gdb/rs6000-aix-nat.c

   1 /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2022 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-aix-tdep.h"
  34 #include "exec.h"
  35 #include "observable.h"
  36 #include "xcoffread.h"
  37
  38 #include <sys/ptrace.h>
  39 #include <sys/reg.h>
  40
  41 #include <sys/dir.h>
  42 #include <sys/user.h>
  43 #include <signal.h>
  44 #include <sys/ioctl.h>
  45 #include <fcntl.h>
  46
  47 #include <a.out.h>
  48 #include <sys/file.h>
  49 #include <sys/stat.h>
  50 #include "gdb_bfd.h"
  51 #include <sys/core.h>
  52 #define __LDINFO_PTRACE32__     /* for __ld_info32 */
  53 #define __LDINFO_PTRACE64__     /* for __ld_info64 */
  54 #include <sys/ldr.h>
  55 #include <sys/systemcfg.h>
  56
  57 /* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
  58    debugging 32-bit and 64-bit processes.  Define a typedef and macros for
  59    accessing fields in the appropriate structures.  */
  60
  61 /* In 32-bit compilation mode (which is the only mode from which ptrace()
  62    works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */
  63
  64 #if defined (__ld_info32) || defined (__ld_info64)
  65 # define ARCH3264
  66 #endif
  67
  68 /* Return whether the current architecture is 64-bit.  */
  69
  70 #ifndef ARCH3264
  71 # define ARCH64() 0
  72 #else
  73 # define ARCH64() (register_size (target_gdbarch (), 0) == 8)
  74 #endif
  75
  76 class rs6000_nat_target final : public inf_ptrace_target
  77 {
  78 public:
  79   void fetch_registers (struct regcache *, int) override;
  80   void store_registers (struct regcache *, int) override;
  81
  82   enum target_xfer_status xfer_partial (enum target_object object,
  83                                         const char *annex,
  84                                         gdb_byte *readbuf,
  85                                         const gdb_byte *writebuf,
  86                                         ULONGEST offset, ULONGEST len,
  87                                         ULONGEST *xfered_len) override;
  88
  89   void create_inferior (const char *, const std::string &,
  90                         char **, int) override;
  91
  92   ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
  93
  94 protected:
  95
  96   void post_startup_inferior (ptid_t ptid) override
  97   { /* Nothing.  */ }
  98
  99 private:
 100   enum target_xfer_status
 101     xfer_shared_libraries (enum target_object object,
 102                            const char *annex, gdb_byte *readbuf,
 103                            const gdb_byte *writebuf,
 104                            ULONGEST offset, ULONGEST len,
 105                            ULONGEST *xfered_len);
 106 };
 107
 108 static rs6000_nat_target the_rs6000_nat_target;
 109
 110 /* Given REGNO, a gdb register number, return the corresponding
 111    number suitable for use as a ptrace() parameter.  Return -1 if
 112    there's no suitable mapping.  Also, set the int pointed to by
 113    ISFLOAT to indicate whether REGNO is a floating point register.  */
 114
 115 static int
 116 regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
 117 {
 118   ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 119
 120   *isfloat = 0;
 121   if (tdep->ppc_gp0_regnum <= regno
 122       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
 123     return regno;
 124   else if (tdep->ppc_fp0_regnum >= 0
 125            && tdep->ppc_fp0_regnum <= regno
 126            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
 127     {
 128       *isfloat = 1;
 129       return regno - tdep->ppc_fp0_regnum + FPR0;
 130     }
 131   else if (regno == gdbarch_pc_regnum (gdbarch))
 132     return IAR;
 133   else if (regno == tdep->ppc_ps_regnum)
 134     return MSR;
 135   else if (regno == tdep->ppc_cr_regnum)
 136     return CR;
 137   else if (regno == tdep->ppc_lr_regnum)
 138     return LR;
 139   else if (regno == tdep->ppc_ctr_regnum)
 140     return CTR;
 141   else if (regno == tdep->ppc_xer_regnum)
 142     return XER;
 143   else if (tdep->ppc_fpscr_regnum >= 0
 144            && regno == tdep->ppc_fpscr_regnum)
 145     return FPSCR;
 146   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
 147     return MQ;
 148   else
 149     return -1;
 150 }
 151
 152 /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */
 153
 154 static int
 155 rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
 156 {
 157 #ifdef HAVE_PTRACE64
 158   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
 159 #else
 160   int ret = ptrace (req, id, (int *)addr, data, buf);
 161 #endif
