PIC & Interrupt Handling (#77)

* CPUID call and parse module

* Improve feature names and remove reserved features

* Begin work on PIC support

* Begin handling interrupts

* The magic call has been poofed

* Interrupt listener registry

* Remove testing code

* Make PIC private

kernel/src/interrupts/mod.rs

@@ -1,42 +1,102 @@
 //! Module for interrupt handling/IDT
 
-use x86_64::structures::idt::Idt;
+use x86_64::structures::idt::{Idt, ExceptionStackFrame};
 
-mod legacy_pic;
+use alloc::vec::Vec;
+use spin::RwLock;
+use array_init;
+
+mod pic;
 mod exceptions;
 
 lazy_static! {
     static ref IDT: Idt = {
         let mut idt = Idt::new();
-        idt.divide_by_zero.set_handler_fn(exceptions::divide_by_zero);
-        idt.breakpoint.set_handler_fn(exceptions::breakpoint);
-        idt.overflow.set_handler_fn(exceptions::overflow);
-        idt.bound_range_exceeded.set_handler_fn(exceptions::out_of_bounds);
-        idt.invalid_opcode.set_handler_fn(exceptions::invalid_opcode);
-        idt.device_not_available.set_handler_fn(exceptions::device_not_available);
-        idt.double_fault.set_handler_fn(exceptions::double_fault);
-        idt.invalid_tss.set_handler_fn(exceptions::invalid_tss);
-        idt.segment_not_present.set_handler_fn(exceptions::segment_not_present);
-        idt.stack_segment_fault.set_handler_fn(exceptions::stack_segment_fault);
-        idt.general_protection_fault.set_handler_fn(exceptions::general_protection_fault);
-        idt.page_fault.set_handler_fn(exceptions::page_fault);
-        idt.x87_floating_point.set_handler_fn(exceptions::x87_floating_point);
-        idt.alignment_check.set_handler_fn(exceptions::alignment_check);
-        idt.machine_check.set_handler_fn(exceptions::machine_check);
-        idt.simd_floating_point.set_handler_fn(exceptions::simd_floating_point);
-        idt.virtualization.set_handler_fn(exceptions::virtualization);
-        idt.security_exception.set_handler_fn(exceptions::security_exception);
+        init_interrupt_handlers(&mut idt);
         idt
     };
 }
 
-/// Implicitly invoke the lazy initializer of the IDT & load it, as well as disable PICs and set up
-/// APICs
-pub fn init() {
-    info!("interrupts: initialising");
-    debug!("interrupts: loading idt");
+lazy_static! {
+    static ref LISTENERS: RwLock<[Vec<fn()>; 16]> = RwLock::new(
+        array_init::array_init(|_| Vec::with_capacity(1))
+    );
+}
+
+/// Registers a listener for the given IRQ
+pub fn listen<I: Into<u8>>(irq: I, listener: fn()) {
+    LISTENERS.write()[irq.into() as usize].push(listener);
+}
+
+/// Dispatches the given IRQ to all relevant registered listeners
+pub fn dispatch_irq(irq: u8) {
+    for listener in LISTENERS.read()[irq as usize].iter() {
+        listener();
+    }
+}
+
+#[repr(u8)]
+pub enum Irq {
+    Pit = 0,
+    Ps2Keyboard = 1,
+    Ps2Mouse = 12,
+}
+
+impl Into<u8> for Irq {
+    fn into(self) -> u8 { self as u8 }
+}
+
+/// Setup IDTs and initialize and remap PICs
+pub fn initialize() {
+    info!("interrupts: initializing");
+
     IDT.load();
-    debug!("interrupts: disabling legacy PICs");
-    legacy_pic::CHAINED_PICS.lock().remap_and_disable();
-    info!("interrupts: initialised")
+    debug!("interrupts: initialized idt");
+
+    pic::CHAINED_PICS.lock().init_and_remap();
+    debug!("interrupts: pic initialized and remapped");
+}
+
+pub fn enable() {
+    unsafe { asm!("sti" :::: "volatile"); }
+}
+
+pub fn disable() {
+    unsafe { asm!("cli" :::: "volatile"); }
+}
+
+macro_rules! init_irq_handlers {
+    ($idt:expr, $($irq:expr),*) => {
+        $(
+            {
+                extern "x86-interrupt" fn handle_irq(_: &mut ExceptionStackFrame) {
+                    pic::CHAINED_PICS.lock().handle_interrupt($irq, || dispatch_irq($irq));
+                }
+                $idt.interrupts[$irq].set_handler_fn(handle_irq);
+            }
+        )*
+    };
+}
+
+fn init_interrupt_handlers(idt: &mut Idt) {
+    idt.divide_by_zero.set_handler_fn(exceptions::divide_by_zero);
+    idt.breakpoint.set_handler_fn(exceptions::breakpoint);
+    idt.overflow.set_handler_fn(exceptions::overflow);
+    idt.bound_range_exceeded.set_handler_fn(exceptions::out_of_bounds);
+    idt.invalid_opcode.set_handler_fn(exceptions::invalid_opcode);
+    idt.device_not_available.set_handler_fn(exceptions::device_not_available);
+    idt.double_fault.set_handler_fn(exceptions::double_fault);
+    idt.invalid_tss.set_handler_fn(exceptions::invalid_tss);
+    idt.segment_not_present.set_handler_fn(exceptions::segment_not_present);
+    idt.stack_segment_fault.set_handler_fn(exceptions::stack_segment_fault);
+    idt.general_protection_fault.set_handler_fn(exceptions::general_protection_fault);
+    idt.page_fault.set_handler_fn(exceptions::page_fault);
+    idt.x87_floating_point.set_handler_fn(exceptions::x87_floating_point);
+    idt.alignment_check.set_handler_fn(exceptions::alignment_check);
+    idt.machine_check.set_handler_fn(exceptions::machine_check);
+    idt.simd_floating_point.set_handler_fn(exceptions::simd_floating_point);
+    idt.virtualization.set_handler_fn(exceptions::virtualization);
+    idt.security_exception.set_handler_fn(exceptions::security_exception);
+
+    init_irq_handlers!(idt, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
 }