score: Add API extensions post switch list

Move post switch hook from API_extensions_Control to new
API_extensions_Post_switch_control.  Rename
_API_extensions_Run_postswitch() in _API_extensions_Run_post_switch().
Add _API_extensions_Post_switch_list and
_API_extensions_Add_post_switch().

1 files changed, 44 insertions, 15 deletions

diff --git a/cpukit/score/include/rtems/score/apiext.h b/cpukit/score/include/rtems/score/apiext.h
index 82910bfc0d..db77a8b9c8 100644
--- a/cpukit/score/include/rtems/score/apiext.h
+++ b/cpukit/score/include/rtems/score/apiext.h
@@ -46,9 +46,9 @@
 typedef void (*API_extensions_Postdriver_hook)(void);
 
 /**
- *  This type defines the prototype of the Postswitch Hook.
+ *  This type defines the prototype of the Post Switch Hook.
  */
-typedef void (*API_extensions_Postswitch_hook)(
+typedef void (*API_extensions_Post_switch_hook)(
                  Thread_Control *
              );
 
@@ -77,20 +77,34 @@ typedef struct {
    * @note If this field is NULL, no extension is invoked.
    */
   API_extensions_Postdriver_hook  postdriver_hook;
+}  API_extensions_Control;
+
+/**
+ * @brief Control structure for post switch hooks.
+ */
+typedef struct {
+  Chain_Node Node;
+
   /**
-   * This field is the callout invoked during each context switch
-   * in the context of the heir thread.
+   * @brief The hook invoked during each context switch in the context of the
+   * heir thread.
    *
-   * @note If this field is NULL, no extension is invoked.
+   * This hook must not be NULL.
    */
-  API_extensions_Postswitch_hook  postswitch_hook;
-}  API_extensions_Control;
+  API_extensions_Post_switch_hook hook;
+} API_extensions_Post_switch_control;
 
 /**
  *  This is the list of API extensions to the system initialization.
  */
 SCORE_EXTERN Chain_Control _API_extensions_List;
 
+
+/**
+ * @brief The API extensions post switch list.
+ */
+SCORE_EXTERN Chain_Control _API_extensions_Post_switch_list;
+
 /**
  *  @brief Initialize the API Extensions Handler
  *
@@ -109,6 +123,23 @@ void _API_extensions_Add(
   API_extensions_Control *the_extension
 );
 
+/**
+ * @brief Adds the API extension post switch control to the post switch list.
+ *
+ * The post switch control is only added to the list if it is in the off chain
+ * state.  Thus this function can be called multiple times with the same
+ * post switch control and only the first invocation will actually add it to the
+ * list.
+ *
+ * There is no protection against concurrent access.  This function must be
+ * called within a _Thread_Disable_dispatch() critical section.
+ *
+ * @param [in, out] post_switch The post switch control.
+ */
+void _API_extensions_Add_post_switch(
+  API_extensions_Post_switch_control *post_switch
+);
+
 #if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
 /**
  *  @brief Execute all Pre-Driver Extensions
@@ -126,21 +157,19 @@ void _API_extensions_Add(
 void _API_extensions_Run_postdriver( void );
 
 /**
- *  @brief Execute all Post Context Switch Extensions
- *
- *  This routine executes all of the post context switch callouts.
+ * @brief Runs all API extension post switch hooks.
  */
-static inline void _API_extensions_Run_postswitch( Thread_Control *executing )
+static inline void _API_extensions_Run_post_switch( Thread_Control *executing )
 {
-  const Chain_Control *chain = &_API_extensions_List;
+  const Chain_Control *chain = &_API_extensions_Post_switch_list;
   const Chain_Node    *tail = _Chain_Immutable_tail( chain );
   const Chain_Node    *node = _Chain_Immutable_first( chain );
 
   while ( node != tail ) {
-    const API_extensions_Control *extension =
-      (const API_extensions_Control *) node;
+    const API_extensions_Post_switch_control *post_switch =
+      (const API_extensions_Post_switch_control *) node;
 
-    (*extension->postswitch_hook)( executing );
+    (*post_switch->hook)( executing );
 
     node = _Chain_Immutable_next( node );
   }