From: Andy Shevchenko <andy.shevchenko@gmail.com> To: Evgeniy Didin <Evgeniy.Didin@synopsys.com> Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "Alexey.Brodkin@synopsys.com" <Alexey.Brodkin@synopsys.com>, "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>, "dianders@chromium.org" <dianders@chromium.org>, "Vineet.Gupta1@synopsys.com" <Vineet.Gupta1@synopsys.com>, "Eugeniy.Paltsev@synopsys.com" <Eugeniy.Paltsev@synopsys.com>, "linux-snps-arc@lists.infradead.org" <linux-snps-arc@lists.infradead.org>, "stable@vger.kernel.org" <stable@vger.kernel.org>, "ulf.hansson@linaro.org" <ulf.hansson@linaro.org> Subject: Re: [PATCH 2/2 v3] mmc: dw_mmc: Fix the CTO overflow calculation for 32-bit systems Date: Mon, 26 Feb 2018 20:30:41 +0200 [thread overview] Message-ID: <CAHp75VcABGN+awEUzNiTAc985EM0XVS6eiNLGYYD1_vCrRC00Q@mail.gmail.com> (raw) In-Reply-To: <1519665265.31245.6.camel@synopsys.com> On Mon, Feb 26, 2018 at 7:14 PM, Evgeniy Didin <Evgeniy.Didin@synopsys.com> wrote: > On Mon, 2018-02-26 at 18:53 +0200, Andy Shevchenko wrote: >> On Mon, Feb 26, 2018 at 5:14 PM, Evgeniy Didin >> <Evgeniy.Didin@synopsys.com> wrote: >> > On Mon, 2018-02-26 at 16:39 +0200, Andy Shevchenko wrote: >> > > On Mon, Feb 26, 2018 at 4:34 PM, Evgeniy Didin >> > > <Evgeniy.Didin@synopsys.com> wrote: >> > > > In commit 4c2357f57dd5 ("mmc: dw_mmc: Fix the CTO timeout calculation") >> > > > have been made changes which can cause multiply overflow for 32-bit systems. >> > > > The value of cto_ms is lower the drto_ms, but nevertheless overflow can occur. >> > > > Lets cast this multiply to u64 type which prevents overflow. >> > > > - cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); >> > > > + >> > > > + cto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); >> > > >> > > IIRC, someone commented on this or similar, i.e. >> > > >> > > DIV_ROUND_UP_ULL() ? >> > >> > Switch DIV_ROUND_UP macro to DIV_ROUND_UP_ULL is not reasonable >> > because overflow happens on multiply and DIV_ROUND_UP_ULL helps >> > with sum overflow. >> >> Did you try to compile your code for 32-bit target? > Yes, we have compiled code for 32-bit system. > I am wondering why are you asking that? Because I simple didn't believe you. ERROR: "__udivdi3" [drivers/mmc/host/dw_mmc.ko] undefined! ...scripts/Makefile.modpost:92: recipe for target '__modpost' failed make[2]: *** [__modpost] Error 1 +++ b/drivers/mmc/host/dw_mmc.c @@ -409,7 +409,7 @@ static inline void dw_mci_set_cto(struct dw_mci *host) - cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); + cto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); -- With Best Regards, Andy Shevchenko
WARNING: multiple messages have this Message-ID (diff)
From: andy.shevchenko@gmail.com (Andy Shevchenko) To: linux-snps-arc@lists.infradead.org Subject: [PATCH 2/2 v3] mmc: dw_mmc: Fix the CTO overflow calculation for 32-bit systems Date: Mon, 26 Feb 2018 20:30:41 +0200 [thread overview] Message-ID: <CAHp75VcABGN+awEUzNiTAc985EM0XVS6eiNLGYYD1_vCrRC00Q@mail.gmail.com> (raw) In-Reply-To: <1519665265.31245.6.camel@synopsys.com> On Mon, Feb 26, 2018 at 7:14 PM, Evgeniy Didin <Evgeniy.Didin@synopsys.com> wrote: > On Mon, 2018-02-26@18:53 +0200, Andy Shevchenko wrote: >> On Mon, Feb 26, 2018 at 