/* Adapteva epiphany specific support for 32-bit ELF

   Copyright (C) 2000-2023 Free Software Foundation, Inc.

   Contributed by Embecosm on behalf of Adapteva, 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/epiphany.h"

#include "libiberty.h"

/* Struct used to pass miscellaneous paramaters which

   helps to avoid overly long parameter lists.  */

struct misc

{

  Elf_Internal_Shdr *  symtab_hdr;

  Elf_Internal_Rela *  irelbase;

  bfd_byte *         contents;

  Elf_Internal_Sym *   isymbuf;

};

struct epiphany_opcode

{

  unsigned short opcode;

  unsigned short mask;

};

static bool epiphany_relaxed = false;

/* Relocation tables.  */

static reloc_howto_type epiphany_elf_howto_table [] =

{

#define AHOW(t,rs,s,bs,pr,bp,co,name,sm,dm) \

    HOWTO(t,      /* type */ \

    rs,     /* rightshift */ \

    s,      /* size */ \

    bs,     /* bitsize */ \

    pr,     /* pc_relative */ \

    bp,     /* bitpos */ \

    co,     /* complain_on_overflow */         \

    bfd_elf_generic_reloc,/* special_function */ \

    name,     /* name */ \

    false,    /* partial_inplace */ \

    sm,     /* src_mask */ \

    dm,     /* dst_mask */ \

    pr)     /* pcrel_offset */

  /* This reloc does nothing.  */

  AHOW (R_EPIPHANY_NONE,    0, 0,0, false, 0, complain_overflow_dont,   "R_EPIPHANY_NONE",      0,    0),

  /* 8 bit absolute (not likely) */

  AHOW (R_EPIPHANY_8,     0, 1, 8, false, 0, complain_overflow_bitfield, "R_EPIPHANY_8",  0x000000ff, 0x000000ff),

  /* 16 bit absolute */

  AHOW (R_EPIPHANY_16,      0, 2,16, false, 0, complain_overflow_bitfield, "R_EPIPHANY_16", 0x0000ffff, 0x00ff1fe0),

  /* A 32 bit absolute relocation.  */

  AHOW (R_EPIPHANY_32,      0, 4,32, false, 0, complain_overflow_dont,     "R_EPIPHANY_32", 0xffffffff, 0xffffffff),

  /*  8 bit relative relocation */

  HOWTO ( R_EPIPHANY_8_PCREL,  0, 1,  8, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_EPIPHANY_8_PCREL", false, 0x000000ff, 0x000000ff, false),

  /* 16 bit relative relocation */

  HOWTO ( R_EPIPHANY_16_PCREL, 0, 2, 16, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_EPIPHANY_8_PCREL", false, 0x000000ff, 0x000000ff, false),

  /* 32 bit relative relocation */

  HOWTO ( R_EPIPHANY_32_PCREL, 0, 4, 32, true, 0, complain_overflow_bitfield, bfd_elf_generic_reloc, "R_EPIPHANY_8_PCREL", false, 0x000000ff, 0x000000ff, false),

  /* 8 bit pc-relative relocation */

  AHOW (R_EPIPHANY_SIMM8,   1, 1, 8,  true, 8, complain_overflow_signed,   "R_EPIPHANY_SIMM8",   0x000000ff, 0x0000ff00),

  /* 24 bit pc-relative relocation */

  AHOW (R_EPIPHANY_SIMM24,  1, 4,24,  true, 8, complain_overflow_signed,   "R_EPIPHANY_SIMM24",  0x00ffffff, 0xffffff00),

  /* %HIGH(EA) */

  AHOW (R_EPIPHANY_HIGH,    0, 4,16, false, 0, complain_overflow_dont,     "R_EPIPHANY_HIGH",  0x0ff01fe0, 0x0ff01fe0),

  /* %LOW(EA) */

  AHOW (R_EPIPHANY_LOW,     0, 4,16, false, 0, complain_overflow_dont,  "R_EPIPHANY_LOW",     0x0ff01fe0, 0x0ff01fe0),

  /* simm11 */

  AHOW (R_EPIPHANY_SIMM11,  0, 4,11, false, 0, complain_overflow_bitfield, "R_EPIPHANY_SIMM11",  0x00ff0380, 0x00ff0380),

