k-tana-zero/k/idt.c

#include "idt.h"
#include "io.h"
#include "pic/keyboard.h"
#include "pic/pic.h"
#include "pic/pit.h"
#include "stdio.h"

static struct idt idt = { 0 };

static struct idt_entry_info infos[] = {
    // Intel-defined (0-20)
    {int_de, INTERRUPT_TYPE},   {int_db, INTERRUPT_TYPE},
    {int_nmi, INTERRUPT_TYPE},  {int_bp, TRAP_TYPE},
    {int_of, TRAP_TYPE},        {int_br, INTERRUPT_TYPE},
    {int_ud, INTERRUPT_TYPE},   {int_nm, INTERRUPT_TYPE},
    {int_df, INTERRUPT_TYPE},   {0, INTERRUPT_TYPE},
    {int_ts, INTERRUPT_TYPE},   {int_np, INTERRUPT_TYPE},
    {int_ss, INTERRUPT_TYPE},   {int_gp, INTERRUPT_TYPE},
    {int_pf, INTERRUPT_TYPE},   {0, INTERRUPT_TYPE},
    {int_mf, INTERRUPT_TYPE},   {int_ac, INTERRUPT_TYPE},
    {int_mc, INTERRUPT_TYPE},   {int_xm, INTERRUPT_TYPE},
    {int_ve, INTERRUPT_TYPE},

    // Intel-reserved (21-31)
    {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},
    {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0}, {0, 0},

    // user-defined (32-255)
    {pic_pit, INTERRUPT_TYPE},    {pic_keyboard, INTERRUPT_TYPE}
};

void handle_interrupt(struct int_args *args)
{
    switch (args->int_code)
    {
        case 32: // PIT
            pit_handler();
            outb(MASTER_PORT_A, OCW2_EOI);
            return;
        case 33: // keyboard
            keyboard_handler();
            outb(MASTER_PORT_A, OCW2_EOI);
            return;
    }

    printf("INTERRUPT: %d, error code: %d\r\n", args->int_code, args->err_code);

    asm volatile("cli; hlt");
}

static struct idt_entry create_idt_entry(uint32_t offset,
                                         struct segment_selector selector,
                                         uint32_t type)
{
    struct idt_entry res = { 0 };

    res.selector = selector;
    res.offset_1 = offset & 0xffff;
    res.offset_2 = (offset >> 16) & 0xffff;

    res.type = type;
    res.size = 1;
    res.desc_priv = 0;
    res.present = 1;

    return res;
}

static void create_idt(void)
{
    struct segment_selector selector;
    selector.rpl = 0;
    selector.table_indicator = 0;
    selector.index = KERNEL_CS_INDEX;
    for (int i = 0; i < IDT_NB_ENTRIES; ++i)
    {
        struct idt_entry entry = create_idt_entry((uint32_t)infos[i].isr,
                                                  selector,
                                                  infos[i].type);
        idt.entries[i] = entry;
    }
}

static void load_idt(void)
{
    struct idt_r idtr;
    idtr.addr = (uint32_t)&idt;
    idtr.limit = IDT_SIZE - 1;

    asm volatile("lidt %0\n"
                 :
                 : "m" (idtr)
                 : "memory");
}

void init_idt(void)
{
    create_idt();
    load_idt();
}