gdb/ppcnbsd-tdep.c

/* Target-dependent code for NetBSD/powerpc.

   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
   Free Software Foundation, Inc.

   Contributed by Wasabi Systems, 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 "defs.h"
#include "gdbtypes.h"
#include "osabi.h"
#include "regcache.h"
#include "regset.h"
#include "trad-frame.h"
#include "tramp-frame.h"

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

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

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

/* Core file support.  */

/* NetBSD/powerpc register sets.  */

struct regset ppcnbsd_gregset =
{
  &ppcnbsd_reg_offsets,
  ppc_supply_gregset
};

struct regset ppcnbsd_fpregset =
{
  &ppcnbsd_reg_offsets,
  ppc_supply_fpregset
};

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

static const struct regset *
ppcnbsd_regset_from_core_section (struct gdbarch *gdbarch,
				  const char *sect_name, size_t sect_size)
{
  if (strcmp (sect_name, ".reg") == 0 && sect_size >= 148)
    return &ppcnbsd_gregset;

  if (strcmp (sect_name, ".reg2") == 0 && sect_size >= 264)
    return &ppcnbsd_fpregset;

  return NULL;
}


/* NetBSD is confused.  It appears that 1.5 was using the correct SVR4
   convention but, 1.6 switched to the below broken convention.  For
   the moment use the broken convention.  Ulgh!.  */

static enum return_value_convention
ppcnbsd_return_value (struct gdbarch *gdbarch, struct type *func_type,
		      struct type *valtype, struct regcache *regcache,
		      gdb_byte *readbuf, const gdb_byte *writebuf)
{
#if 0
  if ((TYPE_CODE (valtype) == TYPE_CODE_STRUCT
       || TYPE_CODE (valtype) == TYPE_CODE_UNION)
      && !((TYPE_LENGTH (valtype) == 16 || TYPE_LENGTH (valtype) == 8)
	    && TYPE_VECTOR (valtype))
      && !(TYPE_LENGTH (valtype) == 1
	   || TYPE_LENGTH (valtype) == 2
	   || TYPE_LENGTH (valtype) == 4
	   || TYPE_LENGTH (valtype) == 8))
    return RETURN_VALUE_STRUCT_CONVENTION;
  else
#endif
    return ppc_sysv_abi_broken_return_value (gdbarch, func_type, valtype,
					     regcache, readbuf, writebuf);
}


/* Signal trampolines.  */

static const struct tramp_frame ppcnbsd2_sigtramp;

static void
ppcnbsd_sigtramp_cache_init (const struct tramp_frame *self,
			     struct frame_info *this_frame,
			     struct trad_frame_cache *this_cache,
			     CORE_ADDR func)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  CORE_ADDR addr, base;
  int i;

  base = get_frame_register_unsigned (this_frame,
				      gdbarch_sp_regnum (gdbarch));
  if (self == &ppcnbsd2_sigtramp)
    addr = base + 0x10 + 2 * tdep->wordsize;
  else
    addr = base + 0x18 + 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 (this_cache, regnum, addr);
    }
  trad_frame_set_reg_addr (this_cache, tdep->ppc_lr_regnum, addr);
  addr += tdep->wordsize;
  trad_frame_set_reg_addr (this_cache, tdep->ppc_cr_regnum, addr);
  addr += tdep->wordsize;
  trad_frame_set_reg_addr (this_cache, tdep->ppc_xer_regnum, addr);
  addr += tdep->wordsize;
  trad_frame_set_reg_addr (this_cache, tdep->ppc_ctr_regnum, addr);
  addr += tdep->wordsize;
  trad_frame_set_reg_addr (this_cache, gdbarch_pc_regnum (gdbarch),
			   addr); /* SRR0? */
  addr += tdep->wordsize;

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

static const struct tramp_frame ppcnbsd_sigtramp =
{
  SIGTRAMP_FRAME,
  4,
  {
    { 0x3821fff0, -1 },		/* add r1,r1,-16 */
    { 0x4e800021, -1 },		/* blrl */
    { 0x38610018, -1 },		/* addi r3,r1,24 */
    { 0x38000127, -1 },		/* li r0,295 */
    { 0x44000002, -1 },		/* sc */
    { 0x38000001, -1 },		/* li r0,1 */
    { 0x44000002, -1 },		/* sc */
    { TRAMP_SENTINEL_INSN, -1 }
  },
  ppcnbsd_sigtramp_cache_init
};

/* NetBSD 2.0 introduced a slightly different signal trampoline.  */

static const struct tramp_frame ppcnbsd2_sigtramp =
{
  SIGTRAMP_FRAME,
  4,
  {
    { 0x3821fff0, -1 },		/* add r1,r1,-16 */
    { 0x4e800021, -1 },		/* blrl */
    { 0x38610010, -1 },		/* addi r3,r1,16 */
    { 0x38000127, -1 },		/* li r0,295 */
    { 0x44000002, -1 },		/* sc */
    { 0x38000001, -1 },		/* li r0,1 */
    { 0x44000002, -1 },		/* sc */
    { TRAMP_SENTINEL_INSN, -1 }
  },
  ppcnbsd_sigtramp_cache_init
};


static void
ppcnbsd_init_abi (struct gdbarch_info info,
                  struct gdbarch *gdbarch)
{
  /* For NetBSD, this is an on again, off again thing.  Some systems
     do use the broken struct convention, and some don't.  */
  set_gdbarch_return_value (gdbarch, ppcnbsd_return_value);

  /* NetBSD 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, ppcnbsd_regset_from_core_section);

  tramp_frame_prepend_unwinder (gdbarch, &ppcnbsd_sigtramp);
  tramp_frame_prepend_unwinder (gdbarch, &ppcnbsd2_sigtramp);
}


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

void
_initialize_ppcnbsd_tdep (void)
{
  gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_NETBSD_ELF,
			  ppcnbsd_init_abi);

  /* Avoid initializing the register offsets again if they were
     already initailized by ppcnbsd-nat.c.  */
  if (ppcnbsd_reg_offsets.pc_offset == 0)
    {
      /* General-purpose registers.  */
      ppcnbsd_reg_offsets.r0_offset = 0;
      ppcnbsd_reg_offsets.gpr_size = 4;
      ppcnbsd_reg_offsets.xr_size = 4;
      ppcnbsd_reg_offsets.lr_offset = 128;
      ppcnbsd_reg_offsets.cr_offset = 132;
      ppcnbsd_reg_offsets.xer_offset = 136;
      ppcnbsd_reg_offsets.ctr_offset = 140;
      ppcnbsd_reg_offsets.pc_offset = 144;
      ppcnbsd_reg_offsets.ps_offset = -1;
      ppcnbsd_reg_offsets.mq_offset = -1;

      /* Floating-point registers.  */
      ppcnbsd_reg_offsets.f0_offset = 0;
      ppcnbsd_reg_offsets.fpscr_offset = 256;
      ppcnbsd_reg_offsets.fpscr_size = 4;

      /* AltiVec registers.  */
      ppcnbsd_reg_offsets.vr0_offset = 0;
      ppcnbsd_reg_offsets.vrsave_offset = 512;
      ppcnbsd_reg_offsets.vscr_offset = 524;
    }
}