Revision dc280d93623927570da279e99393879dbbab39e7 authored by Thomas Gleixner on 21 December 2016, 19:19:49 UTC, committed by Thomas Gleixner on 25 December 2016, 09:47:42 UTC
Developers manage to overwrite states blindly without thought. That's fatal and hard to debug. Add sanity checks to make it fail. This requries to restructure the code so that the dynamic state allocation happens in the same lock protected section as the actual store. Otherwise the previous assignment of 'Reserved' to the name field would trigger the overwrite check. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20161221192111.675234535@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
1 parent 59fefd0
tangox_wdt.c
/*
* Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
* SMP86xx/SMP87xx Watchdog driver
*
* 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/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#define DEFAULT_TIMEOUT 30
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout");
/*
* Counter counts down from programmed value. Reset asserts when
* the counter reaches 1.
*/
#define WD_COUNTER 0
#define WD_CONFIG 4
#define WD_CONFIG_XTAL_IN BIT(0)
#define WD_CONFIG_DISABLE BIT(31)
struct tangox_wdt_device {
struct watchdog_device wdt;
void __iomem *base;
unsigned long clk_rate;
struct clk *clk;
struct notifier_block restart;
};
static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
unsigned int new_timeout)
{
wdt->timeout = new_timeout;
return 0;
}
static int tangox_wdt_start(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
u32 ticks;
ticks = 1 + wdt->timeout * dev->clk_rate;
writel(ticks, dev->base + WD_COUNTER);
return 0;
}
static int tangox_wdt_stop(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
writel(0, dev->base + WD_COUNTER);
return 0;
}
static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt)
{
struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
u32 count;
count = readl(dev->base + WD_COUNTER);
if (!count)
return 0;
return (count - 1) / dev->clk_rate;
}
static const struct watchdog_info tangox_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "tangox watchdog",
};
static const struct watchdog_ops tangox_wdt_ops = {
.start = tangox_wdt_start,
.stop = tangox_wdt_stop,
.set_timeout = tangox_wdt_set_timeout,
.get_timeleft = tangox_wdt_get_timeleft,
};
static int tangox_wdt_restart(struct notifier_block *nb, unsigned long action,
void *data)
{
struct tangox_wdt_device *dev =
container_of(nb, struct tangox_wdt_device, restart);
writel(1, dev->base + WD_COUNTER);
return NOTIFY_DONE;
}
static int tangox_wdt_probe(struct platform_device *pdev)
{
struct tangox_wdt_device *dev;
struct resource *res;
u32 config;
int err;
dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(dev->base))
return PTR_ERR(dev->base);
dev->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dev->clk))
return PTR_ERR(dev->clk);
err = clk_prepare_enable(dev->clk);
if (err)
return err;
dev->clk_rate = clk_get_rate(dev->clk);
if (!dev->clk_rate) {
err = -EINVAL;
goto err;
}
dev->wdt.parent = &pdev->dev;
dev->wdt.info = &tangox_wdt_info;
dev->wdt.ops = &tangox_wdt_ops;
dev->wdt.timeout = DEFAULT_TIMEOUT;
dev->wdt.min_timeout = 1;
dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate;
watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
watchdog_set_nowayout(&dev->wdt, nowayout);
watchdog_set_drvdata(&dev->wdt, dev);
/*
* Deactivate counter if disable bit is set to avoid
* accidental reset.
*/
config = readl(dev->base + WD_CONFIG);
if (config & WD_CONFIG_DISABLE)
writel(0, dev->base + WD_COUNTER);
writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG);
/*
* Mark as active and restart with configured timeout if
* already running.
*/
if (readl(dev->base + WD_COUNTER)) {
set_bit(WDOG_HW_RUNNING, &dev->wdt.status);
tangox_wdt_start(&dev->wdt);
}
err = watchdog_register_device(&dev->wdt);
if (err)
goto err;
platform_set_drvdata(pdev, dev);
dev->restart.notifier_call = tangox_wdt_restart;
dev->restart.priority = 128;
err = register_restart_handler(&dev->restart);
if (err)
dev_warn(&pdev->dev, "failed to register restart handler\n");
dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n");
return 0;
err:
clk_disable_unprepare(dev->clk);
return err;
}
static int tangox_wdt_remove(struct platform_device *pdev)
{
struct tangox_wdt_device *dev = platform_get_drvdata(pdev);
tangox_wdt_stop(&dev->wdt);
clk_disable_unprepare(dev->clk);
unregister_restart_handler(&dev->restart);
watchdog_unregister_device(&dev->wdt);
return 0;
}
static const struct of_device_id tangox_wdt_dt_ids[] = {
{ .compatible = "sigma,smp8642-wdt" },
{ .compatible = "sigma,smp8759-wdt" },
{ }
};
MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids);
static struct platform_driver tangox_wdt_driver = {
.probe = tangox_wdt_probe,
.remove = tangox_wdt_remove,
.driver = {
.name = "tangox-wdt",
.of_match_table = tangox_wdt_dt_ids,
},
};
module_platform_driver(tangox_wdt_driver);
MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>");
MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
MODULE_LICENSE("GPL");
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