From 5cfe5443e678e3354ed3488baea9c91cbb9e7697 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Fri, 9 Jul 2021 16:49:59 +0200
Subject: interrupt self-test

---
 kernel/idt.c | 8 +++++++-
 kernel/isr.c | 8 ++++++++
 kernel/isr.h | 6 ++++++
 3 files changed, 21 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/idt.c b/kernel/idt.c
index e1d45b9..cd032d3 100644
--- a/kernel/idt.c
+++ b/kernel/idt.c
@@ -1,6 +1,7 @@
 #include <kernel/gdt.h>
 #include <kernel/idt.h>
 #include <kernel/isr.h>
+#include <kernel/tty.h> // used only for the selftest
 #include <stdbool.h>
 #include <stdint.h>
 
@@ -51,7 +52,8 @@ static void idt_prepare() {
 	for (int i = 0; i < 256; i++)
 		IDT[i].present = 0;
 
-	idt_add(0x8, false, isr_double_fault);
+	idt_add(0x08, false, isr_double_fault);
+	idt_add(0x34, false, isr_test_interrupt);
 }
 
 static void idt_load() {
@@ -62,6 +64,10 @@ static void idt_load() {
 
 static void idt_test() {
 	asm("int $0x34" : : : "memory");
+	if (!isr_test_interrupt_called) {
+		tty_const("IDT self test failed");
+		for(;;);
+	}
 }
 
 void idt_init() {
diff --git a/kernel/isr.c b/kernel/isr.c
index 69c688b..331e9a5 100644
--- a/kernel/isr.c
+++ b/kernel/isr.c
@@ -1,9 +1,17 @@
 #include <kernel/isr.h>
 #include <kernel/tty.h>
+#include <stdbool.h>
 #include <stdint.h>
 
+bool isr_test_interrupt_called = false;
+
 __attribute__((interrupt))
 void isr_double_fault(struct interrupt_frame *frame) {
 	tty_const("#DF");
 	for(;;);
 }
+
+__attribute__((interrupt))
+void isr_test_interrupt(struct interrupt_frame *frame) {
+	isr_test_interrupt_called = true;
+}
diff --git a/kernel/isr.h b/kernel/isr.h
index 7230986..624e9ad 100644
--- a/kernel/isr.h
+++ b/kernel/isr.h
@@ -1,6 +1,12 @@
 #pragma once
+#include <stdbool.h>
 
 struct interrupt_frame;
 
+extern bool isr_test_interrupt_called; // used in the self-test in idt.c
+
 __attribute__((interrupt))
 void isr_double_fault(struct interrupt_frame *frame);
+
+__attribute__((interrupt))
+void isr_test_interrupt(struct interrupt_frame *frame);
-- 
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