I'm trying it now...does this compell a rebuild of ofwboot, the kernel, or 
both?  I'm trying to avoid the netbsd-4 build world ~BAS

On Mon, 13 Feb 2006, Chuck Silvers wrote:

> On Fri, Feb 10, 2006 at 02:33:42PM +0100, Antoine Reilles wrote:
>> After looking at the ofwinit routine in openbsd, I tried to add code to
>> save and restore return address, and now, i can boot a GENERIC macppc
>> kernel on my powerbook 6,8
>>
>> I don't exactly know why it was not working before, neither why exactly
>> it does not, but so far three different kernels with different config,
>> but the same tweak to boot without problem.
>> It is also surely related to the problem Olivier was experiencing
>> (http://mail-index.netbsd.org/port-macppc/2005/12/27/0001.html),
>> or davide
>> (http://mail-index.netbsd.org/port-macppc/2004/08/30/0010.html), and
>> also PR #22316.
>>
>> Here the patch i used.
>> I borrowed those lines from openbsd, so they use %r, since they
>> converted all their assembly to that.
>> Can someone who has a clue please look at it ?
>
> the openbsd version of this code saves and restores those caller-saved
> registers around calling some functions (savemmu and save_ofw_mapping).
> since ofwinit() in netbsd doesn't call any functions (outside the
> FIRMWORKSBUGS case, which does its own save-and-restore dance and
> is not enabled for macppc), saving and restoring those registers
> is not necessary.  if this change really is making a difference for you,
> then I would guess that it's because it changes the position of the
> instructions that come after your change.  if that's true, then adding
> the same number of nop instructions instead of the other instructions
> would work just as well.  could you give that a try?
>
> -Chuck
>

l8*
 	-lava (Brian A. Seklecki - Pittsburgh, PA, USA)
 	       http://www.spiritual-machines.org/

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