 162 #if 0
 163   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
 164           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
 165 #endif
 166   return ret;
 167 }
 168
 169 /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */
 170
 171 static int
 172 rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
 173 {
 174 #ifdef ARCH3264
 175 #  ifdef HAVE_PTRACE64
 176   int ret = ptrace64 (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 177 #  else
 178   int ret = ptracex (req, id, addr, data, (PTRACE_TYPE_ARG5) buf);
 179 #  endif
 180 #else
 181   int ret = 0;
 182 #endif
 183 #if 0
 184   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
 185           req, id, hex_string (addr), data, (unsigned int)buf, ret);
 186 #endif
 187   return ret;
 188 }
 189
 190 /* Fetch register REGNO from the inferior.  */
 191
 192 static void
 193 fetch_register (struct regcache *regcache, int regno)
 194 {
 195   struct gdbarch *gdbarch = regcache->arch ();
 196   int addr[PPC_MAX_REGISTER_SIZE];
 197   int nr, isfloat;
 198   pid_t pid = regcache->ptid ().pid ();
 199
 200   /* Retrieved values may be -1, so infer errors from errno.  */
 201   errno = 0;
 202
 203   nr = regmap (gdbarch, regno, &isfloat);
 204
 205   /* Floating-point registers.  */
 206   if (isfloat)
 207     rs6000_ptrace32 (PT_READ_FPR, pid, addr, nr, 0);
 208
 209   /* Bogus register number.  */
 210   else if (nr < 0)
 211     {
 212       if (regno >= gdbarch_num_regs (gdbarch))
 213         gdb_printf (gdb_stderr,
 214                     "gdb error: register no %d not implemented.\n",
 215                     regno);
 216       return;
 217     }
 218
 219   /* Fixed-point registers.  */
 220   else
 221     {
 222       if (!ARCH64 ())
 223         *addr = rs6000_ptrace32 (PT_READ_GPR, pid, (int *) nr, 0, 0);
 224       else
 225         {
 226           /* PT_READ_GPR requires the buffer parameter to point to long long,
 227              even if the register is really only 32 bits.  */
 228           long long buf;
 229           rs6000_ptrace64 (PT_READ_GPR, pid, nr, 0, &buf);
 230           if (register_size (gdbarch, regno) == 8)
 231             memcpy (addr, &buf, 8);
 232           else
 233             *addr = buf;
 234         }
 235     }
 236
 237   if (!errno)
 238     regcache->raw_supply (regno, (char *) addr);
 239   else
 240     {
 241 #if 0
 242       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
 243       perror (_("ptrace read"));
 244 #endif
 245       errno = 0;
 246     }
 247 }
 248
 249 /* Store register REGNO back into the inferior.  */
 250
 251 static void
 252 store_register (struct regcache *regcache, int regno)
 253 {
 254   struct gdbarch *gdbarch = regcache->arch ();
 255   int addr[PPC_MAX_REGISTER_SIZE];
 256   int nr, isfloat;
 257   pid_t pid = regcache->ptid ().pid ();
 258
 259   /* Fetch the register's value from the register cache.  */
 260   regcache->raw_collect (regno, addr);
 261
 262   /* -1 can be a successful return value, so infer errors from errno.  */
 263   errno = 0;
 264
 265   nr = regmap (gdbarch, regno, &isfloat);
 266
 267   /* Floating-point registers.  */
 268   if (isfloat)
 269     rs6000_ptrace32 (PT_WRITE_FPR, pid, addr, nr, 0);
 270
 271   /* Bogus register number.  */
 272   else if (nr < 0)
 273     {
 274       if (regno >= gdbarch_num_regs (gdbarch))
 275         gdb_printf (gdb_stderr,
 276                     "gdb error: register no %d not implemented.\n",
 277                     regno);
 278     }
 279
 280   /* Fixed-point registers.  */
 281   else
 282     {
 283       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
 284          the register's value is passed by value, but for 64-bit inferiors,
 285          the address of a buffer containing the value is passed.  */
 286       if (!ARCH64 ())
 287         rs6000_ptrace32 (PT_WRITE_GPR, pid, (int *) nr, *addr, 0);
 288       else
 289         {
 290           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
 291              area, even if the register is really only 32 bits.  */
 292           long long buf;
 293           if (register_size (gdbarch, regno) == 8)
 294             memcpy (&buf, addr, 8);
 295           else
 296             buf = *addr;
 297           rs6000_ptrace64 (PT_WRITE_GPR, pid, nr, 0, &buf);
 298         }
 299     }
 300
 301   if (errno)
 302     {
 303       perror (_("ptrace write"));
 304       errno = 0;
 305     }
 306 }
 307
 308 /* Read from the inferior all registers if REGNO == -1 and just register
 309    REGNO otherwise.  */
 310
 311 void
