Kernel: Make thread unblocking O(1)

This is still bit broken. VirtualBox seems to freeze sometimes, but I
could not recreate this on qemu (with and without kvm) or real hardware.

kernel/include/kernel/ProcessorID.h

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <BAN/Formatter.h>
+
+namespace Kernel
+{
+
+	class ProcessorID
+	{
+	public:
+		using value_type = uint32_t;
+
+	public:
+		ProcessorID() = default;
+
+		uint32_t as_u32() const { return m_id; }
+		bool operator==(ProcessorID other) const { return m_id == other.m_id; }
+
+	private:
+		explicit ProcessorID(uint32_t id) : m_id(id) {}
+
+	private:
+		uint32_t m_id = static_cast<uint32_t>(-1);
+
+		friend class Processor;
+		friend class APIC;
+	};
+
+	inline constexpr ProcessorID PROCESSOR_NONE { };
+
+}
+
+namespace BAN::Formatter
+{
+
+	template<typename F>
+	void print_argument(F putc, Kernel::ProcessorID processor_id, const ValueFormat& format)
+	{
+		print_argument(putc, processor_id.as_u32(), format);
+	}
+
+}