gdb/rs6000-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2014 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
  50 #include <a.out.h>
  51 #include <sys/file.h>
  52 #include <sys/stat.h>
  53 #include "gdb_bfd.h"
  54 #include <sys/core.h>
  55 #define __LDINFO_PTRACE32__     /* for __ld_info32 */
  56 #define __LDINFO_PTRACE64__     /* for __ld_info64 */
  57 #include <sys/ldr.h>
  58 #include <sys/systemcfg.h>
  59
  60 /* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
  61    debugging 32-bit and 64-bit processes.  Define a typedef and macros for
  62    accessing fields in the appropriate structures.  */
  63
  64 /* In 32-bit compilation mode (which is the only mode from which ptrace()
  65    works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */
  66
  67 #if defined (__ld_info32) || defined (__ld_info64)
  68 # define ARCH3264
  69 #endif
  70
  71 /* Return whether the current architecture is 64-bit.  */
  72
  73 #ifndef ARCH3264
  74 # define ARCH64() 0
  75 #else
  76 # define ARCH64() (register_size (target_gdbarch (), 0) == 8)
  77 #endif
  78
  79 static void exec_one_dummy_insn (struct regcache *);
  80
  81 static target_xfer_partial_ftype rs6000_xfer_shared_libraries;
  82
  83 /* Given REGNO, a gdb register number, return the corresponding
  84    number suitable for use as a ptrace() parameter.  Return -1 if
  85    there's no suitable mapping.  Also, set the int pointed to by
  86    ISFLOAT to indicate whether REGNO is a floating point register.  */
  87
  88 static int
  89 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  90 {
  91   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  92
  93   *isfloat = 0;
  94   if (tdep->ppc_gp0_regnum <= regno
  95       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
  96     return regno;
  97   else if (tdep->ppc_fp0_regnum >= 0
  98            && tdep->ppc_fp0_regnum <= regno
  99            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 100     {
 101       *isfloat = 1;
 102       return regno - tdep->ppc_fp0_regnum + FPR0;
 103     }
 104   else if (regno == gdbarch_pc_regnum (gdbarch))
 105     return IAR;
 106   else if (regno == tdep->ppc_ps_regnum)
 107     return MSR;
 108   else if (regno == tdep->ppc_cr_regnum)
 109     return CR;
 110   else if (regno == tdep->ppc_lr_regnum)
 111     return LR;
 112   else if (regno == tdep->ppc_ctr_regnum)
 113     return CTR;
 114   else if (regno == tdep->ppc_xer_regnum)
 115     return XER;
 116   else if (tdep->ppc_fpscr_regnum >= 0
 117            && regno == tdep->ppc_fpscr_regnum)
 118     return FPSCR;
 119   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 120     return MQ;
 121   else
 122     return -1;
 123 }
 124
 125 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 126
 127 static int
 128 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 129 {
 130 #ifdef HAVE_PTRACE64
 131   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 132 #else
 133   int ret = ptrace (req, id, (int *)addr, data, buf);
 134 #endif
 135 #if 0
 136   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 137           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 138 #endif
 139   return ret;
 140 }
 141
 142 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 143
 144 static int
 145 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 146 {
 147 #ifdef ARCH3264
 148 #  ifdef HAVE_PTRACE64
 149   int ret = ptrace64 (req, id, addr, data, buf);
 150 #  else
 151   int ret = ptracex (req, id, addr, data, buf);
 152 #  endif
 153 #else
 154   int ret = 0;
 155 #endif
 156 #if 0
 157   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 158           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 159 #endif
 160   return ret;
 161 }
 162
 163 /* Fetch register REGNO from the inferior.  */
 164
 165 static void
 166 fetch_register (struct regcache *regcache, int regno)
 167 {
 168   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 169   int addr[MAX_REGISTER_SIZE];
 170   int nr, isfloat;
 171
 172   /* Retrieved values may be -1, so infer errors from errno.  */
 173   errno = 0;
 174
 175   nr = regmap (gdbarch, regno, &isfloat);
 176
 177   /* Floating-point registers.  */
 178   if (isfloat)
 179     rs6000_ptrace32 (PT_READ_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 180
 181   /* Bogus register number.  */
 182   else if (nr < 0)
 183     {
 184       if (regno >= gdbarch_num_regs (gdbarch))
 185         fprintf_unfiltered (gdb_stderr,
 186                             "gdb error: register no %d not implemented.\n",
 187                             regno);
 188       return;
 189     }
 190
 191   /* Fixed-point registers.  */
 192   else
 193     {
 194       if (!ARCH64 ())
 195         *addr = rs6000_ptrace32 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 196                                  (int *) nr, 0, 0);
 197       else
 198         {
