Re: Decrementer exception, again

["Philip Schulz" <philip.s.schulz%googlemail.com@localhost>]

Hi,

 please note that I'm not a NetBSD user, just following the mailing
lists. Keep that in mind when following my advice.

 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. Also, you're seing it b/c external interrupts are
somehow turned on and the NetBSD exception handlers are not yet set
up.

 So anyways, what happens when you enter

 1 1f lshift not dec!

 at the Open Firmware prompt just before booting? That should set the
decrementer register to the highest possible value. If you're lucky,
then Open Firmware doesn't touch the value and you might have enough
time to boot up to the point where NetBSD's exception handlers are
installed.

 HTH,

  Philip

2008/5/31 Lorenz Minder <lminder%gmx.net@localhost>:
> Hi,
>
> I'm trying to install NetBSD on a TiBook 1GHz, but unfortunately I
> belong to the unlucky crowd of those who get the Decrementer Exception
> when trying to boot.
>
> From reading the mailing list archives, I get the impression that there
> is no known solution to this problem, but is there something I could try
> to get it to run anyway?
>
> A few data points:
>
> * The system runs Linux and OpenBSD 4.3 just fine.
>
> * Here's the output (modulo typos, it's handcopied from screen) when
>  trying the NetBSD 4.0 boot ISO:
>
>        Apple PowerBook3,5 4.5.3f2 BootROM built on 10/25/02 at 10:31:30
>        Copyright 1994-2002 Apple Computer, Inc.
>        All Rights Reserved.
>
>        Welcome to Open Firmware, the system time and date is 08:57:38 
> 05/31/2008
>
>        To continue booting, type "mac-boot" and press return.
>        To shut down, type "shut-down" and press return.
>
>         ok
>        0 > boot cd:,\ofwboot.xcf /netbsd.macppc load-size=c6e4 
> adler32=db469db9
>
>        loading XCOFF
>
>        tsize=c2d0 dsize=234 bsize=29c0 entry=e00000
>        SECTIONS:
>        .text    00e00000 00e00000 0000c2d0 000000e0
>        .data    00e0d000 00e0d000 00000234 0000c3b0
>        .bss     00e0d238 00e0d238 000029c0 00000000
>        loading .text, done..
>        loading .data, done..
>        clearing .bss, done..
>
>        >> NetBSD/macppc OpenFirmware Boot, Revision 1.10
>        >> (builds@wb30, Sat Dec 15 23:31:51 PST 2007)
>        4596796+109808=0x47d480
>         start=0x100000
>
>        Decrementer exception at   %SRR0: 00000036   %SRR1: 00003600
>         ok
>        0 > .registers
>        Client's Fix Pt Regs:
>         00 ff846b58 7c0802a6 1fc46960 0035e8ec 0035678c 00003030 00100234 
> 00563c38
>         08 00000000 00360000 b000002a 00000008 42000024 00000000 00000000 
> 00000000
>         10 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
> 00000000
>         18 00000000 00000000 00560000 0056b06c 0030dda8 ff883d88 00000100 
> 0035e8ec
>        Special Regs:
>            %IV: 00000000   %SRR0: 00000036   %SRR1: 00003600
>            %CR: 0000b000     %LR: 00360000    %CTR: 360000b0   %XER: 00b00000
>           %DAR: b000002a  %DSISR: 00002a00   %SDR1: 42000024
>          %HID0: 00000000   %HID1: 00000000   %L3CR: 00000000  %L2CR: 00000000
>         %ICTRL: 00000000 %LDSTDB: 00000000 %LDSTCR: 00000000 ok
>        0 >
>
>  * I built -current kernel (as of two days ago), and tried to boot that
>   one (I used OpenBSD's bootloader though, is that ok for this?) and I
>   still get the same Decrementer Exception.
>
> Best,
> --Lorenz
>