2 files changed, 24 insertions, 3 deletions
diff --git a/cpukit/score/include/rtems/score/isr.h b/cpukit/score/include/rtems/score/isr.h
index 320332dfd7..1359e91fd8 100644
--- a/cpukit/score/include/rtems/score/isr.h
+++ b/cpukit/score/include/rtems/score/isr.h
@@ -104,7 +104,10 @@ void _ISR_Handler_initialization ( void );
  *  the argument _level will contain the previous interrupt mask level.
  */
 #define _ISR_Disable( _level ) \
-        _CPU_ISR_Disable( _level )
+  do { \
+    _CPU_ISR_Disable( _level ); \
+    RTEMS_COMPILER_MEMORY_BARRIER(); \
+  } while (0)
 
 /**
  *  This routine enables interrupts to the previous interrupt mask
@@ -112,7 +115,10 @@ void _ISR_Handler_initialization ( void );
  *  enable interrupts so they can be processed again.
  */
 #define _ISR_Enable( _level ) \
-        _CPU_ISR_Enable( _level )
+  do { \
+    RTEMS_COMPILER_MEMORY_BARRIER(); \
+    _CPU_ISR_Enable( _level ); \
+  } while (0)
 
 /**
  *  This routine temporarily enables interrupts to the previous
@@ -127,7 +133,11 @@ void _ISR_Handler_initialization ( void );
  *  properly protects itself.
  */
 #define _ISR_Flash( _level ) \
-        _CPU_ISR_Flash( _level )
+  do { \
+    RTEMS_COMPILER_MEMORY_BARRIER(); \
+    _CPU_ISR_Flash( _level ); \
+    RTEMS_COMPILER_MEMORY_BARRIER(); \
+  } while (0)
 
 /**
  *  This routine installs new_handler as the interrupt service routine
diff --git a/cpukit/score/include/rtems/system.h b/cpukit/score/include/rtems/system.h
index 59d5b293af..9558155daf 100644
--- a/cpukit/score/include/rtems/system.h
+++ b/cpukit/score/include/rtems/system.h
@@ -135,6 +135,17 @@ extern "C" {
 # define RTEMS_INLINE_ROUTINE
 #endif
 
+/**
+ *  The following macro is a compiler specific way to ensure that memory
+ *  writes are not reordered around certian points.  This specifically can
+ *  impact interrupt disable and thread dispatching critical sections.
+ */
+#ifdef __GNUC__
+  #define RTEMS_COMPILER_MEMORY_BARRIER() asm volatile("" ::: "memory")
+#else
+  #define RTEMS_COMPILER_MEMORY_BARRIER()
+#endif
+
 #ifdef RTEMS_POSIX_API
 /** The following is used by the POSIX implementation to catch bad paths.  */
 int POSIX_MP_NOT_IMPLEMENTED( void );