gdb/rs6000-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2021 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 "observable.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 class rs6000_nat_target final : public inf_ptrace_target
  78 {
  79 public:
  80   void fetch_registers (struct regcache *, int) override;
  81   void store_registers (struct regcache *, int) override;
  82
  83   enum target_xfer_status xfer_partial (enum target_object object,
  84                                         const char *annex,
  85                                         gdb_byte *readbuf,
  86                                         const gdb_byte *writebuf,
  87                                         ULONGEST offset, ULONGEST len,
  88                                         ULONGEST *xfered_len) override;
  89
  90   void create_inferior (const char *, const std::string &,
  91                         char **, int) override;
  92
  93   ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
  94
  95 private:
  96   enum target_xfer_status
  97     xfer_shared_libraries (enum target_object object,
  98                            const char *annex, gdb_byte *readbuf,
  99                            const gdb_byte *writebuf,
 100                            ULONGEST offset, ULONGEST len,
 101                            ULONGEST *xfered_len);
 102 };
 103
 104 static rs6000_nat_target the_rs6000_nat_target;
 105
 106 /* Given REGNO, a gdb register number, return the corresponding
 107    number suitable for use as a ptrace() parameter.  Return -1 if
 108    there's no suitable mapping.  Also, set the int pointed to by
 109    ISFLOAT to indicate whether REGNO is a floating point register.  */
 110
 111 static int
 112 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
 113 {
 114   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 115
 116   *isfloat = 0;
 117   if (tdep->ppc_gp0_regnum <= regno
 118       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
 119     return regno;
 120   else if (tdep->ppc_fp0_regnum >= 0
 121            && tdep->ppc_fp0_regnum <= regno
 122            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 123     {
 124       *isfloat = 1;
 125       return regno - tdep->ppc_fp0_regnum + FPR0;
 126     }
 127   else if (regno == gdbarch_pc_regnum (gdbarch))
 128     return IAR;
 129   else if (regno == tdep->ppc_ps_regnum)
 130     return MSR;
 131   else if (regno == tdep->ppc_cr_regnum)
 132     return CR;
 133   else if (regno == tdep->ppc_lr_regnum)
 134     return LR;
 135   else if (regno == tdep->ppc_ctr_regnum)
 136     return CTR;
 137   else if (regno == tdep->ppc_xer_regnum)
 138     return XER;
 139   else if (tdep->ppc_fpscr_regnum >= 0
 140            && regno == tdep->ppc_fpscr_regnum)
 141     return FPSCR;
 142   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 143     return MQ;
 144   else
 145     return -1;
 146 }
 147
 148 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 149
 150 static int
 151 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 152 {
 153 #ifdef HAVE_PTRACE64
 154   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 155 #else
 156   int ret = ptrace (req, id, (int *)addr, data, buf);
 157 #endif
 158 #if 0
 159   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 160           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 161 #endif
 162   return ret;
 163 }
 164
 165 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 166
 167 static int
 168 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 169 {
 170 #ifdef ARCH3264
 171 #  ifdef HAVE_PTRACE64
 172   int ret = ptrace64 (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 173 #  else
 174   int ret = ptracex (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 175 #  endif
 176 #else
 177   int ret = 0;
 178 #endif
 179 #if 0
 180   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 181           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 182 #endif
 183   return ret;
 184 }
 185
 186 /* Fetch register REGNO from the inferior.  */
 187
 188 static void
 189 fetch_register (struct regcache *regcache, int regno)
 190 {
 191   struct gdbarch *gdbarch = regcache->arch ();
 192   int addr[PPC_MAX_REGISTER_SIZE];
 193   int nr, isfloat;
 194   pid_t pid = regcache->ptid ().pid ();
 195
 196   /* Retrieved values may be -1, so infer errors from errno.  */
 197   errno = 0;
 198
 199   nr = regmap (gdbarch, regno, &isfloat);
 200
 201   /* Floating-point registers.  */
 202   if (isfloat)
 203     rs6000_ptrace32 (PT_READ_FPR, pid, addr, nr, 0);
 204
 205   /* Bogus register number.  */
 206   else if (nr < 0)
 207     {
