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跳入保护模式时出现三重故障(Triple fault when jumping into protected mode)

 我正在开发一个启动加载程序，它将在切换到保护模式后启动到一个简单的内核。 我在第四章或第五章的某个地方使用了本文作为教程。 从理论上讲，它应该以16位实模式启动，将内核加载到内存中，切换到32位保护模式并开始执行内核代码。  
 但是，当我切换到保护模式并跳远或跳转到另一个段时，它会出现三重故障。 这是主引导扇区代码：  
[org 0x7c00]

KERNEL_OFFSET equ 0x1000

mov [BOOT_DRIVE], dl    ;Get the current boot drive from the BIOS

mov bp, 0x9000          ;Set up stack, with enough room to grow downwards
mov sp, bp

mov bx, REAL_MODE_MSG
call print_string

call load_kernel

call switch_to_pm

jmp $                       ;Jump to current position and loop forever

%include "boot/util/print_string.asm"
%include "boot/util/disk.asm"
%include "boot/gdt/gdt.asm"
%include "boot/util/print_string_pm.asm"
%include "boot/switch_to_pm.asm"

[bits 16]
load_kernel:
    mov bx, LOAD_KERNEL_MSG ;Print a message saying we are loading the kernel
    call print_string
    mov bx, KERNEL_OFFSET       ;Set up disk_load routine parameters
    mov dh, 15
    mov dl, [BOOT_DRIVE]
    call disk_load              ;Call disk_load
    ret

[bits 32]
BEGIN_PM:
    mov ebx, PROT_MODE_MSG
    call print_string_pm
    call KERNEL_OFFSET

    jmp $

; Data
BOOT_DRIVE: db 0
REAL_MODE_MSG: db "Started in real mode.", 0
PROT_MODE_MSG: db "Successfully entered 32-bit protected mode.", 0
LOAD_KERNEL_MSG: db "Loading Kernel into memory", 0

; Bootsector padding
times 510-($-$$) db 0
dw 0xaa55
 
 这是GDT：  
;Global Descriptor Table
gdt_start:

gdt_null:   ; We need a null descriptor at the start (8 bytes)
    dd 0x0
    dd 0x0

gdt_code:   ; Code segment descriptor
    ; Base=0x0, Limit=0xfffff
    ; 1st flags : (present)1 (privilege)00 (descriptor type)1 -> 1001b
    ; type flags : (code)1 (conforming)0 (readable)1 (accessed)0 -> 1010b
    ; 2nd flags : (granularity)1 (32 - bit default)1 (64 - bit seg)0 (AVL)0 -> 1100b
    dw 0xffff       ; Limit (bits 0-15)
    dw 0x0      ; Base (0-15)
    dw 0x0          ; Base (16-23)
    db 10011010b    ; 1st flags and type flags
    db 11001111b    ; 2nd flags and Limit (16-19)
    db 0x0          ; Base (24-31)

gdt_data:   ; Data segment descriptor
    ;Same as CSD except for type flags
    ; (code)0 (expand down)0 (writable)1 (accessed)0 -> 0010b
    dw 0xffff       ; Limit (bits 0-15)
    dw 0x0          ; Base (0-15)
    dw 0x0          ; Base (16-23)
    db 10010010b    ; 1st flags and type flags
    db 11001111b    ; 2nd flags and Limit (16-19)
    db 0x0          ; Base (24-31)

gdt_end:


;GDT Descriptor
gdt_descriptor:
    dw gdt_end - gdt_start - 1
    dd gdt_start

;Some Constants
CODE_SEG equ gdt_code - gdt_start
DATA_SEG equ gdt_data - gdt_start
 
 以下是切换到保护模式的代码，其中三重故障：  
[bits 16]
switch_to_pm:
    cli
    lgdt [gdt_descriptor]   ; load the gdt
    mov eax, cr0            ; turn pm on
    or eax, 0x1
    mov cr0, eax
    jmp CODE_SEG:init_pm    ; THIS IS WHERE THE PROBLEM IS!

[bits 32]
init_pm:
    mov ax, DATA_SEG ; Point segment registers to the data
    mov ds, ax       ; selector defined in the gdt
    mov ss, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ebp, 0x90000 ; Update our stack
    mov esp, ebp
    call BEGIN_PM ;Move on
 
 当我在某个位置放置一个jmp $指令空闲时，就在jmp CODE_SEG:init_pm指令之前，它在那里闲置并且没有三重故障。 当我将它放在该指令之后，在标签init_pm ，它会发生三重故障。 所以我很确定这是原因。 我不太清楚为什么，也许这是GDT的一个问题。 我是操作系统开发和引导加载程序的新手。 有关如何解决这个问题的任何建议？ 

I'm developing a boot loader, which will boot into a simple kernel after switching into protected mode. I used this paper as a tutorial, somewhere in chapter four or five. In theory it is supposed to start in 16-bit real mode, load the kernel into memory, switch to 32-bit protected mode and start executing the kernel code. 
However, when I switch into protected mode and far jump or jump to another segment, it triple faults. Here is the main boot sector code: 
[org 0x7c00]

KERNEL_OFFSET equ 0x1000

mov [BOOT_DRIVE], dl    ;Get the current boot drive from the BIOS

mov bp, 0x9000          ;Set up stack, with enough room to grow downwards
mov sp, bp

mov bx, REAL_MODE_MSG
call print_string

call load_kernel

call switch_to_pm

jmp $                       ;Jump to current position and loop forever

%include "boot/util/print_string.asm"
%include "boot/util/disk.asm"
%include "boot/gdt/gdt.asm"
%include "boot/util/print_string_pm.asm"
%include "boot/switch_to_pm.asm"

