feat(kdbg): for serial debugging

Signed-off-by: Anhad Singh <[email protected]>

src/aero_kernel/src/drivers/uart_16550.rs

@@ -20,10 +20,15 @@ use core::fmt::Write;
 
 use spin::Once;
 
+use crate::arch::interrupts::{self, InterruptStack};
 use crate::arch::io;
+use crate::userland::task::Task;
 use crate::utils::sync::Mutex;
 
-static COM_1: Once<Mutex<SerialPort>> = Once::new();
+use alloc::sync::Arc;
+use alloc::vec::Vec;
+
+pub static COM_1: Once<Mutex<SerialPort>> = Once::new();
 
 bitflags::bitflags! {
     pub struct InterruptEnable: u8 {
@@ -95,25 +100,35 @@ impl SerialPort {
     }
 
     pub fn send_byte(&mut self, byte: u8) {
-        unsafe {
-            match byte {
-                8 | 0x7F => {
-                    self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+        match byte {
+            8 | 0x7F => {
+                self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                unsafe {
                     io::outb(self.0, 8);
+                }
 
-                    self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                unsafe {
                     io::outb(self.0, b' ');
+                }
 
-                    self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                unsafe {
                     io::outb(self.0, 8);
                 }
-                _ => {
-                    self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
-                    io::outb(self.0, byte)
+            }
+            _ => {
+                self.wait_for_line_status(LineStatus::OUTPUT_EMPTY);
+                unsafe {
+                    io::outb(self.0, byte);
                 }
             }
         }
     }
+
+    pub fn read_byte(&mut self) -> u8 {
+        unsafe { io::inb(self.0) }
+    }
 }
 
 impl fmt::Write for SerialPort {
@@ -126,15 +141,44 @@ impl fmt::Write for SerialPort {
     }
 }
 
+fn irq_handler(_stack: &mut InterruptStack) {
+    if !unsafe { COM_1.get_unchecked() }
+        .lock_irq()
+        .line_status()
+        .contains(LineStatus::INPUT_FULL)
+    {
+        return;
+    }
+
+    (*LISTENERS)
+        .lock_irq()
+        .iter()
+        .for_each(|task| task.wake_up());
+}
+
+lazy_static::lazy_static! {
+    static ref LISTENERS: Mutex<Vec<Arc<Task>>> = Mutex::new(Vec::new());
+}
+
+pub fn register_listener(task: Arc<Task>) {
+    (*LISTENERS).lock_irq().push(task);
+}
+
 /// Initialize the serial ports if available.
 pub fn init() {
     unsafe {
-        let com_1 = SerialPort::new(0x3F8).init();
-
+        let com_1 = SerialPort::new(0x3f8).init();
         COM_1.call_once(move || Mutex::new(com_1));
     }
 }
 
+pub fn setup_interrupts() {
+    let vector = interrupts::allocate_vector();
+    interrupts::register_handler(vector, irq_handler);
+
+    crate::arch::apic::io_apic_setup_legacy_irq(4, vector, 1);
+}
+
 pub macro serial_print($($arg:tt)*) {
     crate::drivers::uart_16550::_serial_print(format_args!($($arg)*))
 }
@@ -147,6 +191,8 @@ pub macro serial_println {
 #[doc(hidden)]
 pub fn _serial_print(args: fmt::Arguments) {
     if let Some(c) = COM_1.get() {
-        c.lock().write_fmt(args).expect("failed to write to COM1")
+        c.lock_irq()
+            .write_fmt(args)
+            .expect("failed to write to COM1")
     }
 }

src/aero_kernel/src/main.rs

@@ -49,8 +49,7 @@
     associated_type_defaults,
     trait_upcasting,
     asm_const,
-    sync_unsafe_cell,
-    // effects
+    sync_unsafe_cell
 )]
 // TODO(andypython): can we remove the dependency of "prelude_import" and "lang_items"?
 //     `lang_items`     => is currently used for the personality function (`rust_eh_personality`).
@@ -171,7 +170,9 @@ fn aero_main() -> ! {
     // Now that all of the essential initialization is done we are going to schedule
     // the kernel main thread.
     let init = Task::new_kernel(kernel_main_thread, true);
+    let kdbg = Task::new_kernel(kernel_dbg_thread, true);
     scheduler::get_scheduler().register_task(init);
+    scheduler::get_scheduler().register_task(kdbg);
 
     unsafe {
         interrupts::enable_interrupts();
@@ -212,6 +213,62 @@ fn kernel_main_thread() {
     unreachable!()
 }
 
+fn kernel_dbg_thread() {
+    use core::fmt::Write;
+
+    use crate::drivers::uart::{self, LineStatus, COM_1};
+    use crate::userland::task::TaskId;
+    use crate::utils::sync::WaitQueue;
+
+    uart::setup_interrupts();
+
+    let input_wq = WaitQueue::new();
+    let this_task = scheduler::current_thread();
+    uart::register_listener(this_task.clone());
+
+    let com_1 = COM_1.get().unwrap();
+
+    loop {
+        let mut input = String::new();
+
+        loop {
+            let mut com_1 = input_wq
+                .block_on(com_1, |com_1| {
+                    com_1.line_status().contains(LineStatus::INPUT_FULL)
+                })
+                .unwrap();
+
+            let c = com_1.read_byte() as char;
+
+            if c == '\r' {
+                writeln!(com_1).unwrap();
+                break;
+            }
+
+            input.push(c);
+            write!(com_1, "{c}").unwrap();
+        }
+
+        let mut commands = input.split_whitespace();
+
+        if let Some(name) = commands.next() {
+            match name {
+                "ps" => scheduler::get_scheduler().log_ptable(),
+                "wake" => {
+                    log::warn!("kdbg: forcefully waking up task");
+                    let id = commands.next().unwrap().parse::<usize>().unwrap();
+                    scheduler::get_scheduler()
+                        .find_task(TaskId::new(id))
+                        .unwrap()
+                        .wake_up();
+                }
+
+                _ => log::warn!("kdbg: unknown command {name:?}"),
+            }
+        }
+    }
+}
+
 extern "C" fn aero_ap_main(ap_id: usize) -> ! {
     log::info!("AP{}: Loaded userland", ap_id);