gdb/rs6000-nat.c - gdb

Global variables defined

Functions defined

Macros defined

Source code

  1. /* IBM RS/6000 native-dependent code for GDB, the GNU debugger.

  3.    Copyright (C) 1986-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  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.

  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.

  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/>.  */

  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 "gdb-stabs.h"
  29. #include "regcache.h"
  30. #include "arch-utils.h"
  31. #include "inf-child.h"
  32. #include "inf-ptrace.h"
  33. #include "ppc-tdep.h"
  34. #include "rs6000-tdep.h"
  35. #include "rs6000-aix-tdep.h"
  36. #include "exec.h"
  37. #include "observer.h"
  38. #include "xcoffread.h"

  40. #include <sys/ptrace.h>
  41. #include <sys/reg.h>

  43. #include <sys/dir.h>
  44. #include <sys/user.h>
  45. #include <signal.h>
  46. #include <sys/ioctl.h>
  47. #include <fcntl.h>

  49. #include <a.out.h>
  50. #include <sys/file.h>
  51. #include <sys/stat.h>
  52. #include "gdb_bfd.h"
  53. #include <sys/core.h>
  54. ‌#define __LDINFO_PTRACE32__        /* for __ld_info32 */
  55. ‌#define __LDINFO_PTRACE64__        /* for __ld_info64 */
  56. #include <sys/ldr.h>
  57. #include <sys/systemcfg.h>

  59. /* On AIX4.3+, sys/ldr.h provides different versions of struct ld_info for
  60.    debugging 32-bit and 64-bit processes.  Define a typedef and macros for
  61.    accessing fields in the appropriate structures.  */

  63. /* In 32-bit compilation mode (which is the only mode from which ptrace()
  64.    works on 4.3), __ld_info32 is #defined as equivalent to ld_info.  */

  66. #if defined (__ld_info32) || defined (__ld_info64)
  67. ‌# define ARCH3264
  68. #endif

  70. /* Return whether the current architecture is 64-bit.  */

  72. #ifndef ARCH3264
  73. ‌# define ARCH64() 0
  74. #else
  75. ‌# define ARCH64() (register_size (target_gdbarch (), 0) == 8)
  76. #endif

  78. ‌static target_xfer_partial_ftype rs6000_xfer_shared_libraries;

  80. /* Given REGNO, a gdb register number, return the corresponding
  81.    number suitable for use as a ptrace() parameter.  Return -1 if
  82.    there's no suitable mapping.  Also, set the int pointed to by
  83.    ISFLOAT to indicate whether REGNO is a floating point register.  */

  85. static int
  86. ‌regmap (struct gdbarch *gdbarch, int regno, int *isfloat)
  87. {
  88.   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  90.   *isfloat = 0;
  91.   if (tdep->ppc_gp0_regnum <= regno
  92.       && regno < tdep->ppc_gp0_regnum + ppc_num_gprs)
  93.     return regno;
  94.   else if (tdep->ppc_fp0_regnum >= 0
  95.            && tdep->ppc_fp0_regnum <= regno
  96.            && regno < tdep->ppc_fp0_regnum + ppc_num_fprs)
  97.     {
  98.       *isfloat = 1;
  99.       return regno - tdep->ppc_fp0_regnum + FPR0;
  100.     }
  101.   else if (regno == gdbarch_pc_regnum (gdbarch))
  102.     return IAR;
  103.   else if (regno == tdep->ppc_ps_regnum)
  104.     return MSR;
  105.   else if (regno == tdep->ppc_cr_regnum)
  106.     return CR;
  107.   else if (regno == tdep->ppc_lr_regnum)
  108.     return LR;
  109.   else if (regno == tdep->ppc_ctr_regnum)
  110.     return CTR;
  111.   else if (regno == tdep->ppc_xer_regnum)
  112.     return XER;
  113.   else if (tdep->ppc_fpscr_regnum >= 0
  114.            && regno == tdep->ppc_fpscr_regnum)
  115.     return FPSCR;
  116.   else if (tdep->ppc_mq_regnum >= 0 && regno == tdep->ppc_mq_regnum)
  117.     return MQ;
  118.   else
  119.     return -1;
  120. }

