diff options
Diffstat (limited to 'grub-core/boot/i386/pc/lnxboot.S')
| -rw-r--r-- | grub-core/boot/i386/pc/lnxboot.S | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/grub-core/boot/i386/pc/lnxboot.S b/grub-core/boot/i386/pc/lnxboot.S new file mode 100644 index 0000000..2dda0e0 --- /dev/null +++ b/grub-core/boot/i386/pc/lnxboot.S @@ -0,0 +1,295 @@ +/* -*-Asm-*- */ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2007,2008,2009 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/>. + */ + +#include <config.h> +#include <grub/symbol.h> +#include <grub/machine/boot.h> +#include <grub/machine/kernel.h> +#include <multiboot.h> + + .file "lnxboot.S" + +#define CODE_ADDR 0x6000 +#define CODE_SECTORS 1 +#define DATA_ADDR ((GRUB_BOOT_MACHINE_KERNEL_ADDR) + 0x200) + +#define BLCK_LENG 0x4000 + + .text + + .code16 + + .globl start, _start + +data_start: + xorl %ebp, %ebp + jmp LOCAL(linux_next) + + .org 0x1F1 + +setup_sects: + .byte CODE_SECTORS +root_flags: + .word 0 +syssize: + .word 0 +swap_dev: + .word 0 +ram_size: + .word 0 +vid_mode: + .word 0 +root_dev: + .word 0 +boot_flag: + .word 0xAA55 + +start: +_start: + + jmp LOCAL(linux_init) + + .ascii "HdrS" /* Header signature. */ + .word 0x0203 /* Header version number. */ + +realmode_swtch: + .word 0, 0 /* default_switch, SETUPSEG. */ +start_sys_seg: + .word 0x1000 /* Obsolete. */ +version_ptr: + .word 0 /* Version string ptr. */ +type_of_loader: + .byte 0 /* Filled in by boot loader. */ +loadflags: + .byte 1 /* Please load high. */ +setup_move_size: + .word 0 /* Unused. */ +code32_start: + .long 0x100000 /* 32-bit start address. */ +ramdisk_image: + .long 0 /* Loaded ramdisk image address. */ +ramdisk_size: + .long 0 /* Size of loaded ramdisk. */ +bootsect_kludge: + .word 0, 0 +heap_end_ptr: + .word 0 +pad1: + .word 0 +cmd_line_ptr: + .long 0 /* Command line. */ +ramdisk_max: + .long 0xffffffff /* Highest allowed ramdisk address. */ + +gdt: + .long 0, 0, 0, 0 /* Must be zero. */ + .word 0xffff /* 64 K segment size. */ +gdt_src1: + .byte 0, 0 ,0 /* Low 24 bits of source address. */ + .byte 0x93 /* Access rights. */ + .byte 0 /* Extended access rights. */ +gdt_src2: + .byte 0 /* High 8 bits of source address. */ + .word 0xffff /* 64 K segment size. */ +gdt_dst1: + .byte 0, 0, 0 /* Low 24 bits of target address. */ + .byte 0x93 /* Access rights. */ + .byte 0 /* Extended access rights. */ +gdt_dst2: + .byte 0 /* High 8 bits of source address. */ + .long 0, 0, 0, 0 /* More space for the BIOS. */ + +reg_edx: + .byte 0x80, 0, 0xFF, 0xFF + +data_leng: + .long 0 + +LOCAL(linux_init): + movw %cs:(reg_edx - start), %dx + movl %cs:(code32_start - start), %ebp + +LOCAL(linux_next): + + call LOCAL(normalize) + +LOCAL(normalize): + popw %bx + subw $(LOCAL(normalize) - start), %bx + shrw $4, %bx + movw %cs, %ax + addw %bx, %ax + pushw %ax + pushw $(real_code - start) + lret /* Jump to real_code. */ + +real_code: + subw $0x20, %ax + movw %ax, %ds + movw (setup_sects - data_start), %cx + shlw $7, %cx + + /* Setup stack. */ + + xorw %si, %si + movw %si, %ss + movw $(CODE_ADDR), %sp + + /* Move itself to 0:CODE_ADDR. */ + + cld + movw %cs, %ax + movw %ax, %ds + movw $(CODE_ADDR >> 4), %ax + movw %ax, %es + movw %si, %di + + rep + movsl + ljmp $(CODE_ADDR >> 4), $(real_code_2 - start) + +real_code_2: + + xchgl %ebp, %esi + orl %esi, %esi + jnz 1f + movw %ds, %si + shll $4, %esi + addl %ebp, %esi +1: + + pushw %es + popw %ds + + movl $0x1000, %ecx + addl $0x200, %esi + movl $DATA_ADDR, %edi + + call LOCAL(move_memory) + + /* Check for multiboot signature. */ + movl $DATA_ADDR, %edi +3: + movl %ss:(%edi), %eax + cmpl $MULTIBOOT_HEADER_MAGIC, %eax + jz 1f + addl $4, %edi + cmpl $(DATA_ADDR + 0x1000), %edi + jne 3b + + movl (ramdisk_image - start), %esi + movl (ramdisk_size - start), %ecx + movl $(DATA_ADDR - 0x200), %edi + jmp 2f + +1: + + movl $(DATA_ADDR + 0x1000), %edi + movl %ss:(DATA_ADDR + GRUB_DECOMPRESSOR_MACHINE_COMPRESSED_SIZE), %ecx + addl $GRUB_DECOMPRESSOR_I386_PC_MAX_DECOMPRESSOR_SIZE, %ecx + +2: + call LOCAL(move_memory) + + movb %dh, %ss:(DATA_ADDR + GRUB_DECOMPRESSOR_I386_PC_BOOT_DEVICE + 2) + movb (reg_edx + 2 - start), %dh + movb %dh, %ss:(DATA_ADDR + GRUB_DECOMPRESSOR_I386_PC_BOOT_DEVICE + 1) + + movb $0xFF, %dh + + ljmp $(DATA_ADDR >> 4), $0 + +/* + * Parameters: + * esi: source address + * edi: target address + * ecx: number of bytes + */ + +LOCAL(move_memory): + incl %ecx + andb $0xFE, %cl + pushw %dx +1: + pushl %esi + pushl %edi + pushl %ecx + cmpl $BLCK_LENG, %ecx + jbe 2f + movl $BLCK_LENG, %ecx +2: + pushl %ecx + + movl %esi, %eax + movw %si, (gdt_src1 - start) + shrl $16, %eax + movb %al, (gdt_src1 + 2 - start) + movb %ah, (gdt_src2 - start) + + movl %edi, %eax + movw %di, (gdt_dst1 - start) + shrl $16, %eax + movb %al, (gdt_dst1 + 2 - start) + movb %ah, (gdt_dst2 - start) + + movw $(gdt - start), %si + movb $0x87, %ah + shrw $1, %cx + + int $0x15 + + popl %eax + popl %ecx + popl %edi + popl %esi + + jnc 2f + movw $(err_int15_msg - start), %si + jmp LOCAL(fail) + +2: + + addl %eax, %esi + addl %eax, %edi + subl %eax, %ecx + jnz 1b + + + popw %dx + ret + +/* + * Parameters: + * si: message + */ + +LOCAL(fail): + movb $0x0e, %ah + xorw %bx, %bx +1: + lodsb (%si), %al + int $0x10 + cmpb $0, %al + jne 1b +1: jmp 1b + +err_int15_msg: + .ascii "move memory fails\0" + + .org (CODE_SECTORS * 512 + 512) |