gdb/rs6000-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2016 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 "bfd.h"
  27 #include "gdb-stabs.h"
  28 #include "regcache.h"
  29 #include "arch-utils.h"
  30 #include "inf-child.h"
  31 #include "inf-ptrace.h"
  32 #include "ppc-tdep.h"
  33 #include "rs6000-tdep.h"
  34 #include "rs6000-aix-tdep.h"
  35 #include "exec.h"
  36 #include "observer.h"
  37 #include "xcoffread.h"
  38
  39 #include <sys/ptrace.h>
  40 #include <sys/reg.h>
  41
  42 #include <sys/dir.h>
  43 #include <sys/user.h>
  44 #include <signal.h>
  45 #include <sys/ioctl.h>
  46 #include <fcntl.h>
  47
  48 #include <a.out.h>
  49 #include <sys/file.h>
  50 #include <sys/stat.h>
  51 #include "gdb_bfd.h"
  52 #include <sys/core.h>
  53 #define __LDINFO_PTRACE32__     /* for __ld_info32 */
  54 #define __LDINFO_PTRACE64__     /* for __ld_info64 */
  55 #include <sys/ldr.h>
  56 #include <sys/systemcfg.h>
  57
  58 /* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
  59    debugging 32-bit and 64-bit processes.  Define a typedef and macros for
  60    accessing fields in the appropriate structures.  */
  61
  62 /* In 32-bit compilation mode (which is the only mode from which ptrace()
  63    works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */
  64
  65 #if defined (__ld_info32) || defined (__ld_info64)
  66 # define ARCH3264
  67 #endif
  68
  69 /* Return whether the current architecture is 64-bit.  */
  70
  71 #ifndef ARCH3264
  72 # define ARCH64() 0
  73 #else
  74 # define ARCH64() (register_size (target_gdbarch (), 0) == 8)
  75 #endif
  76
  77 static target_xfer_partial_ftype rs6000_xfer_shared_libraries;
  78
  79 /* Given REGNO, a gdb register number, return the corresponding
  80    number suitable for use as a ptrace() parameter.  Return -1 if
  81    there's no suitable mapping.  Also, set the int pointed to by
  82    ISFLOAT to indicate whether REGNO is a floating point register.  */
  83
  84 static int
  85 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  86 {
  87   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  88
  89   *isfloat = 0;
  90   if (tdep->ppc_gp0_regnum <= regno
  91       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
  92     return regno;
  93   else if (tdep->ppc_fp0_regnum >= 0
  94            && tdep->ppc_fp0_regnum <= regno
  95            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
  96     {
  97       *isfloat = 1;
  98       return regno - tdep->ppc_fp0_regnum + FPR0;
  99     }
 100   else if (regno == gdbarch_pc_regnum (gdbarch))
 101     return IAR;
 102   else if (regno == tdep->ppc_ps_regnum)
 103     return MSR;
 104   else if (regno == tdep->ppc_cr_regnum)
 105     return CR;
 106   else if (regno == tdep->ppc_lr_regnum)
 107     return LR;
 108   else if (regno == tdep->ppc_ctr_regnum)
 109     return CTR;
 110   else if (regno == tdep->ppc_xer_regnum)
 111     return XER;
 112   else if (tdep->ppc_fpscr_regnum >= 0
 113            && regno == tdep->ppc_fpscr_regnum)
 114     return FPSCR;
 115   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 116     return MQ;
 117   else
 118     return -1;
 119 }
 120
 121 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 122
 123 static int
 124 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 125 {
 126 #ifdef HAVE_PTRACE64
 127   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 128 #else
 129   int ret = ptrace (req, id, (int *)addr, data, buf);
 130 #endif
 131 #if 0
 132   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 133           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 134 #endif
 135   return ret;
 136 }
 137
 138 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 139
 140 static int
 141 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 142 {
 143 #ifdef ARCH3264
 144 #  ifdef HAVE_PTRACE64
 145   int ret = ptrace64 (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 146 #  else
 147   int ret = ptracex (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 148 #  endif
 149 #else
 150   int ret = 0;
 151 #endif
 152 #if 0
 153   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 154           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 155 #endif
 156   return ret;
 157 }
 158
 159 /* Fetch register REGNO from the inferior.  */
 160
 161 static void
 162 fetch_register (struct regcache *regcache, int regno)
 163 {
 164   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 165   int addr[MAX_REGISTER_SIZE];
 166   int nr, isfloat;
 167
 168   /* Retrieved values may be -1, so infer errors from errno.  */
 169   errno = 0;
 170
 171   nr = regmap (gdbarch, regno, &isfloat);
 172
 173   /* Floating-point registers.  */
 174   if (isfloat)
 175     rs6000_ptrace32 (PT_READ_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 176
 177   /* Bogus register number.  */
 178   else if (nr < 0)
 179     {
 180       if (regno >= gdbarch_num_regs (gdbarch))
