[PATCH] kexec:arm: support zImage with appended device tree

[Hoeun Ryu]

On Tue, 2017-07-04 at 09:41 +0800, Dave Young wrote:
> On 07/03/17 at 05:41pm, Russell King wrote:
> > 
> > On Tue, Jun 27, 2017 at 06:51:50PM +0900, Hoeun Ryu wrote:
> > > 
> > > > 
> > > > What about the initrd?  Do you want to append that as well?
> > > I have thought of it.
> > > I think It would be better to have it.
> > > But I think this is the first step to do so.
> > That is something we don't support with the kernel, and would be
> > insane
> > to do so - it would mean that the very dumb decompressor would have
> > to relocate not only the dtb image, but also the initrd image to
> > some other part of memory.  It moves the appended dtb image along
> > with
> > the rest of the zImage as one complete blob, but that doesn't work
> > so well for an appended initrd.  It will also be rather slow.
> > 
> > So I'd like to continue my discouragement of this entire approach
> > and
> > say that kexec-tools should *not* add support for an appended DTB
> > nor
> > an appended initrd.
> I also agree that we'd better not adding this in kexec-tools, --dtb
> works well, the appended dtb does not gain much but it introduces
> more
> code to maintain.
> 

I understand and respect your opinion.
Thank you for the review.

> > 
> > 
> > The kernel build process gives you the kernel image and dtb file.
> > The appended-dtb image support that we have in the kernel is for
> > backwards compatibility with non-DT aware boot loaders that only
> > know how to deal with one or two images at boot time.
> >