elf64-x86-64.c

基于4个mips核的noc设计

/* X86-64 specific support for 64-bit ELF
   Copyright 2000, 2001 Free Software Foundation, Inc.
   Contributed by Jan Hubicka <[e-mail]>.

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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "elf-bfd.h"

#include "elf/x86-64.h"

/* We use only the RELA entries.  */
#define USE_RELA

/* In case we're on a 32-bit machine, construct a 64-bit "-1" value.  */
#define MINUS_ONE (~ (bfd_vma) 0)

/* The relocation "howto" table.  Order of fields:
   type, size, bitsize, pc_relative, complain_on_overflow,
   special_function, name, partial_inplace, src_mask, dst_pack, pcrel_offset.  */
static reloc_howto_type x86_64_elf_howto_table[] =
{
  HOWTO(R_X86_64_NONE, 0, 0, 0, false, 0, complain_overflow_dont,
	bfd_elf_generic_reloc, "R_X86_64_NONE",	false, 0x00000000, 0x00000000,
	false),
  HOWTO(R_X86_64_64, 0, 4, 64, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_64", false, MINUS_ONE, MINUS_ONE,
	false),
  HOWTO(R_X86_64_PC32, 0, 4, 32, true, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_PC32", false, 0xffffffff, 0xffffffff,
	true),
  HOWTO(R_X86_64_GOT32, 0, 4, 32, false, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_GOT32", false, 0xffffffff, 0xffffffff,
	false),
  HOWTO(R_X86_64_PLT32, 0, 4, 32, true, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_PLT32", false, 0xffffffff, 0xffffffff,
	true),
  HOWTO(R_X86_64_COPY, 0, 4, 32, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_COPY", false, 0xffffffff, 0xffffffff,
	false),
  HOWTO(R_X86_64_GLOB_DAT, 0, 4, 64, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_GLOB_DAT", false, MINUS_ONE,
	MINUS_ONE, false),
  HOWTO(R_X86_64_JUMP_SLOT, 0, 4, 64, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_JUMP_SLOT", false, MINUS_ONE,
	MINUS_ONE, false),
  HOWTO(R_X86_64_RELATIVE, 0, 4, 64, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_RELATIVE", false, MINUS_ONE,
	MINUS_ONE, false),
  HOWTO(R_X86_64_GOTPCREL, 0, 4, 32, true,0 , complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_GOTPCREL", false, 0xffffffff,
	0xffffffff, true),
  HOWTO(R_X86_64_32, 0, 4, 32, false, 0, complain_overflow_unsigned,
	bfd_elf_generic_reloc, "R_X86_64_32", false, 0xffffffff, 0xffffffff,
	false),
  HOWTO(R_X86_64_32S, 0, 4, 32, false, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_32S", false, 0xffffffff, 0xffffffff,
	false),
  HOWTO(R_X86_64_16, 0, 1, 16, false, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_16", false, 0xffff, 0xffff, false),
  HOWTO(R_X86_64_PC16,0, 1, 16, true, 0, complain_overflow_bitfield,
	bfd_elf_generic_reloc, "R_X86_64_PC16", false, 0xffff, 0xffff, true),
  HOWTO(R_X86_64_8, 0, 0, 8, false, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_8", false, 0xff, 0xff, false),
  HOWTO(R_X86_64_PC8, 0, 0, 8, true, 0, complain_overflow_signed,
	bfd_elf_generic_reloc, "R_X86_64_PC8", false, 0xff, 0xff, true)
};

/* Map BFD relocs to the x86_64 elf relocs.  */
struct elf_reloc_map
{
  bfd_reloc_code_real_type bfd_reloc_val;
  unsigned char elf_reloc_val;
};

static CONST struct elf_reloc_map x86_64_reloc_map[] =
{
  { BFD_RELOC_NONE,		R_X86_64_NONE, },
  { BFD_RELOC_64,		R_X86_64_64,   },
  { BFD_RELOC_32_PCREL,		R_X86_64_PC32, },
  { BFD_RELOC_X86_64_GOT32,	R_X86_64_GOT32,},
  { BFD_RELOC_X86_64_PLT32,	R_X86_64_PLT32,},
  { BFD_RELOC_X86_64_COPY,	R_X86_64_COPY, },
  { BFD_RELOC_X86_64_GLOB_DAT,	R_X86_64_GLOB_DAT, },
  { BFD_RELOC_X86_64_JUMP_SLOT, R_X86_64_JUMP_SLOT, },
  { BFD_RELOC_X86_64_RELATIVE,	R_X86_64_RELATIVE, },
  { BFD_RELOC_X86_64_GOTPCREL,	R_X86_64_GOTPCREL, },
  { BFD_RELOC_32,		R_X86_64_32, },
  { BFD_RELOC_X86_64_32S,	R_X86_64_32S, },
  { BFD_RELOC_16,		R_X86_64_16, },
  { BFD_RELOC_16_PCREL,		R_X86_64_PC16, },
  { BFD_RELOC_8,		R_X86_64_8, },
  { BFD_RELOC_8_PCREL,		R_X86_64_PC8, },
};

