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#include <kernel/arch/i386/gdt.h>
#include <kernel/arch/i386/interrupts/idt.h>
#include <kernel/arch/i386/interrupts/isr.h>
#include <kernel/panic.h>
#include <stdbool.h>
#include <stdint.h>
struct idt_entry {
uint16_t offset_low ;
uint16_t code_seg ;
uint8_t zero ; // unused, has to be 0
uint8_t type : 4; // 16/32 bit, task/interrupt/task gate
uint8_t storage : 1; // 0 for interrupt/trap gates
uint8_t ring : 2;
uint8_t present : 1;
uint16_t offset_high ;
} __attribute__((packed));
// is exactly the same as lgdt_arg, i should combine them into a single struct
// later
struct lidt_arg {
uint16_t limit;
uint32_t base;
} __attribute__((packed));
static struct idt_entry IDT[256];
static struct lidt_arg lidt_arg;
static inline void idt_add(uint8_t num, bool user, void (*isr));
static void idt_prepare();
static void idt_load();
static void idt_test();
static inline void idt_add(uint8_t num, bool user, void (*isr)) {
uintptr_t offset = (uintptr_t) isr;
IDT[num] = (struct idt_entry) {
.offset_low = offset,
.offset_high = offset >> 16,
.code_seg = SEG_r0code << 3,
.zero = 0,
.present = 1,
.ring = user ? 3 : 0,
.storage = 0,
.type = 0xE, // 32-bit interrupt gate
};
}
static void idt_prepare() {
for (int i = 0; i < 256; i++)
IDT[i].present = 0;
idt_add(0x08, false, isr_double_fault);
idt_add(0x0d, false, isr_general_protection_fault);
idt_add(0x0e, false, isr_page_fault);
idt_add(0x34, false, isr_test_interrupt);
}
static void idt_load() {
lidt_arg.limit = sizeof(IDT) - 1;
lidt_arg.base = (uintptr_t) &IDT;
asm("lidt (%0)" : : "r" (&lidt_arg) : "memory");
}
static void idt_test() {
asm("int $0x34" : : : "memory");
if (!isr_test_interrupt_called) panic();
}
void idt_init() {
idt_prepare();
idt_load();
idt_test();
}
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