  122. /* Call ptrace(REQ, ID, ADDR, DATA, BUF).  */

  124. static int
  125. ‌rs6000_ptrace32 (int req, int id, int *addr, int data, int *buf)
  126. {
  127. #ifdef HAVE_PTRACE64
  128.   int ret = ptrace64 (req, id, (uintptr_t) addr, data, buf);
  129. #else
  130.   int ret = ptrace (req, id, (int *)addr, data, buf);
  131. #endif
  132. #if 0
  133.   printf ("rs6000_ptrace32 (%d, %d, 0x%x, %08x, 0x%x) = 0x%x\n",
  134.           req, id, (unsigned int)addr, data, (unsigned int)buf, ret);
  135. #endif
  136.   return ret;
  137. }

  139. /* Call ptracex(REQ, ID, ADDR, DATA, BUF).  */

  141. static int
  142. ‌rs6000_ptrace64 (int req, int id, long long addr, int data, void *buf)
  143. {
  144. #ifdef ARCH3264
  145. #  ifdef HAVE_PTRACE64
  146.   int ret = ptrace64 (req, id, addr, data, buf);
  147. #  else
  148.   int ret = ptracex (req, id, addr, data, buf);
  149. #  endif
  150. #else
  151.   int ret = 0;
  152. #endif
  153. #if 0
  154.   printf ("rs6000_ptrace64 (%d, %d, %s, %08x, 0x%x) = 0x%x\n",
  155.           req, id, hex_string (addr), data, (unsigned int)buf, ret);
  156. #endif
  157.   return ret;
  158. }

  160. /* Fetch register REGNO from the inferior.  */

  162. static void
  163. ‌fetch_register (struct regcache *regcache, int regno)
  164. {
  165.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  166.   int addr[MAX_REGISTER_SIZE];
  167.   int nr, isfloat;

  169.   /* Retrieved values may be -1, so infer errors from errno.  */
  170.   errno = 0;

  172.   nr = regmap (gdbarch, regno, &isfloat);

  174.   /* Floating-point registers.  */
  175.   if (isfloat)
  176.     rs6000_ptrace32 (PT_READ_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);

  178.   /* Bogus register number.  */
  179.   else if (nr < 0)
  180.     {
  181.       if (regno >= gdbarch_num_regs (gdbarch))
  182.         fprintf_unfiltered (gdb_stderr,
  183.                             "gdb error: register no %d not implemented.\n",
  184.                             regno);
  185.       return;
  186.     }

  188.   /* Fixed-point registers.  */
  189.   else
  190.     {
  191.       if (!ARCH64 ())
  192.         *addr = rs6000_ptrace32 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
  193.                                  (int *) nr, 0, 0);
  194.       else
  195.         {
  196.           /* PT_READ_GPR requires the buffer parameter to point to long long,
  197.              even if the register is really only 32 bits.  */
  198.           long long buf;
  199.           rs6000_ptrace64 (PT_READ_GPR, ptid_get_pid (inferior_ptid),
  200.                            nr, 0, &buf);
  201.           if (register_size (gdbarch, regno) == 8)
  202.             memcpy (addr, &buf, 8);
  203.           else
  204.             *addr = buf;
  205.         }
  206.     }

  208.   if (!errno)
  209.     regcache_raw_supply (regcache, regno, (char *) addr);
  210.   else
  211.     {
  212. #if 0
  213.       /* FIXME: this happens 3 times at the start of each 64-bit program.  */
  214.       perror (_("ptrace read"));
  215. #endif
  216.       errno = 0;
  217.     }
  218. }

  220. /* Store register REGNO back into the inferior.  */

  222. static void
  223. ‌store_register (struct regcache *regcache, int regno)
  224. {
  225.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  226.   int addr[MAX_REGISTER_SIZE];
  227.   int nr, isfloat;

  229.   /* Fetch the register's value from the register cache.  */
  230.   regcache_raw_collect (regcache, regno, addr);

  232.   /* -1 can be a successful return value, so infer errors from errno.  */
  233.   errno = 0;

  235.   nr = regmap (gdbarch, regno, &isfloat);

  237.   /* Floating-point registers.  */
  238.   if (isfloat)
  239.     rs6000_ptrace32 (PT_WRITE_FPR, ptid_get_pid (inferior_ptid), addr, nr, 0);

