diff --git a/user/user.h b/user/user.h
index f16fe27828..ef62125814 100644
--- a/user/user.h
+++ b/user/user.h
@@ -41,3 +41,5 @@ void *memcpy(void *, const void *, uint);
 // umalloc.c
 void* malloc(uint);
 void free(void*);
+
+int getfreemem(void);