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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>
/*
* 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
.code64
relocate_new_kernel:
/* %rdi page_list
* %rsi reboot_code_buffer
* %rdx start address
* %rcx page_table
* %r8 arg5
* %r9 arg6
*/
/* zero out flags, and disable interrupts */
pushq $0
popfq
/* set a new stack at the bottom of our page... */
lea 4096(%rsi), %rsp
/* store the parameters back on the stack */
pushq %rdx /* store the start address */
/* Set cr0 to a known state:
* 31 1 == Paging enabled
* 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
*/
movq %cr0, %rax
andq $~((1<<18)|(1<<16)|(1<<3)|(1<<2)), %rax
orl $((1<<31)|(1<<0)), %eax
movq %rax, %cr0
/* Set cr4 to a known state:
* 10 0 == xmm exceptions disabled
* 9 0 == xmm registers instructions disabled
* 8 0 == performance monitoring counter disabled
* 7 0 == page global disabled
* 6 0 == machine check exceptions disabled
* 5 1 == physical address extension enabled
* 4 0 == page size extensions disabled
* 3 0 == Debug extensions disabled
* 2 0 == Time stamp disable (disabled)
* 1 0 == Protected mode virtual interrupts disabled
* 0 0 == VME disabled
*/
movq $((1<<5)), %rax
movq %rax, %cr4
jmp 1f
1:
/* Switch to the identity mapped page tables,
* and flush the TLB.
*/
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
relocate_new_kernel_end:
.globl relocate_new_kernel_size
relocate_new_kernel_size:
.quad relocate_new_kernel_end - relocate_new_kernel
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