add todos

Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>

src/interrupts/mod.rs

@@ -53,7 +53,41 @@ extern "x86-interrupt" fn breakpoint_handler(stack_frame: InterruptStackFrame) {
 }
 
 extern "x86-interrupt" fn syscall_handler_32(_stack_frame: InterruptStackFrame) {
+    let rax: u64;
+    let rbx: u64;
+    let rcx: u64;
+    let rdx: u64;
+    let rsi: u64;
+    let rdi: u64;
+    let rbp: u64;
+    unsafe {
+        asm!(
+            "push rax",
+            "push rbx",
+            "push rcx",
+            "push rdx",
+            "push rsi",
+            "push rdi",
+            "push rbp",
+
+            "pop {rbp}",
+            "pop {rdi}",
+            "pop {rsi}",
+            "pop {rdx}",
+            "pop {rcx}",
+            "pop {rbx}",
+            "pop {rax}",
+            rax = out(reg) rax,
+            rbx = out(reg) rbx,
+            rcx = out(reg) rcx,
+            rdx = out(reg) rdx,
+            rsi = out(reg) rsi,
+            rdi = out(reg) rdi,
+            rbp = out(reg) rbp,
+        )
+    }
     println!("Received syscall");
+    crate::syscalls::syscall_routine(rax);
 }
 
 extern "x86-interrupt" fn page_fault_handler(

src/interrupts/pic/pit.rs

@@ -9,6 +9,7 @@ pub fn gettick() -> u64 {
 }
 
 pub extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFrame) {
+    // TODO: thread preemption
     unsafe {
         TICKS += 1;
         PICS.lock()

src/proc/scheduler/mod.rs

@@ -1,3 +1,4 @@
+use crate::println;
 use crate::utils::mutex::AsyncMutex;
 
 use super::thread::{Thread, ThreadId};
@@ -14,6 +15,7 @@ use futures_util::task::AtomicWaker;
 use lazy_static::lazy_static;
 
 lazy_static! {
+    // TODO: put this in a spin mutex instead
     pub static ref SCHEDULER: AsyncMutex<Scheduler> = AsyncMutex::new(Scheduler::new());
 }
 
@@ -22,8 +24,9 @@ pub type Threadt = Arc<RefCell<Thread>>;
 pub const K_THREAD_ID: ThreadId = ThreadId(0); // Kernel main thread identifier
 
 struct ThreadStream {
+    // TODO: add the double scheduler queue
     ids: ArrayQueue<ThreadId>,
-    waker: AtomicWaker
+    waker: AtomicWaker,
 }
 
 impl ThreadStream {
@@ -35,9 +38,7 @@ impl ThreadStream {
     }
 
     pub fn register(&mut self, id: ThreadId) {
-        self.ids
+        self.ids.push(id).expect("Thread queue full");
-            .push(id)
-            .expect("Thread queue full");
         self.waker.wake();
     }
 }
@@ -79,19 +80,29 @@ impl Scheduler {
             started: true,
             rsp: 0,
             base_stack: 0,
+            is_blocked: false,
         };
         res.register(Arc::new(RefCell::new(k_thread)));
         res
     }
 
-
     pub async fn run(&mut self) {
         while let Some(id) = self.thread_queue.next().await {
-            if let Some(thread) = self.get_thread(id) { // Thread still exists
+            if let Some(thread) = self.get_thread(id) {
-                unsafe {
+                // Thread still exists
-                    (&mut*thread.as_ptr()).run();
+                let blocked: bool;
+                {
+                    blocked = thread.borrow().is_blocked;
+                } // Drop thread borrow
+                if !blocked {
+                    unsafe {
+                        (&mut *thread.as_ptr()).run();
+                    }
+
+                    if !thread.borrow().is_blocked {
+                        self.thread_queue.register(id);
+                    }
                 }
-                self.thread_queue.register(id);
             }
         }
     }
@@ -106,6 +117,21 @@ impl Scheduler {
         }
     }
 
+    pub fn block(&mut self, id: ThreadId) {
+        if let Some(thread) = self.get_thread(id) {
+            thread.borrow_mut().is_blocked = true;
+            println!("Blocked thread {:?}", id);
+        }
+    }
+
+    pub fn unblock(&mut self, id: ThreadId) {
+        if let Some(thread) = self.get_thread(id) {
+            thread.borrow_mut().is_blocked = false;
+            self.thread_queue.register(id);
+            println!("Unblocked thread {:?}", id);
+        }
+    }
+
     pub fn exit(&mut self, id: ThreadId) {
         self.threads.remove(&id).unwrap().borrow().exit();
     }

src/proc/thread/mod.rs

@@ -1,7 +1,7 @@
 use crate::println;
 use crate::utils::mutex::AsyncMutex;
 
