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);