  241.   /* Bogus register number.  */
  242.   else if (nr < 0)
  243.     {
  244.       if (regno >= gdbarch_num_regs (gdbarch))
  245.         fprintf_unfiltered (gdb_stderr,
  246.                             "gdb error: register no %d not implemented.\n",
  247.                             regno);
  248.     }

  250.   /* Fixed-point registers.  */
  251.   else
  252.     {
  253.       /* The PT_WRITE_GPR operation is rather odd.  For 32-bit inferiors,
  254.          the register's value is passed by value, but for 64-bit inferiors,
  255.          the address of a buffer containing the value is passed.  */
  256.       if (!ARCH64 ())
  257.         rs6000_ptrace32 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
  258.                          (int *) nr, *addr, 0);
  259.       else
  260.         {
  261.           /* PT_WRITE_GPR requires the buffer parameter to point to an 8-byte
  262.              area, even if the register is really only 32 bits.  */
  263.           long long buf;
  264.           if (register_size (gdbarch, regno) == 8)
  265.             memcpy (&buf, addr, 8);
  266.           else
  267.             buf = *addr;
  268.           rs6000_ptrace64 (PT_WRITE_GPR, ptid_get_pid (inferior_ptid),
  269.                            nr, 0, &buf);
  270.         }
  271.     }

  273.   if (errno)
  274.     {
  275.       perror (_("ptrace write"));
  276.       errno = 0;
  277.     }
  278. }

  280. /* Read from the inferior all registers if REGNO == -1 and just register
  281.    REGNO otherwise.  */

  283. static void
  284. ‌rs6000_fetch_inferior_registers (struct target_ops *ops,
  285.                                  struct regcache *regcache, int regno)
  286. {
  287.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  288.   if (regno != -1)
  289.     fetch_register (regcache, regno);

  291.   else
  292.     {
  293.       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  295.       /* Read 32 general purpose registers.  */
  296.       for (regno = tdep->ppc_gp0_regnum;
  297.            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
  298.            regno++)
  299.         {
  300.           fetch_register (regcache, regno);
  301.         }

  303.       /* Read general purpose floating point registers.  */
  304.       if (tdep->ppc_fp0_regnum >= 0)
  305.         for (regno = 0; regno < ppc_num_fprs; regno++)
  306.           fetch_register (regcache, tdep->ppc_fp0_regnum + regno);

  308.       /* Read special registers.  */
  309.       fetch_register (regcache, gdbarch_pc_regnum (gdbarch));
  310.       fetch_register (regcache, tdep->ppc_ps_regnum);
  311.       fetch_register (regcache, tdep->ppc_cr_regnum);
  312.       fetch_register (regcache, tdep->ppc_lr_regnum);
  313.       fetch_register (regcache, tdep->ppc_ctr_regnum);
  314.       fetch_register (regcache, tdep->ppc_xer_regnum);
  315.       if (tdep->ppc_fpscr_regnum >= 0)
  316.         fetch_register (regcache, tdep->ppc_fpscr_regnum);
  317.       if (tdep->ppc_mq_regnum >= 0)
  318.         fetch_register (regcache, tdep->ppc_mq_regnum);
  319.     }
  320. }

  322. /* Store our register values back into the inferior.
  323.    If REGNO is -1, do this for all registers.
  324.    Otherwise, REGNO specifies which register (so we can save time).  */

  326. static void
  327. ‌rs6000_store_inferior_registers (struct target_ops *ops,
  328.                                  struct regcache *regcache, int regno)
  329. {
  330.   struct gdbarch *gdbarch = get_regcache_arch (regcache);
  331.   if (regno != -1)
  332.     store_register (regcache, regno);

  334.   else
  335.     {
  336.       struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  338.       /* Write general purpose registers first.  */
  339.       for (regno = tdep->ppc_gp0_regnum;
  340.            regno < tdep->ppc_gp0_regnum + ppc_num_gprs;
  341.            regno++)
  342.         {
  343.           store_register (regcache, regno);
  344.         }

