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/* ----------------------------------------------------------------------- *
*
* Copyright 2013 Intel Corporation; author: Matt Fleming
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston MA 02110-1301, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
#define CR0_PG_BIT 31
#define CR4_PAE_BIT 5
#define MSR_EFER 0xc0000080
.globl kernel_jump
.type kernel_jump,@function
.code64
kernel_jump:
cli
/* save the content of rsi (boot_param argument of kernel_jump function) */
mov %rsi, %rbx
call base_address
base_address:
pop %rsi
/* need to perform a long jump to update cs */
/* load absolute address of pm_code in jmp_address location */
lea (pm_code - base_address)(%rsi, 1), %rax
mov %eax, (jmp_address - base_address)(%rsi, 1)
ljmp *(jmp_address - base_address)(%rsi, 1)
jmp_address:
.long 0 /* address */
.word 0x10 /* segment */
.code32
pm_code:
/* cs segment has been updated, now update the rest */
mov $0x18, %eax
mov %eax, %ds
mov %eax, %es
mov %eax, %fs
mov %eax, %gs
mov %eax, %ss
/* disable paging. */
mov %cr0, %eax
btr $CR0_PG_BIT, %eax /* PG in CR0 */
mov %eax, %cr0
/* disable long mode. */
mov $MSR_EFER, %ecx
rdmsr
btr $8, %eax
wrmsr
/* kernel jump */
mov %ebx, %esi
jmp *%edi
.code64
.align 4
.globl efi_handover_32
.type efi_handover_32,@function
efi_handover_32:
movl $38, errno(%rip) /* ENOSYS */
ret
.globl efi_handover_64
.globl efi_handover
.type efi_handover_64,@function
.type efi_handover,@function
efi_handover_64:
efi_handover:
add $512, %rcx
cli
jmp *%rcx
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