bfd/elf32-mt.c

/* Morpho Technologies MT specific support for 32-bit ELF
   Copyright (C) 2001-2023 Free Software Foundation, Inc.

   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 "libbfd.h"
#include "elf-bfd.h"
#include "elf/mt.h"

/* Prototypes.  */
static reloc_howto_type * mt_reloc_type_lookup
  (bfd *, bfd_reloc_code_real_type);

static bool mt_info_to_howto_rela
  (bfd *, arelent *, Elf_Internal_Rela *);

static bfd_reloc_status_type mt_elf_relocate_hi16
  (bfd *, Elf_Internal_Rela *, bfd_byte *, bfd_vma);

static bfd_reloc_status_type mt_final_link_relocate
  (reloc_howto_type *, bfd *, asection *, bfd_byte *,
   Elf_Internal_Rela *, bfd_vma);

static int mt_elf_relocate_section
  (bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
   Elf_Internal_Rela *, Elf_Internal_Sym *, asection **);

/* Relocation tables.  */
static reloc_howto_type mt_elf_howto_table [] =
{
  /* This reloc does nothing.  */
  HOWTO (R_MT_NONE,	      /* type */
	  0,			  /* rightshift */
	  0,			  /* size */
	  0,			  /* bitsize */
	  false,		  /* pc_relative */
	  0,			  /* bitpos */
	  complain_overflow_dont, /* complain_on_overflow */
	  bfd_elf_generic_reloc,  /* special_function */
	  "R_MT_NONE",		/* name */
	  false,		  /* partial_inplace */
	  0 ,			  /* src_mask */
	  0,			  /* dst_mask */
	  false),		  /* pcrel_offset */

  /* A 16 bit absolute relocation.  */
  HOWTO (R_MT_16,	      /* type */
	  0,			  /* rightshift */
	  4,			  /* size */
	  16,			  /* bitsize */
	  false,		  /* pc_relative */
	  0,			  /* bitpos */
	  complain_overflow_dont, /* complain_on_overflow */
	  bfd_elf_generic_reloc,  /* special_function */
	  "R_MT_16",		/* name */
	  false,		  /* partial_inplace */
	  0 ,			  /* src_mask */
	  0xffff,		  /* dst_mask */
	  false),		  /* pcrel_offset */

  /* A 32 bit absolute relocation.  */
  HOWTO (R_MT_32,	      /* type */
	  0,			  /* rightshift */
	  4,			  /* size */
	  32,			  /* bitsize */
	  false,		  /* pc_relative */
	  0,			  /* bitpos */
	  complain_overflow_dont, /* complain_on_overflow */
	  bfd_elf_generic_reloc,  /* special_function */
	  "R_MT_32",		/* name */
	  false,		  /* partial_inplace */
	  0 ,			  /* src_mask */
	  0xffffffff,		  /* dst_mask */
	  false),		  /* pcrel_offset */

  /* A 32 bit pc-relative relocation.  */
  HOWTO (R_MT_32_PCREL,	      /* type */
	  0,			  /* rightshift */
	  4,			  /* size */
	  32,			  /* bitsize */
	  true,			  /* pc_relative */
	  0,			  /* bitpos */
	  complain_overflow_dont, /* complain_on_overflow */
	  bfd_elf_generic_reloc,  /* special_function */
	  "R_MT_32_PCREL",    /* name */
	  false,		  /* partial_inplace */
	  0 ,			  /* src_mask */
	  0xffffffff,		  /* dst_mask */
	  true),		  /* pcrel_offset */

  /* A 16 bit pc-relative relocation.  */
  HOWTO (R_MT_PC16,	      /* type */
	  0,			  /* rightshift */
	  4,			  /* size */
	  16,			  /* bitsize */
	  true,			  /* pc_relative */
	  0,			  /* bitpos */
	  complain_overflow_signed, /* complain_on_overflow */
	  bfd_elf_generic_reloc,  /* special_function */
	  "R_MT_PC16",		/* name */
	  false,		  /* partial_inplace */
	  0,			  /* src_mask */
	  0xffff,		  /* dst_mask */
	  true),		  /* pcrel_offset */

  /* high 16 bits of symbol value.  */
  HOWTO (R_MT_HI16,	     /* type */
	 0,			/* rightshift */
	 4,			/* size */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 bfd_elf_generic_reloc, /* special_function */
	 "R_MT_HI16",	     /* name */
	 false,			 /* partial_inplace */
	 0xffff0000,		/* src_mask */
	 0xffff0000,		/* dst_mask */
	 false),		/* pcrel_offset */

