diff options
Diffstat (limited to 'arch/x86/lib/gdt.c')
-rw-r--r-- | arch/x86/lib/gdt.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/x86/lib/gdt.c b/arch/x86/lib/gdt.c new file mode 100644 index 0000000000..a9c4d0e9dd --- /dev/null +++ b/arch/x86/lib/gdt.c @@ -0,0 +1,55 @@ +/* + * Copyright (C) 2009 Juergen Beisert, Pengutronix + * + * 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 (at your option) 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., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + */ + +/** + * @file + * @brief Definition of the Global Descriptor Table + */ + +#include <types.h> +#include <asm/modes.h> +#include <asm/segment.h> + +/** + * The 'Global Descriptor Table' used in barebox + * + * Note: This table must reachable by real and flat mode code + */ +uint64_t gdt[] __attribute__((aligned(16))) __bootdata = { + /* CS: code, read/execute, 4 GB, base 0 */ + [GDT_ENTRY_BOOT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff), + /* DS: data, read/write, 4 GB, base 0 */ + [GDT_ENTRY_BOOT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff), + /* CS: for real mode calls */ + [GDT_ENTRY_REAL_CS] = GDT_ENTRY(0x009E, 0, 0x0ffff), + /* DS: for real mode calls */ + [GDT_ENTRY_REAL_DS] = GDT_ENTRY(0x0092, 0, 0x0ffff), + /* TSS: 32-bit tss, 104 bytes, base 4096 */ + /* We only have a TSS here to keep Intel VT happy; + we don't actually use it for anything. */ + [GDT_ENTRY_BOOT_TSS] = GDT_ENTRY(0x0089, 4096, 103), +}; + +/** + * Size of the GDT must be known to load it + * + * Note: This varibale must reachable by real and flat mode code + */ +unsigned gdt_size __bootdata = sizeof(gdt); |