/* PPC specific symbolic name handling.
   Copyright (C) 2004, 2005 Red Hat, Inc.
   Written by Ulrich Drepper <drepper@redhat.com>, 2004.

   This program is Open Source software; you can redistribute it and/or
   modify it under the terms of the Open Software License version 1.0 as
   published by the Open Source Initiative.

   You should have received a copy of the Open Software License along
   with this program; if not, you may obtain a copy of the Open Software
   License version 1.0 from http://www.opensource.org/licenses/osl.php or
   by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
   3001 King Ranch Road, Ukiah, CA 95482.   */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include <elf.h>
#include <stddef.h>
#include <string.h>

#define BACKEND		ppc_
#include "libebl_CPU.h"


/* Check for the simple reloc types.  */
Elf_Type
ppc_reloc_simple_type (Ebl *ebl __attribute__ ((unused)), int type)
{
  switch (type)
    {
    case R_PPC_ADDR32:
    case R_PPC_UADDR32:
      return ELF_T_WORD;
    case R_PPC_UADDR16:
      return ELF_T_HALF;
    default:
      return ELF_T_NUM;
    }
}


const char *
ppc_dynamic_tag_name (int64_t tag, char *buf __attribute__ ((unused)),
		      size_t len __attribute__ ((unused)))
{
  switch (tag)
    {
    case DT_PPC_GOT:
      return "PPC_GOT";
    default:
      break;
    }
  return NULL;
}


bool
ppc_dynamic_tag_check (int64_t tag)
{
  return tag == DT_PPC_GOT;
}


/* Look for DT_PPC_GOT.  */
static bool
find_dyn_got (Elf *elf, GElf_Ehdr *ehdr, GElf_Addr *addr)
{
  for (int i = 0; i < ehdr->e_phnum; ++i)
    {
      GElf_Phdr phdr_mem;
      GElf_Phdr *phdr = gelf_getphdr (elf, i, &phdr_mem);
      if (phdr == NULL || phdr->p_type != PT_DYNAMIC)
	continue;

      Elf_Scn *scn = gelf_offscn (elf, phdr->p_offset);
      GElf_Shdr shdr_mem;
      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
      Elf_Data *data = elf_getdata (scn, NULL);
      if (shdr != NULL && shdr->sh_type == SHT_DYNAMIC && data != NULL)
	for (unsigned int j = 0; j < shdr->sh_size / shdr->sh_entsize; ++j)
	  {
	    GElf_Dyn dyn_mem;
	    GElf_Dyn *dyn = gelf_getdyn (data, j, &dyn_mem);
	    if (dyn != NULL && dyn->d_tag == DT_PPC_GOT)
	      {
		*addr = dyn->d_un.d_ptr;
		return true;
	      }
	  }

      /* There is only one PT_DYNAMIC entry.  */
      break;
    }

  return false;
}


/* Check whether given symbol's st_value and st_size are OK despite failing
   normal checks.  */
bool
ppc_check_special_symbol (Elf *elf, GElf_Ehdr *ehdr, const GElf_Sym *sym,
			  const char *name, const GElf_Shdr *destshdr)
{
  if (name == NULL)
    return false;

  if (strcmp (name, "_GLOBAL_OFFSET_TABLE_") == 0)
    {
      GElf_Addr gotaddr;
      if (find_dyn_got (elf, ehdr, &gotaddr))
	return sym->st_value == gotaddr;
      return sym->st_value == destshdr->sh_addr + 4;
    }

  const char *sname = elf_strptr (elf, ehdr->e_shstrndx, destshdr->sh_name);
  if (sname == NULL)
    return false;

  if (strcmp (name, "_SDA_BASE_") == 0)
    return (strcmp (sname, ".sdata") == 0
	    && sym->st_value == destshdr->sh_addr + 0x8000
	    && sym->st_size == 0);

  if (strcmp (name, "_SDA2_BASE_") == 0)
    return (strcmp (sname, ".sdata2") == 0
	    && sym->st_value == destshdr->sh_addr + 0x8000
	    && sym->st_size == 0);

  return false;
}


/* Check if backend uses a bss PLT in this file.  */
bool
ppc_bss_plt_p (Elf *elf, GElf_Ehdr *ehdr)
{
  GElf_Addr addr;
  return ! find_dyn_got (elf, ehdr, &addr);
}