Basic thread run routine

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

src/fs/mod.rs

@@ -65,11 +65,14 @@ impl FileSystem for VirtualFS {
             loop {
                 if let Some(fs) = map.find_exact(&path_split) {
                     // TODO, remove path prefix of the mount point
-                    return fs.borrow_mut().open(mnt_relative_path.as_str(), flags).await;
-                }
-                else {
+                    return fs
+                        .borrow_mut()
+                        .open(mnt_relative_path.as_str(), flags)
+                        .await;
+                } else {
                     let component = path_split.remove(path_split.len() - 1);
-                    mnt_relative_path = String::from("/") + component.as_str() + mnt_relative_path.as_str();
+                    mnt_relative_path =
+                        String::from("/") + component.as_str() + mnt_relative_path.as_str();
                 }
             }
         } else {

src/lib.rs

@@ -23,6 +23,9 @@ use drivers::vga::{self, Color, ColorCode};
 use multiboot2::BootInformation;
 use task::{executor::Executor, keyboard, Task};
 
+use alloc::sync::Arc;
+use core::cell::RefCell;
+
 #[alloc_error_handler]
 fn alloc_error_handler(layout: alloc::alloc::Layout) -> ! {
     panic!("Allocation error: {:?}", layout)
@@ -48,7 +51,6 @@ pub fn init(boot_info: &BootInformation) {
     memory::gdt::init_gdt();
     interrupts::init_idt();
     vga::change_color(ColorCode::new(Color::LightGreen, Color::Black));
-    println!("Init kernel main thread: {:?}", proc::thread::KERNEL_THREAD.try_lock().unwrap().id);
 }
 
 #[no_mangle]
@@ -86,6 +88,15 @@ async fn get_file() {
 
     fd.borrow_mut().close().await;
 
-    let mut thread = proc::thread::Thread::new();
-    thread.start(proc::thread::exit as u64).await;
+    let thread = Arc::new(RefCell::new(proc::thread::Thread::new(
+        proc::thread::exit as u64,
+    )));
+    proc::scheduler::SCHEDULER
+        .lock()
+        .await
+        .register(thread.clone());
+
+    unsafe {
+        (&mut*thread.as_ptr()).run();
+    }
 }

src/proc/mod.rs

@@ -1,2 +1,2 @@
-pub mod thread;
 pub mod scheduler;
+pub mod thread;

src/proc/scheduler/mod.rs

@@ -1,22 +1,40 @@
+use crate::utils::mutex::AsyncMutex;
+
 use super::thread::{Thread, ThreadId};
 
 use alloc::{collections::BTreeMap, sync::Arc};
+use core::cell::RefCell;
 use crossbeam_queue::ArrayQueue;
+use lazy_static::lazy_static;
+
+lazy_static! {
+    pub static ref SCHEDULER: AsyncMutex<Scheduler> = AsyncMutex::new(Scheduler::new());
+}
+
+pub type Threadt = Arc<RefCell<Thread>>;
 
 pub struct Scheduler {
-    threads: BTreeMap<ThreadId, Arc<Thread>>,
+    pub threads: BTreeMap<ThreadId, Threadt>,
     thread_queue: Arc<ArrayQueue<ThreadId>>,
 }
 
 impl Scheduler {
     pub fn new() -> Self {
-        Scheduler {
+        let mut res = Scheduler {
             threads: BTreeMap::new(),
             thread_queue: Arc::new(ArrayQueue::new(100)),
-        }
+        };
+        let k_thread: Thread = Thread {
+            id: ThreadId(0),
+            entry_point: 0,
+            started: true,
+            rsp: 0,
+        };
+        res.register(Arc::new(RefCell::new(k_thread)));
+        res
     }
 
-    pub fn schedule(&mut self) -> Option<Arc<Thread>> {
+    pub fn schedule(&mut self) -> Option<Threadt> {
         if let Ok(thread_id) = self.thread_queue.pop() {
             self.thread_queue.push(thread_id);
             let thread = match self.threads.get_mut(&thread_id) {
@@ -28,4 +46,14 @@ impl Scheduler {
             None
         }
     }
+
+    pub fn register(&mut self, thread: Threadt) {
+        let thread_id = thread.borrow().id;
+        if self.threads.insert(thread_id, thread).is_some() {
+            panic!("Duplicate thread ID")
+        }
+        self.thread_queue
+            .push(thread_id)
+            .expect("Thread queue full");
+    }
 }

src/proc/thread/mod.rs

@@ -1,6 +1,8 @@
 use crate::println;
 use crate::utils::mutex::AsyncMutex;
 
+use super::scheduler::SCHEDULER;
+
 use core::arch::asm;
 use core::sync::atomic::{AtomicU64, Ordering};
 
