gdb/amd64-linux-nat.c

   1 /* Native-dependent code for GNU/Linux x86-64.
   2
   3    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   4    2011 Free Software Foundation, Inc.
   5    Contributed by Jiri Smid, SuSE Labs.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "regset.h"
  27 #include "linux-nat.h"
  28 #include "amd64-linux-tdep.h"
  29
  30 #include "gdb_assert.h"
  31 #include "gdb_string.h"
  32 #include "elf/common.h"
  33 #include <sys/uio.h>
  34 #include <sys/ptrace.h>
  35 #include <sys/debugreg.h>
  36 #include <sys/syscall.h>
  37 #include <sys/procfs.h>
  38 #include <asm/prctl.h>
  39 /* FIXME ezannoni-2003-07-09: we need <sys/reg.h> to be included after
  40    <asm/ptrace.h> because the latter redefines FS and GS for no apparent
  41    reason, and those definitions don't match the ones that libpthread_db
  42    uses, which come from <sys/reg.h>.  */
  43 /* ezannoni-2003-07-09: I think this is fixed.  The extraneous defs have
  44    been removed from ptrace.h in the kernel.  However, better safe than
  45    sorry.  */
  46 #include <asm/ptrace.h>
  47 #include <sys/reg.h>
  48 #include "gdb_proc_service.h"
  49
  50 /* Prototypes for supply_gregset etc.  */
  51 #include "gregset.h"
  52
  53 #include "amd64-tdep.h"
  54 #include "i386-linux-tdep.h"
  55 #include "amd64-nat.h"
  56 #include "i386-nat.h"
  57 #include "i386-xstate.h"
  58
  59 #ifndef PTRACE_GETREGSET
  60 #define PTRACE_GETREGSET        0x4204
  61 #endif
  62
  63 #ifndef PTRACE_SETREGSET
  64 #define PTRACE_SETREGSET        0x4205
  65 #endif
  66
  67 /* Per-thread arch-specific data we want to keep.  */
  68
  69 struct arch_lwp_info
  70 {
  71   /* Non-zero if our copy differs from what's recorded in the thread.  */
  72   int debug_registers_changed;
  73 };
  74
  75 /* Does the current host support PTRACE_GETREGSET?  */
  76 static int have_ptrace_getregset = -1;
  77
  78 /* Mapping between the general-purpose registers in GNU/Linux x86-64
  79    `struct user' format and GDB's register cache layout for GNU/Linux
  80    i386.
  81
  82    Note that most GNU/Linux x86-64 registers are 64-bit, while the
  83    GNU/Linux i386 registers are all 32-bit, but since we're
  84    little-endian we get away with that.  */
  85
  86 /* From <sys/reg.h> on GNU/Linux i386.  */
  87 static int amd64_linux_gregset32_reg_offset[] =
  88 {
  89   RAX * 8, RCX * 8,             /* %eax, %ecx */
  90   RDX * 8, RBX * 8,             /* %edx, %ebx */
  91   RSP * 8, RBP * 8,             /* %esp, %ebp */
  92   RSI * 8, RDI * 8,             /* %esi, %edi */
  93   RIP * 8, EFLAGS * 8,          /* %eip, %eflags */
  94   CS * 8, SS * 8,               /* %cs, %ss */
  95   DS * 8, ES * 8,               /* %ds, %es */
  96   FS * 8, GS * 8,               /* %fs, %gs */
  97   -1, -1, -1, -1, -1, -1, -1, -1,
  98   -1, -1, -1, -1, -1, -1, -1, -1,
  99   -1, -1, -1, -1, -1, -1, -1, -1, -1,
 100   -1, -1, -1, -1, -1, -1, -1, -1,
 101   ORIG_RAX * 8                  /* "orig_eax" */
 102 };
 103 \f
 104
 105 /* Transfering the general-purpose registers between GDB, inferiors
 106    and core files.  */
 107
 108 /* Fill GDB's register cache with the general-purpose register values
 109    in *GREGSETP.  */
 110
 111 void
 112 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 113 {
 114   amd64_supply_native_gregset (regcache, gregsetp, -1);
 115 }
 116
 117 /* Fill register REGNUM (if it is a general-purpose register) in
 118    *GREGSETP with the value in GDB's register cache.  If REGNUM is -1,
 119    do this for all registers.  */
 120
 121 void
 122 fill_gregset (const struct regcache *regcache,
 123               elf_gregset_t *gregsetp, int regnum)
 124 {
 125   amd64_collect_native_gregset (regcache, gregsetp, regnum);
 126 }
 127
 128 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 129
 130 /* Fill GDB's register cache with the floating-point and SSE register
 131    values in *FPREGSETP.  */
 132
 133 void
