work

kernel/src/util/mod.rs

@@ -1 +1,3 @@
 pub mod bits;
+pub mod mutex;
+pub mod spin;

kernel/src/util/mutex.rs

@@ -0,0 +1,29 @@
+use super::spin::SpinLock;
+
+struct Mutex<T> {
+    lock: SpinLock,
+    val: T,
+}
+
+impl<T> Mutex<T> {
+    pub fn new(val: T) -> Self {
+        Self {
+            lock: SpinLock::new(),
+            val,
+        }
+    }
+    pub fn lock(&mut self) -> MutexGuard<T> {
+        self.lock.lock();
+        MutexGuard { mutex: self }
+    }
+}
+
+struct MutexGuard<'a, T> {
+    mutex: &'a mut Mutex<T>,
+}
+
+impl <'a, T> Drop for MutexGuard<'a, T> {
+    fn drop(&mut self) {
+        self.mutex.lock.unlock();
+    }
+}

kernel/src/util/spin.rs

@@ -0,0 +1,19 @@
+use core::sync::atomic::{AtomicBool, Ordering};
+
+pub struct SpinLock {
+    pub locked: AtomicBool,
+}
+
+impl SpinLock {
+    pub fn new() -> Self {
+        Self {
+            locked: AtomicBool::new(false),
+        }
+    }
+    pub fn lock(&mut self) {
+        while self.locked.swap(true, Ordering::Acquire) {}
+    }
+    pub fn unlock(&mut self) {
+        self.locked.store(false, Ordering::Release)
+    }
+}