[PATCH 4/6] score: _Scheduler_Is_non_preempt_mode_supported()

[Sebastian Huber]

If the non-preempt mode for threads is supported depends on the
scheduler implementation.  Add
_Scheduler_Is_non_preempt_mode_supported() to indicate this.

Update #3876.
---
 cpukit/include/rtems/scheduler.h           | 16 ++++++++++++++++
 cpukit/include/rtems/score/scheduler.h     |  8 ++++++++
 cpukit/include/rtems/score/schedulerimpl.h | 18 ++++++++++++++++++
 cpukit/rtems/src/taskmode.c                |  9 ++++++---
 cpukit/score/src/threadinitialize.c        |  5 ++++-
 5 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/cpukit/include/rtems/scheduler.h b/cpukit/include/rtems/scheduler.h
index dbc161a69d..955a83cfb4 100644
--- a/cpukit/include/rtems/scheduler.h
+++ b/cpukit/include/rtems/scheduler.h
@@ -26,6 +26,13 @@
 #define SCHEDULER_CONTEXT_NAME( name ) \
   _Configuration_Scheduler_ ## name
 
+#if defined(RTEMS_SMP)
+  #define SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( value ) \
+    , value
+#else
+  #define SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( value )
+#endif
+
 #if defined(RTEMS_SMP)
   /* This object doesn't exist and indicates a configuration error */
   extern const Scheduler_Control RTEMS_SCHEDULER_INVALID_INDEX;
@@ -72,6 +79,7 @@
       SCHEDULER_CBS_ENTRY_POINTS, \
       SCHEDULER_CBS_MAXIMUM_PRIORITY, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( true ) \
     }
 
   /* Provided for backward compatibility */
@@ -98,6 +106,7 @@
       SCHEDULER_EDF_ENTRY_POINTS, \
       SCHEDULER_EDF_MAXIMUM_PRIORITY, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( true ) \
     }
 
   /* Provided for backward compatibility */
@@ -131,6 +140,7 @@
       SCHEDULER_EDF_SMP_ENTRY_POINTS, \
       SCHEDULER_EDF_MAXIMUM_PRIORITY, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( false ) \
     }
 
   /* Provided for backward compatibility */
@@ -162,6 +172,7 @@
         SCHEDULER_PRIORITY_CONTEXT_NAME( name ).Ready \
       ) - 1, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( true ) \
     }
 
   /* Provided for backward compatibility */
@@ -193,6 +204,7 @@
         SCHEDULER_PRIORITY_AFFINITY_SMP_CONTEXT_NAME( name ).Ready \
       ) - 1, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( false ) \
     }
 
   /* Provided for backward compatibility */
@@ -224,6 +236,7 @@
         SCHEDULER_PRIORITY_SMP_CONTEXT_NAME( name ).Ready \
       ) - 1, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( false ) \
     }
 
   /* Provided for backward compatibility */
@@ -255,6 +268,7 @@
         SCHEDULER_STRONG_APA_CONTEXT_NAME( name ).Ready \
       ) - 1, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( false ) \
     }
 
   /* Provided for backward compatibility */
@@ -282,6 +296,7 @@
       SCHEDULER_SIMPLE_ENTRY_POINTS, \
       SCHEDULER_SIMPLE_MAXIMUM_PRIORITY, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( true ) \
     }
 
   /* Provided for backward compatibility */
@@ -309,6 +324,7 @@
       SCHEDULER_SIMPLE_SMP_ENTRY_POINTS, \
       SCHEDULER_SIMPLE_SMP_MAXIMUM_PRIORITY, \
       ( obj_name ) \
+      SCHEDULER_CONTROL_IS_NON_PREEMPT_MODE_SUPPORTED( false ) \
     }
 
   /* Provided for backward compatibility */
diff --git a/cpukit/include/rtems/score/scheduler.h b/cpukit/include/rtems/score/scheduler.h
index 15effd462c..9a6515ba1e 100644
--- a/cpukit/include/rtems/score/scheduler.h
+++ b/cpukit/include/rtems/score/scheduler.h
@@ -289,6 +289,14 @@ struct _Scheduler_Control {
    * @brief The scheduler name.
    */
   uint32_t name;
+
+#if defined(RTEMS_SMP)
+  /**
+   * @brief True if the non-preempt mode for threads is supported by the
+   * scheduler, otherwise false.
+   */
+  bool is_non_preempt_mode_supported;
+#endif
 };
 
 /**
diff --git a/cpukit/include/rtems/score/schedulerimpl.h b/cpukit/include/rtems/score/schedulerimpl.h
index dcc81fcbbf..e7fbb8b166 100644
--- a/cpukit/include/rtems/score/schedulerimpl.h
+++ b/cpukit/include/rtems/score/schedulerimpl.h
@@ -129,6 +129,24 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Release_critical(
 #endif
 }
 
+#if defined(RTEMS_SMP)
+/**
+ * @brief Indicate if the thread non-preempt mode is supported by the
+ * scheduler.
+ *
+ * @param scheduler The scheduler instance.
+ *
+ * @return True if the non-preempt mode for threads is supported by the
+ *   scheduler, otherwise false.
+ */
+RTEMS_INLINE_ROUTINE bool _Scheduler_Is_non_preempt_mode_supported(
+  const Scheduler_Control *scheduler
+)
+{
+  return scheduler->is_non_preempt_mode_supported;
+}
+#endif
+
 #if defined(RTEMS_SMP)
 void _Scheduler_Request_ask_for_help( Thread_Control *the_thread );
 
diff --git a/cpukit/rtems/src/taskmode.c b/cpukit/rtems/src/taskmode.c
index 8830f6bb5d..3ba5ce7f95 100644
--- a/cpukit/rtems/src/taskmode.c
+++ b/cpukit/rtems/src/taskmode.c
@@ -41,6 +41,8 @@ rtems_status_code rtems_task_mode(
   bool                needs_asr_dispatching;
   rtems_mode          old_mode;
 
+  executing = _Thread_Get_executing();
+
   if ( !previous_mode_set )
     return RTEMS_INVALID_ADDRESS;
 
@@ -48,7 +50,9 @@ rtems_status_code rtems_task_mode(
   if (
     ( mask & RTEMS_PREEMPT_MASK ) != 0
       && !_Modes_Is_preempt( mode_set )
-      && rtems_configuration_is_smp_enabled()
+      && !_Scheduler_Is_non_preempt_mode_supported(
+        _Thread_Scheduler_get_home( executing )
+      )
   ) {
     return RTEMS_NOT_IMPLEMENTED;
   }
@@ -71,8 +75,7 @@ rtems_status_code rtems_task_mode(
    * impact the executing thread. There should be no errors returned
    * past this point.
    */
- 
-  executing     = _Thread_Get_executing();
+
   api = executing->API_Extensions[ THREAD_API_RTEMS ];
   asr = &api->Signal;
 
diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 976c97701a..5145bcfdd8 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -63,7 +63,10 @@ bool _Thread_Initialize(
   the_thread->Start.allocated_stack = config->allocated_stack;
 
 #if defined(RTEMS_SMP)
-  if ( !config->is_preemptible && rtems_configuration_is_smp_enabled() ) {
+  if (
+    !config->is_preemptible
+      && !_Scheduler_Is_non_preempt_mode_supported( config->scheduler )
+  ) {
     goto failed;
   }
 #endif
-- 
2.16.4