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
   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
  28 #include "gdb_proc_service.h"
  29
  30 /* NOTE: gdb_proc_service.h may include linux/elf.h.
  31    We need Elf32_Phdr.  If we don't get linux/elf.h we could include
  32    elf.h like linux-ppc-low.c does.  */
  33
  34 /* Defined in auto-generated file reg-i386-linux.c.  */
  35 void init_registers_i386_linux (void);
  36 /* Defined in auto-generated file reg-x86-64-linux.c.  */
  37 void init_registers_x86_64_linux (void);
  38
  39 #include <sys/reg.h>
  40 #include <sys/procfs.h>
  41 #include <sys/ptrace.h>
  42
  43 #ifndef PTRACE_GET_THREAD_AREA
  44 #define PTRACE_GET_THREAD_AREA 25
  45 #endif
  46
  47 /* This definition comes from prctl.h, but some kernels may not have it.  */
  48 #ifndef PTRACE_ARCH_PRCTL
  49 #define PTRACE_ARCH_PRCTL      30
  50 #endif
  51
  52 /* The following definitions come from prctl.h, but may be absent
  53    for certain configurations.  */
  54 #ifndef ARCH_GET_FS
  55 #define ARCH_SET_GS 0x1001
  56 #define ARCH_SET_FS 0x1002
  57 #define ARCH_GET_FS 0x1003
  58 #define ARCH_GET_GS 0x1004
  59 #endif
  60
  61 /* Per-process arch-specific data we want to keep.  */
  62
  63 struct arch_process_info
  64 {
  65   struct i386_debug_reg_state debug_reg_state;
  66 };
  67
  68 /* Per-thread arch-specific data we want to keep.  */
  69
  70 struct arch_lwp_info
  71 {
  72   /* Non-zero if our copy differs from what's recorded in the thread.  */
  73   int debug_registers_changed;
  74 };
  75
  76 #ifdef __x86_64__
  77
  78 /* Mapping between the general-purpose registers in `struct user'
  79    format and GDB's register array layout.
  80    Note that the transfer layout uses 64-bit regs.  */
  81 static /*const*/ int i386_regmap[] =
  82 {
  83   RAX * 8, RCX * 8, RDX * 8, RBX * 8,
  84   RSP * 8, RBP * 8, RSI * 8, RDI * 8,
  85   RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
  86   DS * 8, ES * 8, FS * 8, GS * 8
  87 };
  88
  89 #define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
  90
  91 /* So code below doesn't have to care, i386 or amd64.  */
  92 #define ORIG_EAX ORIG_RAX
  93
  94 static const int x86_64_regmap[] =
  95 {
  96   RAX * 8, RBX * 8, RCX * 8, RDX * 8,
  97   RSI * 8, RDI * 8, RBP * 8, RSP * 8,
  98   R8 * 8, R9 * 8, R10 * 8, R11 * 8,
  99   R12 * 8, R13 * 8, R14 * 8, R15 * 8,
 100   RIP * 8, EFLAGS * 8, CS * 8, SS * 8,
 101   DS * 8, ES * 8, FS * 8, GS * 8,
 102   -1, -1, -1, -1, -1, -1, -1, -1,
 103   -1, -1, -1, -1, -1, -1, -1, -1,
 104   -1, -1, -1, -1, -1, -1, -1, -1,
 105   -1, -1, -1, -1, -1, -1, -1, -1, -1,
 106   ORIG_RAX * 8
 107 };
 108
 109 #define X86_64_NUM_REGS (sizeof (x86_64_regmap) / sizeof (x86_64_regmap[0]))
 110
 111 #else /* ! __x86_64__ */
 112
 113 /* Mapping between the general-purpose registers in `struct user'
 114    format and GDB's register array layout.  */
 115 static /*const*/ int i386_regmap[] =
 116 {
 117   EAX * 4, ECX * 4, EDX * 4, EBX * 4,
 118   UESP * 4, EBP * 4, ESI * 4, EDI * 4,
 119   EIP * 4, EFL * 4, CS * 4, SS * 4,
 120   DS * 4, ES * 4, FS * 4, GS * 4
 121 };
 122