 312 rs6000_nat_target::fetch_registers (struct regcache *regcache, int regno)
 313 {
 314   struct gdbarch *gdbarch = regcache->arch ();
 315   if (regno != -1)
 316     fetch_register (regcache, regno);
 317
 318   else
 319     {
 320       ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 321
 322       /* Read 32 general purpose registers.  */
 323       for (regno = tdep->ppc_gp0_regnum;
 324            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 325            regno++)
 326         {
 327           fetch_register (regcache, regno);
 328         }
 329
 330       /* Read general purpose floating point registers.  */
 331       if (tdep->ppc_fp0_regnum >= 0)
 332         for (regno = 0; regno < ppc_num_fprs; regno++)
 333           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);
 334
 335       /* Read special registers.  */
 336       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
 337       fetch_register (regcache, tdep->ppc_ps_regnum);
 338       fetch_register (regcache, tdep->ppc_cr_regnum);
 339       fetch_register (regcache, tdep->ppc_lr_regnum);
 340       fetch_register (regcache, tdep->ppc_ctr_regnum);
 341       fetch_register (regcache, tdep->ppc_xer_regnum);
 342       if (tdep->ppc_fpscr_regnum >= 0)
 343         fetch_register (regcache, tdep->ppc_fpscr_regnum);
 344       if (tdep->ppc_mq_regnum >= 0)
 345         fetch_register (regcache, tdep->ppc_mq_regnum);
 346     }
 347 }
 348
 349 /* Store our register values back into the inferior.
 350    If REGNO is -1, do this for all registers.
 351    Otherwise, REGNO specifies which register (so we can save time).  */
 352
 353 void
 354 rs6000_nat_target::store_registers (struct regcache *regcache, int regno)
 355 {
 356   struct gdbarch *gdbarch = regcache->arch ();
 357   if (regno != -1)
 358     store_register (regcache, regno);
 359
 360   else
 361     {
 362       ppc_gdbarch_tdep *tdep = (ppc_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 363
 364       /* Write general purpose registers first.  */
 365       for (regno = tdep->ppc_gp0_regnum;
 366            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
 367            regno++)
 368         {
 369           store_register (regcache, regno);
 370         }
 371
 372       /* Write floating point registers.  */
 373       if (tdep->ppc_fp0_regnum >= 0)
 374         for (regno = 0; regno < ppc_num_fprs; regno++)
 375           store_register (regcache, tdep->ppc_fp0_regnum + regno);
 376
 377       /* Write special registers.  */
 378       store_register (regcache, gdbarch_pc_regnum (gdbarch));
 379       store_register (regcache, tdep->ppc_ps_regnum);
 380       store_register (regcache, tdep->ppc_cr_regnum);
 381       store_register (regcache, tdep->ppc_lr_regnum);
 382       store_register (regcache, tdep->ppc_ctr_regnum);
 383       store_register (regcache, tdep->ppc_xer_regnum);
 384       if (tdep->ppc_fpscr_regnum >= 0)
 385         store_register (regcache, tdep->ppc_fpscr_regnum);
 386       if (tdep->ppc_mq_regnum >= 0)
 387         store_register (regcache, tdep->ppc_mq_regnum);
 388     }
 389 }
 390
 391 /* Implement the to_xfer_partial target_ops method.  */
 392
 393 enum target_xfer_status
 394 rs6000_nat_target::xfer_partial (enum target_object object,
 395                                  const char *annex, gdb_byte *readbuf,
 396                                  const gdb_byte *writebuf,
 397                                  ULONGEST offset, ULONGEST len,
 398                                  ULONGEST *xfered_len)
 399 {
 400   pid_t pid = inferior_ptid.pid ();
 401   int arch64 = ARCH64 ();
 402
 403   switch (object)
 404     {
 405     case TARGET_OBJECT_LIBRARIES_AIX:
 406       return xfer_shared_libraries (object, annex,
 407                                     readbuf, writebuf,
 408                                     offset, len, xfered_len);
 409     case TARGET_OBJECT_MEMORY:
 410       {
 411         union
 412         {
 413           PTRACE_TYPE_RET word;
 414           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
 415         } buffer;
 416         ULONGEST rounded_offset;
 417         LONGEST partial_len;
 418
 419         /* Round the start offset down to the next long word
 420            boundary.  */
 421         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);
 422
 423         /* Since ptrace will transfer a single word starting at that
 424            rounded_offset the partial_len needs to be adjusted down to
 425            that (remember this function only does a single transfer).
