kernel: semaphores

kernel-src/include/semaphore.h

@@ -0,0 +1,28 @@
+#ifndef _SEMAPHORE_H
+#define _SEMAPHORE_H
+
+#include <stdbool.h>
+#include <spinlock.h>
+#include <kernel/scheduler.h>
+
+#define SEM_TAIL 0
+#define SEM_HEAD 1
+
+typedef struct {
+	int i;
+	spinlock_t lock;
+	thread_t *tail;
+	thread_t *head;
+} semaphore_t;
+
+#define SEMAPHORE_INIT(x, v) { \
+		(x)->val = v; \
+		SPINLOCK_INIT((x)->lock); \
+		(x)->list = NULL; \
+	}
+
+int semaphore_wait(semaphore_t *sem, bool interruptible);
+void semaphore_signal(semaphore_t *sem);
+bool semaphore_test(semaphore_t *sem);
+
+#endif