| /* |
| * GRUB -- GRand Unified Bootloader |
| * Copyright (C) 2009 Free Software Foundation, Inc. |
| * |
| * GRUB 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, either version 3 of the License, or |
| * (at your option) any later version. |
| * |
| * GRUB is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with GRUB. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| |
| .p2align 4 /* force 16-byte alignment */ |
| .globl trampoline |
| trampoline: |
| cli |
| /* %rdi contains protected memory start and %rsi |
| contains real memory start. */ |
| |
| mov %rsi, %rbx |
| |
| call base |
| base: |
| pop %rsi |
| |
| lea (cont1 - base) (%rsi, 1), %rax |
| mov %eax, (jump_vector - base) (%rsi, 1) |
| |
| lea (gdt - base) (%rsi, 1), %rax |
| mov %rax, (gdtaddr - base) (%rsi, 1) |
| |
| /* Switch to compatibility mode. */ |
| |
| lidt (idtdesc - base) (%rsi, 1) |
| lgdt (gdtdesc - base) (%rsi, 1) |
| |
| /* Update %cs. Thanks to David Miller for pointing this mistake out. */ |
| ljmp *(jump_vector - base) (%rsi, 1) |
| |
| cont1: |
| .code32 |
| |
| /* Update other registers. */ |
| mov $0x18, %eax |
| mov %eax, %ds |
| mov %eax, %es |
| mov %eax, %fs |
| mov %eax, %gs |
| mov %eax, %ss |
| |
| /* Disable paging. */ |
| mov %cr0, %eax |
| and $0x7fffffff, %eax |
| mov %eax, %cr0 |
| |
| /* Disable amd64. */ |
| mov $0xc0000080, %ecx |
| rdmsr |
| and $0xfffffeff, %eax |
| wrmsr |
| |
| /* Turn off PAE. */ |
| movl %cr4, %eax |
| and $0xffffffcf, %eax |
| mov %eax, %cr4 |
| |
| jmp cont2 |
| cont2: |
| .code32 |
| |
| mov %ebx, %esi |
| |
| jmp *%edi |
| |
| /* GDT. */ |
| .p2align 4 |
| gdt: |
| /* NULL. */ |
| .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 |
| |
| /* Reserved. */ |
| .byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 |
| |
| /* Code segment. */ |
| .byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9A, 0xCF, 0x00 |
| |
| /* Data segment. */ |
| .byte 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x92, 0xCF, 0x00 |
| |
| gdtdesc: |
| .word 31 |
| gdtaddr: |
| .quad gdt |
| |
| idtdesc: |
| .word 0 |
| idtaddr: |
| .quad 0 |
| |
| .p2align 4 |
| jump_vector: |
| /* Jump location. Is filled by the code */ |
| .long 0 |
| .long 0x10 |
| |