Re: 2.6.x on 405CR

On Tue, Sep 28, 2004 at 11:57:44AM +0200, Piotr Perak wrote:

On Mon, 27 Sep 2004, Matt Porter wrote:

quoted

Since you are failing in ocp_add_one_device() and you have a
processor which doesn't have a chip definition in 2.6, the
problem is probably somewhere there.  Doublecheck your
arch/ppc/platforms/4xx/ibm405cr.c (you do have one, right?)
against a known good one in arch/ppc/platforms/4xx/ibm405gp.c

Because I use ibm405cr.c which works good with 2.4.23 I think that's not
the problem. Remember the call stack?

Which 2.4 tree?  linux-2.4, linuxppc-2.4, and linuxppc_2_4_devel haven't
had explicit 405cr support that I've noticed. Since the ocp layer has
changed that would leave open the possibility of a problem in translating
the support to the new ocp layer. 

setup_arch() - arch/ppc/kernel/setup.c
  -> ocp_early_init() - arch/ppc/syslib/ocp.c
    -> ocp_add_one_device() - arch/ppc/syslib/ocp.c
      ->  alloc_bootmem MACRO calling __alloc_bootmem_core() -
mm/bootmem.c

When I comment line calling ocp_early_init() I fail in:
 
setup_arch() - arch/ppc/kernel/setup.c
  -> paging_init() - arch/ppc/mm/init.c
    -> free_area_init() - arch/ppc/mm/page_alloc.c
      -> free_area_init_node() - arch/ppc/mm/page_alloc.c
        -> alloc_bootmem_node() MACRO calling __alloc_bootmem_node -
mm/bootmem.c
          -> __alloc_bootmem_core() - mm/bootmem.c

As you can see again __alloc_bootmem_core. So maybe there's some
problem with memory?

Hrm, I see. Did your firmware change between your working 2.4 kernel
and your non-working 2.6 kernel?  If you're failing in there that would
be my first thought. I suppose that's probably not that case though.

Forgive me if I ask stupid questions, but this the first time I have
something to do with the kernel (not counting compiling for my home PC).

Well, the 405cr support issue is really throwing me for a loop here. If
you're crashing in _alloc_bootmem_core() and haven't hacked any MM code
then you're an interesting spot.  Can you trace it down to the exact
failure in __alloc_bootmem_core?

-Matt

On Tue, 28 Sep 2004, Matt Porter wrote:

On Tue, Sep 28, 2004 at 11:57:44AM +0200, Piotr Perak wrote:

quoted

Because I use ibm405cr.c which works good with 2.4.23 I think that's not
the problem. Remember the call stack?

Which 2.4 tree?  linux-2.4, linuxppc-2.4, and linuxppc_2_4_devel haven't
had explicit 405cr support that I've noticed. Since the ocp layer has
changed that would leave open the possibility of a problem in translating
the support to the new ocp layer.

linux-2.4 ported to our board some time ago.  

quoted

setup_arch() - arch/ppc/kernel/setup.c
  -> ocp_early_init() - arch/ppc/syslib/ocp.c
    -> ocp_add_one_device() - arch/ppc/syslib/ocp.c
      ->  alloc_bootmem MACRO calling __alloc_bootmem_core() -
mm/bootmem.c

When I comment line calling ocp_early_init() I fail in:
 
setup_arch() - arch/ppc/kernel/setup.c
  -> paging_init() - arch/ppc/mm/init.c
    -> free_area_init() - arch/ppc/mm/page_alloc.c
      -> free_area_init_node() - arch/ppc/mm/page_alloc.c
        -> alloc_bootmem_node() MACRO calling __alloc_bootmem_node -
mm/bootmem.c
          -> __alloc_bootmem_core() - mm/bootmem.c

As you can see again __alloc_bootmem_core. So maybe there's some
problem with memory?

Hrm, I see. Did your firmware change between your working 2.4 kernel
and your non-working 2.6 kernel?  If you're failing in there that would
be my first thought. I suppose that's probably not that case though.

2.4.23 still runs on board I try to port 2.6.8.1 to. So I guess firmware
is not the problem?

Well, the 405cr support issue is really throwing me for a loop here. If
you're crashing in _alloc_bootmem_core() and haven't hacked any MM code

I haven't change any MM code.

then you're an interesting spot.  Can you trace it down to the exact
failure in __alloc_bootmem_core?

I already did it. Can you please read
http://ozlabs.org/pipermail/linuxppc-dev/2004-September/000104.html? I
described there what weird things are happening in __alloc_bootmem_core.

Piotr Perak