96 lines
3.4 KiB
C
96 lines
3.4 KiB
C
/*
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* Copyright (c) 2010, Stefan Lankes, RWTH Aachen University
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* @author Stefan Lankes
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* @file arch/x86/kernel/idt.c
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* @brief Definitions and functions related to IDT
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*
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*
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* This file defines the interface for interrupts as like
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* structures to describe interrupt descriptor table entries.\n
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* See idt.h for flag definitions.
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*/
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#include <eduos/string.h>
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#include <asm/idt.h>
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/*
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* Declare an IDT of 256 entries. Although we will only use the
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* first 32 entries in this tutorial, the rest exists as a bit
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* of a trap. If any undefined IDT entry is hit, it normally
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* will cause an "Unhandled Interrupt" exception. Any descriptor
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* for which the 'presence' bit is cleared (0) will generate an
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* "Unhandled Interrupt" exception
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*/
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static idt_entry_t idt[256] = {[0 ... 255] = {0, 0, 0, 0, 0}};
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static idt_ptr_t idtp;
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void configure_idt_entry(idt_entry_t *dest_entry, size_t base,
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unsigned short sel, unsigned char flags)
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{
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/* The interrupt routine's base address */
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dest_entry->base_lo = (base & 0xFFFF);
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dest_entry->base_hi = (base >> 16) & 0xFFFF;
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/* The segment or 'selector' that this IDT entry will use
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* is set here, along with any access flags */
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dest_entry->sel = sel;
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dest_entry->always0 = 0;
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dest_entry->flags = flags;
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}
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/*
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* Use this function to set an entry in the IDT. Alot simpler
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* than twiddling with the GDT ;)
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*/
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void idt_set_gate(unsigned char num, size_t base, unsigned short sel,
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unsigned char flags)
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{
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configure_idt_entry(&idt[num], base, sel, flags);
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}
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extern void isrsyscall(void);
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/* Installs the IDT */
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void idt_install(void)
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{
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static int initialized = 0;
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if (!initialized) {
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initialized = 1;
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/* Sets the special IDT pointer up, just like in 'gdt.c' */
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idtp.limit = (sizeof(idt_entry_t) * 256) - 1;
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idtp.base = (size_t)&idt;
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/* Add any new ISRs to the IDT here using idt_set_gate */
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}
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/* Points the processor's internal register to the new IDT */
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asm volatile("lidt %0" : : "m" (idtp));
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}
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