352 lines
7.3 KiB
ArmAsm
352 lines
7.3 KiB
ArmAsm
/*
|
|
* GRUB -- GRand Unified Bootloader
|
|
* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007,2008,2009,2011 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/offsets.h>
|
|
#include <grub/machine/boot.h>
|
|
#include <grub/machine/memory.h>
|
|
#include <grub/machine/kernel.h>
|
|
|
|
#define ABS(x) ((x) - LOCAL (base) + GRUB_BOOT_MACHINE_KERNEL_ADDR + 0x200)
|
|
|
|
.file "startup_raw.S"
|
|
|
|
.text
|
|
|
|
/* Tell GAS to generate 16-bit instructions so that this code works
|
|
in real mode. */
|
|
.code16
|
|
|
|
.globl start, _start
|
|
start:
|
|
_start:
|
|
LOCAL (base):
|
|
/*
|
|
* Guarantee that "main" is loaded at 0x0:0x8200.
|
|
*/
|
|
#ifdef __APPLE__
|
|
ljmp $0, $(ABS(LOCAL (codestart)) - 0x10000)
|
|
#else
|
|
ljmp $0, $ABS(LOCAL (codestart))
|
|
#endif
|
|
|
|
/*
|
|
* This is a special data area.
|
|
*/
|
|
|
|
. = _start + GRUB_DECOMPRESSOR_MACHINE_COMPRESSED_SIZE
|
|
LOCAL(compressed_size):
|
|
.long 0
|
|
. = _start + GRUB_DECOMPRESSOR_MACHINE_UNCOMPRESSED_SIZE
|
|
LOCAL(uncompressed_size):
|
|
.long 0
|
|
|
|
. = _start + GRUB_KERNEL_I386_PC_REED_SOLOMON_REDUNDANCY
|
|
reed_solomon_redundancy:
|
|
.long 0
|
|
|
|
/*
|
|
* This is the area for all of the special variables.
|
|
*/
|
|
|
|
LOCAL(boot_dev):
|
|
.byte 0xFF, 0xFF, 0xFF
|
|
LOCAL(boot_drive):
|
|
.byte 0x00
|
|
|
|
/* the real mode code continues... */
|
|
LOCAL (codestart):
|
|
cli /* we're not safe here! */
|
|
|
|
/* set up %ds, %ss, and %es */
|
|
xorw %ax, %ax
|
|
movw %ax, %ds
|
|
movw %ax, %ss
|
|
movw %ax, %es
|
|
|
|
/* set up the real mode/BIOS stack */
|
|
movl $GRUB_MEMORY_MACHINE_REAL_STACK, %ebp
|
|
movl %ebp, %esp
|
|
|
|
sti /* we're safe again */
|
|
|
|
/* save the boot drive */
|
|
ADDR32 movb %dl, LOCAL(boot_drive)
|
|
|
|
/* reset disk system (%ah = 0) */
|
|
int $0x13
|
|
|
|
/* transition to protected mode */
|
|
DATA32 call real_to_prot
|
|
|
|
/* The ".code32" directive takes GAS out of 16-bit mode. */
|
|
.code32
|
|
|
|
incl %eax
|
|
cld
|
|
call grub_gate_a20
|
|
|
|
movl LOCAL(compressed_size), %edx
|
|
addl $(LOCAL(decompressor_end) - GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART - _start), %edx
|
|
movl reed_solomon_redundancy, %ecx
|
|
leal _start + GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART, %eax
|
|
cld
|
|
call EXT_C (grub_reed_solomon_recover)
|
|
jmp post_reed_solomon
|
|
|
|
#include "../../../kern/i386/realmode.S"
|
|
|
|
#include <rs_decoder.S>
|
|
|
|
.text
|
|
|
|
. = _start + GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART
|
|
/*
|
|
* Support for booting GRUB from a Multiboot boot loader (e.g. GRUB itself).
|
|
* This uses the a.out kludge to load raw binary to the area starting at 1MB,
|
|
* and relocates itself after loaded.
