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/*
* relocate_kernel.S - put the kernel image in place to boot
* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/linkage.h>
/*
* Must be relocatable PIC code callable as a C function, that once
* it starts can not use the previous processes stack.
*/
.globl relocate_new_kernel
relocate_new_kernel:
/* read the arguments and say goodbye to the stack */
movl 4(%esp), %ebx /* page_list */
movl 8(%esp), %ebp /* reboot_code_buffer */
movl 12(%esp), %edx /* start address */
movl 16(%esp), %ecx /* cpu_has_pae */
/* zero out flags, and disable interrupts */
pushl $0
popfl
/* set a new stack at the bottom of our page... */
lea 4096(%ebp), %esp
/* store the parameters back on the stack */
pushl %edx /* store the start address */
/* Set cr0 to a known state:
* 31 0 == Paging disabled
* 18 0 == Alignment check disabled
* 16 0 == Write protect disabled
* 3 0 == No task switch
* 2 0 == Don't do FP software emulation.
* 0 1 == Proctected mode enabled
*/
movl %cr0, %eax
andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax
orl $(1<<0), %eax
movl %eax, %cr0
/* clear cr4 if applicable */
testl %ecx, %ecx
jz 1f
/* Set cr4 to a known state:
* Setting everything to zero seems safe.
*/
movl %cr4, %eax
andl $0, %eax
movl %eax, %cr4
jmp 1f
1:
/* Flush the TLB (needed?) */
xorl %eax, %eax
movl %eax, %cr3
/* Do the copies */
movl %ebx, %ecx
jmp 1f
0: /* top, read another word from the indirection page */
movl (%ebx), %ecx
addl $4, %ebx
1:
testl $0x1, %ecx /* is it a destination page */
jz 2f
movl %ecx, %edi
andl $0xfffff000, %edi
jmp 0b
2:
testl $0x2, %ecx /* is it an indirection page */
jz 2f
movl %ecx, %ebx
andl $0xfffff000, %ebx
jmp 0b
2:
testl $0x4, %ecx /* is it the done indicator */
jz 2f
jmp 3f
2:
testl $0x8, %ecx /* is it the source indicator */
jz 0b /* Ignore it otherwise */
movl %ecx, %esi /* For every source page do a copy */
andl $0xfffff000, %esi
movl $1024, %ecx
rep ; movsl
jmp 0b
3:
/* To be certain of avoiding problems with self-modifying code
* I need to execute a serializing instruction here.
* So I flush the TLB, it's handy, and not processor dependent.
*/
xorl %eax, %eax
movl %eax, %cr3
/* set all of the registers to known values */
/* leave %esp alone */
xorl %eax, %eax
xorl %ebx, %ebx
xorl %ecx, %ecx
xorl %edx, %edx
xorl %esi, %esi
xorl %edi, %edi
xorl %ebp, %ebp
ret
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.long relocate_new_kernel_end - relocate_new_kernel
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