Fwd: Kexec support for PS3 (ppc64)

[Rajasekaran P]

On Fri, Mar 14, 2008 at 4:02 AM, Mohan Kumar M <mohan at in.ibm.com> wrote:

> On Fri, Mar 14, 2008 at 03:36:58AM -0700, Rajasekaran P wrote:
> > On Tue, Mar 11, 2008 at 11:48 AM, Geoff Levand <
> geoffrey.levand at am.sony.com>
> > wrote:
> >
> > Initially I made mistake by referring /proc/meminfo and thought the
> total
> > RAM was > 200M iB (actually it shows around 211MiB in /proc/meminfo
> > excluding swap space). But actual available memory is 128MiB only. Thats
> why
> > reserving 128MiB on 32MiB failed and kernel was not booting up.
> >
> > Now "crashkernel" argument works properly for 64MB at 64MB and kernel
> reserves
> > 64MB for crash dump capture kernel.
>
> In PPC64, crashkernel base address is hard coded i.e it is always loaded
> at 32MB, even though you have passed 64MB at 64MB. Did you get any warning
> message like crashkernel reserved at 32MB?
>
> >
> > This memory is reserved for "dump capture kernel" which will be loaded
> later
> > by using kexec. Please refer linux_src/Documentation/kdump/kdump.txt for
> > more information.
> >
> > I tried to load dump capture configured kernel and facing similar kind
> of
> > problem. After successful loading, Dump capture kernel is NOT BOOTING UP
> > upon kernel crash.
>
> Do you get any message from the dump capture kernel? How do you trigger
> the dump?
>
> > I used the following command to load:
> >
> > # kexec -t elf-ppc64 --append="video=ps3fb:mode:166 rhgb
> root=/dev/ps3da3
> > single maxcpus=1 noirqdistrib" \
> >  --initrd=/boot/initrd-2.6.23-kdump.img \
> >  -p vmlinux.strip.kdump
>
>         ^^ Is this kernel compiled with CRASH_DUMP enabled? If yes, it
> should build the kernel for 32MB.


>
> > *
> > Output:*
> > *setup_memory_ranges memory_range[0] start:585001, end:8000000
> > get memory ranges:1
> > setup_memory_ranges memory_range[0] start:585001, end:8000000
> > Modified cmdline:video=ps3fb:mode:166 rhgb root=/dev/ps3da3 single
> maxcpus=1
> > noirqdistrib elfcorehdr=71068K savemaxmem=64M
> > segment[0].mem:0x4000000 memsz:5599232
>
>                         ^^ Says the vmlinux is loaded at 64MB
> > segment[1].mem:0x4557000 memsz:65536
> > segment[2].mem:0x4567000 memsz:4096
> > segment[3].mem:0x4568000 memsz:36864
> > segment[4].mem:0x4571000 memsz:3469312
> > segment[5].mem:0x7fff000 memsz:4096
> > *
> > One more thing I confirmed was, this same dump capture kernel boots up
> > properly when I load it on normal mode (kexec -l and then kexec -e). I
> am
> > having no clue on this..
>

Yes,I built this kernel with CRASH_DUMP and VMCORE file system  enabled.
Moreover, I disabled SMP as well.
My system kernel is (First kernel) is SMP enabled, does it matter?

I dont get any message from dump capture kernel.

I trigger crash dump using :

echo c > /proc/sysrq-trigger
Initially capture kernel was loaded into 32MB only, but still it was not
booting. So I tweaked the KDUMP_KERNELBASE macro to load capture kernel to
64MB ( My idea is, first 64MB for system kernel and second 64MB for capture
kernel). Should it be 32MB only?
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