1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Joe Lawrence <joe.lawrence@redhat.com>
3 
4 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5 
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/livepatch.h>
9 
10 static int replace;
11 module_param(replace, int, 0644);
12 MODULE_PARM_DESC(replace, "replace (default=0)");
13 
14 #include <linux/seq_file.h>
15 static int livepatch_meminfo_proc_show(struct seq_file *m, void *v)
16 {
17 	seq_printf(m, "%s: %s\n", THIS_MODULE->name,
18 		   "this has been live patched");
19 	return 0;
20 }
21 
22 static struct klp_func funcs[] = {
23 	{
24 		.old_name = "meminfo_proc_show",
25 		.new_func = livepatch_meminfo_proc_show,
26 	}, {}
27 };
28 
29 static struct klp_object objs[] = {
30 	{
31 		/* name being NULL means vmlinux */
32 		.funcs = funcs,
33 	}, {}
34 };
35 
36 static struct klp_patch patch = {
37 	.mod = THIS_MODULE,
38 	.objs = objs,
39 	/* set .replace in the init function below for demo purposes */
40 };
41 
42 static int test_klp_atomic_replace_init(void)
43 {
44 	patch.replace = replace;
45 	return klp_enable_patch(&patch);
46 }
47 
48 static void test_klp_atomic_replace_exit(void)
49 {
50 }
51 
52 module_init(test_klp_atomic_replace_init);
53 module_exit(test_klp_atomic_replace_exit);
54 MODULE_LICENSE("GPL");
55 MODULE_INFO(livepatch, "Y");
56 MODULE_AUTHOR("Joe Lawrence <joe.lawrence@redhat.com>");
57 MODULE_DESCRIPTION("Livepatch test: atomic replace");
58