Add linker script memory filler for ARMv7-M MPU

The code snippet added here has been auto-generated by uVisor when
running the app in debug mode. The additional reserved space is needed
as a result of an ARMv7-M MPU limitation.

Author: AlessandroA

source/main.cpp

@@ -27,6 +27,12 @@ MAIN_ACL(g_main_acl);
 UVISOR_SET_MODE_ACL(UVISOR_ENABLED, g_main_acl);
 UVISOR_SET_PAGE_HEAP(2 * 1024, 8);
 
+/* Targets with an ARMv7-M MPU needs this space adjustment to prevent a runtime
+ * memory overflow error. The code below has been output directly by uVisor. */
+#if defined(TARGET_EFM32GG_STK3700) || defined(TARGET_DISCO_F429ZI)
+uint8_t __attribute__((section(".keep.uvisor.bss.boxes"), aligned(32))) __boxes_overhead[32640];
+#endif
+
 static void main_alloc(void)
 {
     const uint32_t kB = 1024;