gdb-6.6/gdb/ppcobsd-tdep.c - toolchain/gdb.git - Git at Google

 /* Target-dependent code for OpenBSD/powerpc.

    Copyright (C) 2004, 2005, 2006 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 2 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, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.  */

 #include "defs.h"
 #include "arch-utils.h"
 #include "floatformat.h"
 #include "frame.h"
 #include "frame-unwind.h"
 #include "osabi.h"
 #include "regcache.h"
 #include "regset.h"
 #include "symtab.h"
 #include "trad-frame.h"

 #include "gdb_assert.h"
 #include "gdb_string.h"

 #include "ppc-tdep.h"
 #include "ppcobsd-tdep.h"
 #include "solib-svr4.h"

 /* Register offsets from <machine/reg.h>.  */
 struct ppc_reg_offsets ppcobsd_reg_offsets;
 struct ppc_reg_offsets ppcobsd_fpreg_offsets;


 /* Core file support.  */

 /* Supply register REGNUM in the general-purpose register set REGSET
    from the buffer specified by GREGS and LEN to register cache
    REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

 void
 ppcobsd_supply_gregset (const struct regset *regset,
 			struct regcache *regcache, int regnum,
 			const void *gregs, size_t len)
 {
   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
      point registers.  Traditionally, GDB's register set has still
      listed the floating point registers for such machines, so this
      code is harmless.  However, the new E500 port actually omits the
      floating point registers entirely from the register set --- they
      don't even have register numbers assigned to them.

      It's not clear to me how best to update this code, so this assert
      will alert the first person to encounter the OpenBSD/E500
      combination to the problem.  */
   gdb_assert (ppc_floating_point_unit_p (current_gdbarch));

   ppc_supply_gregset (regset, regcache, regnum, gregs, len);
   ppc_supply_fpregset (regset, regcache, regnum, gregs, len);
 }

 /* Collect register REGNUM in the general-purpose register set
    REGSET. from register cache REGCACHE into the buffer specified by
    GREGS and LEN.  If REGNUM is -1, do this for all registers in
    REGSET.  */

 void
 ppcobsd_collect_gregset (const struct regset *regset,
 			 const struct regcache *regcache, int regnum,
 			 void *gregs, size_t len)
 {
   /* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
      point registers.  Traditionally, GDB's register set has still
      listed the floating point registers for such machines, so this
      code is harmless.  However, the new E500 port actually omits the
      floating point registers entirely from the register set --- they
      don't even have register numbers assigned to them.

      It's not clear to me how best to update this code, so this assert
      will alert the first person to encounter the OpenBSD/E500
      combination to the problem.  */
   gdb_assert (ppc_floating_point_unit_p (current_gdbarch));

   ppc_collect_gregset (regset, regcache, regnum, gregs, len);
   ppc_collect_fpregset (regset, regcache, regnum, gregs, len);
 }

 /* OpenBSD/powerpc register set.  */

 struct regset ppcobsd_gregset =
 {
   &ppcobsd_reg_offsets,
   ppcobsd_supply_gregset
 };

 struct regset ppcobsd_fpregset =
 {
   &ppcobsd_fpreg_offsets,
   ppc_supply_fpregset
 };

 /* Return the appropriate register set for the core section identified
    by SECT_NAME and SECT_SIZE.  */

 static const struct regset *
 ppcobsd_regset_from_core_section (struct gdbarch *gdbarch,
 				  const char *sect_name, size_t sect_size)
 {
   if (strcmp (sect_name, ".reg") == 0 && sect_size >= 412)
     return &ppcobsd_gregset;

   return NULL;
 }


 /* Signal trampolines.  */

 /* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
    in virtual memory.  The randomness makes it somewhat tricky to
    detect it, but fortunately we can rely on the fact that the start
    of the sigtramp routine is page-aligned.  We recognize the
    trampoline by looking for the code that invokes the sigreturn
    system call.  The offset where we can find that code varies from
    release to release.