 123 #define I386_NUM_REGS (sizeof (i386_regmap) / sizeof (i386_regmap[0]))
 124
 125 #endif
 126 \f
 127 /* Called by libthread_db.  */
 128
 129 ps_err_e
 130 ps_get_thread_area (const struct ps_prochandle *ph,
 131                     lwpid_t lwpid, int idx, void **base)
 132 {
 133 #ifdef __x86_64__
 134   int use_64bit = register_size (0) == 8;
 135
 136   if (use_64bit)
 137     {
 138       switch (idx)
 139         {
 140         case FS:
 141           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 142             return PS_OK;
 143           break;
 144         case GS:
 145           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 146             return PS_OK;
 147           break;
 148         default:
 149           return PS_BADADDR;
 150         }
 151       return PS_ERR;
 152     }
 153 #endif
 154
 155   {
 156     unsigned int desc[4];
 157
 158     if (ptrace (PTRACE_GET_THREAD_AREA, lwpid,
 159                 (void *) (intptr_t) idx, (unsigned long) &desc) < 0)
 160       return PS_ERR;
 161
 162     *(int *)base = desc[1];
 163     return PS_OK;
 164   }
 165 }
 166 \f
 167 static int
 168 i386_cannot_store_register (int regno)
 169 {
 170   return regno >= I386_NUM_REGS;
 171 }
 172
 173 static int
 174 i386_cannot_fetch_register (int regno)
 175 {
 176   return regno >= I386_NUM_REGS;
 177 }
 178
 179 static void
 180 x86_fill_gregset (void *buf)
 181 {
 182   int i;
 183
 184 #ifdef __x86_64__
 185   if (register_size (0) == 8)
 186     {
 187       for (i = 0; i < X86_64_NUM_REGS; i++)
 188         if (x86_64_regmap[i] != -1)
 189           collect_register (i, ((char *) buf) + x86_64_regmap[i]);
 190       return;
 191     }
 192 #endif
 193
 194   for (i = 0; i < I386_NUM_REGS; i++)
 195     collect_register (i, ((char *) buf) + i386_regmap[i]);
 196
 197   collect_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
 198 }
 199
 200 static void
 201 x86_store_gregset (const void *buf)
 202 {
 203   int i;
 204
 205 #ifdef __x86_64__
 206   if (register_size (0) == 8)
 207     {
 208       for (i = 0; i < X86_64_NUM_REGS; i++)
 209         if (x86_64_regmap[i] != -1)
 210           supply_register (i, ((char *) buf) + x86_64_regmap[i]);
 211       return;
 212     }
 213 #endif
 214
 215   for (i = 0; i < I386_NUM_REGS; i++)
 216     supply_register (i, ((char *) buf) + i386_regmap[i]);
 217
 218   supply_register_by_name ("orig_eax", ((char *) buf) + ORIG_EAX * 4);
 219 }
 220
 221 static void
 222 x86_fill_fpregset (void *buf)
 223 {
 224 #ifdef __x86_64__
 225   i387_cache_to_fxsave (buf);
 226 #else
 227   i387_cache_to_fsave (buf);
 228 #endif
 229 }
 230
 231 static void
 232 x86_store_fpregset (const void *buf)
 233 {
 234 #ifdef __x86_64__
 235   i387_fxsave_to_cache (buf);
 236 #else
 237   i387_fsave_to_cache (buf);
 238 #endif
 239 }
 240
 241 #ifndef __x86_64__
 242
 243 static void
 244 x86_fill_fpxregset (void *buf)
 245 {
 246   i387_cache_to_fxsave (buf);
 247 }
 248
 249 static void
 250 x86_store_fpxregset (const void *buf)
 251 {
 252   i387_fxsave_to_cache (buf);
 253 }
 254
 255 #endif
 256
 257 /* ??? The non-biarch i386 case stores all the i387 regs twice.