  346.       /* Write floating point registers.  */
  347.       if (tdep->ppc_fp0_regnum >= 0)
  348.         for (regno = 0; regno < ppc_num_fprs; regno++)
  349.           store_register (regcache, tdep->ppc_fp0_regnum + regno);

  351.       /* Write special registers.  */
  352.       store_register (regcache, gdbarch_pc_regnum (gdbarch));
  353.       store_register (regcache, tdep->ppc_ps_regnum);
  354.       store_register (regcache, tdep->ppc_cr_regnum);
  355.       store_register (regcache, tdep->ppc_lr_regnum);
  356.       store_register (regcache, tdep->ppc_ctr_regnum);
  357.       store_register (regcache, tdep->ppc_xer_regnum);
  358.       if (tdep->ppc_fpscr_regnum >= 0)
  359.         store_register (regcache, tdep->ppc_fpscr_regnum);
  360.       if (tdep->ppc_mq_regnum >= 0)
  361.         store_register (regcache, tdep->ppc_mq_regnum);
  362.     }
  363. }

  365. /* Implement the to_xfer_partial target_ops method.  */

  367. static enum target_xfer_status
  368. ‌rs6000_xfer_partial (struct target_ops *ops, enum target_object object,
  369.                      const char *annex, gdb_byte *readbuf,
  370.                      const gdb_byte *writebuf,
  371.                      ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
  372. {
  373.   pid_t pid = ptid_get_pid (inferior_ptid);
  374.   int arch64 = ARCH64 ();

  376.   switch (object)
  377.     {
  378.     case TARGET_OBJECT_LIBRARIES_AIX:
  379.       return rs6000_xfer_shared_libraries (ops, object, annex,
  380.                                            readbuf, writebuf,
  381.                                            offset, len, xfered_len);
  382.     case TARGET_OBJECT_MEMORY:
  383.       {
  384.         union
  385.         {
  386.           PTRACE_TYPE_RET word;
  387.           gdb_byte byte[sizeof (PTRACE_TYPE_RET)];
  388.         } buffer;
  389.         ULONGEST rounded_offset;
  390.         LONGEST partial_len;

  392.         /* Round the start offset down to the next long word
  393.            boundary.  */
  394.         rounded_offset = offset & -(ULONGEST) sizeof (PTRACE_TYPE_RET);

  396.         /* Since ptrace will transfer a single word starting at that
  397.            rounded_offset the partial_len needs to be adjusted down to
  398.            that (remember this function only does a single transfer).
  399.            Should the required length be even less, adjust it down
  400.            again.  */
  401.         partial_len = (rounded_offset + sizeof (PTRACE_TYPE_RET)) - offset;
  402.         if (partial_len > len)
  403.           partial_len = len;

  405.         if (writebuf)
  406.           {
  407.             /* If OFFSET:PARTIAL_LEN is smaller than
  408.                ROUNDED_OFFSET:WORDSIZE then a read/modify write will
  409.                be needed.  Read in the entire word.  */
  410.             if (rounded_offset < offset
  411.                 || (offset + partial_len
  412.                     < rounded_offset + sizeof (PTRACE_TYPE_RET)))
  413.               {
  414.                 /* Need part of initial word -- fetch it.  */
  415.                 if (arch64)
  416.                   buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
  417.                                                  rounded_offset, 0, NULL);
  418.                 else
  419.                   buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
  420.                                                  (int *) (uintptr_t)
  421.                                                  rounded_offset,
  422.                                                  0, NULL);
  423.               }

  425.             /* Copy data to be written over corresponding part of
  426.                buffer.  */
  427.             memcpy (buffer.byte + (offset - rounded_offset),
  428.                     writebuf, partial_len);

  430.             errno = 0;
  431.             if (arch64)
  432.               rs6000_ptrace64 (PT_WRITE_D, pid,
  433.                                rounded_offset, buffer.word, NULL);
  434.             else
  435.               rs6000_ptrace32 (PT_WRITE_D, pid,
  436.                                (int *) (uintptr_t) rounded_offset,
  437.                                buffer.word, NULL);
  438.             if (errno)
  439.               return TARGET_XFER_EOF;
  440.           }

