initrd problems

Sébastien Côté scote1 at
Sat Jan 20 04:22:43 EST 2001

Matt Porter wrote:
> > I was also wondering if I loaded the kernel correctly.  I put my
> > zImage+initrd (zvmlinux.initrd) at address 0 of ram.  Since I compiled
> > the kernel with debug symbols, it takes a few Megs... Could it be too
> > large for it's own good?  Maybe somebody knows about the answer to that
> > one!
> What does the bootloader show when it relocates the zImage and initrd?
> How about a progress dump so we have something to help you with?  You
> make some comments about not using a special bootloader then say
> you are loading a zImage (from the Sandpoint port) which does have
> a relocating bootloader.  This smells like a custom board port where
> you've gutted or dropped a bootloader and don't have the r3-r6 set
> up correctly for entry into arch/ppc/kernel/head.S.  Are you really
> just dropping vmlinux at address 0?  Details details...

I'll try to see what happens when the image is moved now that I know
this might be the problem, but my stupid debugger isn't friendly at all
and it's very difficult to do so.

I tought the image wouldn't be moved if I placed it a address 0.  I copy
my zvmlinux.initrd at this address so I tought it wouldn't be used.
This is indeed a custom board and I'm really just dropping vmlinux at
address 0.

I also found out that the values of initrd_start and initrd_end aren't
valid when assigned from r4 and r5, so something must be overwriting
these values (intrd_end is smaller than initrd_start)

What's the use for r3?  I read it's board identification but I don't
really care if my board isn't identified correctly (for now at least).
A looked for documentation about this but couldn't find any (the booting
process of linux on a PowerPc seems to be terribly undocumented)

Thanks for your help,

Sébastien Côté

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