grub/lib/i386/relocator.c
Vladimir 'phcoder' Serbinenko 95c7fc3f55 First compileable newreloc
2010-01-10 00:30:33 +01:00

138 lines
3.8 KiB
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>
#include <grub/relocator_private.h>
extern grub_uint8_t grub_relocator32_start;
extern grub_uint8_t grub_relocator32_end;
extern grub_uint8_t grub_relocator_forward_start;
extern grub_uint8_t grub_relocator_forward_end;
extern grub_uint8_t grub_relocator_backward_start;
extern grub_uint8_t grub_relocator_backward_end;
extern void *grub_relocator_backward_dest;
extern void *grub_relocator_backward_src;
extern grub_size_t grub_relocator_backward_size;
extern void *grub_relocator_forward_dest;
extern void *grub_relocator_forward_src;
extern grub_size_t grub_relocator_forward_size;
extern grub_uint32_t grub_relocator32_eax;
extern grub_uint32_t grub_relocator32_ebx;
extern grub_uint32_t grub_relocator32_ecx;
extern grub_uint32_t grub_relocator32_edx;
extern grub_uint32_t grub_relocator32_eip;
extern grub_uint32_t grub_relocator32_esp;
#define RELOCATOR_SIZEOF(x) (&grub_relocator##x##_end - &grub_relocator##x##_start)
grub_size_t grub_relocator_align = 1;
grub_size_t grub_relocator_forward_size;
grub_size_t grub_relocator_backward_size;
grub_size_t grub_relocator_jumper_size = 10;
void
grub_cpu_relocator_init (void)
{
grub_relocator_forward_size = RELOCATOR_SIZEOF(_forward);
grub_relocator_backward_size = RELOCATOR_SIZEOF(_backward);
}
void
grub_cpu_relocator_jumper (void *rels, grub_addr_t addr)
{
grub_uint8_t *ptr;
ptr = rels;
/* jmp $addr */
*(grub_uint8_t *) ptr = 0xe9;
ptr++;
*(grub_uint32_t *) ptr = addr - (grub_uint32_t) (ptr + 4);
ptr += 4;
/* movl $addr, %eax (for relocator) */
*(grub_uint8_t *) ptr = 0xb8;
ptr++;
*(grub_uint32_t *) ptr = addr;
}
void
grub_cpu_relocator_backward (void *ptr, void *src, void *dest,
grub_size_t size)
{
grub_relocator_backward_dest = dest;
grub_relocator_backward_src = src;
grub_relocator_backward_size = size;
grub_memmove (ptr,
&grub_relocator_backward_start,
RELOCATOR_SIZEOF (_backward));
}
void
grub_cpu_relocator_forward (void *ptr, void *src, void *dest,
grub_size_t size)
{
grub_relocator_forward_dest = dest;
grub_relocator_forward_src = src;
grub_relocator_forward_size = size;
grub_memmove (ptr,
&grub_relocator_forward_start,
RELOCATOR_SIZEOF (_forward));
}
grub_err_t
grub_relocator32_boot (struct grub_relocator *rel,
struct grub_relocator32_state state)
{
grub_addr_t target;
void *src;
grub_err_t err;
grub_addr_t relst;
err = grub_relocator_alloc_chunk_align (rel, &src, &target, 0,
(0xffffffff - RELOCATOR_SIZEOF (32))
+ 1, RELOCATOR_SIZEOF (32), 16);
if (err)
return err;
grub_relocator32_eax = state.eax;
grub_relocator32_ebx = state.ebx;
grub_relocator32_ecx = state.ecx;
grub_relocator32_edx = state.edx;
grub_relocator32_eip = state.eip;
grub_relocator32_esp = state.esp;
grub_memmove (src, &grub_relocator32_start, RELOCATOR_SIZEOF (32));
err = grub_relocator_prepare_relocs (rel, target, &relst);
if (err)
return err;
asm volatile ("cli");
((void (*) (void)) relst) ();
/* Not reached. */
return GRUB_ERR_NONE;
}