 134 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 135 {
 136   amd64_supply_fxsave (regcache, -1, fpregsetp);
 137 }
 138
 139 /* Fill register REGNUM (if it is a floating-point or SSE register) in
 140    *FPREGSETP with the value in GDB's register cache.  If REGNUM is
 141    -1, do this for all registers.  */
 142
 143 void
 144 fill_fpregset (const struct regcache *regcache,
 145                elf_fpregset_t *fpregsetp, int regnum)
 146 {
 147   amd64_collect_fxsave (regcache, regnum, fpregsetp);
 148 }
 149 \f
 150
 151 /* Transferring arbitrary registers between GDB and inferior.  */
 152
 153 /* Fetch register REGNUM from the child process.  If REGNUM is -1, do
 154    this for all registers (including the floating point and SSE
 155    registers).  */
 156
 157 static void
 158 amd64_linux_fetch_inferior_registers (struct target_ops *ops,
 159                                       struct regcache *regcache, int regnum)
 160 {
 161   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 162   int tid;
 163
 164   /* GNU/Linux LWP ID's are process ID's.  */
 165   tid = TIDGET (inferior_ptid);
 166   if (tid == 0)
 167     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 168
 169   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 170     {
 171       elf_gregset_t regs;
 172
 173       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 174         perror_with_name (_("Couldn't get registers"));
 175
 176       amd64_supply_native_gregset (regcache, &regs, -1);
 177       if (regnum != -1)
 178         return;
 179     }
 180
 181   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 182     {
 183       elf_fpregset_t fpregs;
 184
 185       if (have_ptrace_getregset)
 186         {
 187           char xstateregs[I386_XSTATE_MAX_SIZE];
 188           struct iovec iov;
 189
 190           iov.iov_base = xstateregs;
 191           iov.iov_len = sizeof (xstateregs);
 192           if (ptrace (PTRACE_GETREGSET, tid,
 193                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 194             perror_with_name (_("Couldn't get extended state status"));
 195
 196           amd64_supply_xsave (regcache, -1, xstateregs);
 197         }
 198       else
 199         {
 200           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 201             perror_with_name (_("Couldn't get floating point status"));
 202
 203           amd64_supply_fxsave (regcache, -1, &fpregs);
 204         }
 205     }
 206 }
 207
 208 /* Store register REGNUM back into the child process.  If REGNUM is
 209    -1, do this for all registers (including the floating-point and SSE
 210    registers).  */
 211
 212 static void
 213 amd64_linux_store_inferior_registers (struct target_ops *ops,
 214                                       struct regcache *regcache, int regnum)
 215 {
 216   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 217   int tid;
 218
 219   /* GNU/Linux LWP ID's are process ID's.  */
 220   tid = TIDGET (inferior_ptid);
 221   if (tid == 0)
 222     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 223
 224   if (regnum == -1 || amd64_native_gregset_supplies_p (gdbarch, regnum))
 225     {
 226       elf_gregset_t regs;
 227
 228       if (ptrace (PTRACE_GETREGS, tid, 0, (long) &regs) < 0)
 229         perror_with_name (_("Couldn't get registers"));
 230
 231       amd64_collect_native_gregset (regcache, &regs, regnum);
 232
 233       if (ptrace (PTRACE_SETREGS, tid, 0, (long) &regs) < 0)
 234         perror_with_name (_("Couldn't write registers"));
 235
 236       if (regnum != -1)
 237         return;
 238     }
 239
 240   if (regnum == -1 || !amd64_native_gregset_supplies_p (gdbarch, regnum))
 241     {
 242       elf_fpregset_t fpregs;
 243
 244       if (have_ptrace_getregset)
 245         {
 246           char xstateregs[I386_XSTATE_MAX_SIZE];
 247           struct iovec iov;
 248
 249           iov.iov_base = xstateregs;
 250           iov.iov_len = sizeof (xstateregs);
 251           if (ptrace (PTRACE_GETREGSET, tid,
