/* -*-Asm-*- */ /* * GRUB -- GRand Unified Bootloader * Copyright (C) 2007,2008 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 . */ #include #include #include #include #include #include .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) . = data_start + 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 $0x200, %ecx addl %ecx, %esi movl $DATA_ADDR, %edi call LOCAL(move_memory) /* Check for multiboot signature. */ cmpl $MULTIBOOT_HEADER_MAGIC, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_DATA_END) jz 1f movl (ramdisk_image - start), %esi movl (ramdisk_size - start), %ecx movl $(DATA_ADDR - 0x200), %edi jmp 2f 1: movl %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_COMPRESSED_SIZE), %ecx addl $(GRUB_KERNEL_MACHINE_RAW_SIZE - 0x200), %ecx 2: call LOCAL(move_memory) movsbl %dh, %eax movl %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_DOS_PART) movsbl (reg_edx + 2 - start), %eax movl %eax, %ss:(DATA_ADDR + GRUB_KERNEL_MACHINE_INSTALL_BSD_PART) 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" . = _start + CODE_SECTORS * 512