|
|
*/
|
|
.p2align 2 /* force 4-byte alignment */
|
|
multiboot_header:
|
|
/* magic */
|
|
.long 0x1BADB002
|
|
/* flags */
|
|
.long (1 << 16)
|
|
/* checksum */
|
|
.long -0x1BADB002 - (1 << 16)
|
|
/* header addr */
|
|
.long multiboot_header - _start + 0x100000 + 0x200
|
|
/* load addr */
|
|
.long 0x100000
|
|
/* load end addr */
|
|
.long 0
|
|
/* bss end addr */
|
|
.long 0
|
|
/* entry addr */
|
|
.long multiboot_entry - _start + 0x100000 + 0x200
|
|
|
|
multiboot_entry:
|
|
.code32
|
|
/* obtain the boot device */
|
|
movl 12(%ebx), %edx
|
|
|
|
movl $GRUB_MEMORY_MACHINE_PROT_STACK, %ebp
|
|
movl %ebp, %esp
|
|
|
|
/* relocate the code */
|
|
movl $(LOCAL(decompressor_end) + 0x200), %ecx
|
|
addl LOCAL(compressed_size) - _start + 0x100000 + 0x200, %ecx
|
|
movl $0x100000, %esi
|
|
movl $GRUB_BOOT_MACHINE_KERNEL_ADDR, %edi
|
|
cld
|
|
rep
|
|
movsb
|
|
/* jump to the real address */
|
|
movl $multiboot_trampoline, %eax
|
|
jmp *%eax
|
|
|
|
multiboot_trampoline:
|
|
/* fill the boot information */
|
|
movl %edx, LOCAL(boot_dev)
|
|
shrl $24, %edx
|
|
/* enter the usual booting */
|
|
call prot_to_real
|
|
.code16
|
|
jmp LOCAL (codestart)
|
|
.code32
|
|
|
|
post_reed_solomon:
|
|
|
|
#ifdef ENABLE_LZMA
|
|
movl $GRUB_MEMORY_MACHINE_DECOMPRESSION_ADDR, %edi
|
|
movl $LOCAL(decompressor_end), %esi
|
|
pushl %edi
|
|
movl LOCAL (uncompressed_size), %ecx
|
|
leal (%edi, %ecx), %ebx
|
|
/* Don't remove this push: it's an argument. */
|
|
push %ecx
|
|
call _LzmaDecodeA
|
|
pop %ecx
|
|
/* _LzmaDecodeA clears DF, so no need to run cld */
|
|
popl %esi
|
|
#endif
|
|
|
|
movl LOCAL(boot_dev), %edx
|
|
movl $prot_to_real, %edi
|
|
movl $real_to_prot, %ecx
|
|
jmp *%esi
|
|
|
|
/*
|
|
* grub_gate_a20(int on)
|
|
*
|
|
* Gate address-line 20 for high memory.
|
|
*
|
|
* This routine is probably overconservative in what it does, but so what?
|
|
*
|
|
* It also eats any keystrokes in the keyboard buffer. :-(
|
|
*/
|
|
|
|
grub_gate_a20:
|
|
movl %eax, %edx
|
|
|
|
gate_a20_test_current_state:
|
|
/* first of all, test if already in a good state */
|
|
call gate_a20_check_state
|
|
cmpb %al, %dl
|
|
jnz gate_a20_try_bios
|
|
ret
|
|
|
|
gate_a20_try_bios:
|
|
/* second, try a BIOS call */
|
|
pushl %ebp
|
|
call prot_to_real
|
|
|
|
.code16
|
|
movw $0x2400, %ax
|
|
testb %dl, %dl
|
|
jz 1f
|
|
incw %ax
|
|
1: int $0x15
|
|
|
|
DATA32 call real_to_prot
|
|
.code32
|
|
|
|
popl %ebp
|
|
call gate_a20_check_state
|
|
cmpb %al, %dl
|
|
jnz gate_a20_try_system_control_port_a
|
|
ret
|
|
|
|
gate_a20_try_system_control_port_a:
|
|
/*
|
|
* In macbook, the keyboard test would hang the machine, so we move
|
|
* this forward.
