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On Mon, Feb 13, 2006 at 07:00:54AM -0800, 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
> >=20
> > 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=20
> > also PR #22316.
> >=20
> > 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 ?
>=20
> 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. =20
It tried it because that was the only lines in openbsd's ofwinit for
which i could reasonably think they would not make things even worse
than what they were
> 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?
I just tried to replace the four statements i added before by nop, and
it looks good: at least, 1 try, 1 success. I tried the previous patch
with different builds, for several different config, and got 100%
success.

antoine

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