Add SMP template port and example (#900)

* Add SMP template port and example
* Add readme file for smp configuration
* Update SMP build flow and add CI build

---------

Co-authored-by: Soren Ptak <ptaksoren@gmail.com>
Co-authored-by: Rahul Kar <118818625+kar-rahul-aws@users.noreply.github.com>

2 files changed, 99 insertions, 20 deletions

diff --git a/portable/template/port.c b/portable/template/port.c
index 4011eac15..d4eb56eac 100644
--- a/portable/template/port.c
+++ b/portable/template/port.c
@@ -25,8 +25,18 @@ StackType_t * pxPortInitialiseStack( StackType_t * pxTopOfStack,
 void vPortYield( void )
 {
     /* Save the current Context */
+
     /* Switch to the highest priority task that is ready to run. */
-    vTaskSwitchContext();
+    #if ( configNUMBER_OF_CORES == 1 )
+    {
+        vTaskSwitchContext();
+    }
+    #else
+    {
+        vTaskSwitchContext( portGET_CORE_ID() );
+    }
+    #endif
+
     /* Start executing the task we have just switched to. */
 }
 
@@ -35,12 +45,34 @@ static void prvTickISR( void )
     /* Interrupts must have been enabled for the ISR to fire, so we have to
      * save the context with interrupts enabled. */
 
-    /* Maintain the tick count. */
-    if( xTaskIncrementTick() != pdFALSE )
+    #if ( configNUMBER_OF_CORES == 1 )
     {
-        /* Switch to the highest priority task that is ready to run. */
-        vTaskSwitchContext();
+        /* Maintain the tick count. */
+        if( xTaskIncrementTick() != pdFALSE )
+        {
+            /* Switch to the highest priority task that is ready to run. */
+            vTaskSwitchContext();
+        }
+    }
+    #else
+    {
+        UBaseType_t ulPreviousMask;
+
+        /* Tasks or ISRs running on other cores may still in critical section in
+         * multiple cores environment. Incrementing tick needs to performed in
+         * critical section. */
+        ulPreviousMask = taskENTER_CRITICAL_FROM_ISR();
+
+        /* Maintain the tick count. */
+        if( xTaskIncrementTick() != pdFALSE )
+        {
+            /* Switch to the highest priority task that is ready to run. */
+            vTaskSwitchContext( portGET_CORE_ID() );
+        }
+
+        taskEXIT_CRITICAL_FROM_ISR( ulPreviousMask );
     }
+    #endif /* if ( configNUMBER_OF_CORES == 1 ) */
 
     /* start executing the new task */
 }
diff --git a/portable/template/portmacro.h b/portable/template/portmacro.h
index 4e4aa934d..199053208 100644
--- a/portable/template/portmacro.h
+++ b/portable/template/portmacro.h
@@ -64,26 +64,42 @@ typedef unsigned char    UBaseType_t;
 /*-----------------------------------------------------------*/
 
     #define portGET_HIGHEST_PRIORITY( uxTopPriority, uxReadyPriorities ) \
-    {                                                                    \
+    do {                                                                 \
         uxTopPriority = 0;                                               \
-    }                                                                    \
-    while( 0 )
+    } while( 0 )
 
 #endif /* configUSE_PORT_OPTIMISED_TASK_SELECTION */
 
-#define portDISABLE_INTERRUPTS()   \
-    { /* Disable the interrupts */ \
-    }
-#define portENABLE_INTERRUPTS()   \
-    { /* Enable the interrupts */ \
-    }
+/* Disable the interrupts */
+#define portDISABLE_INTERRUPTS()    do {} while( 0 )
 
-#define portENTER_CRITICAL()                                             \
-    { /* preserve current interrupt state and then disable interrupts */ \
-    }
-#define portEXIT_CRITICAL()                              \
-    { /* restore previously preserved interrupt state */ \
-    }
+/* Enable the interrupts */
+#define portENABLE_INTERRUPTS()     do {} while( 0 )
+
+#if ( configNUMBER_OF_CORES == 1 )
+/* preserve current interrupt state and then disable interrupts */
+    #define portENTER_CRITICAL()    do {} while( 0 )
+
+/* restore previously preserved interrupt state */
+    #define portEXIT_CRITICAL()     do {} while( 0 )
+#else
+
+/* The port can maintain the critical nesting count in TCB or maintain the critical
+ * nesting count in the port. */
+    #define portCRITICAL_NESTING_IN_TCB    1
+
+/* vTaskEnterCritical and vTaskExitCritical should be used in the implementation
+ * of portENTER/EXIT_CRITICAL if the number of cores is more than 1 in the system. */
+    #define portENTER_CRITICAL             vTaskEnterCritical
+    #define portEXIT_CRITICAL              vTaskExitCritical
+
+/* vTaskEnterCriticalFromISR and vTaskExitCriticalFromISR should be used in the
+ * implementation of portENTER/EXIT_CRITICAL_FROM_ISR if the number of cores is
+ * more than 1 in the system. */
+    #define portENTER_CRITICAL_FROM_ISR    vTaskEnterCriticalFromISR
+    #define portEXIT_CRITICAL_FROM_ISR     vTaskExitCriticalFromISR
+
+#endif /* if ( configNUMBER_OF_CORES == 1 ) */
 
 extern void vPortYield( void );
 #define portYIELD()                                           vPortYield()
@@ -92,4 +108,35 @@ extern void vPortYield( void );
 #define portTASK_FUNCTION_PROTO( vFunction, pvParameters )    void vFunction( void * pvParameters )
 #define portTASK_FUNCTION( vFunction, pvParameters )          void vFunction( void * pvParameters )
 
+#if ( configNUMBER_OF_CORES > 1 )
+    /* Return the core ID on which the code is running. */
+    #define portGET_CORE_ID()                0
+
+/* Set the interrupt mask. */
+    #define portSET_INTERRUPT_MASK()         0
+
+/* Clear the interrupt mask. */
+    #define portCLEAR_INTERRUPT_MASK( x )    ( ( void ) ( x ) )
+
+/* Request the core ID x to yield. */
+    #define portYIELD_CORE( x )              do {} while( 0 )
+
+/* Acquire the TASK lock. TASK lock is a recursive lock.
+ * It should be able to be locked by the same core multiple times. */
+    #define portGET_TASK_LOCK()              do {} while( 0 )
+
+/* Release the TASK lock. If a TASK lock is locked by the same core multiple times,
+ * it should be released as many times as it is locked. */
+    #define portRELEASE_TASK_LOCK()          do {} while( 0 )
+
+/* Acquire the ISR lock. ISR lock is a recursive lock.
+ * It should be able to be locked by the same core multiple times. */
+    #define portGET_ISR_LOCK()               do {} while( 0 )
+
+/* Release the ISR lock. If a ISR lock is locked by the same core multiple times, \
+ * it should be released as many times as it is locked. */
+    #define portRELEASE_ISR_LOCK()           do {} while( 0 )
+
+#endif /* if ( configNUMBER_OF_CORES > 1 ) */
+
 #endif /* PORTMACRO_H */