On Tue, 24 Apr 2001, Louis Gerbarg wrote:

> On Tue, 24 Apr 2001, Tsubai Masanari wrote:
> 
> > >> 4. Does the kernel expect to be in real-mode on entry
> > >
> > >Blah. Haven't looked at low-level ppc stuff in too long. Does "real
> > >mode" mean no memory mapping? If so, then yes.
> > 
> > No.  OF needs virtual-mode on PowerMac.
> > So, the kernel must be in virtual-mode on startup too.
> 
> Interesting. Mac OS X comes up with all no translations enabled. The
> reason was explained on the Darwin list last night (>> is me, > is Josh
> de Cesare, who wrote BootX and a number of OF patches Apple distributes):

As Sanjay mentioned, one of the first things the kernel does is disable
translations. :-) So they need to be set up in a 1-1 mapping.

> So, I am not going to get that changed. As I see it I have a couple of
> options. One, I can drop the endeavor. Two, I can try to make an alternate
> entry vector for the NetBSD kernel that sets up some the translation
> mechanism (this will deprive the kernel of the OF CI though). I can also
> attempt to make BootX detect NetBSD kernels, and alter its behaviour (do
> you guys place anything special in a note section, or something like
> that?). The later is probably the simplest, though it is not the cleanest.
> Josh seems pretty convinced the Old World OF CI can not be used reliably
> in a general manner, I would what your thoughs on the issue.

I think alternalte entry points would be fine, especially with some code
which fakes up an OF interface. We have expressed an interest in working
with NuBus machines, and they too don't have OF. So adding an OF-less
entry point would be a good thing. :-)

Take care,

Bill