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