  /* Low 16 bits of symbol value.  */
  HOWTO (R_MT_LO16,	     /* type */
	 0,			/* rightshift */
	 4,			/* size */
	 16,			/* bitsize */
	 false,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_dont, /* complain_on_overflow */
	 bfd_elf_generic_reloc, /* special_function */
	 "R_MT_LO16",	     /* name */
	 false,			 /* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 false),		/* pcrel_offset */
};

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

static reloc_howto_type *
mt_reloc_type_lookup
    (bfd *		      abfd ATTRIBUTE_UNUSED,
     bfd_reloc_code_real_type code)
{
  /* Note that the mt_elf_howto_table is indxed by the R_
     constants.  Thus, the order that the howto records appear in the
     table *must* match the order of the relocation types defined in
     include/elf/mt.h.  */

  switch (code)
    {
    case BFD_RELOC_NONE:
      return &mt_elf_howto_table[ (int) R_MT_NONE];
    case BFD_RELOC_16:
      return &mt_elf_howto_table[ (int) R_MT_16];
    case BFD_RELOC_32:
      return &mt_elf_howto_table[ (int) R_MT_32];
    case BFD_RELOC_32_PCREL:
      return &mt_elf_howto_table[ (int) R_MT_32_PCREL];
    case BFD_RELOC_16_PCREL:
      return &mt_elf_howto_table[ (int) R_MT_PC16];
    case BFD_RELOC_HI16:
      return &mt_elf_howto_table[ (int) R_MT_HI16];
    case BFD_RELOC_LO16:
      return &mt_elf_howto_table[ (int) R_MT_LO16];

    default:
      /* Pacify gcc -Wall.  */
      return NULL;
    }
  return NULL;
}

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

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

  return NULL;
}

bfd_reloc_status_type
mt_elf_relocate_hi16
    (bfd *		 input_bfd,
     Elf_Internal_Rela * relhi,
     bfd_byte *		 contents,
     bfd_vma		 value)
{
  bfd_vma insn;

  insn = bfd_get_32 (input_bfd, contents + relhi->r_offset);

  value += relhi->r_addend;
  value >>= 16;
  insn = ((insn & ~0xFFFF) | value);

  bfd_put_32 (input_bfd, insn, contents + relhi->r_offset);
  return bfd_reloc_ok;
}

/* XXX: The following code is the result of a cut&paste.  This unfortunate
   practice is very widespread in the various target back-end files.  */

/* Set the howto pointer for a MT ELF reloc.  */

static bool
mt_info_to_howto_rela (bfd *abfd,
		       arelent *cache_ptr,
		       Elf_Internal_Rela *dst)
{
  unsigned int r_type;

  r_type = ELF32_R_TYPE (dst->r_info);
  if (r_type >= (unsigned int) R_MT_max)
    {
      /* xgettext:c-format */
      _bfd_error_handler (_("%pB: unsupported relocation type %#x"),
			  abfd, r_type);
      bfd_set_error (bfd_error_bad_value);
      return false;
    }
  cache_ptr->howto = & mt_elf_howto_table [r_type];
  return true;
}

/* Perform a single relocation.  By default we use the standard BFD
   routines.  */

static bfd_reloc_status_type
mt_final_link_relocate
    (reloc_howto_type *	 howto,
     bfd *		 input_bfd,
     asection *		 input_section,
     bfd_byte *		 contents,
     Elf_Internal_Rela * rel,
     bfd_vma		 relocation)
{
  return _bfd_final_link_relocate (howto, input_bfd, input_section,
				   contents, rel->r_offset,
				   relocation, rel->r_addend);
}

/* Relocate a MT ELF section.
   There is some attempt to make this function usable for many architectures,
   both USE_REL and USE_RELA ['twould be nice if such a critter existed],
   if only to serve as a learning tool.

   The RELOCATE_SECTION function is called by the new ELF backend linker
   to handle the relocations for a section.

   The relocs are always passed as Rela structures; if the section
   actually uses Rel structures, the r_addend field will always be
   zero.

   This function is responsible for adjusting the section contents as
   necessary, and (if using Rela relocs and generating a relocatable
   output file) adjusting the reloc addend as necessary.

   This function does not have to worry about setting the reloc
   address or the reloc symbol index.

   LOCAL_SYMS is a pointer to the swapped in local symbols.

   LOCAL_SECTIONS is an array giving the section in the input file
   corresponding to the st_shndx field of each local symbol.

   The global hash table entry for the global symbols can be found
   via elf_sym_hashes (input_bfd).

