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/* Target-dependent code for Xilinx MicroBlaze.

   Copyright 2009, 2010 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 "defs.h"

#include "frame.h"

#include "inferior.h"

#include "symtab.h"

#include "target.h"

#include "gdbcore.h"

#include "gdbcmd.h"

#include "symfile.h"

#include "objfiles.h"

#include "regcache.h"

#include "value.h"

#include "osabi.h"

#include "regset.h"

#include "solib-svr4.h"

#include "microblaze-tdep.h"

#include "trad-frame.h"

#include "frame-unwind.h"

#include "tramp-frame.h"

static int

microblaze_linux_memory_remove_breakpoint (struct gdbarch *gdbarch,

                                           struct bp_target_info *bp_tgt)

{

  CORE_ADDR addr = bp_tgt->placed_address;

  const gdb_byte *bp;

  int val;

  int bplen;

  gdb_byte old_contents[BREAKPOINT_MAX];

  /* Determine appropriate breakpoint contents and size for this address.  */

  bp = gdbarch_breakpoint_from_pc (gdbarch, &addr, &bplen);

  if (bp == NULL)

    error (_("Software breakpoints not implemented for this target."));

  val = target_read_memory (addr, old_contents, bplen);

  /* If our breakpoint is no longer at the address, this means that the

     program modified the code on us, so it is wrong to put back the

     old value.  */

  if (val == 0 && memcmp (bp, old_contents, bplen) == 0)

    val = target_write_memory (addr, bp_tgt->shadow_contents, bplen);

  return val;

}

static void

microblaze_linux_sigtramp_cache (struct frame_info *next_frame,

                                 struct trad_frame_cache *this_cache,

                                 CORE_ADDR func, LONGEST offset,

                                 int bias)

{

  CORE_ADDR base;

  CORE_ADDR gpregs;

  int regnum;

  struct gdbarch *gdbarch = get_frame_arch (next_frame);

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  base = frame_unwind_register_unsigned (next_frame, MICROBLAZE_SP_REGNUM);

  if (bias > 0 && get_frame_address_in_block (next_frame) != func)

    /* See below, some signal trampolines increment the stack as their

       first instruction, need to compensate for that.  */

    base -= bias;

  /* Find the address of the register buffer.  */

  gpregs = base + offset;

  /* Registers saved on stack.  */

  for (regnum = 0; regnum < MICROBLAZE_BTR_REGNUM; regnum++)

    trad_frame_set_reg_addr (this_cache, regnum,

                             gpregs + regnum * MICROBLAZE_REGISTER_SIZE);

  trad_frame_set_id (this_cache, frame_id_build (base, func));

}

static void

microblaze_linux_sighandler_cache_init (const struct tramp_frame *self,

                                        struct frame_info *next_frame,

                                        struct trad_frame_cache *this_cache,

                                        CORE_ADDR func)

{

  microblaze_linux_sigtramp_cache (next_frame, this_cache, func,

                                   + 24 /* Offset to .reg.  */,

                                   0);

}

static struct tramp_frame microblaze_linux_sighandler_tramp_frame =

{

  SIGTRAMP_FRAME,

  4,

  {

    { 0x31800077, -1 }, /* addik R12,R0,119.  */

    { 0xb9cc0008, -1 }, /* brki R14,8.  */

    { TRAMP_SENTINEL_INSN },

  },

  microblaze_linux_sighandler_cache_init

};

static void

microblaze_linux_init_abi (struct gdbarch_info info,

                           struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  set_gdbarch_memory_remove_breakpoint (gdbarch,

                                        microblaze_linux_memory_remove_breakpoint);

  /* Shared library handling.  */

  set_solib_svr4_fetch_link_map_offsets (gdbarch,

                                         svr4_ilp32_fetch_link_map_offsets);

  /* Trampolines.  */

  tramp_frame_prepend_unwinder (gdbarch,

                                &microblaze_linux_sighandler_tramp_frame);

}

void

_initialize_microblaze_linux_tdep (void)

{

  gdbarch_register_osabi (bfd_arch_microblaze, 0, GDB_OSABI_LINUX,

                          microblaze_linux_init_abi);

}