 199           /* PT_READ_GPR requires the buffer parameter to point to long long,
 200              even if the register is really only 32 bits.  */
 201           long long buf;
 202           rs6000_ptrace64 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 203                            nr, 0, &buf);
 204           if (register_size (gdbarch, regno) == 8)
 205             memcpy (addr, &buf, 8);
 206           else
 207             *addr = buf;
 208         }
 209     }
 210
 211   if (!errno)
 212     regcache_raw_supply (regcache, regno, (char *) addr);
 213   else
 214     {
 215 #if 0
 216       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 217       perror (_("ptrace read"));
 218 #endif
 219       errno = 0;
 220     }
 221 }
 222
 223 /* Store register REGNO back into the inferior.  */
 224
 225 static void
 226 store_register (struct regcache *regcache, int regno)
 227 {
 228   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 229   int addr[MAX_REGISTER_SIZE];
 230   int nr, isfloat;
 231
 232   /* Fetch the register's value from the register cache.  */
 233   regcache_raw_collect (regcache, regno, addr);
 234
 235   /* -1 can be a successful return value, so infer errors from errno.  */
 236   errno = 0;
 237
 238   nr = regmap (gdbarch, regno, &isfloat);
 239
 240   /* Floating-point registers.  */
 241   if (isfloat)
 242     rs6000_ptrace32 (PT_WRITE_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 243
 244   /* Bogus register number.  */
 245   else if (nr < 0)
 246     {
 247       if (regno >= gdbarch_num_regs (gdbarch))
 248         fprintf_unfiltered (gdb_stderr,
 249                             "gdb error: register no %d not implemented.\n",
 250                             regno);
 251     }
 252
 253   /* Fixed-point registers.  */
 254   else
 255     {
 256       if (regno == gdbarch_sp_regnum (gdbarch))
 257         /* Execute one dummy instruction (which is a breakpoint) in inferior
 258            process to give kernel a chance to do internal housekeeping.
 259            Otherwise the following ptrace(2) calls will mess up user stack
 260            since kernel will get confused about the bottom of the stack
 261            (%sp).  */
 262         exec_one_dummy_insn (regcache);
 263
 264       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 265          the register's value is passed by value, but for 64-bit inferiors,
 266          the address of a buffer containing the value is passed.  */
 267       if (!ARCH64 ())
 268         rs6000_ptrace32 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 269                          (int *) nr, *addr, 0);
 270       else
 271         {
 272           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 273              area, even if the register is really only 32 bits.  */
 274           long long buf;
 275           if (register_size (gdbarch, regno) == 8)
 276             memcpy (&buf, addr, 8);
 277           else
 278             buf = *addr;
 279           rs6000_ptrace64 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 280                            nr, 0, &buf);
 281         }
 282     }
 283
 284   if (errno)
 285     {
 286       perror (_("ptrace write"));
 287       errno = 0;
 288     }
 289 }
 290
 291 /* Read from the inferior all registers if REGNO == -1 and just register
 292    REGNO otherwise.  */
 293
 294 static void
 295 rs6000_fetch_inferior_registers (struct target_ops *ops,
 296                                  struct regcache *regcache, int regno)
 297 {
 298   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 299   if (regno != -1)
 300     fetch_register (regcache, regno);
 301
 302   else
 303     {
 304       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 305
 306       /* Read 32 general purpose registers.  */
 307       for (regno = tdep->ppc_gp0_regnum;
 308            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 309            regno++)
 310         {
 311           fetch_register (regcache, regno);
 312         }
 313
 314       /* Read general purpose floating point registers.  */
 315       if (tdep->ppc_fp0_regnum >= 0)
 316         for (regno = 0; regno < ppc_num_fprs; regno++)
 317           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 318
 319       /* Read special registers.  */
 320       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 321       fetch_register (regcache, tdep->ppc_ps_regnum);
 322       fetch_register (regcache, tdep->ppc_cr_regnum);
 323       fetch_register (regcache, tdep->ppc_lr_regnum);
 324       fetch_register (regcache, tdep->ppc_ctr_regnum);
 325       fetch_register (regcache, tdep->ppc_xer_regnum);
 326       if (tdep->ppc_fpscr_regnum >= 0)
 327         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 328       if (tdep->ppc_mq_regnum >= 0)
 329         fetch_register (regcache, tdep->ppc_mq_regnum);
 330     }
 331 }
 332
 333 /* Store our register values back into the inferior.
