View of xos/kernel/idt.c

/* Interrupt Descriptor Table */
/* Copyright (C) 2008  Emmanuel Varoquaux
 
   This file is part of XOS.
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
/* La IDT provisoire mise en place par le code de demarrage est vide et toute
 * exception ou interruption provoque un triple-faute-reboot. Les interruptions
 * externes sont cependant masquees pendant l'initialisation du systeme. */
 
#include <it.h>
#include <panic.h>
#include <gdt.h>
#include <system.h>
#include <system_data_structs.h>
#include <system_structs.h>
#include <asm.h>
 
static struct descr_struct idt[256];
 
/* Descripteurs */
 
static void set_interrupt_gate(unsigned int index, int dpl, void *handler)
{
  struct descr_data_struct ig_dat;
 
  ig_dat.type = 0; /* system */
  ig_dat.system_type = SDT_386INTGT; /* interrupt gate */
  ig_dat.dpl = dpl;
  ig_dat.present = 1;
  ig_dat.selector = KERNEL_CODE_SEL;
  ig_dat.offset = (unsigned long)handler;
  set_descr(&idt[index], &ig_dat);
}
 
static void set_trap_gate(unsigned int index, int dpl, void *handler)
{
  struct descr_data_struct tg_dat;
 
  tg_dat.type = 0; /* system */
  tg_dat.system_type = SDT_386TRAPGT; /* trap gate */
  tg_dat.dpl = dpl;
  tg_dat.present = 1;
  tg_dat.selector = KERNEL_CODE_SEL;
  tg_dat.offset = (unsigned long)handler;
  set_descr(&idt[index], &tg_dat);
}
 
/* Fonctions exportees */
 
void setup_idt()
{
  struct __attribute__ ((packed)) {
    unsigned short limit;
    unsigned long base;
  } idt_descr;
  unsigned int i;
 
  /* exceptions */
  for (i = 0; i <= 31; i++)
    set_interrupt_gate(i, 0, die);
 
  /* interruptions externes */
  for (i = 32; i <= 255; i++)
    set_interrupt_gate(i, 0, ignore_it); /* Available for external interrupts via INTR pin */
 
  idt_descr.limit = sizeof idt - 1;
  idt_descr.base = (unsigned long)idt;
  lidt(idt_descr);
}
 
void idt_set_trap_gate(unsigned int id, void *handler)
{
  set_trap_gate(id, 0, handler);
}
 
void idt_set_interrupt_gate(unsigned int id, void *handler)
{
  set_interrupt_gate(id, 0, handler);
}
 
void idt_set_system_gate(unsigned int id, void *handler)
{
  set_trap_gate(id, 3, handler);
}