static reloc_howto_type *elf64_x86_64_reloc_type_lookup
  PARAMS ((bfd *, bfd_reloc_code_real_type));
static void elf64_x86_64_info_to_howto
  PARAMS ((bfd *, arelent *, Elf64_Internal_Rela *));
static struct bfd_link_hash_table *elf64_x86_64_link_hash_table_create
  PARAMS ((bfd *));

static struct bfd_hash_entry *elf64_x86_64_link_hash_newfunc
  PARAMS ((struct bfd_hash_entry *, struct bfd_hash_table *, const char *));
static boolean elf64_x86_64_adjust_dynamic_symbol
  PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));

static boolean elf64_x86_64_size_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));
static boolean elf64_x86_64_relocate_section
  PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
	 Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
static boolean elf64_x86_64_finish_dynamic_symbol
  PARAMS ((bfd *, struct bfd_link_info *, struct elf_link_hash_entry *,
	   Elf_Internal_Sym *sym));
static boolean elf64_x86_64_finish_dynamic_sections
  PARAMS ((bfd *, struct bfd_link_info *));

/* Given a BFD reloc type, return a HOWTO structure.  */
static reloc_howto_type *
elf64_x86_64_reloc_type_lookup (abfd, code)
     bfd *abfd ATTRIBUTE_UNUSED;
     bfd_reloc_code_real_type code;
{
  unsigned int i;
  for (i = 0; i < sizeof (x86_64_reloc_map) / sizeof (struct elf_reloc_map);
       i++)
    {
      if (x86_64_reloc_map[i].bfd_reloc_val == code)
	return &x86_64_elf_howto_table[(int)
				       x86_64_reloc_map[i].elf_reloc_val];
    }
  return 0;
}

/* Given an x86_64 ELF reloc type, fill in an arelent structure.  */

static void
elf64_x86_64_info_to_howto (abfd, cache_ptr, dst)
     bfd *abfd ATTRIBUTE_UNUSED;
     arelent *cache_ptr;
     Elf64_Internal_Rela *dst;
{
  unsigned r_type;

  r_type = ELF64_R_TYPE (dst->r_info);
  BFD_ASSERT (r_type < (unsigned int) R_X86_64_max);
  cache_ptr->howto = &x86_64_elf_howto_table[r_type];
  BFD_ASSERT (r_type == cache_ptr->howto->type);
}

/* Functions for the x86-64 ELF linker.	 */

/* The name of the dynamic interpreter.	 This is put in the .interp
   section.  */

#define ELF_DYNAMIC_INTERPRETER "/lib/ld64.so.1"

/* The size in bytes of an entry in the global offset table.  */

#define GOT_ENTRY_SIZE 8

/* The size in bytes of an entry in the procedure linkage table.  */

#define PLT_ENTRY_SIZE 16

/* The first entry in a procedure linkage table looks like this.  See the
   SVR4 ABI i386 supplement and the x86-64 ABI to see how this works.  */

static const bfd_byte elf64_x86_64_plt0_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0x35, 8, 0, 0, 0,	/* pushq GOT+8(%rip)  */
  0xff, 0x25, 16, 0, 0, 0,	/* jmpq *GOT+16(%rip) */
  0x90, 0x90, 0x90, 0x90	/* pad out to 16 bytes with nops.  */
};

/* Subsequent entries in a procedure linkage table look like this.  */

static const bfd_byte elf64_x86_64_plt_entry[PLT_ENTRY_SIZE] =
{
  0xff, 0x25,	/* jmpq *name@GOTPC(%rip) */
  0, 0, 0, 0,	/* replaced with offset to this symbol in .got.	 */
  0x68,		/* pushq immediate */
  0, 0, 0, 0,	/* replaced with index into relocation table.  */
  0xe9,		/* jmp relative */
  0, 0, 0, 0	/* replaced with offset to start of .plt0.  */
};

