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coreboot-kgpe-d16/src/arch/x86/gdt_init.S

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arch/x86: Relocate GDT in verstage, romstage, and postcar In each stage keep GDT in the code region. This accommodates platforms, such as glk, that are executing out of CAR. The gdt is small and loading it is trivial so just do it unconditionally instead of introducing another Kconfig. BUG=b:78656686 Change-Id: I01ded6e9b358b23e04d92bef5263bfe8c2a5ec5a Signed-off-by: Hannah Williams <hannah.williams@intel.com> Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/25895 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Justin TerAvest <teravest@chromium.org>
2018-04-27 18:09:04 +02:00
/*
* 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
gdtptr:
.word gdt_end - gdt -1 /* compute the table limit */
.long gdt /* we know the offset */
arch/x86: Prepare GDT for x86_64 Make GDT a separate table and don't reuse GDT descriptor as unused first field of GDT. Required for separate x86_64 GDT descriptor, pointing to the same GDT. Tested on qemu. Change-Id: I513329b67d49ade1055bc07cf7b93ff2e0131e0b Signed-off-by: Patrick Rudolph <siro@das-labor.org> Reviewed-on: https://review.coreboot.org/c/coreboot/+/31769 Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com> Reviewed-by: Patrick Georgi <pgeorgi@google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2019-03-03 17:58:54 +01:00
.align 4
gdt:
/* selgdt 0, unused */
.word 0x0000, 0x0000 /* dummy */
.byte 0x00, 0x00, 0x00, 0x00
arch/x86: Relocate GDT in verstage, romstage, and postcar In each stage keep GDT in the code region. This accommodates platforms, such as glk, that are executing out of CAR. The gdt is small and loading it is trivial so just do it unconditionally instead of introducing another Kconfig. BUG=b:78656686 Change-Id: I01ded6e9b358b23e04d92bef5263bfe8c2a5ec5a Signed-off-by: Hannah Williams <hannah.williams@intel.com> Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/25895 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Justin TerAvest <teravest@chromium.org>
2018-04-27 18:09:04 +02:00
/* 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: