gdb/rs6000-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2013 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "inferior.h"
  22 #include "target.h"
  23 #include "gdbcore.h"
  24 #include "symfile.h"
  25 #include "objfiles.h"
  26 #include "libbfd.h"             /* For bfd_default_set_arch_mach (FIXME) */
  27 #include "bfd.h"
  28 #include "exceptions.h"
  29 #include "gdb-stabs.h"
  30 #include "regcache.h"
  31 #include "arch-utils.h"
  32 #include "inf-child.h"
  33 #include "inf-ptrace.h"
  34 #include "ppc-tdep.h"
  35 #include "rs6000-tdep.h"
  36 #include "rs6000-aix-tdep.h"
  37 #include "exec.h"
  38 #include "observer.h"
  39 #include "xcoffread.h"
  40
  41 #include <sys/ptrace.h>
  42 #include <sys/reg.h>
  43
  44 #include <sys/dir.h>
  45 #include <sys/user.h>
  46 #include <signal.h>
  47 #include <sys/ioctl.h>
  48 #include <fcntl.h>
  49 #include <errno.h>
  50
  51 #include <a.out.h>
  52 #include <sys/file.h>
  53 #include "gdb_stat.h"
  54 #include "gdb_bfd.h"
  55 #include <sys/core.h>
  56 #define __LDINFO_PTRACE32__     /* for __ld_info32 */
  57 #define __LDINFO_PTRACE64__     /* for __ld_info64 */
  58 #include <sys/ldr.h>
  59 #include <sys/systemcfg.h>
  60
  61 /* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
  62    debugging 32-bit and 64-bit processes.  Define a typedef and macros for
  63    accessing fields in the appropriate structures.  */
  64
  65 /* In 32-bit compilation mode (which is the only mode from which ptrace()
  66    works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */
  67
  68 #if defined (__ld_info32) || defined (__ld_info64)
  69 # define ARCH3264
  70 #endif
  71
  72 /* Return whether the current architecture is 64-bit.  */
  73
  74 #ifndef ARCH3264
  75 # define ARCH64() 0
  76 #else
  77 # define ARCH64() (register_size (target_gdbarch (), 0) == 8)
  78 #endif
  79
  80 static void exec_one_dummy_insn (struct regcache *);
  81
  82 static LONGEST rs6000_xfer_shared_libraries
  83   (struct target_ops *ops, enum target_object object,
  84    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
  85    ULONGEST offset, LONGEST len);
  86
  87 /* Given REGNO, a gdb register number, return the corresponding
  88    number suitable for use as a ptrace() parameter.  Return -1 if
  89    there's no suitable mapping.  Also, set the int pointed to by
  90    ISFLOAT to indicate whether REGNO is a floating point register.  */
  91
  92 static int
  93 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  94 {
  95   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  96
  97   *isfloat = 0;
  98   if (tdep->ppc_gp0_regnum <= regno
  99       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
 100     return regno;
 101   else if (tdep->ppc_fp0_regnum >= 0
 102            && tdep->ppc_fp0_regnum <= regno
 103            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 104     {
 105       *isfloat = 1;
 106       return regno - tdep->ppc_fp0_regnum + FPR0;
 107     }
 108   else if (regno == gdbarch_pc_regnum (gdbarch))
 109     return IAR;
 110   else if (regno == tdep->ppc_ps_regnum)
 111     return MSR;
 112   else if (regno == tdep->ppc_cr_regnum)
 113     return CR;
 114   else if (regno == tdep->ppc_lr_regnum)
 115     return LR;
 116   else if (regno == tdep->ppc_ctr_regnum)
 117     return CTR;
 118   else if (regno == tdep->ppc_xer_regnum)
 119     return XER;
 120   else if (tdep->ppc_fpscr_regnum >= 0
 121            && regno == tdep->ppc_fpscr_regnum)
 122     return FPSCR;
 123   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 124     return MQ;
 125   else
 126     return -1;
 127 }
 128
 129 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 130
 131 static int
 132 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 133 {
 134 #ifdef HAVE_PTRACE64
 135   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 136 #else
 137   int ret = ptrace (req, id, (int *)addr, data, buf);
 138 #endif
 139 #if 0
 140   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 141           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 142 #endif
 143   return ret;
 144 }
 145
 146 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 147
 148 static int
 149 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 150 {
 151 #ifdef ARCH3264
 152 #  ifdef HAVE_PTRACE64
 153   int ret = ptrace64 (req, id, addr, data, buf);
 154 #  else
 155   int ret = ptracex (req, id, addr, data, buf);
 156 #  endif
 157 #else
 158   int ret = 0;
 159 #endif
 160 #if 0
 161   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 162           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 163 #endif
 164   return ret;
 165 }
 166
 167 /* Fetch register REGNO from the inferior.  */
 168
 169 static void
 170 fetch_register (struct regcache *regcache, int regno)
 171 {
 172   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 173   int addr[MAX_REGISTER_SIZE];
 174   int nr, isfloat;
 175
 176   /* Retrieved values may be -1, so infer errors from errno.  */
 177   errno = 0;
 178
 179   nr = regmap (gdbarch, regno, &isfloat);
 180
 181   /* Floating-point registers.  */
 182   if (isfloat)
 183     rs6000_ptrace32 (PT_READ_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 184
 185   /* Bogus register number.  */
 186   else if (nr < 0)
 187     {
 188       if (regno >= gdbarch_num_regs (gdbarch))
 189         fprintf_unfiltered (gdb_stderr,
