xref: /src/external/gpl3/gdb/dist/bfd/elfxx-kvx.c

/* KVX-specific support for ELF.
   Copyright (C) 2009-2024 Free Software Foundation, Inc.
   Contributed by Kalray SA.

   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; see the file COPYING3. If not,
   see <http://www.gnu.org/licenses/>.  */

#include "sysdep.h"
#include "elfxx-kvx.h"
#include <stdarg.h>
#include <string.h>

/* Return non-zero if the indicated VALUE has overflowed the maximum
   range expressible by a unsigned number with the indicated number of
   BITS.  */

static bfd_reloc_status_type
kvx_unsigned_overflow (bfd_vma value, unsigned int bits)
{
  bfd_vma lim;
  if (bits >= sizeof (bfd_vma) * 8)
    return bfd_reloc_ok;
  lim = (bfd_vma) 1 << bits;
  if (value >= lim)
    return bfd_reloc_overflow;
  return bfd_reloc_ok;
}

/* Return non-zero if the indicated VALUE has overflowed the maximum
   range expressible by an signed number with the indicated number of
   BITS.  */

static bfd_reloc_status_type
kvx_signed_overflow (bfd_vma value, unsigned int bits)
{
  bfd_vma lim;

  if (bits >= sizeof (bfd_vma) * 8)
    return bfd_reloc_ok;
  lim = (bfd_vma) 1 << (bits - 1);
  if (value + lim >= lim * 2)
    return bfd_reloc_overflow;
  return bfd_reloc_ok;
}

/* Insert the addend/value into the instruction or data object being
   relocated.  */
bfd_reloc_status_type
_bfd_kvx_elf_put_addend (bfd *abfd,
			 bfd_byte *address,
			 bfd_reloc_code_real_type r_type ATTRIBUTE_UNUSED,
			 reloc_howto_type *howto,
			 bfd_signed_vma addend)
{
  bfd_reloc_status_type status = bfd_reloc_ok;
  bfd_vma contents;
  int size;

  size = bfd_get_reloc_size (howto);
  switch (size)
    {
    case 2:
      contents = bfd_get_16 (abfd, address);
      break;
    case 4:
      if (howto->src_mask != 0xffffffff)
	/* Must be 32-bit instruction, always little-endian.  */
	contents = bfd_getl32 (address);
      else
	/* Must be 32-bit data (endianness dependent).  */
	contents = bfd_get_32 (abfd, address);
      break;
    case 8:
      contents = bfd_get_64 (abfd, address);
      break;
    default:
      abort ();
    }

  switch (howto->complain_on_overflow)
    {
    case complain_overflow_dont:
      break;
    case complain_overflow_signed:
      status = kvx_signed_overflow (addend,
				    howto->bitsize + howto->rightshift);
      break;
    case complain_overflow_unsigned:
      status = kvx_unsigned_overflow (addend,
				      howto->bitsize + howto->rightshift);
      break;
    case complain_overflow_bitfield:
    default:
      abort ();
    }

  addend >>= howto->rightshift;

  /* FIXME KVX : AARCH64 is "redoing" what the link_relocate bfd
   * function does ie. extract bitfields and apply then to the
   * existing content (insn) (howto's job) Not sure exactly
   * why. Maybe because we need this even when not applying reloc
   * against a input_bfd (eg. when doing PLT).  On KVX, we have not
   * reached a point where we would need to write similar
   * functions for each insn. So we'll simply enrich the default
   * case for handling a bit more than "right aligned bitfields"
   *
   * Beware that this won't be able to apply generic howto !
   */

  /* if (howto->dst_mask & (howto->dst_mask + 1)) */
  /* 	return bfd_reloc_notsupported; */
  addend <<= howto->bitpos;
  contents = ((contents & ~howto->dst_mask) | (addend & howto->dst_mask));

  switch (size)
    {
    case 2:
      bfd_put_16 (abfd, contents, address);
      break;
    case 4:
      if (howto->dst_mask != 0xffffffff)
	/* must be 32-bit instruction, always little-endian */
	bfd_putl32 (contents, address);
      else
	/* must be 32-bit data (endianness dependent) */
	bfd_put_32 (abfd, contents, address);
      break;
    case 8:
      bfd_put_64 (abfd, contents, address);
      break;
    default:
      abort ();
    }

  return status;
}

bool
_bfd_kvx_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
{
  int offset;
  size_t size;

  switch (note->descsz)
    {
    case 680: /* sizeof(struct elf_prstatus) on Linux/kvx.  */
      /* pr_cursig */
      elf_tdata (abfd)->core->signal = bfd_get_16 (abfd, note->descdata + 12);

      /* pr_pid */
      elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 32);

      /* pr_reg */
      offset = 112;
      size = 560;
      break;

    default:
      return false;
    }

  /* Make a ".reg/999" section.  */
  return _bfd_elfcore_make_pseudosection (abfd, ".reg", size,
					  note->descpos + offset);
}

bool
_bfd_kvx_elf_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
{
  switch (note->descsz)
    {
    case 136: /* This is sizeof(struct elf_prpsinfo) on Linux/kvx.  */
      elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 24);
      elf_tdata (abfd)->core->program
	= _bfd_elfcore_strndup (abfd, note->descdata + 40, 16);
      elf_tdata (abfd)->core->command
	= _bfd_elfcore_strndup (abfd, note->descdata + 56, 80);
      break;

    default:
      return false;
    }

  /* Note that for some reason, a spurious space is tacked
     onto the end of the args in some (at least one anyway)
     implementations, so strip it off if it exists.  */

  {
    char *command = elf_tdata (abfd)->core->command;
    int n = strlen (command);

    if (n > 0 && command[n - 1] == ' ')
      command[n - 1] = 0;
  }

  return true;
}