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 #include <errno.h>
  50
  51 #include <a.out.h>
  52 #include <sys/file.h>
  53 #include <sys/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 target_xfer_partial_ftype rs6000_xfer_shared_libraries;
  83
  84 /* Given REGNO, a gdb register number, return the corresponding
  85    number suitable for use as a ptrace() parameter.  Return -1 if
  86    there's no suitable mapping.  Also, set the int pointed to by
  87    ISFLOAT to indicate whether REGNO is a floating point register.  */
  88
  89 static int
  90 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  91 {
  92   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  93
  94   *isfloat = 0;
  95   if (tdep->ppc_gp0_regnum <= regno
  96       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
  97     return regno;
  98   else if (tdep->ppc_fp0_regnum >= 0
  99            && tdep->ppc_fp0_regnum <= regno
 100            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 101     {
 102       *isfloat = 1;
 103       return regno - tdep->ppc_fp0_regnum + FPR0;
 104     }
 105   else if (regno == gdbarch_pc_regnum (gdbarch))
 106     return IAR;
 107   else if (regno == tdep->ppc_ps_regnum)
 108     return MSR;
 109   else if (regno == tdep->ppc_cr_regnum)
 110     return CR;
 111   else if (regno == tdep->ppc_lr_regnum)
 112     return LR;
 113   else if (regno == tdep->ppc_ctr_regnum)
 114     return CTR;
 115   else if (regno == tdep->ppc_xer_regnum)
 116     return XER;
 117   else if (tdep->ppc_fpscr_regnum >= 0
 118            && regno == tdep->ppc_fpscr_regnum)
 119     return FPSCR;
 120   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 121     return MQ;
 122   else
 123     return -1;
 124 }
 125
 126 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 127
 128 static int
 129 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 130 {
 131 #ifdef HAVE_PTRACE64
 132   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 133 #else
 134   int ret = ptrace (req, id, (int *)addr, data, buf);
 135 #endif
 136 #if 0
 137   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 138           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 139 #endif
 140   return ret;
 141 }
 142
 143 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 144
 145 static int
 146 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 147 {
 148 #ifdef ARCH3264
 149 #  ifdef HAVE_PTRACE64
 150   int ret = ptrace64 (req, id, addr, data, buf);
 151 #  else
 152   int ret = ptracex (req, id, addr, data, buf);
 153 #  endif
 154 #else
 155   int ret = 0;
 156 #endif
 157 #if 0
 158   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 159           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 160 #endif
 161   return ret;
 162 }
 163
 164 /* Fetch register REGNO from the inferior.  */
 165
 166 static void
 167 fetch_register (struct regcache *regcache, int regno)
 168 {
 169   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 170   int addr[MAX_REGISTER_SIZE];
 171   int nr, isfloat;
 172
 173   /* Retrieved values may be -1, so infer errors from errno.  */
 174   errno = 0;
 175
 176   nr = regmap (gdbarch, regno, &isfloat);
 177
 178   /* Floating-point registers.  */
 179   if (isfloat)
 180     rs6000_ptrace32 (PT_READ_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 181
 182   /* Bogus register number.  */
 183   else if (nr < 0)
 184     {
 185       if (regno >= gdbarch_num_regs (gdbarch))
 186         fprintf_unfiltered (gdb_stderr,
 187                             "gdb error: register no %d not implemented.\n",
 188                             regno);
 189       return;
 190     }
 191
 192   /* Fixed-point registers.  */
 193   else
 194     {
 195       if (!ARCH64 ())
 196         *addr = rs6000_ptrace32 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 197                                  (int *) nr, 0, 0);
 198       else
 199         {
 200           /* PT_READ_GPR requires the buffer parameter to point to long long,
 201              even if the register is really only 32 bits.  */
 202           long long buf;
 203           rs6000_ptrace64 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 204                            nr, 0, &buf);
 205           if (register_size (gdbarch, regno) == 8)
 206             memcpy (addr, &buf, 8);
 207           else
 208             *addr = buf;
 209         }
 210     }
 211
 212   if (!errno)