  442.         if (readbuf)
  443.           {
  444.             errno = 0;
  445.             if (arch64)
  446.               buffer.word = rs6000_ptrace64 (PT_READ_I, pid,
  447.                                              rounded_offset, 0, NULL);
  448.             else
  449.               buffer.word = rs6000_ptrace32 (PT_READ_I, pid,
  450.                                              (int *)(uintptr_t)rounded_offset,
  451.                                              0, NULL);
  452.             if (errno)
  453.               return TARGET_XFER_EOF;

  455.             /* Copy appropriate bytes out of the buffer.  */
  456.             memcpy (readbuf, buffer.byte + (offset - rounded_offset),
  457.                     partial_len);
  458.           }

  460.         *xfered_len = (ULONGEST) partial_len;
  461.         return TARGET_XFER_OK;
  462.       }

  464.     default:
  465.       return TARGET_XFER_E_IO;
  466.     }
  467. }

  469. /* Wait for the child specified by PTID to do something.  Return the
  470.    process ID of the child, or MINUS_ONE_PTID in case of error; store
  471.    the status in *OURSTATUS.  */

  473. static ptid_t
  474. ‌rs6000_wait (struct target_ops *ops,
  475.              ptid_t ptid, struct target_waitstatus *ourstatus, int options)
  476. {
  477.   pid_t pid;
  478.   int status, save_errno;

  480.   do
  481.     {
  482.       set_sigint_trap ();

  484.       do
  485.         {
  486.           pid = waitpid (ptid_get_pid (ptid), &status, 0);
  487.           save_errno = errno;
  488.         }
  489.       while (pid == -1 && errno == EINTR);

  491.       clear_sigint_trap ();

  493.       if (pid == -1)
  494.         {
  495.           fprintf_unfiltered (gdb_stderr,
  496.                               _("Child process unexpectedly missing: %s.\n"),
  497.                               safe_strerror (save_errno));

  499.           /* Claim it exited with unknown signal.  */
  500.           ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
  501.           ourstatus->value.sig = GDB_SIGNAL_UNKNOWN;
  502.           return inferior_ptid;
  503.         }

  505.       /* Ignore terminated detached child processes.  */
  506.       if (!WIFSTOPPED (status) && pid != ptid_get_pid (inferior_ptid))
  507.         pid = -1;
  508.     }
  509.   while (pid == -1);

  511.   /* AIX has a couple of strange returns from wait().  */

  513.   /* stop after load" status.  */
  514.   if (status == 0x57c)
  515.     ourstatus->kind = TARGET_WAITKIND_LOADED;
  516.   /* signal 0.  I have no idea why wait(2) returns with this status word.  */
  517.   else if (status == 0x7f)
  518.     ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
  519.   /* A normal waitstatus.  Let the usual macros deal with it.  */
  520.   else
  521.     store_waitstatus (ourstatus, status);

  523.   return pid_to_ptid (pid);
  524. }


  527. /* Set the current architecture from the host running GDB.  Called when
  528.    starting a child process.  */

  530. ‌static void (*super_create_inferior) (struct target_ops *,char *exec_file,
  531.                                       char *allargs, char **env, int from_tty);
  532. static void
  533. ‌rs6000_create_inferior (struct target_ops * ops, char *exec_file,
  534.                         char *allargs, char **env, int from_tty)
  535. {
  536.   enum bfd_architecture arch;
  537.   unsigned long mach;
  538.   bfd abfd;
  539.   struct gdbarch_info info;

  541.   super_create_inferior (ops, exec_file, allargs, env, from_tty);

  543.   if (__power_rs ())
  544.     {
  545.       arch = bfd_arch_rs6000;
  546.       mach = bfd_mach_rs6k;
  547.     }
  548.   else
  549.     {
  550.       arch = bfd_arch_powerpc;
  551.       mach = bfd_mach_ppc;
  552.     }

  554.   /* FIXME: schauer/2002-02-25:
  555.      We don't know if we are executing a 32 or 64 bit executable,
  556.      and have no way to pass the proper word size to rs6000_gdbarch_init.
  557.      So we have to avoid switching to a new architecture, if the architecture
  558.      matches already.
  559.      Blindly calling rs6000_gdbarch_init used to work in older versions of
  560.      GDB, as rs6000_gdbarch_init incorrectly used the previous tdep to
  561.      determine the wordsize.  */
  562.   if (exec_bfd)
  563.     {
  564.       const struct bfd_arch_info *exec_bfd_arch_info;