    By the way, the mapping mentioned above is read-only, so you cannot
    place a breakpoint in the signal trampoline.  */

 /* Default page size.  */
 static const int ppcobsd_page_size = 4096;

 /* Offset for sigreturn(2).  */
 static const int ppcobsd_sigreturn_offset[] = {
   0x98,				/* OpenBSD 3.8 */
   0x0c,				/* OpenBSD 3.2 */
   -1
 };

 static int
 ppcobsd_sigtramp_p (struct frame_info *next_frame)
 {
   CORE_ADDR pc = frame_pc_unwind (next_frame);
   CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1));
   const int *offset;
   char *name;

   find_pc_partial_function (pc, &name, NULL, NULL);
   if (name)
     return 0;

   for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++)
     {
       gdb_byte buf[2 * PPC_INSN_SIZE];
       unsigned long insn;

       if (!safe_frame_unwind_memory (next_frame, start_pc + *offset,
 				     buf, sizeof buf))
 	continue;

       /* Check for "li r0,SYS_sigreturn".  */
       insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
       if (insn != 0x38000067)
 	continue;

       /* Check for "sc".  */
       insn = extract_unsigned_integer (buf + PPC_INSN_SIZE, PPC_INSN_SIZE);
       if (insn != 0x44000002)
 	continue;

       return 1;
     }

   return 0;
 }

 static struct trad_frame_cache *
 ppcobsd_sigtramp_frame_cache (struct frame_info *next_frame, void **this_cache)
 {
   struct gdbarch *gdbarch = get_frame_arch (next_frame);
   struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
   struct trad_frame_cache *cache;
   CORE_ADDR addr, base, func;
   gdb_byte buf[PPC_INSN_SIZE];
   unsigned long insn, sigcontext_offset;
   int i;

   if (*this_cache)
     return *this_cache;

   cache = trad_frame_cache_zalloc (next_frame);
   *this_cache = cache;

   func = frame_pc_unwind (next_frame);
   func &= ~(ppcobsd_page_size - 1);
   if (!safe_frame_unwind_memory (next_frame, func, buf, sizeof buf))
     return cache;

   /* Calculate the offset where we can find `struct sigcontext'.  We
      base our calculation on the amount of stack space reserved by the
      first instruction of the signal trampoline.  */
   insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
   sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8;

   base = frame_unwind_register_unsigned (next_frame, SP_REGNUM);
   addr = base + sigcontext_offset + 2 * tdep->wordsize;
   for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize)
     {
       int regnum = i + tdep->ppc_gp0_regnum;
       trad_frame_set_reg_addr (cache, regnum, addr);
     }
   trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr);
   addr += tdep->wordsize;
   trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr);
   addr += tdep->wordsize;
   trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr);
   addr += tdep->wordsize;
   trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr);
   addr += tdep->wordsize;
   trad_frame_set_reg_addr (cache, PC_REGNUM, addr); /* SRR0? */
   addr += tdep->wordsize;

   /* Construct the frame ID using the function start.  */
   trad_frame_set_id (cache, frame_id_build (base, func));

   return cache;
 }

 static void
 ppcobsd_sigtramp_frame_this_id (struct frame_info *next_frame,
 				void **this_cache, struct frame_id *this_id)
 {
   struct trad_frame_cache *cache =
     ppcobsd_sigtramp_frame_cache (next_frame, this_cache);

   trad_frame_get_id (cache, this_id);
 }

 static void
 ppcobsd_sigtramp_frame_prev_register (struct frame_info *next_frame,
 				      void **this_cache, int regnum,
 				      int *optimizedp, enum lval_type *lvalp,
 				      CORE_ADDR *addrp, int *realnump,
 				      gdb_byte *valuep)
 {
   struct trad_frame_cache *cache =
     ppcobsd_sigtramp_frame_cache (next_frame, this_cache);

   trad_frame_get_register (cache, next_frame, regnum,
 			   optimizedp, lvalp, addrp, realnump, valuep);
 }