-use super::scheduler::{SCHEDULER, K_THREAD_ID};
+use super::scheduler::{K_THREAD_ID, SCHEDULER};
 
 use core::arch::asm;
 use core::sync::atomic::{AtomicU64, Ordering};
@@ -25,34 +25,22 @@ impl ThreadId {
     }
 }
 
-pub fn exit() {
-    println!("Exiting thread");
-    {
-        let mut scheduler = SCHEDULER.try_lock().unwrap();
-        scheduler.exit(*RUNNING_THREAD.try_lock().unwrap());
-    } // Drop scheduler mutex guard
-
-    resume_k_thread();
-}
-
 pub fn resume_k_thread() {
     let k_thread: *mut Thread;
     {
         let mut scheduler = SCHEDULER.try_lock().unwrap();
-        k_thread = scheduler
+        k_thread = scheduler.get_thread(K_THREAD_ID).unwrap().as_ptr();
-            .get_thread(K_THREAD_ID)
-            .unwrap()
-            .as_ptr();
     } // Drop scheduler mutex guard
 
     unsafe {
-        (&mut* k_thread).run();
+        (&mut *k_thread).run();
     }
 }
 
 pub fn routine() {
     println!("Routine executed");
-    exit();
+    crate::syscalls::syscall_routine(crate::syscalls::EXIT_ID); // Call exit
+    println!("SHOULD NEVER BE DISPLAYED");
 }
 
 pub struct Thread {
@@ -60,7 +48,8 @@ pub struct Thread {
     pub entry_point: u64,
     pub started: bool,
     pub rsp: u64,
-    pub base_stack: u64
+    pub base_stack: u64,
+    pub is_blocked: bool,
 }
 
 impl Thread {
@@ -73,13 +62,17 @@ impl Thread {
                 started: false,
                 rsp: stack_bottom + STACK_SIZE as u64,
                 base_stack: stack_bottom,
+                is_blocked: false
             }
         }
     }
 
     pub fn exit(&self) {
         unsafe {
-            dealloc(self.base_stack as *mut u8, Layout::new::<[u8; STACK_SIZE]>());
+            dealloc(
+                self.base_stack as *mut u8,
+                Layout::new::<[u8; STACK_SIZE]>(),
+            );
         }
     }
 
@@ -98,8 +91,8 @@ impl Thread {
                     out = out(reg) current_rsp, // Save thread rsp
                 );
                 current_thread.borrow_mut().rsp = current_rsp;
-            }
+            } else {
-            else { // Thread does not exists anymore
+                // Thread does not exists anymore
                 *current_thread_guard = self.id; // change running thread
                 asm!( // Just switch to new thead without saving registers
                     "push {rsp}", // Set stack pointer to the new thread

src/syscalls/ids.rs

@@ -0,0 +1,3 @@
+pub type SyscallId = u64;
+
+pub const EXIT_ID: SyscallId = 0;

src/syscalls/mod.rs

@@ -1,5 +1,60 @@
-pub mod io;
+use crate::println;
+use crate::proc::thread::{resume_k_thread, RUNNING_THREAD};
+use crate::proc::scheduler::SCHEDULER;
+use crate::task::yield_executor::YieldExecutor;
+use crate::task::Task;
 
-pub fn syscall_dispatcher() -> u64 {
+pub use ids::*;
-    0
+
+use alloc::sync::Arc;
+use core::cell::RefCell;
+
+pub mod ids;
+pub mod io;
+pub mod proc;
+
+pub type SyscallContextT = Arc<RefCell<SyscallContext>>;
+
+pub struct SyscallContext {
+    id: SyscallId,
+    res: u64,
+    thread_id: crate::proc::thread::ThreadId,
 }
+
+impl SyscallContext {
+    pub async fn run(&mut self) {
+        println!("Running async syscall runner for {:?}", self.id);
+        self.dispatch().await;
+    }
+
+    pub async fn dispatch(&mut self) {
+        match self.id {
+            EXIT_ID => proc::exit(self).await,
+            _ => bad_syscall().await,
+        }
+    }
+}
+
+
+async fn syscall_runner(context: SyscallContextT) {
+    context.borrow_mut().run().await;
+}
+
+pub fn syscall_routine(syscall_id: SyscallId) -> u64 {
+    println!("Running syscall interrupt handler");
+    let context: SyscallContextT = Arc::new(RefCell::new(SyscallContext {
+        id: syscall_id,
+        res: 0,
+        thread_id: *RUNNING_THREAD.try_lock().unwrap(),
+    }));
+    
+    println!("Spawning async syscall runner");
+    let mut executor = YieldExecutor::new(context.borrow().thread_id);
+    executor.spawn(Task::new(syscall_runner(context.clone())));
+    executor.run();
+
+    let res = context.borrow().res;
+    res
+}
+
+async fn bad_syscall() {}

