Kernel: Add basic interrupt handling

moon/Cargo.lock

@@ -8,6 +8,18 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "bit_field"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "lock_api"
 version = "0.4.9"
@@ -23,8 +35,15 @@ name = "moon"
 version = "0.1.0"
 dependencies = [
  "spin",
+ "x86_64",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97477e48b4cf8603ad5f7aaf897467cf42ab4218a38ef76fb14c2d6773a6d6a8"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -39,3 +58,21 @@ checksum = "7f6002a767bff9e83f8eeecf883ecb8011875a21ae8da43bffb817a57e78cc09"
 dependencies = [
  "lock_api",
 ]
+
+[[package]]
+name = "volatile"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3ca98349dda8a60ae74e04fd90c7fb4d6a4fbe01e6d3be095478aa0b76f6c0c"
+
+[[package]]
+name = "x86_64"
+version = "0.14.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "100555a863c0092238c2e0e814c1096c1e5cf066a309c696a87e907b5f8c5d69"
+dependencies = [
+ "bit_field",
+ "bitflags",
+ "rustversion",
+ "volatile",
+]

moon/Cargo.toml

@@ -16,4 +16,5 @@ strip = "debuginfo"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-spin = "0.9.4"
+spin = "0.9.4"
+x86_64 = "0.14.10"

moon/src/arch/interrupts.rs

@@ -0,0 +1,2 @@
+#![cfg(target_arch = "x86_64")]
+pub use super::x86_64::interrupts::*;

moon/src/arch/mod.rs

@@ -1,5 +1,6 @@
 pub mod cpu;
 pub mod io;
+pub mod interrupts;
 
 #[cfg(target_arch = "x86_64")]
 mod x86_64;

moon/src/arch/x86_64/interrupts.rs

@@ -0,0 +1,34 @@
+use x86_64::structures::idt::{InterruptDescriptorTable, InterruptStackFrame, PageFaultErrorCode};
+use crate::try_println;
+use core::arch::asm;
+
+static mut IDT: InterruptDescriptorTable = InterruptDescriptorTable::new();
+
+extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame)
+{
+    try_println!("Breakpoint!\n{:#?}", stack_frame);
+}
+
+extern "x86-interrupt" fn page_fault_handler(stack_frame: InterruptStackFrame, faulting_address: PageFaultErrorCode)
+{
+    try_println!("Page fault at {:#?}\n{:#?}", faulting_address, stack_frame);
+}
+
+pub fn load()
+{
+    unsafe { 
+        IDT.breakpoint.set_handler_fn(breakpoint_handler);
+        IDT.page_fault.set_handler_fn(page_fault_handler);
+        IDT.load(); 
+    }
+}
+
+pub fn enable()
+{
+    unsafe { asm!("sti"); }
+}
+
+pub fn disable()
+{
+    unsafe { asm!("cli"); }
+}

moon/src/arch/x86_64/mod.rs

@@ -1,3 +1,4 @@
 #![cfg(target_arch = "x86_64")]
 pub mod cpu;
-pub mod io;
+pub mod io;
+pub mod interrupts;

moon/src/init.rs

@@ -4,13 +4,13 @@ use crate::util::get_bootboot;
 use crate::arch::cpu;
 
 pub fn halt_other_cores() -> () {
-    let boot: BOOTBOOT = get_bootboot();
+    let boot: &BOOTBOOT = get_bootboot();
     if cpu::get_processor_id() != boot.bspid as u32 {
         cpu::halt();
     }
 }
 
 pub fn check_magic() -> () {
-    let boot: BOOTBOOT = get_bootboot();
+    let boot: &BOOTBOOT = get_bootboot();
     assert_eq!(boot.magic, BOOTBOOT_MAGIC[..4]);
 }

moon/src/log.rs

@@ -1,19 +1,48 @@
 use crate::arch::io::SERIAL;
 use core::fmt;
 
+/// Locks the serial port and writes formatted output.
 #[macro_export]
 macro_rules! print {
     ($($arg:tt)*) => ($crate::log::_print(format_args!($($arg)*)));
 }
 
