[thirdparty/binutils-gdb.git] / gdb / sparc-nat.c

/* Native-dependent code for SPARC.

   Copyright (C) 2003-2025 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "inferior.h"
#include "regcache.h"
#include "target.h"

#include <signal.h>
#include <sys/ptrace.h>
#include "gdbsupport/gdb_wait.h"
#ifdef HAVE_MACHINE_REG_H
#include <machine/reg.h>
#endif

#include "sparc-tdep.h"
#include "sparc-nat.h"
#include "inf-ptrace.h"

/* With some trickery we can use the code in this file for most (if
   not all) ptrace(2) based SPARC systems, which includes SunOS 4,
   GNU/Linux and the various SPARC BSD's.

   First, we need a data structure for use with ptrace(2).  SunOS has
   `struct regs' and `struct fp_status' in <machine/reg.h>.  BSD's
   have `struct reg' and `struct fpreg' in <machine/reg.h>.  GNU/Linux
   has the same structures as SunOS 4, but they're in <asm/reg.h>,
   which is a kernel header.  As a general rule we avoid including
   GNU/Linux kernel headers.  Fortunately GNU/Linux has a `gregset_t'
   and a `fpregset_t' that are equivalent to `struct regs' and `struct
   fp_status' in <sys/ucontext.h>, which is automatically included by
   <signal.h>.  Settling on using the `gregset_t' and `fpregset_t'
   typedefs, providing them for the other systems, therefore solves
   the puzzle.  */

#ifdef HAVE_MACHINE_REG_H
#ifdef HAVE_STRUCT_REG
typedef struct reg gregset_t;
typedef struct fpreg fpregset_t;
#else 
typedef struct regs gregset_t;
typedef struct fp_status fpregset_t;
#endif
#endif

/* Second, we need to remap the BSD ptrace(2) requests to their SunOS
   equivalents.  GNU/Linux already follows SunOS here.  */

#ifndef PTRACE_GETREGS
#define PTRACE_GETREGS PT_GETREGS
#endif

#ifndef PTRACE_SETREGS
#define PTRACE_SETREGS PT_SETREGS
#endif

#ifndef PTRACE_GETFPREGS
#define PTRACE_GETFPREGS PT_GETFPREGS
#endif

#ifndef PTRACE_SETFPREGS
#define PTRACE_SETFPREGS PT_SETFPREGS
#endif

static PTRACE_TYPE_RET
gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
{
#ifdef __NetBSD__
  /* Support for NetBSD threads: unlike other ptrace implementations in this
     file, NetBSD requires that we pass both the pid and lwp.  */
  return ptrace (request, ptid.pid (), addr, ptid.lwp ());
#else
  pid_t pid = get_ptrace_pid (ptid);
  return ptrace (request, pid, addr, 0);
#endif
}

/* Register set description.  */
const struct sparc_gregmap *sparc_gregmap;
const struct sparc_fpregmap *sparc_fpregmap;
void (*sparc_supply_gregset) (const struct sparc_gregmap *,
			      struct regcache *, int , const void *);
void (*sparc_collect_gregset) (const struct sparc_gregmap *,
			       const struct regcache *, int, void *);
void (*sparc_supply_fpregset) (const struct sparc_fpregmap *,
			       struct regcache *, int , const void *);
void (*sparc_collect_fpregset) (const struct sparc_fpregmap *,
				const struct regcache *, int , void *);
int (*sparc_gregset_supplies_p) (struct gdbarch *, int);
int (*sparc_fpregset_supplies_p) (struct gdbarch *, int);

/* Determine whether `gregset_t' contains register REGNUM.  */

int
sparc32_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
{
  /* Integer registers.  */
  if ((regnum >= SPARC_G1_REGNUM && regnum <= SPARC_G7_REGNUM)
      || (regnum >= SPARC_O0_REGNUM && regnum <= SPARC_O7_REGNUM)
      || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_L7_REGNUM)
      || (regnum >= SPARC_I0_REGNUM && regnum <= SPARC_I7_REGNUM))
    return 1;