 213     regcache_raw_supply (regcache, regno, (char *) addr);
 214   else
 215     {
 216 #if 0
 217       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 218       perror (_("ptrace read"));
 219 #endif
 220       errno = 0;
 221     }
 222 }
 223
 224 /* Store register REGNO back into the inferior.  */
 225
 226 static void
 227 store_register (struct regcache *regcache, int regno)
 228 {
 229   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 230   int addr[MAX_REGISTER_SIZE];
 231   int nr, isfloat;
 232
 233   /* Fetch the register's value from the register cache.  */
 234   regcache_raw_collect (regcache, regno, addr);
 235
 236   /* -1 can be a successful return value, so infer errors from errno.  */
 237   errno = 0;
 238
 239   nr = regmap (gdbarch, regno, &isfloat);
 240
 241   /* Floating-point registers.  */
 242   if (isfloat)
 243     rs6000_ptrace32 (PT_WRITE_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 244
 245   /* Bogus register number.  */
 246   else if (nr < 0)
 247     {
 248       if (regno >= gdbarch_num_regs (gdbarch))
 249         fprintf_unfiltered (gdb_stderr,
 250                             "gdb error: register no %d not implemented.\n",
 251                             regno);
 252     }
 253
 254   /* Fixed-point registers.  */
 255   else
 256     {
 257       if (regno == gdbarch_sp_regnum (gdbarch))
 258         /* Execute one dummy instruction (which is a breakpoint) in inferior
 259            process to give kernel a chance to do internal housekeeping.
 260            Otherwise the following ptrace(2) calls will mess up user stack
 261            since kernel will get confused about the bottom of the stack
 262            (%sp).  */
 263         exec_one_dummy_insn (regcache);
 264
 265       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 266          the register's value is passed by value, but for 64-bit inferiors,
 267          the address of a buffer containing the value is passed.  */
 268       if (!ARCH64 ())
 269         rs6000_ptrace32 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 270                          (int *) nr, *addr, 0);
 271       else
 272         {
 273           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 274              area, even if the register is really only 32 bits.  */
 275           long long buf;
 276           if (register_size (gdbarch, regno) == 8)
 277             memcpy (&buf, addr, 8);
 278           else
 279             buf = *addr;
 280           rs6000_ptrace64 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 281                            nr, 0, &buf);
 282         }
 283     }
 284
 285   if (errno)
 286     {
 287       perror (_("ptrace write"));
 288       errno = 0;
 289     }
 290 }
 291
 292 /* Read from the inferior all registers if REGNO == -1 and just register
 293    REGNO otherwise.  */
 294
 295 static void
 296 rs6000_fetch_inferior_registers (struct target_ops *ops,
 297                                  struct regcache *regcache, int regno)
 298 {
 299   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 300   if (regno != -1)
 301     fetch_register (regcache, regno);
 302
 303   else
 304     {
 305       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 306
 307       /* Read 32 general purpose registers.  */
 308       for (regno = tdep->ppc_gp0_regnum;
 309            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 310            regno++)
 311         {
 312           fetch_register (regcache, regno);
 313         }
 314
 315       /* Read general purpose floating point registers.  */
 316       if (tdep->ppc_fp0_regnum >= 0)
 317         for (regno = 0; regno < ppc_num_fprs; regno++)
 318           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 319
 320       /* Read special registers.  */
 321       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 322       fetch_register (regcache, tdep->ppc_ps_regnum);
 323       fetch_register (regcache, tdep->ppc_cr_regnum);
 324       fetch_register (regcache, tdep->ppc_lr_regnum);
 325       fetch_register (regcache, tdep->ppc_ctr_regnum);
 326       fetch_register (regcache, tdep->ppc_xer_regnum);
 327       if (tdep->ppc_fpscr_regnum >= 0)
 328         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 329       if (tdep->ppc_mq_regnum >= 0)
 330         fetch_register (regcache, tdep->ppc_mq_regnum);
 331     }
 332 }
 333
 334 /* Store our register values back into the inferior.