 static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
   SIGTRAMP_FRAME,
   ppcobsd_sigtramp_frame_this_id,
   ppcobsd_sigtramp_frame_prev_register
 };

 static const struct frame_unwind *
 ppcobsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
 {
   if (ppcobsd_sigtramp_p (next_frame))
     return &ppcobsd_sigtramp_frame_unwind;

   return NULL;
 }


 static void
 ppcobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
 {
   /* OpenBSD doesn't support the 128-bit `long double' from the psABI.  */
   set_gdbarch_long_double_bit (gdbarch, 64);
   set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big);

   /* OpenBSD currently uses a broken GCC.  */
   set_gdbarch_return_value (gdbarch, ppc_sysv_abi_broken_return_value);

   /* OpenBSD uses SVR4-style shared libraries.  */
   set_solib_svr4_fetch_link_map_offsets
     (gdbarch, svr4_ilp32_fetch_link_map_offsets);

   set_gdbarch_regset_from_core_section
     (gdbarch, ppcobsd_regset_from_core_section);

   frame_unwind_append_sniffer (gdbarch, ppcobsd_sigtramp_frame_sniffer);
 }


 /* OpenBSD uses uses the traditional NetBSD core file format, even for
    ports that use ELF.  */
 #define GDB_OSABI_NETBSD_CORE GDB_OSABI_OPENBSD_ELF

 static enum gdb_osabi
 ppcobsd_core_osabi_sniffer (bfd *abfd)
 {
   if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
     return GDB_OSABI_NETBSD_CORE;

   return GDB_OSABI_UNKNOWN;
 }


 /* Provide a prototype to silence -Wmissing-prototypes.  */
 void _initialize_ppcobsd_tdep (void);

 void
 _initialize_ppcobsd_tdep (void)
 {
   /* BFD doesn't set a flavour for NetBSD style a.out core files.  */
   gdbarch_register_osabi_sniffer (bfd_arch_powerpc, bfd_target_unknown_flavour,
                                   ppcobsd_core_osabi_sniffer);

   gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_OPENBSD_ELF,
 			  ppcobsd_init_abi);
   gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_OPENBSD_ELF,
 			  ppcobsd_init_abi);

   /* Avoid initializing the register offsets again if they were
      already initailized by ppcobsd-nat.c.  */
   if (ppcobsd_reg_offsets.pc_offset == 0)
     {
       /* General-purpose registers.  */
       ppcobsd_reg_offsets.r0_offset = 0;
       ppcobsd_reg_offsets.pc_offset = 384;
       ppcobsd_reg_offsets.ps_offset = 388;
       ppcobsd_reg_offsets.cr_offset = 392;
       ppcobsd_reg_offsets.lr_offset = 396;
       ppcobsd_reg_offsets.ctr_offset = 400;
       ppcobsd_reg_offsets.xer_offset = 404;
       ppcobsd_reg_offsets.mq_offset = 408;

       /* Floating-point registers.  */
       ppcobsd_reg_offsets.f0_offset = 128;
       ppcobsd_reg_offsets.fpscr_offset = -1;

       /* AltiVec registers.  */
       ppcobsd_reg_offsets.vr0_offset = 0;
       ppcobsd_reg_offsets.vscr_offset = 512;
       ppcobsd_reg_offsets.vrsave_offset = 520;
     }

   if (ppcobsd_fpreg_offsets.fpscr_offset == 0)
     {
       /* Floating-point registers.  */
       ppcobsd_reg_offsets.f0_offset = 0;
       ppcobsd_reg_offsets.fpscr_offset = 256;
     }
 }
	/* Target-dependent code for OpenBSD/powerpc.