 426            Should the required length be even less, adjust it down
 427            again.  */
 428         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
 429         if (partial_len > len)
 430           partial_len = len;
 431
 432         if (writebuf)
 433           {
 434             /* If OFFSET:PARTIAL_LEN is smaller than
 435                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
 436                be needed.  Read in the entire word.  */
 437             if (rounded_offset < offset
 438                 || (offset + partial_len
 439                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
 440               {
 441                 /* Need part of initial word -- fetch it.  */
 442                 if (arch64)
 443                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 444                                                  rounded_offset, 0, NULL);
 445                 else
 446                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 447                                                  (int *) (uintptr_t)
 448                                                  rounded_offset,
 449                                                  0, NULL);
 450               }
 451
 452             /* Copy data to be written over corresponding part of
 453                buffer.  */
 454             memcpy (buffer.byte + (offset - rounded_offset),
 455                     writebuf, partial_len);
 456
 457             errno = 0;
 458             if (arch64)
 459               rs6000_ptrace64 (PT_WRITE_D, pid,
 460                                rounded_offset, buffer.word, NULL);
 461             else
 462               rs6000_ptrace32 (PT_WRITE_D, pid,
 463                                (int *) (uintptr_t) rounded_offset,
 464                                buffer.word, NULL);
 465             if (errno)
 466               return TARGET_XFER_EOF;
 467           }
 468
 469         if (readbuf)
 470           {
 471             errno = 0;
 472             if (arch64)
 473               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
 474                                              rounded_offset, 0, NULL);
 475             else
 476               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
 477                                              (int *)(uintptr_t)rounded_offset,
 478                                              0, NULL);
 479             if (errno)
 480               return TARGET_XFER_EOF;
 481
 482             /* Copy appropriate bytes out of the buffer.  */
 483             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
 484                     partial_len);
 485           }
 486
 487         *xfered_len = (ULONGEST) partial_len;
 488         return TARGET_XFER_OK;
 489       }
 490
 491     default:
 492       return TARGET_XFER_E_IO;
 493     }
 494 }
 495
 496 /* Wait for the child specified by PTID to do something.  Return the
 497    process ID of the child, or MINUS_ONE_PTID in case of error; store
 498    the status in *OURSTATUS.  */
 499
 500 ptid_t
 501 rs6000_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
 502                          target_wait_flags options)
 503 {
 504   pid_t pid;
 505   int status, save_errno;
 506
 507   do
 508     {
 509       set_sigint_trap ();
 510
 511       do
 512         {
 513           pid = waitpid (ptid.pid (), &status, 0);
 514           save_errno = errno;
 515         }
 516       while (pid == -1 && errno == EINTR);
 517
 518       clear_sigint_trap ();
 519
 520       if (pid == -1)
 521         {
 522           gdb_printf (gdb_stderr,
 523                       _("Child process unexpectedly missing: %s.\n"),
 524                       safe_strerror (save_errno));
 525
 526           /* Claim it exited with unknown signal.  */
 527           ourstatus->set_signalled (GDB_SIGNAL_UNKNOWN);
 528           return inferior_ptid;
 529         }
 530
 531       /* Ignore terminated detached child processes.  */
 532       if (!WIFSTOPPED (status) && pid != inferior_ptid.pid ())
 533         pid = -1;
 534     }
 535   while (pid == -1);
 536
 537   /* AIX has a couple of strange returns from wait().  */
 538
 539   /* stop after load" status.  */
 540   if (status == 0x57c)
 541     ourstatus->set_loaded ();
 542   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
 543   else if (status == 0x7f)
 544     ourstatus->set_spurious ();
 545   /* A normal waitstatus.  Let the usual macros deal with it.  */
 546   else
 547     *ourstatus = host_status_to_waitstatus (status);
 548
 549   return ptid_t (pid);
 550 }
 551 \f
 552
 553 /* Set the current architecture from the host running GDB.  Called when
 554    starting a child process.  */
 555
 556 void
 557 rs6000_nat_target::create_inferior (const char *exec_file,
 558                                     const std::string &allargs,
 559                                     char **env, int from_tty)
 560 {
 561   enum bfd_architecture arch;
 562   unsigned long mach;
 563   bfd abfd;
 564
 565   inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
 566
 567   if (__power_rs ())
 568     {
 569       arch = bfd_arch_rs6000;
 570       mach = bfd_mach_rs6k;
 571     }
 572   else
 573     {
 574       arch = bfd_arch_powerpc;
 575       mach = bfd_mach_ppc;
 576     }
 577
 578   /* FIXME: schauer/2002-02-25:
 579      We don't know if we are executing a 32 or 64 bit executable,
 580      and have no way to pass the proper word size to rs6000_gdbarch_init.
