v4.19.13 snapshot.
diff --git a/include/asm-generic/set_memory.h b/include/asm-generic/set_memory.h
new file mode 100644
index 0000000..c86abf6
--- /dev/null
+++ b/include/asm-generic/set_memory.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_SET_MEMORY_H
+#define __ASM_SET_MEMORY_H
+
+/*
+ * Functions to change memory attributes.
+ */
+int set_memory_ro(unsigned long addr, int numpages);
+int set_memory_rw(unsigned long addr, int numpages);
+int set_memory_x(unsigned long addr, int numpages);
+int set_memory_nx(unsigned long addr, int numpages);
+
+#endif