mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-18 18:59:44 +00:00
90ab311a7c
You can directly specify the label as the operand for ljmp. This commit saves 4-byte code. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Tested-by: Bin Meng <bmeng.cn@gmail.com> [bmeng: fixed the gas warning] Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
123 lines
2.8 KiB
ArmAsm
123 lines
2.8 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0+ */
|
|
/*
|
|
* U-Boot - x86 Startup Code
|
|
*
|
|
* (C) Copyright 2008-2011
|
|
* Graeme Russ, <graeme.russ@gmail.com>
|
|
*
|
|
* (C) Copyright 2002,2003
|
|
* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
|
|
*/
|
|
|
|
#include <asm/global_data.h>
|
|
#include <asm/processor-flags.h>
|
|
|
|
#define BOOT_SEG 0xffff0000 /* linear segment of boot code */
|
|
|
|
.section .start16, "ax"
|
|
.code16
|
|
.globl start16
|
|
start16:
|
|
/* Save BIST */
|
|
movl %eax, %ecx
|
|
|
|
xorl %eax, %eax
|
|
movl %eax, %cr3 /* Invalidate TLB */
|
|
|
|
/* Turn off cache (this might require a 486-class CPU) */
|
|
movl %cr0, %eax
|
|
orl $(X86_CR0_NW | X86_CR0_CD), %eax
|
|
movl %eax, %cr0
|
|
wbinvd
|
|
|
|
/* load the temporary Global Descriptor Table */
|
|
data32 cs lidt idt_ptr
|
|
data32 cs lgdt gdt_ptr
|
|
|
|
/* Now, we enter protected mode */
|
|
movl %cr0, %eax
|
|
orl $X86_CR0_PE, %eax
|
|
movl %eax, %cr0
|
|
|
|
/* Flush the prefetch queue */
|
|
jmp ff
|
|
ff:
|
|
|
|
/* Finally restore BIST and jump to the 32-bit initialization code */
|
|
movl %ecx, %eax
|
|
data32 cs ljmp *code32start
|
|
|
|
/* 48-bit far pointer */
|
|
code32start:
|
|
.long _start /* offset */
|
|
.word 0x10 /* segment */
|
|
|
|
idt_ptr:
|
|
.word 0 /* limit */
|
|
.long 0 /* base */
|
|
|
|
/*
|
|
* The following Global Descriptor Table is just enough to get us into
|
|
* 'Flat Protected Mode' - It will be discarded as soon as the final
|
|
* GDT is setup in a safe location in RAM
|
|
*/
|
|
gdt_ptr:
|
|
.word 0x1f /* limit (31 bytes = 4 GDT entries - 1) */
|
|
.long BOOT_SEG + gdt_rom /* base */
|
|
|
|
/* Some CPUs are picky about GDT alignment... */
|
|
.align 16
|
|
.globl gdt_rom
|
|
gdt_rom:
|
|
/*
|
|
* The GDT table ...
|
|
*
|
|
* Selector Type
|
|
* 0x00 NULL
|
|
* 0x08 Unused
|
|
* 0x10 32bit code
|
|
* 0x18 32bit data/stack
|
|
*/
|
|
/* The NULL Desciptor - Mandatory */
|
|
.word 0x0000 /* limit_low */
|
|
.word 0x0000 /* base_low */
|
|
.byte 0x00 /* base_middle */
|
|
.byte 0x00 /* access */
|
|
.byte 0x00 /* flags + limit_high */
|
|
.byte 0x00 /* base_high */
|
|
|
|
/* Unused Desciptor - (matches Linux) */
|
|
.word 0x0000 /* limit_low */
|
|
.word 0x0000 /* base_low */
|
|
.byte 0x00 /* base_middle */
|
|
.byte 0x00 /* access */
|
|
.byte 0x00 /* flags + limit_high */
|
|
.byte 0x00 /* base_high */
|
|
|
|
/*
|
|
* The Code Segment Descriptor:
|
|
* - Base = 0x00000000
|
|
* - Size = 4GB
|
|
* - Access = Present, Ring 0, Exec (Code), Readable
|
|
* - Flags = 4kB Granularity, 32-bit
|
|
*/
|
|
.word 0xffff /* limit_low */
|
|
.word 0x0000 /* base_low */
|
|
.byte 0x00 /* base_middle */
|
|
.byte 0x9b /* access */
|
|
.byte 0xcf /* flags + limit_high */
|
|
.byte 0x00 /* base_high */
|
|
|
|
/*
|
|
* The Data Segment Descriptor:
|
|
* - Base = 0x00000000
|
|
* - Size = 4GB
|
|
* - Access = Present, Ring 0, Non-Exec (Data), Writable
|
|
* - Flags = 4kB Granularity, 32-bit
|
|
*/
|
|
.word 0xffff /* limit_low */
|
|
.word 0x0000 /* base_low */
|
|
.byte 0x00 /* base_middle */
|
|
.byte 0x93 /* access */
|
|
.byte 0xcf /* flags + limit_high */
|
|
.byte 0x00 /* base_high */
|