From mboxrd@z Thu Jan  1 00:00:00 1970
From: Frans Klaver <frans.klaver-MHHw4NDrbWwAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 1/3] tty: omap-serial: prevent division by zero
Date: Tue, 29 Jul 2014 17:00:14 +0200
Message-ID: <20140729150014.GC32689@ci00147.xsens-tech.local>
References: <1406645577-18620-1-git-send-email-frans.klaver@xsens.com>
 <1406645577-18620-2-git-send-email-frans.klaver@xsens.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Return-path: <devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Content-Disposition: inline
In-Reply-To: <1406645577-18620-2-git-send-email-frans.klaver-MHHw4NDrbWwAvxtiuMwx3w@public.gmane.org>
Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
To: linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>, Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, Jiri Slaby <jslaby-AlSwsSmVLrQ@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
List-Id: devicetree@vger.kernel.org

Sorry, missed some CC's in git send-email.

On Tue, Jul 29, 2014 at 04:52:55PM +0200, Frans Klaver wrote:
> If the chosen baud rate is large enough (e.g. 3.5 megabaud), the
> calculated n13 and n16 values in serial_omap_baud_is_mode16 may become
> 0. This causes a division by zero when calculating the difference
> between calculated and desired baud rates. To prevent this, cap n13 and
> n16 on 1.
> 
> Signed-off-by: Frans Klaver <frans.klaver-MHHw4NDrbWwAvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/tty/serial/omap-serial.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> index d017cec..e454b7c 100644
> --- a/drivers/tty/serial/omap-serial.c
> +++ b/drivers/tty/serial/omap-serial.c
> @@ -254,8 +254,16 @@ serial_omap_baud_is_mode16(struct uart_port *port, unsigned int baud)
>  {
>  	unsigned int n13 = port->uartclk / (13 * baud);
>  	unsigned int n16 = port->uartclk / (16 * baud);
> -	int baudAbsDiff13 = baud - (port->uartclk / (13 * n13));
> -	int baudAbsDiff16 = baud - (port->uartclk / (16 * n16));
> +	int baudAbsDiff13;
> +	int baudAbsDiff16;
> +
> +	if (n13 == 0)
> +		n13 = 1;
> +	if (n16 == 0)
> +		n16 = 1;
> +
> +	baudAbsDiff13 = baud - (port->uartclk / (13 * n13));
> +	baudAbsDiff16 = baud - (port->uartclk / (16 * n16));
>  	if (baudAbsDiff13 < 0)
>  		baudAbsDiff13 = -baudAbsDiff13;
>  	if (baudAbsDiff16 < 0)
> -- 
> 1.9.3
> 
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html