88 lines
2.1 KiB
ArmAsm
88 lines
2.1 KiB
ArmAsm
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/* startup.S - bootstrap GRUB itself */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2006,2007 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <grub/symbol.h>
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#include <grub/boot.h>
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.file "startup.S"
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.text
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.globl start, _start
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.code64
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start:
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_start:
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jmp codestart
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/*
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* Compatibility version number
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*
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* These MUST be at byte offset 6 and 7 of the executable
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* DO NOT MOVE !!!
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*/
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. = EXT_C(start) + 0x6
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.byte GRUB_BOOT_VERSION_MAJOR, GRUB_BOOT_VERSION_MINOR
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/*
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* This is a special data area 8 bytes from the beginning.
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*/
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. = EXT_C(start) + 0x8
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VARIABLE(grub_prefix)
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/* to be filled by grub-mkimage */
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/*
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* Leave some breathing room for the prefix.
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*/
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. = EXT_C(start) + 0x50
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codestart:
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movq %rcx, EXT_C(grub_efi_image_handle)
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movq %rdx, EXT_C(grub_efi_system_table)
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call EXT_C(grub_main)
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ret
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.code32
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FUNCTION(grub_linux_real_boot)
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/* Turn off PG bit in CR0 and set CR3 to zero. */
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movl %cr0, %eax
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andl $0x7FFFFFFF, %eax
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movl %eax, %cr0
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/* Setup EFER (Extended Feature Enable Register). */
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movl $0xc0000080, %ecx
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rdmsr
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/* Disable Long Mode. */
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andl $0xFFFFFEFF, %eax
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/* Make changes effective. */
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wrmsr
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/* Disable PAE. */
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xorl %eax, %eax
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movl %eax, %cr4
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jmp *%ebx
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