minix/kernel/arch/i386/multiboot.S

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#include "kernel/kernel.h" /* configures the kernel */
#include <minix/config.h>
#include <minix/const.h>
#include <minix/com.h>
#include <machine/asm.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 $(_C_LABEL(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); \
IMPORT(pre_init)
.extern kernel_init
.globl multiboot_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, _C_LABEL(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 $(_C_LABEL(gdt) + GDT_SELECTOR), %edi
mov %ax, (%edi)
mov %ebp, %eax
add $_C_LABEL(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 _C_LABEL(pre_init)
add $4, %esp
/* return to old boot code of kernel */
push %eax
push $MULTIBOOT_PARAM_BUF_SIZE
push $_C_LABEL(multiboot_param_buf)
push $0
mov $ES_SELECTOR, %eax
mov %eax, %es
jmp kernel_init
.data
LABEL(kernel_data_addr)
.long 0
LABEL(a_out_headers)
.space NR_BOOT_PROCS * 32 /* is A_MINHDR */
LABEL(multiboot_param_buf)
.space MULTIBOOT_PARAM_BUF_SIZE
multiboot_stack:
.space MULTIBOOT_STACK_SIZE + 4