 181         fprintf_unfiltered (gdb_stderr,
 182                             "gdb error: register no %d not implemented.\n",
 183                             regno);
 184       return;
 185     }
 186
 187   /* Fixed-point registers.  */
 188   else
 189     {
 190       if (!ARCH64 ())
 191         *addr = rs6000_ptrace32 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 192                                  (int *) nr, 0, 0);
 193       else
 194         {
 195           /* PT_READ_GPR requires the buffer parameter to point to long long,
 196              even if the register is really only 32 bits.  */
 197           long long buf;
 198           rs6000_ptrace64 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
 199                            nr, 0, &buf);
 200           if (register_size (gdbarch, regno) == 8)
 201             memcpy (addr, &buf, 8);
 202           else
 203             *addr = buf;
 204         }
 205     }
 206
 207   if (!errno)
 208     regcache_raw_supply (regcache, regno, (char *) addr);
 209   else
 210     {
 211 #if 0
 212       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 213       perror (_("ptrace read"));
 214 #endif
 215       errno = 0;
 216     }
 217 }
 218
 219 /* Store register REGNO back into the inferior.  */
 220
 221 static void
 222 store_register (struct regcache *regcache, int regno)
 223 {
 224   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 225   int addr[MAX_REGISTER_SIZE];
 226   int nr, isfloat;
 227
 228   /* Fetch the register's value from the register cache.  */
 229   regcache_raw_collect (regcache, regno, addr);
 230
 231   /* -1 can be a successful return value, so infer errors from errno.  */
 232   errno = 0;
 233
 234   nr = regmap (gdbarch, regno, &isfloat);
 235
 236   /* Floating-point registers.  */
 237   if (isfloat)
 238     rs6000_ptrace32 (PT_WRITE_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);
 239
 240   /* Bogus register number.  */
 241   else if (nr < 0)
 242     {
 243       if (regno >= gdbarch_num_regs (gdbarch))
 244         fprintf_unfiltered (gdb_stderr,
 245                             "gdb error: register no %d not implemented.\n",
 246                             regno);
 247     }
 248
 249   /* Fixed-point registers.  */
 250   else
 251     {
 252       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 253          the register's value is passed by value, but for 64-bit inferiors,
 254          the address of a buffer containing the value is passed.  */
 255       if (!ARCH64 ())
 256         rs6000_ptrace32 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 257                          (int *) nr, *addr, 0);
 258       else
 259         {
 260           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 261              area, even if the register is really only 32 bits.  */
 262           long long buf;
 263           if (register_size (gdbarch, regno) == 8)
 264             memcpy (&buf, addr, 8);
 265           else
 266             buf = *addr;
 267           rs6000_ptrace64 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
 268                            nr, 0, &buf);
 269         }
 270     }
 271
 272   if (errno)
 273     {
 274       perror (_("ptrace write"));
 275       errno = 0;
 276     }
 277 }
 278
 279 /* Read from the inferior all registers if REGNO == -1 and just register
 280    REGNO otherwise.  */
 281
 282 static void
 283 rs6000_fetch_inferior_registers (struct target_ops *ops,
 284                                  struct regcache *regcache, int regno)
 285 {
 286   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 287   if (regno != -1)
 288     fetch_register (regcache, regno);
 289
 290   else
 291     {
 292       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 293
 294       /* Read 32 general purpose registers.  */
 295       for (regno = tdep->ppc_gp0_regnum;
 296            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 297            regno++)
 298         {
 299           fetch_register (regcache, regno);
 300         }
 301
 302       /* Read general purpose floating point registers.  */
 303       if (tdep->ppc_fp0_regnum >= 0)
 304         for (regno = 0; regno < ppc_num_fprs; regno++)
 305           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 306
 307       /* Read special registers.  */
 308       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 309       fetch_register (regcache, tdep->ppc_ps_regnum);
 310       fetch_register (regcache, tdep->ppc_cr_regnum);
 311       fetch_register (regcache, tdep->ppc_lr_regnum);
 312       fetch_register (regcache, tdep->ppc_ctr_regnum);
 313       fetch_register (regcache, tdep->ppc_xer_regnum);
 314       if (tdep->ppc_fpscr_regnum >= 0)
 315         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 316       if (tdep->ppc_mq_regnum >= 0)
 317         fetch_register (regcache, tdep->ppc_mq_regnum);
 318     }
 319 }
 320
 321 /* Store our register values back into the inferior.