 258    Once in i387_.*fsave.* and once in i387_.*fxsave.*.
 259    This is, presumably, to handle the case where PTRACE_[GS]ETFPXREGS
 260    doesn't work.  IWBN to avoid the duplication in the case where it
 261    does work.  Maybe the arch_setup routine could check whether it works
 262    and update target_regsets accordingly, maybe by moving target_regsets
 263    to linux_target_ops and set the right one there, rather than having to
 264    modify the target_regsets global.  */
 265
 266 struct regset_info target_regsets[] =
 267 {
 268 #ifdef HAVE_PTRACE_GETREGS
 269   { PTRACE_GETREGS, PTRACE_SETREGS, sizeof (elf_gregset_t),
 270     GENERAL_REGS,
 271     x86_fill_gregset, x86_store_gregset },
 272 # ifndef __x86_64__
 273 #  ifdef HAVE_PTRACE_GETFPXREGS
 274   { PTRACE_GETFPXREGS, PTRACE_SETFPXREGS, sizeof (elf_fpxregset_t),
 275     EXTENDED_REGS,
 276     x86_fill_fpxregset, x86_store_fpxregset },
 277 #  endif
 278 # endif
 279   { PTRACE_GETFPREGS, PTRACE_SETFPREGS, sizeof (elf_fpregset_t),
 280     FP_REGS,
 281     x86_fill_fpregset, x86_store_fpregset },
 282 #endif /* HAVE_PTRACE_GETREGS */
 283   { 0, 0, -1, -1, NULL, NULL }
 284 };
 285
 286 static CORE_ADDR
 287 x86_get_pc (void)
 288 {
 289   int use_64bit = register_size (0) == 8;
 290
 291   if (use_64bit)
 292     {
 293       unsigned long pc;
 294       collect_register_by_name ("rip", &pc);
 295       return (CORE_ADDR) pc;
 296     }
 297   else
 298     {
 299       unsigned int pc;
 300       collect_register_by_name ("eip", &pc);
 301       return (CORE_ADDR) pc;
 302     }
 303 }
 304
 305 static void
 306 x86_set_pc (CORE_ADDR pc)
 307 {
 308   int use_64bit = register_size (0) == 8;
 309
 310   if (use_64bit)
 311     {
 312       unsigned long newpc = pc;
 313       supply_register_by_name ("rip", &newpc);
 314     }
 315   else
 316     {
 317       unsigned int newpc = pc;
 318       supply_register_by_name ("eip", &newpc);
 319     }
 320 }
 321 \f
 322 static const unsigned char x86_breakpoint[] = { 0xCC };
 323 #define x86_breakpoint_len 1
 324
 325 static int
 326 x86_breakpoint_at (CORE_ADDR pc)
 327 {
 328   unsigned char c;
 329
 330   read_inferior_memory (pc, &c, 1);
 331   if (c == 0xCC)
 332     return 1;
 333
 334   return 0;
 335 }
 336 \f
 337 /* Support for debug registers.  */
 338
 339 static unsigned long
 340 x86_linux_dr_get (ptid_t ptid, int regnum)
 341 {
 342   int tid;
 343   unsigned long value;
 344
 345   tid = ptid_get_lwp (ptid);
 346
 347   errno = 0;
 348   value = ptrace (PTRACE_PEEKUSER, tid,
 349                   offsetof (struct user, u_debugreg[regnum]), 0);
 350   if (errno != 0)
 351     error ("Couldn't read debug register");
 352
 353   return value;
 354 }
 355
 356 static void
 357 x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
 358 {
 359   int tid;
 360
 361   tid = ptid_get_lwp (ptid);
 362
 363   errno = 0;
 364   ptrace (PTRACE_POKEUSER, tid,
 365           offsetof (struct user, u_debugreg[regnum]), value);
 366   if (errno != 0)
 367     error ("Couldn't write debug register");
 368 }
 369
 370 /* Update the inferior's debug register REGNUM from STATE.  */
 371
 372 void
 373 i386_dr_low_set_addr (const struct i386_debug_reg_state *state, int regnum)
 374 {
 375   struct inferior_list_entry *lp;
 376   CORE_ADDR addr;
 377   /* Only need to update the threads of this process.  */
 378   int pid = pid_of (get_thread_lwp (current_inferior));
 379
 380   if (! (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR))
 381     fatal ("Invalid debug register %d", regnum);
 382
 383   addr = state->dr_mirror[regnum];