  566.       exec_bfd_arch_info = bfd_get_arch_info (exec_bfd);
  567.       if (arch == exec_bfd_arch_info->arch)
  568.         return;
  569.     }

  571.   bfd_default_set_arch_mach (&abfd, arch, mach);

  573.   gdbarch_info_init (&info);
  574.   info.bfd_arch_info = bfd_get_arch_info (&abfd);
  575.   info.abfd = exec_bfd;

  577.   if (!gdbarch_update_p (info))
  578.     internal_error (__FILE__, __LINE__,
  579.                     _("rs6000_create_inferior: failed "
  580.                       "to select architecture"));
  581. }


  584. /* Shared Object support.  */

  586. /* Return the LdInfo data for the given process.  Raises an error
  587.    if the data could not be obtained.

  589.    The returned value must be deallocated after use.  */

  591. static gdb_byte *
  592. ‌rs6000_ptrace_ldinfo (ptid_t ptid)
  593. {
  594.   const int pid = ptid_get_pid (ptid);
  595.   int ldi_size = 1024;
  596.   gdb_byte *ldi = xmalloc (ldi_size);
  597.   int rc = -1;

  599.   while (1)
  600.     {
  601.       if (ARCH64 ())
  602.         rc = rs6000_ptrace64 (PT_LDINFO, pid, (unsigned long) ldi, ldi_size,
  603.                               NULL);
  604.       else
  605.         rc = rs6000_ptrace32 (PT_LDINFO, pid, (int *) ldi, ldi_size, NULL);

  607.       if (rc != -1)
  608.         break; /* Success, we got the entire ld_info data.  */

  610.       if (errno != ENOMEM)
  611.         perror_with_name (_("ptrace ldinfo"));

  613.       /* ldi is not big enough.  Double it and try again.  */
  614.       ldi_size *= 2;
  615.       ldi = xrealloc (ldi, ldi_size);
  616.     }

  618.   return ldi;
  619. }

  621. /* Implement the to_xfer_partial target_ops method for
  622.    TARGET_OBJECT_LIBRARIES_AIX objects.  */

  624. static enum target_xfer_status
  625. ‌rs6000_xfer_shared_libraries
  626.   (struct target_ops *ops, enum target_object object,
  627.    const char *annex, gdb_byte *readbuf, const gdb_byte *writebuf,
  628.    ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
  629. {
  630.   gdb_byte *ldi_buf;
  631.   ULONGEST result;
  632.   struct cleanup *cleanup;

  634.   /* This function assumes that it is being run with a live process.
  635.      Core files are handled via gdbarch.  */
  636.   gdb_assert (target_has_execution);

  638.   if (writebuf)
  639.     return TARGET_XFER_E_IO;

  641.   ldi_buf = rs6000_ptrace_ldinfo (inferior_ptid);
  642.   gdb_assert (ldi_buf != NULL);
  643.   cleanup = make_cleanup (xfree, ldi_buf);
  644.   result = rs6000_aix_ld_info_to_xml (target_gdbarch (), ldi_buf,
  645.                                       readbuf, offset, len, 1);
  646.   xfree (ldi_buf);

  648.   do_cleanups (cleanup);

  650.   if (result == 0)
  651.     return TARGET_XFER_EOF;
  652.   else
  653.     {
  654.       *xfered_len = result;
  655.       return TARGET_XFER_OK;
  656.     }
  657. }

  659. void _initialize_rs6000_nat (void);

  661. void
  662. ‌_initialize_rs6000_nat (void)
  663. {
  664.   struct target_ops *t;

  666.   t = inf_ptrace_target ();
  667.   t->to_fetch_registers = rs6000_fetch_inferior_registers;
  668.   t->to_store_registers = rs6000_store_inferior_registers;
  669.   t->to_xfer_partial = rs6000_xfer_partial;

  671.   super_create_inferior = t->to_create_inferior;
  672.   t->to_create_inferior = rs6000_create_inferior;

  674.   t->to_wait = rs6000_wait;

  676.   add_target (t);
  677. }