 190                             "gdb error: register no %d not implemented.\n",
 191                             regno);
 192       return;
 193     }
 194
 195   /* Fixed-point registers.  */
 196   else
 197     {
 198       if (!ARCH64 ())
 199         *addr = rs6000_ptrace32 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 200                                  (int *) nr, 0, 0);
 201       else
 202         {
 203           /* PT_READ_GPR requires the buffer parameter to point to long long,
 204              even if the register is really only 32 bits.  */
 205           long long buf;
 206           rs6000_ptrace64 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 207                            nr, 0, &buf);
 208           if (register_size (gdbarch, regno) == 8)
 209             memcpy (addr, &buf, 8);
 210           else
 211             *addr = buf;
 212         }
 213     }
 214
 215   if (!errno)
 216     regcache_raw_supply (regcache, regno, (char *) addr);
 217   else
 218     {
 219 #if 0
 220       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 221       perror (_("ptrace read"));
 222 #endif
 223       errno = 0;
 224     }
 225 }
 226
 227 /* Store register REGNO back into the inferior.  */
 228
 229 static void
 230 store_register (struct regcache *regcache, int regno)
 231 {
 232   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 233   int addr[MAX_REGISTER_SIZE];
 234   int nr, isfloat;
 235
 236   /* Fetch the register's value from the register cache.  */
 237   regcache_raw_collect (regcache, regno, addr);
 238
 239   /* -1 can be a successful return value, so infer errors from errno.  */
 240   errno = 0;
 241
 242   nr = regmap (gdbarch, regno, &isfloat);
 243
 244   /* Floating-point registers.  */
 245   if (isfloat)
 246     rs6000_ptrace32 (PT_WRITE_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 247
 248   /* Bogus register number.  */
 249   else if (nr < 0)
 250     {
 251       if (regno >= gdbarch_num_regs (gdbarch))
 252         fprintf_unfiltered (gdb_stderr,
 253                             "gdb error: register no %d not implemented.\n",
 254                             regno);
 255     }
 256
 257   /* Fixed-point registers.  */
 258   else
 259     {
 260       if (regno == gdbarch_sp_regnum (gdbarch))
 261         /* Execute one dummy instruction (which is a breakpoint) in inferior
 262            process to give kernel a chance to do internal housekeeping.
 263            Otherwise the following ptrace(2) calls will mess up user stack
 264            since kernel will get confused about the bottom of the stack
 265            (%sp).  */
 266         exec_one_dummy_insn (regcache);
 267
 268       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 269          the register's value is passed by value, but for 64-bit inferiors,
 270          the address of a buffer containing the value is passed.  */
 271       if (!ARCH64 ())
 272         rs6000_ptrace32 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 273                          (int *) nr, *addr, 0);
 274       else
 275         {
 276           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 277              area, even if the register is really only 32 bits.  */
 278           long long buf;
 279           if (register_size (gdbarch, regno) == 8)
 280             memcpy (&buf, addr, 8);
 281           else
 282             buf = *addr;
 283           rs6000_ptrace64 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 284                            nr, 0, &buf);
 285         }
 286     }
 287
 288   if (errno)
 289     {
 290       perror (_("ptrace write"));
 291       errno = 0;
 292     }
 293 }
 294
 295 /* Read from the inferior all registers if REGNO == -1 and just register
 296    REGNO otherwise.  */
 297
 298 static void
 299 rs6000_fetch_inferior_registers (struct target_ops *ops,
 300                                  struct regcache *regcache, int regno)
 301 {
 302   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 303   if (regno != -1)
 304     fetch_register (regcache, regno);
 305
 306   else
 307     {
 308       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 309
 310       /* Read 32 general purpose registers.  */
 311       for (regno = tdep->ppc_gp0_regnum;
 312            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 313            regno++)
 314         {
 315           fetch_register (regcache, regno);
 316         }
 317
 318       /* Read general purpose floating point registers.  */
 319       if (tdep->ppc_fp0_regnum >= 0)
 320         for (regno = 0; regno < ppc_num_fprs; regno++)
 321           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 322
 323       /* Read special registers.  */
 324       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 325       fetch_register (regcache, tdep->ppc_ps_regnum);
 326       fetch_register (regcache, tdep->ppc_cr_regnum);
 327       fetch_register (regcache, tdep->ppc_lr_regnum);
 328       fetch_register (regcache, tdep->ppc_ctr_regnum);
 329       fetch_register (regcache, tdep->ppc_xer_regnum);
 330       if (tdep->ppc_fpscr_regnum >= 0)
 331         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 332       if (tdep->ppc_mq_regnum >= 0)
 333         fetch_register (regcache, tdep->ppc_mq_regnum);
 334     }
 335 }
 336
 337 /* Store our register values back into the inferior.
