kernel/x86/idt.cpp

   1 /*
   2 lightOS kernel
   3 Copyright (C) 2007-2009 Jörg Pfähler
   4
   5 This program is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU General Public License
   7 as published by the Free Software Foundation; either version 2
   8 of the License, or (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, write to the Free Software
  17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  18 */
  19 #include <kernel/x86_shared/idt.hpp>
  20 using namespace kernel;
  21
  22 void idt::set_interrupt_gate(   uint8_t number,
  23                                                                 interrupt_handler handler)
  24 {
  25         mIdt[number].offset0 = reinterpret_cast<uintptr_t>(handler) & 0xFFFF;
  26         mIdt[number].selector = 0x08;
  27         mIdt[number].reserved = 0;
  28         mIdt[number].flags = 0x8E;
  29         mIdt[number].offset1 = (reinterpret_cast<uintptr_t>(handler) >> 16) & 0xFFFF;
  30 }
  31 idt::interrupt_handler idt::get_interrupt_gate(uint8_t number)
  32 {
  33         uint32_t address = mIdt[number].offset0 | (mIdt[number].offset1 << 16);
  34         return reinterpret_cast<interrupt_handler>(address);
  35 }
  36 void idt::set_userspace_interrupt_gate( uint8_t number,
  37                                                                                 interrupt_handler handler)
  38 {
  39         set_interrupt_gate(number, handler);
  40         mIdt[number].flags = 0xEE;
  41 }
  42 #ifdef _LIGHTOS_V86
  43         void idt::set_task_gate(uint8_t number, uint8_t flags, uint16_t selector)
  44         {
  45                 mIdt[number].selector = selector;
  46                 mIdt[number].flags = flags;
  47         }
  48 #endif
  49 void idt::load()
  50 {
  51         struct
  52         {
  53                 uint16_t size;
  54                 uint32_t idt;
  55         } __attribute__((packed)) idtr = {2047, reinterpret_cast<uintptr_t>(&mIdt)};
  56
  57         asm volatile("lidt %0" :: "m"(idtr));
  58 }