 322    If REGNO is -1, do this for all registers.
 323    Otherwise, REGNO specifies which register (so we can save time).  */
 324
 325 static void
 326 rs6000_store_inferior_registers (struct target_ops *ops,
 327                                  struct regcache *regcache, int regno)
 328 {
 329   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 330   if (regno != -1)
 331     store_register (regcache, regno);
 332
 333   else
 334     {
 335       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 336
 337       /* Write general purpose registers first.  */
 338       for (regno = tdep->ppc_gp0_regnum;
 339            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 340            regno++)
 341         {
 342           store_register (regcache, regno);
 343         }
 344
 345       /* Write floating point registers.  */
 346       if (tdep->ppc_fp0_regnum >= 0)
 347         for (regno = 0; regno < ppc_num_fprs; regno++)
 348           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 349
 350       /* Write special registers.  */
 351       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 352       store_register (regcache, tdep->ppc_ps_regnum);
 353       store_register (regcache, tdep->ppc_cr_regnum);
 354       store_register (regcache, tdep->ppc_lr_regnum);
 355       store_register (regcache, tdep->ppc_ctr_regnum);
 356       store_register (regcache, tdep->ppc_xer_regnum);
 357       if (tdep->ppc_fpscr_regnum >= 0)
 358         store_register (regcache, tdep->ppc_fpscr_regnum);
 359       if (tdep->ppc_mq_regnum >= 0)
 360         store_register (regcache, tdep->ppc_mq_regnum);
 361     }
 362 }
 363
 364 /* Implement the to_xfer_partial target_ops method.  */
 365
 366 static enum target_xfer_status
 367 rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
 368                      const char *annex, gdb_byte *readbuf,
 369                      const gdb_byte *writebuf,
 370                      ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 371 {
 372   pid_t pid = ptid_get_pid (inferior_ptid);
 373   int arch64 = ARCH64 ();
 374
 375   switch (object)
 376     {
 377     case TARGET_OBJECT_LIBRARIES_AIX:
 378       return rs6000_xfer_shared_libraries (ops, object, annex,
 379                                            readbuf, writebuf,
 380                                            offset, len, xfered_len);
 381     case TARGET_OBJECT_MEMORY:
 382       {
 383         union
 384         {
 385           PTRACE_TYPE_RET word;
 386           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 387         } buffer;
 388         ULONGEST rounded_offset;
 389         LONGEST partial_len;
 390
 391         /* Round the start offset down to the next long word
 392            boundary.  */
 393         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 394
 395         /* Since ptrace will transfer a single word starting at that
 396            rounded_offset the partial_len needs to be adjusted down to
 397            that (remember this function only does a single transfer).
