From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bh-25.webhostbox.net ([208.91.199.152]:45756 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750991AbcLMV5k (ORCPT ); Tue, 13 Dec 2016 16:57:40 -0500 Date: Tue, 13 Dec 2016 13:56:41 -0800 From: Guenter Roeck To: Jean Delvare Cc: Hardware Monitoring Subject: Re: [PATCH 16/17] hwmon: (gl518sm) Fix overflows seen when writing into limit attributes Message-ID: <20161213215641.GA13206@roeck-us.net> References: <1480913740-5678-1-git-send-email-linux@roeck-us.net> <1480913740-5678-16-git-send-email-linux@roeck-us.net> <20161213104829.47be4e91@endymion> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161213104829.47be4e91@endymion> Sender: linux-hwmon-owner@vger.kernel.org List-Id: linux-hwmon@vger.kernel.org Hi Jean, On Tue, Dec 13, 2016 at 10:48:29AM +0100, Jean Delvare wrote: > Hi Guenter, > > On Sun, 4 Dec 2016 20:55:39 -0800, Guenter Roeck wrote: > > Writes into limit attributes can overflow due to additions and > > multiplications with unchecked parameters. > > > > Signed-off-by: Guenter Roeck > > --- > > drivers/hwmon/gl518sm.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/hwmon/gl518sm.c b/drivers/hwmon/gl518sm.c > > index 0212c8317bca..0a11a550c2a2 100644 > > --- a/drivers/hwmon/gl518sm.c > > +++ b/drivers/hwmon/gl518sm.c > > @@ -86,9 +86,8 @@ enum chips { gl518sm_r00, gl518sm_r80 }; > > #define BOOL_FROM_REG(val) ((val) ? 0 : 1) > > #define BOOL_TO_REG(val) ((val) ? 0 : 1) > > > > -#define TEMP_TO_REG(val) clamp_val(((((val) < 0 ? \ > > - (val) - 500 : \ > > - (val) + 500) / 1000) + 119), 0, 255) > > +#define TEMP_TO_REG(val) (DIV_ROUND_CLOSEST(clamp_val(val, -119000, 136000), \ > > + 1000) + 119) > > #define TEMP_FROM_REG(val) (((val) - 119) * 1000) > > > > static inline u8 FAN_TO_REG(long rpm, int div) > > @@ -101,10 +100,11 @@ static inline u8 FAN_TO_REG(long rpm, int div) > > } > > #define FAN_FROM_REG(val, div) ((val) == 0 ? 0 : (480000 / ((val) * (div)))) > > > > -#define IN_TO_REG(val) clamp_val((((val) + 9) / 19), 0, 255) > > +#define IN_TO_REG(val) DIV_ROUND_CLOSEST(clamp_val(val, 0, 255 * 19), 19) > > #define IN_FROM_REG(val) ((val) * 19) > > > > -#define VDD_TO_REG(val) clamp_val((((val) * 4 + 47) / 95), 0, 255) > > +#define VDD_TO_REG(val) \ > > + DIV_ROUND_CLOSEST(clamp_val(val, 0, 255 * 95 / 4) * 4, 95) > > #define VDD_FROM_REG(val) (((val) * 95 + 2) / 4) > > > > #define DIV_FROM_REG(val) (1 << (val)) > > Code looks good. Alignment is a bit clumsy though. Also it feels > strange now that you are using DIV_ROUND_CLOSEST for VDD_TO_REG but not > VDD_FROM_REG. > I cleaned up the alignment, and added DIV_ROUND_CLOSEST() to VDD_TO_REG(). I'll resend an updated version. Thanks, Guenter > Reviewed-by: Jean Delvare > > -- > Jean Delvare > SUSE L3 Support