 384
 385   for (lp = all_lwps.head; lp; lp = lp->next)
 386     {
 387       struct lwp_info *lwp = (struct lwp_info *) lp;
 388
 389       /* The actual update is done later, we just mark that the register
 390          needs updating.  */
 391       if (pid_of (lwp) == pid)
 392         lwp->arch_private->debug_registers_changed = 1;
 393     }
 394 }
 395
 396 /* Update the inferior's DR7 debug control register from STATE.  */
 397
 398 void
 399 i386_dr_low_set_control (const struct i386_debug_reg_state *state)
 400 {
 401   struct inferior_list_entry *lp;
 402   /* Only need to update the threads of this process.  */
 403   int pid = pid_of (get_thread_lwp (current_inferior));
 404
 405   for (lp = all_lwps.head; lp; lp = lp->next)
 406     {
 407       struct lwp_info *lwp = (struct lwp_info *) lp;
 408
 409       /* The actual update is done later, we just mark that the register
 410          needs updating.  */
 411       if (pid_of (lwp) == pid)
 412         lwp->arch_private->debug_registers_changed = 1;
 413     }
 414 }
 415
 416 /* Get the value of the DR6 debug status register from the inferior
 417    and record it in STATE.  */
 418
 419 void
 420 i386_dr_low_get_status (struct i386_debug_reg_state *state)
 421 {
 422   struct lwp_info *lwp = get_thread_lwp (current_inferior);
 423   ptid_t ptid = ptid_of (lwp);
 424
 425   state->dr_status_mirror = x86_linux_dr_get (ptid, DR_STATUS);
 426 }
 427 \f
 428 /* Watchpoint support.  */
 429
 430 static int
 431 x86_insert_point (char type, CORE_ADDR addr, int len)
 432 {
 433   struct process_info *proc = current_process ();
 434   switch (type)
 435     {
 436     case '2':
 437     case '3':
 438     case '4':
 439       return i386_low_insert_watchpoint (&proc->private->arch_private->debug_reg_state,
 440                                          type, addr, len);
 441     default:
 442       /* Unsupported.  */
 443       return 1;
 444     }
 445 }
 446
 447 static int
 448 x86_remove_point (char type, CORE_ADDR addr, int len)
 449 {
 450   struct process_info *proc = current_process ();
 451   switch (type)
 452     {
 453     case '2':
 454     case '3':
 455     case '4':
 456       return i386_low_remove_watchpoint (&proc->private->arch_private->debug_reg_state,
 457                                          type, addr, len);
 458     default:
 459       /* Unsupported.  */
 460       return 1;
 461     }
 462 }
 463
 464 static int
 465 x86_stopped_by_watchpoint (void)
 466 {
 467   struct process_info *proc = current_process ();
 468   return i386_low_stopped_by_watchpoint (&proc->private->arch_private->debug_reg_state);
 469 }
 470
 471 static CORE_ADDR
 472 x86_stopped_data_address (void)
 473 {
 474   struct process_info *proc = current_process ();
 475   CORE_ADDR addr;
 476   if (i386_low_stopped_data_address (&proc->private->arch_private->debug_reg_state,
 477                                      &addr))
 478     return addr;
 479   return 0;
 480 }
 481 \f
 482 /* Called when a new process is created.  */
 483
 484 static struct arch_process_info *
 485 x86_linux_new_process (void)
 486 {
 487   struct arch_process_info *info = xcalloc (1, sizeof (*info));
 488
 489   i386_low_init_dregs (&info->debug_reg_state);
 490
 491   return info;
 492 }
 493
 494 /* Called when a new thread is detected.  */
 495
 496 static struct arch_lwp_info *
 497 x86_linux_new_thread (void)
 498 {
 499   struct arch_lwp_info *info = xcalloc (1, sizeof (*info));
 500
 501   info->debug_registers_changed = 1;
 502
 503   return info;
 504 }
 505
 506 /* Called when resuming a thread.
