linux/kernel/time/clocksource-wdtest.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Unit test for the clocksource watchdog.
 *
 * Copyright (C) 2021 Facebook, Inc.
 *
 * Author: Paul E. McKenney <[email protected]>
 */
#define pr_fmt(fmt) …

#include <linux/device.h>
#include <linux/clocksource.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/prandom.h>
#include <linux/cpu.h>

#include "tick-internal.h"

MODULE_LICENSE(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;

static int holdoff = …;
module_param(holdoff, int, 0444);
MODULE_PARM_DESC(…) …;

/* Watchdog kthread's task_struct pointer for debug purposes. */
static struct task_struct *wdtest_task;

static u64 wdtest_jiffies_read(struct clocksource *cs)
{ … }

static struct clocksource clocksource_wdtest_jiffies = …;

static int wdtest_ktime_read_ndelays;
static bool wdtest_ktime_read_fuzz;

static u64 wdtest_ktime_read(struct clocksource *cs)
{ … }

static void wdtest_ktime_cs_mark_unstable(struct clocksource *cs)
{ … }

#define KTIME_FLAGS …

static struct clocksource clocksource_wdtest_ktime = …;

/* Reset the clocksource if needed. */
static void wdtest_ktime_clocksource_reset(void)
{ … }

/* Run the specified series of watchdog tests. */
static int wdtest_func(void *arg)
{ … }

static void wdtest_print_module_parms(void)
{ … }

/* Cleanup function. */
static void clocksource_wdtest_cleanup(void)
{ … }

static int __init clocksource_wdtest_init(void)
{ … }

module_init(…) …;
module_exit(clocksource_wdtest_cleanup);