 252                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 253             perror_with_name (_("Couldn't get extended state status"));
 254
 255           amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 256
 257           if (ptrace (PTRACE_SETREGSET, tid,
 258                       (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 259             perror_with_name (_("Couldn't write extended state status"));
 260         }
 261       else
 262         {
 263           if (ptrace (PTRACE_GETFPREGS, tid, 0, (long) &fpregs) < 0)
 264             perror_with_name (_("Couldn't get floating point status"));
 265
 266           amd64_collect_fxsave (regcache, regnum, &fpregs);
 267
 268           if (ptrace (PTRACE_SETFPREGS, tid, 0, (long) &fpregs) < 0)
 269             perror_with_name (_("Couldn't write floating point status"));
 270         }
 271     }
 272 }
 273 \f
 274 /* Support for debug registers.  */
 275
 276 static unsigned long
 277 amd64_linux_dr_get (ptid_t ptid, int regnum)
 278 {
 279   int tid;
 280   unsigned long value;
 281
 282   tid = TIDGET (ptid);
 283   if (tid == 0)
 284     tid = PIDGET (ptid);
 285
 286   errno = 0;
 287   value = ptrace (PTRACE_PEEKUSER, tid,
 288                   offsetof (struct user, u_debugreg[regnum]), 0);
 289   if (errno != 0)
 290     perror_with_name (_("Couldn't read debug register"));
 291
 292   return value;
 293 }
 294
 295 /* Set debug register REGNUM to VALUE in only the one LWP of PTID.  */
 296
 297 static void
 298 amd64_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
 299 {
 300   int tid;
 301
 302   tid = TIDGET (ptid);
 303   if (tid == 0)
 304     tid = PIDGET (ptid);
 305
 306   errno = 0;
 307   ptrace (PTRACE_POKEUSER, tid,
 308           offsetof (struct user, u_debugreg[regnum]), value);
 309   if (errno != 0)
 310     perror_with_name (_("Couldn't write debug register"));
 311 }
 312
 313 /* Return the inferior's debug register REGNUM.  */
 314
 315 static CORE_ADDR
 316 amd64_linux_dr_get_addr (int regnum)
 317 {
 318   /* DR6 and DR7 are retrieved with some other way.  */
 319   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 320
 321   return amd64_linux_dr_get (inferior_ptid, regnum);
 322 }
 323
 324 /* Return the inferior's DR7 debug control register.  */
 325
 326 static unsigned long
 327 amd64_linux_dr_get_control (void)
 328 {
 329   return amd64_linux_dr_get (inferior_ptid, DR_CONTROL);
 330 }
 331
 332 /* Get DR_STATUS from only the one LWP of INFERIOR_PTID.  */
 333
 334 static unsigned long
 335 amd64_linux_dr_get_status (void)
 336 {
 337   return amd64_linux_dr_get (inferior_ptid, DR_STATUS);
 338 }
 339
 340 /* Callback for iterate_over_lwps.  Update the debug registers of
 341    LWP.  */
 342
 343 static int
 344 update_debug_registers_callback (struct lwp_info *lwp, void *arg)
 345 {
 346   /* The actual update is done later just before resuming the lwp, we
 347      just mark that the registers need updating.  */
 348   lwp->arch_private->debug_registers_changed = 1;
 349
 350   /* If the lwp isn't stopped, force it to momentarily pause, so we
 351      can update its debug registers.  */
 352   if (!lwp->stopped)
 353     linux_stop_lwp (lwp);
 354
 355   return 0;
 356 }
 357
 358 /* Set DR_CONTROL to CONTROL in all LWPs of the current inferior.  */
 359
 360 static void
 361 amd64_linux_dr_set_control (unsigned long control)
 362 {
 363   ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
 364
 365   iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
 366 }
 367
 368 /* Set address REGNUM (zero based) to ADDR in all LWPs of the current
 369    inferior.  */
 370
 371 static void
 372 amd64_linux_dr_set_addr (int regnum, CORE_ADDR addr)
 373 {
 374   ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
 375
 376   gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
 377
 378   iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
 379 }
 380
 381 /* Called when resuming a thread.