 507    If the debug regs have changed, update the thread's copies.  */
 508
 509 static void
 510 x86_linux_prepare_to_resume (struct lwp_info *lwp)
 511 {
 512   if (lwp->arch_private->debug_registers_changed)
 513     {
 514       int i;
 515       ptid_t ptid = ptid_of (lwp);
 516       int pid = ptid_get_pid (ptid);
 517       struct process_info *proc = find_process_pid (pid);
 518       struct i386_debug_reg_state *state = &proc->private->arch_private->debug_reg_state;
 519
 520       for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 521         x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
 522
 523       x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
 524
 525       lwp->arch_private->debug_registers_changed = 0;
 526     }
 527 }
 528 \f
 529 /* When GDBSERVER is built as a 64-bit application on linux, the
 530    PTRACE_GETSIGINFO data is always presented in 64-bit layout.  Since
 531    debugging a 32-bit inferior with a 64-bit GDBSERVER should look the same
 532    as debugging it with a 32-bit GDBSERVER, we do the 32-bit <-> 64-bit
 533    conversion in-place ourselves.  */
 534
 535 /* These types below (compat_*) define a siginfo type that is layout
 536    compatible with the siginfo type exported by the 32-bit userspace
 537    support.  */
 538
 539 #ifdef __x86_64__
 540
 541 typedef int compat_int_t;
 542 typedef unsigned int compat_uptr_t;
 543
 544 typedef int compat_time_t;
 545 typedef int compat_timer_t;
 546 typedef int compat_clock_t;
 547
 548 struct compat_timeval
 549 {
 550   compat_time_t tv_sec;
 551   int tv_usec;
 552 };
 553
 554 typedef union compat_sigval
 555 {
 556   compat_int_t sival_int;
 557   compat_uptr_t sival_ptr;
 558 } compat_sigval_t;
 559
 560 typedef struct compat_siginfo
 561 {
 562   int si_signo;
 563   int si_errno;
 564   int si_code;
 565
 566   union
 567   {
 568     int _pad[((128 / sizeof (int)) - 3)];
 569
 570     /* kill() */
 571     struct
 572     {
 573       unsigned int _pid;
 574       unsigned int _uid;
 575     } _kill;
 576
 577     /* POSIX.1b timers */
 578     struct
 579     {
 580       compat_timer_t _tid;
 581       int _overrun;
 582       compat_sigval_t _sigval;
 583     } _timer;
 584
 585     /* POSIX.1b signals */
 586     struct
 587     {
 588       unsigned int _pid;
 589       unsigned int _uid;
 590       compat_sigval_t _sigval;
 591     } _rt;
 592
 593     /* SIGCHLD */
 594     struct
 595     {
 596       unsigned int _pid;
 597       unsigned int _uid;
 598       int _status;
 599       compat_clock_t _utime;
 600       compat_clock_t _stime;
 601     } _sigchld;
 602
 603     /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 604     struct
 605     {
 606       unsigned int _addr;
 607     } _sigfault;
 608
 609     /* SIGPOLL */
 610     struct
 611     {
 612       int _band;
 613       int _fd;
 614     } _sigpoll;
 615   } _sifields;
 616 } compat_siginfo_t;
 617
 618 #define cpt_si_pid _sifields._kill._pid
 619 #define cpt_si_uid _sifields._kill._uid
 620 #define cpt_si_timerid _sifields._timer._tid
 621 #define cpt_si_overrun _sifields._timer._overrun
 622 #define cpt_si_status _sifields._sigchld._status
 623 #define cpt_si_utime _sifields._sigchld._utime
 624 #define cpt_si_stime _sifields._sigchld._stime
 625 #define cpt_si_ptr _sifields._rt._sigval.sival_ptr
 626 #define cpt_si_addr _sifields._sigfault._addr
 627 #define cpt_si_band _sifields._sigpoll._band
 628 #define cpt_si_fd _sifields._sigpoll._fd
 629
 630 /* glibc at least up to 2.3.2 doesn't have si_timerid, si_overrun.
