我如何用我的内核创建可启动的CD映像？
我有一个内核，启动我使用命令qemu-system-i386 -kernel kernel.bin 。 有什么办法可以创建可启动的磁盘映像以启动与qemu-system-i386 -cdrom CD.iso ？
我正在用这些命令在Linux中编译代码：
nasm -f elf32 kernel.asm -o kernelasm.o
gcc -m32 -c kernel.c -o kernelc.o
ld -m elf_i386 -T link.ld -o kernel.bin kernelasm.o kernelc.o
然后用qemu-system-i386 -kernel kernel.bin
代码：kernel.asm：
[BITS 32]
SECTION .text
align 4
dd 0x1BADB002
dd 0x00
dd - (0x1BADB002 + 0x00)
global start
global keyboard_handler
global read_port
global write_port
global load_idt
extern kmain
extern keyboard_handler_main
read_port:
mov edx, [esp + 4]
in al, dx
ret
write_port:
mov edx, [esp + 4]
mov al, [esp + 4 + 4]
out dx, al
ret
load_idt:
mov edx, [esp + 4]
lidt [edx]
sti
ret
keyboard_handler:
call keyboard_handler_main
iretd
start:
cli
mov esp, stack_space
call kmain
hlt
section .bss
resb 8192
stack_space:
kernel.c：
#include "keyboard_map.h"
#define LINES 25
#define COLUMNS_IN_LINE 80
#define BYTES_FOR_EACH_ELEMENT 2
#define SCREENSIZE BYTES_FOR_EACH_ELEMENT * COLUMNS_IN_LINE * LINES
#define KEYBOARD_DATA_PORT 0x60
#define KEYBOARD_STATUS_PORT 0x64
#define IDT_SIZE 256
#define INTERRUPT_GATE 0x8e
#define KERNEL_CODE_SEGMENT_OFFSET 0x08
#define ENTER_KEY_CODE 0x1C
extern unsigned char keyboard_map[128];
extern void keyboard_handler(void);
extern char read_port(unsigned short port);
extern void write_port(unsigned short port, unsigned char data);
extern void load_idt(unsigned long *idt_ptr);
unsigned int current_loc = 0;
char *vidptr = (char*)0xb8000;
struct IDT_entry {
unsigned short int offset_lowerbits;
unsigned short int selector;
unsigned char zero;
unsigned char type_attr;
unsigned short int offset_higherbits;
};
struct IDT_entry IDT[IDT_SIZE];
void idt_init(void)
{
unsigned long keyboard_address;
unsigned long idt_address;
unsigned long idt_ptr[2];
keyboard_address = (unsigned long)keyboard_handler;
IDT[0x21].offset_lowerbits = keyboard_address & 0xffff;
IDT[0x21].selector = KERNEL_CODE_SEGMENT_OFFSET;
IDT[0x21].zero = 0;
IDT[0x21].type_attr = INTERRUPT_GATE;
IDT[0x21].offset_higherbits = (keyboard_address & 0xffff0000) >> 16;
write_port(0x20 , 0x11);
write_port(0xA0 , 0x11);
write_port(0x21 , 0x20);
write_port(0xA1 , 0x28);
write_port(0x21 , 0x00);
write_port(0xA1 , 0x00);
write_port(0x21 , 0x01);
write_port(0xA1 , 0x01);
write_port(0x21 , 0xff);
write_port(0xA1 , 0xff);
idt_address = (unsigned long)IDT ;
idt_ptr[0] = (sizeof (struct IDT_entry) * IDT_SIZE) + ((idt_address & 0xffff) << 16);
idt_ptr[1] = idt_address >> 16 ;
load_idt(idt_ptr);
}
void kb_init(void)
{
write_port(0x21 , 0xFD);
}
void kprint(const char *str)
{
unsigned int i = 0;
while (str[i] != ' ') {
