Kernel: Save BSB id

kernel/include/kernel/Processor.h

@@ -31,11 +31,12 @@ namespace Kernel
 			asm volatile("movw %%gs, %0" : "=rm"(id));
 			return id;
 		}
-
 		static Processor& get(ProcessorID);
-
 		static Processor& current() { return get(current_id()); }
 
+		static ProcessorID bsb_id() { return s_bsb_id; }
+		static bool current_is_bsb() { return current_id() == bsb_id(); }
+
 		static void set_interrupt_state(InterruptState state)
 		{
 			if (state == InterruptState::Enabled)
@@ -73,6 +74,8 @@ namespace Kernel
 		~Processor();
 
 	private:
+		static ProcessorID s_bsb_id;
+
 		void* m_stack { nullptr };
 		static constexpr size_t m_stack_size { 4096 };
 

kernel/kernel/Processor.cpp

@@ -4,10 +4,16 @@
 namespace Kernel
 {
 
+	ProcessorID Processor::s_bsb_id { PROCESSOR_NONE };
+
 	static BAN::Vector<Processor> s_processors;
 
 	Processor& Processor::create(ProcessorID id)
 	{
+		// bsb is the first processor
+		if (s_bsb_id == PROCESSOR_NONE)
+			s_bsb_id = id;
+
 		while (s_processors.size() <= id)
 			MUST(s_processors.emplace_back());
 		auto& processor = s_processors[id];