57 lines
1.3 KiB
ArmAsm
57 lines
1.3 KiB
ArmAsm
/* ----------------------------------------------------------------------- *
|
|
*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright 2007 rPath, Inc. - All Rights Reserved
|
|
*
|
|
* This file is part of the Linux kernel, and is made available under
|
|
* the terms of the GNU General Public License version 2.
|
|
*
|
|
* ----------------------------------------------------------------------- */
|
|
|
|
/*
|
|
* arch/i386/boot/pmjump.S
|
|
*
|
|
* The actual transition into protected mode
|
|
*/
|
|
|
|
#include <asm/boot.h>
|
|
#include <asm/segment.h>
|
|
|
|
.text
|
|
|
|
.globl protected_mode_jump
|
|
.type protected_mode_jump, @function
|
|
|
|
.code16
|
|
|
|
/*
|
|
* void protected_mode_jump(u32 entrypoint, u32 bootparams);
|
|
*/
|
|
protected_mode_jump:
|
|
movl %edx, %esi # Pointer to boot_params table
|
|
movl %eax, 2f # Patch ljmpl instruction
|
|
|
|
movw $__BOOT_DS, %cx
|
|
xorl %ebx, %ebx # Per the 32-bit boot protocol
|
|
xorl %ebp, %ebp # Per the 32-bit boot protocol
|
|
xorl %edi, %edi # Per the 32-bit boot protocol
|
|
|
|
movl %cr0, %edx
|
|
orb $1, %dl # Protected mode (PE) bit
|
|
movl %edx, %cr0
|
|
jmp 1f # Short jump to serialize on 386/486
|
|
1:
|
|
|
|
movw %cx, %ds
|
|
movw %cx, %es
|
|
movw %cx, %fs
|
|
movw %cx, %gs
|
|
movw %cx, %ss
|
|
|
|
# Jump to the 32-bit entrypoint
|
|
.byte 0x66, 0xea # ljmpl opcode
|
|
2: .long 0 # offset
|
|
.word __BOOT_CS # segment
|
|
|
|
.size protected_mode_jump, .-protected_mode_jump
|