 208       if (regno >= gdbarch_num_regs (gdbarch))
 209         fprintf_unfiltered (gdb_stderr,
 210                             "gdb error: register no %d not implemented.\n",
 211                             regno);
 212       return;
 213     }
 214
 215   /* Fixed-point registers.  */
 216   else
 217     {
 218       if (!ARCH64 ())
 219         *addr = rs6000_ptrace32 (PT_READ_GPR, pid, (int *) nr, 0, 0);
 220       else
 221         {
 222           /* PT_READ_GPR requires the buffer parameter to point to long long,
 223              even if the register is really only 32 bits.  */
 224           long long buf;
 225           rs6000_ptrace64 (PT_READ_GPR, pid, nr, 0, &buf);
 226           if (register_size (gdbarch, regno) == 8)
 227             memcpy (addr, &buf, 8);
 228           else
 229             *addr = buf;
 230         }
 231     }
 232
 233   if (!errno)
 234     regcache->raw_supply (regno, (char *) addr);
 235   else
 236     {
 237 #if 0
 238       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 239       perror (_("ptrace read"));
 240 #endif
 241       errno = 0;
 242     }
 243 }
 244
 245 /* Store register REGNO back into the inferior.  */
 246
 247 static void
 248 store_register (struct regcache *regcache, int regno)
 249 {
 250   struct gdbarch *gdbarch = regcache->arch ();
 251   int addr[PPC_MAX_REGISTER_SIZE];
 252   int nr, isfloat;
 253   pid_t pid = regcache->ptid ().pid ();
 254
 255   /* Fetch the register's value from the register cache.  */
 256   regcache->raw_collect (regno, addr);
 257
 258   /* -1 can be a successful return value, so infer errors from errno.  */
 259   errno = 0;
 260
 261   nr = regmap (gdbarch, regno, &isfloat);
 262
 263   /* Floating-point registers.  */
 264   if (isfloat)
 265     rs6000_ptrace32 (PT_WRITE_FPR, pid, addr, nr, 0);
 266
 267   /* Bogus register number.  */
 268   else if (nr < 0)
 269     {
 270       if (regno >= gdbarch_num_regs (gdbarch))
 271         fprintf_unfiltered (gdb_stderr,
 272                             "gdb error: register no %d not implemented.\n",
 273                             regno);
 274     }
 275
 276   /* Fixed-point registers.  */
 277   else
 278     {
 279       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 280          the register's value is passed by value, but for 64-bit inferiors,
 281          the address of a buffer containing the value is passed.  */
 282       if (!ARCH64 ())
 283         rs6000_ptrace32 (PT_WRITE_GPR, pid, (int *) nr, *addr, 0);
 284       else
 285         {
 286           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 287              area, even if the register is really only 32 bits.  */
 288           long long buf;
 289           if (register_size (gdbarch, regno) == 8)
 290             memcpy (&buf, addr, 8);
 291           else
 292             buf = *addr;
 293           rs6000_ptrace64 (PT_WRITE_GPR, pid, nr, 0, &buf);
 294         }
 295     }
 296
 297   if (errno)
 298     {
 299       perror (_("ptrace write"));
 300       errno = 0;
 301     }
 302 }
 303
 304 /* Read from the inferior all registers if REGNO == -1 and just register
 305    REGNO otherwise.  */
 306
 307 void
 308 rs6000_nat_target::fetch_registers (struct regcache *regcache, int regno)
 309 {
 310   struct gdbarch *gdbarch = regcache->arch ();
 311   if (regno != -1)
 312     fetch_register (regcache, regno);
 313
 314   else
 315     {
 316       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 317
 318       /* Read 32 general purpose registers.  */
 319       for (regno = tdep->ppc_gp0_regnum;
 320            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 321            regno++)
 322         {
 323           fetch_register (regcache, regno);
 324         }
 325
 326       /* Read general purpose floating point registers.  */
 327       if (tdep->ppc_fp0_regnum >= 0)
 328         for (regno = 0; regno < ppc_num_fprs; regno++)
 329           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 330
 331       /* Read special registers.  */
 332       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 333       fetch_register (regcache, tdep->ppc_ps_regnum);
 334       fetch_register (regcache, tdep->ppc_cr_regnum);
 335       fetch_register (regcache, tdep->ppc_lr_regnum);
 336       fetch_register (regcache, tdep->ppc_ctr_regnum);
 337       fetch_register (regcache, tdep->ppc_xer_regnum);
 338       if (tdep->ppc_fpscr_regnum >= 0)
 339         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 340       if (tdep->ppc_mq_regnum >= 0)
 341         fetch_register (regcache, tdep->ppc_mq_regnum);
 342     }
 343 }
 344
 345 /* Store our register values back into the inferior.
