hw: turn Native_utcb into restrictive class

fix #958

base-hw/include/base/native_types.h

@@ -57,17 +57,17 @@ namespace Genode
 	 * \param MAX_SIZE  maximum size the object is allowed to take
 	 */
 	template <size_t MAX_SIZE>
-	struct Message;
+	struct Message_tpl;
 
 	/**
-	 * Message that is communicated from a thread creator to the new thread
+	 * Information that a thread creator hands out to a new thread
 	 */
 	class Start_info;
 
 	/**
 	 * Memory region that is exclusive to every thread and known by the kernel
 	 */
-	struct Native_utcb;
+	class Native_utcb;
 
 	struct Cap_dst_policy
 	{
@@ -119,7 +119,7 @@ namespace Genode
 }
 
 template <Genode::size_t MAX_SIZE>
-class Genode::Message
+class Genode::Message_tpl
 {
 	private:
 
@@ -150,8 +150,9 @@ class Genode::Message
 		 * \return buf_size  size of receive buffer
 		 */
 		void info_about_await_request(void * & buf_base, size_t & buf_size)
+		const
 		{
-			buf_base = this;
+			buf_base = (void *)this;
 			buf_size = MAX_SIZE;
 		}
 
@@ -165,10 +166,11 @@ class Genode::Message
 		 */
 		void info_about_send_request(void * & msg_base, size_t & msg_size,
 		                             void * & buf_base, size_t & buf_size)
+		const
 		{
-			msg_base = this;
+			msg_base = (void *)this;
 			msg_size = _size();
-			buf_base = this;
+			buf_base = (void *)this;
 			buf_size = MAX_SIZE;
 		}
 
@@ -179,8 +181,9 @@ class Genode::Message
 		 * \return msg_size  size of complete send-message data
 		 */
 		void info_about_send_reply(void * & msg_base, size_t & msg_size)
+		const
 		{
-			msg_base = this;
+			msg_base = (void *)this;
 			msg_size = _size();
 		}
 
@@ -250,19 +253,28 @@ class Genode::Start_info
 		Native_thread_id thread_id() const { return _thread_id; }
 };
 
-struct Genode::Native_utcb
+class Genode::Native_utcb
 {
-	enum { SIZE = 1 << MIN_MAPPING_SIZE_LOG2 };
+	private:
 
-	union {
-		uint8_t       data[SIZE];
-		Message<SIZE> message;
-		Start_info    start_info;
-	};
+		uint8_t _data[1 << MIN_MAPPING_SIZE_LOG2];
 
-	size_t size() const { return SIZE; }
+	public:
 
-	void * base() const { return (void *)data; }
+		typedef Message_tpl<sizeof(_data)/sizeof(_data[0])> Message;
+
+
+		/***************
+		 ** Accessors **
+		 ***************/
+
+		Message * message() const { return (Message *)_data; }
+
+		Start_info * start_info() const { return (Start_info *)_data; }
+
+		size_t size() const { return sizeof(_data)/sizeof(_data[0]); }
+
+		void * base() const { return (void *)_data; }
 };
 
 #endif /* _BASE__NATIVE_TYPES_H_ */

base-hw/src/base/ipc.cc

@@ -79,12 +79,12 @@ void Ipc_client::_call()
 	/* send request and receive corresponding reply */
 	unsigned const local_name = Ipc_ostream::_dst.local_name();
 	Native_utcb * const utcb = Thread_base::myself()->utcb();
-	utcb->message.prepare_send(_snd_msg->buf, _write_offset, local_name);
+	utcb->message()->prepare_send(_snd_msg->buf, _write_offset, local_name);
 	if (Kernel::send_request_msg(Ipc_ostream::_dst.dst())) {
 		PERR("failed to receive reply");
 		throw Blocking_canceled();
 	}
-	utcb->message.finish_receive(_rcv_msg->buf, _rcv_msg->size());
+	utcb->message()->finish_receive(_rcv_msg->buf, _rcv_msg->size());
 
 	/* reset unmarshaller */
 	_write_offset = _read_offset = RPC_OBJECT_ID_SIZE;
@@ -129,7 +129,7 @@ void Ipc_server::_wait()
 		throw Blocking_canceled();
 	}
 	Native_utcb * const utcb = Thread_base::myself()->utcb();
-	utcb->message.finish_receive(_rcv_msg->buf, _rcv_msg->size());
+	utcb->message()->finish_receive(_rcv_msg->buf, _rcv_msg->size());
 