src/syscalls/proc.rs

@@ -0,0 +1,11 @@
+use crate::println;
+use crate::proc::scheduler::SCHEDULER;
+use crate::proc::thread::resume_k_thread;
+
+use super::SyscallContext;
+
+pub async fn exit(context: &SyscallContext) {
+    println!("Running exit(2)");
+    SCHEDULER.lock().await.exit(context.thread_id);
+    resume_k_thread();
+}

src/task/mod.rs

@@ -5,6 +5,7 @@ use core::sync::atomic::{AtomicU64, Ordering};
 use core::task::{Context, Poll};
 
 pub mod executor;
+pub mod yield_executor;
 pub mod keyboard;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]

src/task/yield_executor.rs

@@ -0,0 +1,119 @@
+
+use crate::println;
+use crate::proc::thread::{ThreadId, resume_k_thread};
+use crate::proc::scheduler::SCHEDULER;
+
+use super::{Task, TaskId};
+
+use alloc::{collections::BTreeMap, sync::Arc, task::Wake};
+use core::task::{Context, Poll, Waker};
+use crossbeam_queue::ArrayQueue;
+
+pub struct YieldExecutor {
+    tasks: BTreeMap<TaskId, Task>,
+    task_queue: Arc<ArrayQueue<TaskId>>,
+    waker_cache: BTreeMap<TaskId, Waker>,
+    thread_id: ThreadId,
+}
+
+impl YieldExecutor {
+    pub fn new(thread_id: ThreadId) -> Self {
+        YieldExecutor {
+            tasks: BTreeMap::new(),
+            task_queue: Arc::new(ArrayQueue::new(100)),
+            waker_cache: BTreeMap::new(),
+            thread_id: thread_id,
+        }
+    }
+
+    pub fn run(&mut self) {
+        loop {
+            self.run_ready_tasks();
+            if self.done() {
+                break;
+            } else {
+                println!("Blocking thread");
+                SCHEDULER
+                    .try_lock()
+                    .unwrap()
+                    .block(self.thread_id);
+                println!("Returning to scheduler");
+                resume_k_thread();
+            }
+        }
+    }
+
+    fn done(&self) -> bool {
+        self.tasks.is_empty()
+    }
+
+    pub fn spawn(&mut self, task: Task) {
+        let task_id = task.id;
+        if self.tasks.insert(task.id, task).is_some() {
+            panic!("Duplicate task ID");
+        }
+        self.task_queue.push(task_id).expect("Task queue full");
+    }
+
+    fn run_ready_tasks(&mut self) {
+        let Self {
+            tasks,
+            task_queue,
+            waker_cache,
+            thread_id,
+        } = self; // Executor destructuring
+
+        while let Ok(task_id) = task_queue.pop() {
+            let task = match tasks.get_mut(&task_id) {
+                Some(task) => task,
+                None => continue, // Task does not exist anymore
+            };
+            let waker = waker_cache
+                .entry(task_id)
+                .or_insert_with(|| YieldTaskWaker::new(task_id, task_queue.clone(), *thread_id));
+            let mut context = Context::from_waker(waker);
+            match task.poll(&mut context) {
+                Poll::Ready(()) => {
+                    // task is done
+                    tasks.remove(&task_id);
+                    waker_cache.remove(&task_id);
+                }
+                Poll::Pending => {}
+            }
+        }
+    }
+}
+
+struct YieldTaskWaker {
+    task_id: TaskId,
+    task_queue: Arc<ArrayQueue<TaskId>>,
+    thread_id: ThreadId,
+}
+
+impl YieldTaskWaker {
+    fn new(task_id: TaskId, task_queue: Arc<ArrayQueue<TaskId>>, thread_id: ThreadId) -> Waker {
+        Waker::from(Arc::new(YieldTaskWaker {
+            task_id,
+            task_queue,
+            thread_id
+        }))
+    }
+
+    fn wake_task(&self) {
+        self.task_queue.push(self.task_id).expect("Task queue full");
+        SCHEDULER
+            .try_lock()
+            .unwrap()
+            .unblock(self.thread_id);
+    }
+}
+
+impl Wake for YieldTaskWaker {
+    fn wake(self: Arc<Self>) {
+        self.wake_task();
+    }
+
+    fn wake_by_ref(self: &Arc<Self>) {
+        self.wake_task();
+    }
+}

src/utils/mutex.rs

@@ -11,6 +11,7 @@ use futures_util::task::AtomicWaker;
 #[derive(Clone)]
 struct Lock {
     lock: Arc<AtomicBool>,
+    // TODO: Make a queue of wakers
     waker: Arc<AtomicWaker>,
 }