diff --git a/libc/kernel/uapi/linux/memfd.h b/libc/kernel/uapi/linux/memfd.h
index e3e5cd5..914c076 100644
--- a/libc/kernel/uapi/linux/memfd.h
+++ b/libc/kernel/uapi/linux/memfd.h
@@ -30,7 +30,9 @@
 #define MFD_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB
 #define MFD_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB
 #define MFD_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB
+#define MFD_HUGE_32MB HUGETLB_FLAG_ENCODE_32MB
 #define MFD_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB
+#define MFD_HUGE_512MB HUGETLB_FLAG_ENCODE_512MB
 #define MFD_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB
 #define MFD_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB
 #define MFD_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB