[deliverable/binutils-gdb.git] / gdb / m68klinux-tdep.c

/* 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"
\f
/* 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 THIS_FRAME corresponds to a 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 (struct frame_info *this_frame)
{
  CORE_ADDR sp;
  gdb_byte buf[12];
  unsigned long insn0, insn1, insn2;
  CORE_ADDR pc = get_frame_pc (this_frame);

  if (!safe_frame_unwind_memory (this_frame, 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 *this_frame)
{
  CORE_ADDR sp;
  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);
    }

  sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);

  /* 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 (this_frame) == 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 *this_frame,
				 void **this_cache)
{
  struct frame_id this_id;
  struct trad_frame_cache *cache;
  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
  struct m68k_linux_sigtramp_info info;
  gdb_byte buf[4];
  int i;

  if (*this_cache)
    return *this_cache;

  cache = trad_frame_cache_zalloc (this_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.  */
  get_frame_register (this_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,
			    get_frame_pc (this_frame));
  trad_frame_set_id (cache, this_id);

  info = m68k_linux_get_sigtramp_info (this_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 *this_frame,
				   void **this_cache,
				   struct frame_id *this_id)
{
  struct trad_frame_cache *cache =
    m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
  trad_frame_get_id (cache, this_id);
}

static struct value *
m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
					 void **this_cache,
					 int regnum)
{
  /* Make sure we've initialized the cache.  */
  struct trad_frame_cache *cache =
    m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
  return trad_frame_get_register (cache, this_frame, regnum);
}

static int
m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
				   struct frame_info *this_frame,
				   void **this_prologue_cache)
{
  return m68k_linux_pc_in_sigtramp (this_frame);
}

static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
{
  SIGTRAMP_FRAME,
  m68k_linux_sigtramp_frame_this_id,
  m68k_linux_sigtramp_frame_prev_register,
  NULL,
  m68k_linux_sigtramp_frame_sniffer
};

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_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);