 346    If REGNO is -1, do this for all registers.
 347    Otherwise, REGNO specifies which register (so we can save time).  */
 348
 349 void
 350 rs6000_nat_target::store_registers (struct regcache *regcache, int regno)
 351 {
 352   struct gdbarch *gdbarch = regcache->arch ();
 353   if (regno != -1)
 354     store_register (regcache, regno);
 355
 356   else
 357     {
 358       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
 359
 360       /* Write general purpose registers first.  */
 361       for (regno = tdep->ppc_gp0_regnum;
 362            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 363            regno++)
 364         {
 365           store_register (regcache, regno);
 366         }
 367
 368       /* Write floating point registers.  */
 369       if (tdep->ppc_fp0_regnum >= 0)
 370         for (regno = 0; regno < ppc_num_fprs; regno++)
 371           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 372
 373       /* Write special registers.  */
 374       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 375       store_register (regcache, tdep->ppc_ps_regnum);
 376       store_register (regcache, tdep->ppc_cr_regnum);
 377       store_register (regcache, tdep->ppc_lr_regnum);
 378       store_register (regcache, tdep->ppc_ctr_regnum);
 379       store_register (regcache, tdep->ppc_xer_regnum);
 380       if (tdep->ppc_fpscr_regnum >= 0)
 381         store_register (regcache, tdep->ppc_fpscr_regnum);
 382       if (tdep->ppc_mq_regnum >= 0)
 383         store_register (regcache, tdep->ppc_mq_regnum);
 384     }
 385 }
 386
 387 /* Implement the to_xfer_partial target_ops method.  */
 388
 389 enum target_xfer_status
 390 rs6000_nat_target::xfer_partial (enum target_object object,
 391                                  const char *annex, gdb_byte *readbuf,
 392                                  const gdb_byte *writebuf,
 393                                  ULONGEST offset, ULONGEST len,
 394                                  ULONGEST *xfered_len)
 395 {
 396   pid_t pid = inferior_ptid.pid ();
 397   int arch64 = ARCH64 ();
 398
 399   switch (object)
 400     {
 401     case TARGET_OBJECT_LIBRARIES_AIX:
 402       return xfer_shared_libraries (object, annex,
 403                                     readbuf, writebuf,
 404                                     offset, len, xfered_len);
 405     case TARGET_OBJECT_MEMORY:
 406       {
 407         union
 408         {
 409           PTRACE_TYPE_RET word;
 410           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 411         } buffer;
 412         ULONGEST rounded_offset;
 413         LONGEST partial_len;
 414
 415         /* Round the start offset down to the next long word
 416            boundary.  */
 417         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 418
 419         /* Since ptrace will transfer a single word starting at that
 420            rounded_offset the partial_len needs to be adjusted down to
 421            that (remember this function only does a single transfer).
 422            Should the required length be even less, adjust it down
 423            again.  */
 424         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 425         if (partial_len > len)
 426           partial_len = len;
 427
 428         if (writebuf)
 429           {
 430             /* If OFFSET:PARTIAL_LEN is smaller than
 431                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 432                be needed.  Read in the entire word.  */
 433             if (rounded_offset < offset
 434                 || (offset + partial_len
 435                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 436               {
 437                 /* Need part of initial word -- fetch it.  */
 438                 if (arch64)
 439                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 440                                                  rounded_offset, 0, NULL);
 441                 else
 442                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 443                                                  (int *) (uintptr_t)
 444                                                  rounded_offset,
 445                                                  0, NULL);
 446               }
 447
 448             /* Copy data to be written over corresponding part of
 449                buffer.  */
 450             memcpy (buffer.byte + (offset - rounded_offset),
 451                     writebuf, partial_len);
 452
 453             errno = 0;
 454             if (arch64)
 455               rs6000_ptrace64 (PT_WRITE_D, pid,
 456                                rounded_offset, buffer.word, NULL);
 457             else
 458               rs6000_ptrace32 (PT_WRITE_D, pid,
 459                                (int *) (uintptr_t) rounded_offset,
 460                                buffer.word, NULL);
 461             if (errno)
 462               return TARGET_XFER_EOF;
 463           }
 464
 465         if (readbuf)
 466           {
 467             errno = 0;
 468             if (arch64)
 469               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 470                                              rounded_offset, 0, NULL);
 471             else
 472               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 473                                              (int *)(uintptr_t)rounded_offset,
 474                                              0, NULL);
 475             if (errno)
 476               return TARGET_XFER_EOF;
 477
 478             /* Copy appropriate bytes out of the buffer.  */
 479             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 480                     partial_len);
 481           }
 482
 483         *xfered_len = (ULONGEST) partial_len;
 484         return TARGET_XFER_OK;
 485       }
 486
 487     default:
 488       return TARGET_XFER_E_IO;
 489     }
 490 }
 491
