diff options
Diffstat (limited to 'src/arch/x86/gdt_init.S')
| -rw-r--r-- | src/arch/x86/gdt_init.S | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/src/arch/x86/gdt_init.S b/src/arch/x86/gdt_init.S new file mode 100644 index 0000000000..6aa2a79b48 --- /dev/null +++ b/src/arch/x86/gdt_init.S @@ -0,0 +1,43 @@ +/* + * This file is part of the coreboot project. + * + * 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. + */ +.code32 +.section ".text._gdt_", "ax", @progbits + + .globl gdt_init +gdt_init: + lgdt %cs:gdtptr + ret + +.previous + .align 4 +.globl gdtptr +gdt: +gdtptr: + .word gdt_end - gdt -1 /* compute the table limit */ + .long gdt /* we know the offset */ + .word 0 + + /* selgdt 0x08, flat code segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x9b, 0xcf, 0x00 /* G=1 and 0x0f, So we get 4Gbytes + for limit */ + + /* selgdt 0x10,flat data segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x93, 0xcf, 0x00 + + /* selgdt 0x18, flat code segment (64-bit) */ + .word 0xffff, 0x0000 + .byte 0x00, 0x9b, 0xaf, 0x00 + +gdt_end: |