  /* 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);
}
Commit	Line	Data
	1	/* Motorola m68k target-dependent support for GNU/Linux.
	2
	3	Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2007, 2008
	4	Free Software Foundation, Inc.
	5
	6	This file is part of GDB.
	7
	8	This program is free software; you can redistribute it and/or modify
	9	it under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 3 of the License, or
	11	(at your option) any later version.
	12
	13	This program is distributed in the hope that it will be useful,
	14	but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	GNU General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	20
	21	#include "defs.h"
	22	#include "gdbcore.h"
	23	#include "doublest.h"
	24	#include "floatformat.h"
	25	#include "frame.h"
	26	#include "target.h"
	27	#include "gdb_string.h"
	28	#include "gdbtypes.h"
	29	#include "osabi.h"
	30	#include "regcache.h"
	31	#include "objfiles.h"
	32	#include "symtab.h"
	33	#include "m68k-tdep.h"
	34	#include "trad-frame.h"
	35	#include "frame-unwind.h"
	36	#include "glibc-tdep.h"
	37	#include "solib-svr4.h"
	38	#include "auxv.h"
	39	#include "observer.h"
	40	#include "elf/common.h"
	41	\f
	42	/* Offsets (in target ints) into jmp_buf. */
	43
	44	#define M68K_LINUX_JB_ELEMENT_SIZE 4
	45	#define M68K_LINUX_JB_PC 7
	46
	47	/* Check whether insn1 and insn2 are parts of a signal trampoline. */
	48
	49	#define IS_SIGTRAMP(insn1, insn2) \
	50	(/* addaw #20,sp; moveq #119,d0; trap #0 */ \
	51	(insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
	52	/* moveq #119,d0; trap #0 */ \
	53	\|\| insn1 == 0x70774e40)
	54
	55	#define IS_RT_SIGTRAMP(insn1, insn2) \
	56	(/* movel #173,d0; trap #0 */ \
	57	(insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
	58	/* moveq #82,d0; notb d0; trap #0 */ \
	59	\|\| (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
	60
	61	/* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For
	62	the sake of m68k_linux_get_sigtramp_info we also distinguish between
	63	non-RT and RT signal trampolines. */
	64
	65	static int
	66	m68k_linux_pc_in_sigtramp (struct frame_info *this_frame)
	67	{
	68	CORE_ADDR sp;
	69	gdb_byte buf[12];
	70	unsigned long insn0, insn1, insn2;
	71	CORE_ADDR pc = get_frame_pc (this_frame);
	72
	73	if (!safe_frame_unwind_memory (this_frame, pc - 4, buf, sizeof (buf)))
	74	return 0;
	75	insn1 = extract_unsigned_integer (buf + 4, 4);
	76	insn2 = extract_unsigned_integer (buf + 8, 4);
	77	if (IS_SIGTRAMP (insn1, insn2))
	78	return 1;
	79	if (IS_RT_SIGTRAMP (insn1, insn2))
	80	return 2;
	81
	82	insn0 = extract_unsigned_integer (buf, 4);
	83	if (IS_SIGTRAMP (insn0, insn1))
	84	return 1;
	85	if (IS_RT_SIGTRAMP (insn0, insn1))
	86	return 2;
	87
	88	insn0 = ((insn0 << 16) & 0xffffffff) \| (insn1 >> 16);
	89	insn1 = ((insn1 << 16) & 0xffffffff) \| (insn2 >> 16);
	90	if (IS_SIGTRAMP (insn0, insn1))
	91	return 1;
	92	if (IS_RT_SIGTRAMP (insn0, insn1))
	93	return 2;
	94
	95	return 0;
	96	}
	97
	98	/* From <asm/sigcontext.h>. */
	99	static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
	100	{
	101	2 * 4, /* %d0 */
	102	3 * 4, /* %d1 */
	103	-1, /* %d2 */
	104	-1, /* %d3 */
	105	-1, /* %d4 */
	106	-1, /* %d5 */
	107	-1, /* %d6 */
	108	-1, /* %d7 */
	109	4 * 4, /* %a0 */
	110	5 * 4, /* %a1 */
	111	-1, /* %a2 */
	112	-1, /* %a3 */
	113	-1, /* %a4 */
	114	-1, /* %a5 */
	115	-1, /* %fp */
	116	1 * 4, /* %sp */
	117	6 * 4, /* %sr */
	118	6 * 4 + 2, /* %pc */
	119	8 * 4, /* %fp0 */
	120	11 * 4, /* %fp1 */
	121	-1, /* %fp2 */
	122	-1, /* %fp3 */
	123	-1, /* %fp4 */
	124	-1, /* %fp5 */
	125	-1, /* %fp6 */
	126	-1, /* %fp7 */
	127	14 * 4, /* %fpcr */
	128	15 * 4, /* %fpsr */
	129	16 * 4 /* %fpiaddr */
	130	};
	131
	132	static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] =
	133	{
	134	2 * 4, /* %d0 */
	135	3 * 4, /* %d1 */
	136	-1, /* %d2 */
	137	-1, /* %d3 */
	138	-1, /* %d4 */
	139	-1, /* %d5 */
	140	-1, /* %d6 */
	141	-1, /* %d7 */
	142	4 * 4, /* %a0 */
	143	5 * 4, /* %a1 */
	144	-1, /* %a2 */
	145	-1, /* %a3 */
	146	-1, /* %a4 */
	147	6 * 4, /* %a5 */
	148	-1, /* %fp */
	149	1 * 4, /* %sp */
	150	7 * 4, /* %sr */
	151	7 * 4 + 2, /* %pc */
	152	-1, /* %fp0 */
	153	-1, /* %fp1 */
	154	-1, /* %fp2 */
	155	-1, /* %fp3 */
	156	-1, /* %fp4 */
	157	-1, /* %fp5 */
	158	-1, /* %fp6 */
	159	-1, /* %fp7 */
	160	-1, /* %fpcr */
	161	-1, /* %fpsr */
	162	-1 /* %fpiaddr */
	163	};
	164
	165	/* From <asm/ucontext.h>. */
	166	static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
	167	{
	168	6 * 4, /* %d0 */
	169	7 * 4, /* %d1 */
	170	8 * 4, /* %d2 */
	171	9 * 4, /* %d3 */
	172	10 * 4, /* %d4 */
	173	11 * 4, /* %d5 */
	174	12 * 4, /* %d6 */
	175	13 * 4, /* %d7 */
	176	14 * 4, /* %a0 */
	177	15 * 4, /* %a1 */
	178	16 * 4, /* %a2 */
	179	17 * 4, /* %a3 */
	180	18 * 4, /* %a4 */
	181	19 * 4, /* %a5 */
	182	20 * 4, /* %fp */
	183	21 * 4, /* %sp */
	184	23 * 4, /* %sr */
	185	22 * 4, /* %pc */
	186	27 * 4, /* %fp0 */
	187	30 * 4, /* %fp1 */
	188	33 * 4, /* %fp2 */
	189	36 * 4, /* %fp3 */
	190	39 * 4, /* %fp4 */
	191	42 * 4, /* %fp5 */
	192	45 * 4, /* %fp6 */
	193	48 * 4, /* %fp7 */
	194	24 * 4, /* %fpcr */
	195	25 * 4, /* %fpsr */
	196	26 * 4 /* %fpiaddr */
	197	};
	198
	199
	200	/* Get info about saved registers in sigtramp. */
	201
	202	struct m68k_linux_sigtramp_info
	203	{
	204	/* Address of sigcontext. */
	205	CORE_ADDR sigcontext_addr;
	206
	207	/* Offset of registers in `struct sigcontext'. */
