Re: Decrementer exception, again

[Lorenz Minder <lminder%gmx.net@localhost>]

Hi,

Thanks for the input! It is very much appreciated.

Philip Schulz wrote:
>[...]
>  I think the exception you're seeing is being handled by Open
> Firmware, i.e. the "Decrementer exception at ..." stuff is Open
> Firmware's output.

Yes, agreed.

>[...]
>  So anyways, what happens when you enter
> 
>  1 1f lshift not dec!
> 
>  at the Open Firmware prompt just before booting?

Interesting!  Very good suggestion.

This does indeed change something. Now I reliably get

Invalid memory access at   %SRR0: 00000036   %SRR1: 00003600

I have tried this roughly a dozen times, and now it appears to be always
this, and never the decrementer exception.  Previously I would also
sometimes get the invalid memory access, but rarely.

Curiously enough, the values for SRR0 and SRR1 are the same as for the
decrementer exception that I previously had.

I've now also tried booting 1.6, 2.0 and 3.0 Kernels, but none of
them with success. And I gave Antoine Reilles' NOP-patches [1] a shot,
no success either.

I should say that a single time (with the 2.0) Kernel, it actually
started a console and dropped me into the kernel debugger immediately.
I was not able to reproduce this despite trying many times, though.

I believe this is PR 22316 [2].

Best,
--Lorenz


[1] http://mail-index.netbsd.org/port-macppc/2006/02/13/0009.html
[2] http://www.NetBSD.org/cgi-bin/query-pr-single.pl?number=22316