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/* Motorola m68k target-dependent support for GNU/Linux.

   Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007, 2008

   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 "gdbcore.h"

#include "doublest.h"

#include "floatformat.h"

#include "frame.h"

#include "target.h"

#include "gdb_string.h"

#include "gdbtypes.h"

#include "osabi.h"

#include "regcache.h"

#include "objfiles.h"

#include "symtab.h"

#include "m68k-tdep.h"

#include "trad-frame.h"

#include "frame-unwind.h"

#include "glibc-tdep.h"

#include "solib-svr4.h"

#include "auxv.h"

#include "observer.h"

#include "elf/common.h"

/* Offsets (in target ints) into jmp_buf.  */

#define M68K_LINUX_JB_ELEMENT_SIZE 4

#define M68K_LINUX_JB_PC 7

/* Check whether insn1 and insn2 are parts of a signal trampoline.  */

#define IS_SIGTRAMP(insn1, insn2)                                       \

  (/* addaw #20,sp; moveq #119,d0; trap #0 */                           \

   (insn1 == 0xdefc0014 && insn2 == 0x70774e40)                         \

   /* moveq #119,d0; trap #0 */                                         \

   || insn1 == 0x70774e40)

#define IS_RT_SIGTRAMP(insn1, insn2)                                    \

  (/* movel #173,d0; trap #0 */                                         \

   (insn1 == 0x203c0000 && insn2 == 0x00ad4e40)                         \

   /* moveq #82,d0; notb d0; trap #0 */                                 \

   || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))

/* Return non-zero if PC points into the signal trampoline.  For the

   sake of m68k_linux_get_sigtramp_info we also distinguish between

   non-RT and RT signal trampolines.  */

static int

m68k_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)

{

  CORE_ADDR sp;

  char buf[12];

  unsigned long insn0, insn1, insn2;

  if (read_memory_nobpt (pc - 4, buf, sizeof (buf)))

    return 0;

  insn1 = extract_unsigned_integer (buf + 4, 4);

  insn2 = extract_unsigned_integer (buf + 8, 4);

  if (IS_SIGTRAMP (insn1, insn2))

    return 1;

  if (IS_RT_SIGTRAMP (insn1, insn2))

    return 2;

  insn0 = extract_unsigned_integer (buf, 4);

  if (IS_SIGTRAMP (insn0, insn1))

    return 1;

  if (IS_RT_SIGTRAMP (insn0, insn1))

    return 2;

  insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);

  insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);

  if (IS_SIGTRAMP (insn0, insn1))

    return 1;

  if (IS_RT_SIGTRAMP (insn0, insn1))

    return 2;

  return 0;

}

/* From <asm/sigcontext.h>.  */

static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =

{

  2 * 4,                        /* %d0 */

  3 * 4,                        /* %d1 */

  -1,                           /* %d2 */

  -1,                           /* %d3 */

  -1,                           /* %d4 */

  -1,                           /* %d5 */

  -1,                           /* %d6 */

  -1,                           /* %d7 */

  4 * 4,                        /* %a0 */

  5 * 4,                        /* %a1 */

  -1,                           /* %a2 */

  -1,                           /* %a3 */

  -1,                           /* %a4 */

  -1,                           /* %a5 */

  -1,                           /* %fp */

  1 * 4,                        /* %sp */

  6 * 4,                        /* %sr */

  6 * 4 + 2,                    /* %pc */

  8 * 4,                        /* %fp0 */

  11 * 4,                       /* %fp1 */

  -1,                           /* %fp2 */

  -1,                           /* %fp3 */

  -1,                           /* %fp4 */

  -1,                           /* %fp5 */

  -1,                           /* %fp6 */

  -1,                           /* %fp7 */

  14 * 4,                       /* %fpcr */

  15 * 4,                       /* %fpsr */

  16 * 4                        /* %fpiaddr */

};