 398            Should the required length be even less, adjust it down
 399            again.  */
 400         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 401         if (partial_len > len)
 402           partial_len = len;
 403
 404         if (writebuf)
 405           {
 406             /* If OFFSET:PARTIAL_LEN is smaller than
 407                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 408                be needed.  Read in the entire word.  */
 409             if (rounded_offset < offset
 410                 || (offset + partial_len
 411                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 412               {
 413                 /* Need part of initial word -- fetch it.  */
 414                 if (arch64)
 415                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 416                                                  rounded_offset, 0, NULL);
 417                 else
 418                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 419                                                  (int *) (uintptr_t)
 420                                                  rounded_offset,
 421                                                  0, NULL);
 422               }
 423
 424             /* Copy data to be written over corresponding part of
 425                buffer.  */
 426             memcpy (buffer.byte + (offset - rounded_offset),
 427                     writebuf, partial_len);
 428
 429             errno = 0;
 430             if (arch64)
 431               rs6000_ptrace64 (PT_WRITE_D, pid,
 432                                rounded_offset, buffer.word, NULL);
 433             else
 434               rs6000_ptrace32 (PT_WRITE_D, pid,
 435                                (int *) (uintptr_t) rounded_offset,
 436                                buffer.word, NULL);
 437             if (errno)
 438               return TARGET_XFER_EOF;
 439           }
 440
 441         if (readbuf)
 442           {
 443             errno = 0;
 444             if (arch64)
 445               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 446                                              rounded_offset, 0, NULL);
 447             else
 448               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 449                                              (int *)(uintptr_t)rounded_offset,
 450                                              0, NULL);
 451             if (errno)
 452               return TARGET_XFER_EOF;
 453
 454             /* Copy appropriate bytes out of the buffer.  */
 455             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 456                     partial_len);
 457           }
 458
 459         *xfered_len = (ULONGEST) partial_len;
 460         return TARGET_XFER_OK;
 461       }
 462
 463     default:
 464       return TARGET_XFER_E_IO;
 465     }
 466 }
 467
 468 /* Wait for the child specified by PTID to do something.  Return the
 469    process ID of the child, or MINUS_ONE_PTID in case of error; store
 470    the status in *OURSTATUS.  */
 471
 472 static ptid_t
 473 rs6000_wait (struct target_ops *ops,
 474              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
 475 {
 476   pid_t pid;
 477   int status, save_errno;
 478
 479   do
 480     {
 481       set_sigint_trap ();
 482
 483       do
 484         {
 485           pid = waitpid (ptid_get_pid (ptid), &status, 0);
 486           save_errno = errno;
 487         }
 488       while (pid == -1 && errno == EINTR);
 489
 490       clear_sigint_trap ();
 491
 492       if (pid == -1)
 493         {
 494           fprintf_unfiltered (gdb_stderr,
 495                               _("Child process unexpectedly missing: %s.\n"),
 496                               safe_strerror (save_errno));
 497
 498           /* Claim it exited with unknown signal.  */
 499           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 500           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 501           return inferior_ptid;
 502         }
 503
 504       /* Ignore terminated detached child processes.  */
 505       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
 506         pid = -1;
 507     }
 508   while (pid == -1);
 509
 510   /* AIX has a couple of strange returns from wait().  */
 511
 512   /* stop after load" status.  */
 513   if (status == 0x57c)
 514     ourstatus->kind = TARGET_WAITKIND_LOADED;
 515   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 516   else if (status == 0x7f)
 517     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 518   /* A normal waitstatus.  Let the usual macros deal with it.  */
 519   else
 520     store_waitstatus (ourstatus, status);
 521
 522   return pid_to_ptid (pid);
 523 }
 524 \f
 525
 526 /* Set the current architecture from the host running GDB.  Called when
 527    starting a child process.  */
 528
 529 static void (*super_create_inferior) (struct target_ops *,char *exec_file,
 530                                       char *allargs, char **env, int from_tty);
 531 static void
 532 rs6000_create_inferior (struct target_ops * ops, char *exec_file,
 533                         char *allargs, char **env, int from_tty)
 534 {
 535   enum bfd_architecture arch;
 536   unsigned long mach;
 537   bfd abfd;
 538   struct gdbarch_info info;
 539
 540   super_create_inferior (ops, exec_file, allargs, env, from_tty);
 541
 542   if (__power_rs ())
 543     {
 544       arch = bfd_arch_rs6000;
 545       mach = bfd_mach_rs6k;
 546     }
 547   else
 548     {
 549       arch = bfd_arch_powerpc;
 550       mach = bfd_mach_ppc;
 551     }
 552
 553   /* FIXME: schauer/2002-02-25:
 554      We don't know if we are executing a 32 or 64 bit executable,
 555      and have no way to pass the proper word size to rs6000_gdbarch_init.
