[PATCH 14/15] static_call: Simple self-test module

[Peter Zijlstra <peterz@infradead.org>]

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 lib/Kconfig.debug      |    8 ++++++++
 lib/Makefile           |    1 +
 lib/test_static_call.c |   41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+)

--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1955,6 +1955,14 @@ config TEST_STATIC_KEYS
 
 	  If unsure, say N.
 
+config TEST_STATIC_CALL
+	tristate "Test static call"
+	depends on m
+	help
+	  Test the static call interfaces.
+
+	  If unsure, say N.
+
 config TEST_KMOD
 	tristate "kmod stress tester"
 	depends on m
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -79,6 +79,7 @@ obj-$(CONFIG_TEST_SORT) += test_sort.o
 obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
+obj-$(CONFIG_TEST_STATIC_CALL) += test_static_call.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
 obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o
--- /dev/null
+++ b/lib/test_static_call.c
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/module.h>
+#include <linux/static_call.h>
+#include <asm/bug.h>
+
+static int foo_a(int x)
+{
+	return x+1;
+}
+
+static int foo_b(int x)
+{
+	return x*2;
+}
+
+DEFINE_STATIC_CALL(foo, foo_a);
+
+static int __init test_static_call_init(void)
+{
+	WARN_ON(static_call(foo, 2) != 3);
+
+	static_call_update(foo, foo_b);
+
+	WARN_ON(static_call(foo, 2) != 4);
+
+	static_call_update(foo, foo_a);
+
+	WARN_ON(static_call(foo, 2) != 3);
+
+	return 0;
+}
+module_init(test_static_call_init);
+
+static void __exit test_static_call_exit(void)
+{
+}
+module_exit(test_static_call_exit);
+
+MODULE_AUTHOR("Peter Zijlstra <peterz@infradead.org>");
+MODULE_LICENSE("GPL");