  /* imm12 - sign-magnitude */

  AHOW (R_EPIPHANY_IMM11,   0, 4,11, false, 0, complain_overflow_bitfield, "R_EPIPHANY_IMM12",   0x00ff0380, 0x00ff0380),

  /* imm8 */

  AHOW (R_EPIPHANY_IMM8,    0, 2, 8, false, 8, complain_overflow_signed,   "R_EPIPHANY_IMM8",  0x0000ff00, 0x0000ff00)

};

#undef AHOW

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

static reloc_howto_type *

epiphany_reloc_type_lookup (bfd * abfd ATTRIBUTE_UNUSED,

          bfd_reloc_code_real_type code)

{

  /* Note that the epiphany_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/epiphany.h.  */

  switch (code)

    {

    case BFD_RELOC_NONE:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_NONE];

    case BFD_RELOC_EPIPHANY_SIMM8:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_SIMM8];

    case BFD_RELOC_EPIPHANY_SIMM24:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_SIMM24];

    case BFD_RELOC_8_PCREL:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_8_PCREL];

    case BFD_RELOC_16_PCREL:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_16_PCREL];

    case BFD_RELOC_32_PCREL:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_32_PCREL];

    case BFD_RELOC_8:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_8];

    case BFD_RELOC_16:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_16];

    case BFD_RELOC_32:

      return &epiphany_elf_howto_table[ (int) R_EPIPHANY_32];

    case BFD_RELOC_EPIPHANY_HIGH:

      return & epiphany_elf_howto_table[ (int) R_EPIPHANY_HIGH];

    case BFD_RELOC_EPIPHANY_LOW:

      return & epiphany_elf_howto_table[ (int) R_EPIPHANY_LOW];

    case BFD_RELOC_EPIPHANY_SIMM11:

      return & epiphany_elf_howto_table[ (int) R_EPIPHANY_SIMM11];

    case BFD_RELOC_EPIPHANY_IMM11:

      return & epiphany_elf_howto_table[ (int) R_EPIPHANY_IMM11];

    case BFD_RELOC_EPIPHANY_IMM8:

      return & epiphany_elf_howto_table[ (int) R_EPIPHANY_IMM8];

    default:

      /* Pacify gcc -Wall.  */

      return NULL;

    }

  return NULL;

}

static reloc_howto_type *

epiphany_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED, const char *r_name)

{

  unsigned int i;

  for (i = 0; i < ARRAY_SIZE (epiphany_elf_howto_table); i++)

    if (epiphany_elf_howto_table[i].name != NULL

  && strcasecmp (epiphany_elf_howto_table[i].name, r_name) == 0)

      return &epiphany_elf_howto_table[i];

  return NULL;

}

#define PAGENO(ABSADDR) ((ABSADDR) & 0xFFFFC000)

#define BASEADDR(SEC) ((SEC)->output_section->vma + (SEC)->output_offset)

/* This function handles relaxing for the epiphany.

   Dummy placeholder for future optimizations.  */

static bool

epiphany_elf_relax_section (bfd *abfd, asection *sec,

          struct bfd_link_info *link_info,

          bool *again)

{

  Elf_Internal_Shdr *symtab_hdr;

  Elf_Internal_Rela *internal_relocs;

  bfd_byte *contents = NULL;

  Elf_Internal_Sym *isymbuf = NULL;

  static asection * first_section = NULL;

  static unsigned long search_addr;

  static unsigned long page_start = 0;

  static unsigned long page_end = 0;

  static unsigned int pass = 0;

  static bool new_pass = false;

  static bool changed = false;

  struct misc misc ATTRIBUTE_UNUSED;

  asection *stab;

  /* Assume nothing changes.  */

  *again = false;

  if (first_section == NULL)

    {

      epiphany_relaxed = true;

      first_section = sec;

    }

  if (first_section == sec)

    {

      pass++;

      new_pass = true;

