Kernel: Add Semaphore to block threads

kernel/include/kernel/Input/PS2Keyboard.h

@@ -4,6 +4,7 @@
 #include <kernel/Input/KeyEvent.h>
 #include <kernel/Input/PS2Controller.h>
 #include <kernel/Input/PS2Keymap.h>
+#include <kernel/Semaphore.h>
 
 namespace Kernel::Input
 {
@@ -60,6 +61,8 @@ namespace Kernel::Input
 
 		State m_state { State::Normal };
 
+		Semaphore m_semaphore;
+
 		BAN::String m_name;
 
 	public:

kernel/include/kernel/Scheduler.h

@@ -2,6 +2,7 @@
 
 #include <BAN/LinkedList.h>
 #include <BAN/Memory.h>
+#include <kernel/Semaphore.h>
 #include <kernel/Thread.h>
 
 namespace Kernel
@@ -21,6 +22,9 @@ namespace Kernel
 		void set_current_thread_sleeping(uint64_t);
 		[[noreturn]] void set_current_thread_done();
 
+		void block_current_thread(Semaphore*);
+		void unblock_threads(Semaphore*);
+
 		BAN::RefPtr<Thread> current_thread();
 
 	private:
@@ -47,9 +51,18 @@ namespace Kernel
 			uint64_t wake_time;
 		};
 
+		struct BlockingThread
+		{
+			BlockingThread(const BAN::RefPtr<Thread>& thread, Semaphore* semaphore) : thread(thread), semaphore(semaphore) {}
+			BAN::RefPtr<Thread> thread;
+			Semaphore* semaphore;
+			uint8_t padding[sizeof(uint64_t) - sizeof(Semaphore*)];
+		};
+
 		BAN::RefPtr<Thread> m_idle_thread;
 		BAN::LinkedList<ActiveThread> m_active_threads;
 		BAN::LinkedList<SleepingThread> m_sleeping_threads;
+		BAN::LinkedList<BlockingThread> m_blocking_threads;
 
 		BAN::LinkedList<ActiveThread>::iterator m_current_thread;
 

kernel/include/kernel/Semaphore.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <kernel/SpinLock.h>
+
+namespace Kernel
+{
+
+	class Semaphore
+	{
+	public:
+		void block();
+		void unblock();
+		bool is_blocked() const { return m_blocked; }
+
+	private:
+		void set_blocked(bool blocked) { m_blocked = blocked; }
+
+	private:
+		bool m_blocked { false };
+
+		friend class Scheduler;
+	};
+
+}