Linux boot on a ppc 405

David Baird dhbaird at
Mon Jan 28 05:29:41 EST 2008

On Jan 27, 2008 9:20 AM, Ricardo Severo <severo.ricardo at> wrote:
> Hi all,
> I am working with a Xilinx Virtex II Pro  evaluation board, wich has two
> PowerPC 405 and I'm trying to boot a vanilla linux kernel
> Until now I've manged to make it uncompress the kernel, but it doesn't boot.
> My question is how the initial execution (the one who uncompresses the
> kernel image) transfers the processor to the kernel itself. I've looked
> in the arch/ppc/boot/simple/relocate.S code and it jumps to the position
> 0x0 after uncompressing, is it right? The kernel is uncompressed at that
> position?
> Thanks,

It should branch to the beginning of arch/ppc/kernel/head_4xx.S, which
I think was 0x0.

Some things to check are:

- Comment/remove the weak embed_config in arch/ppc/boot/simple/misc-embedded.c
- Did you use ttyUL0 or ttyS0 as your console?

If that fails, you can use XMD to set a breakpoint at 0x0 and then
read the memory to see if it matches up with an objdump of vmlinux.

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