 382    If the debug regs have changed, update the thread's copies.  */
 383
 384 static void
 385 amd64_linux_prepare_to_resume (struct lwp_info *lwp)
 386 {
 387   int clear_status = 0;
 388
 389   if (lwp->arch_private->debug_registers_changed)
 390     {
 391       struct i386_debug_reg_state *state = i386_debug_reg_state ();
 392       int i;
 393
 394       for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 395         if (state->dr_ref_count[i] > 0)
 396           {
 397             amd64_linux_dr_set (lwp->ptid, i, state->dr_mirror[i]);
 398
 399             /* If we're setting a watchpoint, any change the inferior
 400                had done itself to the debug registers needs to be
 401                discarded, otherwise, i386_stopped_data_address can get
 402                confused.  */
 403             clear_status = 1;
 404           }
 405
 406       amd64_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror);
 407
 408       lwp->arch_private->debug_registers_changed = 0;
 409     }
 410
 411   if (clear_status || lwp->stopped_by_watchpoint)
 412     amd64_linux_dr_set (lwp->ptid, DR_STATUS, 0);
 413 }
 414
 415 static void
 416 amd64_linux_new_thread (struct lwp_info *lp)
 417 {
 418   struct arch_lwp_info *info = XCNEW (struct arch_lwp_info);
 419
 420   info->debug_registers_changed = 1;
 421
 422   lp->arch_private = info;
 423 }
 424 \f
 425
 426 /* This function is called by libthread_db as part of its handling of
 427    a request for a thread's local storage address.  */
 428
 429 ps_err_e
 430 ps_get_thread_area (const struct ps_prochandle *ph,
 431                     lwpid_t lwpid, int idx, void **base)
 432 {
 433   if (gdbarch_ptr_bit (target_gdbarch) == 32)
 434     {
 435       /* The full structure is found in <asm-i386/ldt.h>.  The second
 436          integer is the LDT's base_address and that is used to locate
 437          the thread's local storage.  See i386-linux-nat.c more
 438          info.  */
 439       unsigned int desc[4];
 440
 441       /* This code assumes that "int" is 32 bits and that
 442          GET_THREAD_AREA returns no more than 4 int values.  */
 443       gdb_assert (sizeof (int) == 4);
 444 #ifndef PTRACE_GET_THREAD_AREA
 445 #define PTRACE_GET_THREAD_AREA 25
 446 #endif
 447       if  (ptrace (PTRACE_GET_THREAD_AREA,
 448                    lwpid, (void *) (long) idx, (unsigned long) &desc) < 0)
 449         return PS_ERR;
 450
 451       /* Extend the value to 64 bits.  Here it's assumed that a "long"
 452          and a "void *" are the same.  */
 453       (*base) = (void *) (long) desc[1];
 454       return PS_OK;
 455     }
 456   else
 457     {
 458       /* This definition comes from prctl.h, but some kernels may not
 459          have it.  */
 460 #ifndef PTRACE_ARCH_PRCTL
 461 #define PTRACE_ARCH_PRCTL      30
 462 #endif
 463       /* FIXME: ezannoni-2003-07-09 see comment above about include
 464          file order.  We could be getting bogus values for these two.  */
 465       gdb_assert (FS < ELF_NGREG);
 466       gdb_assert (GS < ELF_NGREG);
 467       switch (idx)
 468         {
 469         case FS:
 470           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_FS) == 0)
 471             return PS_OK;
 472           break;
 473         case GS:
 474           if (ptrace (PTRACE_ARCH_PRCTL, lwpid, base, ARCH_GET_GS) == 0)
 475             return PS_OK;
 476           break;
 477         default:                   /* Should not happen.  */
 478           return PS_BADADDR;
 479         }
 480     }
 481   return PS_ERR;               /* ptrace failed.  */
 482 }
 483 \f
 484
 485 static void (*super_post_startup_inferior) (ptid_t ptid);
 486
 487 static void
 488 amd64_linux_child_post_startup_inferior (ptid_t ptid)
 489 {
 490   i386_cleanup_dregs ();
