xref: /src/external/gpl3/gdb/dist/bfd/elf32-m68hc12.c

/* Motorola 68HC12-specific support for 32-bit ELF
   Copyright 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007
   Free Software Foundation, Inc.
   Contributed by Stephane Carrez (stcarrez (at) nerim.fr)
   (Heavily copied from the D10V port by Martin Hunt (hunt (at) cygnus.com))

   This file is part of BFD, the Binary File Descriptor library.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include "bfd.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "elf32-m68hc1x.h"
#include "elf/m68hc11.h"
#include "opcode/m68hc11.h"

/* Relocation functions.  */
static reloc_howto_type *bfd_elf32_bfd_reloc_type_lookup
  (bfd *, bfd_reloc_code_real_type);
static void m68hc11_info_to_howto_rel
  (bfd *, arelent *, Elf_Internal_Rela *);

/* Trampoline generation.  */
static bfd_boolean m68hc12_elf_size_one_stub
  (struct bfd_hash_entry *gen_entry, void *in_arg);
static bfd_boolean m68hc12_elf_build_one_stub
  (struct bfd_hash_entry *gen_entry, void *in_arg);
static struct bfd_link_hash_table* m68hc12_elf_bfd_link_hash_table_create
  (bfd*);

static bfd_boolean m68hc12_elf_set_mach_from_flags PARAMS ((bfd *));

/* Use REL instead of RELA to save space */
#define USE_REL	1

/* The 68HC12 microcontroler has a memory bank switching system
   with a 16Kb window in the 64Kb address space.  The extended memory
   is mapped in the 16Kb window (at 0x8000).  The page register controls
   which 16Kb bank is mapped.  The call/rtc instructions take care of
   bank switching in function calls/returns.

   For GNU Binutils to work, we consider there is a physical memory
   at 0..0x0ffff and a kind of virtual memory above that.  Symbols
   in virtual memory have their addresses treated in a special way
   when disassembling and when linking.

   For the linker to work properly, we must always relocate the virtual
   memory as if it is mapped at 0x8000.  When a 16-bit relocation is
   made in the virtual memory, we check that it does not cross the
   memory bank where it is used.  This would involve a page change
   which would be wrong.  The 24-bit relocation is for that and it
   treats the address as a physical address + page number.


					Banked
					Address Space
                                        |               |       Page n
					+---------------+ 0x1010000
                                        |               |
                                        | jsr _foo      |
                                        | ..            |       Page 3
                                        | _foo:         |
					+---------------+ 0x100C000
					|	        |
                                        | call _bar     |
					| ..	        |	Page 2
					| _bar:	        |
					+---------------+ 0x1008000
				/------>|	        |
				|	| call _foo     |	Page 1
				|	|       	|
				|	+---------------+ 0x1004000
      Physical			|	|	        |
      Address Space		|	|	        |	Page 0
				|	|	        |
    +-----------+ 0x00FFFF	|	+---------------+ 0x1000000
    |		|		|
    | call _foo	|		|
    |		|		|
    +-----------+ 0x00BFFF -+---/
    |		|           |
    |		|	    |
    |		| 16K	    |
    |		|	    |
    +-----------+ 0x008000 -+
    |		|
    |		|
    =		=
    |		|
    |		|
    +-----------+ 0000


   The 'call _foo' must be relocated with page 3 and 16-bit address
   mapped at 0x8000.

   The 3-bit and 16-bit PC rel relocation is only used by 68HC12.  */
static reloc_howto_type elf_m68hc11_howto_table[] = {
  /* This reloc does nothing.  */
  HOWTO (R_M68HC11_NONE,	/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_NONE",	/* name */
	 FALSE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 8 bit absolute relocation */
  HOWTO (R_M68HC11_8,		/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_8",		/* name */
	 FALSE,			/* partial_inplace */
	 0x00ff,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 8 bit absolute relocation (upper address) */
  HOWTO (R_M68HC11_HI8,		/* type */
	 8,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_HI8",	/* name */
	 FALSE,			/* partial_inplace */
	 0x00ff,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 8 bit absolute relocation (upper address) */
  HOWTO (R_M68HC11_LO8,		/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_LO8",	/* name */
	 FALSE,			/* partial_inplace */
	 0x00ff,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 8 bit PC-rel relocation */
  HOWTO (R_M68HC11_PCREL_8,	/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 TRUE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_PCREL_8",	/* name */
	 FALSE,			/* partial_inplace */
	 0x00ff,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 TRUE),                 /* pcrel_offset */

