3rd (269008768) exception with no resolution

[neil]

Hello everybody !
I'm a newbie in osdev and I'm trying to transform my first mono kernel into a micro kernel architecture. I am also using GRUB and creating a multiboot compliant kernel (http://www.gnu.org/software/grub/manual/multiboot).
But as creating a new kernel initialization, my emulator (Bochs) throws an exception (I think a triple fault, even if I don't know what is it
Here is the log:
00008365740e[CPU  ] exception(): 3rd (13) exception with no resolution, shutdown status is 00h, resetting
========================================================================
Event type: ERROR
Device: [CPU  ]
Message: exception(): 3rd (269008768) exception with no resolution, shutdown status is 7fffd710h, resetting

A ERROR has occurred.  Do you want to:
  cont       - continue execution
  alwayscont - continue execution, and don't ask again.
               This affects only ERROR events from device [CPU  ]
  die        - stop execution now
  abort      - dump core
Choose one of the actions above: [die] die
00008365740i[SYS  ] Last time is 1077442389
00008365740i[XGUI ] Exit.
00008365740i[CPU  ] protected mode
00008365740i[CPU  ] CS.d_b = 32 bit
00008365740i[CPU  ] SS.d_b = 32 bit
00008365740i[CPU  ] | EAX=00000000  EBX=0002bdc0  ECX=000003c6  EDX=00000006
00008365740i[CPU  ] | ESP=001059bc  EBP=001059d4  ESI=0002bed9  EDI=0002beda
00008365740i[CPU  ] | IOPL=0 NV UP EI PL ZR NA PE NC
00008365740i[CPU  ] | SEG selector     base    limit G D
00008365740i[CPU  ] | SEG sltr(index|ti|rpl)     base    limit G D
00008365740i[CPU  ] |  DS:0010( 0002| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] |  ES:0010( 0002| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] |  FS:0010( 0002| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] |  GS:0010( 0002| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] |  SS:0010( 0002| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] |  CS:0008( 0001| 0|  0) 00000000 000fffff 1 1
00008365740i[CPU  ] | EIP=001000e4 (001000e4)
00008365740i[CPU  ] | CR0=0x60000011 CR1=0x00000000 CR2=0x00000000
00008365740i[CPU  ] | CR3=0x00000000 CR4=0x00000000
00008365740i[     ] restoring default signal behavior

The exception is thrown when I try to activate the interruptions via sti:

/* Kernel initialization. */
void cmain (unsigned long address) {
    init_printk () ;
    printk ("Esperanza version 0.0.1\n") ;

    // Init the GDT
    init_gdt () ;

    // Verify the GDT
    kgdtr.size = 0 ;
    kgdtr.address = 0 ;
    asm("sgdtl (kgdtr)");
    printk("GDT address: 0x%x, size: 0x%x\n",
        kgdtr.address, kgdtr.size) ;

    // Init the IDT
    init_idt () ;

    // Verify the GDT
    kidtr.size = 0 ;
    kidtr.address = 0 ;
    asm("sidtl (kidtr)");
    printk("IDT address: 0x%x, size: 0x%x\n",
        kidtr.address, kidtr.size) ;

    init_pic () ;

    init_pit () ;

    // Enable interruptions
    printk ("Back\n") ;
    sti () ;    // <-- EXCEPTION

    // Infinite loop
    for (;;) ;
}

Don't know if anybody had got the same error, or have suggestions, but please help! (And excuse my poor english!)

[bubach]

Are you sure that the IDT is correct?

/ Christoffer

[neil]

Well, I think everything is okay, I used the same code with my last kernel (I had the same error when I put the lidt instruction in the C code instead of the ASM, but don't know why ?!).

