[PPC] t1024rdb: CONFIG_KERNEL_START=0x0 equivalent for ppc64 (Kernel 3.16.85)

[Alex Fetzner]

Thanks Christophe

> > How do I appropriately alter a ppc64 kernel to have entry point 0x0?
After working with the issue further, I determined my original question was 
ill-formed because I had an incomplete understanding. 

> Even with the CONFIG_KERNEL_START you can't expect any kernel to have a
> virtual start address of 0, because the KERNEL needs to be above user space.
>
> But you shouldn't need that. It is the role of the loader to set the MMU
> so that the kernel is running with the correct virtual address.
> 
> I don't understand why you need the virtual starting address of vmlinux
> to be 0x0.
Indeed, it doesn't make sense for kernel start address 0x0.
As I am trying to make a stand-in for another kernel image without changing
the U-Boot load address, I saw that the original vmlinux ELF header had
Entry point address: 0x0 
But critically, as I now understand, it also had 
Type: DYN , not EXEC

What I determined is that I needed CONFIG_RELOCATABLE=y; I did not need to
alter the load address. After making a relocatable kernel, I was able to get 
it to boot on my hardware.

> 
> Here is what I get with ppc64e_defconfig with v6.18-rc1:
>
Thank you for taking the time to find this for me.

Kind regards,
Alex