static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] =

{

  2 * 4,                        /* %d0 */

  3 * 4,                        /* %d1 */

  -1,                           /* %d2 */

  -1,                           /* %d3 */

  -1,                           /* %d4 */

  -1,                           /* %d5 */

  -1,                           /* %d6 */

  -1,                           /* %d7 */

  4 * 4,                        /* %a0 */

  5 * 4,                        /* %a1 */

  -1,                           /* %a2 */

  -1,                           /* %a3 */

  -1,                           /* %a4 */

  6 * 4,                        /* %a5 */

  -1,                           /* %fp */

  1 * 4,                        /* %sp */

  7 * 4,                        /* %sr */

  7 * 4 + 2,                    /* %pc */

  -1,                           /* %fp0 */

  -1,                           /* %fp1 */

  -1,                           /* %fp2 */

  -1,                           /* %fp3 */

  -1,                           /* %fp4 */

  -1,                           /* %fp5 */

  -1,                           /* %fp6 */

  -1,                           /* %fp7 */

  -1,                           /* %fpcr */

  -1,                           /* %fpsr */

  -1                            /* %fpiaddr */

};

/* From <asm/ucontext.h>.  */

static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =

{

  6 * 4,                        /* %d0 */

  7 * 4,                        /* %d1 */

  8 * 4,                        /* %d2 */

  9 * 4,                        /* %d3 */

  10 * 4,                       /* %d4 */

  11 * 4,                       /* %d5 */

  12 * 4,                       /* %d6 */

  13 * 4,                       /* %d7 */

  14 * 4,                       /* %a0 */

  15 * 4,                       /* %a1 */

  16 * 4,                       /* %a2 */

  17 * 4,                       /* %a3 */

  18 * 4,                       /* %a4 */

  19 * 4,                       /* %a5 */

  20 * 4,                       /* %fp */

  21 * 4,                       /* %sp */

  23 * 4,                       /* %sr */

  22 * 4,                       /* %pc */

  27 * 4,                       /* %fp0 */

  30 * 4,                       /* %fp1 */

  33 * 4,                       /* %fp2 */

  36 * 4,                       /* %fp3 */

  39 * 4,                       /* %fp4 */

  42 * 4,                       /* %fp5 */

  45 * 4,                       /* %fp6 */

  48 * 4,                       /* %fp7 */

  24 * 4,                       /* %fpcr */

  25 * 4,                       /* %fpsr */

  26 * 4                        /* %fpiaddr */

};

/* Get info about saved registers in sigtramp.  */

struct m68k_linux_sigtramp_info

{

  /* Address of sigcontext.  */

  CORE_ADDR sigcontext_addr;

  /* Offset of registers in `struct sigcontext'.  */

  int *sc_reg_offset;

};

/* Nonzero if running on uClinux.  */

static int target_is_uclinux;

static void

m68k_linux_inferior_created (struct target_ops *objfile, int from_tty)

{

  /* Record that we will need to re-evaluate whether we are running on a

     uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info).  */

  target_is_uclinux = -1;

}

static struct m68k_linux_sigtramp_info

m68k_linux_get_sigtramp_info (struct frame_info *next_frame)

{

  CORE_ADDR sp;

  char buf[4];

  struct m68k_linux_sigtramp_info info;

  if (target_is_uclinux == -1)

    {

      /* Determine whether we are running on a uClinux or normal GNU/Linux

         target so we can use the correct sigcontext layouts.  */

      CORE_ADDR dummy;

      target_is_uclinux

        = target_auxv_search (&current_target, AT_NULL, &dummy) > 0

          && target_auxv_search (&current_target, AT_PAGESZ, &dummy) == 0;

    }

  frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);

  sp = extract_unsigned_integer (buf, 4);

  /* Get sigcontext address, it is the third parameter on the stack.  */

  info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);

  if (m68k_linux_pc_in_sigtramp (frame_pc_unwind (next_frame), 0) == 2)

    info.sc_reg_offset = m68k_linux_ucontext_reg_offset;

  else

    info.sc_reg_offset

      = target_is_uclinux ? m68k_uclinux_sigcontext_reg_offset

                          : m68k_linux_sigcontext_reg_offset;

  return info;

