[OpenBIOS] Running client with MMU off

Mark Cave-Ayland mark.cave-ayland at ilande.co.uk
Fri Jun 20 23:52:46 CEST 2014


On 19/06/14 22:19, BALATON Zoltan wrote:

> With the patch below I don't get DSI-s but it crashes in an ISI while
> trying to replace the sr registers. How could this possibly work on real
> hardware without getting any exceptions during replacing the vectors? Is
> there a way to preload the TLB with code addresses too so we can avoid
> the crash? How? (For data accessing it before calling the boot code is
> enough to preload translations but how to avoid ISI-s?)

Unfortunately, as far as I know there are only a few PPC processors that 
allow you to lock entries in the TLB and none of them were used in Macs.

As for the code that generates the ISIs, is this in MorphOS as opposed 
to OpenBIOS? I guess something must have previously accessed an entry on 
the same page before the registers were updated, or maybe there is some 
kind of hardware readahead?


ATB,

Mark.




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