f11 ppc64 woes

[Josh Boyer]

On Sat, Jun 06, 2009 at 05:27:49AM -0700, Roland McGrath wrote:
>I reproduced what jwb reported on the powerstation.
>Mine is with F10 + updates userland, only the kernel seems to matter.
>The test case is:
>
>	# modprobe iscsi_tcp
>	Illegal Instruction
>	#
>
>On -16[278], same oops that jwb saw, wrong text appearing at a page boundary.
>
>This kernel:
>http://kojipkgs.fedoraproject.org/scratch/roland/task_1396640/kernel-vanilla-2.6.29.4-168.fc11.ppc64.rpm
>
>does not exhibit the problem.  That should be all the same buildroot stuff,
>and 2.6.29.4 with no extra patches.
>
>OTOH, this kernel:
>http://kojipkgs.fedoraproject.org/scratch/roland/task_1396192/kernel-2.6.29.4-167.fc10.ppc64.rpm
>
>also does not exibit the problem.  That is normal -167 with all the same
>patches, but built in dist-f10-updates-candidate buildroots.
>
>But contrary to jwb's reports:
>On my powerstation 2.6.29.3-159.fc11.ppc64 fails to boot:

That's not contrary.  We were testing on different machines.  I was testing on
a Apple PowerMac7,2 (dual ppc970 G5) which uses sata_swv for storage, not ipr.

>This is obviously a variant of the same problem.  

Right.

>It's losing on clobbered instructions at a page boundary.

Yes, seems so.

>Man but these bastards boot slow.

I've noticed that about the powerstation, yes.  The G5 boots surprisingly
quick with F11.  Go figure.


>Oh, and note the two variant crashes in different kernels are in different
>routines in different builds, but always at PC 0xc000000000400000,
>and always clobbered the next few words with:
>	00001010 00000008 00001013 0000000f 
>
>The magic PAGE_OFFSET+4MB effect.  So, youse gots to wonder, and...
>
>On 2.6.29.3-142.fc11.ppc64, which has "no problem", I built the appended module.
>It printed this:
>
>Instruction dump:
>e8090000 f8410028 7f83e378 e9690010 7fa5eb78 7c0903a6 e8490008 4e800421 
><00001010> 00000008 00001013 0000000f 7961626f 6f740000 00101600 00000c00 
>				      ^^^^^^^^ ^^^^ <-- spells "yaboot"
>00000400 00101100 00000800 7fa3eb78 4bfff24d 60000000 38600000 383f00b0 
>	 	  	   ^^^^^^^^ <-- goes to correct text again from here
>
>The magic 44 bytes of bogon at PAGE_OFFSET+4MB effect.
>We have no idea how long we have been screwed.
>
>I updated to yaboot-1.3.14-12.fc11.ppc (was f10), ran ybin, no help.

ybin isn't needed on the powerstation iirc.  Anyway, that is indeed odd.

We should have Tony take a look at this if possible.  Or if David can remeber
how to do a netboot directly from OF (and skipping yaboot), that would be a
good test too.

josh