    }

  /* We don't have to do anything for a relocatable link,

     if this section does not have relocs, or if this is

     not a code section.  */

  if (bfd_link_relocatable (link_info)

      || sec->reloc_count == 0

      || (sec->flags & SEC_RELOC) == 0

      || (sec->flags & SEC_HAS_CONTENTS) == 0

      || (sec->flags & SEC_CODE) == 0)

    return true;

  symtab_hdr = &elf_tdata (abfd)->symtab_hdr;

  internal_relocs = _bfd_elf_link_read_relocs (abfd, sec, NULL, NULL,

                 link_info->keep_memory);

  if (internal_relocs == NULL)

    goto error_return;

  /* Make sure the stac.rela stuff gets read in.  */

  stab = bfd_get_section_by_name (abfd, ".stab");

  if (stab)

    {

      /* So stab does exits.  */

      Elf_Internal_Rela * irelbase ATTRIBUTE_UNUSED;

      irelbase = _bfd_elf_link_read_relocs (abfd, stab, NULL, NULL,

              link_info->keep_memory);

    }

  /* Get section contents cached copy if it exists.  */

  if (contents == NULL)

    {

      /* Get cached copy if it exists.  */

      if (elf_section_data (sec)->this_hdr.contents != NULL)

  contents = elf_section_data (sec)->this_hdr.contents;

      else

  {

    /* Go get them off disk.  */

    if (!bfd_malloc_and_get_section (abfd, sec, &contents))

      goto error_return;

  }

    }

  /* Read this BFD's symbols cached copy if it exists.  */

  if (isymbuf == NULL && symtab_hdr->sh_info != 0)

    {

      isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents;

      if (isymbuf == NULL)

  isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr,

          symtab_hdr->sh_info, 0,

          NULL, NULL, NULL);

      if (isymbuf == NULL)

  goto error_return;

    }

  misc.symtab_hdr = symtab_hdr;

  misc.isymbuf = isymbuf;

  misc.irelbase = internal_relocs;

  misc.contents = contents;

  /* This is where all the relaxation actually get done.  */

  if ((pass == 1) || (new_pass && !changed))

    {

      /* On the first pass we simply search for the lowest page that

   we havn't relaxed yet. Note that the pass count is reset

   each time a page is complete in order to move on to the next page.

   If we can't find any more pages then we are finished.  */

      if (new_pass)

  {

    pass = 1;

    new_pass = false;

    changed = true; /* Pre-initialize to break out of pass 1.  */

    search_addr = 0xFFFFFFFF;

  }

      if ((BASEADDR (sec) + sec->size < search_addr)

    && (BASEADDR (sec) + sec->size > page_end))

  {

    if (BASEADDR (sec) <= page_end)

      search_addr = page_end + 1;

    else

      search_addr = BASEADDR (sec);

    /* Found a page => more work to do.  */

    *again = true;

  }

    }

  else

    {

      if (new_pass)

  {

    new_pass = false;

    changed = false;

    page_start = PAGENO (search_addr);

    page_end = page_start | 0x00003FFF;

  }

      /* Only process sections in range.  */

      if ((BASEADDR (sec) + sec->size >= page_start)

    && (BASEADDR (sec) <= page_end))

  {

#if 0

    if (!epiphany_elf_relax_section_page (abfd, sec, &changed, &misc,

            page_start, page_end))

#endif

      return false;

  }

      *again = true;

    }

  /* Perform some house keeping after relaxing the section.  */

  if (isymbuf != NULL

      && symtab_hdr->contents != (unsigned char *) isymbuf)

    {

      if (! link_info->keep_memory)

  free (isymbuf);

      else

  symtab_hdr->contents = (unsigned char *) isymbuf;

    }

  if (contents != NULL

      && elf_section_data (sec)->this_hdr.contents != contents)

    {

      if (! link_info->keep_memory)

  free (contents);

      else

  {

    /* Cache the section contents for elf_link_input_bfd.  */

    elf_section_data (sec)->this_hdr.contents = contents;

  }

    }

  if (elf_section_data (sec)->relocs != internal_relocs)

    free (internal_relocs);

  return true;

 error_return:

  if (symtab_hdr->contents != (unsigned char *) isymbuf)

    free (isymbuf);

  if (elf_section_data (sec)->this_hdr.contents != contents)

    free (contents);

  if (elf_section_data (sec)->relocs != internal_relocs)

    free (internal_relocs);

  return false;

}

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

static bool

epiphany_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_EPIPHANY_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 = & epiphany_elf_howto_table [r_type];

  return true;

}

/* Perform a single relocation.

