MOL and OSX on PPC604

[Samuel Rydh]

On Wed, Jul 02, 2003 at 06:31:46PM -0400, Dan A. Milisic wrote:
> People running Xpostfacto have this issue to address as well if they use a
> 604e.  The same 'fix' will allow MOL and native OSX to work on the 604e.  
> 
> Just for laughs I installed MOL on an 8600 with a G3/250.  Installation went
> fine.  Then I popped in the 604e processor and it died seconds after
> startmol.  
> 

Well, there is actually a bug in MOL which prevents mol/604e from
running OSX. Currently, mol/604 handles mtspr/mfspr instructions
targeting the following registers

	UMMCR0, UMMCR1, THRM1, THRM2, THRM3, ICTC, L2CR

as illegal rather than privileged (they are illegal on the 604
but privileged on the G3). I thought I had addressed this issue some
time ago, but after reviewing the code I noticed noticed it was
rather an analogous problem concerning the 7455 I fixed.

In any case, I'll fix right away (only a few lines of code is needed).
Unfortunately this does not help the non-MOL case... nop-ing out
the offending instructions is probably their best bet.

/Samuel