 334    If REGNO is -1, do this for all registers.
 335    Otherwise, REGNO specifies which register (so we can save time).  */
 336
 337 static void
 338 rs6000_store_inferior_registers (struct target_ops *ops,
 339                                  struct regcache *regcache, int regno)
 340 {
 341   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 342   if (regno != -1)
 343     store_register (regcache, regno);
 344
 345   else
 346     {
 347       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 348
 349       /* Write general purpose registers first.  */
 350       for (regno = tdep->ppc_gp0_regnum;
 351            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 352            regno++)
 353         {
 354           store_register (regcache, regno);
 355         }
 356
 357       /* Write floating point registers.  */
 358       if (tdep->ppc_fp0_regnum >= 0)
 359         for (regno = 0; regno < ppc_num_fprs; regno++)
 360           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 361
 362       /* Write special registers.  */
 363       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 364       store_register (regcache, tdep->ppc_ps_regnum);
 365       store_register (regcache, tdep->ppc_cr_regnum);
 366       store_register (regcache, tdep->ppc_lr_regnum);
 367       store_register (regcache, tdep->ppc_ctr_regnum);
 368       store_register (regcache, tdep->ppc_xer_regnum);
 369       if (tdep->ppc_fpscr_regnum >= 0)
 370         store_register (regcache, tdep->ppc_fpscr_regnum);
 371       if (tdep->ppc_mq_regnum >= 0)
 372         store_register (regcache, tdep->ppc_mq_regnum);
 373     }
 374 }
 375
 376 /* Implement the to_xfer_partial target_ops method.  */
 377
 378 static enum target_xfer_status
 379 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 380                      const char *annex, gdb_byte *readbuf,
 381                      const gdb_byte *writebuf,
 382                      ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 383 {
 384   pid_t pid = ptid_get_pid (inferior_ptid);
 385   int arch64 = ARCH64 ();
 386
 387   switch (object)
 388     {
 389     case TARGET_OBJECT_LIBRARIES_AIX:
 390       return rs6000_xfer_shared_libraries (ops, object, annex,
 391                                            readbuf, writebuf,
 392                                            offset, len, xfered_len);
 393     case TARGET_OBJECT_MEMORY:
 394       {
 395         union
 396         {
 397           PTRACE_TYPE_RET word;
 398           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 399         } buffer;
 400         ULONGEST rounded_offset;
 401         LONGEST partial_len;
 402
 403         /* Round the start offset down to the next long word
 404            boundary.  */
 405         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 406
 407         /* Since ptrace will transfer a single word starting at that
 408            rounded_offset the partial_len needs to be adjusted down to
 409            that (remember this function only does a single transfer).
 410            Should the required length be even less, adjust it down
 411            again.  */
 412         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 413         if (partial_len > len)
 414           partial_len = len;
 415
 416         if (writebuf)
 417           {
 418             /* If OFFSET:PARTIAL_LEN is smaller than
 419                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 420                be needed.  Read in the entire word.  */
 421             if (rounded_offset < offset
 422                 || (offset + partial_len
 423                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 424               {
 425                 /* Need part of initial word -- fetch it.  */
 426                 if (arch64)
 427                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 428                                                  rounded_offset, 0, NULL);
 429                 else
 430                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 431                                                  (int *) (uintptr_t)
 432                                                  rounded_offset,
 433                                                  0, NULL);
 434               }
 435
 436             /* Copy data to be written over corresponding part of
 437                buffer.  */
 438             memcpy (buffer.byte + (offset - rounded_offset),
 439                     writebuf, partial_len);
 440
 441             errno = 0;
 442             if (arch64)
 443               rs6000_ptrace64 (PT_WRITE_D, pid,
 444                                rounded_offset, buffer.word, NULL);
 445             else
 446               rs6000_ptrace32 (PT_WRITE_D, pid,
 447                                (int *) (uintptr_t) rounded_offset,
 448                                buffer.word, NULL);
 449             if (errno)
 450               return TARGET_XFER_EOF;
 451           }
 452
 453         if (readbuf)
 454           {
 455             errno = 0;
 456             if (arch64)
 457               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 458                                              rounded_offset, 0, NULL);
 459             else
