diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 4b29e50..f770039 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -396,6 +396,12 @@
 #define cpu_present(cpu)	((cpu) == 0)
 #endif
 
+#ifdef CONFIG_SMP
+int highest_possible_processor_id(void);
+#else
+#define highest_possible_processor_id()	0
+#endif
+
 #define any_online_cpu(mask)			\
 ({						\
 	int cpu;				\
@@ -409,14 +415,5 @@
 #define for_each_online_cpu(cpu)  for_each_cpu_mask((cpu), cpu_online_map)
 #define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map)
 
-/* Find the highest possible smp_processor_id() */
-#define highest_possible_processor_id() \
-({ \
-	unsigned int cpu, highest = 0; \
-	for_each_cpu_mask(cpu, cpu_possible_map) \
-		highest = cpu; \
-	highest; \
-})
-
 
 #endif /* __LINUX_CPUMASK_H */
diff --git a/lib/cpumask.c b/lib/cpumask.c
index ba2f854..ea25a03 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -14,3 +14,20 @@
 	return min_t(int, NR_CPUS, find_next_bit(srcp->bits, NR_CPUS, n+1));
 }
 EXPORT_SYMBOL(__next_cpu);
+
+/*
+ * Find the highest possible smp_processor_id()
+ *
+ * Note: if we're prepared to assume that cpu_possible_map never changes
+ * (reasonable) then this function should cache its return value.
+ */
+int highest_possible_processor_id(void)
+{
+	unsigned int cpu;
+	unsigned highest = 0;
+
+	for_each_cpu_mask(cpu, cpu_possible_map)
+		highest = cpu;
+	return highest;
+}
+EXPORT_SYMBOL(highest_possible_processor_id);