watchdog: pretimeout: add noop pretimeout governor

The change adds noop watchdog pretimeout governor, only an
informational message is printed to the kernel log buffer when a
watchdog triggers a pretimeout event.

While introducing the first pretimeout governor the selected design
assumes that the default pretimeout governor is selected by its name
and it is always built-in, thus the default pretimeout governor can
not be unregistered and the correspondent check can be removed from
the watchdog_unregister_governor() function.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This commit is contained in:
Vladimir Zapolskiy 2016-10-07 15:39:55 +03:00 committed by Wim Van Sebroeck
parent ff84136cb6
commit f77710c4cd
4 changed files with 81 additions and 0 deletions

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@ -1838,4 +1838,32 @@ config WATCHDOG_PRETIMEOUT_GOV
help
The option allows to select watchdog pretimeout governors.
if WATCHDOG_PRETIMEOUT_GOV
choice
prompt "Default Watchdog Pretimeout Governor"
default WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC
help
This option selects a default watchdog pretimeout governor.
The governor takes its action, if a watchdog is capable
to report a pretimeout event.
config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP
bool "noop"
select WATCHDOG_PRETIMEOUT_GOV_NOOP
help
Use noop watchdog pretimeout governor by default. If noop
governor is selected by a user, write a short message to
the kernel log buffer and don't do any system changes.
endchoice
config WATCHDOG_PRETIMEOUT_GOV_NOOP
tristate "Noop watchdog pretimeout governor"
help
Noop watchdog pretimeout governor, only an informational
message is added to kernel log buffer.
endif # WATCHDOG_PRETIMEOUT_GOV
endif # WATCHDOG

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@ -9,6 +9,8 @@ watchdog-objs += watchdog_core.o watchdog_dev.o
watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o
obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP) += pretimeout_noop.o
# Only one watchdog can succeed. We probe the ISA/PCI/USB based
# watchdog-cards first, then the architecture specific watchdog
# drivers and then the architecture independent "softdog" driver.

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@ -0,0 +1,47 @@
/*
* Copyright (C) 2015-2016 Mentor Graphics
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/watchdog.h>
#include "watchdog_pretimeout.h"
/**
* pretimeout_noop - No operation on watchdog pretimeout event
* @wdd - watchdog_device
*
* This function prints a message about pretimeout to kernel log.
*/
static void pretimeout_noop(struct watchdog_device *wdd)
{
pr_alert("watchdog%d: pretimeout event\n", wdd->id);
}
static struct watchdog_governor watchdog_gov_noop = {
.name = "noop",
.pretimeout = pretimeout_noop,
};
static int __init watchdog_gov_noop_register(void)
{
return watchdog_register_governor(&watchdog_gov_noop);
}
static void __exit watchdog_gov_noop_unregister(void)
{
watchdog_unregister_governor(&watchdog_gov_noop);
}
module_init(watchdog_gov_noop_register);
module_exit(watchdog_gov_noop_unregister);
MODULE_AUTHOR("Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>");
MODULE_DESCRIPTION("Panic watchdog pretimeout governor");
MODULE_LICENSE("GPL");

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@ -20,6 +20,10 @@ int watchdog_register_pretimeout(struct watchdog_device *wdd);
void watchdog_unregister_pretimeout(struct watchdog_device *wdd);
int watchdog_pretimeout_governor_get(struct watchdog_device *wdd, char *buf);
#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP)
#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "noop"
#endif
#else
static inline int watchdog_register_pretimeout(struct watchdog_device *wdd)
{