 460               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 461                                              (int *)(uintptr_t)rounded_offset,
 462                                              0, NULL);
 463             if (errno)
 464               return TARGET_XFER_EOF;
 465
 466             /* Copy appropriate bytes out of the buffer.  */
 467             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 468                     partial_len);
 469           }
 470
 471         *xfered_len = (ULONGEST) partial_len;
 472         return TARGET_XFER_OK;
 473       }
 474
 475     default:
 476       return TARGET_XFER_E_IO;
 477     }
 478 }
 479
 480 /* Wait for the child specified by PTID to do something.  Return the
 481    process ID of the child, or MINUS_ONE_PTID in case of error; store
 482    the status in *OURSTATUS.  */
 483
 484 static ptid_t
 485 rs6000_wait (struct target_ops *ops,
 486              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 487 {
 488   pid_t pid;
 489   int status, save_errno;
 490
 491   do
 492     {
 493       set_sigint_trap ();
 494
 495       do
 496         {
 497           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 498           save_errno = errno;
 499         }
 500       while (pid == -1 && errno == EINTR);
 501
 502       clear_sigint_trap ();
 503
 504       if (pid == -1)
 505         {
 506           fprintf_unfiltered (gdb_stderr,
 507                               _("Child process unexpectedly missing: %s.\n"),
 508                               safe_strerror (save_errno));
 509
 510           /* Claim it exited with unknown signal.  */
 511           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 512           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 513           return inferior_ptid;
 514         }
 515
 516       /* Ignore terminated detached child processes.  */
 517       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 518         pid = -1;
 519     }
 520   while (pid == -1);
 521
 522   /* AIX has a couple of strange returns from wait().  */
 523
 524   /* stop after load" status.  */
 525   if (status == 0x57c)
 526     ourstatus->kind = TARGET_WAITKIND_LOADED;
 527   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 528   else if (status == 0x7f)
 529     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 530   /* A normal waitstatus.  Let the usual macros deal with it.  */
 531   else
 532     store_waitstatus (ourstatus, status);
 533
 534   return pid_to_ptid (pid);
 535 }
 536
 537 /* Execute one dummy breakpoint instruction.  This way we give the kernel
 538    a chance to do some housekeeping and update inferior's internal data,
 539    including u_area.  */
 540
 541 static void
 542 exec_one_dummy_insn (struct regcache *regcache)
 543 {
 544 #define DUMMY_INSN_ADDR AIX_TEXT_SEGMENT_BASE+0x200
 545
 546   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 547   int ret, status, pid;
 548   CORE_ADDR prev_pc;
 549   void *bp;
 550
 551   /* We plant one dummy breakpoint into DUMMY_INSN_ADDR address.  We
 552      assume that this address will never be executed again by the real
 553      code.  */
 554
 555   bp = deprecated_insert_raw_breakpoint (gdbarch, NULL, DUMMY_INSN_ADDR);
 556
 557   /* You might think this could be done with a single ptrace call, and
 558      you'd be correct for just about every platform I've ever worked
 559      on.  However, rs6000-ibm-aix4.1.3 seems to have screwed this up --
 560      the inferior never hits the breakpoint (it's also worth noting
 561      powerpc-ibm-aix4.1.3 works correctly).  */
 562   prev_pc = regcache_read_pc (regcache);
 563   regcache_write_pc (regcache, DUMMY_INSN_ADDR);
 564   if (ARCH64 ())
 565     ret = rs6000_ptrace64 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 566                            1, 0, NULL);
 567   else
 568     ret = rs6000_ptrace32 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 569                            (int *) 1, 0, NULL);
 570
 571   if (ret != 0)
 572     perror (_("pt_continue"));
 573
 574   do
 575     {
 576       pid = waitpid (ptid_get_pid (inferior_ptid), &status, 0);
 577     }
 578   while (pid != ptid_get_pid (inferior_ptid));
 579
 580   regcache_write_pc (regcache, prev_pc);
 581   deprecated_remove_raw_breakpoint (gdbarch, bp);
 582 }
 583 \f
 584
 585 /* Set the current architecture from the host running GDB.  Called when
 586    starting a child process.  */
 587
 588 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 589                                       char *allargs, char **env, int from_tty);
 590 static void
 591 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 592                         char *allargs, char **env, int from_tty)
 593 {
 594   enum bfd_architecture arch;
 595   unsigned long mach;
 596   bfd abfd;
 597   struct gdbarch_info info;
 598
 599   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 600
 601   if (__power_rs ())
 602     {
 603       arch = bfd_arch_rs6000;
 604       mach = bfd_mach_rs6k;
 605     }
 606   else
 607     {
 608       arch = bfd_arch_powerpc;
 609       mach = bfd_mach_ppc;
 610     }
 611
 612   /* FIXME: schauer/2002-02-25:
 613      We don't know if we are executing a 32 or 64 bit executable,
 614      and have no way to pass the proper word size to rs6000_gdbarch_init.
