/* * Copyright (c) 2010, Stefan Lankes, RWTH Aachen University * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** * @author Stefan Lankes * @file arch/x86/include/asm/idt.h * @brief Definition of IDT flags and functions to set interrupts * * This file contains define-constants for interrupt flags * and installer functions for interrupt gates.\n * See idt.c for structure definitions. */ #ifndef __ARCH_IDT_H__ #define __ARCH_IDT_H__ #include /// This bit shall be set to 0 if the IDT slot is empty #define IDT_FLAG_PRESENT 0x80 /// Interrupt can be called from within RING0 #define IDT_FLAG_RING0 0x00 /// Interrupt can be called from within RING1 and lower #define IDT_FLAG_RING1 0x20 /// Interrupt can be called from within RING2 and lower #define IDT_FLAG_RING2 0x40 /// Interrupt can be called from within RING3 and lower #define IDT_FLAG_RING3 0x60 /// Size of gate is 16 bit #define IDT_FLAG_16BIT 0x00 /// Size of gate is 32 bit #define IDT_FLAG_32BIT 0x08 /// The entry describes an interrupt gate #define IDT_FLAG_INTTRAP 0x06 /// The entry describes a trap gate #define IDT_FLAG_TRAPGATE 0x07 /// The entry describes a task gate #define IDT_FLAG_TASKGATE 0x05 /* * This is not IDT-flag related. It's the segment selectors for kernel code and data. */ #define KERNEL_CODE_SELECTOR 0x08 #define KERNEL_DATA_SELECTOR 0x10 #ifdef __cplusplus extern "C" { #endif /** @brief Defines an IDT entry * * This structure defines interrupt descriptor table entries.\n * They consist of the handling function's base address, some flags * and a segment selector. */ typedef struct { /// Handler function's lower 16 address bits uint16_t base_lo; /// Handler function's segment selector. uint16_t sel; /// These bits are reserved by Intel uint8_t always0; /// These 8 bits contain flags. Exact use depends on the type of interrupt gate. uint8_t flags; /// Higher 16 bits of handler function's base address uint16_t base_hi; } __attribute__ ((packed)) idt_entry_t; /** @brief Defines the idt pointer structure. * * This structure keeps information about * base address and size of the interrupt descriptor table. */ typedef struct { /// Size of the IDT in bytes (not the number of entries!) uint16_t limit; /// Base address of the IDT size_t base; } __attribute__ ((packed)) idt_ptr_t; /** @brief Installs IDT * * The installation involves the following steps: * - Set up the IDT pointer * - Set up int 0x80 for syscalls * - process idt_load() */ void idt_install(void); /** @brief Set an entry in the IDT * * @param num index in the IDT * @param base base-address of the handler function being installed * @param sel Segment the IDT will use * @param flags Flags this entry will have */ void idt_set_gate(unsigned char num, size_t base, unsigned short sel, unsigned char flags); /** @brief Configures and returns a IDT entry with chosen attributes * * Just feed this function with base, selector and the flags * you have seen in idt.h * * @return a preconfigured idt descriptor */ void configure_idt_entry(idt_entry_t *dest_entry, size_t base, unsigned short sel, unsigned char flags); #ifdef __cplusplus } #endif #endif