/* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 2 of the
* License, or 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <realmode.h>
#include <biosint.h>
#include <gpxe/hidemem.h>
/* Linker-defined symbols */
extern char _text[];
extern char _end[];
/** Assembly routine in e820mangler.S */
extern void int15();
/** Vector for storing original INT 15 handler */
extern struct segoff __text16 ( int15_vector );
#define int15_vector __use_text16 ( int15_vector )
/**
* List of hidden regions
*
* Must be terminated by a zero entry.
*/
struct hidden_region __data16_array ( hidden_regions, [] ) = {
[TEXT] = { 0, 0 },
[BASEMEM] = { 0, ( 640 * 1024 ) },
[EXTMEM] = { 0, 0 },
{ 0, 0, } /* Terminator */
};
/**
* Hide Etherboot
*
* Installs an INT 15 handler to edit Etherboot out of the memory map
* returned by the BIOS.
*/
void hide_etherboot ( void ) {
hidden_regions[TEXT].start = virt_to_phys ( _text );
hidden_regions[TEXT].end = virt_to_phys ( _end );
hidden_regions[BASEMEM].start = ( rm_cs << 4 );
DBG ( "Hiding [%lx,%lx) and [%lx,%lx)\n",
( unsigned long ) hidden_regions[TEXT].start,
( unsigned long ) hidden_regions[TEXT].end,
( unsigned long ) hidden_regions[BASEMEM].start,
( unsigned long ) hidden_regions[BASEMEM].end );
hook_bios_interrupt ( 0x15, ( unsigned int ) int15,
&int15_vector );
}
/**
* Unhide Etherboot
*
* Uninstalls the INT 15 handler installed by hide_etherboot(), if
* possible.
*/
void unhide_etherboot ( void ) {
unhook_bios_interrupt ( 0x15, ( unsigned int ) int15,
&int15_vector );
}
