[PATCH 00/15] Backport 8xx TLB to 2.4

Joakim Tjernlund joakim.tjernlund at transmode.se
Wed Jun 15 17:43:00 EST 2011


Willy Tarreau <w at 1wt.eu> wrote on 2011/06/14 21:31:06:
>
> Hi Joakim,
>
> On Tue, Jun 14, 2011 at 03:54:45PM +0200, Joakim Tjernlund wrote:
> > This is a backport from 2.6 which I did to overcome 8xx CPU
> > bugs. 8xx does not update the DAR register when taking a TLB
> > error caused by dcbX and icbi insns which makes it very
> > tricky to use these insns. Also the dcbst wrongly sets the
> > the store bit when faulting into DTLB error.
> > A few more bugs very found during development.
> >
> > I know 2.4 is in strict maintenance mode and 8xx is obsolete
> > but as it is still in use I wanted 8xx to age with grace.
>
> OK, I'm not opposed to merge these patches and I really welcome your
> work and want to thank you for having done it. However, I have
> absolutely *zero* skills on ppc, so I want to ensure that someone
> (possibly you) will be able to back me up in case of reported
> regressions once these patches are merged. Since you say that the
> code works on your board, I'm not much worried but at least Dan's
> comment about the risk of performance regression has to be considered.
> If we all agree that it's a tradeoff between performance and stability
> or security, then that's a different matter of course !

Yes, I will still be here :) If there are any regressions I will help out. If
we can't fix it, we can easily back these changes out. I guess I and
Dan will come to some agreement soon and I will post additional, if needed,
patches on top of what I already sent once Dan is happy.

 Jocke



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