1 files changed, 43 insertions, 0 deletions
diff --git a/lib/clz_ctz.c b/lib/clz_ctz.c
new file mode 100644
index 0000000000..fb8c0c5c2b
--- /dev/null
+++ b/lib/clz_ctz.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * lib/clz_ctz.c
+ *
+ * Copyright (C) 2013 Chanho Min <chanho.min@lge.com>
+ *
+ * The functions in this file aren't called directly, but are required by
+ * GCC builtins such as __builtin_ctz, and therefore they can't be removed
+ * despite appearing unreferenced in kernel source.
+ *
+ * __c[lt]z[sd]i2 can be overridden by linking arch-specific versions.
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+
+int __weak __ctzsi2(int val);
+int __weak __ctzsi2(int val)
+{
+	return __ffs(val);
+}
+EXPORT_SYMBOL(__ctzsi2);
+
+int __weak __clzsi2(int val);
+int __weak __clzsi2(int val)
+{
+	return 32 - fls(val);
+}
+EXPORT_SYMBOL(__clzsi2);
+
+int __weak __clzdi2(u64 val);
+int __weak __clzdi2(u64 val)
+{
+	return 64 - fls64(val);
+}
+EXPORT_SYMBOL(__clzdi2);
+
+int __weak __ctzdi2(u64 val);
+int __weak __ctzdi2(u64 val)
+{
+	return __ffs64(val);
+}
+EXPORT_SYMBOL(__ctzdi2);