Add memory barrier instructions to Tasking CM4F port.

FreeRTOS/Source/portable/Tasking/ARM_CM4F/port.c

@@ -83,12 +83,10 @@
 /* Constants required to manipulate the NVIC. */
 #define portNVIC_SYSTICK_CTRL		( ( volatile unsigned long * ) 0xe000e010 )
 #define portNVIC_SYSTICK_LOAD		( ( volatile unsigned long * ) 0xe000e014 )
-#define portNVIC_INT_CTRL			( ( volatile unsigned long * ) 0xe000ed04 )
 #define portNVIC_SYSPRI2			( ( volatile unsigned long * ) 0xe000ed20 )
 #define portNVIC_SYSTICK_CLK		0x00000004
 #define portNVIC_SYSTICK_INT		0x00000002
 #define portNVIC_SYSTICK_ENABLE		0x00000001
-#define portNVIC_PENDSVSET			0x10000000
 #define portNVIC_PENDSV_PRI			( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 16 )
 #define portNVIC_SYSTICK_PRI		( ( ( unsigned long ) configKERNEL_INTERRUPT_PRIORITY ) << 24 )
 
@@ -204,10 +202,15 @@ void vPortEndScheduler( void )
 }
 /*-----------------------------------------------------------*/
 
-void vPortYieldFromISR( void )
+void vPortYield( void )
 {
 	/* Set a PendSV to request a context switch. */
 	*(portNVIC_INT_CTRL) = portNVIC_PENDSVSET;
+
+	/* Barriers are normally not required but do ensure the code is completely
+	within the specified behaviour for the architecture. */
+	__DSB();
+	__ISB();
 }
 /*-----------------------------------------------------------*/
 
@@ -215,6 +218,8 @@ void vPortEnterCritical( void )
 {
 	portDISABLE_INTERRUPTS();
 	ulCriticalNesting++;
+	__DSB();
+	__ISB();
 }
 /*-----------------------------------------------------------*/
 

FreeRTOS/Source/portable/Tasking/ARM_CM4F/portmacro.h

@@ -116,11 +116,12 @@ extern "C" {
 
 
 /* Scheduler utilities. */
-extern void vPortYieldFromISR( void );
+extern void vPortYield( void );
+#define portNVIC_INT_CTRL			( ( volatile unsigned long * ) 0xe000ed04 )
+#define portNVIC_PENDSVSET			0x10000000
+#define portYIELD()					vPortYield()
 
-#define portYIELD()					vPortYieldFromISR()
-
-#define portEND_SWITCHING_ISR( xSwitchRequired ) if( xSwitchRequired ) vPortYieldFromISR()
+#define portEND_SWITCHING_ISR( xSwitchRequired ) if( xSwitchRequired ) *(portNVIC_INT_CTRL) = portNVIC_PENDSVSET
 /*-----------------------------------------------------------*/