vidptr[current_loc++] = str[i++];
vidptr[current_loc++] = 0x07;
}
}
void kprint_newline(void)
{
unsigned int line_size = BYTES_FOR_EACH_ELEMENT * COLUMNS_IN_LINE;
current_loc = current_loc + (line_size - current_loc % (line_size));
}
void clear_screen(void)
{
unsigned int i = 0;
while (i < SCREENSIZE) {
vidptr[i++] = ' ';
vidptr[i++] = 0x07;
}
}
void keyboard_handler_main(void)
{
unsigned char status;
char keycode;
write_port(0x20, 0x20);
status = read_port(KEYBOARD_STATUS_PORT);
if (status & 0x01) {
keycode = read_port(KEYBOARD_DATA_PORT);
if(keycode < 0)
return;
if(keycode == ENTER_KEY_CODE) {
kprint_newline();
return;
}
vidptr[current_loc++] = keyboard_map[(unsigned char) keycode];
vidptr[current_loc++] = 0x07;
}
}
void kmain(void)
{
const char *str = "my first kernel with keyboard support";
clear_screen();
kprint(str);
kprint_newline();
kprint_newline();
idt_init();
kb_init();
while(1);
}
keyboard_map.h：
unsigned char keyboard_map[128] =
{
0, 27, '1', '2', '3', '4', '5', '6', '7', '8', /* 9 */
'9', '0', '-', '=', 'b', /* Backspace */
't', /* Tab */
'q', 'w', 'e', 'r', /* 19 */
't', 'y', 'u', 'i', 'o', 'p', '[', ']', 'n', /* Enter key */
0, /* 29 - Control */
'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', /* 39 */
''', '`', 0, /* Left shift */
'', 'z', 'x', 'c', 'v', 'b', 'n', /* 49 */
'm', ',', '.', '/', 0, /* Right shift */
'*',
0, /* Alt */
' ', /* Space bar */
0, /* Caps lock */
0, /* 59 - F1 key ... > */
0, 0, 0, 0, 0, 0, 0, 0,
0, /* < ... F10 */
0, /* 69 - Num lock*/
0, /* Scroll Lock */
0, /* Home key */
0, /* Up Arrow */
0, /* Page Up */
'-',
0, /* Left Arrow */
0,
0, /* Right Arrow */
'+',
0, /* 79 - End key*/
0, /* Down Arrow */
0, /* Page Down */
0, /* Insert Key */
0, /* Delete Key */
0, 0, 0,
0, /* F11 Key */
0, /* F12 Key */
0, /* All other keys are undefined */
};
link.ld：
OUTPUT_FORMAT(elf32-i386)
ENTRY(start)
SECTIONS
{
. = 0x100000;
.text : { *(.text) }
.data : { *(.data) }
.bss : { *(.bss) }
}
首先我给你介绍启动过程如何真正起作用的基本概念。 实际上，当你运行命令qemu-system-i386 -kernel kernel.bin Qemu将你的内核二进制文件加载到内存0x7c000处，从那里开始进一步的操作。 如果你想从ISO引导，那么你必须告诉BIOS，在我的iso中有一个可引导的映像（标记引导标志），并给出正确的指示来放置你的内核。
怎么做？
你必须设置一个引导加载程序，可以在你的BIOS中加载0x7c000和更高版本。它会将你的内核映像加载到内存中并跳转到内核入口点。
因此，请标记您的ISO活动（启动标志）并添加启动加载程序代码。
我可以看到您已经设置了多重启动入口点代码
align 4
dd 0x1BADB002
dd 0x00
dd - (0x1BADB002 + 0x00)
您可以从这里http://wiki.osdev.org/GRUB_2了解更多关于设置grub引导链的信息。您还可以使用syslinux bootloader http://www.syslinux.org/wiki/index.php?title=The_Syslinux_Project
syslinux将isolinux.bin，syslinux.cfg和mboot.c32复制到您的内核二进制映像的构建路径。 配置syslinux.cfg并执行以下命令。
mkisofs.exe -o %OUTPUT_DIR%%BUILD_NAME%.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table %ISO_DIR%