diff --git a/libc/kernel/uapi/linux/userfaultfd.h b/libc/kernel/uapi/linux/userfaultfd.h
index 09e0d80..816198f 100644
--- a/libc/kernel/uapi/linux/userfaultfd.h
+++ b/libc/kernel/uapi/linux/userfaultfd.h
@@ -23,7 +23,7 @@
 #define USERFAULTFD_IOC_NEW _IO(USERFAULTFD_IOC, 0x00)
 #define UFFD_API ((__u64) 0xAA)
 #define UFFD_API_REGISTER_MODES (UFFDIO_REGISTER_MODE_MISSING | UFFDIO_REGISTER_MODE_WP | UFFDIO_REGISTER_MODE_MINOR)
-#define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE | UFFD_FEATURE_EVENT_UNMAP | UFFD_FEATURE_MISSING_HUGETLBFS | UFFD_FEATURE_MISSING_SHMEM | UFFD_FEATURE_SIGBUS | UFFD_FEATURE_THREAD_ID | UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM | UFFD_FEATURE_EXACT_ADDRESS | UFFD_FEATURE_WP_HUGETLBFS_SHMEM)
+#define UFFD_API_FEATURES (UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_EVENT_FORK | UFFD_FEATURE_EVENT_REMAP | UFFD_FEATURE_EVENT_REMOVE | UFFD_FEATURE_EVENT_UNMAP | UFFD_FEATURE_MISSING_HUGETLBFS | UFFD_FEATURE_MISSING_SHMEM | UFFD_FEATURE_SIGBUS | UFFD_FEATURE_THREAD_ID | UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM | UFFD_FEATURE_EXACT_ADDRESS | UFFD_FEATURE_WP_HUGETLBFS_SHMEM | UFFD_FEATURE_WP_UNPOPULATED)
 #define UFFD_API_IOCTLS ((__u64) 1 << _UFFDIO_REGISTER | (__u64) 1 << _UFFDIO_UNREGISTER | (__u64) 1 << _UFFDIO_API)
 #define UFFD_API_RANGE_IOCTLS ((__u64) 1 << _UFFDIO_WAKE | (__u64) 1 << _UFFDIO_COPY | (__u64) 1 << _UFFDIO_ZEROPAGE | (__u64) 1 << _UFFDIO_WRITEPROTECT | (__u64) 1 << _UFFDIO_CONTINUE)
 #define UFFD_API_RANGE_IOCTLS_BASIC ((__u64) 1 << _UFFDIO_WAKE | (__u64) 1 << _UFFDIO_COPY | (__u64) 1 << _UFFDIO_CONTINUE | (__u64) 1 << _UFFDIO_WRITEPROTECT)
@@ -99,6 +99,7 @@
 #define UFFD_FEATURE_MINOR_SHMEM (1 << 10)
 #define UFFD_FEATURE_EXACT_ADDRESS (1 << 11)
 #define UFFD_FEATURE_WP_HUGETLBFS_SHMEM (1 << 12)
+#define UFFD_FEATURE_WP_UNPOPULATED (1 << 13)
   __u64 features;
   __u64 ioctls;
 };
@@ -138,6 +139,7 @@
 struct uffdio_continue {
   struct uffdio_range range;
 #define UFFDIO_CONTINUE_MODE_DONTWAKE ((__u64) 1 << 0)
+#define UFFDIO_CONTINUE_MODE_WP ((__u64) 1 << 1)
   __u64 mode;
   __s64 mapped;
 };