1#include <linux/kernel.h>
2#include <linux/cpu.h>
3#include <linux/module.h>
4#include <linux/notifier.h>
5
6static int priority;
7static int cpu_up_prepare_error;
8static int cpu_down_prepare_error;
9
10module_param(priority, int, 0);
11MODULE_PARM_DESC(priority, "specify cpu notifier priority");
12
13module_param(cpu_up_prepare_error, int, 0644);
14MODULE_PARM_DESC(cpu_up_prepare_error,
15		"specify error code to inject CPU_UP_PREPARE action");
16
17module_param(cpu_down_prepare_error, int, 0644);
18MODULE_PARM_DESC(cpu_down_prepare_error,
19		"specify error code to inject CPU_DOWN_PREPARE action");
20
21static int err_inject_cpu_callback(struct notifier_block *nfb,
22				unsigned long action, void *hcpu)
23{
24	int err = 0;
25
26	switch (action) {
27	case CPU_UP_PREPARE:
28	case CPU_UP_PREPARE_FROZEN:
29		err = cpu_up_prepare_error;
30		break;
31	case CPU_DOWN_PREPARE:
32	case CPU_DOWN_PREPARE_FROZEN:
33		err = cpu_down_prepare_error;
34		break;
35	}
36	if (err)
37		printk(KERN_INFO "Injecting error (%d) at cpu notifier\n", err);
38
39	return notifier_from_errno(err);
40}
41
42static struct notifier_block err_inject_cpu_notifier = {
43	.notifier_call = err_inject_cpu_callback,
44};
45
46static int err_inject_init(void)
47{
48	err_inject_cpu_notifier.priority = priority;
49
50	return register_hotcpu_notifier(&err_inject_cpu_notifier);
51}
52
53static void err_inject_exit(void)
54{
55	unregister_hotcpu_notifier(&err_inject_cpu_notifier);
56}
57
58module_init(err_inject_init);
59module_exit(err_inject_exit);
60
61MODULE_DESCRIPTION("CPU notifier error injection module");
62MODULE_LICENSE("GPL");
63MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
64