   When generating relocatable output, this function must handle
   STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
   going to be the section symbol corresponding to the output
   section, which means that the addend must be adjusted
   accordingly.  */

static int
mt_elf_relocate_section
    (bfd *		     output_bfd ATTRIBUTE_UNUSED,
     struct bfd_link_info *  info,
     bfd *		     input_bfd,
     asection *		     input_section,
     bfd_byte *		     contents,
     Elf_Internal_Rela *     relocs,
     Elf_Internal_Sym *	     local_syms,
     asection **	     local_sections)
{
  Elf_Internal_Shdr *		symtab_hdr;
  struct elf_link_hash_entry ** sym_hashes;
  Elf_Internal_Rela *		rel;
  Elf_Internal_Rela *		relend;

  symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (input_bfd);
  relend     = relocs + input_section->reloc_count;

  for (rel = relocs; rel < relend; rel ++)
    {
      reloc_howto_type *	   howto;
      unsigned long		   r_symndx;
      Elf_Internal_Sym *	   sym;
      asection *		   sec;
      struct elf_link_hash_entry * h;
      bfd_vma			   relocation;
      bfd_reloc_status_type	   r;
      const char *		   name = NULL;
      int			   r_type;

      r_type = ELF32_R_TYPE (rel->r_info);

      r_symndx = ELF32_R_SYM (rel->r_info);

      howto  = mt_elf_howto_table + ELF32_R_TYPE (rel->r_info);
      h      = NULL;
      sym    = NULL;
      sec    = NULL;

      if (r_symndx < symtab_hdr->sh_info)
	{
	  sym = local_syms + r_symndx;
	  sec = local_sections [r_symndx];
	  relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);

	  name = bfd_elf_string_from_elf_section
	    (input_bfd, symtab_hdr->sh_link, sym->st_name);
	  name = name == NULL ? bfd_section_name (sec) : name;
	}
      else
	{
	  bool unresolved_reloc;
	  bool warned, ignored;

	  RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
				   r_symndx, symtab_hdr, sym_hashes,
				   h, sec, relocation,
				   unresolved_reloc, warned, ignored);

	  name = h->root.root.string;
	}

      if (sec != NULL && discarded_section (sec))
	RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
					 rel, 1, relend, howto, 0, contents);

      if (bfd_link_relocatable (info))
	continue;

      /* Finally, the sole MT-specific part.  */
      switch (r_type)
	{
	case R_MT_HI16:
	  r = mt_elf_relocate_hi16 (input_bfd, rel, contents, relocation);
	  break;
	default:
	  r = mt_final_link_relocate (howto, input_bfd, input_section,
					  contents, rel, relocation);
	  break;
	}


      if (r != bfd_reloc_ok)
	{
	  const char * msg = (const char *) NULL;

	  switch (r)
	    {
	    case bfd_reloc_overflow:
	      (*info->callbacks->reloc_overflow)
		(info, (h ? &h->root : NULL), name, howto->name, (bfd_vma) 0,
		 input_bfd, input_section, rel->r_offset);
	      break;

	    case bfd_reloc_undefined:
	      (*info->callbacks->undefined_symbol)
		(info, name, input_bfd, input_section, rel->r_offset, true);
	      break;

	    case bfd_reloc_outofrange:
	      msg = _("internal error: out of range error");
	      break;

	    case bfd_reloc_dangerous:
	      msg = _("internal error: dangerous relocation");
	      break;

	    default:
	      msg = _("internal error: unknown error");
	      break;
	    }

	  if (msg)
	    (*info->callbacks->warning) (info, msg, name, input_bfd,
					 input_section, rel->r_offset);
	}
    }

  return true;
}

/* Look through the relocs for a section during the first phase.
   Since we don't do .gots or .plts, we just need to consider the
   virtual table relocs for gc.  */

static bool
mt_elf_check_relocs (bfd *abfd,
		     struct bfd_link_info *info,
		     asection *sec,
		     const Elf_Internal_Rela *relocs)
{
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  const Elf_Internal_Rela *rel;
  const Elf_Internal_Rela *rel_end;

  if (bfd_link_relocatable (info))
    return true;

