linux/lib/cpu-notifier-error-inject.c
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   1#include <linux/kernel.h>
   2#include <linux/module.h>
   3#include <linux/cpu.h>
   4
   5#include "notifier-error-inject.h"
   6
   7static int priority;
   8module_param(priority, int, 0);
   9MODULE_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
  16static 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
  26static 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
  36static 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
  44static 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
  52static struct dentry *dir;
  53
  54static 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
  73static void err_inject_exit(void)
  74{
  75        cpuhp_remove_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE);
  76        debugfs_remove_recursive(dir);
  77}
  78
  79module_init(err_inject_init);
  80module_exit(err_inject_exit);
  81
  82MODULE_DESCRIPTION("CPU notifier error injection module");
  83MODULE_LICENSE("GPL");
  84MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
  85