lib/cpu-notifier-error-inject.c

   1 #include <linux/kernel.h>
   2 #include <linux/module.h>
   3 #include <linux/cpu.h>
   4
   5 #include "notifier-error-inject.h"
   6
   7 static int priority;
   8 module_param(priority, int, 0);
   9 MODULE_PARM_DESC(priority, "specify cpu notifier priority");
  10
  11 #define UP_PREPARE 0
  12 #define UP_PREPARE_FROZEN 0
  13 #define DOWN_PREPARE 0
  14 #define DOWN_PREPARE_FROZEN 0
  15
  16 static struct notifier_err_inject cpu_notifier_err_inject = {
  17         .actions = {
  18                 { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE) },
  19                 { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE_FROZEN) },
  20                 { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE) },
  21                 { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE_FROZEN) },
  22                 {}
  23         }
  24 };
  25
  26 static int notf_err_handle(struct notifier_err_inject_action *action)
  27 {
  28         int ret;
  29
  30         ret = action->error;
  31         if (ret)
  32                 pr_info("Injecting error (%d) to %s\n", ret, action->name);
  33         return ret;
  34 }
  35
  36 static int notf_err_inj_up_prepare(unsigned int cpu)
  37 {
  38         if (!cpuhp_tasks_frozen)
  39                 return notf_err_handle(&cpu_notifier_err_inject.actions[0]);
  40         else
  41                 return notf_err_handle(&cpu_notifier_err_inject.actions[1]);
  42 }
  43
  44 static int notf_err_inj_dead(unsigned int cpu)
  45 {
  46         if (!cpuhp_tasks_frozen)
  47                 return notf_err_handle(&cpu_notifier_err_inject.actions[2]);
  48         else
  49                 return notf_err_handle(&cpu_notifier_err_inject.actions[3]);
  50 }
  51
  52 static struct dentry *dir;
  53
  54 static int err_inject_init(void)
  55 {
  56         int err;
  57
  58         dir = notifier_err_inject_init("cpu", notifier_err_inject_dir,
  59                                         &cpu_notifier_err_inject, priority);
  60         if (IS_ERR(dir))
  61                 return PTR_ERR(dir);
  62
  63         err = cpuhp_setup_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE,
  64                                         "cpu-err-notif:prepare",
  65                                         notf_err_inj_up_prepare,
  66                                         notf_err_inj_dead);
  67         if (err)
  68                 debugfs_remove_recursive(dir);
  69
  70         return err;
  71 }
  72
  73 static void err_inject_exit(void)
  74 {
  75         cpuhp_remove_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE);
  76         debugfs_remove_recursive(dir);
  77 }
  78
  79 module_init(err_inject_init);
  80 module_exit(err_inject_exit);
  81
  82 MODULE_DESCRIPTION("CPU notifier error injection module");
  83 MODULE_LICENSE("GPL");
  84 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");