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#
# Copyright (C) 2001-2004 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#include <arch/boot/boot.h>
#include <arch/boot/memmap.h>
#include <arch/mm/page.h>
#include <arch/pm.h>
.section K_TEXT_START, "ax"
.global kernel_image_start
KTEXT=8
KDATA=16
.code16
#
# This is where we require any SPARTAN-kernel-compatible boot loader
# to pass control in real mode.
#
# Protected mode tables are statically initialised during compile
# time. So we can just load the respective table registers and
# switch to protected mode.
#
kernel_image_start:
cli
xorw %ax, %ax
movw %ax, %ds
movw %ax, %es
movw %ax, %ss # initialize stack segment register
movl $BOOTSTRAP_OFFSET - 0x400, %esp # initialize stack pointer
call memmap_arch_init
lgdt real_bootstrap_gdtr_boot # initialize Global Descriptor Table register
movl %cr0, %eax
orl $0x1, %eax
movl %eax, %cr0 # switch to protected mode
jmpl $KTEXT, $boot_image_start
.code32
.align 4
multiboot_header:
.long MULTIBOOT_HEADER_MAGIC
.long MULTIBOOT_HEADER_FLAGS
.long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS) # checksum
.long multiboot_header + BOOT_OFFSET
.long unmapped_ktext_start + BOOT_OFFSET
.long 0
.long 0
.long multiboot_image_start + BOOT_OFFSET
boot_image_start:
movw $KDATA, %ax
movw %ax, %es
movw %ax, %gs
movw %ax, %fs
movw %ax, %ds # kernel data + stack
movw %ax, %ss
movb $0xd1, %al # enable A20 using i8042 controller
outb %al, $0x64
movb $0xdf, %al
outb %al, $0x60
movl $BOOTSTRAP_OFFSET, %esi
movl $BOOTSTRAP_OFFSET + BOOT_OFFSET, %edi
movl $_hardcoded_kernel_size, %ecx
cld
rep movsb
call map_kernel # map kernel and turn paging on
call main_bsp # never returns
cli
hlt
multiboot_image_start:
movl $BOOTSTRAP_OFFSET - 0x400, %esp # initialize stack pointer
lgdt protected_bootstrap_gdtr - 0x80000000 # initialize Global Descriptor Table register
movw $KDATA, %cx
movw %cx, %es
movw %cx, %gs
movw %cx, %fs
movw %cx, %ds # kernel data + stack
movw %cx, %ss
jmpl $KTEXT, $multiboot_meeting_point + BOOT_OFFSET
multiboot_meeting_point:
pushl %ebx # save parameters from GRUB
pushl %eax
movl $BOOTSTRAP_OFFSET + BOOT_OFFSET, %esi
movl $BOOTSTRAP_OFFSET, %edi
movl $_hardcoded_unmapped_size, %ecx
cld
rep movsb
call map_kernel # map kernel and turn paging on
popl %eax
popl %ebx
cmpl $MULTIBOOT_LOADER_MAGIC, %eax # compare GRUB signature
je valid_boot
xorl %ecx, %ecx # no memory size or map available
movl %ecx, e801memorysize
movl %ecx, e820counter
jmp invalid_boot
valid_boot:
movl (%ebx), %eax # ebx = physical address of struct multiboot_info
bt $0, %eax # mbi->flags[0] (mem_lower, mem_upper valid)
jc mem_valid
xorl %ecx, %ecx
jmp mem_invalid
mem_valid:
movl 4(%ebx), %ecx # mbi->mem_lower
addl 8(%ebx), %ecx # mbi->mem_upper
mem_invalid:
movl %ecx, e801memorysize
bt $3, %eax # mbi->flags[3] (mods_count, mods_addr valid)
jc mods_valid
xorl %ecx, %ecx
xorl %edx, %edx
jmp mods_invalid
mods_valid:
mods_invalid:
movl %ecx, init_addr
movl %edx, init_size
bt $6, %eax # mbi->flags[6] (mmap_length, mmap_addr valid)
jc mmap_valid
xorl %edx, %edx
jmp mmap_invalid
mmap_valid:
movl 44(%ebx), %ecx # mbi->mmap_length
movl 48(%ebx), %esi # mbi->mmap_addr
movl $e820table, %edi
xorl %edx, %edx
mmap_loop:
cmpl $0, %ecx
jle mmap_end
movl 4(%esi), %eax # mmap->base_addr_low
movl %eax, (%edi)
movl 8(%esi), %eax # mmap->base_addr_high
movl %eax, 4(%edi)
movl 12(%esi), %eax # mmap->length_low
movl %eax, 8(%edi)
movl 16(%esi), %eax # mmap->length_high
movl %eax, 12(%edi)
movl 20(%esi), %eax # mmap->type
movl %eax, 16(%edi)
movl (%esi), %eax # mmap->size
addl $0x4, %eax
addl %eax, %esi
subl %eax, %ecx
addl $MEMMAP_E820_RECORD_SIZE, %edi
incl %edx
jmp mmap_loop
mmap_end:
mmap_invalid:
movl %edx, e820counter
invalid_boot:
call main_bsp - BOOT_OFFSET # never returns
cli
hlt
.global map_kernel
map_kernel:
#
# Here we setup mapping for both the unmapped and mapped sections of the kernel.
# For simplicity, we map the entire 4G space.
#
movl %cr4, %ecx
orl $(1<<4), %ecx
movl %ecx, %cr4 # turn PSE on
movl $(page_directory+0), %esi
movl $(page_directory+2048), %edi
xorl %ecx, %ecx
xorl %ebx, %ebx
0:
movl $((1<<7)|(1<<0)), %eax
orl %ebx, %eax
movl %eax, (%esi,%ecx,4) # mapping 0x00000000+%ecx*4M => 0x00000000+%ecx*4M
movl %eax, (%edi,%ecx,4) # mapping 0x80000000+%ecx*4M => 0x00000000+%ecx*4M
addl $(4*1024*1024), %ebx
incl %ecx
cmpl $512, %ecx
jl 0b
movl %esi, %cr3
# turn paging on
movl %cr0, %ebx
orl $(1<<31), %ebx
movl %ebx, %cr0
ret
.section K_DATA_START, "aw", @progbits
.align 4096
page_directory:
.space 4096, 0
.global real_bootstrap_gdtr_boot
real_bootstrap_gdtr_boot:
.word selector(GDT_ITEMS)
.long KA2PA(gdt)-BOOT_OFFSET