Building a small sparc32 kernel

Building a small sparc32 kernel

[Ludovic Courtès]

Hello,

I'm trying to build a 2.6.11 kernel with Bob Breuer's sparc32 SMP
patch[0] for a bi-processor SS20 (currently running a 2.4 SMP kernel).
I'm having a hard time trying to figure out an appropriate build
configuration such that the resulting kernel image is small enough
(i.e., avoiding the "uncompressed image too long" message at boot time).

Does anyone have an appropriate `.config' that may be posted?

Thanks,
Ludovic.

[0] http://article.gmane.org/gmane.linux.ports.sparc/5650/

Re: Building a small sparc32 kernel

[Bob Breuer]

Ludovic Courtès wrote:
> Hello,
> 
> I'm trying to build a 2.6.11 kernel with Bob Breuer's sparc32 SMP
> patch[0] for a bi-processor SS20 (currently running a 2.4 SMP kernel).

2.6.11?  You shouldn't need to go back that far.  The patch in the
message you referenced was for 2.6.14, and also works for 2.6.15.  As
long as you don't enable spinlock debugging, you will never get the lock
errors.

> I'm having a hard time trying to figure out an appropriate build
> configuration such that the resulting kernel image is small enough
> (i.e., avoiding the "uncompressed image too long" message at boot time).
> 
> Does anyone have an appropriate `.config' that may be posted?
> 

It's nearly a requirement for the kernel to be stripped before silo will
load it.  Try using "strip arch/sparc/boot/image -o /boot/vmlinux" to
copy and strip the kernel in one step.

Bob

> [0] http://article.gmane.org/gmane.linux.ports.sparc/5650/

Re: Building a small sparc32 kernel

[Ludovic Courtès]

Hi,

2 days, 21 hours, 9 minutes, 50 seconds ago, 
Bob Breuer wrote:
> 2.6.11?  You shouldn't need to go back that far.  The patch in the
> message you referenced was for 2.6.14, and also works for 2.6.15.  As
> long as you don't enable spinlock debugging, you will never get the lock
> errors.

Right.  I really meant 2.6.14.

> It's nearly a requirement for the kernel to be stripped before silo will
> load it.  Try using "strip arch/sparc/boot/image -o /boot/vmlinux" to
> copy and strip the kernel in one step.

Oh yes, I had skipped this step.

So, I now have a 2.6.14 SMP kernel I can boot from.  On my SS20, it
doesn't even get to the point of spawning `init'.  I get a number of the
following messages at boot time:

  esp0: Resetting scsi bus
  esp0: SCSI bus reset interrupt
  esp0: DMA error a4400302

And finally, I get spinlock debugging messages followed by a stack trace
telling that something went wrong ("BUG: spinlock lockup on CPU#2",
etc.), and nothing more.  I guess I'm going to have to capture the
console output via a serial line in order to provide you with meaningful
data.

The machine has two SuperSPARC 390Z50.  In your original message you
mentioned that support for SuperSPARC II was relatively stable, so maybe
this just means that support for this older SuperSPARC flavor is not yet
in such a good shape?  ;-)

Let me know how I can help with this.

Thanks,
Ludovic.

Re: Building a small sparc32 kernel

[Wolfram Quester]

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Hi altogether!

On Sat, Apr 08, 2006 at 04:24:28PM +0200, Ludovic Courtès wrote:
[...snip...]
> 
> The machine has two SuperSPARC 390Z50.  In your original message you
> mentioned that support for SuperSPARC II was relatively stable, so maybe
> this just means that support for this older SuperSPARC flavor is not yet
> in such a good shape?  ;-)

Probably I'm wrong but wasn't there an issue with the 390Z50 not having
cache (in contrast to Z55) an thus not being supported in SMP mode?

With best regards,

Wolfi
> 
> Let me know how I can help with this.
> 
> Thanks,
> Ludovic.
> 
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Re: Building a small sparc32 kernel

[Ludovic Courtès]

Hi,

Yesterday, 14 hours, 55 minutes, 19 seconds ago, Wolfram Quester wrote:
> Probably I'm wrong but wasn't there an issue with the 390Z50 not having
> cache (in contrast to Z55) an thus not being supported in SMP mode?

Well, 2.4 SMP perfectly runs on this machine.  :-)

Thanks,
Ludovic.

Re: Building a small sparc32 kernel

[Bob Breuer]

Ludovic Courtès wrote:
> So, I now have a 2.6.14 SMP kernel I can boot from.  On my SS20, it
> doesn't even get to the point of spawning `init'.  I get a number of the
> following messages at boot time:
> 
>   esp0: Resetting scsi bus
>   esp0: SCSI bus reset interrupt
>   esp0: DMA error a4400302

Are you using multiple drives?  I've seen this problem before when using
multiple drives, even with a 2.6 UP kernel, but I've not had a problem
when only actively using one drive.

> And finally, I get spinlock debugging messages followed by a stack trace
> telling that something went wrong ("BUG: spinlock lockup on CPU#2",
> etc.), and nothing more.  I guess I'm going to have to capture the
> console output via a serial line in order to provide you with meaningful
> data.

Try configuring the kernel with spinlock debugging turned off.

> The machine has two SuperSPARC 390Z50.  In your original message you
> mentioned that support for SuperSPARC II was relatively stable, so maybe
> this just means that support for this older SuperSPARC flavor is not yet
> in such a good shape?  ;-)

I think you're almost there.  I don't see any reason why a pair of older
SuperSPARCs wouldn't work, but I don't have any to test against.

Bob

Re: Building a small sparc32 kernel

[Ludovic Courtès]

Hi,

9 days, 5 hours, 9 minutes, 57 seconds ago, 
Bob Breuer wrote:
> Are you using multiple drives?  I've seen this problem before when using
> multiple drives, even with a 2.6 UP kernel, but I've not had a problem
> when only actively using one drive.

I tried to remove an SCSI disk but this did not yield any noticeable
change.

I also tried to apply a change that was made to `esp_reset ()' in 2.6.16
but that did not improve anything either [0].

Any idea of what else could go wrong?  Maybe my kernel config is broken
in some obvious way?

> Try configuring the kernel with spinlock debugging turned off.

Hmm, I'll try that, but (i) that shouldn't make a big difference and
(ii) the whole point of trying out your patch is to get more information
on what goes wrong, isn't it?  ;-)

Thanks,
Ludovic.

[0] http://lists.debian.org/debian-sparc/2006/04/msg00081.html

Re: Building a small sparc32 kernel

[David S. Miller]

From: Ludovic Courtès <ludo@chbouib.org>
Date: Tue, 18 Apr 2006 23:15:53 +0200

> Any idea of what else could go wrong?  Maybe my kernel config is broken
> in some obvious way?

I doubt it, something is definitely horked in the esp driver
but I personally don't have any time to look into it right
now.