 556      So we have to avoid switching to a new architecture, if the architecture
 557      matches already.
 558      Blindly calling rs6000_gdbarch_init used to work in older versions of
 559      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 560      determine the wordsize.  */
 561   if (exec_bfd)
 562     {
 563       const struct bfd_arch_info *exec_bfd_arch_info;
 564
 565       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
 566       if (arch == exec_bfd_arch_info->arch)
 567         return;
 568     }
 569
 570   bfd_default_set_arch_mach (&abfd, arch, mach);
 571
 572   gdbarch_info_init (&info);
 573   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 574   info.abfd = exec_bfd;
 575
 576   if (!gdbarch_update_p (info))
 577     internal_error (__FILE__, __LINE__,
 578                     _("rs6000_create_inferior: failed "
 579                       "to select architecture"));
 580 }
 581 \f
 582
 583 /* Shared Object support.  */
 584
 585 /* Return the LdInfo data for the given process.  Raises an error
 586    if the data could not be obtained.
 587
 588    The returned value must be deallocated after use.  */
 589
 590 static gdb_byte *
 591 rs6000_ptrace_ldinfo (ptid_t ptid)
 592 {
 593   const int pid = ptid_get_pid (ptid);
 594   int ldi_size = 1024;
 595   void *ldi = xmalloc (ldi_size);
 596   int rc = -1;
 597
 598   while (1)
 599     {
 600       if (ARCH64 ())
 601         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
 602                               NULL);
 603       else
 604         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);
 605
 606       if (rc != -1)
 607         break; /* Success, we got the entire ld_info data.  */
 608
 609       if (errno != ENOMEM)
 610         perror_with_name (_("ptrace ldinfo"));
 611
 612       /* ldi is not big enough.  Double it and try again.  */
 613       ldi_size *= 2;
 614       ldi = xrealloc (ldi, ldi_size);
 615     }
 616
 617   return (gdb_byte *) ldi;
 618 }
 619
 620 /* Implement the to_xfer_partial target_ops method for
 621    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 622
 623 static enum target_xfer_status
 624 rs6000_xfer_shared_libraries
 625   (struct target_ops *ops, enum target_object object,
 626    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 627    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 628 {
 629   gdb_byte *ldi_buf;
 630   ULONGEST result;
 631   struct cleanup *cleanup;
 632
 633   /* This function assumes that it is being run with a live process.
 634      Core files are handled via gdbarch.  */
 635   gdb_assert (target_has_execution);
 636
 637   if (writebuf)
 638     return TARGET_XFER_E_IO;
 639
 640   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 641   gdb_assert (ldi_buf != NULL);
 642   cleanup = make_cleanup (xfree, ldi_buf);
 643   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
 644                                       readbuf, offset, len, 1);
 645   xfree (ldi_buf);
 646
 647   do_cleanups (cleanup);
 648
 649   if (result == 0)
 650     return TARGET_XFER_EOF;
 651   else
 652     {
 653       *xfered_len = result;
 654       return TARGET_XFER_OK;
 655     }
 656 }
 657
 658 void _initialize_rs6000_nat (void);
 659
 660 void
 661 _initialize_rs6000_nat (void)
 662 {
 663   struct target_ops *t;
 664
 665   t = inf_ptrace_target ();
 666   t->to_fetch_registers = rs6000_fetch_inferior_registers;
 667   t->to_store_registers = rs6000_store_inferior_registers;
 668   t->to_xfer_partial = rs6000_xfer_partial;
 669
 670   super_create_inferior = t->to_create_inferior;
 671   t->to_create_inferior = rs6000_create_inferior;
 672
 673   t->to_wait = rs6000_wait;
 674
 675   add_target (t);
 676 }