 338    If REGNO is -1, do this for all registers.
 339    Otherwise, REGNO specifies which register (so we can save time).  */
 340
 341 static void
 342 rs6000_store_inferior_registers (struct target_ops *ops,
 343                                  struct regcache *regcache, int regno)
 344 {
 345   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 346   if (regno != -1)
 347     store_register (regcache, regno);
 348
 349   else
 350     {
 351       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 352
 353       /* Write general purpose registers first.  */
 354       for (regno = tdep->ppc_gp0_regnum;
 355            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 356            regno++)
 357         {
 358           store_register (regcache, regno);
 359         }
 360
 361       /* Write floating point registers.  */
 362       if (tdep->ppc_fp0_regnum >= 0)
 363         for (regno = 0; regno < ppc_num_fprs; regno++)
 364           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 365
 366       /* Write special registers.  */
 367       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 368       store_register (regcache, tdep->ppc_ps_regnum);
 369       store_register (regcache, tdep->ppc_cr_regnum);
 370       store_register (regcache, tdep->ppc_lr_regnum);
 371       store_register (regcache, tdep->ppc_ctr_regnum);
 372       store_register (regcache, tdep->ppc_xer_regnum);
 373       if (tdep->ppc_fpscr_regnum >= 0)
 374         store_register (regcache, tdep->ppc_fpscr_regnum);
 375       if (tdep->ppc_mq_regnum >= 0)
 376         store_register (regcache, tdep->ppc_mq_regnum);
 377     }
 378 }
 379
 380
 381 /* Attempt a transfer all LEN bytes starting at OFFSET between the
 382    inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer.
 383    Return the number of bytes actually transferred.  */
 384
 385 static LONGEST
 386 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 387                      const char *annex, gdb_byte *readbuf,
 388                      const gdb_byte *writebuf,
 389                      ULONGEST offset, LONGEST len)
 390 {
 391   pid_t pid = ptid_get_pid (inferior_ptid);
 392   int arch64 = ARCH64 ();
 393
 394   switch (object)
 395     {
 396     case TARGET_OBJECT_LIBRARIES_AIX:
 397       return rs6000_xfer_shared_libraries (ops, object, annex,
 398                                            readbuf, writebuf,
 399                                            offset, len);
 400     case TARGET_OBJECT_MEMORY:
 401       {
 402         union
 403         {
 404           PTRACE_TYPE_RET word;
 405           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 406         } buffer;
 407         ULONGEST rounded_offset;
 408         LONGEST partial_len;
 409
 410         /* Round the start offset down to the next long word
 411            boundary.  */
 412         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 413
 414         /* Since ptrace will transfer a single word starting at that
 415            rounded_offset the partial_len needs to be adjusted down to
 416            that (remember this function only does a single transfer).
