linux-kernel - Re: [PATCH] watchdog: bcm2835_wdt: set WDOG_HW

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 12 Dec 2016 06:44:51 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Rasmus Villemoes <rasmus.villemoes@...vas.dk>,
        Wim Van Sebroeck <wim@...ana.be>,
        Stephen Warren <swarren@...dotorg.org>,
        Lee Jones <lee@...nel.org>, Eric Anholt <eric@...olt.net>,
        Florian Fainelli <f.fainelli@...il.com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list@...adcom.com
Cc:     linux-watchdog@...r.kernel.org,
        linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] watchdog: bcm2835_wdt: set WDOG_HW_RUNNING bit when
 appropriate

On 12/12/2016 01:48 AM, Rasmus Villemoes wrote:
> A bootloader may start the watchdog device before handing control to
> the kernel - in that case, we should tell the kernel about it so the
> watchdog framework can keep it alive until userspace opens
> /dev/watchdog0.
>
> Signed-off-by: Rasmus Villemoes <rasmus.villemoes@...vas.dk>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/bcm2835_wdt.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c
> index 4dddd82..c32c45b 100644
> --- a/drivers/watchdog/bcm2835_wdt.c
> +++ b/drivers/watchdog/bcm2835_wdt.c
> @@ -55,6 +55,15 @@ struct bcm2835_wdt {
>  static unsigned int heartbeat;
>  static bool nowayout = WATCHDOG_NOWAYOUT;
>
> +static bool bcm2835_wdt_is_running(struct bcm2835_wdt *wdt)
> +{
> +	uint32_t cur;
> +
> +	cur = readl(wdt->base + PM_RSTC);
> +
> +	return !!(cur & PM_RSTC_WRCFG_FULL_RESET);
> +}
> +
>  static int bcm2835_wdt_start(struct watchdog_device *wdog)
>  {
>  	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
> @@ -181,6 +190,17 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
>  	watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
>  	watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
>  	bcm2835_wdt_wdd.parent = &pdev->dev;
> +	if (bcm2835_wdt_is_running(wdt)) {
> +		/*
> +		 * The currently active timeout value (set by the
> +		 * bootloader) may be different from the module
> +		 * heartbeat parameter or the value in device
> +		 * tree. But we just need to set WDOG_HW_RUNNING,
> +		 * because then the framework will "immediately" ping
> +		 * the device, updating the timeout.
> +		 */
> +		set_bit(WDOG_HW_RUNNING, &bcm2835_wdt_wdd.status);
> +	}
>  	err = watchdog_register_device(&bcm2835_wdt_wdd);
>  	if (err) {
>  		dev_err(dev, "Failed to register watchdog device");
>