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
 378 /* Attempt a transfer all LEN bytes starting at OFFSET between the
 379    inferior's OBJECT:ANNEX space and GDB's READBUF/WRITEBUF buffer.
 380    Return the number of bytes actually transferred.  */
 381
 382 static LONGEST
 383 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 384                      const char *annex, gdb_byte *readbuf,
 385                      const gdb_byte *writebuf,
 386                      ULONGEST offset, LONGEST len)
 387 {
 388   pid_t pid = ptid_get_pid (inferior_ptid);
 389   int arch64 = ARCH64 ();
 390
 391   switch (object)
 392     {
 393     case TARGET_OBJECT_LIBRARIES_AIX:
 394       return rs6000_xfer_shared_libraries (ops, object, annex,
 395                                            readbuf, writebuf,
 396                                            offset, len);
 397     case TARGET_OBJECT_MEMORY:
 398       {
 399         union
 400         {
 401           PTRACE_TYPE_RET word;
 402           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 403         } buffer;
 404         ULONGEST rounded_offset;
 405         LONGEST partial_len;
 406
 407         /* Round the start offset down to the next long word
 408            boundary.  */
 409         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 410
 411         /* Since ptrace will transfer a single word starting at that
 412            rounded_offset the partial_len needs to be adjusted down to
 413            that (remember this function only does a single transfer).
 414            Should the required length be even less, adjust it down
 415            again.  */
 416         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 417         if (partial_len > len)
 418           partial_len = len;
 419
 420         if (writebuf)
 421           {
 422             /* If OFFSET:PARTIAL_LEN is smaller than
 423                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 424                be needed.  Read in the entire word.  */
 425             if (rounded_offset < offset
 426                 || (offset + partial_len
 427                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 428               {
 429                 /* Need part of initial word -- fetch it.  */
 430                 if (arch64)
 431                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 432                                                  rounded_offset, 0, NULL);
 433                 else
 434                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 435                                                  (int *) (uintptr_t)
 436                                                  rounded_offset,
 437                                                  0, NULL);
 438               }
 439
 440             /* Copy data to be written over corresponding part of
 441                buffer.  */
 442             memcpy (buffer.byte + (offset - rounded_offset),
 443                     writebuf, partial_len);
 444
 445             errno = 0;
 446             if (arch64)
 447               rs6000_ptrace64 (PT_WRITE_D, pid,
 448                                rounded_offset, buffer.word, NULL);
 449             else
 450               rs6000_ptrace32 (PT_WRITE_D, pid,
 451                                (int *) (uintptr_t) rounded_offset,
 452                                buffer.word, NULL);
 453             if (errno)
 454               return 0;
 455           }
 456
 457         if (readbuf)
 458           {
 459             errno = 0;
 460             if (arch64)
 461               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 462                                              rounded_offset, 0, NULL);
 463             else
 464               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 465                                              (int *)(uintptr_t)rounded_offset,
 466                                              0, NULL);
 467             if (errno)
 468               return 0;
 469
 470             /* Copy appropriate bytes out of the buffer.  */
 471             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 472                     partial_len);
 473           }
 474
 475         return partial_len;
 476       }
 477
 478     default:
 479       return -1;
 480     }
 481 }
 482
 483 /* Wait for the child specified by PTID to do something.  Return the
 484    process ID of the child, or MINUS_ONE_PTID in case of error; store
 485    the status in *OURSTATUS.  */
 486
 487 static ptid_t
 488 rs6000_wait (struct target_ops *ops,
 489              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 490 {
 491   pid_t pid;
 492   int status, save_errno;
 493
 494   do
 495     {
 496       set_sigint_trap ();
 497
 498       do
 499         {
 500           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 501           save_errno = errno;
 502         }
 503       while (pid == -1 && errno == EINTR);
 504
 505       clear_sigint_trap ();
 506
 507       if (pid == -1)
 508         {
 509           fprintf_unfiltered (gdb_stderr,
 510                               _("Child process unexpectedly missing: %s.\n"),
 511                               safe_strerror (save_errno));
 512
 513           /* Claim it exited with unknown signal.  */
 514           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 515           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 516           return inferior_ptid;
 517         }
 518
 519       /* Ignore terminated detached child processes.  */
 520       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 521         pid = -1;
 522     }
 523   while (pid == -1);
 524
 525   /* AIX has a couple of strange returns from wait().  */
 526
 527   /* stop after load" status.  */
 528   if (status == 0x57c)
 529     ourstatus->kind = TARGET_WAITKIND_LOADED;
 530   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 531   else if (status == 0x7f)
 532     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 533   /* A normal waitstatus.  Let the usual macros deal with it.  */
 534   else
 535     store_waitstatus (ourstatus, status);
 536
 537   return pid_to_ptid (pid);
 538 }
 539
 540 /* Execute one dummy breakpoint instruction.  This way we give the kernel
