coreboot-kgpe-d16/src/arch/x86/boot/gdt.c

61 lines
1.6 KiB
C

/*
* This file is part of the coreboot project.
*
* Copyright (C) 2008-2009 coresystems GmbH
*
* 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; version 2 of the License.
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <types.h>
#include <string.h>
#include <cbmem.h>
#include <lib.h>
#include <console/console.h>
// Global Descriptor Table, defined in c_start.S
extern char gdt;
extern char gdt_end;
/* i386 lgdt argument */
struct gdtarg {
u16 limit;
u32 base;
} __attribute__((packed));
// Copy GDT to new location and reload it
void move_gdt(void)
{
void *newgdt;
u16 num_gdt_bytes = &gdt_end - &gdt;
struct gdtarg gdtarg;
newgdt = cbmem_find(CBMEM_ID_GDT);
if (!newgdt) {
newgdt = cbmem_add(CBMEM_ID_GDT, ALIGN(num_gdt_bytes, 512));
if (!newgdt) {
printk(BIOS_ERR, "Error: Could not relocate GDT.\n");
return;
}
printk(BIOS_DEBUG, "Moving GDT to %p...", newgdt);
memcpy((void*)newgdt, &gdt, num_gdt_bytes);
}
gdtarg.base = (u32)newgdt;
gdtarg.limit = num_gdt_bytes - 1;
__asm__ __volatile__ ("lgdt %0\n\t" : : "m" (gdtarg));
printk(BIOS_DEBUG, "ok\n");
}