	208	int *sc_reg_offset;
	209	};
	210
	211	/* Nonzero if running on uClinux. */
	212	static int target_is_uclinux;
	213
	214	static void
	215	m68k_linux_inferior_created (struct target_ops *objfile, int from_tty)
	216	{
	217	/* Record that we will need to re-evaluate whether we are running on a
	218	uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
	219	target_is_uclinux = -1;
	220	}
	221
	222	static struct m68k_linux_sigtramp_info
	223	m68k_linux_get_sigtramp_info (struct frame_info *this_frame)
	224	{
	225	CORE_ADDR sp;
	226	struct m68k_linux_sigtramp_info info;
	227
	228	if (target_is_uclinux == -1)
	229	{
	230	/* Determine whether we are running on a uClinux or normal GNU/Linux
	231	target so we can use the correct sigcontext layouts. */
	232	CORE_ADDR dummy;
	233
	234	target_is_uclinux
	235	= (target_auxv_search (&current_target, AT_NULL, &dummy) > 0
	236	&& target_auxv_search (&current_target, AT_PAGESZ, &dummy) == 0);
	237	}
	238
	239	sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
	240
	241	/* Get sigcontext address, it is the third parameter on the stack. */
	242	info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4);
	243
	244	if (m68k_linux_pc_in_sigtramp (this_frame) == 2)
	245	info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
	246	else
	247	info.sc_reg_offset = (target_is_uclinux
	248	? m68k_uclinux_sigcontext_reg_offset
	249	: m68k_linux_sigcontext_reg_offset);
	250	return info;
	251	}
	252
	253	/* Signal trampolines. */
	254
	255	static struct trad_frame_cache *
	256	m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame,
	257	void **this_cache)
	258	{
	259	struct frame_id this_id;
	260	struct trad_frame_cache *cache;
	261	struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
	262	struct m68k_linux_sigtramp_info info;
	263	gdb_byte buf[4];
	264	int i;
	265
	266	if (*this_cache)
	267	return *this_cache;
	268
	269	cache = trad_frame_cache_zalloc (this_frame);
	270
	271	/* FIXME: cagney/2004-05-01: This is is long standing broken code.
	272	The frame ID's code address should be the start-address of the
	273	signal trampoline and not the current PC within that
	274	trampoline. */
	275	get_frame_register (this_frame, M68K_SP_REGNUM, buf);
	276	/* See the end of m68k_push_dummy_call. */
	277	this_id = frame_id_build (extract_unsigned_integer (buf, 4) - 4 + 8,
	278	get_frame_pc (this_frame));
	279	trad_frame_set_id (cache, this_id);
	280
	281	info = m68k_linux_get_sigtramp_info (this_frame);
	282
	283	for (i = 0; i < M68K_NUM_REGS; i++)
	284	if (info.sc_reg_offset[i] != -1)
	285	trad_frame_set_reg_addr (cache, i,
	286	info.sigcontext_addr + info.sc_reg_offset[i]);
	287
	288	*this_cache = cache;
	289	return cache;
	290	}
	291
	292	static void
	293	m68k_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
	294	void **this_cache,
	295	struct frame_id *this_id)
	296	{
	297	struct trad_frame_cache *cache =
	298	m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
	299	trad_frame_get_id (cache, this_id);
	300	}
	301
	302	static struct value *
	303	m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
	304	void **this_cache,
	305	int regnum)
	306	{
	307	/* Make sure we've initialized the cache. */
	308	struct trad_frame_cache *cache =
	309	m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
	310	return trad_frame_get_register (cache, this_frame, regnum);
	311	}
	312
	313	static int
	314	m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
	315	struct frame_info *this_frame,
	316	void **this_prologue_cache)
	317	{
	318	return m68k_linux_pc_in_sigtramp (this_frame);
	319	}
	320
	321	static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
	322	{
	323	SIGTRAMP_FRAME,
	324	m68k_linux_sigtramp_frame_this_id,
	325	m68k_linux_sigtramp_frame_prev_register,
	326	NULL,
	327	m68k_linux_sigtramp_frame_sniffer
	328	};
	329
	330	static void
	331	m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
	332	{
	333	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	334
	335	tdep->jb_pc = M68K_LINUX_JB_PC;
	336	tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
	337
	338	/* GNU/Linux uses a calling convention that's similar to SVR4. It
	339	returns integer values in %d0/%d1, pointer values in %a0 and
	340	floating values in %fp0, just like SVR4, but uses %a1 to pass the
	341	address to store a structure value. It also returns small
	342	structures in registers instead of memory. */
	343	m68k_svr4_init_abi (info, gdbarch);
	344	tdep->struct_value_regnum = M68K_A1_REGNUM;
	345	tdep->struct_return = reg_struct_return;
	346
	347	set_gdbarch_decr_pc_after_break (gdbarch, 2);
	348
	349	frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);
	350
	351	/* Shared library handling. */
	352
	353	/* GNU/Linux uses SVR4-style shared libraries. */
	354	set_solib_svr4_fetch_link_map_offsets (gdbarch,
	355	svr4_ilp32_fetch_link_map_offsets);
	356
	357	/* GNU/Linux uses the dynamic linker included in the GNU C Library. */
	358	set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
	359
	360	set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
	361
	362	/* Enable TLS support. */
	363	set_gdbarch_fetch_tls_load_module_address (gdbarch,
	364	svr4_fetch_objfile_link_map);
	365	}
	366
	367	void
	368	_initialize_m68k_linux_tdep (void)
	369	{
	370	gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
	371	m68k_linux_init_abi);
	372	observer_attach_inferior_created (m68k_linux_inferior_created);
	373	}