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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>
#include <asm/page.h>
#include <asm/kexec.h>
#include <asm/processor-flags.h>
/*
* Must be relocatable PIC code callable as a C function
*/
#define PTR(x) (x << 2)
#define PAGE_ATTR 0x63 /* _PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY */
#define PAE_PGD_ATTR 0x01 /* _PAGE_PRESENT */
.text
.align PAGE_SIZE
.globl relocate_kernel
relocate_kernel:
movl 8(%esp), %ebp /* list of pages */
#ifdef CONFIG_X86_PAE
/* map the control page at its virtual address */
movl PTR(VA_PGD)(%ebp), %edi
movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
andl $0xc0000000, %eax
shrl $27, %eax
addl %edi, %eax
movl PTR(PA_PMD_0)(%ebp), %edx
orl $PAE_PGD_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PMD_0)(%ebp), %edi
movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
andl $0x3fe00000, %eax
shrl $18, %eax
addl %edi, %eax
movl PTR(PA_PTE_0)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PTE_0)(%ebp), %edi
movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
andl $0x001ff000, %eax
shrl $9, %eax
addl %edi, %eax
movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
/* identity map the control page at its physical address */
movl PTR(VA_PGD)(%ebp), %edi
movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
andl $0xc0000000, %eax
shrl $27, %eax
addl %edi, %eax
movl PTR(PA_PMD_1)(%ebp), %edx
orl $PAE_PGD_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PMD_1)(%ebp), %edi
movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
andl $0x3fe00000, %eax
shrl $18, %eax
addl %edi, %eax
movl PTR(PA_PTE_1)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PTE_1)(%ebp), %edi
movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
andl $0x001ff000, %eax
shrl $9, %eax
addl %edi, %eax
movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
#else
/* map the control page at its virtual address */
movl PTR(VA_PGD)(%ebp), %edi
movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
andl $0xffc00000, %eax
shrl $20, %eax
addl %edi, %eax
movl PTR(PA_PTE_0)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PTE_0)(%ebp), %edi
movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
andl $0x003ff000, %eax
shrl $10, %eax
addl %edi, %eax
movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
/* identity map the control page at its physical address */
movl PTR(VA_PGD)(%ebp), %edi
movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
andl $0xffc00000, %eax
shrl $20, %eax
addl %edi, %eax
movl PTR(PA_PTE_1)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
movl PTR(VA_PTE_1)(%ebp), %edi
movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
andl $0x003ff000, %eax
shrl $10, %eax
addl %edi, %eax
movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
orl $PAGE_ATTR, %edx
movl %edx, (%eax)
#endif
relocate_new_kernel:
/* read the arguments and say goodbye to the stack */
movl 4(%esp), %ebx /* page_list */
movl 8(%esp), %ebp /* list of pages */
movl 12(%esp), %edx /* start address */
movl 16(%esp), %ecx /* cpu_has_pae */
/* zero out flags, and disable interrupts */
pushl $0
popfl
/* get physical address of control page now */
/* this is impossible after page table switch */
movl PTR(PA_CONTROL_PAGE)(%ebp), %edi
/* switch to new set of page tables */
movl PTR(PA_PGD)(%ebp), %eax
movl %eax, %cr3
/* setup a new stack at the end of the physical control page */
lea PAGE_SIZE(%edi), %esp
/* jump to identity mapped page */
movl %edi, %eax
addl $(identity_mapped - relocate_kernel), %eax
pushl %eax
ret
identity_mapped:
/* store the start address on the stack */
pushl %edx
/* Set cr0 to a known state:
* - Paging disabled
* - Alignment check disabled
* - Write protect disabled
* - No task switch
* - Don't do FP software emulation.
* - Proctected mode enabled
*/
movl %cr0, %eax
andl $~(X86_CR0_PG | X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %eax
orl $(X86_CR0_PE), %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.
*/
xorl %eax, %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
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