 581      So we have to avoid switching to a new architecture, if the architecture
 582      matches already.
 583      Blindly calling rs6000_gdbarch_init used to work in older versions of
 584      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
 585      determine the wordsize.  */
 586   if (current_program_space->exec_bfd ())
 587     {
 588       const struct bfd_arch_info *exec_bfd_arch_info;
 589
 590       exec_bfd_arch_info
 591         = bfd_get_arch_info (current_program_space->exec_bfd ());
 592       if (arch == exec_bfd_arch_info->arch)
 593         return;
 594     }
 595
 596   bfd_default_set_arch_mach (&abfd, arch, mach);
 597
 598   gdbarch_info info;
 599   info.bfd_arch_info = bfd_get_arch_info (&abfd);
 600   info.abfd = current_program_space->exec_bfd ();
 601
 602   if (!gdbarch_update_p (info))
 603     internal_error (__FILE__, __LINE__,
 604                     _("rs6000_create_inferior: failed "
 605                       "to select architecture"));
 606 }
 607 \f
 608
 609 /* Shared Object support.  */
 610
 611 /* Return the LdInfo data for the given process.  Raises an error
 612    if the data could not be obtained.  */
 613
 614 static gdb::byte_vector
 615 rs6000_ptrace_ldinfo (ptid_t ptid)
 616 {
 617   const int pid = ptid.pid ();
 618   gdb::byte_vector ldi (1024);
 619   int rc = -1;
 620
 621   while (1)
 622     {
 623       if (ARCH64 ())
 624         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi.data (),
 625                               ldi.size (), NULL);
 626       else
 627         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi.data (),
 628                               ldi.size (), NULL);
 629
 630       if (rc != -1)
 631         break; /* Success, we got the entire ld_info data.  */
 632
 633       if (errno != ENOMEM)
 634         perror_with_name (_("ptrace ldinfo"));
 635
 636       /* ldi is not big enough.  Double it and try again.  */
 637       ldi.resize (ldi.size () * 2);
 638     }
 639
 640   return ldi;
 641 }
 642
 643 /* Implement the to_xfer_partial target_ops method for
 644    TARGET_OBJECT_LIBRARIES_AIX objects.  */
 645
 646 enum target_xfer_status
 647 rs6000_nat_target::xfer_shared_libraries
 648   (enum target_object object,
 649    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
 650    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
 651 {
 652   ULONGEST result;
 653
 654   /* This function assumes that it is being run with a live process.
 655      Core files are handled via gdbarch.  */
 656   gdb_assert (target_has_execution ());
 657
 658   if (writebuf)
 659     return TARGET_XFER_E_IO;
 660
 661   gdb::byte_vector ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
 662   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf.data (),
 663                                       readbuf, offset, len, 1);
 664
 665   if (result == 0)
 666     return TARGET_XFER_EOF;
 667   else
 668     {
 669       *xfered_len = result;
 670       return TARGET_XFER_OK;
 671     }
 672 }
 673
 674 void _initialize_rs6000_nat ();
 675 void
 676 _initialize_rs6000_nat ()
 677 {
 678   add_inf_child_target (&the_rs6000_nat_target);
 679 }