 417            Should the required length be even less, adjust it down
 418            again.  */
 419         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 420         if (partial_len > len)
 421           partial_len = len;
 422
 423         if (writebuf)
 424           {
 425             /* If OFFSET:PARTIAL_LEN is smaller than
 426                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 427                be needed.  Read in the entire word.  */
 428             if (rounded_offset < offset
 429                 || (offset + partial_len
 430                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 431               {
 432                 /* Need part of initial word -- fetch it.  */
 433                 if (arch64)
 434                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 435                                                  rounded_offset, 0, NULL);
 436                 else
 437                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 438                                                  (int *) (uintptr_t)
 439                                                  rounded_offset,
 440                                                  0, NULL);
 441               }
 442
 443             /* Copy data to be written over corresponding part of
 444                buffer.  */
 445             memcpy (buffer.byte + (offset - rounded_offset),
 446                     writebuf, partial_len);
 447
 448             errno = 0;
 449             if (arch64)
 450               rs6000_ptrace64 (PT_WRITE_D, pid,
 451                                rounded_offset, buffer.word, NULL);
 452             else
 453               rs6000_ptrace32 (PT_WRITE_D, pid,
 454                                (int *) (uintptr_t) rounded_offset,
 455                                buffer.word, NULL);
 456             if (errno)
 457               return 0;
 458           }
 459
 460         if (readbuf)
 461           {
 462             errno = 0;
 463             if (arch64)
 464               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 465                                              rounded_offset, 0, NULL);
 466             else
 467               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 468                                              (int *)(uintptr_t)rounded_offset,
 469                                              0, NULL);
 470             if (errno)
 471               return 0;
 472
 473             /* Copy appropriate bytes out of the buffer.  */
 474             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 475                     partial_len);
 476           }
 477
 478         return partial_len;
 479       }
 480
 481     default:
 482       return -1;
 483     }
 484 }
 485
 486 /* Wait for the child specified by PTID to do something.  Return the
 487    process ID of the child, or MINUS_ONE_PTID in case of error; store
 488    the status in *OURSTATUS.  */
 489
 490 static ptid_t
 491 rs6000_wait (struct target_ops *ops,
 492              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 493 {
 494   pid_t pid;
 495   int status, save_errno;
 496
 497   do
 498     {
 499       set_sigint_trap ();
 500
 501       do
 502         {
 503           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 504           save_errno = errno;
 505         }
 506       while (pid == -1 && errno == EINTR);
 507
 508       clear_sigint_trap ();
 509
 510       if (pid == -1)
 511         {
 512           fprintf_unfiltered (gdb_stderr,
 513                               _("Child process unexpectedly missing: %s.\n"),
 514                               safe_strerror (save_errno));
 515
 516           /* Claim it exited with unknown signal.  */
 517           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 518           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 519           return inferior_ptid;
 520         }
 521
 522       /* Ignore terminated detached child processes.  */
 523       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 524         pid = -1;
 525     }
 526   while (pid == -1);
 527
 528   /* AIX has a couple of strange returns from wait().  */
 529
 530   /* stop after load" status.  */
 531   if (status == 0x57c)
 532     ourstatus->kind = TARGET_WAITKIND_LOADED;
 533   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 534   else if (status == 0x7f)
 535     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 536   /* A normal waitstatus.  Let the usual macros deal with it.  */
 537   else
 538     store_waitstatus (ourstatus, status);
 539
 540   return pid_to_ptid (pid);
 541 }
 542
 543 /* Execute one dummy breakpoint instruction.  This way we give the kernel
 544    a chance to do some housekeeping and update inferior's internal data,
 545    including u_area.  */
 546
 547 static void
 548 exec_one_dummy_insn (struct regcache *regcache)
 549 {
 550 #define DUMMY_INSN_ADDR AIX_TEXT_SEGMENT_BASE+0x200
 551
 552   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 553   int ret, status, pid;
 554   CORE_ADDR prev_pc;
 555   void *bp;
 556
 557   /* We plant one dummy breakpoint into DUMMY_INSN_ADDR address.  We
 558      assume that this address will never be executed again by the real
 559      code.  */
 560
 561   bp = deprecated_insert_raw_breakpoint (gdbarch, NULL, DUMMY_INSN_ADDR);
 562
 563   /* You might think this could be done with a single ptrace call, and
 564      you'd be correct for just about every platform I've ever worked
 565      on.  However, rs6000-ibm-aix4.1.3 seems to have screwed this up --
 566      the inferior never hits the breakpoint (it's also worth noting
 567      powerpc-ibm-aix4.1.3 works correctly).  */
 568   prev_pc = regcache_read_pc (regcache);
 569   regcache_write_pc (regcache, DUMMY_INSN_ADDR);
 570   if (ARCH64 ())
 571     ret = rs6000_ptrace64 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 572                            1, 0, NULL);
 573   else
 574     ret = rs6000_ptrace32 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 575                            (int *) 1, 0, NULL);
 576
 577   if (ret != 0)
 578     perror (_("pt_continue"));
 579
 580   do
 581     {
 582       pid = waitpid (ptid_get_pid (inferior_ptid), &status, 0);
 583     }
 584   while (pid != ptid_get_pid (inferior_ptid));
 585
 586   regcache_write_pc (regcache, prev_pc);
 587   deprecated_remove_raw_breakpoint (gdbarch, bp);
 588 }
 589 \f
 590
 591 /* Set the current architecture from the host running GDB.  Called when
 592    starting a child process.  */
 593
 594 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 595                                       char *allargs, char **env, int from_tty);
 596 static void
 597 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 598                         char *allargs, char **env, int from_tty)
 599 {
 600   enum bfd_architecture arch;
 601   unsigned long mach;
 602   bfd abfd;
 603   struct gdbarch_info info;
 604
 605   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 606
 607   if (__power_rs ())
 608     {
 609       arch = bfd_arch_rs6000;
 610       mach = bfd_mach_rs6k;
 611     }
 612   else
 613     {
 614       arch = bfd_arch_powerpc;
 615       mach = bfd_mach_ppc;
 616     }
 617
 618   /* FIXME: schauer/2002-02-25:
 619      We don't know if we are executing a 32 or 64 bit executable,
 620      and have no way to pass the proper word size to rs6000_gdbarch_init.