 335    If REGNO is -1, do this for all registers.
 336    Otherwise, REGNO specifies which register (so we can save time).  */
 337
 338 static void
 339 rs6000_store_inferior_registers (struct target_ops *ops,
 340                                  struct regcache *regcache, int regno)
 341 {
 342   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 343   if (regno != -1)
 344     store_register (regcache, regno);
 345
 346   else
 347     {
 348       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 349
 350       /* Write general purpose registers first.  */
 351       for (regno = tdep->ppc_gp0_regnum;
 352            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 353            regno++)
 354         {
 355           store_register (regcache, regno);
 356         }
 357
 358       /* Write floating point registers.  */
 359       if (tdep->ppc_fp0_regnum >= 0)
 360         for (regno = 0; regno < ppc_num_fprs; regno++)
 361           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 362
 363       /* Write special registers.  */
 364       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 365       store_register (regcache, tdep->ppc_ps_regnum);
 366       store_register (regcache, tdep->ppc_cr_regnum);
 367       store_register (regcache, tdep->ppc_lr_regnum);
 368       store_register (regcache, tdep->ppc_ctr_regnum);
 369       store_register (regcache, tdep->ppc_xer_regnum);
 370       if (tdep->ppc_fpscr_regnum >= 0)
 371         store_register (regcache, tdep->ppc_fpscr_regnum);
 372       if (tdep->ppc_mq_regnum >= 0)
 373         store_register (regcache, tdep->ppc_mq_regnum);
 374     }
 375 }
 376
 377 /* Implement the to_xfer_partial target_ops method.  */
 378
 379 static enum target_xfer_status
 380 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 381                      const char *annex, gdb_byte *readbuf,
 382                      const gdb_byte *writebuf,
 383                      ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 384 {
 385   pid_t pid = ptid_get_pid (inferior_ptid);
 386   int arch64 = ARCH64 ();
 387
 388   switch (object)
 389     {
 390     case TARGET_OBJECT_LIBRARIES_AIX:
 391       return rs6000_xfer_shared_libraries (ops, object, annex,
 392                                            readbuf, writebuf,
 393                                            offset, len, xfered_len);
 394     case TARGET_OBJECT_MEMORY:
 395       {
 396         union
 397         {
 398           PTRACE_TYPE_RET word;
 399           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 400         } buffer;
 401         ULONGEST rounded_offset;
 402         LONGEST partial_len;
 403
 404         /* Round the start offset down to the next long word
 405            boundary.  */
 406         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 407
 408         /* Since ptrace will transfer a single word starting at that
 409            rounded_offset the partial_len needs to be adjusted down to
 410            that (remember this function only does a single transfer).
 411            Should the required length be even less, adjust it down
 412            again.  */
 413         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 414         if (partial_len > len)
 415           partial_len = len;
 416
 417         if (writebuf)
 418           {
 419             /* If OFFSET:PARTIAL_LEN is smaller than
 420                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 421                be needed.  Read in the entire word.  */
 422             if (rounded_offset < offset
 423                 || (offset + partial_len
 424                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 425               {
 426                 /* Need part of initial word -- fetch it.  */
 427                 if (arch64)
 428                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 429                                                  rounded_offset, 0, NULL);
 430                 else
 431                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 432                                                  (int *) (uintptr_t)
 433                                                  rounded_offset,
 434                                                  0, NULL);
 435               }
 436
 437             /* Copy data to be written over corresponding part of
 438                buffer.  */
 439             memcpy (buffer.byte + (offset - rounded_offset),
 440                     writebuf, partial_len);
 441
 442             errno = 0;
 443             if (arch64)
 444               rs6000_ptrace64 (PT_WRITE_D, pid,
 445                                rounded_offset, buffer.word, NULL);
 446             else
 447               rs6000_ptrace32 (PT_WRITE_D, pid,
 448                                (int *) (uintptr_t) rounded_offset,
 449                                buffer.word, NULL);
 450             if (errno)
 451               return TARGET_XFER_EOF;
 452           }
 453
 454         if (readbuf)
 455           {
 456             errno = 0;
 457             if (arch64)
 458               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 459                                              rounded_offset, 0, NULL);
 460             else
