/kiddie/sys/arch/i386/idt.c

/*
 * Copyright (c) 2008, Artur Emagulov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

/*
 * robot-os
 * 09.09.2008
 * idt.c -
 *
 */

#include <i386/atoms.h>
#include <i386/cpu.h>
#include <sys/types.h>

typedef void (*trapfn_t)(void);

/**
 * Global Segment descriptor
 */
static struct idt_entry idt[NIDTS];
static struct idt_ptr idtp;

/**
 * Interrupt table
 */
static const trapfn_t intr_table[] =
{
		intr_0, intr_1, intr_2,
		intr_3,	intr_4,	intr_5,
		intr_6, intr_7,	intr_8,
		intr_9,  intr_10, intr_11,
		intr_12, intr_13, intr_14,
		intr_15
};

/**
 * Trap table
 */
static const trapfn_t trap_table[] = {
		trap_0, trap_1, trap_2, trap_3,
		trap_4,	trap_5, trap_6, trap_7,
		trap_8, trap_9, trap_10, trap_11,
		trap_12,trap_13, trap_14, trap_15,
		trap_16, trap_17, trap_18 };

#define NTRAPS	(int)(sizeof(trap_table) / sizeof(void *))

/**
 * Set IDT (interrupt descriptor table) members into specified vector
 */
static void idt_set_gate(int vec, u_long base, u_short sel, u_char flags) {

    /* The interrupt routine's base address */
    idt[vec].base_lo = (base & 0xFFFF);
    idt[vec].base_hi = (base >> 16) & 0xFFFF;

    /* The segment or 'selector' that this IDT entry will use
    *  is set here, along with any access flags */
    idt[vec].selector = sel;
    idt[vec].always0 = 0;
    idt[vec].flags = flags;
}


/**
 * Setup the interrupt descriptor table and load it.
 *
 * IDT layout:
 *  0x00 - 0x12 ... S/W trap
 *  0x13 - 0x1f ... Intel reserved
 *  0x20 - 0x3f ... H/W interrupt
 *  0x40        ... System call trap
 */
void __arch_idt_init(void) {
	int i;

#if 0
	printk("Initializing IRQ's...");
	interrupt_init();
	printk("OK\n");
#endif

	printk("Lodaing IDT... ");

	idtp.limit = (u16)(sizeof(idt) - 1);
	idtp.base = (u32)&idt;

	/*memset(&idt, 0, sizeof(struct idt_entry) * 256);*/

	/* Fill all vectors with default handler */
	for (i = 0; i < NIDTS; i++)
	{
		idt_set_gate(i, (u_long)trap_default, KERNEL_CS, ST_PRESENT | ST_KERN | ST_TRAP_GATE);
	}

	/* Setup trap handlers */
	for (i = 0; i < NTRAPS; i++)
	{
		/* printk ("Setting IDT[%d] 0x%x flags[0x%x]",i,KERNEL_CS, ST_PRESENT | ST_KERN | ST_TRAP_GATE); */
		idt_set_gate(i, (u_long)trap_table[i], KERNEL_CS, ST_PRESENT | ST_KERN | ST_TRAP_GATE);
	}

	/* Setup interrupt handlers */
	for (i = 0; i < 16; i++)
	{
		/*printk ("Setting IDT[%d] 0x%x flags[0x%x]\n",0x20 + i,KERNEL_CS, ST_PRESENT | ST_KERN | ST_INTR_GATE);*/
		idt_set_gate(0x20 + i, (u_long)intr_table[i], KERNEL_CS, ST_PRESENT | ST_KERN | ST_INTR_GATE);
	}

	/* Setup debug trap */
/*	idt_set_gate(3, trap_3, KERNEL_CS, ST_USER | ST_TRAP_GATE);
*/
	/* Setup system call handler */
	idt_set_gate(SYSCALL_INT, (u_long)syscall_entry, KERNEL_CS, ST_PRESENT | ST_USER | ST_TRAP_GATE);

	/* Load IDT */
	lidt(&idtp);

	printk("OK\n");

}