elfloader-x86.c

/*
 * Copyright (c) 2005, Swedish Institute of Computer Science
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This file is part of the Contiki operating system.
 *
 * @(#)$Id: elfloader-x86.c,v 1.3 2009/02/27 14:28:02 nvt-se Exp $
 */
#include "elfloader-arch.h"
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>

#define R_386_NONE          0
#define R_386_32            1
#define R_386_PC32          2
#define R_386_GOT32         3
#define R_386_PLT32         4
#define R_386_COPY          5
#define R_386_GLOB_DATA     6
#define R_386_JMP_SLOT      7
#define R_386_RELATIVE      8
#define R_386_GOTOFF        9
#define R_386_GOTPC         10

#define ELF32_R_TYPE(info)      ((unsigned char)(info))

static char datamemory[ELFLOADER_DATAMEMORY_SIZE];

/*---------------------------------------------------------------------------*/
void *
elfloader_arch_allocate_ram(int size)
{
  return (void *)datamemory;
}
/*---------------------------------------------------------------------------*/
void *
elfloader_arch_allocate_rom(int size)
{
  int fd = open("/dev/zero", O_RDWR);
  char *mem = mmap(0, ELFLOADER_TEXTMEMORY_SIZE, PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
  return mem;
}
/*---------------------------------------------------------------------------*/
void
elfloader_arch_write_rom(int fd, unsigned short textoff, unsigned int size, char *mem)
{
  cfs_seek(fd, textoff, CFS_SEEK_SET);
  cfs_read(fd, (unsigned char *)mem, size);
}
/*---------------------------------------------------------------------------*/
void
elfloader_arch_relocate(int fd, unsigned int sectionoffset, char *sectionaddress, 
                        struct elf32_rela *rela, char *addr)
{
  unsigned int type;
  
  /* 
     Given value addr is S
     
     S = runtime address of destination = addr
     A = rela->r_addend 
     P = absolute address of relocation (section base address and rela->r_offset)
  */
  
  type = ELF32_R_TYPE(rela->r_info);
  
  switch(type) {
  case R_386_NONE:
  case R_386_COPY:
    /* printf("elfloader-x86.c: relocation calculation completed (none) %d\n", type); */
    break;
  case R_386_32:
    addr += rela->r_addend; /* +A */
    
    cfs_seek(fd, sectionoffset + rela->r_offset, CFS_SEEK_SET);
    cfs_write(fd, (char *)&addr, 4);
    /*printf("elfloader-x86.c: performed relocation type S + A (%d)\n", type);*/
    break;
  case R_386_PC32:
    addr -= (sectionaddress + rela->r_offset); /* -P */
    addr += rela->r_addend; /* +A */
    
    cfs_seek(fd, sectionoffset + rela->r_offset, CFS_SEEK_SET);
    cfs_write(fd, (char *)&addr, 4);
    /*printf("elfloader-x86.c: performed relocation type S + A - P (%d)\n", type);*/
    break;
  case R_386_GOT32:
    printf("elfloader-x86.c: unsupported relocation type G + A - P (%d)\n", type);
    break;
  case R_386_PLT32:
    printf("elfloader-x86.c: unsupported relocation type L + A - P (%d)\n", type);
    break;
  case R_386_GLOB_DATA:
  case R_386_JMP_SLOT:
    printf("elfloader-x86.c: unsupported relocation type S (%d)\n", type);
    break;
  case R_386_RELATIVE:
    printf("elfloader-x86.c: unsupported relocation type B + A (%d)\n", type);
    break;
  case R_386_GOTOFF:
    printf("elfloader-x86.c: unsupported relocation type S + A - GOT (%d)\n", type);
    break;
  case R_386_GOTPC:
    printf("elfloader-x86.c: unsupported relocation type GOT + A - P (%d)\n", type);
    break;
  default:
    printf("elfloader-x86.c: unknown type (%d)\n", type);
    break;
  }
  
}
/*---------------------------------------------------------------------------*/