diff --git a/libc/kernel/common/linux/bitmap.h b/libc/kernel/common/linux/bitmap.h
new file mode 100644
index 0000000..246d158
--- /dev/null
+++ b/libc/kernel/common/linux/bitmap.h
@@ -0,0 +1,24 @@
+/****************************************************************************
+ ****************************************************************************
+ ***
+ ***   This header was automatically generated from a Linux kernel header
+ ***   of the same name, to make information necessary for userspace to
+ ***   call into the kernel available to libc.  It contains only constants,
+ ***   structures, and macros generated from the original header, and thus,
+ ***   contains no copyrightable information.
+ ***
+ ****************************************************************************
+ ****************************************************************************/
+#ifndef __LINUX_BITMAP_H
+#define __LINUX_BITMAP_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/string.h>
+
+#define BITMAP_LAST_WORD_MASK(nbits)  (   ((nbits) % BITS_PER_LONG) ?   (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL  )
+
+#endif
+#endif