[bits 16]
load_kernel:
    mov bx, LOAD_KERNEL_MSG ;Print a message saying we are loading the kernel
    call print_string
    mov bx, KERNEL_OFFSET       ;Set up disk_load routine parameters
    mov dh, 15
    mov dl, [BOOT_DRIVE]
    call disk_load              ;Call disk_load
    ret

[bits 32]
BEGIN_PM:
    mov ebx, PROT_MODE_MSG
    call print_string_pm
    call KERNEL_OFFSET

    jmp $

; Data
BOOT_DRIVE: db 0
REAL_MODE_MSG: db "Started in real mode.", 0
PROT_MODE_MSG: db "Successfully entered 32-bit protected mode.", 0
LOAD_KERNEL_MSG: db "Loading Kernel into memory", 0

; Bootsector padding
times 510-($-$$) db 0
dw 0xaa55
 
Here is the GDT: 
;Global Descriptor Table
gdt_start:

gdt_null:   ; We need a null descriptor at the start (8 bytes)
    dd 0x0
    dd 0x0

gdt_code:   ; Code segment descriptor
    ; Base=0x0, Limit=0xfffff
    ; 1st flags : (present)1 (privilege)00 (descriptor type)1 -> 1001b
    ; type flags : (code)1 (conforming)0 (readable)1 (accessed)0 -> 1010b
    ; 2nd flags : (granularity)1 (32 - bit default)1 (64 - bit seg)0 (AVL)0 -> 1100b
    dw 0xffff       ; Limit (bits 0-15)
    dw 0x0      ; Base (0-15)
    dw 0x0          ; Base (16-23)
    db 10011010b    ; 1st flags and type flags
    db 11001111b    ; 2nd flags and Limit (16-19)
    db 0x0          ; Base (24-31)

gdt_data:   ; Data segment descriptor
    ;Same as CSD except for type flags
    ; (code)0 (expand down)0 (writable)1 (accessed)0 -> 0010b
    dw 0xffff       ; Limit (bits 0-15)
    dw 0x0          ; Base (0-15)
    dw 0x0          ; Base (16-23)
    db 10010010b    ; 1st flags and type flags
    db 11001111b    ; 2nd flags and Limit (16-19)
    db 0x0          ; Base (24-31)

gdt_end:


;GDT Descriptor
gdt_descriptor:
    dw gdt_end - gdt_start - 1
    dd gdt_start

;Some Constants
CODE_SEG equ gdt_code - gdt_start
DATA_SEG equ gdt_data - gdt_start
 
Here is the code for switching into protected mode, where it triple faults: 
[bits 16]
switch_to_pm:
    cli
    lgdt [gdt_descriptor]   ; load the gdt
    mov eax, cr0            ; turn pm on
    or eax, 0x1
    mov cr0, eax
    jmp CODE_SEG:init_pm    ; THIS IS WHERE THE PROBLEM IS!

[bits 32]
init_pm:
    mov ax, DATA_SEG ; Point segment registers to the data
    mov ds, ax       ; selector defined in the gdt
    mov ss, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ebp, 0x90000 ; Update our stack
    mov esp, ebp
    call BEGIN_PM ;Move on
 
When I place a jmp $ instruction to idle at a certain spot, right before the jmp CODE_SEG:init_pm instruction, it idles there and does not triple fault. When I place it after that instruction, within the label init_pm, it does triple fault. So I am fairly sure that it is the cause. I'm not too sure why, maybe it's an issue with the GDT. I am new to operating system development and boot loaders. Any suggestions on how to solve this problem?

原文：https://stackoverflow.com/questions/36562268

更新时间：2023-01-15 18:01

最满意答案

 使用领带 ：  
#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

{   package File;

    sub new {
        bless ['hello'], shift
    }

    sub text {
        my $self = shift;
        if (@_) {
            $self->[0] = shift;
        } else {
            return $self->[0]
        }
    }
}

{   package FileVar;
    use Tie::Scalar;
    use parent qw( -norequire Tie::StdScalar );

    sub TIESCALAR {
        my ($class, $obj) = @_;
        bless \$obj, $class
    }

    sub FETCH {
        my $self = shift;
        ${$self}->text()
    }

    sub STORE {
        die 'Read only!';

        # Or, do you want to change the object by changing the var, too?
        my ($self, $value) = @_;
        ${$self}->text($value);
    }

}

my $file = 'File'->new();
tie my $text, 'FileVar', $file;
say $text;
$file->text('goodbye');
say $text;

# Die or change the object:
$text = 'Magic!';
say $file->text;

Use tie: 
#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

{   package File;

    sub new {
        bless ['hello'], shift
    }

    sub text {
        my $self = shift;
        if (@_) {
            $self->[0] = shift;
        } else {
            return $self->[0]
        }
    }
}

{   package FileVar;
    use Tie::Scalar;
    use parent qw( -norequire Tie::StdScalar );

    sub TIESCALAR {
        my ($class, $obj) = @_;
        bless \$obj, $class
    }

    sub FETCH {
        my $self = shift;
        ${$self}->text()
    }

    sub STORE {
        die 'Read only!';

        # Or, do you want to change the object by changing the var, too?
        my ($self, $value) = @_;
        ${$self}->text($value);
    }

}

my $file = 'File'->new();
tie my $text, 'FileVar', $file;
say $text;
$file->text('goodbye');
say $text;

# Die or change the object:
$text = 'Magic!';
say $file->text;

跳入保护模式时出现三重故障(Triple fault when jumping into protected mode)

最满意答案

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