}

/* Signal trampolines.  */

static struct trad_frame_cache *

m68k_linux_sigtramp_frame_cache (struct frame_info *next_frame,

                                 void **this_cache)

{

  struct frame_id this_id;

  struct trad_frame_cache *cache;

  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (next_frame));

  struct m68k_linux_sigtramp_info info;

  char buf[4];

  int i;

  if (*this_cache)

    return *this_cache;

  cache = trad_frame_cache_zalloc (next_frame);

  /* FIXME: cagney/2004-05-01: This is is long standing broken code.

     The frame ID's code address should be the start-address of the

     signal trampoline and not the current PC within that

     trampoline.  */

  frame_unwind_register (next_frame, M68K_SP_REGNUM, buf);

  /* See the end of m68k_push_dummy_call.  */

  this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8,

                            frame_pc_unwind (next_frame));

  trad_frame_set_id (cache, this_id);

  info = m68k_linux_get_sigtramp_info (next_frame);

  for (i = 0; i < M68K_NUM_REGS; i++)

    if (info.sc_reg_offset[i] != -1)

      trad_frame_set_reg_addr (cache, i,

                               info.sigcontext_addr + info.sc_reg_offset[i]);

  *this_cache = cache;

  return cache;

}

static void

m68k_linux_sigtramp_frame_this_id (struct frame_info *next_frame,

                                   void **this_cache,

                                   struct frame_id *this_id)

{

  struct trad_frame_cache *cache =

    m68k_linux_sigtramp_frame_cache (next_frame, this_cache);

  trad_frame_get_id (cache, this_id);

}

static void

m68k_linux_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)

{

  /* Make sure we've initialized the cache.  */

  struct trad_frame_cache *cache =

    m68k_linux_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 m68k_linux_sigtramp_frame_unwind =

{

  SIGTRAMP_FRAME,

  m68k_linux_sigtramp_frame_this_id,

  m68k_linux_sigtramp_frame_prev_register

};

static const struct frame_unwind *

m68k_linux_sigtramp_frame_sniffer (struct frame_info *next_frame)

{

  CORE_ADDR pc = frame_pc_unwind (next_frame);

  char *name;

  find_pc_partial_function (pc, &name, NULL, NULL);

  if (m68k_linux_pc_in_sigtramp (pc, name))

    return &m68k_linux_sigtramp_frame_unwind;

  return NULL;

}

static void

m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)

{

  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  tdep->jb_pc = M68K_LINUX_JB_PC;

  tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;

  /* GNU/Linux uses a calling convention that's similar to SVR4.  It

     returns integer values in %d0/%d1, pointer values in %a0 and

     floating values in %fp0, just like SVR4, but uses %a1 to pass the

     address to store a structure value.  It also returns small

     structures in registers instead of memory.  */

  m68k_svr4_init_abi (info, gdbarch);

  tdep->struct_value_regnum = M68K_A1_REGNUM;

  tdep->struct_return = reg_struct_return;

  set_gdbarch_decr_pc_after_break (gdbarch, 2);

  frame_unwind_append_sniffer (gdbarch, m68k_linux_sigtramp_frame_sniffer);

  /* Shared library handling.  */

  /* GNU/Linux uses SVR4-style shared libraries.  */

  set_solib_svr4_fetch_link_map_offsets (gdbarch,

                                         svr4_ilp32_fetch_link_map_offsets);

  /* GNU/Linux uses the dynamic linker included in the GNU C Library.  */

  set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);

  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);

  /* Enable TLS support.  */

  set_gdbarch_fetch_tls_load_module_address (gdbarch,

                                             svr4_fetch_objfile_link_map);

}

void

_initialize_m68k_linux_tdep (void)

{

  gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,

                          m68k_linux_init_abi);

  observer_attach_inferior_created (m68k_linux_inferior_created);

}