|
|
*/
|
|
/* fourth, try the system control port A */
|
|
inb $0x92
|
|
andb $(~0x03), %al
|
|
testb %dl, %dl
|
|
jz 6f
|
|
orb $0x02, %al
|
|
6: outb $0x92
|
|
|
|
/* When turning off Gate A20, do not check the state strictly,
|
|
because a failure is not fatal usually, and Gate A20 is always
|
|
on some modern machines. */
|
|
testb %dl, %dl
|
|
jz 7f
|
|
call gate_a20_check_state
|
|
cmpb %al, %dl
|
|
jnz gate_a20_try_keyboard_controller
|
|
7: ret
|
|
|
|
gate_a20_flush_keyboard_buffer:
|
|
inb $0x64
|
|
andb $0x02, %al
|
|
jnz gate_a20_flush_keyboard_buffer
|
|
2:
|
|
inb $0x64
|
|
andb $0x01, %al
|
|
jz 3f
|
|
inb $0x60
|
|
jmp 2b
|
|
3:
|
|
ret
|
|
|
|
gate_a20_try_keyboard_controller:
|
|
/* third, try the keyboard controller */
|
|
call gate_a20_flush_keyboard_buffer
|
|
|
|
movb $0xd1, %al
|
|
outb $0x64
|
|
4:
|
|
inb $0x64
|
|
andb $0x02, %al
|
|
jnz 4b
|
|
|
|
movb $0xdd, %al
|
|
testb %dl, %dl
|
|
jz 5f
|
|
orb $0x02, %al
|
|
5: outb $0x60
|
|
call gate_a20_flush_keyboard_buffer
|
|
|
|
/* output a dummy command (USB keyboard hack) */
|
|
movb $0xff, %al
|
|
outb $0x64
|
|
call gate_a20_flush_keyboard_buffer
|
|
|
|
call gate_a20_check_state
|
|
cmpb %al, %dl
|
|
/* everything failed, so restart from the beginning */
|
|
jnz gate_a20_try_bios
|
|
ret
|
|
|
|
gate_a20_check_state:
|
|
/* iterate the checking for a while */
|
|
movl $100, %ecx
|
|
1:
|
|
call 3f
|
|
cmpb %al, %dl
|
|
jz 2f
|
|
loop 1b
|
|
2:
|
|
ret
|
|
3:
|
|
pushl %ebx
|
|
pushl %ecx
|
|
xorl %eax, %eax
|
|
/* compare the byte at 0x8000 with that at 0x108000 */
|
|
movl $GRUB_BOOT_MACHINE_KERNEL_ADDR, %ebx
|
|
pushl %ebx
|
|
/* save the original byte in CL */
|
|
movb (%ebx), %cl
|
|
/* store the value at 0x108000 in AL */
|
|
addl $0x100000, %ebx
|
|
movb (%ebx), %al
|
|
/* try to set one less value at 0x8000 */
|
|
popl %ebx
|
|
movb %al, %ch
|
|
decb %ch
|
|
movb %ch, (%ebx)
|
|
/* serialize */
|
|
outb %al, $0x80
|
|
outb %al, $0x80
|
|
/* obtain the value at 0x108000 in CH */
|
|
pushl %ebx
|
|
addl $0x100000, %ebx
|
|
movb (%ebx), %ch
|
|
/* this result is 1 if A20 is on or 0 if it is off */
|
|
subb %ch, %al
|
|
xorb $1, %al
|
|
/* restore the original */
|
|
popl %ebx
|
|
movb %cl, (%ebx)
|
|
popl %ecx
|
|
popl %ebx
|
|
ret
|
|
|
|
#ifdef ENABLE_LZMA
|
|
#include "lzma_decode.S"
|
|
#endif
|
|
|
|
.p2align 4
|
|
|
|
LOCAL(decompressor_end):
|