	Copyright (C) 2004, 2005, 2006 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 2 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, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor,
	Boston, MA 02110-1301, USA. */

	#include "defs.h"
	#include "arch-utils.h"
	#include "floatformat.h"
	#include "frame.h"
	#include "frame-unwind.h"
	#include "osabi.h"
	#include "regcache.h"
	#include "regset.h"
	#include "symtab.h"
	#include "trad-frame.h"

	#include "gdb_assert.h"
	#include "gdb_string.h"

	#include "ppc-tdep.h"
	#include "ppcobsd-tdep.h"
	#include "solib-svr4.h"

	/* Register offsets from <machine/reg.h>. */
	struct ppc_reg_offsets ppcobsd_reg_offsets;
	struct ppc_reg_offsets ppcobsd_fpreg_offsets;


	/* Core file support. */

	/* Supply register REGNUM in the general-purpose register set REGSET
	from the buffer specified by GREGS and LEN to register cache
	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */

	void
	ppcobsd_supply_gregset (const struct regset *regset,
	struct regcache *regcache, int regnum,
	const void *gregs, size_t len)
	{
	/* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
	point registers. Traditionally, GDB's register set has still
	listed the floating point registers for such machines, so this
	code is harmless. However, the new E500 port actually omits the
	floating point registers entirely from the register set --- they
	don't even have register numbers assigned to them.

	It's not clear to me how best to update this code, so this assert
	will alert the first person to encounter the OpenBSD/E500
	combination to the problem. */
	gdb_assert (ppc_floating_point_unit_p (current_gdbarch));

	ppc_supply_gregset (regset, regcache, regnum, gregs, len);
	ppc_supply_fpregset (regset, regcache, regnum, gregs, len);
	}

	/* Collect register REGNUM in the general-purpose register set
	REGSET. from register cache REGCACHE into the buffer specified by
	GREGS and LEN. If REGNUM is -1, do this for all registers in
	REGSET. */

	void
	ppcobsd_collect_gregset (const struct regset *regset,
	const struct regcache *regcache, int regnum,
	void *gregs, size_t len)
	{
	/* FIXME: jimb/2004-05-05: Some PPC variants don't have floating
	point registers. Traditionally, GDB's register set has still
	listed the floating point registers for such machines, so this
	code is harmless. However, the new E500 port actually omits the
	floating point registers entirely from the register set --- they
	don't even have register numbers assigned to them.

	It's not clear to me how best to update this code, so this assert
	will alert the first person to encounter the OpenBSD/E500
	combination to the problem. */
	gdb_assert (ppc_floating_point_unit_p (current_gdbarch));

	ppc_collect_gregset (regset, regcache, regnum, gregs, len);
	ppc_collect_fpregset (regset, regcache, regnum, gregs, len);
	}

	/* OpenBSD/powerpc register set. */

	struct regset ppcobsd_gregset =
	{
	&ppcobsd_reg_offsets,
	ppcobsd_supply_gregset
	};

	struct regset ppcobsd_fpregset =
	{
	&ppcobsd_fpreg_offsets,
	ppc_supply_fpregset
	};

	/* Return the appropriate register set for the core section identified
	by SECT_NAME and SECT_SIZE. */

	static const struct regset *
	ppcobsd_regset_from_core_section (struct gdbarch *gdbarch,
	const char *sect_name, size_t sect_size)
	{
	if (strcmp (sect_name, ".reg") == 0 && sect_size >= 412)
	return &ppcobsd_gregset;

	return NULL;
	}


	/* Signal trampolines. */

	/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page
	in virtual memory. The randomness makes it somewhat tricky to
	detect it, but fortunately we can rely on the fact that the start
	of the sigtramp routine is page-aligned. We recognize the
	trampoline by looking for the code that invokes the sigreturn
	system call. The offset where we can find that code varies from
	release to release.