 541    a chance to do some housekeeping and update inferior's internal data,
 542    including u_area.  */
 543
 544 static void
 545 exec_one_dummy_insn (struct regcache *regcache)
 546 {
 547 #define DUMMY_INSN_ADDR AIX_TEXT_SEGMENT_BASE+0x200
 548
 549   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 550   int ret, status, pid;
 551   CORE_ADDR prev_pc;
 552   void *bp;
 553
 554   /* We plant one dummy breakpoint into DUMMY_INSN_ADDR address.  We
 555      assume that this address will never be executed again by the real
 556      code.  */
 557
 558   bp = deprecated_insert_raw_breakpoint (gdbarch, NULL, DUMMY_INSN_ADDR);
 559
 560   /* You might think this could be done with a single ptrace call, and
 561      you'd be correct for just about every platform I've ever worked
 562      on.  However, rs6000-ibm-aix4.1.3 seems to have screwed this up --
 563      the inferior never hits the breakpoint (it's also worth noting
 564      powerpc-ibm-aix4.1.3 works correctly).  */
 565   prev_pc = regcache_read_pc (regcache);
 566   regcache_write_pc (regcache, DUMMY_INSN_ADDR);
 567   if (ARCH64 ())
 568     ret = rs6000_ptrace64 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 569                            1, 0, NULL);
 570   else
 571     ret = rs6000_ptrace32 (PT_CONTINUE, ptid_get_pid (inferior_ptid),
 572                            (int *) 1, 0, NULL);
 573
 574   if (ret != 0)
 575     perror (_("pt_continue"));
 576
 577   do
 578     {
 579       pid = waitpid (ptid_get_pid (inferior_ptid), &status, 0);
 580     }
 581   while (pid != ptid_get_pid (inferior_ptid));
 582
 583   regcache_write_pc (regcache, prev_pc);
 584   deprecated_remove_raw_breakpoint (gdbarch, bp);
 585 }
 586 \f
 587
 588 /* Set the current architecture from the host running GDB.  Called when
 589    starting a child process.  */
 590
 591 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 592                                       char *allargs, char **env, int from_tty);
 593 static void
 594 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 595                         char *allargs, char **env, int from_tty)
 596 {
 597   enum bfd_architecture arch;
 598   unsigned long mach;
 599   bfd abfd;
 600   struct gdbarch_info info;
 601
 602   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 603
 604   if (__power_rs ())
 605     {
 606       arch = bfd_arch_rs6000;
 607       mach = bfd_mach_rs6k;
 608     }
 609   else
 610     {
 611       arch = bfd_arch_powerpc;
 612       mach = bfd_mach_ppc;
 613     }
 614
 615   /* FIXME: schauer/2002-02-25:
 616      We don't know if we are executing a 32 or 64 bit executable,
 617      and have no way to pass the proper word size to rs6000_gdbarch_init.
 618      So we have to avoid switching to a new architecture, if the architecture
 619      matches already.
 620      Blindly calling rs6000_gdbarch_init used to work in older versions of
 621      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 622      determine the wordsize.  */
 623   if (exec_bfd)
 624     {
 625       const struct bfd_arch_info *exec_bfd_arch_info;
 626
 627       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 628       if (arch == exec_bfd_arch_info->arch)
 629         return;
 630     }
 631
 632   bfd_default_set_arch_mach (&abfd, arch, mach);
 633
 634   gdbarch_info_init (&info);
 635   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 636   info.abfd = exec_bfd;
 637
 638   if (!gdbarch_update_p (info))
 639     internal_error (__FILE__, __LINE__,
 640                     _("rs6000_create_inferior: failed "
 641                       "to select architecture"));
 642 }
 643 \f
 644
 645 /* Shared Object support.  */
 646
 647 /* Return the LdInfo data for the given process.  Raises an error
 648    if the data could not be obtained.
 649
 650    The returned value must be deallocated after use.  */
 651
 652 static gdb_byte *
 653 rs6000_ptrace_ldinfo (ptid_t ptid)
 654 {
 655   const int pid = ptid_get_pid (ptid);
 656   int ldi_size = 1024;
 657   gdb_byte *ldi = xmalloc (ldi_size);
 658   int rc = -1;
 659
 660   while (1)
 661     {
 662       if (ARCH64 ())
 663         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 664                               NULL);
 665       else
 666         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 667
 668       if (rc != -1)
 669         break; /* Success, we got the entire ld_info data.  */
 670
 671       if (errno != ENOMEM)
 672         perror_with_name (_("ptrace ldinfo"));
 673
 674       /* ldi is not big enough.  Double it and try again.  */
 675       ldi_size *= 2;
 676       ldi = xrealloc (ldi, ldi_size);
 677     }
 678
 679   return ldi;
 680 }
 681
 682 /* Implement the to_xfer_partial target_ops method for
 683    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 684
 685 static LONGEST
 686 rs6000_xfer_shared_libraries
 687   (struct target_ops *ops, enum target_object object,
 688    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 689    ULONGEST offset, LONGEST len)
 690 {
 691   gdb_byte *ldi_buf;
 692   ULONGEST result;
 693   struct cleanup *cleanup;
 694
 695   /* This function assumes that it is being run with a live process.
 696      Core files are handled via gdbarch.  */
 697   gdb_assert (target_has_execution);
 698
 699   if (writebuf)
 700     return -1;
 701
 702   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 703   gdb_assert (ldi_buf != NULL);
 704   cleanup = make_cleanup (xfree, ldi_buf);
 705   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 706                                       readbuf, offset, len, 1);
 707   xfree (ldi_buf);
 708
 709   do_cleanups (cleanup);
 710   return result;
 711 }
 712
 713 void _initialize_rs6000_nat (void);
 714
 715 void
 716 _initialize_rs6000_nat (void)
 717 {
 718   struct target_ops *t;
 719
 720   t = inf_ptrace_target ();
 721   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 722   t->to_store_registers = rs6000_store_inferior_registers;
 723   t->to_xfer_partial = rs6000_xfer_partial;
 724
 725   super_create_inferior = t->to_create_inferior;
 726   t->to_create_inferior = rs6000_create_inferior;
 727
 728   t->to_wait = rs6000_wait;
 729
 730   add_target (t);
 731 }