Update xTaskGetIdleTaskHandle() For SMP (#868)

* Update xTaskGetIdleTaskHandle() in SMP

This commit updates xTaskGetIdleTaskHandle() for SMP in the following ways:

- xTaskGetIdleTaskHandle() no longer accepts xCoreID argument in SMP so that
there is not change in API between single-core and SMP
- xTaskGetIdleTaskHandle() now returns the Active idle task handle in SMP,
which matches the behavior in single-core.
- Added xTaskGetIdleTaskHandleForCore() in SMP which accepts an xCoreID
argument. This function can be used to obtain the Passive idle task handles.

* Update xTaskGetIdleTaskHandle

---------

Co-authored-by: Ching-Hsin Lee <chinglee@amazon.com>
Co-authored-by: chinglee-iot <61685396+chinglee-iot@users.noreply.github.com>
Co-authored-by: Rahul Kar <118818625+kar-rahul-aws@users.noreply.github.com>
Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>

include/FreeRTOS.h

@@ -1886,14 +1886,20 @@
     #ifndef traceENTER_xTaskGetIdleTaskHandle
         #define traceENTER_xTaskGetIdleTaskHandle()
     #endif
-#else
+#endif
-    #ifndef traceENTER_xTaskGetIdleTaskHandle
+
-        #define traceENTER_xTaskGetIdleTaskHandle( xCoreID )
+#if ( configNUMBER_OF_CORES == 1 )
+    #ifndef traceRETURN_xTaskGetIdleTaskHandle
+        #define traceRETURN_xTaskGetIdleTaskHandle( xIdleTaskHandle )
     #endif
 #endif
 
-#ifndef traceRETURN_xTaskGetIdleTaskHandle
+#ifndef traceENTER_xTaskGetIdleTaskHandleForCore
-    #define traceRETURN_xTaskGetIdleTaskHandle( xIdleTaskHandle )
+    #define traceENTER_xTaskGetIdleTaskHandleForCore( xCoreID )
+#endif
+
+#ifndef traceRETURN_xTaskGetIdleTaskHandleForCore
+    #define traceRETURN_xTaskGetIdleTaskHandleForCore( xIdleTaskHandle )
 #endif
 
 #ifndef traceENTER_vTaskStepTick

include/task.h

@@ -2030,24 +2030,23 @@ BaseType_t xTaskCallApplicationTaskHook( TaskHandle_t xTask,
  * xTaskGetIdleTaskHandle() is only available if
  * INCLUDE_xTaskGetIdleTaskHandle is set to 1 in FreeRTOSConfig.h.
  *
- * Simply returns the handle of the idle task.  It is not valid to call
+ * In single-core FreeRTOS, this function simply returns the handle of the idle
- * xTaskGetIdleTaskHandle() before the scheduler has been started.
+ * task. It is not valid to call xTaskGetIdleTaskHandle() before the scheduler
+ * has been started.
  *
  * In the FreeRTOS SMP, there are a total of configNUMBER_OF_CORES idle tasks:
  *  1. 1 Active idle task which does all the housekeeping.
  *  2. ( configNUMBER_OF_CORES - 1 ) Passive idle tasks which do nothing.
  * These idle tasks are created to ensure that each core has an idle task to run when
- * no other task is available to run.
+ * no other task is available to run. Call xTaskGetIdleTaskHandle() or
- *
+ * xTaskGetIdleTaskHandleForCore() with xCoreID set to 0  to get the Active
- * Set xCoreID to 0 to get the Active idle task handle. Set xCoreID to
+ * idle task handle. Call xTaskGetIdleTaskHandleForCore() with xCoreID set to
- * 1,2 ... ( configNUMBER_OF_CORES - 1 ) to get the Passive idle task
+ * 1,2 ... ( configNUMBER_OF_CORES - 1 ) to get the Passive idle task handles.
- * handles.
  */
 #if ( configNUMBER_OF_CORES == 1 )
     TaskHandle_t xTaskGetIdleTaskHandle( void ) PRIVILEGED_FUNCTION;
-#else /* #if ( configNUMBER_OF_CORES == 1 ) */
-    TaskHandle_t xTaskGetIdleTaskHandle( BaseType_t xCoreID ) PRIVILEGED_FUNCTION;
 #endif /* #if ( configNUMBER_OF_CORES == 1 ) */
+TaskHandle_t xTaskGetIdleTaskHandleForCore( BaseType_t xCoreID ) PRIVILEGED_FUNCTION;
 
 /**
  * configUSE_TRACE_FACILITY must be defined as 1 in FreeRTOSConfig.h for

tasks.c

@@ -4472,7 +4472,6 @@ char * pcTaskGetName( TaskHandle_t xTaskToQuery ) /*lint !e971 Unqualified char
 #if ( INCLUDE_xTaskGetIdleTaskHandle == 1 )
 
     #if ( configNUMBER_OF_CORES == 1 )
-
         TaskHandle_t xTaskGetIdleTaskHandle( void )
         {
             traceENTER_xTaskGetIdleTaskHandle();
@@ -4485,27 +4484,24 @@ char * pcTaskGetName( TaskHandle_t xTaskToQuery ) /*lint !e971 Unqualified char
 
             return xIdleTaskHandles[ 0 ];
         }
-
-    #else /* if ( configNUMBER_OF_CORES == 1 ) */
-
-        TaskHandle_t xTaskGetIdleTaskHandle( BaseType_t xCoreID )
-        {
-            traceENTER_xTaskGetIdleTaskHandle( xCoreID );
-
-            /* Ensure the core ID is valid. */
-            configASSERT( taskVALID_CORE_ID( xCoreID ) == pdTRUE );
-
-            /* If xTaskGetIdleTaskHandle() is called before the scheduler has been
-             * started, then xIdleTaskHandles will be NULL. */
-            configASSERT( ( xIdleTaskHandles[ xCoreID ] != NULL ) );
-
-            traceRETURN_xTaskGetIdleTaskHandle( xIdleTaskHandles[ xCoreID ] );
-
-            return xIdleTaskHandles[ xCoreID ];
-        }
-
     #endif /* if ( configNUMBER_OF_CORES == 1 ) */
 
+    TaskHandle_t xTaskGetIdleTaskHandleForCore( BaseType_t xCoreID )
+    {
+        traceENTER_xTaskGetIdleTaskHandleForCore( xCoreID );
+
+        /* Ensure the core ID is valid. */
+        configASSERT( taskVALID_CORE_ID( xCoreID ) == pdTRUE );
+
+        /* If xTaskGetIdleTaskHandle() is called before the scheduler has been
+         * started, then xIdleTaskHandles will be NULL. */
+        configASSERT( ( xIdleTaskHandles[ xCoreID ] != NULL ) );
+
+        traceRETURN_xTaskGetIdleTaskHandleForCore( xIdleTaskHandles[ xCoreID ] );
+
+        return xIdleTaskHandles[ xCoreID ];
+    }
+
 #endif /* INCLUDE_xTaskGetIdleTaskHandle */
 /*----------------------------------------------------------*/