 	/* update server state */
 	_prepare_next_reply_wait();
@@ -140,7 +140,7 @@ void Ipc_server::_reply()
 {
 	unsigned const local_name = Ipc_ostream::_dst.local_name();
 	Native_utcb * const utcb = Thread_base::myself()->utcb();
-	utcb->message.prepare_send(_snd_msg->buf, _write_offset, local_name);
+	utcb->message()->prepare_send(_snd_msg->buf, _write_offset, local_name);
 	Kernel::send_reply_msg(0);
 }
 
@@ -155,12 +155,12 @@ void Ipc_server::_reply_wait()
 	/* send reply and receive next request */
 	unsigned const local_name = Ipc_ostream::_dst.local_name();
 	Native_utcb * const utcb = Thread_base::myself()->utcb();
-	utcb->message.prepare_send(_snd_msg->buf, _write_offset, local_name);
+	utcb->message()->prepare_send(_snd_msg->buf, _write_offset, local_name);
 	if (Kernel::send_reply_msg(1)) {
 		PERR("failed to receive request");
 		throw Blocking_canceled();
 	}
-	utcb->message.finish_receive(_rcv_msg->buf, _rcv_msg->size());
+	utcb->message()->finish_receive(_rcv_msg->buf, _rcv_msg->size());
 
 	/* update server state */
 	_prepare_next_reply_wait();

base-hw/src/base/thread/thread_bootstrap.cc

@@ -21,5 +21,5 @@
 void Genode::Thread_base::_thread_bootstrap()
 {
 	Native_utcb * const utcb = Thread_base::myself()->utcb();
-	_tid.thread_id = utcb->start_info.thread_id();
+	_tid.thread_id = utcb->start_info()->thread_id();
 }

base-hw/src/core/kernel/kernel.cc

@@ -234,7 +234,7 @@ extern "C" void kernel()
 			static Native_utcb utcb;
 			static Thread t(Priority::MAX, "core");
 			_main_thread_utcb = &utcb;
-			_main_thread_utcb->start_info.init(t.id());
+			_main_thread_utcb->start_info()->init(t.id());
 			t.ip = (addr_t)CORE_MAIN;;
 			t.sp = (addr_t)s + STACK_SIZE;
 			t.init(0, core_id(), &utcb, 1);

base-hw/src/core/kernel/thread.cc

@@ -452,7 +452,7 @@ void Thread::_call_await_request_msg()
 {
 	void * buf_base;
 	size_t buf_size;
-	_utcb_phys->message.info_about_await_request(buf_base, buf_size);
+	_utcb_phys->message()->info_about_await_request(buf_base, buf_size);
 	Ipc_node::await_request(buf_base, buf_size);
 }
 
@@ -469,8 +469,8 @@ void Thread::_call_send_request_msg()
 	size_t msg_size;
 	void * buf_base;
 	size_t buf_size;
-	_utcb_phys->message.info_about_send_request(msg_base, msg_size,
-	                                            buf_base, buf_size);
+	_utcb_phys->message()->info_about_send_request(msg_base, msg_size,
+	                                               buf_base, buf_size);
 	Ipc_node::send_request_await_reply(dst, msg_base, msg_size,
 	                                   buf_base, buf_size);
 }
@@ -480,7 +480,7 @@ void Thread::_call_send_reply_msg()
 {
 	void * msg_base;
 	size_t msg_size;
-	_utcb_phys->message.info_about_send_reply(msg_base, msg_size);
+	_utcb_phys->message()->info_about_send_reply(msg_base, msg_size);
 	Ipc_node::send_reply(msg_base, msg_size);
 	bool const await_request_msg = user_arg_1();
 	if (await_request_msg) { _call_await_request_msg(); }

base-hw/src/core/platform_thread.cc

@@ -201,7 +201,7 @@ int Platform_thread::start(void * const ip, void * const sp,
 		return -1;
 	}
 	/* start executing new thread */
-	_utcb_phys->start_info.init(_id);
+	_utcb_phys->start_info()->init(_id);
 	_tlb = Kernel::start_thread(_id, cpu_id, _pd_id, _utcb_phys);
 	if (!_tlb) {
 		PERR("failed to start thread");

base-hw/src/platform/main_bootstrap.cc

@@ -36,7 +36,7 @@ void Genode::platform_main_bootstrap()
 	static bool main_thread_id_valid = 0;
 	if (!main_thread_id_valid) {
 		Native_utcb * const utcb = Thread_base::myself()->utcb();
-		_main_thread_id = utcb->startup_info.thread_id();
+		_main_thread_id = utcb->start_info()->thread_id();
 		main_thread_id_valid = 1;
 	}
 }