/* The x86-64 linker needs to keep track of the number of relocs that
   it decides to copy in check_relocs for each symbol.	This is so
   that it can discard PC relative relocs if it doesn't need them when
   linking with -Bsymbolic.  We store the information in a field
   extending the regular ELF linker hash table.	 */

/* This structure keeps track of the number of PC relative relocs we
   have copied for a given symbol.  */

struct elf64_x86_64_pcrel_relocs_copied
{
  /* Next section.  */
  struct elf64_x86_64_pcrel_relocs_copied *next;
  /* A section in dynobj.  */
  asection *section;
  /* Number of relocs copied in this section.  */
  bfd_size_type count;
};

/* x86-64 ELF linker hash entry.  */

struct elf64_x86_64_link_hash_entry
{
  struct elf_link_hash_entry root;

  /* Number of PC relative relocs copied for this symbol.  */
  struct elf64_x86_64_pcrel_relocs_copied *pcrel_relocs_copied;
};

/* x86-64  ELF linker hash table.  */

struct elf64_x86_64_link_hash_table
{
  struct elf_link_hash_table root;
};

/* Declare this now that the above structures are defined.  */

static boolean elf64_x86_64_discard_copies
  PARAMS ((struct elf64_x86_64_link_hash_entry *, PTR));

/* Traverse an x86-64 ELF linker hash table.  */

#define elf64_x86_64_link_hash_traverse(table, func, info)		\
  (elf_link_hash_traverse						\
   (&(table)->root,							\
    (boolean (*) PARAMS ((struct elf_link_hash_entry *, PTR))) (func),	\
    (info)))

/* Get the x86-64 ELF linker hash table from a link_info structure.  */

#define elf64_x86_64_hash_table(p) \
  ((struct elf64_x86_64_link_hash_table *) ((p)->hash))

/* Create an entry in an x86-64 ELF linker hash table.	*/

static struct bfd_hash_entry *
elf64_x86_64_link_hash_newfunc (entry, table, string)
     struct bfd_hash_entry *entry;
     struct bfd_hash_table *table;
     const char *string;
{
  struct elf64_x86_64_link_hash_entry *ret =
    (struct elf64_x86_64_link_hash_entry *) entry;

  /* Allocate the structure if it has not already been allocated by a
     subclass.	*/
  if (ret == (struct elf64_x86_64_link_hash_entry *) NULL)
    ret = ((struct elf64_x86_64_link_hash_entry *)
	   bfd_hash_allocate (table,
			      sizeof (struct elf64_x86_64_link_hash_entry)));
  if (ret == (struct elf64_x86_64_link_hash_entry *) NULL)
    return (struct bfd_hash_entry *) ret;

  /* Call the allocation method of the superclass.  */
  ret = ((struct elf64_x86_64_link_hash_entry *)
	 _bfd_elf_link_hash_newfunc ((struct bfd_hash_entry *) ret,
				     table, string));
  if (ret != (struct elf64_x86_64_link_hash_entry *) NULL)
    {
      ret->pcrel_relocs_copied = NULL;
    }

  return (struct bfd_hash_entry *) ret;
}

/* Create an X86-64 ELF linker hash table.  */

static struct bfd_link_hash_table *
elf64_x86_64_link_hash_table_create (abfd)
     bfd *abfd;
{
  struct elf64_x86_64_link_hash_table *ret;

  ret = ((struct elf64_x86_64_link_hash_table *)
	 bfd_alloc (abfd, sizeof (struct elf64_x86_64_link_hash_table)));
  if (ret == (struct elf64_x86_64_link_hash_table *) NULL)
    return NULL;

  if (! _bfd_elf_link_hash_table_init (&ret->root, abfd,
				       elf64_x86_64_link_hash_newfunc))
    {
      bfd_release (abfd, ret);
      return NULL;
    }

  return &ret->root.root;
}

boolean
elf64_x86_64_elf_object_p (abfd)
     bfd *abfd;
{
  /* Set the right machine number for an x86-64 elf64 file.  */
  bfd_default_set_arch_mach (abfd, bfd_arch_i386, bfd_mach_x86_64);
  return true;
}

/* Look through the relocs for a section during the first phase, and
   allocate space in the global offset table or procedure linkage
   table.  */

static boolean
elf64_x86_64_check_relocs (abfd, info, sec, relocs)
     bfd *abfd;
     struct bfd_link_info *info;
     asection *sec;
     const Elf_Internal_Rela *relocs;
{
  bfd *dynobj;
  Elf_Internal_Shdr *symtab_hdr;
  struct elf_link_hash_entry **sym_hashes;
  bfd_signed_vma *local_got_refcounts;
  const Elf_Internal_Rela *rel;
  const Elf_Internal_Rela *rel_end;
  asection *sgot;
  asection *srelgot;
  asection *sreloc;

  if (info->relocateable)
    return true;

  dynobj = elf_hash_table (info)->dynobj;
  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
  sym_hashes = elf_sym_hashes (abfd);
  local_got_refcounts = elf_local_got_refcounts (abfd);

