Re: sb_edac 32-bit compile fail due to 64-bit divide

Mauro Carvalho Chehab
2011-11-03T14:32:35Z

Em 03-11-2011 12:07, Josh Boyer escreveu:
> Hi,
>
> It seems the newly added EDAC driver for SandyBridge won't build on
> 32-bit x86 because of a 64-bit divide somewhere:
>
> drivers/edac/sb_edac.c: In function 'get_memory_error_data':
> drivers/edac/sb_edac.c:861:2: warning: left shift count >= width of type
> [enabled by default]
> <snip>
> ERROR: "__udivdi3" [drivers/edac/sb_edac.ko] undefined!
> make[1]: *** [__modpost] Error 1
> make: *** [modules] Error 2
>
> You can find the full build log here:
>
> http://koji.fedoraproject.org/koji/getfile?taskID=3482579&name=build.log
>
> Before I go digging into where this is done and what to do about it, I
> do want to confirm that it is supposed to work on a 32-bit kernel,
> correct?

Thanks for pointing it!

Well, I didn't test it on a 32-bit kernel. It should work through.

It is probably due to those debug lines:
debugf0("CH#%d RIR#%d INTL#%d, offset %Lu.%03Lu GB (0x%016Lx), tgt: %d, reg=0x%08x\n",
i, j, k,
tmp_mb / 1000, tmp_mb % 1000,
((u64)tmp_mb) << 20L,
(u32)RIR_RNK_TGT(reg),
reg);
(same kind of calculus is recurrent at the driver)

Maybe the easiest way would be to write a function that would call do_div() internally,
and output a string with something similar to:

sprintf(msg, "%Lu.%03Lu GB", tmp_mb / 1000, tmp_mb % 1000);

Of course, an interim fix would be to make it depend on CONFIG_64BIT or CONFIG_X86_64.

Regards,
Mauro