  /* A 16 bit absolute relocation */
  HOWTO (R_M68HC11_16,		/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont /*bitfield */ ,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_16",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 32 bit absolute relocation.  This one is never used for the
     code relocation.  It's used by gas for -gstabs generation.  */
  HOWTO (R_M68HC11_32,		/* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 32,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_32",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffffffff,		/* src_mask */
	 0xffffffff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 3 bit absolute relocation */
  HOWTO (R_M68HC11_3B,		/* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 3,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_4B",	/* name */
	 FALSE,			/* partial_inplace */
	 0x003,			/* src_mask */
	 0x003,			/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 16 bit PC-rel relocation */
  HOWTO (R_M68HC11_PCREL_16,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 TRUE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 bfd_elf_generic_reloc,	/* special_function */
	 "R_M68HC12_PCREL_16",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 TRUE),                 /* pcrel_offset */

  /* GNU extension to record C++ vtable hierarchy */
  HOWTO (R_M68HC11_GNU_VTINHERIT,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 NULL,			/* special_function */
	 "R_M68HC11_GNU_VTINHERIT",	/* name */
	 FALSE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* GNU extension to record C++ vtable member usage */
  HOWTO (R_M68HC11_GNU_VTENTRY,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 _bfd_elf_rel_vtable_reloc_fn,	/* special_function */
	 "R_M68HC11_GNU_VTENTRY",	/* name */
	 FALSE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 24 bit relocation */
  HOWTO (R_M68HC11_24,	        /* type */
	 0,			/* rightshift */
	 2,			/* size (0 = byte, 1 = short, 2 = long) */
	 24,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 m68hc11_elf_special_reloc,	/* special_function */
	 "R_M68HC12_24",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffffff,		/* src_mask */
	 0xffffff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A 16-bit low relocation */
  HOWTO (R_M68HC11_LO16,        /* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 16,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 m68hc11_elf_special_reloc,/* special_function */
	 "R_M68HC12_LO16",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  /* A page relocation */
  HOWTO (R_M68HC11_PAGE,        /* type */
	 0,			/* rightshift */
	 0,			/* size (0 = byte, 1 = short, 2 = long) */
	 8,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 m68hc11_elf_special_reloc,/* special_function */
	 "R_M68HC12_PAGE",	/* name */
	 FALSE,			/* partial_inplace */
	 0x00ff,		/* src_mask */
	 0x00ff,		/* dst_mask */
	 FALSE),		/* pcrel_offset */

  EMPTY_HOWTO (14),
  EMPTY_HOWTO (15),
  EMPTY_HOWTO (16),
  EMPTY_HOWTO (17),
  EMPTY_HOWTO (18),
  EMPTY_HOWTO (19),

  /* Mark beginning of a jump instruction (any form).  */
  HOWTO (R_M68HC11_RL_JUMP,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 m68hc11_elf_ignore_reloc,	/* special_function */
	 "R_M68HC12_RL_JUMP",	/* name */
	 TRUE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 TRUE),                 /* pcrel_offset */

  /* Mark beginning of Gcc relaxation group instruction.  */
  HOWTO (R_M68HC11_RL_GROUP,	/* type */
	 0,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 0,			/* bitsize */
	 FALSE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont,	/* complain_on_overflow */
	 m68hc11_elf_ignore_reloc,	/* special_function */
	 "R_M68HC12_RL_GROUP",	/* name */
	 TRUE,			/* partial_inplace */
	 0,			/* src_mask */
	 0,			/* dst_mask */
	 TRUE),                 /* pcrel_offset */
};

/* Map BFD reloc types to M68HC11 ELF reloc types.  */

struct m68hc11_reloc_map
{
  bfd_reloc_code_real_type bfd_reloc_val;
  unsigned char elf_reloc_val;
};

static const struct m68hc11_reloc_map m68hc11_reloc_map[] = {
  {BFD_RELOC_NONE, R_M68HC11_NONE,},
  {BFD_RELOC_8, R_M68HC11_8},
  {BFD_RELOC_M68HC11_HI8, R_M68HC11_HI8},
  {BFD_RELOC_M68HC11_LO8, R_M68HC11_LO8},
  {BFD_RELOC_8_PCREL, R_M68HC11_PCREL_8},
  {BFD_RELOC_16_PCREL, R_M68HC11_PCREL_16},
  {BFD_RELOC_16, R_M68HC11_16},
  {BFD_RELOC_32, R_M68HC11_32},
  {BFD_RELOC_M68HC11_3B, R_M68HC11_3B},

