score: Add SMP scheduler make/clean sticky

This patch fixes the following broken behaviour:

  While a thread is scheduled on a helping scheduler, while it does not
  own a MrsP semaphore, if it obtains a MrsP semaphore, then no
  scheduler node using an idle thread and the ceiling priority of the
  semaphore is unblocked for the home scheduler.

This could lead to priority inversion issues and is not in line
with the MrsP protocol.

Introduce two new scheduler operations which are only enabled if
RTEMS_SMP is defined.  The operations are used to make the scheduler
node of the home scheduler sticky and to clean the sticky property.
This helps to keep the sticky handing out of the frequently used
priority update operation.

Close #4532.

1 files changed, 32 insertions, 0 deletions

diff --git a/cpukit/include/rtems/score/schedulerprioritysmp.h b/cpukit/include/rtems/score/schedulerprioritysmp.h
index fe314fb05b..9ece9ae143 100644
--- a/cpukit/include/rtems/score/schedulerprioritysmp.h
+++ b/cpukit/include/rtems/score/schedulerprioritysmp.h
@@ -93,6 +93,8 @@ typedef struct {
     _Scheduler_priority_SMP_Ask_for_help, \
     _Scheduler_priority_SMP_Reconsider_help_request, \
     _Scheduler_priority_SMP_Withdraw_node, \
+    _Scheduler_priority_SMP_Make_sticky, \
+    _Scheduler_priority_SMP_Clean_sticky, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_priority_SMP_Add_processor, \
@@ -215,6 +217,36 @@ void _Scheduler_priority_SMP_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_priority_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_priority_SMP_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Adds @a idle to @a scheduler.
  *
  * @param[in, out] scheduler The scheduler instance to add the processor to.