Index: kernel/generic/include/atomic.h
===================================================================
--- kernel/generic/include/atomic.h	(revision 7a0359b903311f67678b4a0a3ebbcf0daf6eab38)
+++ kernel/generic/include/atomic.h	(revision ee1c2d9cd5399d6bcfa9ffa802a3e8598188074b)
@@ -53,4 +53,18 @@
 }
 
+
+/*
+ * If the architecture does not provide operations that are atomic
+ * only with respect to the local cpu (eg exception handlers) and
+ * not other cpus, implement these cpu local atomic operations with
+ * full blown smp-safe atomics.
+ */
+#ifndef local_atomic_exchange
+#define local_atomic_exchange(var_addr, new_val) \
+	__atomic_exchange_n((var_addr), (new_val), __ATOMIC_RELAXED)
+#endif
+
+
+
 #endif