Add check for if the scheduler is running to MPU ports (#954)

* In the ARM_CM3_MPU and ARM_CM4_MPU Port function xPortIsAuthorizedToAccessBuffer() grant access to the buffer if xSchedulerRunning is false.

portable/GCC/ARM_CM3_MPU/port.c

@@ -1380,7 +1380,15 @@ BaseType_t xPortIsAuthorizedToAccessBuffer( const void * pvBuffer,
     BaseType_t xAccessGranted = pdFALSE;
     const xMPU_SETTINGS * xTaskMpuSettings = xTaskGetMPUSettings( NULL ); /* Calling task's MPU settings. */
 
-    if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
+    if( xSchedulerRunning == pdFALSE )
+    {
+        /* Grant access to all the kernel objects before the scheduler
+         * is started. It is necessary because there is no task running
+         * yet and therefore, we cannot use the permissions of any
+         * task. */
+        xAccessGranted = pdTRUE;
+    }
+    else if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
     {
         xAccessGranted = pdTRUE;
     }

portable/GCC/ARM_CM4_MPU/port.c

@@ -1523,7 +1523,15 @@ BaseType_t xPortIsAuthorizedToAccessBuffer( const void * pvBuffer,
     BaseType_t xAccessGranted = pdFALSE;
     const xMPU_SETTINGS * xTaskMpuSettings = xTaskGetMPUSettings( NULL ); /* Calling task's MPU settings. */
 
-    if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
+    if( xSchedulerRunning == pdFALSE )
+    {
+        /* Grant access to all the kernel objects before the scheduler
+         * is started. It is necessary because there is no task running
+         * yet and therefore, we cannot use the permissions of any
+         * task. */
+        xAccessGranted = pdTRUE;
+    }
+    else if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
     {
         xAccessGranted = pdTRUE;
     }

portable/IAR/ARM_CM4F_MPU/port.c

@@ -1253,7 +1253,15 @@ BaseType_t xPortIsAuthorizedToAccessBuffer( const void * pvBuffer,
     BaseType_t xAccessGranted = pdFALSE;
     const xMPU_SETTINGS * xTaskMpuSettings = xTaskGetMPUSettings( NULL ); /* Calling task's MPU settings. */
 
-    if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
+    if( xSchedulerRunning == pdFALSE )
+    {
+        /* Grant access to all the kernel objects before the scheduler
+         * is started. It is necessary because there is no task running
+         * yet and therefore, we cannot use the permissions of any
+         * task. */
+        xAccessGranted = pdTRUE;
+    }
+    else if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
     {
         xAccessGranted = pdTRUE;
     }

portable/RVDS/ARM_CM4_MPU/port.c

@@ -1508,7 +1508,16 @@ BaseType_t xPortIsAuthorizedToAccessBuffer( const void * pvBuffer,
     BaseType_t xAccessGranted = pdFALSE;
     const xMPU_SETTINGS * xTaskMpuSettings = xTaskGetMPUSettings( NULL ); /* Calling task's MPU settings. */
 
-    if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
+    
+    if( xSchedulerRunning == pdFALSE )
+    {
+        /* Grant access to all the kernel objects before the scheduler
+         * is started. It is necessary because there is no task running
+         * yet and therefore, we cannot use the permissions of any
+         * task. */
+        xAccessGranted = pdTRUE;
+    }
+    else if( ( xTaskMpuSettings->ulTaskFlags & portTASK_IS_PRIVILEGED_FLAG ) == portTASK_IS_PRIVILEGED_FLAG )
     {
         xAccessGranted = pdTRUE;
     }