score: Use priority inheritance for thread join

Threads may join the thread termination of another thread using the
pthread_join() or rtems_task_delete() directives.  The thread cancel operation
used a special case priority boosting mechanism implemented by
_Thread_Raise_real_priority().  The problem was that this approach

* is not transitive,

* does not account for priority adjustments of the calling task
  while waiting for the join,

* does not support clustered scheduling, and

* does not detect deadlocks.

All these problems are fixed by using a priority inheritance thread queue for
the join operation.

Close #4679.

2 files changed, 13 insertions, 36 deletions

diff --git a/cpukit/posix/src/cancel.c b/cpukit/posix/src/cancel.c
index 300055d68a..0fb2199f0a 100644
--- a/cpukit/posix/src/cancel.c
+++ b/cpukit/posix/src/cancel.c
@@ -75,7 +75,7 @@ int pthread_cancel( pthread_t thread )
   } else {
     _Thread_Dispatch_disable_with_CPU( cpu_self, &lock_context );
     _ISR_lock_ISR_enable( &lock_context );
-    _Thread_Cancel( the_thread, executing, PTHREAD_CANCELED );
+    (void) _Thread_Cancel( the_thread, executing, 0, PTHREAD_CANCELED );
     _Thread_Dispatch_enable( cpu_self );
   }
   return 0;
diff --git a/cpukit/posix/src/pthreadjoin.c b/cpukit/posix/src/pthreadjoin.c
index 84ff15ceec..e4f978f6b4 100644
--- a/cpukit/posix/src/pthreadjoin.c
+++ b/cpukit/posix/src/pthreadjoin.c
@@ -54,26 +54,16 @@ static int _POSIX_Threads_Join( pthread_t thread, void **value_ptr )
 {
   Thread_Control       *the_thread;
   Thread_queue_Context  queue_context;
-  Per_CPU_Control      *cpu_self;
   Thread_Control       *executing;
-  void                 *value;
+  Status_Control        status;
 
   _Thread_queue_Context_initialize( &queue_context );
-  _Thread_queue_Context_set_enqueue_do_nothing_extra( &queue_context );
   the_thread = _Thread_Get( thread, &queue_context.Lock_context.Lock_context );
 
   if ( the_thread == NULL ) {
     return ESRCH;
   }
 
-  cpu_self = _Per_CPU_Get();
-  executing = _Per_CPU_Get_executing( cpu_self );
-
-  if ( executing == the_thread ) {
-    _ISR_lock_ISR_enable( &queue_context.Lock_context.Lock_context );
-    return EDEADLK;
-  }
-
   _Thread_State_acquire_critical(
     the_thread,
     &queue_context.Lock_context.Lock_context
@@ -84,33 +74,20 @@ static int _POSIX_Threads_Join( pthread_t thread, void **value_ptr )
     return EINVAL;
   }
 
-  if ( _States_Is_waiting_for_join_at_exit( the_thread->current_state ) ) {
-    value = the_thread->Life.exit_value;
-    _Thread_Clear_state_locked( the_thread, STATES_WAITING_FOR_JOIN_AT_EXIT );
-    _Thread_Dispatch_disable_with_CPU(
-      cpu_self,
-      &queue_context.Lock_context.Lock_context
-    );
-    _Thread_State_release( the_thread, &queue_context.Lock_context.Lock_context );
-    _Thread_Dispatch_direct( cpu_self );
-  } else {
-    _Thread_Join(
-      the_thread,
-      STATES_INTERRUPTIBLE_BY_SIGNAL | STATES_WAITING_FOR_JOIN,
-      executing,
-      &queue_context
-    );
-
-    if ( _POSIX_Get_error_after_wait( executing ) != 0 ) {
-      _Assert( _POSIX_Get_error_after_wait( executing ) == EINTR );
-      return EINTR;
-    }
-
-    value = executing->Wait.return_argument;
+  executing = _Thread_Executing;
+  status = _Thread_Join(
+    the_thread,
+    STATES_INTERRUPTIBLE_BY_SIGNAL | STATES_WAITING_FOR_JOIN,
+    executing,
+    &queue_context
+  );
+
+  if ( status != STATUS_SUCCESSFUL ) {
+    return _POSIX_Get_error( status );
   }
 
   if ( value_ptr != NULL ) {
-    *value_ptr = value;
+    *value_ptr = executing->Wait.return_argument;
   }
 
   return 0;