  /* Control registers.  */
  if (regnum == SPARC32_PC_REGNUM
      || regnum == SPARC32_NPC_REGNUM
      || regnum == SPARC32_PSR_REGNUM
      || regnum == SPARC32_Y_REGNUM)
    return 1;

  return 0;
}

/* Determine whether `fpregset_t' contains register REGNUM.  */

int
sparc32_fpregset_supplies_p (struct gdbarch *gdbarch, int regnum)
{
  /* Floating-point registers.  */
  if (regnum >= SPARC_F0_REGNUM && regnum <= SPARC_F31_REGNUM)
    return 1;

  /* Control registers.  */
  if (regnum == SPARC32_FSR_REGNUM)
    return 1;

  return 0;
}

/* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
   for all registers (including the floating-point registers).  */

void
sparc_fetch_inferior_registers (process_stratum_target *proc_target,
				regcache *regcache, int regnum)
{
  struct gdbarch *gdbarch = regcache->arch ();
  ptid_t ptid = regcache->ptid ();

  if (regnum == SPARC_G0_REGNUM)
    {
      regcache->raw_supply_zeroed (SPARC_G0_REGNUM);
      return;
    }

  if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
    {
      gregset_t regs;

      if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	perror_with_name (_("Couldn't get registers"));

      /* Deep down, sparc_supply_rwindow reads memory, so needs the global
	 thread context to be set.  */
      scoped_restore restore_inferior_ptid
	= make_scoped_restore (&inferior_ptid, ptid);

      sparc_supply_gregset (sparc_gregmap, regcache, -1, &regs);
      if (regnum != -1)
	return;
    }

  if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
    {
      fpregset_t fpregs;

      if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
	perror_with_name (_("Couldn't get floating point status"));

      sparc_supply_fpregset (sparc_fpregmap, regcache, -1, &fpregs);
    }
}

void
sparc_store_inferior_registers (process_stratum_target *proc_target,
				regcache *regcache, int regnum)
{
  struct gdbarch *gdbarch = regcache->arch ();
  ptid_t ptid = regcache->ptid ();

  if (regnum == -1 || sparc_gregset_supplies_p (gdbarch, regnum))
    {
      gregset_t regs;

      if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	perror_with_name (_("Couldn't get registers"));

      sparc_collect_gregset (sparc_gregmap, regcache, regnum, &regs);

      if (gdb_ptrace (PTRACE_SETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	perror_with_name (_("Couldn't write registers"));

      /* Deal with the stack regs.  */
      if (regnum == -1 || regnum == SPARC_SP_REGNUM
	  || (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
	{
	  ULONGEST sp;

	  regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);

	  /* Deep down, sparc_collect_rwindow writes memory, so needs the global
	     thread context to be set.  */
	  scoped_restore restore_inferior_ptid
	    = make_scoped_restore (&inferior_ptid, ptid);

	  sparc_collect_rwindow (regcache, sp, regnum);
	}

      if (regnum != -1)
	return;
    }

  if (regnum == -1 || sparc_fpregset_supplies_p (gdbarch, regnum))
    {
      fpregset_t fpregs, saved_fpregs;

      if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
	perror_with_name (_("Couldn't get floating-point registers"));

      memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
      sparc_collect_fpregset (sparc_fpregmap, regcache, regnum, &fpregs);

      /* Writing the floating-point registers will fail on NetBSD with
	 EINVAL if the inferior process doesn't have an FPU state
	 (i.e. if it didn't use the FPU yet).  Therefore we don't try
	 to write the registers if nothing changed.  */
      if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
	{
	  if (gdb_ptrace (PTRACE_SETFPREGS, ptid,
			  (PTRACE_TYPE_ARG3) &fpregs) == -1)
	    perror_with_name (_("Couldn't write floating-point registers"));
	}

      if (regnum != -1)
	return;
    }
}

\f
/* Implement the to_xfer_partial target_ops method for
   TARGET_OBJECT_WCOOKIE.  Fetch StackGhost Per-Process XOR cookie.  */

enum target_xfer_status
sparc_xfer_wcookie (enum target_object object,
		    const char *annex, gdb_byte *readbuf,
		    const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
		    ULONGEST *xfered_len)
{
  unsigned long wcookie = 0;
  char *buf = (char *)&wcookie;

  gdb_assert (object == TARGET_OBJECT_WCOOKIE);
  gdb_assert (readbuf && writebuf == NULL);

  if (offset == sizeof (unsigned long))
    return TARGET_XFER_EOF;			/* Signal EOF.  */
  if (offset > sizeof (unsigned long))
    return TARGET_XFER_E_IO;

