Handle timer interrupts

Cargo.lock

@@ -8,6 +8,7 @@ version = "0.1.0"
 dependencies = [
  "bootloader",
  "lazy_static",
+ "pic8259",
  "spin",
  "volatile 0.2.7",
  "x86_64",
@@ -40,6 +41,15 @@ dependencies = [
  "spin",
 ]
 
+[[package]]
+name = "pic8259"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24ec21f514e2e16e94649f1d041ca4a7069b512c037ac156360652a775e6229d"
+dependencies = [
+ "x86_64",
+]
+
 [[package]]
 name = "spin"
 version = "0.5.2"

Cargo.toml

@@ -10,6 +10,7 @@ bootloader = "0.9.8"
 volatile = "0.2.6"
 spin = "0.5.2"
 x86_64 = "0.14.2"
+pic8259 = "0.10.1"
 
 [dependencies.lazy_static]
 version = "1.0"

src/interrupts.rs

@@ -1,7 +1,10 @@
 use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame};
 use crate::println;
+use crate::print;
 use lazy_static::lazy_static;
 use crate::gdt;
+use pic8259::ChainedPics;
+use spin::Mutex;
 
 lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
@@ -11,12 +14,16 @@ lazy_static! {
             idt.double_fault.set_handler_fn(double_fault_handler)
                 .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
         }
+        idt[InterruptIndex::Timer.as_usize()]
+            .set_handler_fn(timer_interrupt_handler);
         idt
     };
 }
 
-pub fn init_idt() {
+pub fn init() {
     IDT.load();
+    unsafe { PICS.lock().initialize() };
+    x86_64::instructions::interrupts::enable();
 }
 
 extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
@@ -26,3 +33,32 @@ extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
 extern "x86-interrupt" fn double_fault_handler(stack_frame: InterruptStackFrame, _error_code: u64) -> ! {
     panic!("EXCEPTION : DOUBLE FAULT\n{:#?}", stack_frame);
 }
+
+extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFrame) {
+    print!(".");
+
+    unsafe {
+        PICS.lock().notify_end_of_interrupt(InterruptIndex::Timer.as_u8());
+    }
+}
+
+pub const PIC_1_OFFSET: u8 = 32;
+pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
+
+pub static PICS: Mutex<ChainedPics> = Mutex::new(unsafe { ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
+
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+pub enum InterruptIndex {
+    Timer = PIC_1_OFFSET
+}
+
+impl InterruptIndex {
+    fn as_u8(self) -> u8 {
+        self as u8
+    }
+
+    fn as_usize(self) -> usize {
+        usize::from(self.as_u8())
+    }
+}

src/main.rs

@@ -21,7 +21,7 @@ fn panic(info: &PanicInfo) -> ! {
 
 fn init() {
     gdt::init_gdt();
-    interrupts::init_idt();
+    interrupts::init();
 }
 
 #[no_mangle]
@@ -32,17 +32,13 @@ pub extern "C" fn _start() {
 
     x86_64::instructions::interrupts::int3();
 
-    fn stack_overflow() {
-        stack_overflow();
-    }
-
-    stack_overflow();
-
     #[cfg(test)]
     test_main();
 
     println!("It did not crash!");
-    loop {}
+    loop {
+        x86_64::instructions::hlt();
+    }
 }
 
 #[cfg(test)]

src/vga_buffer.rs

@@ -142,5 +142,12 @@ macro_rules! println {
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
-    WRITER.lock().write_fmt(args).unwrap();
-}
+    use x86_64::instructions::interrupts;
+
+    interrupts::without_interrupts(|| {
+        WRITER.lock().write_fmt(args).unwrap();
+    }); 
+}   
+
+
+