+/// Tries to lock the serial port and writes formatted output.
+/// Should be used in interrupt handlers, as it does not block but silently fails. 
+/// (If we are blocked waiting for interrupted code to unlock a lock, that's an instant deadlock unless we are on SMP and another CPU schedules that code)
+#[macro_export]
+macro_rules! try_print {
+    ($($arg:tt)*) => ($crate::log::_try_print(format_args!($($arg)*)));
+}
+
+/// Locks the serial port and writes formatted output with a trailing newline.
 #[macro_export]
 macro_rules! println {
     () => ($crate::print!("\n"));
     ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
 }
 
+/// Tries to lock the serial port and writes formatted output with a trailing newline.
+/// Should be used in interrupt handlers, as it does not block but silently fails. 
+/// (If we are blocked waiting for interrupted code to unlock a lock, that's an instant deadlock unless we are on SMP and another CPU schedules that code)
+#[macro_export]
+macro_rules! try_println {
+    () => ($crate::try_print!("\n"));
+    ($($arg:tt)*) => ($crate::try_print!("{}\n", format_args!($($arg)*)));
+}
+
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
     SERIAL.lock().write_fmt(args).unwrap();
+}
+
+#[doc(hidden)]
+pub fn _try_print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    let serial = SERIAL.try_lock();
+    if serial.is_some()
+    {
+        serial.unwrap().write_fmt(args).unwrap();
+    }
 }

moon/src/main.rs

@@ -2,6 +2,7 @@
 #![no_main]
 
 #![feature(core_intrinsics)]
+#![feature(abi_x86_interrupt)]
 
 mod video;
 mod bootboot;
@@ -12,18 +13,31 @@ mod arch;
 mod log;
 
 use arch::cpu;
+use arch::interrupts;
+
+use x86_64::instructions::interrupts::int3;
 
 use video::Color;
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
 
+    interrupts::disable();
+
     init::halt_other_cores();
     init::check_magic();
 
+    interrupts::load();
+
     video::clear(Color::White);
 
     println!("Hello, world!");
+
+    interrupts::enable();
+
+    int3();
+
+    println!("Still here!");
     
     cpu::halt();
 

moon/src/util.rs

@@ -1,5 +1,5 @@
 use crate::bootboot::{BOOTBOOT, BOOTBOOT_INFO};
 
-pub fn get_bootboot() -> BOOTBOOT {
-    return unsafe { *(BOOTBOOT_INFO as *const BOOTBOOT) }
+pub fn get_bootboot() -> &'static BOOTBOOT {
+    return unsafe { & *(BOOTBOOT_INFO as *const BOOTBOOT) }
 }

moon/src/video.rs

@@ -39,7 +39,7 @@ impl Color {
         bswap(self as u32)
     }
 
-    fn to_layout(self, layout: u32) -> u32 {
+    fn to_data_layout(self, layout: u32) -> u32 {
         match layout {
             FB_ARGB => self.to_argb(),
             FB_BGRA => self.to_bgra(),
@@ -49,24 +49,25 @@ impl Color {
 }
 
 pub fn put_pixel(x: u32, y: u32, color: Color) -> () {
-    let boot: BOOTBOOT = get_bootboot();
+    let boot: &BOOTBOOT = get_bootboot();
     let ptr: u64 = FB + (boot.fb_scanline * y) as u64 + (x * 4) as u64;
-    unsafe { *(ptr as *mut u32) = color.to_layout(boot.fb_type as u32) };
+    unsafe { *(ptr as *mut u32) = color.to_data_layout(boot.fb_type as u32) };
 }
 
 pub fn draw_rect(x: u32, y: u32, width: u32, height: u32, color: Color) -> () {
-    let boot: BOOTBOOT = get_bootboot();
+    let boot: &BOOTBOOT = get_bootboot();
+    let col: u32 = color.to_data_layout(boot.fb_type as u32);
     for i in y..(y + height)
     {
         let addr: u64 = FB + (boot.fb_scanline * i) as u64 + (x * 4) as u64;
         for ptr in (addr..(addr + (width*4) as u64)).step_by(4)
         {
-            unsafe { *(ptr as *mut u32) = color.to_layout(boot.fb_type as u32) };
+            unsafe { *(ptr as *mut u32) = col };
         }
     }
 }
 
 pub fn clear(color: Color) -> () {
-    let boot: BOOTBOOT = get_bootboot();
+    let boot: &BOOTBOOT = get_bootboot();
     draw_rect(0, 0, boot.fb_width, boot.fb_height, color)
 }