#ifdef PT_WCOOKIE
  /* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
     running on an OpenBSD release that uses StackGhost (3.1 or
     later).  Since release 3.6, OpenBSD uses a fully randomized
     cookie.  */
  {
    int pid = inferior_ptid.pid ();

    /* Sanity check.  The proper type for a cookie is register_t, but
       we can't assume that this type exists on all systems supported
       by the code in this file.  */
    gdb_assert (sizeof (wcookie) == sizeof (register_t));

    /* Fetch the cookie.  */
    if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
      {
	if (errno != EINVAL)
	  perror_with_name (_("Couldn't get StackGhost cookie"));

	/* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
	   the request wasn't implemented until after OpenBSD 3.4.  If
	   the kernel doesn't support the PT_WCOOKIE request, assume
	   we're running on a kernel that uses non-randomized cookies.  */
	wcookie = 0x3;
      }
  }
#endif /* PT_WCOOKIE */

  if (len > sizeof (unsigned long) - offset)
    len = sizeof (unsigned long) - offset;

  memcpy (readbuf, buf + offset, len);
  *xfered_len = (ULONGEST) len;
  return TARGET_XFER_OK;
}
\f

INIT_GDB_FILE (sparc_nat)
{
  /* Default to using SunOS 4 register sets.  */
  if (sparc_gregmap == NULL)
    sparc_gregmap = &sparc32_sunos4_gregmap;
  if (sparc_fpregmap == NULL)
    sparc_fpregmap = &sparc32_sunos4_fpregmap;
  if (sparc_supply_gregset == NULL)
    sparc_supply_gregset = sparc32_supply_gregset;
  if (sparc_collect_gregset == NULL)
    sparc_collect_gregset = sparc32_collect_gregset;
  if (sparc_supply_fpregset == NULL)
    sparc_supply_fpregset = sparc32_supply_fpregset;
  if (sparc_collect_fpregset == NULL)
    sparc_collect_fpregset = sparc32_collect_fpregset;
  if (sparc_gregset_supplies_p == NULL)
    sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
  if (sparc_fpregset_supplies_p == NULL)
    sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
}
Commit	Line	Data
	1	/* Native-dependent code for SPARC.
	2
	3	Copyright (C) 2003-2025 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 "inferior.h"
	21	#include "regcache.h"
	22	#include "target.h"
	23
	24	#include <signal.h>
	25	#include <sys/ptrace.h>
	26	#include "gdbsupport/gdb_wait.h"
	27	#ifdef HAVE_MACHINE_REG_H
	28	#include <machine/reg.h>
	29	#endif
	30
	31	#include "sparc-tdep.h"
	32	#include "sparc-nat.h"
	33	#include "inf-ptrace.h"
	34
	35	/* With some trickery we can use the code in this file for most (if
	36	not all) ptrace(2) based SPARC systems, which includes SunOS 4,
	37	GNU/Linux and the various SPARC BSD's.
	38
	39	First, we need a data structure for use with ptrace(2). SunOS has
	40	`struct regs' and `struct fp_status' in <machine/reg.h>. BSD's
	41	have `struct reg' and `struct fpreg' in <machine/reg.h>. GNU/Linux
	42	has the same structures as SunOS 4, but they're in <asm/reg.h>,
	43	which is a kernel header. As a general rule we avoid including
	44	GNU/Linux kernel headers. Fortunately GNU/Linux has a `gregset_t'
	45	and a `fpregset_t' that are equivalent to `struct regs' and `struct
	46	fp_status' in <sys/ucontext.h>, which is automatically included by
