kernel2/idt.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <idt.h>
  20 #include <isr.h>
  21 #include <malloc.h>
  22 #include <gdt.h>
  23 #include <string.h>
  24 #include <debug.h>
  25 #include <syscall.h>
  26
  27 /**
  28  * Initializes IDT
  29  *  @return 0=Success; -1=Failure
  30  */
  31 int idt_init() {
  32   int i;
  33   //idt = calloc(ISR_NUM,sizeof(idtdesc_t));
  34   memset(idt,0,ISR_NUM*sizeof(idtdesc_t));
  35
  36   selector_t selector = {
  37     .index = 1,
  38     .ti = 0,
  39     .priv = PRIV_KERNEL
  40   };
  41   for (i=0;i<ISR_NUM;i++) {
  42     idt_set_descriptor(i,isr[i],selector,i==SYSCALL_INT?PRIV_USER:PRIV_KERNEL,IDT_INTGATE32|IDT_PRESENT);
  43   }
  44
  45   idtsel_t idtsel = {
  46     .size = ISR_NUM*sizeof(idtdesc_t)-1,
  47     .offset = (uint32_t)&idt
  48   };
  49   asm("lidt (%0)"::"r"(&idtsel));
  50
  51   return 0;
  52 }
  53
  54 void idt_set_descriptor(int i,void *addr,selector_t selector,priv_t priv,int type) {
  55   idt[i].zero = 0;
  56   idt[i].address0_15 = ((unsigned int)addr)&0xFFFF;
  57   idt[i].address16_31 = (((unsigned int)addr)>>16)&0xFFFF;
  58   idt[i].selector = selector;
  59   idt[i].type = type|((priv&3)<<5);
  60 }