 491   super_post_startup_inferior (ptid);
 492 }
 493 \f
 494
 495 /* When GDB is built as a 64-bit application on linux, the
 496    PTRACE_GETSIGINFO data is always presented in 64-bit layout.  Since
 497    debugging a 32-bit inferior with a 64-bit GDB should look the same
 498    as debugging it with a 32-bit GDB, we do the 32-bit <-> 64-bit
 499    conversion in-place ourselves.  */
 500
 501 /* These types below (compat_*) define a siginfo type that is layout
 502    compatible with the siginfo type exported by the 32-bit userspace
 503    support.  */
 504
 505 typedef int compat_int_t;
 506 typedef unsigned int compat_uptr_t;
 507
 508 typedef int compat_time_t;
 509 typedef int compat_timer_t;
 510 typedef int compat_clock_t;
 511
 512 struct compat_timeval
 513 {
 514   compat_time_t tv_sec;
 515   int tv_usec;
 516 };
 517
 518 typedef union compat_sigval
 519 {
 520   compat_int_t sival_int;
 521   compat_uptr_t sival_ptr;
 522 } compat_sigval_t;
 523
 524 typedef struct compat_siginfo
 525 {
 526   int si_signo;
 527   int si_errno;
 528   int si_code;
 529
 530   union
 531   {
 532     int _pad[((128 / sizeof (int)) - 3)];
 533
 534     /* kill() */
 535     struct
 536     {
 537       unsigned int _pid;
 538       unsigned int _uid;
 539     } _kill;
 540
 541     /* POSIX.1b timers */
 542     struct
 543     {
 544       compat_timer_t _tid;
 545       int _overrun;
 546       compat_sigval_t _sigval;
 547     } _timer;
 548
 549     /* POSIX.1b signals */
 550     struct
 551     {
 552       unsigned int _pid;
 553       unsigned int _uid;
 554       compat_sigval_t _sigval;
 555     } _rt;
 556
 557     /* SIGCHLD */
 558     struct
 559     {
 560       unsigned int _pid;
 561       unsigned int _uid;
 562       int _status;
 563       compat_clock_t _utime;
 564       compat_clock_t _stime;
 565     } _sigchld;
 566
 567     /* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
 568     struct
 569     {
 570       unsigned int _addr;
 571     } _sigfault;
 572
 573     /* SIGPOLL */
 574     struct
 575     {
 576       int _band;
 577       int _fd;
 578     } _sigpoll;
 579   } _sifields;
 580 } compat_siginfo_t;
 581
 582 #define cpt_si_pid _sifields._kill._pid
 583 #define cpt_si_uid _sifields._kill._uid
 584 #define cpt_si_timerid _sifields._timer._tid
 585 #define cpt_si_overrun _sifields._timer._overrun
 586 #define cpt_si_status _sifields._sigchld._status
 587 #define cpt_si_utime _sifields._sigchld._utime
 588 #define cpt_si_stime _sifields._sigchld._stime
 589 #define cpt_si_ptr _sifields._rt._sigval.sival_ptr
 590 #define cpt_si_addr _sifields._sigfault._addr
 591 #define cpt_si_band _sifields._sigpoll._band
 592 #define cpt_si_fd _sifields._sigpoll._fd
 593
 594 /* glibc at least up to 2.3.2 doesn't have si_timerid, si_overrun.
 595    In their place is si_timer1,si_timer2.  */
 596 #ifndef si_timerid
 597 #define si_timerid si_timer1
 598 #endif
 599 #ifndef si_overrun
 600 #define si_overrun si_timer2
 601 #endif
 602
 603 static void
 604 compat_siginfo_from_siginfo (compat_siginfo_t *to, siginfo_t *from)
 605 {
 606   memset (to, 0, sizeof (*to));
 607
 608   to->si_signo = from->si_signo;
 609   to->si_errno = from->si_errno;
 610   to->si_code = from->si_code;
 611
 612   if (to->si_code == SI_TIMER)
 613     {
 614       to->cpt_si_timerid = from->si_timerid;
 615       to->cpt_si_overrun = from->si_overrun;
 616       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 617     }
 618   else if (to->si_code == SI_USER)
 619     {
 620       to->cpt_si_pid = from->si_pid;
 621       to->cpt_si_uid = from->si_uid;
 622     }
 623   else if (to->si_code < 0)
 624     {
 625       to->cpt_si_pid = from->si_pid;
 626       to->cpt_si_uid = from->si_uid;
 627       to->cpt_si_ptr = (intptr_t) from->si_ptr;