 621      So we have to avoid switching to a new architecture, if the architecture
 622      matches already.
 623      Blindly calling rs6000_gdbarch_init used to work in older versions of
 624      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 625      determine the wordsize.  */
 626   if (exec_bfd)
 627     {
 628       const struct bfd_arch_info *exec_bfd_arch_info;
 629
 630       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 631       if (arch == exec_bfd_arch_info->arch)
 632         return;
 633     }
 634
 635   bfd_default_set_arch_mach (&abfd, arch, mach);
 636
 637   gdbarch_info_init (&info);
 638   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 639   info.abfd = exec_bfd;
 640
 641   if (!gdbarch_update_p (info))
 642     internal_error (__FILE__, __LINE__,
 643                     _("rs6000_create_inferior: failed "
 644                       "to select architecture"));
 645 }
 646 \f
 647
 648 /* Shared Object support.  */
 649
 650 /* Return the LdInfo data for the given process.  Raises an error
 651    if the data could not be obtained.
 652
 653    The returned value must be deallocated after use.  */
 654
 655 static gdb_byte *
 656 rs6000_ptrace_ldinfo (ptid_t ptid)
 657 {
 658   const int pid = ptid_get_pid (ptid);
 659   int ldi_size = 1024;
 660   gdb_byte *ldi = xmalloc (ldi_size);
 661   int rc = -1;
 662
 663   while (1)
 664     {
 665       if (ARCH64 ())
 666         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 667                               NULL);
 668       else
 669         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 670
 671       if (rc != -1)
 672         break; /* Success, we got the entire ld_info data.  */
 673
 674       if (errno != ENOMEM)
 675         perror_with_name (_("ptrace ldinfo"));
 676
 677       /* ldi is not big enough.  Double it and try again.  */
 678       ldi_size *= 2;
 679       ldi = xrealloc (ldi, ldi_size);
 680     }
 681
 682   return ldi;
 683 }
 684
 685 /* Implement the to_xfer_partial target_ops method for
 686    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 687
 688 static LONGEST
 689 rs6000_xfer_shared_libraries
 690   (struct target_ops *ops, enum target_object object,
 691    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 692    ULONGEST offset, LONGEST len)
 693 {
 694   gdb_byte *ldi_buf;
 695   ULONGEST result;
 696   struct cleanup *cleanup;
 697
 698   /* This function assumes that it is being run with a live process.
 699      Core files are handled via gdbarch.  */
 700   gdb_assert (target_has_execution);
 701
 702   if (writebuf)
 703     return -1;
 704
 705   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 706   gdb_assert (ldi_buf != NULL);
 707   cleanup = make_cleanup (xfree, ldi_buf);
 708   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 709                                       readbuf, offset, len, 1);
 710   xfree (ldi_buf);
 711
 712   do_cleanups (cleanup);
 713   return result;
 714 }
 715
 716 void _initialize_rs6000_nat (void);
 717
 718 void
 719 _initialize_rs6000_nat (void)
 720 {
 721   struct target_ops *t;
 722
 723   t = inf_ptrace_target ();
 724   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 725   t->to_store_registers = rs6000_store_inferior_registers;
 726   t->to_xfer_partial = rs6000_xfer_partial;
 727
 728   super_create_inferior = t->to_create_inferior;
 729   t->to_create_inferior = rs6000_create_inferior;
 730
 731   t->to_wait = rs6000_wait;
 732
 733   add_target (t);
 734 }