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

      r_symndx = ELF64_R_SYM (rel->r_info);
      if (r_symndx < symtab_hdr->sh_info)
	h = NULL;
      else
	h = sym_hashes[r_symndx - symtab_hdr->sh_info];

      /* Some relocs require a global offset table.  */
      if (dynobj == NULL)
	{
	  switch (ELF64_R_TYPE (rel->r_info))
	    {
	    case R_X86_64_GOT32:
	    case R_X86_64_GOTPCREL:
	      elf_hash_table (info)->dynobj = dynobj = abfd;
	      if (! _bfd_elf_create_got_section (dynobj, info))
		return false;
	      break;
	    }
	}

      switch (ELF64_R_TYPE (rel->r_info))
	{
	case R_X86_64_GOTPCREL:
	case R_X86_64_GOT32:
	  /* This symbol requires a global offset table entry.	*/

	  if (sgot == NULL)
	    {
	      sgot = bfd_get_section_by_name (dynobj, ".got");
	      BFD_ASSERT (sgot != NULL);
	    }

	  if (srelgot == NULL && (h != NULL || info->shared))
	    {
	      srelgot = bfd_get_section_by_name (dynobj, ".rela.got");
	      if (srelgot == NULL)
		{
		  srelgot = bfd_make_section (dynobj, ".rela.got");
		  if (srelgot == NULL
		      || ! bfd_set_section_flags (dynobj, srelgot,
						  (SEC_ALLOC
						   | SEC_LOAD
						   | SEC_HAS_CONTENTS
						   | SEC_IN_MEMORY
						   | SEC_LINKER_CREATED
						   | SEC_READONLY))
		      || ! bfd_set_section_alignment (dynobj, srelgot, 3))
		    return false;
		}
	    }

	  if (h != NULL)
	    {
	      if (h->got.refcount == -1)
		{
		  h->got.refcount = 1;

		  /* Make sure this symbol is output as a dynamic symbol.  */
		  if (h->dynindx == -1)
		    {
		      if (! bfd_elf64_link_record_dynamic_symbol (info, h))
			return false;
		    }

		  sgot->_raw_size += GOT_ENTRY_SIZE;
		  srelgot->_raw_size += sizeof (Elf64_External_Rela);
		}
	      else
		h->got.refcount += 1;
	    }
	  else
	    {
	      /* This is a global offset table entry for a local symbol.  */
	      if (local_got_refcounts == NULL)
		{
		  size_t size;

		  size = symtab_hdr->sh_info * sizeof (bfd_signed_vma);
		  local_got_refcounts = ((bfd_signed_vma *)
					 bfd_alloc (abfd, size));
		  if (local_got_refcounts == NULL)
		    return false;
		  elf_local_got_refcounts (abfd) = local_got_refcounts;
		  memset (local_got_refcounts, -1, size);
		}
	      if (local_got_refcounts[r_symndx] == -1)
		{
		  local_got_refcounts[r_symndx] = 1;

		  sgot->_raw_size += GOT_ENTRY_SIZE;
		  if (info->shared)
		    {
		      /* If we are generating a shared object, we need to
			 output a R_X86_64_RELATIVE reloc so that the dynamic
			 linker can adjust this GOT entry.  */
		      srelgot->_raw_size += sizeof (Elf64_External_Rela);
		    }
		}
	      else
		local_got_refcounts[r_symndx] += 1;
	    }
	  break;

	case R_X86_64_PLT32:
	  /* This symbol requires a procedure linkage table entry.  We
	     actually build the entry in adjust_dynamic_symbol,
	     because this might be a case of linking PIC code which is
	     never referenced by a dynamic object, in which case we
	     don't need to generate a procedure linkage table entry
	     after all.	 */

	  /* If this is a local symbol, we resolve it directly without
	     creating a procedure linkage table entry.	*/
	  if (h == NULL)
	    continue;

	  h->elf_link_hash_flags |= ELF_LINK_HASH_NEEDS_PLT;
	  if (h->plt.refcount == -1)
	    h->plt.refcount = 1;
	  else
	    h->plt.refcount += 1;
	  break;

	case R_X86_64_8:
	case R_X86_64_16:
	case R_X86_64_32: