Feature: SMP (#278)

* Add XMOS XCore ports

Some minor modifications are also made to the kernel to support the
XCore compiler's automatic stack size calculation.

* Update kernel to support SMP

The XMOS XCore ports are also updated to support SMP.

* Fix compiler warnings in xcore ports

The port set and clear interrupt mask from ISR macros were removed from
the ports so that the default macros found in FreeRTOS.h are used
instead. The default macros do not result in warnings when they are
used.

* Remove inline function from timers.h

Inline function converted to macro. This should now build when
optimizations are off and inlining is disabled.

* Fix compiler warnings in xcore ports and tasks.c

* fixed documentation for ulTaskNotifyTake() and ulTaskNotifyTakeIndexed()

* spelling fixes for tasks.c

Co-authored-by: Michael Bruno <mikeb@xmos.com>

include/task.h

@@ -214,6 +214,9 @@ typedef enum
  * task. h
  *
  * Macro to disable all maskable interrupts.
+ * This also returns what the interrupt state was
+ * upon being called. This state may subsequently
+ * be passed to taskRESTORE_INTERRUPTS().
  *
  * \defgroup taskDISABLE_INTERRUPTS taskDISABLE_INTERRUPTS
  * \ingroup SchedulerControl
@@ -230,6 +233,28 @@ typedef enum
  */
 #define taskENABLE_INTERRUPTS()            portENABLE_INTERRUPTS()
 
+/**
+ * task. h
+ *
+ * Macro to restore microcontroller interrupts to
+ * a previous state.
+ *
+ * \defgroup taskRESTORE_INTERRUPTS taskRESTORE_INTERRUPTS
+ * \ingroup SchedulerControl
+ */
+#define taskRESTORE_INTERRUPTS(ulState) portRESTORE_INTERRUPTS(ulState)
+
+/**
+ * task. h
+ *
+ * Macro that determines if it is being called from within an ISR
+ * or a task. Returns non-zero if it is in an ISR.
+ *
+ * \defgroup taskCHECK_IF_IN_ISR taskCHECK_IF_IN_ISR
+ * \ingroup SchedulerControl
+ */
+#define taskCHECK_IF_IN_ISR() portCHECK_IF_IN_ISR()
+
 /* Definitions returned by xTaskGetSchedulerState().  taskSCHEDULER_SUSPENDED is
  * 0 to generate more optimal code when configASSERT() is defined as the constant
  * is used in assert() statements. */
@@ -237,6 +262,8 @@ typedef enum
 #define taskSCHEDULER_NOT_STARTED    ( ( BaseType_t ) 1 )
 #define taskSCHEDULER_RUNNING        ( ( BaseType_t ) 2 )
 
+/* Check if core value is valid */
+#define taskVALID_CORE_ID( xCoreID ) ( ( BaseType_t ) ( ( 0 <= xCoreID ) && ( xCoreID < configNUM_CORES ) ) )
 
 /*-----------------------------------------------------------
 * TASK CREATION API
@@ -1208,6 +1235,12 @@ void vTaskResume( TaskHandle_t xTaskToResume ) PRIVILEGED_FUNCTION;
  */
 BaseType_t xTaskResumeFromISR( TaskHandle_t xTaskToResume ) PRIVILEGED_FUNCTION;
 
+void vTaskCoreExclusionSet( const TaskHandle_t xTask, UBaseType_t uxCoreExclude );
+UBaseType_t vTaskCoreExclusionGet( const TaskHandle_t xTask );
+
+void vTaskPreemptionDisable( const TaskHandle_t xTask );
+void vTaskPreemptionEnable( const TaskHandle_t xTask );
+
 /*-----------------------------------------------------------
 * SCHEDULER CONTROL
 *----------------------------------------------------------*/
@@ -1666,10 +1699,10 @@ 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
- * xTaskGetIdleTaskHandle() before the scheduler has been started.
+ * Simply returns a pointer to the array of idle task handles.
+ * It is not valid to call xTaskGetIdleTaskHandle() before the scheduler has been started.
  */
-TaskHandle_t xTaskGetIdleTaskHandle( void ) PRIVILEGED_FUNCTION;
+TaskHandle_t *xTaskGetIdleTaskHandle( void ) PRIVILEGED_FUNCTION;
 
 /**
  * configUSE_TRACE_FACILITY must be defined as 1 in FreeRTOSConfig.h for
@@ -2947,7 +2980,7 @@ void vTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem,
  * Sets the pointer to the current TCB to the TCB of the highest priority task
  * that is ready to run.
  */
-portDONT_DISCARD void vTaskSwitchContext( void ) PRIVILEGED_FUNCTION;
+portDONT_DISCARD void vTaskSwitchContext( BaseType_t xCoreID ) PRIVILEGED_FUNCTION;
 
 /*
  * THESE FUNCTIONS MUST NOT BE USED FROM APPLICATION CODE.  THEY ARE USED BY
@@ -2960,6 +2993,11 @@ TickType_t uxTaskResetEventItemValue( void ) PRIVILEGED_FUNCTION;
  */
 TaskHandle_t xTaskGetCurrentTaskHandle( void ) PRIVILEGED_FUNCTION;
 
+/*
+ * Return the handle of the task running on specified core.
+ */
+TaskHandle_t xTaskGetCurrentTaskHandleCPU( UBaseType_t xCoreID ) PRIVILEGED_FUNCTION;
+
 /*
  * Shortcut used by the queue implementation to prevent unnecessary call to
  * taskYIELD();
@@ -3045,6 +3083,11 @@ TaskHandle_t pvTaskIncrementMutexHeldCount( void ) PRIVILEGED_FUNCTION;
  */
 void vTaskInternalSetTimeOutState( TimeOut_t * const pxTimeOut ) PRIVILEGED_FUNCTION;
 
+/*
+ * For internal use only. Same as portYIELD_WITHIN_API() in single core FreeRTOS.
+ * For SMP this is not defined by the port.
+ */
+void vTaskYieldWithinAPI( void );
 
 /* *INDENT-OFF* */
 #ifdef __cplusplus