	By the way, the mapping mentioned above is read-only, so you cannot
	place a breakpoint in the signal trampoline. */

	/* Default page size. */
	static const int ppcobsd_page_size = 4096;

	/* Offset for sigreturn(2). */
	static const int ppcobsd_sigreturn_offset[] = {
	0x98, /* OpenBSD 3.8 */
	0x0c, /* OpenBSD 3.2 */
	-1
	};

	static int
	ppcobsd_sigtramp_p (struct frame_info *next_frame)
	{
	CORE_ADDR pc = frame_pc_unwind (next_frame);
	CORE_ADDR start_pc = (pc & ~(ppcobsd_page_size - 1));
	const int *offset;
	char *name;

	find_pc_partial_function (pc, &name, NULL, NULL);
	if (name)
	return 0;

	for (offset = ppcobsd_sigreturn_offset; *offset != -1; offset++)
	{
	gdb_byte buf[2 * PPC_INSN_SIZE];
	unsigned long insn;

	if (!safe_frame_unwind_memory (next_frame, start_pc + *offset,
	buf, sizeof buf))
	continue;

	/* Check for "li r0,SYS_sigreturn". */
	insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
	if (insn != 0x38000067)
	continue;

	/* Check for "sc". */
	insn = extract_unsigned_integer (buf + PPC_INSN_SIZE, PPC_INSN_SIZE);
	if (insn != 0x44000002)
	continue;

	return 1;
	}

	return 0;
	}

	static struct trad_frame_cache *
	ppcobsd_sigtramp_frame_cache (struct frame_info next_frame, void *this_cache)
	{
	struct gdbarch *gdbarch = get_frame_arch (next_frame);
	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	struct trad_frame_cache *cache;
	CORE_ADDR addr, base, func;
	gdb_byte buf[PPC_INSN_SIZE];
	unsigned long insn, sigcontext_offset;
	int i;

	if (*this_cache)
	return *this_cache;

	cache = trad_frame_cache_zalloc (next_frame);
	*this_cache = cache;

	func = frame_pc_unwind (next_frame);
	func &= ~(ppcobsd_page_size - 1);
	if (!safe_frame_unwind_memory (next_frame, func, buf, sizeof buf))
	return cache;

	/* Calculate the offset where we can find `struct sigcontext'. We
	base our calculation on the amount of stack space reserved by the
	first instruction of the signal trampoline. */
	insn = extract_unsigned_integer (buf, PPC_INSN_SIZE);
	sigcontext_offset = (0x10000 - (insn & 0x0000ffff)) + 8;

	base = frame_unwind_register_unsigned (next_frame, SP_REGNUM);
	addr = base + sigcontext_offset + 2 * tdep->wordsize;
	for (i = 0; i < ppc_num_gprs; i++, addr += tdep->wordsize)
	{
	int regnum = i + tdep->ppc_gp0_regnum;
	trad_frame_set_reg_addr (cache, regnum, addr);
	}
	trad_frame_set_reg_addr (cache, tdep->ppc_lr_regnum, addr);
	addr += tdep->wordsize;
	trad_frame_set_reg_addr (cache, tdep->ppc_cr_regnum, addr);
	addr += tdep->wordsize;
	trad_frame_set_reg_addr (cache, tdep->ppc_xer_regnum, addr);
	addr += tdep->wordsize;
	trad_frame_set_reg_addr (cache, tdep->ppc_ctr_regnum, addr);
	addr += tdep->wordsize;
	trad_frame_set_reg_addr (cache, PC_REGNUM, addr); /* SRR0? */
	addr += tdep->wordsize;

	/* Construct the frame ID using the function start. */
	trad_frame_set_id (cache, frame_id_build (base, func));

	return cache;
	}

	static void
	ppcobsd_sigtramp_frame_this_id (struct frame_info *next_frame,
	void *this_cache, struct frame_id this_id)
	{
	struct trad_frame_cache *cache =
	ppcobsd_sigtramp_frame_cache (next_frame, this_cache);

	trad_frame_get_id (cache, this_id);
	}

	static void
	ppcobsd_sigtramp_frame_prev_register (struct frame_info *next_frame,
	void **this_cache, int regnum,
	int optimizedp, enum lval_type lvalp,
	CORE_ADDR addrp, int realnump,
	gdb_byte *valuep)
	{
	struct trad_frame_cache *cache =
	ppcobsd_sigtramp_frame_cache (next_frame, this_cache);

