score: PR2172: _Thread_queue_Extract()

Add _Thread_queue_Extract_with_return_code().  On SMP this sequence in
_Thread_queue_Process_timeout() was broken:

[...]
      /*
       * After we enable interrupts here, a lot may happen in the
       * meantime, e.g. nested interrupts may release the resource that
       * times out here.  So we enter _Thread_queue_Extract()
       * speculatively.  Inside this function we check the actual status
       * under ISR disable protection.  This ensures that exactly one
       * executing context performs the extract operation (other parties
       * may call _Thread_queue_Dequeue()).  If this context won, then
       * we have a timeout.
       *
       * We can use the_thread_queue pointer here even if
       * the_thread->Wait.queue is already set to NULL since the extract
       * operation will only use the thread queue discipline to select
       * the right extract operation.  The timeout status is set during
       * thread queue initialization.
       */
      we_did_it = _Thread_queue_Extract( the_thread_queue, the_thread );
      if ( we_did_it ) {
        the_thread->Wait.return_code = the_thread_queue->timeout_status;
      }
[...]

In case _Thread_queue_Extract() successfully extracted a thread, then
this thread may start execution on a remote processor immediately and
read the the_thread->Wait.return_code before we update it here with the
timeout status.  Thus it observes a successful operation even if it
timed out.

1 files changed, 14 insertions, 9 deletions

diff --git a/cpukit/score/include/rtems/score/threadqimpl.h b/cpukit/score/include/rtems/score/threadqimpl.h
index 040e16bc07..9d248121ac 100644
--- a/cpukit/score/include/rtems/score/threadqimpl.h
+++ b/cpukit/score/include/rtems/score/threadqimpl.h
@@ -135,15 +135,18 @@ void _Thread_queue_Requeue(
  *
  *  @param[in] the_thread_queue is the pointer to the ThreadQ header
  *  @param[in] the_thread is the pointer to a thread control block that is to be removed
- *
- *  @retval true The extract operation was performed by the executing context.
- *  @retval false Otherwise.
  */
-bool _Thread_queue_Extract(
+void _Thread_queue_Extract(
   Thread_queue_Control *the_thread_queue,
   Thread_Control       *the_thread
 );
 
+void _Thread_queue_Extract_with_return_code(
+  Thread_queue_Control *the_thread_queue,
+  Thread_Control       *the_thread,
+  uint32_t              return_code
+);
+
 /**
  *  @brief Extracts the_thread from the_thread_queue.
  *
@@ -265,8 +268,9 @@ Thread_blocking_operation_States _Thread_queue_Enqueue_priority (
  *  @retval true The extract operation was performed by the executing context.
  *  @retval false Otherwise.
  */
-bool _Thread_queue_Extract_priority_helper(
+void _Thread_queue_Extract_priority_helper(
   Thread_Control       *the_thread,
+  uint32_t              return_code,
   bool                  requeuing
 );
 
@@ -276,8 +280,8 @@ bool _Thread_queue_Extract_priority_helper(
  * This macro wraps the underlying call and hides the requeuing argument.
  */
 
-#define _Thread_queue_Extract_priority( _the_thread ) \
-  _Thread_queue_Extract_priority_helper( _the_thread, false )
+#define _Thread_queue_Extract_priority( _the_thread, _return_code ) \
+  _Thread_queue_Extract_priority_helper( _the_thread, _return_code, false )
 /**
  *  @brief Get highest priority thread on the_thread_queue.
  *
@@ -337,8 +341,9 @@ Thread_blocking_operation_States _Thread_queue_Enqueue_fifo (
  *  This routine removes the_thread from the_thread_queue
  *  and cancels any timeouts associated with this blocking.
  */
-bool _Thread_queue_Extract_fifo(
-  Thread_Control       *the_thread
+void _Thread_queue_Extract_fifo(
+  Thread_Control       *the_thread,
+  uint32_t              return_code
 );
 
 /**