  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);

  rel_end = relocs + sec->reloc_count;
  for (rel = relocs; rel < rel_end; rel++)
    {
      struct elf_link_hash_entry *h;
      unsigned long r_symndx;

      r_symndx = ELF32_R_SYM (rel->r_info);
      if (r_symndx < symtab_hdr->sh_info)
	h = NULL;
      else
	{
	  h = sym_hashes[r_symndx - symtab_hdr->sh_info];
	  while (h->root.type == bfd_link_hash_indirect
		 || h->root.type == bfd_link_hash_warning)
	    h = (struct elf_link_hash_entry *) h->root.u.i.link;
	}
    }

  return true;
}

/* Return the MACH for an e_flags value.  */

static int
elf32_mt_machine (bfd *abfd)
{
  switch (elf_elfheader (abfd)->e_flags & EF_MT_CPU_MASK)
    {
    case EF_MT_CPU_MRISC:	return bfd_mach_ms1;
    case EF_MT_CPU_MRISC2:	return bfd_mach_mrisc2;
    case EF_MT_CPU_MS2:		return bfd_mach_ms2;
    }

  return bfd_mach_ms1;
}

static bool
mt_elf_object_p (bfd *abfd)
{
  bfd_default_set_arch_mach (abfd, bfd_arch_mt, elf32_mt_machine (abfd));

  return true;
}

/* Function to set the ELF flag bits.  */

static bool
mt_elf_set_private_flags (bfd *abfd, flagword flags)
{
  elf_elfheader (abfd)->e_flags = flags;
  elf_flags_init (abfd) = true;
  return true;
}

/* Merge backend specific data from an object file to the output
   object file when linking.  */

static bool
mt_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
{
  bfd *obfd = info->output_bfd;
  flagword old_flags, new_flags;
  bool ok = true;

  /* Check if we have the same endianness.  */
  if (!_bfd_generic_verify_endian_match (ibfd, info))
    return false;

  /* If they're not both mt, then merging is meaningless, so just
     don't do it.  */
  if (strcmp (ibfd->arch_info->arch_name, "mt") != 0)
    return true;
  if (strcmp (obfd->arch_info->arch_name, "mt") != 0)
    return true;

  new_flags = elf_elfheader (ibfd)->e_flags;
  old_flags = elf_elfheader (obfd)->e_flags;

#ifdef DEBUG
  _bfd_error_handler ("%pB: old_flags = 0x%.8x, new_flags = 0x%.8x, init = %s",
		      ibfd, old_flags, new_flags, elf_flags_init (obfd) ? "yes" : "no");
#endif

  if (!elf_flags_init (obfd))
    {
      old_flags = new_flags;
      elf_flags_init (obfd) = true;
    }
  else if ((new_flags & EF_MT_CPU_MASK) != (old_flags & EF_MT_CPU_MASK))
    {
      /* CPU has changed.  This is invalid, because MRISC, MRISC2 and
	 MS2 are not subsets of each other.   */
      ok = false;
    }

  if (ok)
    {
      obfd->arch_info = ibfd->arch_info;
      elf_elfheader (obfd)->e_flags = old_flags;
    }

  return ok;
}

static bool
mt_elf_print_private_bfd_data (bfd *abfd, void *ptr)
{
  FILE *file = (FILE *) ptr;
  flagword flags;

  BFD_ASSERT (abfd != NULL && ptr != NULL);

  /* Print normal ELF private data.  */
  _bfd_elf_print_private_bfd_data (abfd, ptr);

  flags = elf_elfheader (abfd)->e_flags;
  fprintf (file, _("private flags = 0x%lx:"), (unsigned long) flags);

  switch (flags & EF_MT_CPU_MASK)
    {
    default:
    case EF_MT_CPU_MRISC:   fprintf (file, " ms1-16-002");	break;
    case EF_MT_CPU_MRISC2:  fprintf (file, " ms1-16-003");	break;
    case EF_MT_CPU_MS2:     fprintf (file, " ms2");	break;
    }

  fputc ('\n', file);

  return true;
}


#define TARGET_BIG_SYM	 mt_elf32_vec
#define TARGET_BIG_NAME	 "elf32-mt"

#define ELF_ARCH	 bfd_arch_mt
#define ELF_MACHINE_CODE EM_MT
#define ELF_MAXPAGESIZE	 1 /* No pages on the MT.  */

#define elf_info_to_howto_rel			NULL
#define elf_info_to_howto			mt_info_to_howto_rela

#define elf_backend_relocate_section		mt_elf_relocate_section

#define bfd_elf32_bfd_reloc_type_lookup		mt_reloc_type_lookup
#define bfd_elf32_bfd_reloc_name_lookup	  mt_reloc_name_lookup

#define elf_backend_check_relocs		mt_elf_check_relocs
#define elf_backend_object_p			mt_elf_object_p
#define elf_backend_rela_normal			1

#define elf_backend_can_gc_sections		1

#define bfd_elf32_bfd_set_private_flags		mt_elf_set_private_flags
#define bfd_elf32_bfd_merge_private_bfd_data	mt_elf_merge_private_bfd_data
#define bfd_elf32_bfd_print_private_bfd_data	mt_elf_print_private_bfd_data

#include "elf32-target.h"