Here is the IDT code :

idt.h :

#ifndef __IDT_H
#define __IDT_H

#include <next.h>

#define IDT_ADDRESS 0x800
#define IDT_ENTRY_COUNT 0xff
#define IDT_ENTRY_SIZE 8
#define IDT_SIZE (IDT_ENTRY_COUNT * IDT_ENTRY_SIZE)
#define IDT_ENTRY(i) ((IDT_Entry *) (IDT_ADDRESS + i * IDT_ENTRY_SIZE))

#define INT_GATE  0x8e00

#define cli() asm ("cli")
#define sti() asm ("sti")
#define iret asm ("leave \n \
   sti \n \
                   iret") ;
#define eoi() asm ("mov $0x20, %al \n \
                    out %al, $0x20") ;
#define eoi2() asm ("mov $0x20, %al \n \
                     out %al, $0xa0") ;

/** Entry in the IDT. */
typedef struct {
    /** First part of the offset (bits 0-15) */
    nx_ushort offset_first ;
    /** Selector */
    nx_ushort selector ;
    /** Type of the entry. */
    nx_ushort type ;
    /** Second part of the offset (bits 16-31) */
    nx_ushort offset_second ;
} IDT_Entry __attribute__ ((packed)) ;

/** Structure loaded into IDTR. */
typedef struct {
    /** Size of the IDT. */
    nx_ushort size ;
    /** Address of the IDT. */
    nx_uint address ;
} IDTR __attribute__ ((packed)) ;

IDTR kidtr ;

/** Initialize the IDT. */
void init_idt () ;
void init_idt_entry (void * offset,
                     nx_ushort selector,
                     nx_ushort type,
                     IDT_Entry * entry) ;

/** Catch-all interrupt gate. */
void int_default () ;

#endif


idt.c:

#include <gdt.h>
#include <idt.h>
#include <panic.h>
#include <pic.h>
#include <printk.h>


void init_idt_entry (void * function,
                     nx_ushort selector,
                     nx_ushort type,
                     IDT_Entry * entry) {

    nx_uint offset = (nx_uint) function ;
    entry->offset_first = offset & 0xffff ;
    entry->selector = selector ;
    entry->type = type ;
    entry->offset_second = offset >> 16 ;
}

void init_idt () {

    int i ;
    for (i = 0 ; i < IDT_ENTRY_COUNT ; i++)
        init_idt_entry (int_default, KERNEL_CODE, INT_GATE, IDT_ENTRY (i)) ;

    kidtr.size = IDT_SIZE ;
    kidtr.address = IDT_ADDRESS ;

    // Load IDTR
    asm ("lidtl (kidtr)");

    printk ("\tIDT initialized\n") ;
}

/**
* Used to catch unmanaged interrupts.
*/
void int_default () {

    panic ("Unmanaged interruption") ;
}


And here is the screen before the interruption:
Esperanza version 0.0.1
        GDT initialized
GDT address: 0x0, size: 0x800
        IDT initialized
IDT address: 0x800, size: 0x7f8
        PIT initialized
Back

/ Neil Dökkalfar

[neil]

Don't know why, and THAT's the thing I wanna know, the following code works :

kload.asm

[BITS 32]

%define MULTIBOOT_HEADER_MAGIC 0x1badb002
%define MULTIBOOT_HEADER_FLAGS 0x00000003


global start, _start

extern init_printk, printk, init_gdt, init_idt, init_pic, init_pit, cmain

start:
_start:

jmp multiboot_entry

multiboot_header:


align 4

; Magic number
dd MULTIBOOT_HEADER_MAGIC

; Multiboot flags
dd MULTIBOOT_HEADER_FLAGS

; The checksum
dd - (MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)


multiboot_entry:

mov esp, 0x90000

push 0
popf

; Init the screen
call init_printk

; Display a message
push hello
        call printk
        add esp, 4

; Init the new GDT
call init_gdt
lgdt [gdtptr]
        mov ax, 0x10
        mov ds, ax
        mov es, ax
        mov fs, ax
        mov gs, ax
        mov ss, ax

        jmp dword 0x08:next
next:

; Init interrupts
lidt [idtptr]
call init_idt

; Init PIC
call init_pic

; Init the Programmable interrupt controller
call init_pit

; Enable interrupts
        sti

; Jump to the kernel
push ebx
call cmain


; GDT pointer used to load the new GDT
gdtptr:
dw 0x800    ; Size
        dd 0x000    ; Address


; IDT pointer used to load IDT
idtptr:
dw 0x400    ; Size
        dd 0x800    ; Address


; Messages
hello db 'Kernel is speaking', 10, 0

/Neil Dökkalfar <[email protected]>

[bubach]

I don´t know what the problem is, but you could check on this forum:
http://www.mega-tokyo.com/forum/
You may already know about that forum, but i post the link anyway..
They are a bit more active (faster and better responses) i think...

/ Christoffer