64 target.
 994    x86_arch_setup will correct it for i386 or amd64 targets.  */
 995
 996 struct linux_target_ops the_low_target =
 997 {
 998   x86_arch_setup,
 999   -1,
1000   NULL,
1001   NULL,
1002   NULL,
1003   x86_get_pc,
1004   x86_set_pc,
1005   x86_breakpoint,
1006   x86_breakpoint_len,
1007   NULL,
1008   1,
1009   x86_breakpoint_at,
1010   x86_insert_point,
1011   x86_remove_point,
1012   x86_stopped_by_watchpoint,
1013   x86_stopped_data_address,
1014   /* collect_ptrace_register/supply_ptrace_register are not needed in the
1015      native i386 case (no registers smaller than an xfer unit), and are not
1016      used in the biarch case (HAVE_LINUX_USRREGS is not defined).  */
1017   NULL,
1018   NULL,
1019   /* need to fix up i386 siginfo if host is amd64 */
1020   x86_siginfo_fixup,
1021   x86_linux_new_process,
1022   x86_linux_new_thread,
1023   x86_linux_prepare_to_resume,
1024   x86_linux_process_qsupported
1025 };