diff options
Diffstat (limited to 'grub-core/lib/i386/relocator32.S')
| -rw-r--r-- | grub-core/lib/i386/relocator32.S | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/grub-core/lib/i386/relocator32.S b/grub-core/lib/i386/relocator32.S new file mode 100644 index 0000000..09ce56a --- /dev/null +++ b/grub-core/lib/i386/relocator32.S @@ -0,0 +1,134 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2009,2010 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/>. + */ + +/* The code segment of the protected mode. */ +#define CODE_SEGMENT 0x10 + +/* The data segment of the protected mode. */ +#define DATA_SEGMENT 0x18 + +#include "relocator_common.S" + + .p2align 4 /* force 16-byte alignment */ + +VARIABLE(grub_relocator32_start) + PREAMBLE + + RELOAD_GDT + .code32 + /* Update other registers. */ + movl $DATA_SEGMENT, %eax + movl %eax, %ds + movl %eax, %es + movl %eax, %fs + movl %eax, %gs + movl %eax, %ss + + DISABLE_PAGING + +#ifdef __x86_64__ + /* Disable amd64. */ + movl $GRUB_MEMORY_CPU_AMD64_MSR, %ecx + rdmsr + andl $(~GRUB_MEMORY_CPU_AMD64_MSR_ON), %eax + wrmsr +#endif + + /* Turn off PAE. */ + movl %cr4, %eax + andl $(~GRUB_MEMORY_CPU_CR4_PAE_ON), %eax + movl %eax, %cr4 + + jmp LOCAL(cont2) +LOCAL(cont2): + .code32 + + /* mov imm32, %eax */ + .byte 0xb8 +VARIABLE(grub_relocator32_esp) + .long 0 + + movl %eax, %esp + + /* mov imm32, %eax */ + .byte 0xb8 +VARIABLE(grub_relocator32_ebp) + .long 0 + + movl %eax, %ebp + + /* mov imm32, %eax */ + .byte 0xb8 +VARIABLE(grub_relocator32_esi) + .long 0 + + movl %eax, %esi + + /* mov imm32, %eax */ + .byte 0xb8 +VARIABLE(grub_relocator32_edi) + .long 0 + + movl %eax, %edi + + /* mov imm32, %eax */ + .byte 0xb8 +VARIABLE(grub_relocator32_eax) + .long 0 + + /* mov imm32, %ebx */ + .byte 0xbb +VARIABLE(grub_relocator32_ebx) + .long 0 + + /* mov imm32, %ecx */ + .byte 0xb9 +VARIABLE(grub_relocator32_ecx) + .long 0 + + /* mov imm32, %edx */ + .byte 0xba +VARIABLE(grub_relocator32_edx) + .long 0 + + /* Cleared direction flag is of no problem with any current + payload and makes this implementation easier. */ + cld + + .byte 0xea +VARIABLE(grub_relocator32_eip) + .long 0 + .word CODE_SEGMENT + + /* GDT. Copied from loader/i386/linux.c. */ + .p2align 4 +LOCAL(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 +LOCAL(gdt_end): + +VARIABLE(grub_relocator32_end) |