5:14 PM, Evgeniy Didin >> <Evgeniy.Didin@synopsys.com> wrote: >> > On Mon, 2018-02-26@16:39 +0200, Andy Shevchenko wrote: >> > > On Mon, Feb 26, 2018 at 4:34 PM, Evgeniy Didin >> > > <Evgeniy.Didin@synopsys.com> wrote: >> > > > In commit 4c2357f57dd5 ("mmc: dw_mmc: Fix the CTO timeout calculation") >> > > > have been made changes which can cause multiply overflow for 32-bit systems. >> > > > The value of cto_ms is lower the drto_ms, but nevertheless overflow can occur. >> > > > Lets cast this multiply to u64 type which prevents overflow. >> > > > - cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); >> > > > + >> > > > + cto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); >> > > >> > > IIRC, someone commented on this or similar, i.e. >> > > >> > > DIV_ROUND_UP_ULL() ? >> > >> > Switch DIV_ROUND_UP macro to DIV_ROUND_UP_ULL is not reasonable >> > because overflow happens on multiply and DIV_ROUND_UP_ULL helps >> > with sum overflow. >> >> Did you try to compile your code for 32-bit target? > Yes, we have compiled code for 32-bit system. > I am wondering why are you asking that? Because I simple didn't believe you. ERROR: "__udivdi3" [drivers/mmc/host/dw_mmc.ko] undefined! ...scripts/Makefile.modpost:92: recipe for target '__modpost' failed make[2]: *** [__modpost] Error 1 +++ b/drivers/mmc/host/dw_mmc.c @@ -409,7 +409,7 @@ static inline void dw_mci_set_cto(struct dw_mci *host) - cto_ms = DIV_ROUND_UP(MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); + cto_ms = DIV_ROUND_UP((u64)MSEC_PER_SEC * cto_clks * cto_div, host->bus_hz); -- With Best Regards, Andy Shevchenko
next prev parent reply other threads:[~2018-02-26 18:30 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-02-26 14:34 [PATCH 0/2 v3] mmc: dw_mmc: Fix DTO/STO timeout overflow calculation Evgeniy Didin 2018-02-26 14:34 ` Evgeniy Didin 2018-02-26 14:34 ` [PATCH 1/2 v3] mmc: dw_mmc: Fix the DTO timeout overflow calculation for 32-bit systems Evgeniy Didin 2018-02-26 14:34 ` Evgeniy Didin 2018-02-26 14:34 ` Evgeniy Didin 2018-02-26 14:40 ` Andy Shevchenko 2018-02-26 14:40 ` Andy Shevchenko 2018-02-27 1:14 ` Shawn Lin 2018-02-27 1:14 ` Shawn Lin 2018-02-27 1:46 ` Shawn Lin 2018-02-27 1:46 ` Shawn Lin 2018-03-01 1:22 ` kbuild test robot 2018-03-01 1:22 ` kbuild test robot 2018-02-26 14:34 ` [PATCH 2/2 v3] mmc: dw_mmc: Fix the CTO " Evgeniy Didin 2018-02-26 14:34 ` Evgeniy Didin 2018-02-26 14:39 ` Andy Shevchenko 2018-02-26 14:39 ` Andy Shevchenko 2018-02-26 15:14 ` Evgeniy Didin 2018-02-26 15:14 ` Evgeniy Didin 2018-02-26 15:14 ` Evgeniy Didin 2018-02-26 16:53 ` Andy Shevchenko 2018-02-26 16:53 ` Andy Shevchenko 2018-02-26 17:14 ` Evgeniy Didin 2018-02-26 17:14 ` Evgeniy Didin 2018-02-26 18:30 ` Andy Shevchenko [this message] 2018-02-26 18:30 ` Andy Shevchenko 2018-02-26 20:27 ` Alexey Brodkin 2018-02-26 20:27 ` Alexey Brodkin 2018-02-26 20:27 ` Alexey Brodkin 2018-02-27 3:52 ` Jisheng Zhang 2018-02-27 3:52 ` Jisheng Zhang 2018-02-27 10:49 ` Andy Shevchenko 2018-02-27 10:49 ` Andy Shevchenko 2018-02-27 3:02 ` [PATCH 0/2 v3] mmc: dw_mmc: Fix DTO/STO timeout overflow calculation Jisheng Zhang 2018-02-27 3:02 ` Jisheng Zhang 2018-02-27 3:02 ` Jisheng Zhang
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