On Mon, Oct 03, 2005 at 09:15:52AM -0400, Daniel Jacobowitz wrote:
> > > Well, the flag is not really to specify whether the common code is to be
> > > used or not. It's about whether the TLB is like that of the R4k.
> > > Actually it's always been a mystery for me why the common code cannot be
> > > used for the SB1, but perhaps there is something specific that I could
> > > only discover in that "SB-1 Core User Manual" that I yet have to see,
> > > sigh...
> > >
> > > Of course if your TLB is indeed different from that of the R4k, then you
> > > shouldn't be setting cp0.config.mt to 1 in the first place...
> >
> > The reason was primarily the tiny bit of extra performance because the
> > SB1 doesn't need the hazard handling overhead. Also tlb-sb1 has a few
> > changes that are needed to initialize a TLB in undefined state after
> > powerup. That was needed to run Linux on firmware-less SB1 cores.
>
> FYI, all I have is a piece of hard evidence: this patch was the
> difference between not booting and booting for a Sentosa with CFE.
> Which isn't firmwareless and isn't a tiny bit of extra performance
> issue.
>
> I'll try to give CVS HEAD a shot this week sometime.
Just as reminder for everybody - CVS is dead and frozen, the action is
playing on git now ...
Ralf
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