diff --git a/kernel/vm.c b/kernel/vm.c
index bccb405..0809aea 100644
--- a/kernel/vm.c
+++ b/kernel/vm.c
@@ -68,7 +68,7 @@ kvminithart()
 //   21..29 -- 9 bits of level-1 index.
 //   12..20 -- 9 bits of level-0 index.
 //    0..11 -- 12 bits of byte offset within the page.
-pte_t *
+static pte_t *
 walk(pagetable_t pagetable, uint64 va, int alloc)
 {
   if(va >= MAXVA)