  {BFD_RELOC_VTABLE_INHERIT, R_M68HC11_GNU_VTINHERIT},
  {BFD_RELOC_VTABLE_ENTRY, R_M68HC11_GNU_VTENTRY},

  {BFD_RELOC_M68HC11_LO16, R_M68HC11_LO16},
  {BFD_RELOC_M68HC11_PAGE, R_M68HC11_PAGE},
  {BFD_RELOC_M68HC11_24, R_M68HC11_24},

  {BFD_RELOC_M68HC11_RL_JUMP, R_M68HC11_RL_JUMP},
  {BFD_RELOC_M68HC11_RL_GROUP, R_M68HC11_RL_GROUP},
};

static reloc_howto_type *
bfd_elf32_bfd_reloc_type_lookup (bfd *abfd ATTRIBUTE_UNUSED,
                                 bfd_reloc_code_real_type code)
{
  unsigned int i;

  for (i = 0;
       i < sizeof (m68hc11_reloc_map) / sizeof (struct m68hc11_reloc_map);
       i++)
    {
      if (m68hc11_reloc_map[i].bfd_reloc_val == code)
	return &elf_m68hc11_howto_table[m68hc11_reloc_map[i].elf_reloc_val];
    }

  return NULL;
}

static reloc_howto_type *
bfd_elf32_bfd_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
				 const char *r_name)
{
  unsigned int i;

  for (i = 0;
       i < (sizeof (elf_m68hc11_howto_table)
	    / sizeof (elf_m68hc11_howto_table[0]));
       i++)
    if (elf_m68hc11_howto_table[i].name != NULL
	&& strcasecmp (elf_m68hc11_howto_table[i].name, r_name) == 0)
      return &elf_m68hc11_howto_table[i];

  return NULL;
}

/* Set the howto pointer for an M68HC11 ELF reloc.  */

static void
m68hc11_info_to_howto_rel (bfd *abfd ATTRIBUTE_UNUSED,
                           arelent *cache_ptr, Elf_Internal_Rela *dst)
{
  unsigned int r_type;

  r_type = ELF32_R_TYPE (dst->r_info);
  BFD_ASSERT (r_type < (unsigned int) R_M68HC11_max);
  cache_ptr->howto = &elf_m68hc11_howto_table[r_type];
}


/* Far trampoline generation.  */

/* Build a 68HC12 trampoline stub.  */
static bfd_boolean
m68hc12_elf_build_one_stub (struct bfd_hash_entry *gen_entry, void *in_arg)
{
  struct elf32_m68hc11_stub_hash_entry *stub_entry;
  struct bfd_link_info *info;
  struct m68hc11_elf_link_hash_table *htab;
  asection *stub_sec;
  bfd *stub_bfd;
  bfd_byte *loc;
  bfd_vma sym_value, phys_page, phys_addr;

  /* Massage our args to the form they really have.  */
  stub_entry = (struct elf32_m68hc11_stub_hash_entry *) gen_entry;
  info = (struct bfd_link_info *) in_arg;

  htab = m68hc11_elf_hash_table (info);

  stub_sec = stub_entry->stub_sec;

  /* Make a note of the offset within the stubs for this entry.  */
  stub_entry->stub_offset = stub_sec->size;
  stub_sec->size += 7;
  loc = stub_sec->contents + stub_entry->stub_offset;

  stub_bfd = stub_sec->owner;

  /* Create the trampoline call stub:

     ldy #%addr(symbol)
     call %page(symbol), __trampoline

  */
  sym_value = (stub_entry->target_value
               + stub_entry->target_section->output_offset
               + stub_entry->target_section->output_section->vma);
  phys_addr = m68hc11_phys_addr (&htab->pinfo, sym_value);
  phys_page = m68hc11_phys_page (&htab->pinfo, sym_value);

  /* ldy #%page(sym) */
  bfd_put_8 (stub_bfd, 0xCD, loc);
  bfd_put_16 (stub_bfd, phys_addr, loc + 1);
  loc += 3;

  /* call %page(sym), __trampoline  */
  bfd_put_8 (stub_bfd, 0x4a, loc);
  bfd_put_16 (stub_bfd, htab->pinfo.trampoline_addr, loc + 1);
  bfd_put_8 (stub_bfd, phys_page, loc + 3);

  return TRUE;
}

/* As above, but don't actually build the stub.  Just bump offset so
   we know stub section sizes.  */

static bfd_boolean
m68hc12_elf_size_one_stub (struct bfd_hash_entry *gen_entry,
                           void *in_arg ATTRIBUTE_UNUSED)
{
  struct elf32_m68hc11_stub_hash_entry *stub_entry;

