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Subject: Re: [PATCH] watchdog: iTCO_wdt: Fix detection of SMI-off case
To:     Jan Kiszka <jan.kiszka@siemens.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>
Cc:     linux-watchdog@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Christian Storm <christian.storm@siemens.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        =?UTF-8?Q?Mantas_Mikul=c4=97nas?= <grawity@gmail.com>,
        stable <stable@vger.kernel.org>
References: <d84f8e06-f646-8b43-d063-fb11f4827044@siemens.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <b3b75b72-33d4-ce21-a8f4-77a37156aa9e@redhat.com>
Date:   Mon, 26 Jul 2021 14:03:25 +0200
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On 26/07/21 13:46, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> Obviously, the test needs to run against the register content, not its
> address.
> 
> Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout")
> Reported-by: Mantas Mikulėnas <grawity@gmail.com>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>   drivers/watchdog/iTCO_wdt.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index b3f604669e2c..643c6c2d0b72 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -362,7 +362,7 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t)
>   	 * Otherwise, the BIOS generally reboots when the SMI triggers.
>   	 */
>   	if (p->smi_res &&
> -	    (SMI_EN(p) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
> +	    (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
>   		tmrval /= 2;
>   
>   	/* from the specs: */
> 

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org

(the latter because cb011044e34c has been picked up by stable kernels 
already).

Paolo