diff --git a/src/include/stdlib.h b/src/include/stdlib.h
index 83eb966b25..cb5a6ca703 100644
--- a/src/include/stdlib.h
+++ b/src/include/stdlib.h
@@ -7,6 +7,8 @@
 
 #define ALIGN(x,a)              __ALIGN_MASK(x,(typeof(x))(a)-1UL)
 #define __ALIGN_MASK(x,mask)    (((x)+(mask))&~(mask))
+#define ALIGN_UP(x,a)           ALIGN((x),(a))
+#define ALIGN_DOWN(x,a)         ((x) & ~((typeof(x))(a)-1UL))
 
 #define MIN(a,b) ((a) < (b) ? (a) : (b))
 #define MAX(a,b) ((a) > (b) ? (a) : (b))