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| /* ----------------------------------------------------------------------- *
| *
| * 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.
| *
| * ----------------------------------------------------------------------- */
|
| /*
| * The actual transition into protected mode
| */
|
| #include <asm/boot.h>
| #include <asm/processor-flags.h>
| #include <asm/segment.h>
| #include <linux/linkage.h>
|
| .text
| .code16
|
| /*
| * void protected_mode_jump(u32 entrypoint, u32 bootparams);
| */
| GLOBAL(protected_mode_jump)
| movl %edx, %esi # Pointer to boot_params table
|
| xorl %ebx, %ebx
| movw %cs, %bx
| shll $4, %ebx
| addl %ebx, 2f
| jmp 1f # Short jump to serialize on 386/486
| 1:
|
| movw $__BOOT_DS, %cx
| movw $__BOOT_TSS, %di
|
| movl %cr0, %edx
| orb $X86_CR0_PE, %dl # Protected mode
| movl %edx, %cr0
|
| # Transition to 32-bit mode
| .byte 0x66, 0xea # ljmpl opcode
| 2: .long in_pm32 # offset
| .word __BOOT_CS # segment
| ENDPROC(protected_mode_jump)
|
| .code32
| .section ".text32","ax"
| GLOBAL(in_pm32)
| # Set up data segments for flat 32-bit mode
| movl %ecx, %ds
| movl %ecx, %es
| movl %ecx, %fs
| movl %ecx, %gs
| movl %ecx, %ss
| # The 32-bit code sets up its own stack, but this way we do have
| # a valid stack if some debugging hack wants to use it.
| addl %ebx, %esp
|
| # Set up TR to make Intel VT happy
| ltr %di
|
| # Clear registers to allow for future extensions to the
| # 32-bit boot protocol
| xorl %ecx, %ecx
| xorl %edx, %edx
| xorl %ebx, %ebx
| xorl %ebp, %ebp
| xorl %edi, %edi
|
| # Set up LDTR to make Intel VT happy
| lldt %cx
|
| jmpl *%eax # Jump to the 32-bit entrypoint
| ENDPROC(in_pm32)
|
|
