[RFC v3 PATCH 0/4] Relocatable kernel support for PPC64

Mohan Kumar M mohan at in.ibm.com
Fri Jul 18 04:33:39 EST 2008


Hi,

Following four patches enable the "relocatable kernel" feature for
PPC64 kernels.
	1. extract_relocation_info.patch
	2. relocation_build.patch
	3. apply_relocation.patch
	4. relocation_support.patch

With the patchset, vmcore image of a crashed system can be captured
using the same kernel binary.

Still the kernel is not a fully relocatable kernel. It can either run at
0 or 32MB based on which address its loaded. If its loaded by 'kexec -p',
it behaves as a relocatable kernel and runs at 32MB(even though its
compiled for 0). If the same kernel is loaded by yaboot or kexec -l, it
will behave as a normal kernel and will run at the compiled address.

Difference between v3 and v2
* Relocatable kernel build process is integrated with the kernel
  build.
* The problem kdump kernel boot fail on some specific systems is fixed now.

Issues:
* Relocatable vmlinux image is built in arch/powerpc/boot as
  vmlinux.reloc. But it should be built in top level directory of kernel
  source as vmlinux instead of vmlinux.reloc

* During kdump kernel boot, all secondary processors are stuck up. But
  during yaboot all secondary processors are brought online.

Tested on POWER5 systems.

Please send me your suggestions and feedbacks.

Regards,
Mohan.



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