 461               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 462                                              (int *)(uintptr_t)rounded_offset,
 463                                              0, NULL);
 464             if (errno)
 465               return TARGET_XFER_EOF;
 466
 467             /* Copy appropriate bytes out of the buffer.  */
 468             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 469                     partial_len);
 470           }
 471
 472         *xfered_len = (ULONGEST) partial_len;
 473         return TARGET_XFER_OK;
 474       }
 475
 476     default:
 477       return TARGET_XFER_E_IO;
 478     }
 479 }
 480
 481 /* Wait for the child specified by PTID to do something.  Return the
 482    process ID of the child, or MINUS_ONE_PTID in case of error; store
 483    the status in *OURSTATUS.  */
 484
 485 static ptid_t
 486 rs6000_wait (struct target_ops *ops,
 487              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 488 {
 489   pid_t pid;
 490   int status, save_errno;
 491
 492   do
 493     {
 494       set_sigint_trap ();
 495
 496       do
 497         {
 498           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 499           save_errno = errno;
 500         }
 501       while (pid == -1 && errno == EINTR);
 502
 503       clear_sigint_trap ();
 504
 505       if (pid == -1)
 506         {
 507           fprintf_unfiltered (gdb_stderr,
 508                               _("Child process unexpectedly missing: %s.\n"),
 509                               safe_strerror (save_errno));
 510
 511           /* Claim it exited with unknown signal.  */
 512           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 513           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 514           return inferior_ptid;
 515         }
 516
 517       /* Ignore terminated detached child processes.  */
 518       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 519         pid = -1;
 520     }
 521   while (pid == -1);
 522
 523   /* AIX has a couple of strange returns from wait().  */
 524
 525   /* stop after load" status.  */
 526   if (status == 0x57c)
 527     ourstatus->kind = TARGET_WAITKIND_LOADED;
 528   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 529   else if (status == 0x7f)
 530     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 531   /* A normal waitstatus.  Let the usual macros deal with it.  */
 532   else
 533     store_waitstatus (ourstatus, status);
 534
 535   return pid_to_ptid (pid);
 536 }
 537
 538 /* Execute one dummy breakpoint instruction.  This way we give the kernel
 539    a chance to do some housekeeping and update inferior's internal data,
 540    including u_area.  */
 541
 542 static void
 543 exec_one_dummy_insn (struct regcache *regcache)
 544 {
 545 #define DUMMY_INSN_ADDR AIX_TEXT_SEGMENT_BASE+0x200
 546
 547   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 548   int ret, status, pid;
 549   CORE_ADDR prev_pc;
 550   void *bp;
 551
 552   /* We plant one dummy breakpoint into DUMMY_INSN_ADDR address.  We
 553      assume that this address will never be executed again by the real
 554      code.  */
 555
 556   bp = deprecated_insert_raw_breakpoint (gdbarch, NULL, DUMMY_INSN_ADDR);
 557
 558   /* You might think this could be done with a single ptrace call, and
 559      you'd be correct for just about every platform I've ever worked
 560      on.  However, rs6000-ibm-aix4.1.3 seems to have screwed this up --
 561      the inferior never hits the breakpoint (it's also worth noting
 562      powerpc-ibm-aix4.1.3 works correctly).  */
 563   prev_pc = regcache_read_pc (regcache);
 564   regcache_write_pc (regcache, DUMMY_INSN_ADDR);
 565   if (ARCH64 ())
 566     ret = rs6000_ptrace64 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 567                            1, 0, NULL);
 568   else
 569     ret = rs6000_ptrace32 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 570                            (int *) 1, 0, NULL);
 571
 572   if (ret != 0)
 573     perror (_("pt_continue"));
 574
 575   do
 576     {
 577       pid = waitpid (ptid_get_pid (inferior_ptid), &status, 0);
 578     }
 579   while (pid != ptid_get_pid (inferior_ptid));
 580
 581   regcache_write_pc (regcache, prev_pc);
 582   deprecated_remove_raw_breakpoint (gdbarch, bp);
 583 }
 584 \f
 585
 586 /* Set the current architecture from the host running GDB.  Called when
 587    starting a child process.  */
 588
 589 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 590                                       char *allargs, char **env, int from_tty);
 591 static void
 592 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 593                         char *allargs, char **env, int from_tty)
 594 {
 595   enum bfd_architecture arch;
 596   unsigned long mach;
 597   bfd abfd;
 598   struct gdbarch_info info;
 599
 600   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 601
 602   if (__power_rs ())
 603     {
 604       arch = bfd_arch_rs6000;
 605       mach = bfd_mach_rs6k;
 606     }
 607   else
 608     {
 609       arch = bfd_arch_powerpc;
 610       mach = bfd_mach_ppc;
 611     }
 612
 613   /* FIXME: schauer/2002-02-25:
 614      We don't know if we are executing a 32 or 64 bit executable,
 615      and have no way to pass the proper word size to rs6000_gdbarch_init.