	trad_frame_get_register (cache, next_frame, regnum,
	optimizedp, lvalp, addrp, realnump, valuep);
	}

	static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
	SIGTRAMP_FRAME,
	ppcobsd_sigtramp_frame_this_id,
	ppcobsd_sigtramp_frame_prev_register
	};

	static const struct frame_unwind *
	ppcobsd_sigtramp_frame_sniffer (struct frame_info *next_frame)
	{
	if (ppcobsd_sigtramp_p (next_frame))
	return &ppcobsd_sigtramp_frame_unwind;

	return NULL;
	}


	static void
	ppcobsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
	{
	/* OpenBSD doesn't support the 128-bit `long double' from the psABI. */
	set_gdbarch_long_double_bit (gdbarch, 64);
	set_gdbarch_long_double_format (gdbarch, &floatformat_ieee_double_big);

	/* OpenBSD currently uses a broken GCC. */
	set_gdbarch_return_value (gdbarch, ppc_sysv_abi_broken_return_value);

	/* OpenBSD uses SVR4-style shared libraries. */
	set_solib_svr4_fetch_link_map_offsets
	(gdbarch, svr4_ilp32_fetch_link_map_offsets);

	set_gdbarch_regset_from_core_section
	(gdbarch, ppcobsd_regset_from_core_section);

	frame_unwind_append_sniffer (gdbarch, ppcobsd_sigtramp_frame_sniffer);
	}


	/* OpenBSD uses uses the traditional NetBSD core file format, even for
	ports that use ELF. */
	#define GDB_OSABI_NETBSD_CORE GDB_OSABI_OPENBSD_ELF

	static enum gdb_osabi
	ppcobsd_core_osabi_sniffer (bfd *abfd)
	{
	if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
	return GDB_OSABI_NETBSD_CORE;

	return GDB_OSABI_UNKNOWN;
	}


	/* Provide a prototype to silence -Wmissing-prototypes. */
	void _initialize_ppcobsd_tdep (void);

	void
	_initialize_ppcobsd_tdep (void)
	{
	/* BFD doesn't set a flavour for NetBSD style a.out core files. */
	gdbarch_register_osabi_sniffer (bfd_arch_powerpc, bfd_target_unknown_flavour,
	ppcobsd_core_osabi_sniffer);

	gdbarch_register_osabi (bfd_arch_rs6000, 0, GDB_OSABI_OPENBSD_ELF,
	ppcobsd_init_abi);
	gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_OPENBSD_ELF,
	ppcobsd_init_abi);

	/* Avoid initializing the register offsets again if they were
	already initailized by ppcobsd-nat.c. */
	if (ppcobsd_reg_offsets.pc_offset == 0)
	{
	/* General-purpose registers. */
	ppcobsd_reg_offsets.r0_offset = 0;
	ppcobsd_reg_offsets.pc_offset = 384;
	ppcobsd_reg_offsets.ps_offset = 388;
	ppcobsd_reg_offsets.cr_offset = 392;
	ppcobsd_reg_offsets.lr_offset = 396;
	ppcobsd_reg_offsets.ctr_offset = 400;
	ppcobsd_reg_offsets.xer_offset = 404;
	ppcobsd_reg_offsets.mq_offset = 408;

	/* Floating-point registers. */
	ppcobsd_reg_offsets.f0_offset = 128;
	ppcobsd_reg_offsets.fpscr_offset = -1;

	/* AltiVec registers. */
	ppcobsd_reg_offsets.vr0_offset = 0;
	ppcobsd_reg_offsets.vscr_offset = 512;
	ppcobsd_reg_offsets.vrsave_offset = 520;
	}

	if (ppcobsd_fpreg_offsets.fpscr_offset == 0)
	{
	/* Floating-point registers. */
	ppcobsd_reg_offsets.f0_offset = 0;
	ppcobsd_reg_offsets.fpscr_offset = 256;
	}
	}