minix/kernel/arch/i386/multiboot.S
Erik van der Kouwe df0ba02a38 Multiboot support (contributed by Feiran "Fam" Zheng);
keep in mind that GRUB needs to be patched to read MFS for now;
use /boot/image_latest to boot the last compiled image in GRUB
2010-07-23 14:24:34 +00:00

117 lines
2.5 KiB
ArmAsm

#include "kernel/kernel.h" /* configures the kernel */
#include <minix/config.h>
#include <minix/const.h>
#include <minix/com.h>
#include <machine/interrupt.h>
#include "archconst.h"
#include "kernel/const.h"
#include "kernel/proc.h"
#include "sconst.h"
#include "multiboot.h"
#define GDT_SET_ENTRY(selector, base, limit) \
mov %ebp, %edi; \
add $(_gdt + selector), %edi; \
mov base, %eax; \
movw %ax, 2(%edi); \
shr $16, %eax; \
movb %al, 4(%edi); \
and $0xff00, %ax; \
andw $0xff, 6(%edi); \
or %ax, 6(%edi); \
mov limit, %eax; \
movw %ax, (%edi); \
shr $16, %eax; \
and $0xf, %ax; \
andb $0xf0, 6(%edi); \
or %ax, 6(%edi); \
.globl _pre_init
.globl multiboot_init
.globl kernel_init
multiboot_init:
/* Get size of kernel text */
mov MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_text, %ecx
/* Get size of kernel text and ceil to 0x1000, and it's the offset
of data seg */
mov %ecx, %eax
dec %eax
and $0xfffff000, %eax
add $0x1000, %eax
/* Calculate and save kernel data base address */
mov $(MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET), %ebp
add %eax, %ebp
mov %ebp, _kernel_data_addr(%ebp)
/* Init text seg */
GDT_SET_ENTRY(CS_SELECTOR, \
$(MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_ENTRY_OFFSET), \
%ecx)
/* Init data seg */
GDT_SET_ENTRY(DS_SELECTOR, \
%ebp, \
MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_total)
/* Make up monitor data seg, the same value as DS, different entry */
GDT_SET_ENTRY(SS_SELECTOR, \
%ebp, \
MULTIBOOT_LOAD_ADDRESS + MULTIBOOT_KERNEL_a_total)
/* Make up monitor text seg, used to return to real mode when poweroff */
GDT_SET_ENTRY(MON_CS_SELECTOR, \
$BIOS_POWEROFF_ENTRY, \
$0xffff)
mov $(GDT_SIZE*DESC_SIZE), %eax
mov %ebp, %edi
add $(_gdt + GDT_SELECTOR), %edi
mov %ax, (%edi)
mov %ebp, %eax
add $_gdt, %eax
mov %eax, 2(%edi)
lgdt (%edi)
ljmp $(CS_SELECTOR), $reload_cs
reload_cs:
mov $DS_SELECTOR, %eax
mov %eax, %ds
mov %eax, %ss
mov %eax, %es
mov $(multiboot_stack + MULTIBOOT_STACK_SIZE), %esp
push %ebx
call _pre_init
add $4, %esp
/* return to old boot code of kernel */
push %eax
push $MULTIBOOT_PARAM_BUF_SIZE
push $_multiboot_param_buf
push $0
mov $ES_SELECTOR, %eax
mov %eax, %es
jmp kernel_init
.data
.globl _kernel_data_addr
_kernel_data_addr:
.long 0
.globl _a_out_headers
_a_out_headers:
.space NR_BOOT_PROCS * 32 /* is A_MINHDR */
.globl _multiboot_param_buf
_multiboot_param_buf:
.space MULTIBOOT_PARAM_BUF_SIZE
multiboot_stack:
.space MULTIBOOT_STACK_SIZE + 4