grub/lib/i386/relocator.c

/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2009  Free Software Foundation, Inc.
 *
 *  GRUB 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.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/mm.h>
#include <grub/misc.h>

#include <grub/types.h>
#include <grub/types.h>
#include <grub/err.h>

#include <grub/i386/relocator.h>

extern grub_uint8_t grub_relocator32_forward_start;
extern grub_uint8_t grub_relocator32_forward_end;
extern grub_uint8_t grub_relocator32_backward_start;
extern grub_uint8_t grub_relocator32_backward_end;

extern grub_uint32_t grub_relocator32_backward_dest;
extern grub_uint32_t grub_relocator32_backward_size;
extern grub_addr_t grub_relocator32_backward_src;

extern grub_uint32_t grub_relocator32_forward_dest;
extern grub_uint32_t grub_relocator32_forward_size;
extern grub_addr_t grub_relocator32_forward_src;

extern grub_uint32_t grub_relocator32_forward_eax;
extern grub_uint32_t grub_relocator32_forward_ebx;
extern grub_uint32_t grub_relocator32_forward_ecx;
extern grub_uint32_t grub_relocator32_forward_edx;
extern grub_uint32_t grub_relocator32_forward_eip;
extern grub_uint32_t grub_relocator32_forward_esp;

extern grub_uint32_t grub_relocator32_backward_eax;
extern grub_uint32_t grub_relocator32_backward_ebx;
extern grub_uint32_t grub_relocator32_backward_ecx;
extern grub_uint32_t grub_relocator32_backward_edx;
extern grub_uint32_t grub_relocator32_backward_eip;
extern grub_uint32_t grub_relocator32_backward_esp;

#define RELOCATOR_SIZEOF(x)	(&grub_relocator32_##x##_end - &grub_relocator32_##x##_start)
#define RELOCATOR_ALIGN 16
#define PREFIX(x) grub_relocator32_ ## x

static void
write_relocator_bw (void *ptr, void *src, grub_uint32_t dest,
		    grub_size_t size, struct grub_relocator32_state state)
{
  void (*entry) ();

  grub_relocator32_backward_dest = dest;
  grub_relocator32_backward_src = PTR_TO_UINT64 (src);
  grub_relocator32_backward_size = size;

  grub_relocator32_backward_eax = state.eax;
  grub_relocator32_backward_ebx = state.ebx;
  grub_relocator32_backward_ecx = state.ecx;
  grub_relocator32_backward_edx = state.edx;
  grub_relocator32_backward_eip = state.eip;
  grub_relocator32_backward_esp = state.esp;

  grub_memmove (ptr,
		&grub_relocator32_backward_start,
		RELOCATOR_SIZEOF (backward));
  entry = (void (*)()) (ptr);
  entry ();
}

static void
write_relocator_bw (void *ptr, void *src, grub_uint32_t dest,
		    grub_size_t size, struct grub_relocator32_state state)
{

  grub_relocator32_forward_dest = dest;
  grub_relocator32_forward_src = PTR_TO_UINT64 (src);
  grub_relocator32_forward_size = size;
  
  grub_relocator32_forward_eax = state.eax;
  grub_relocator32_forward_ebx = state.ebx;
  grub_relocator32_forward_ecx = state.ecx;
  grub_relocator32_forward_edx = state.edx;
  grub_relocator32_forward_eip = state.eip;
  grub_relocator32_forward_esp = state.esp;
  
  grub_memmove (ptr,
		&grub_relocator32_forward_start,
		RELOCATOR_SIZEOF (forward));
  entry = (void (*)()) ptr;
  entry ();
}