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/*
* relocate_kernel.S - put the kernel image in place to boot
* Copyright (C) 2002-2005 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_types.h>
#include <asm/kexec.h>
#include <asm/processor-flags.h>
#include <asm/pgtable_types.h>
/*
* Must be relocatable PIC code callable as a C function
*/
#define PTR(x) (x << 3)
#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
.text
.align PAGE_SIZE
.code64
.globl relocate_kernel
relocate_kernel:
/*
* %rdi indirection_page
* %rsi page_list
* %rdx start address
*/
/* zero out flags, and disable interrupts */
pushq $0
popfq
/*
* get physical address of control page now
* this is impossible after page table switch
*/
movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
/* get physical address of page table now too */
movq PTR(PA_TABLE_PAGE)(%rsi), %rcx
/* Switch to the identity mapped page tables */
movq %rcx, %cr3
/* setup a new stack at the end of the physical control page */
lea PAGE_SIZE(%r8), %rsp
/* jump to identity mapped page */
addq $(identity_mapped - relocate_kernel), %r8
pushq %r8
ret
identity_mapped:
/* store the start address on the stack */
pushq %rdx
/*
* Set cr0 to a known state:
* - Paging enabled
* - Alignment check disabled
* - Write protect disabled
* - No task switch
* - Don't do FP software emulation.
* - Proctected mode enabled
*/
movq %cr0, %rax
andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax
orl $(X86_CR0_PG | X86_CR0_PE), %eax
movq %rax, %cr0
/*
* Set cr4 to a known state:
* - physical address extension enabled
*/
movq $X86_CR4_PAE, %rax
movq %rax, %cr4
jmp 1f
1:
/* Flush the TLB (needed?) */
movq %rcx, %cr3
/* Do the copies */
movq %rdi, %rcx /* Put the page_list in %rcx */
xorq %rdi, %rdi
xorq %rsi, %rsi
jmp 1f
0: /* top, read another word for the indirection page */
movq (%rbx), %rcx
addq $8, %rbx
1:
testq $0x1, %rcx /* is it a destination page? */
jz 2f
movq %rcx, %rdi
andq $0xfffffffffffff000, %rdi
jmp 0b
2:
testq $0x2, %rcx /* is it an indirection page? */
jz 2f
movq %rcx, %rbx
andq $0xfffffffffffff000, %rbx
jmp 0b
2:
testq $0x4, %rcx /* is it the done indicator? */
jz 2f
jmp 3f
2:
testq $0x8, %rcx /* is it the source indicator? */
jz 0b /* Ignore it otherwise */
movq %rcx, %rsi /* For ever source page do a copy */
andq $0xfffffffffffff000, %rsi
movq $512, %rcx
rep ; movsq
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 by reloading %cr3 here, it's handy,
* and not processor dependent.
*/
movq %cr3, %rax
movq %rax, %cr3
/*
* set all of the registers to known values
* leave %rsp alone
*/
xorq %rax, %rax
xorq %rbx, %rbx
xorq %rcx, %rcx
xorq %rdx, %rdx
xorq %rsi, %rsi
xorq %rdi, %rdi
xorq %rbp, %rbp
xorq %r8, %r8
xorq %r9, %r9
xorq %r10, %r9
xorq %r11, %r11
xorq %r12, %r12
xorq %r13, %r13
xorq %r14, %r14
xorq %r15, %r15
ret
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