 628     }
 629   else
 630     {
 631       switch (to->si_signo)
 632         {
 633         case SIGCHLD:
 634           to->cpt_si_pid = from->si_pid;
 635           to->cpt_si_uid = from->si_uid;
 636           to->cpt_si_status = from->si_status;
 637           to->cpt_si_utime = from->si_utime;
 638           to->cpt_si_stime = from->si_stime;
 639           break;
 640         case SIGILL:
 641         case SIGFPE:
 642         case SIGSEGV:
 643         case SIGBUS:
 644           to->cpt_si_addr = (intptr_t) from->si_addr;
 645           break;
 646         case SIGPOLL:
 647           to->cpt_si_band = from->si_band;
 648           to->cpt_si_fd = from->si_fd;
 649           break;
 650         default:
 651           to->cpt_si_pid = from->si_pid;
 652           to->cpt_si_uid = from->si_uid;
 653           to->cpt_si_ptr = (intptr_t) from->si_ptr;
 654           break;
 655         }
 656     }
 657 }
 658
 659 static void
 660 siginfo_from_compat_siginfo (siginfo_t *to, compat_siginfo_t *from)
 661 {
 662   memset (to, 0, sizeof (*to));
 663
 664   to->si_signo = from->si_signo;
 665   to->si_errno = from->si_errno;
 666   to->si_code = from->si_code;
 667
 668   if (to->si_code == SI_TIMER)
 669     {
 670       to->si_timerid = from->cpt_si_timerid;
 671       to->si_overrun = from->cpt_si_overrun;
 672       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 673     }
 674   else if (to->si_code == SI_USER)
 675     {
 676       to->si_pid = from->cpt_si_pid;
 677       to->si_uid = from->cpt_si_uid;
 678     }
 679   if (to->si_code < 0)
 680     {
 681       to->si_pid = from->cpt_si_pid;
 682       to->si_uid = from->cpt_si_uid;
 683       to->si_ptr = (void *) (intptr_t) from->cpt_si_ptr;
 684     }
 685   else
 686     {
 687       switch (to->si_signo)
 688         {
 689         case SIGCHLD:
 690           to->si_pid = from->cpt_si_pid;
 691           to->si_uid = from->cpt_si_uid;
 692           to->si_status = from->cpt_si_status;
 693           to->si_utime = from->cpt_si_utime;
 694           to->si_stime = from->cpt_si_stime;
 695           break;
 696         case SIGILL:
 697         case SIGFPE:
 698         case SIGSEGV:
 699         case SIGBUS:
 700           to->si_addr = (void *) (intptr_t) from->cpt_si_addr;
 701           break;
 702         case SIGPOLL:
 703           to->si_band = from->cpt_si_band;
 704           to->si_fd = from->cpt_si_fd;
 705           break;
 706         default:
 707           to->si_pid = from->cpt_si_pid;
 708           to->si_uid = from->cpt_si_uid;
 709           to->si_ptr = (void* ) (intptr_t) from->cpt_si_ptr;
 710           break;
 711         }
 712     }
 713 }
 714
 715 /* Convert a native/host siginfo object, into/from the siginfo in the
 716    layout of the inferiors' architecture.  Returns true if any
 717    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 718    from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
 719    INF.  */
 720
 721 static int
 722 amd64_linux_siginfo_fixup (struct siginfo *native, gdb_byte *inf, int direction)
 723 {
 724   /* Is the inferior 32-bit?  If so, then do fixup the siginfo
 725      object.  */
 726   if (gdbarch_addr_bit (get_frame_arch (get_current_frame ())) == 32)
 727     {
 728       gdb_assert (sizeof (struct siginfo) == sizeof (compat_siginfo_t));
 729
 730       if (direction == 0)
 731         compat_siginfo_from_siginfo ((struct compat_siginfo *) inf, native);
 732       else
 733         siginfo_from_compat_siginfo (native, (struct compat_siginfo *) inf);
 734
 735       return 1;
 736     }
 737   else
 738     return 0;
 739 }
 740
 741 /* Get Linux/x86 target description from running target.
 742
 743    Value of CS segment register:
 744      1. 64bit process: 0x33.
 745      2. 32bit process: 0x23.
