bsp/realview-pbx-a9: Fix SMP startup

c/src/lib/libbsp/arm/realview-pbx-a9/startup/bspstarthooks.c

@@ -55,6 +55,20 @@ BSP_START_TEXT_SECTION static void setup_mmu_and_cache(void)
 
 BSP_START_TEXT_SECTION void bsp_start_hook_0(void)
 {
+#ifdef RTEMS_SMP
+  uint32_t cpu_id = arm_cortex_a9_get_multiprocessor_cpu_id();
+
+  /*
+   * QEMU jumps to the entry point of the ELF file on all processors.  Prevent
+   * a SMP_FATAL_MULTITASKING_START_ON_INVALID_PROCESSOR this way.
+   */
+  if ( cpu_id >= rtems_configuration_get_maximum_processors() ) {
+    while (true) {
+      _ARM_Wait_for_event();
+    }
+  }
+#endif
+
   arm_a9mpcore_start_hook_0();
 }