 492 /* Wait for the child specified by PTID to do something.  Return the
 493    process ID of the child, or MINUS_ONE_PTID in case of error; store
 494    the status in *OURSTATUS.  */
 495
 496 ptid_t
 497 rs6000_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
 498                          target_wait_flags options)
 499 {
 500   pid_t pid;
 501   int status, save_errno;
 502
 503   do
 504     {
 505       set_sigint_trap ();
 506
 507       do
 508         {
 509           pid = waitpid (ptid.pid (), &status, 0);
 510           save_errno = errno;
 511         }
 512       while (pid == -1 && errno == EINTR);
 513
 514       clear_sigint_trap ();
 515
 516       if (pid == -1)
 517         {
 518           fprintf_unfiltered (gdb_stderr,
 519                               _("Child process unexpectedly missing: %s.\n"),
 520                               safe_strerror (save_errno));
 521
 522           /* Claim it exited with unknown signal.  */
 523           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
 524           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
 525           return inferior_ptid;
 526         }
 527
 528       /* Ignore terminated detached child processes.  */
 529       if (!WIFSTOPPED (status) && pid != inferior_ptid.pid ())
 530         pid = -1;
 531     }
 532   while (pid == -1);
 533
 534   /* AIX has a couple of strange returns from wait().  */
 535
 536   /* stop after load" status.  */
 537   if (status == 0x57c)
 538     ourstatus->kind = TARGET_WAITKIND_LOADED;
 539   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 540   else if (status == 0x7f)
 541     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
 542   /* A normal waitstatus.  Let the usual macros deal with it.  */
 543   else
 544     store_waitstatus (ourstatus, status);
 545
 546   return ptid_t (pid);
 547 }
 548 \f
 549
 550 /* Set the current architecture from the host running GDB.  Called when
 551    starting a child process.  */
 552
 553 void
 554 rs6000_nat_target::create_inferior (const char *exec_file,
 555                                     const std::string &allargs,
 556                                     char **env, int from_tty)
 557 {
 558   enum bfd_architecture arch;
 559   unsigned long mach;
 560   bfd abfd;
 561
 562   inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
 563
 564   if (__power_rs ())
 565     {
 566       arch = bfd_arch_rs6000;
 567       mach = bfd_mach_rs6k;
 568     }
 569   else
 570     {
 571       arch = bfd_arch_powerpc;
 572       mach = bfd_mach_ppc;
 573     }
 574
 575   /* FIXME: schauer/2002-02-25:
 576      We don't know if we are executing a 32 or 64 bit executable,
 577      and have no way to pass the proper word size to rs6000_gdbarch_init.
 578      So we have to avoid switching to a new architecture, if the architecture
 579      matches already.
 580      Blindly calling rs6000_gdbarch_init used to work in older versions of
 581      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 582      determine the wordsize.  */
 583   if (current_program_space->exec_bfd ())
 584     {
 585       const struct bfd_arch_info *exec_bfd_arch_info;
 586
 587       exec_bfd_arch_info
 588         = bfd_get_arch_info (current_program_space->exec_bfd ());
 589       if (arch == exec_bfd_arch_info->arch)
 590         return;
 591     }
 592
 593   bfd_default_set_arch_mach (&abfd, arch, mach);
 594
 595   gdbarch_info info;
 596   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 597   info.abfd = current_program_space->exec_bfd ();
 598
 599   if (!gdbarch_update_p (info))
 600     internal_error (__FILE__, __LINE__,
 601                     _("rs6000_create_inferior: failed "
 602                       "to select architecture"));
 603 }
 604 \f
 605
 606 /* Shared Object support.  */
 607
 608 /* Return the LdInfo data for the given process.  Raises an error
 609    if the data could not be obtained.  */
 610
 611 static gdb::byte_vector
 612 rs6000_ptrace_ldinfo (ptid_t ptid)
 613 {
 614   const int pid = ptid.pid ();
 615   gdb::byte_vector ldi (1024);
 616   int rc = -1;
 617
 618   while (1)
 619     {
 620       if (ARCH64 ())
 621         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi.data (),
 622                               ldi.size (), NULL);
 623       else
 624         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi.data (),
 625                               ldi.size (), NULL);
 626
 627       if (rc != -1)
 628         break; /* Success, we got the entire ld_info data.  */
 629
 630       if (errno != ENOMEM)
 631         perror_with_name (_("ptrace ldinfo"));
 632
 633       /* ldi is not big enough.  Double it and try again.  */
 634       ldi.resize (ldi.size () * 2);
 635     }
 636
 637   return ldi;
 638 }
 639
 640 /* Implement the to_xfer_partial target_ops method for
 641    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 642
 643 enum target_xfer_status
 644 rs6000_nat_target::xfer_shared_libraries
 645   (enum target_object object,
 646    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 647    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 648 {
 649   ULONGEST result;
 650
 651   /* This function assumes that it is being run with a live process.
 652      Core files are handled via gdbarch.  */
 653   gdb_assert (target_has_execution ());
 654
 655   if (writebuf)
 656     return TARGET_XFER_E_IO;
 657
 658   gdb::byte_vector ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 659   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf.data (),
 660                                       readbuf, offset, len, 1);
 661
 662   if (result == 0)
 663     return TARGET_XFER_EOF;
 664   else
 665     {
 666       *xfered_len = result;
 667       return TARGET_XFER_OK;
 668     }
 669 }
 670
 671 void _initialize_rs6000_nat ();
 672 void
 673 _initialize_rs6000_nat ()
 674 {
 675   add_inf_child_target (&the_rs6000_nat_target);
 676 }