 616      So we have to avoid switching to a new architecture, if the architecture
 617      matches already.
 618      Blindly calling rs6000_gdbarch_init used to work in older versions of
 619      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 620      determine the wordsize.  */
 621   if (exec_bfd)
 622     {
 623       const struct bfd_arch_info *exec_bfd_arch_info;
 624
 625       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 626       if (arch == exec_bfd_arch_info->arch)
 627         return;
 628     }
 629
 630   bfd_default_set_arch_mach (&abfd, arch, mach);
 631
 632   gdbarch_info_init (&info);
 633   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 634   info.abfd = exec_bfd;
 635
 636   if (!gdbarch_update_p (info))
 637     internal_error (__FILE__, __LINE__,
 638                     _("rs6000_create_inferior: failed "
 639                       "to select architecture"));
 640 }
 641 \f
 642
 643 /* Shared Object support.  */
 644
 645 /* Return the LdInfo data for the given process.  Raises an error
 646    if the data could not be obtained.
 647
 648    The returned value must be deallocated after use.  */
 649
 650 static gdb_byte *
 651 rs6000_ptrace_ldinfo (ptid_t ptid)
 652 {
 653   const int pid = ptid_get_pid (ptid);
 654   int ldi_size = 1024;
 655   gdb_byte *ldi = xmalloc (ldi_size);
 656   int rc = -1;
 657
 658   while (1)
 659     {
 660       if (ARCH64 ())
 661         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 662                               NULL);
 663       else
 664         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 665
 666       if (rc != -1)
 667         break; /* Success, we got the entire ld_info data.  */
 668
 669       if (errno != ENOMEM)
 670         perror_with_name (_("ptrace ldinfo"));
 671
 672       /* ldi is not big enough.  Double it and try again.  */
 673       ldi_size *= 2;
 674       ldi = xrealloc (ldi, ldi_size);
 675     }
 676
 677   return ldi;
 678 }
 679
 680 /* Implement the to_xfer_partial target_ops method for
 681    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 682
 683 static enum target_xfer_status
 684 rs6000_xfer_shared_libraries
 685   (struct target_ops *ops, enum target_object object,
 686    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 687    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 688 {
 689   gdb_byte *ldi_buf;
 690   ULONGEST result;
 691   struct cleanup *cleanup;
 692
 693   /* This function assumes that it is being run with a live process.
 694      Core files are handled via gdbarch.  */
 695   gdb_assert (target_has_execution);
 696
 697   if (writebuf)
 698     return TARGET_XFER_E_IO;
 699
 700   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 701   gdb_assert (ldi_buf != NULL);
 702   cleanup = make_cleanup (xfree, ldi_buf);
 703   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 704                                       readbuf, offset, len, 1);
 705   xfree (ldi_buf);
 706
 707   do_cleanups (cleanup);
 708
 709   if (result == 0)
 710     return TARGET_XFER_EOF;
 711   else
 712     {
 713       *xfered_len = result;
 714       return TARGET_XFER_OK;
 715     }
 716 }
 717
 718 void _initialize_rs6000_nat (void);
 719
 720 void
 721 _initialize_rs6000_nat (void)
 722 {
 723   struct target_ops *t;
 724
 725   t = inf_ptrace_target ();
 726   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 727   t->to_store_registers = rs6000_store_inferior_registers;
 728   t->to_xfer_partial = rs6000_xfer_partial;
 729
 730   super_create_inferior = t->to_create_inferior;
 731   t->to_create_inferior = rs6000_create_inferior;
 732
 733   t->to_wait = rs6000_wait;
 734
 735   add_target (t);
 736 }