@@ -11,25 +13,10 @@ const STACK_SIZE: usize = 4096 * 20;
 
 lazy_static! {
     pub static ref RUNNING_THREAD: AsyncMutex<ThreadId> = AsyncMutex::new(ThreadId(0));
-    pub static ref KERNEL_THREAD: AsyncMutex<Thread> = {
-        let k_rsp: u64;
-        unsafe {
-            asm!(
-                "push rsp",    // Recover current rsp
-                "pop {out}",
-                out = out(reg) k_rsp, // Save current rsp
-            );
-        }
-        let thread: Thread = Thread {
-            id: ThreadId(0),
-            rsp: k_rsp,
-        };
-        AsyncMutex::new(thread)
-    };
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
-pub struct ThreadId(u64);
+pub struct ThreadId(pub u64);
 
 impl ThreadId {
     fn new() -> Self {
@@ -39,28 +26,57 @@ impl ThreadId {
 }
 
 pub fn exit() {
-    println!("Exiting");
-    KERNEL_THREAD.try_lock().unwrap().run();
+    println!("Exiting thread");
+    let mut scheduler = SCHEDULER.try_lock().unwrap();
+    let mut thread = scheduler
+        .threads
+        .get_mut(&ThreadId(0))
+        .unwrap()
+        .borrow_mut();
+    SCHEDULER.force_unlock();
+    thread.run();
 }
 
 pub struct Thread {
     pub id: ThreadId,
-    rsp: u64
+    pub entry_point: u64,
+    pub started: bool,
+    pub rsp: u64,
 }
 
 impl Thread {
-    pub fn new() -> Self {
+    pub fn new(entry_point: u64) -> Self {
         unsafe {
             Thread {
                 id: ThreadId::new(),
+                entry_point: entry_point,
+                started: false,
                 rsp: alloc(Layout::new::<[u8; STACK_SIZE]>()) as u64 + STACK_SIZE as u64 - 0x80,
             }
         }
     }
 
-    pub async fn start(&mut self, rip: u64) {
+    pub fn run(&mut self) {
+        println!("Running thread {:?}", self.id);
         unsafe {
-            *RUNNING_THREAD.lock().await = self.id;
+            let mut current_thread_guard = RUNNING_THREAD.try_lock().unwrap();
+            let current_rsp: u64;
+            asm!(
+                "push rsp",    // Recover current rsp
+                "pop {out}",
+                "sub {out}, 56", // Offset to saved registers
+                out = out(reg) current_rsp, // Save thread rsp
+            );
+
+            let mut scheduler = SCHEDULER.try_lock().unwrap();
+            let current_thread = scheduler.threads.get_mut(&*current_thread_guard).unwrap();
+            current_thread.borrow_mut().rsp = current_rsp;
+
+            *current_thread_guard = self.id; // change running thread
+        } // The scheduler and running thread guards is dropped here
+
+        unsafe {
+            if self.started {
                 asm!(
                     "push rax",       // Save current thread regs
                     "push rbx",
@@ -70,40 +86,6 @@ impl Thread {
                     "push rsi",
                     "push rdi",
 
-                "push rsp",    // Recover current rsp
-                "pop {out}",
-                out = out(reg) KERNEL_THREAD.lock().await.rsp, // Save current rsp
-            );
-
-            asm!(
-                "push {rsp}",
-                "pop rsp",
-                "jmp {rip}",
-                rsp = in(reg) self.rsp,
-                rip = in(reg) rip,
-            );
-        }
-    }
-
-    pub async fn run(&mut self) {
-        unsafe {
-            asm!(
-                "push rax",       // Save current thread regs
-                "push rbx",
-                "push rcx",
-                "push rdx",
-                "push rbp",
-                "push rsi",
-                "push rdi",
-
-                "push rsp",    // Recover current rsp
-                "pop {out}",
-                out = out(reg) KERNEL_THREAD.lock().await.rsp, // Save current rsp
-            );
-
-            *RUNNING_THREAD.lock().await = self.id; // change running thread
-
-            asm!(
                     "push {rsp}", // Set stack pointer to the new thread
                     "pop rsp",
 
@@ -116,6 +98,24 @@ impl Thread {
                     "pop rax",
                     rsp = in(reg) self.rsp,
                 );
+            } else {
+                self.started = true;
+                asm!(
+                    "push rax",       // Save current thread regs
+                    "push rbx",
+                    "push rcx",
+                    "push rdx",
+                    "push rbp",
+                    "push rsi",
+                    "push rdi",
+
+                    "push {rsp}",
+                    "pop rsp",
+                    "jmp {rip}",
+                    rsp = in(reg) self.rsp,
+                    rip = in(reg) self.entry_point,
+                );
+            }
         }
     }
 }

src/utils/mutex.rs

@@ -80,6 +80,10 @@ impl<T> AsyncMutex<T> {
         }
     }
 
+    pub fn force_unlock(&self) {
+        self.lock.drop();
+    }
+
     pub async fn lock(&self) -> AsyncMutexGuard<'_, T> {
         self.lock.clone().await;
         AsyncMutexGuard { mutex: self }