 631    In their place is si_timer1,si_timer2.  */
 632 #ifndef si_timerid
 633 #define si_timerid si_timer1
 634 #endif
 635 #ifndef si_overrun
 636 #define si_overrun si_timer2
 637 #endif
 638
 639 static void
 640 compat_siginfo_from_siginfo (compat_siginfo_t *to, siginfo_t *from)
 641 {
 642   memset (to, 0, sizeof (*to));
 643
 644   to->si_signo = from->si_signo;
 645   to->si_errno = from->si_errno;
 646   to->si_code = from->si_code;
 647
 648   if (to->si_code < 0)
 649     {
 650       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 651     }
 652   else if (to->si_code == SI_USER)
 653     {
 654       to->cpt_si_pid = from->si_pid;
 655       to->cpt_si_uid = from->si_uid;
 656     }
 657   else if (to->si_code == SI_TIMER)
 658     {
 659       to->cpt_si_timerid = from->si_timerid;
 660       to->cpt_si_overrun = from->si_overrun;
 661       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 662     }
 663   else
 664     {
 665       switch (to->si_signo)
 666         {
 667         case SIGCHLD:
 668           to->cpt_si_pid = from->si_pid;
 669           to->cpt_si_uid = from->si_uid;
 670           to->cpt_si_status = from->si_status;
 671           to->cpt_si_utime = from->si_utime;
 672           to->cpt_si_stime = from->si_stime;
 673           break;
 674         case SIGILL:
 675         case SIGFPE:
 676         case SIGSEGV:
 677         case SIGBUS:
 678           to->cpt_si_addr = (intptr_t) from->si_addr;
 679           break;
 680         case SIGPOLL:
 681           to->cpt_si_band = from->si_band;
 682           to->cpt_si_fd = from->si_fd;
 683           break;
 684         default:
 685           to->cpt_si_pid = from->si_pid;
 686           to->cpt_si_uid = from->si_uid;
 687           to->cpt_si_ptr = (intptr_t) from->si_ptr;
 688           break;
 689         }
 690     }
 691 }
 692
 693 static void
 694 siginfo_from_compat_siginfo (siginfo_t *to, compat_siginfo_t *from)
 695 {
 696   memset (to, 0, sizeof (*to));
 697
 698   to->si_signo = from->si_signo;
 699   to->si_errno = from->si_errno;
 700   to->si_code = from->si_code;
 701
 702   if (to->si_code < 0)
 703     {
 704       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 705     }
 706   else if (to->si_code == SI_USER)
 707     {
 708       to->si_pid = from->cpt_si_pid;
 709       to->si_uid = from->cpt_si_uid;
 710     }
 711   else if (to->si_code == SI_TIMER)
 712     {
 713       to->si_timerid = from->cpt_si_timerid;
 714       to->si_overrun = from->cpt_si_overrun;
 715       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 716     }
 717   else
 718     {
 719       switch (to->si_signo)
 720         {
 721         case SIGCHLD:
 722           to->si_pid = from->cpt_si_pid;
 723           to->si_uid = from->cpt_si_uid;
 724           to->si_status = from->cpt_si_status;
 725           to->si_utime = from->cpt_si_utime;
 726           to->si_stime = from->cpt_si_stime;
 727           break;
 728         case SIGILL:
 729         case SIGFPE:
 730         case SIGSEGV:
 731         case SIGBUS:
 732           to->si_addr = (void *) (intptr_t) from->cpt_si_addr;
 733           break;
 734         case SIGPOLL:
 735           to->si_band = from->cpt_si_band;
 736           to->si_fd = from->cpt_si_fd;
 737           break;
 738         default:
 739           to->si_pid = from->cpt_si_pid;
 740           to->si_uid = from->cpt_si_uid;
 741           to->si_ptr = (void* ) (intptr_t) from->cpt_si_ptr;
