v4.19.13 snapshot.
diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
new file mode 100644
index 0000000..21b9113
--- /dev/null
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPILINUX_KERNEL_PAGE_FLAGS_H
+#define _UAPILINUX_KERNEL_PAGE_FLAGS_H
+
+/*
+ * Stable page flag bits exported to user space
+ */
+
+#define KPF_LOCKED 0
+#define KPF_ERROR 1
+#define KPF_REFERENCED 2
+#define KPF_UPTODATE 3
+#define KPF_DIRTY 4
+#define KPF_LRU 5
+#define KPF_ACTIVE 6
+#define KPF_SLAB 7
+#define KPF_WRITEBACK 8
+#define KPF_RECLAIM 9
+#define KPF_BUDDY 10
+
+/* 11-20: new additions in 2.6.31 */
+#define KPF_MMAP 11
+#define KPF_ANON 12
+#define KPF_SWAPCACHE 13
+#define KPF_SWAPBACKED 14
+#define KPF_COMPOUND_HEAD 15
+#define KPF_COMPOUND_TAIL 16
+#define KPF_HUGE 17
+#define KPF_UNEVICTABLE 18
+#define KPF_HWPOISON 19
+#define KPF_NOPAGE 20
+
+#define KPF_KSM 21
+#define KPF_THP 22
+#define KPF_BALLOON 23
+#define KPF_ZERO_PAGE 24
+#define KPF_IDLE 25
+#define KPF_PGTABLE 26
+
+#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */