diff --git a/libc/kernel/uapi/linux/fs.h b/libc/kernel/uapi/linux/fs.h
index c1e7726..9288653 100644
--- a/libc/kernel/uapi/linux/fs.h
+++ b/libc/kernel/uapi/linux/fs.h
@@ -184,4 +184,33 @@
 #define RWF_NOWAIT (( __kernel_rwf_t) 0x00000008)
 #define RWF_APPEND (( __kernel_rwf_t) 0x00000010)
 #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT | RWF_APPEND)
+#define PAGEMAP_SCAN _IOWR('f', 16, struct pm_scan_arg)
+#define PAGE_IS_WPALLOWED (1 << 0)
+#define PAGE_IS_WRITTEN (1 << 1)
+#define PAGE_IS_FILE (1 << 2)
+#define PAGE_IS_PRESENT (1 << 3)
+#define PAGE_IS_SWAPPED (1 << 4)
+#define PAGE_IS_PFNZERO (1 << 5)
+#define PAGE_IS_HUGE (1 << 6)
+struct page_region {
+  __u64 start;
+  __u64 end;
+  __u64 categories;
+};
+#define PM_SCAN_WP_MATCHING (1 << 0)
+#define PM_SCAN_CHECK_WPASYNC (1 << 1)
+struct pm_scan_arg {
+  __u64 size;
+  __u64 flags;
+  __u64 start;
+  __u64 end;
+  __u64 walk_end;
+  __u64 vec;
+  __u64 vec_len;
+  __u64 max_pages;
+  __u64 category_inverted;
+  __u64 category_mask;
+  __u64 category_anyof_mask;
+  __u64 return_mask;
+};
 #endif