	47	<signal.h>. Settling on using the `gregset_t' and `fpregset_t'
	48	typedefs, providing them for the other systems, therefore solves
	49	the puzzle. */
	50
	51	#ifdef HAVE_MACHINE_REG_H
	52	#ifdef HAVE_STRUCT_REG
	53	typedef struct reg gregset_t;
	54	typedef struct fpreg fpregset_t;
	55	#else
	56	typedef struct regs gregset_t;
	57	typedef struct fp_status fpregset_t;
	58	#endif
	59	#endif
	60
	61	/* Second, we need to remap the BSD ptrace(2) requests to their SunOS
	62	equivalents. GNU/Linux already follows SunOS here. */
	63
	64	#ifndef PTRACE_GETREGS
	65	#define PTRACE_GETREGS PT_GETREGS
	66	#endif
	67
	68	#ifndef PTRACE_SETREGS
	69	#define PTRACE_SETREGS PT_SETREGS
	70	#endif
	71
	72	#ifndef PTRACE_GETFPREGS
	73	#define PTRACE_GETFPREGS PT_GETFPREGS
	74	#endif
	75
	76	#ifndef PTRACE_SETFPREGS
	77	#define PTRACE_SETFPREGS PT_SETFPREGS
	78	#endif
	79
	80	static PTRACE_TYPE_RET
	81	gdb_ptrace (PTRACE_TYPE_ARG1 request, ptid_t ptid, PTRACE_TYPE_ARG3 addr)
	82	{
	83	#ifdef __NetBSD__
	84	/* Support for NetBSD threads: unlike other ptrace implementations in this
	85	file, NetBSD requires that we pass both the pid and lwp. */
	86	return ptrace (request, ptid.pid (), addr, ptid.lwp ());
	87	#else
	88	pid_t pid = get_ptrace_pid (ptid);
	89	return ptrace (request, pid, addr, 0);
	90	#endif
	91	}
	92
	93	/* Register set description. */
	94	const struct sparc_gregmap *sparc_gregmap;
	95	const struct sparc_fpregmap *sparc_fpregmap;
	96	void (sparc_supply_gregset) (const struct sparc_gregmap ,
	97	struct regcache , int , const void );
	98	void (sparc_collect_gregset) (const struct sparc_gregmap ,
	99	const struct regcache , int, void );
	100	void (sparc_supply_fpregset) (const struct sparc_fpregmap ,
	101	struct regcache , int , const void );
	102	void (sparc_collect_fpregset) (const struct sparc_fpregmap ,
	103	const struct regcache , int , void );
	104	int (sparc_gregset_supplies_p) (struct gdbarch , int);
	105	int (sparc_fpregset_supplies_p) (struct gdbarch , int);
	106
	107	/* Determine whether `gregset_t' contains register REGNUM. */
	108
	109	int
	110	sparc32_gregset_supplies_p (struct gdbarch *gdbarch, int regnum)
	111	{
	112	/* Integer registers. */
	113	if ((regnum >= SPARC_G1_REGNUM && regnum <= SPARC_G7_REGNUM)
	114	\|\| (regnum >= SPARC_O0_REGNUM && regnum <= SPARC_O7_REGNUM)
	115	\|\| (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_L7_REGNUM)
	116	\|\| (regnum >= SPARC_I0_REGNUM && regnum <= SPARC_I7_REGNUM))
	117	return 1;
	118
	119	/* Control registers. */
	120	if (regnum == SPARC32_PC_REGNUM
	121	\|\| regnum == SPARC32_NPC_REGNUM
	122	\|\| regnum == SPARC32_PSR_REGNUM
	123	\|\| regnum == SPARC32_Y_REGNUM)
	124	return 1;
	125
	126	return 0;
	127	}
	128
	129	/* Determine whether `fpregset_t' contains register REGNUM. */
	130
	131	int
	132	sparc32_fpregset_supplies_p (struct gdbarch *gdbarch, int regnum)
	133	{
	134	/* Floating-point registers. */
	135	if (regnum >= SPARC_F0_REGNUM && regnum <= SPARC_F31_REGNUM)
	136	return 1;
	137
	138	/* Control registers. */
	139	if (regnum == SPARC32_FSR_REGNUM)
	140	return 1;
	141
	142	return 0;
	143	}
	144
	145	/* Fetch register REGNUM from the inferior. If REGNUM is -1, do this
