Subject: Re: [PATCH] sfc_ef100: Fix build failure on powerpc

From: Segher Boessenkool <[email-masked]>
Date: Thu, 13 Aug 2020 10:57:27 -0500

On Thu, Aug 13, 2020 at 02:39:10PM +0000, Christophe Leroy wrote:
> ppc6xx_defconfig fails building sfc.ko module, complaining
> about the lack of _umoddi3 symbol.
> 
> This is due to the following test
> 
>  		if (EFX_MIN_DMAQ_SIZE % reader->value) {
> 
> Because reader->value is u64.
> 
> As EFX_MIN_DMAQ_SIZE value is 512, reader->value is obviously small
> enough for an u32 calculation, so cast it as (u32) for the test, to
> avoid the need for _umoddi3.

That isn't the same e.g. if reader->value is 2**32 + small.  Which
probably cannot happen, but :-)

Segher