Tofu: initial version

Change-Id: I9c464d5af883c18715a97ca9e9981cf73b260f90

kernel/include/mman.h

@@ -79,4 +79,14 @@
 
 extern int sysctl_overcommit_memory;
 
+/*
+ * This looks more complex than it should be. But we need to
+ * get the type for the ~ right in round_down (it needs to be
+ * as wide as the result!), and we want to evaluate the macro
+ * arguments just once each.
+ */
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+#define round_down(x, y) ((x) & ~__round_mask(x, y))
+
 #endif /* HEADER_MMAN_H */