coreboot-kgpe-d16/src/arch/x86/assembly_entry.S
Hannah Williams d3c0c0c318 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>
2018-05-03 04:40:58 +00:00

90 lines
2.4 KiB
ArmAsm

/*
* This file is part of the coreboot project.
*
* Copyright 2016 Google Inc.
* Copyright (C) 2016 Intel Corp.
*
* 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.
*/
#include <rules.h>
#if IS_ENABLED(CONFIG_C_ENVIRONMENT_BOOTBLOCK)
/*
* This path is for stages that are post bootblock when employing
* CONFIG_C_ENVIRONMENT_BOOTBLOCK. The gdt is reloaded to accommodate
* platforms that are executing out of CAR. In order to continue with
* C code execution one needs to set stack pointer and clear CAR_GLOBAL
* variables that are stage specific.
*/
.section ".text._start", "ax", @progbits
.global _start
_start:
/* Migrate GDT to this text segment */
call gdt_init
/* reset stack pointer to CAR stack */
mov $_car_stack_end, %esp
/* clear CAR_GLOBAL area as it is not shared */
cld
xor %eax, %eax
movl $(_car_global_end), %ecx
movl $(_car_global_start), %edi
sub %edi, %ecx
rep stosl
#if ((ENV_VERSTAGE && IS_ENABLED(CONFIG_VERSTAGE_DEBUG_SPINLOOP)) \
|| (ENV_ROMSTAGE && IS_ENABLED(CONFIG_ROMSTAGE_DEBUG_SPINLOOP)))
/* Wait for a JTAG debugger to break in and set EBX non-zero */
xor %ebx, %ebx
debug_spinloop:
cmp $0, %ebx
jz debug_spinloop
#endif
andl $0xfffffff0, %esp
#if IS_ENABLED(CONFIG_IDT_IN_EVERY_STAGE)
call exception_init
#endif
call car_stage_entry
/* This is here for linking purposes. */
.weak car_stage_entry
car_stage_entry:
1:
jmp 1b
#else
/* This file assembles the start of the romstage program by the order of the
* includes. Thus, it's extremely important that one pays very careful
* attention to the order of the includes. */
#include <arch/x86/prologue.inc>
#include <cpu/x86/32bit/entry32.inc>
#include <cpu/x86/fpu_enable.inc>
#if IS_ENABLED(CONFIG_SSE)
#include <cpu/x86/sse_enable.inc>
#endif
/*
* The assembly.inc is generated based on the requirements of the mainboard.
* For example, for ROMCC boards the MAINBOARDDIR/romstage.c would be
* processed by ROMCC and added. In non-ROMCC boards the chipsets'
* cache-as-ram setup files would be here.
*/
#include <generated/assembly.inc>
#endif