	146	for all registers (including the floating-point registers). */
	147
	148	void
	149	sparc_fetch_inferior_registers (process_stratum_target *proc_target,
	150	regcache *regcache, int regnum)
	151	{
	152	struct gdbarch *gdbarch = regcache->arch ();
	153	ptid_t ptid = regcache->ptid ();
	154
	155	if (regnum == SPARC_G0_REGNUM)
	156	{
	157	regcache->raw_supply_zeroed (SPARC_G0_REGNUM);
	158	return;
	159	}
	160
	161	if (regnum == -1 \|\| sparc_gregset_supplies_p (gdbarch, regnum))
	162	{
	163	gregset_t regs;
	164
	165	if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	166	perror_with_name (_("Couldn't get registers"));
	167
	168	/* Deep down, sparc_supply_rwindow reads memory, so needs the global
	169	thread context to be set. */
	170	scoped_restore restore_inferior_ptid
	171	= make_scoped_restore (&inferior_ptid, ptid);
	172
	173	sparc_supply_gregset (sparc_gregmap, regcache, -1, &regs);
	174	if (regnum != -1)
	175	return;
	176	}
	177
	178	if (regnum == -1 \|\| sparc_fpregset_supplies_p (gdbarch, regnum))
	179	{
	180	fpregset_t fpregs;
	181
	182	if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
	183	perror_with_name (_("Couldn't get floating point status"));
	184
	185	sparc_supply_fpregset (sparc_fpregmap, regcache, -1, &fpregs);
	186	}
	187	}
	188
	189	void
	190	sparc_store_inferior_registers (process_stratum_target *proc_target,
	191	regcache *regcache, int regnum)
	192	{
	193	struct gdbarch *gdbarch = regcache->arch ();
	194	ptid_t ptid = regcache->ptid ();
	195
	196	if (regnum == -1 \|\| sparc_gregset_supplies_p (gdbarch, regnum))
	197	{
	198	gregset_t regs;
	199
	200	if (gdb_ptrace (PTRACE_GETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	201	perror_with_name (_("Couldn't get registers"));
	202
	203	sparc_collect_gregset (sparc_gregmap, regcache, regnum, &regs);
	204
	205	if (gdb_ptrace (PTRACE_SETREGS, ptid, (PTRACE_TYPE_ARG3) &regs) == -1)
	206	perror_with_name (_("Couldn't write registers"));
	207
	208	/* Deal with the stack regs. */
	209	if (regnum == -1 \|\| regnum == SPARC_SP_REGNUM
	210	\|\| (regnum >= SPARC_L0_REGNUM && regnum <= SPARC_I7_REGNUM))
	211	{
	212	ULONGEST sp;
	213
	214	regcache_cooked_read_unsigned (regcache, SPARC_SP_REGNUM, &sp);
	215
	216	/* Deep down, sparc_collect_rwindow writes memory, so needs the global
	217	thread context to be set. */
	218	scoped_restore restore_inferior_ptid
	219	= make_scoped_restore (&inferior_ptid, ptid);
	220
	221	sparc_collect_rwindow (regcache, sp, regnum);
	222	}
	223
	224	if (regnum != -1)
	225	return;
	226	}
	227
	228	if (regnum == -1 \|\| sparc_fpregset_supplies_p (gdbarch, regnum))
	229	{
	230	fpregset_t fpregs, saved_fpregs;
	231
	232	if (gdb_ptrace (PTRACE_GETFPREGS, ptid, (PTRACE_TYPE_ARG3) &fpregs) == -1)
	233	perror_with_name (_("Couldn't get floating-point registers"));
	234
	235	memcpy (&saved_fpregs, &fpregs, sizeof (fpregs));
	236	sparc_collect_fpregset (sparc_fpregmap, regcache, regnum, &fpregs);
	237
	238	/* Writing the floating-point registers will fail on NetBSD with
	239	EINVAL if the inferior process doesn't have an FPU state
	240	(i.e. if it didn't use the FPU yet). Therefore we don't try
