112 lines
2.3 KiB
ArmAsm
112 lines
2.3 KiB
ArmAsm
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2009 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 <grub/symbol.h>
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.p2align 4 /* force 16-byte alignment */
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VARIABLE(grub_linux_trampoline_start)
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cli
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/* %rdi contains protected memory start and %rsi
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contains real memory start. */
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mov %rsi, %rbx
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call base
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base:
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pop %rsi
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lea (cont1 - base) (%rsi, 1), %rax
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mov %eax, (jump_vector - base) (%rsi, 1)
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lea (gdt - base) (%rsi, 1), %rax
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mov %rax, (gdtaddr - base) (%rsi, 1)
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/* Switch to compatibility mode. */
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lidt (idtdesc - base) (%rsi, 1)
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lgdt (gdtdesc - base) (%rsi, 1)
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/* Update %cs. Thanks to David Miller for pointing this mistake out. */
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ljmp *(jump_vector - base) (%rsi, 1)
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cont1:
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.code32
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/* Update other registers. */
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mov $0x18, %eax
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mov %eax, %ds
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mov %eax, %es
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mov %eax, %fs
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mov %eax, %gs
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mov %eax, %ss
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/* Disable paging. */
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mov %cr0, %eax
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and $0x7fffffff, %eax
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mov %eax, %cr0
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/* Disable amd64. */
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mov $0xc0000080, %ecx
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rdmsr
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and $0xfffffeff, %eax
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wrmsr
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/* Turn off PAE. */
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movl %cr4, %eax
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and $0xffffffcf, %eax
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mov %eax, %cr4
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jmp cont2
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cont2:
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.code32
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mov %ebx, %esi
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jmp *%edi
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/* GDT. */
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.p2align 4
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gdt:
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/* NULL. */
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.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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/* Reserved. */
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.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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/* Code segment. */
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.byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9A, 0xCF, 0x00
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/* Data segment. */
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.byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x92, 0xCF, 0x00
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gdtdesc:
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.word 31
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gdtaddr:
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.quad gdt
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idtdesc:
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.word 0
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idtaddr:
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.quad 0
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.p2align 4
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jump_vector:
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/* Jump location. Is filled by the code */
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.long 0
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.long 0x10
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VARIABLE(grub_linux_trampoline_end)
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