 746  */
 747
 748 #define AMD64_LINUX_USER64_CS   0x33
 749
 750 static const struct target_desc *
 751 amd64_linux_read_description (struct target_ops *ops)
 752 {
 753   unsigned long cs;
 754   int tid;
 755   int is_64bit;
 756   static uint64_t xcr0;
 757
 758   /* GNU/Linux LWP ID's are process ID's.  */
 759   tid = TIDGET (inferior_ptid);
 760   if (tid == 0)
 761     tid = PIDGET (inferior_ptid); /* Not a threaded program.  */
 762
 763   /* Get CS register.  */
 764   errno = 0;
 765   cs = ptrace (PTRACE_PEEKUSER, tid,
 766                offsetof (struct user_regs_struct, cs), 0);
 767   if (errno != 0)
 768     perror_with_name (_("Couldn't get CS register"));
 769
 770   is_64bit = cs == AMD64_LINUX_USER64_CS;
 771
 772   if (have_ptrace_getregset == -1)
 773     {
 774       uint64_t xstateregs[(I386_XSTATE_SSE_SIZE / sizeof (uint64_t))];
 775       struct iovec iov;
 776
 777       iov.iov_base = xstateregs;
 778       iov.iov_len = sizeof (xstateregs);
 779
 780       /* Check if PTRACE_GETREGSET works.  */
 781       if (ptrace (PTRACE_GETREGSET, tid,
 782                   (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 783         have_ptrace_getregset = 0;
 784       else
 785         {
 786           have_ptrace_getregset = 1;
 787
 788           /* Get XCR0 from XSAVE extended state.  */
 789           xcr0 = xstateregs[(I386_LINUX_XSAVE_XCR0_OFFSET
 790                              / sizeof (uint64_t))];
 791         }
 792     }
 793
 794   /* Check the native XCR0 only if PTRACE_GETREGSET is available.  */
 795   if (have_ptrace_getregset
 796       && (xcr0 & I386_XSTATE_AVX_MASK) == I386_XSTATE_AVX_MASK)
 797     {
 798       if (is_64bit)
 799         return tdesc_amd64_avx_linux;
 800       else
 801         return tdesc_i386_avx_linux;
 802     }
 803   else
 804     {
 805       if (is_64bit)
 806         return tdesc_amd64_linux;
 807       else
 808         return tdesc_i386_linux;
 809     }
 810 }
 811
 812 /* Provide a prototype to silence -Wmissing-prototypes.  */
 813 void _initialize_amd64_linux_nat (void);
 814
 815 void
 816 _initialize_amd64_linux_nat (void)
 817 {
 818   struct target_ops *t;
 819
 820   amd64_native_gregset32_reg_offset = amd64_linux_gregset32_reg_offset;
 821   amd64_native_gregset32_num_regs = I386_LINUX_NUM_REGS;
 822   amd64_native_gregset64_reg_offset = amd64_linux_gregset_reg_offset;
 823   amd64_native_gregset64_num_regs = AMD64_LINUX_NUM_REGS;
 824
 825   gdb_assert (ARRAY_SIZE (amd64_linux_gregset32_reg_offset)
 826               == amd64_native_gregset32_num_regs);
 827
 828   /* Fill in the generic GNU/Linux methods.  */
 829   t = linux_target ();
 830
 831   i386_use_watchpoints (t);
 832
 833   i386_dr_low.set_control = amd64_linux_dr_set_control;
 834   i386_dr_low.set_addr = amd64_linux_dr_set_addr;
 835   i386_dr_low.get_addr = amd64_linux_dr_get_addr;
 836   i386_dr_low.get_status = amd64_linux_dr_get_status;
 837   i386_dr_low.get_control = amd64_linux_dr_get_control;
 838   i386_set_debug_register_length (8);
 839
 840   /* Override the GNU/Linux inferior startup hook.  */
 841   super_post_startup_inferior = t->to_post_startup_inferior;
 842   t->to_post_startup_inferior = amd64_linux_child_post_startup_inferior;
 843
 844   /* Add our register access methods.  */
 845   t->to_fetch_registers = amd64_linux_fetch_inferior_registers;
 846   t->to_store_registers = amd64_linux_store_inferior_registers;
 847
 848   t->to_read_description = amd64_linux_read_description;
 849
 850   /* Register the target.  */
 851   linux_nat_add_target (t);
 852   linux_nat_set_new_thread (t, amd64_linux_new_thread);
 853   linux_nat_set_siginfo_fixup (t, amd64_linux_siginfo_fixup);
 854   linux_nat_set_prepare_to_resume (t, amd64_linux_prepare_to_resume);
 855 }