	241	to write the registers if nothing changed. */
	242	if (memcmp (&saved_fpregs, &fpregs, sizeof (fpregs)) != 0)
	243	{
	244	if (gdb_ptrace (PTRACE_SETFPREGS, ptid,
	245	(PTRACE_TYPE_ARG3) &fpregs) == -1)
	246	perror_with_name (_("Couldn't write floating-point registers"));
	247	}
	248
	249	if (regnum != -1)
	250	return;
	251	}
	252	}
	253
	254	\f
	255	/* Implement the to_xfer_partial target_ops method for
	256	TARGET_OBJECT_WCOOKIE. Fetch StackGhost Per-Process XOR cookie. */
	257
	258	enum target_xfer_status
	259	sparc_xfer_wcookie (enum target_object object,
	260	const char annex, gdb_byte readbuf,
	261	const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
	262	ULONGEST *xfered_len)
	263	{
	264	unsigned long wcookie = 0;
	265	char buf = (char )&wcookie;
	266
	267	gdb_assert (object == TARGET_OBJECT_WCOOKIE);
	268	gdb_assert (readbuf && writebuf == NULL);
	269
	270	if (offset == sizeof (unsigned long))
	271	return TARGET_XFER_EOF; /* Signal EOF. */
	272	if (offset > sizeof (unsigned long))
	273	return TARGET_XFER_E_IO;
	274
	275	#ifdef PT_WCOOKIE
	276	/* If PT_WCOOKIE is defined (by <sys/ptrace.h>), assume we're
	277	running on an OpenBSD release that uses StackGhost (3.1 or
	278	later). Since release 3.6, OpenBSD uses a fully randomized
	279	cookie. */
	280	{
	281	int pid = inferior_ptid.pid ();
	282
	283	/* Sanity check. The proper type for a cookie is register_t, but
	284	we can't assume that this type exists on all systems supported
	285	by the code in this file. */
	286	gdb_assert (sizeof (wcookie) == sizeof (register_t));
	287
	288	/* Fetch the cookie. */
	289	if (ptrace (PT_WCOOKIE, pid, (PTRACE_TYPE_ARG3) &wcookie, 0) == -1)
	290	{
	291	if (errno != EINVAL)
	292	perror_with_name (_("Couldn't get StackGhost cookie"));
	293
	294	/* Although PT_WCOOKIE is defined on OpenBSD 3.1 and later,
	295	the request wasn't implemented until after OpenBSD 3.4. If
	296	the kernel doesn't support the PT_WCOOKIE request, assume
	297	we're running on a kernel that uses non-randomized cookies. */
	298	wcookie = 0x3;
	299	}
	300	}
	301	#endif /* PT_WCOOKIE */
	302
	303	if (len > sizeof (unsigned long) - offset)
	304	len = sizeof (unsigned long) - offset;
	305
	306	memcpy (readbuf, buf + offset, len);
	307	*xfered_len = (ULONGEST) len;
	308	return TARGET_XFER_OK;
	309	}
	310	\f
	311
	312	INIT_GDB_FILE (sparc_nat)
	313	{
	314	/* Default to using SunOS 4 register sets. */
	315	if (sparc_gregmap == NULL)
	316	sparc_gregmap = &sparc32_sunos4_gregmap;
	317	if (sparc_fpregmap == NULL)
	318	sparc_fpregmap = &sparc32_sunos4_fpregmap;
	319	if (sparc_supply_gregset == NULL)
	320	sparc_supply_gregset = sparc32_supply_gregset;
	321	if (sparc_collect_gregset == NULL)
	322	sparc_collect_gregset = sparc32_collect_gregset;
	323	if (sparc_supply_fpregset == NULL)
	324	sparc_supply_fpregset = sparc32_supply_fpregset;
	325	if (sparc_collect_fpregset == NULL)
	326	sparc_collect_fpregset = sparc32_collect_fpregset;
	327	if (sparc_gregset_supplies_p == NULL)
	328	sparc_gregset_supplies_p = sparc32_gregset_supplies_p;
	329	if (sparc_fpregset_supplies_p == NULL)
	330	sparc_fpregset_supplies_p = sparc32_fpregset_supplies_p;
	331	}