diff --git a/arch/nios2/lib/cache.c b/arch/nios2/lib/cache.c
index 8f543f2..d7fd9ca 100644
--- a/arch/nios2/lib/cache.c
+++ b/arch/nios2/lib/cache.c
@@ -8,6 +8,7 @@
 #include <cpu_func.h>
 #include <asm/cache.h>
 #include <asm/global_data.h>
+#include <linux/errno.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -127,3 +128,8 @@
 {
 	flush_dcache_all();
 }
+
+int __weak pgprot_set_attrs(phys_addr_t addr, size_t size, enum pgprot_attrs perm)
+{
+	return -ENOSYS;
+}