 742           break;
 743         }
 744     }
 745 }
 746
 747 #endif /* __x86_64__ */
 748
 749 /* Convert a native/host siginfo object, into/from the siginfo in the
 750    layout of the inferiors' architecture.  Returns true if any
 751    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 752    from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
 753    INF.  */
 754
 755 static int
 756 x86_siginfo_fixup (struct siginfo *native, void *inf, int direction)
 757 {
 758 #ifdef __x86_64__
 759   /* Is the inferior 32-bit?  If so, then fixup the siginfo object.  */
 760   if (register_size (0) == 4)
 761     {
 762       if (sizeof (struct siginfo) != sizeof (compat_siginfo_t))
 763         fatal ("unexpected difference in siginfo");
 764
 765       if (direction == 0)
 766         compat_siginfo_from_siginfo ((struct compat_siginfo *) inf, native);
 767       else
 768         siginfo_from_compat_siginfo (native, (struct compat_siginfo *) inf);
 769
 770       return 1;
 771     }
 772 #endif
 773
 774   return 0;
 775 }
 776 \f
 777 /* Initialize gdbserver for the architecture of the inferior.  */
 778
 779 static void
 780 x86_arch_setup (void)
 781 {
 782 #ifdef __x86_64__
 783   int pid = pid_of (get_thread_lwp (current_inferior));
 784   char *file = linux_child_pid_to_exec_file (pid);
 785   int use_64bit = elf_64_file_p (file);
 786
 787   free (file);
 788
 789   if (use_64bit < 0)
 790     {
 791       /* This can only happen if /proc/<pid>/exe is unreadable,
 792          but "that can't happen" if we've gotten this far.
 793          Fall through and assume this is a 32-bit program.  */
 794     }
 795   else if (use_64bit)
 796     {
 797       init_registers_x86_64_linux ();
 798
 799       /* Amd64 doesn't have HAVE_LINUX_USRREGS.  */
 800       the_low_target.num_regs = -1;
 801       the_low_target.regmap = NULL;
 802       the_low_target.cannot_fetch_register = NULL;
 803       the_low_target.cannot_store_register = NULL;
 804
 805       /* Amd64 has 16 xmm regs.  */
 806       num_xmm_registers = 16;
 807
 808       return;
 809     }
 810 #endif
 811
 812   /* Ok we have a 32-bit inferior.  */
 813
 814   init_registers_i386_linux ();
 815
 816   the_low_target.num_regs = I386_NUM_REGS;
 817   the_low_target.regmap = i386_regmap;
 818   the_low_target.cannot_fetch_register = i386_cannot_fetch_register;
 819   the_low_target.cannot_store_register = i386_cannot_store_register;
 820
 821   /* I386 has 8 xmm regs.  */
 822   num_xmm_registers = 8;
 823 }
 824
 825 /* This is initialized assuming an amd64 target.
 826    x86_arch_setup will correct it for i386 or amd64 targets.  */
 827
 828 struct linux_target_ops the_low_target =
 829 {
 830   x86_arch_setup,
 831   -1,
 832   NULL,
 833   NULL,
 834   NULL,
 835   x86_get_pc,
 836   x86_set_pc,
 837   x86_breakpoint,
 838   x86_breakpoint_len,
 839   NULL,
 840   1,
 841   x86_breakpoint_at,
 842   x86_insert_point,
 843   x86_remove_point,
 844   x86_stopped_by_watchpoint,
 845   x86_stopped_data_address,
 846   /* collect_ptrace_register/supply_ptrace_register are not needed in the
 847      native i386 case (no registers smaller than an xfer unit), and are not
 848      used in the biarch case (HAVE_LINUX_USRREGS is not defined).  */
 849   NULL,
 850   NULL,
 851   /* need to fix up i386 siginfo if host is amd64 */
 852   x86_siginfo_fixup,
 853   x86_linux_new_process,
 854   x86_linux_new_thread,
 855   x86_linux_prepare_to_resume
 856 };