arm: Add _CPU_Thread_Idle_body for ARMv7-M

cpukit/score/cpu/arm/Makefile.am

@@ -33,6 +33,7 @@ libscorecpu_a_SOURCES += armv7m-isr-level-get.c
 libscorecpu_a_SOURCES += armv7m-isr-level-set.c
 libscorecpu_a_SOURCES += armv7m-isr-vector-install.c
 libscorecpu_a_SOURCES += armv7m-multitasking-start-stop.c
+libscorecpu_a_SOURCES += armv7m-thread-idle.c
 
 include $(srcdir)/preinstall.am
 include $(top_srcdir)/automake/local.am

cpukit/score/cpu/arm/armv7m-thread-idle.c

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/score/cpu.h>
+
+#ifdef ARM_MULTILIB_ARCH_V7M
+
+void *_CPU_Thread_Idle_body( uintptr_t ignored )
+{
+  while ( true ) {
+    __asm__ volatile ("wfi");
+  }
+}
+
+#endif /* ARM_MULTILIB_ARCH_V7M */

cpukit/score/cpu/arm/rtems/score/cpu.h

@@ -147,7 +147,11 @@
 
 #define CPU_USE_DEFERRED_FP_SWITCH FALSE
 
+#if defined(ARM_MULTILIB_ARCH_V7M)
+  #define CPU_PROVIDES_IDLE_THREAD_BODY TRUE
+#else
   #define CPU_PROVIDES_IDLE_THREAD_BODY FALSE
+#endif
 
 #define CPU_STACK_GROWS_UP FALSE
 
@@ -461,6 +465,10 @@ static inline uint16_t CPU_swap_u16( uint16_t value )
 #endif
 }
 
+#if CPU_PROVIDES_IDLE_THREAD_BODY == TRUE
+  void *_CPU_Thread_Idle_body( uintptr_t ignored );
+#endif
+
 /** @} */
 
 #if defined(ARM_MULTILIB_ARCH_V4)