[fedora-arm] Broken sha512sum in coreutils / forcing alignment fixup and logging in initscripts

[Andy Green]

On 01/08/11 09:54, Somebody in the thread at some point said:
> On 01/08/2011 02:49 AM, Chris Tyler wrote:

>> Related proposal: I think we should have the startup scripts
>> set /proc/cpu/alignment to 3 (warn+fixup) by default in Fedora-ARM (we
>> do this on the Koji builder image). I don't see a downside, and there's
>> a definite upside on armv5 systems.
>
> I see a number of downsides to this:
>
> 1) There is a performance hit.
> 2) It 's a workaround, not an actual fix. The code causing these
> problems should be fixed properly.

I don't see any downside to what Chris is suggesting, I think it's a 
good idea.

The only thing is there's a little window where without the kernel 
parameter and before the script sets it, whatever is running could 
fault.  But there should be a little and consistent set of stuff running 
at that time which does not make alignment faults at the moment.

> I would like to offer a counter-proposal - no package is accepted into
> Fedora (ARM?) until it stops generating misalignment warnings. That way

I think your proposal is a bad idea.

That does not help the guy who is rolling his own software and doesn't 
know about this alignment issue, like, eg, yourself of yesterday who 
just gets rubbish sometimes.  In some cases he might only get rubbish 
one in a million tries, we are not helping him leaving him in that 
situation.

It's much better to give that guy consistent results in data terms and 
erratic performance; if he cares he can google it.

That's especially true now I learned from this that more modern ARM 
cores are fixing it up silently in hardware anyway, it just brings 
earlier cores like mine into acting the same which is all good.

So I think Chris' idea sounds good.

-Andy