Re: [PATCH v2] Change the default link address for pSeries zImage kernels.

On Wed, Jul 02, 2008 at 05:04:32PM +0200, Olaf Hering wrote:
 

Setting real-base to what?

32Mb, or any other value big enough to allow the tftp to fit in
${real-base} - ${load-base}.  I admitt it's far from ideal.
 

What currently happens with a large boot file is:
Firmware loads the zImage at load-base, finds that the ELF file is too
large to fit into the memory window and stops.

With your patch, firmware loads 12566528 bytes, and starts the zImage.
The result is a truncated file, the initrd will be corrupted, kernel
panic in populate_rootfs().

Okay that's not the behaviour I see here on the POWER4 machines, they
grab the firt n bytes (probabbly 12566528), and then abort with a
message about image being too large and it cannot be split.
(something akin to https://bugzilla.novell.com/show_bug.cgi?id=350212 )
 

The only system where firmware relocates itself from 12MB to 32MB is a
p640 with firmware version NAN04194.
All other systems seem to ignore the NOTE section, real-base remains at
0xc00000

Add I thought /all/ POWER4 systems were unable to relocate OF
(regardless of whether the request is from the NOTE or from set-env
real-base).
 

So I do not think your patch is a real improvement,
clear error vs. silent corruption.

Do you happen to know how to automate the changing the value of
real-base? The addnote change has appearently no effect on recent
systems.

It's there for POWER5 and on.  I was sure that no POWER4 machines could
be reloacted, but you say that your p640 can.

Yours Tony

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