 615      So we have to avoid switching to a new architecture, if the architecture
 616      matches already.
 617      Blindly calling rs6000_gdbarch_init used to work in older versions of
 618      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 619      determine the wordsize.  */
 620   if (exec_bfd)
 621     {
 622       const struct bfd_arch_info *exec_bfd_arch_info;
 623
 624       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 625       if (arch == exec_bfd_arch_info->arch)
 626         return;
 627     }
 628
 629   bfd_default_set_arch_mach (&abfd, arch, mach);
 630
 631   gdbarch_info_init (&info);
 632   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 633   info.abfd = exec_bfd;
 634
 635   if (!gdbarch_update_p (info))
 636     internal_error (__FILE__, __LINE__,
 637                     _("rs6000_create_inferior: failed "
 638                       "to select architecture"));
 639 }
 640 \f
 641
 642 /* Shared Object support.  */
 643
 644 /* Return the LdInfo data for the given process.  Raises an error
 645    if the data could not be obtained.
 646
 647    The returned value must be deallocated after use.  */
 648
 649 static gdb_byte *
 650 rs6000_ptrace_ldinfo (ptid_t ptid)
 651 {
 652   const int pid = ptid_get_pid (ptid);
 653   int ldi_size = 1024;
 654   gdb_byte *ldi = xmalloc (ldi_size);
 655   int rc = -1;
 656
 657   while (1)
 658     {
 659       if (ARCH64 ())
 660         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 661                               NULL);
 662       else
 663         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 664
 665       if (rc != -1)
 666         break; /* Success, we got the entire ld_info data.  */
 667
 668       if (errno != ENOMEM)
 669         perror_with_name (_("ptrace ldinfo"));
 670
 671       /* ldi is not big enough.  Double it and try again.  */
 672       ldi_size *= 2;
 673       ldi = xrealloc (ldi, ldi_size);
 674     }
 675
 676   return ldi;
 677 }
 678
 679 /* Implement the to_xfer_partial target_ops method for
 680    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 681
 682 static enum target_xfer_status
 683 rs6000_xfer_shared_libraries
 684   (struct target_ops *ops, enum target_object object,
 685    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 686    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 687 {
 688   gdb_byte *ldi_buf;
 689   ULONGEST result;
 690   struct cleanup *cleanup;
 691
 692   /* This function assumes that it is being run with a live process.
 693      Core files are handled via gdbarch.  */
 694   gdb_assert (target_has_execution);
 695
 696   if (writebuf)
 697     return TARGET_XFER_E_IO;
 698
 699   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 700   gdb_assert (ldi_buf != NULL);
 701   cleanup = make_cleanup (xfree, ldi_buf);
 702   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 703                                       readbuf, offset, len, 1);
 704   xfree (ldi_buf);
 705
 706   do_cleanups (cleanup);
 707
 708   if (result == 0)
 709     return TARGET_XFER_EOF;
 710   else
 711     {
 712       *xfered_len = result;
 713       return TARGET_XFER_OK;
 714     }
 715 }
 716
 717 void _initialize_rs6000_nat (void);
 718
 719 void
 720 _initialize_rs6000_nat (void)
 721 {
 722   struct target_ops *t;
 723
 724   t = inf_ptrace_target ();
 725   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 726   t->to_store_registers = rs6000_store_inferior_registers;
 727   t->to_xfer_partial = rs6000_xfer_partial;
 728
 729   super_create_inferior = t->to_create_inferior;
 730   t->to_create_inferior = rs6000_create_inferior;
 731
 732   t->to_wait = rs6000_wait;
 733
 734   add_target (t);
 735 }