[OpenBIOS] r638 - in trunk/openbios-devel/forth: bootstrap device
Tarl Neustaedter
Tarl.Neustaedter at Sun.COM
Fri Dec 4 01:58:33 CET 2009
Mark Cave-Ayland wrote:
> Tarl Neustaedter wrote:
>
>>> Continuing to work on Milax, I've found out that the infinite loop
>>> bug I'm getting here is because of an MMU problem - two different
>>> virtual addresses appear to be mapped to the same physical address.
>>
>> I believe that's legal. I know that OBP used to do that on sun4s
>> systems.
>
> Oh that's interesting to know; however in this case I'm fairly
> confident it's broken :( What happens is that first the volume
> descriptor is read from the ISO image into a special buffer, and
> subsequent reads for file entries should then go into a different
> buffer. Unfortunately the subsequent reads into the second buffer seem
> to be mapped to the same memory location
Ah. So the problem isn't that you have two virts->one phys, but that you
expect your two virts to have different physical backing, and they don't.
Yup, that's a bug :-)
More information about the OpenBIOS
mailing list