v4.19.13 snapshot.
diff --git a/arch/nios2/kernel/sys_nios2.c b/arch/nios2/kernel/sys_nios2.c
new file mode 100644
index 0000000..cd390ec
--- /dev/null
+++ b/arch/nios2/kernel/sys_nios2.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+
+#include <asm/cacheflush.h>
+#include <asm/traps.h>
+
+/* sys_cacheflush -- flush the processor cache. */
+asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len,
+ unsigned int op)
+{
+ struct vm_area_struct *vma;
+
+ if (len == 0)
+ return 0;
+
+ /* We only support op 0 now, return error if op is non-zero.*/
+ if (op)
+ return -EINVAL;
+
+ /* Check for overflow */
+ if (addr + len < addr)
+ return -EFAULT;
+
+ /*
+ * Verify that the specified address region actually belongs
+ * to this process.
+ */
+ vma = find_vma(current->mm, addr);
+ if (vma == NULL || addr < vma->vm_start || addr + len > vma->vm_end)
+ return -EFAULT;
+
+ flush_cache_range(vma, addr, addr + len);
+
+ return 0;
+}
+
+asmlinkage int sys_getpagesize(void)
+{
+ return PAGE_SIZE;
+}