  /* Massage our args to the form they really have.  */
  stub_entry = (struct elf32_m68hc11_stub_hash_entry *) gen_entry;

  stub_entry->stub_sec->size += 7;
  return TRUE;
}

/* Create a 68HC12 ELF linker hash table.  */

static struct bfd_link_hash_table *
m68hc12_elf_bfd_link_hash_table_create (bfd *abfd)
{
  struct m68hc11_elf_link_hash_table *ret;

  ret = m68hc11_elf_hash_table_create (abfd);
  if (ret == (struct m68hc11_elf_link_hash_table *) NULL)
    return NULL;

  ret->size_one_stub = m68hc12_elf_size_one_stub;
  ret->build_one_stub = m68hc12_elf_build_one_stub;

  return &ret->root.root;
}

static bfd_boolean
m68hc12_elf_set_mach_from_flags (bfd *abfd)
{
  flagword flags = elf_elfheader (abfd)->e_flags;

  switch (flags & EF_M68HC11_MACH_MASK)
    {
    case EF_M68HC12_MACH:
      bfd_default_set_arch_mach (abfd, bfd_arch_m68hc12, bfd_mach_m6812);
      break;
    case EF_M68HCS12_MACH:
      bfd_default_set_arch_mach (abfd, bfd_arch_m68hc12, bfd_mach_m6812s);
      break;
    case EF_M68HC11_GENERIC:
      bfd_default_set_arch_mach (abfd, bfd_arch_m68hc12,
                                 bfd_mach_m6812_default);
      break;
    default:
      return FALSE;
    }
  return TRUE;
}

/* Specific sections:
   - The .page0 is a data section that is mapped in [0x0000..0x00FF].
     Page0 accesses are faster on the M68HC12.
   - The .vectors is the section that represents the interrupt
     vectors.  */
static const struct bfd_elf_special_section elf32_m68hc12_special_sections[] =
{
  { STRING_COMMA_LEN (".eeprom"),   0, SHT_PROGBITS, SHF_ALLOC + SHF_WRITE },
  { STRING_COMMA_LEN (".page0"),    0, SHT_PROGBITS, SHF_ALLOC + SHF_WRITE },
  { STRING_COMMA_LEN (".softregs"), 0, SHT_NOBITS,   SHF_ALLOC + SHF_WRITE },
  { STRING_COMMA_LEN (".vectors"),  0, SHT_PROGBITS, SHF_ALLOC },
  { NULL,                       0,  0, 0,            0 }
};

#define ELF_ARCH		bfd_arch_m68hc12
#define ELF_TARGET_ID		M68HC11_ELF_DATA
#define ELF_MACHINE_CODE	EM_68HC12
#define ELF_MAXPAGESIZE		0x1000

#define TARGET_BIG_SYM          bfd_elf32_m68hc12_vec
#define TARGET_BIG_NAME		"elf32-m68hc12"

#define elf_info_to_howto	0
#define elf_info_to_howto_rel	m68hc11_info_to_howto_rel
#define elf_backend_check_relocs     elf32_m68hc11_check_relocs
#define elf_backend_relocate_section elf32_m68hc11_relocate_section
#define elf_backend_object_p		m68hc12_elf_set_mach_from_flags
#define elf_backend_final_write_processing	0
#define elf_backend_can_gc_sections		1
#define elf_backend_special_sections elf32_m68hc12_special_sections
#define elf_backend_post_process_headers     elf32_m68hc11_post_process_headers
#define elf_backend_add_symbol_hook  elf32_m68hc11_add_symbol_hook

#define bfd_elf32_bfd_link_hash_table_create \
                                m68hc12_elf_bfd_link_hash_table_create
#define bfd_elf32_bfd_link_hash_table_free \
				m68hc11_elf_bfd_link_hash_table_free
#define bfd_elf32_bfd_merge_private_bfd_data \
					_bfd_m68hc11_elf_merge_private_bfd_data
#define bfd_elf32_bfd_set_private_flags	_bfd_m68hc11_elf_set_private_flags
#define bfd_elf32_bfd_print_private_bfd_data \
					_bfd_m68hc11_elf_print_private_bfd_data

#include "elf32-target.h"