   By default we use the standard BFD routines.  */

static bfd_reloc_status_type

epiphany_final_link_relocate (reloc_howto_type *  howto,

            bfd *     input_bfd,

            asection *    input_section,

            bfd_byte *    contents,

            Elf_Internal_Rela * rel,

            bfd_vma     relocation)

{

  switch (howto->type)

    {

      /* Handle 16 bit immediates.  */

    case R_EPIPHANY_HIGH:

      relocation += rel->r_addend;

      relocation >>= 16;

      goto common;

    case R_EPIPHANY_LOW:

      relocation += rel->r_addend;

    common:

      relocation = ((relocation & 0xff00L) << 12)

  | ((relocation & 0x00ffL) << 5);

      /* Sanity check the address.  */

      if (rel->r_offset > bfd_get_section_limit (input_bfd, input_section))

  return bfd_reloc_outofrange;

      return _bfd_relocate_contents (howto, input_bfd, relocation,

             contents + rel->r_offset);

    case R_EPIPHANY_SIMM11:

      relocation += rel->r_addend;

      /* Check signed overflow.  */

      if ((int)relocation > 1023 || (int)relocation < -1024)

  return bfd_reloc_outofrange;

      goto disp11;

    case R_EPIPHANY_IMM11:

      relocation += rel->r_addend;

      if ((unsigned int) relocation > 0x7ff)

  return bfd_reloc_outofrange;

      /* Fall through.  */

    disp11:

      relocation = (((relocation & 7) << 5)

        | ((relocation & 0x7f8 ) << 13));

      return _bfd_relocate_contents (howto, input_bfd, relocation,

             contents + rel->r_offset);

      /* Pass others through.  */

    default:

      break;

    }

  /* Only install relocation if above tests did not disqualify it.  */

  return _bfd_final_link_relocate (howto, input_bfd, input_section,

           contents, rel->r_offset,

           relocation, rel->r_addend);

}

/* Relocate an EPIPHANY ELF section.

   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

epiphany_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 ATTRIBUTE_UNUSED;

      r_type = ELF32_R_TYPE (rel->r_info);

      r_symndx = ELF32_R_SYM (rel->r_info);

      howto  = epiphany_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 = BASEADDR (sec) + sym->st_value;

    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 warned ATTRIBUTE_UNUSED;

    bool unresolved_reloc ATTRIBUTE_UNUSED;

    bool ignored ATTRIBUTE_UNUSED;

    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 EPIPHANY-specific part.  */

      r = epiphany_final_link_relocate (howto, input_bfd, input_section,

             contents, rel, relocation);

      if (r != bfd_reloc_ok)

  {

    const char * msg = 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;

        /* This is how epiphany_final_link_relocate tells us of a

     non-kosher reference between insn & data address spaces.  */

      case bfd_reloc_notsupported:

        if (sym != NULL) /* Only if it's not an unresolved symbol.  */

     msg = _("unsupported relocation between data/insn address spaces");

        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;

}

/* We only have a little-endian target.  */

#define TARGET_LITTLE_SYM  epiphany_elf32_vec

#define TARGET_LITTLE_NAME  "elf32-epiphany"

#define ELF_ARCH   bfd_arch_epiphany

#define ELF_MACHINE_CODE EM_ADAPTEVA_EPIPHANY

#define ELF_MAXPAGESIZE  0x8000 /* No pages on the EPIPHANY.  */

#define elf_info_to_howto_rel     NULL

#define elf_info_to_howto     epiphany_info_to_howto_rela

#define elf_backend_can_gc_sections   1

#define elf_backend_rela_normal     1

#define elf_backend_relocate_section    epiphany_elf_relocate_section

#define elf_symbol_leading_char     '_'

#define bfd_elf32_bfd_reloc_type_lookup   epiphany_reloc_type_lookup

#define bfd_elf32_bfd_reloc_name_lookup   epiphany_reloc_name_lookup

#define bfd_elf32_bfd_relax_section   epiphany_elf_relax_section

#include "elf32-target.h"