hw: split pause_current_thread from pause_thread

Kernel::pause_current_thread can be implemented much simpler and is not
restricted to core threads, in contrast to Kernel::pause_thread which
also benefits from the split and can be moved to core_interface.h.

ref #1101

base-hw/include/kernel/interface.h

@@ -35,18 +35,18 @@ namespace Kernel
 	/**
 	 * Kernel names of the kernel calls
 	 */
-	constexpr Call_arg call_id_pause_thread()        { return 0; }
-	constexpr Call_arg call_id_resume_thread()       { return 1; }
-	constexpr Call_arg call_id_yield_thread()        { return 2; }
-	constexpr Call_arg call_id_send_request_msg()    { return 3; }
-	constexpr Call_arg call_id_send_reply_msg()      { return 4; }
-	constexpr Call_arg call_id_await_request_msg()   { return 5; }
-	constexpr Call_arg call_id_kill_signal_context() { return 6; }
-	constexpr Call_arg call_id_submit_signal()       { return 7; }
-	constexpr Call_arg call_id_await_signal()        { return 8; }
-	constexpr Call_arg call_id_signal_pending()      { return 9; }
-	constexpr Call_arg call_id_ack_signal()          { return 10; }
-	constexpr Call_arg call_id_print_char()          { return 11; }
+	constexpr Call_arg call_id_pause_current_thread() { return 0; }
+	constexpr Call_arg call_id_resume_thread()        { return 1; }
+	constexpr Call_arg call_id_yield_thread()         { return 2; }
+	constexpr Call_arg call_id_send_request_msg()     { return 3; }
+	constexpr Call_arg call_id_send_reply_msg()       { return 4; }
+	constexpr Call_arg call_id_await_request_msg()    { return 5; }
+	constexpr Call_arg call_id_kill_signal_context()  { return 6; }
+	constexpr Call_arg call_id_submit_signal()        { return 7; }
+	constexpr Call_arg call_id_await_signal()         { return 8; }
+	constexpr Call_arg call_id_signal_pending()       { return 9; }
+	constexpr Call_arg call_id_ack_signal()           { return 10; }
+	constexpr Call_arg call_id_print_char()           { return 11; }
 
 
 	/*****************************************************************
@@ -86,16 +86,11 @@ namespace Kernel
 
 
 	/**
-	 * Prevent thread from participating in CPU scheduling
-	 *
-	 * \param thread_id  kernel name of the targeted thread or 0
-	 *
-	 * If thread_id is set to 0 the caller targets itself. If the caller
-	 * doesn't target itself, the call is restricted to core threads.
+	 * Pause execution of calling thread
 	 */
-	inline void pause_thread(unsigned const thread_id)
+	inline void pause_current_thread()
 	{
-		call(call_id_pause_thread(), thread_id);
+		call(call_id_pause_current_thread());
 	}
 
 

base-hw/src/base/ipc.cc

@@ -55,7 +55,7 @@ Ipc_ostream::Ipc_ostream(Native_capability dst, Msgbuf_base *snd_msg)
 void Ipc_istream::_wait()
 {
 	/* FIXME: this shall be not supported */
-	Kernel::pause_thread(0);
+	Kernel::pause_current_thread();
 }
 
 

base-hw/src/base/lock/lock_helper.h

@@ -59,7 +59,7 @@ thread_check_stopped_and_restart(Genode::Thread_base * const t)
 /**
  * Pause execution of current thread
  */
-static inline void thread_stop_myself() { Kernel::pause_thread(0); }
+static inline void thread_stop_myself() { Kernel::pause_current_thread(); }
 
 
 #endif /* _LOCK_HELPER_H_ */

base-hw/src/core/include/platform.h

@@ -109,7 +109,7 @@ namespace Genode {
 
 			inline void wait_for_exit()
 			{
-				while (1) { Kernel::pause_thread(0); }
+				while (1) { Kernel::pause_current_thread(); }
 			};
 
 			bool supports_direct_unmap() const { return 1; }

base-hw/src/core/kernel/core_interface.h

@@ -47,6 +47,7 @@ namespace Kernel
 	constexpr Call_arg call_id_new_vm()              { return 25; }
 	constexpr Call_arg call_id_run_vm()              { return 26; }
 	constexpr Call_arg call_id_pause_vm()            { return 27; }
+	constexpr Call_arg call_id_pause_thread()        { return 28; }
 
 	/**
 	 * Create a domain
@@ -122,6 +123,17 @@ namespace Kernel
 	}
 
 
+	/**
+	 * Pause execution of a specific thread
+	 *
+	 * \param thread_id  kernel name of the targeted thread
+	 */
+	inline void pause_thread(unsigned const thread_id)
+	{
+		call(call_id_pause_thread(), thread_id);
+	}
+
+
 	/**
 	 * Destruct a thread
 	 *

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

@@ -380,25 +380,20 @@ void Thread::_call_start_thread()
 }
 
 
+void Thread::_call_pause_current_thread() { _pause(); }
+
+
 void Thread::_call_pause_thread()
 {
-	/* take a shortcut if a thread wants to pause itself */
-	unsigned const thread_id = user_arg_1();
-	if (!thread_id || thread_id == id()) {
-		_pause();
-		return;
-	}
 	/* check permissions */
 	if (!_core()) {
 		PWRN("not entitled to pause thread");
-		_stop();
 		return;
 	}
 	/* lookup thread */
-	Thread * const thread = Thread::pool()->object(thread_id);
+	Thread * const thread = Thread::pool()->object(user_arg_1());
 	if (!thread) {
 		PWRN("failed to lookup thread");
-		_stop();
 		return;
 	}
 	/* pause thread */
@@ -949,6 +944,7 @@ void Thread::_call(unsigned const processor_id)
 	case call_id_new_thread():           _call_new_thread(); return;
 	case call_id_bin_thread():           _call_bin_thread(); return;
 	case call_id_start_thread():         _call_start_thread(); return;
+	case call_id_pause_current_thread(): _call_pause_current_thread(); return;
 	case call_id_pause_thread():         _call_pause_thread(); return;
 	case call_id_resume_thread():        _call_resume_thread(); return;
 	case call_id_yield_thread():         _call_yield_thread(); return;

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

@@ -236,6 +236,7 @@ class Kernel::Thread
 		void _call_new_thread();
 		void _call_bin_thread();
 		void _call_start_thread();
+		void _call_pause_current_thread();
 		void _call_pause_thread();
 		void _call_resume_thread();
 		void _call_yield_thread();