Re: multiboot2 protocol on ARM with ACPI

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2014-09-24 at 20:20 +0200, Daniel Kiper wrote:
> > which we happen to call multiboot which is described at:
> > http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions/Multiboot
> 
> I thought exactly about that. Anyway, name is a bit unfortunate because
> it clashes with name of legacy boot multiboot protocol for x86, MIPS and
> maybe others

This was partially deliberate since we wanted the existing grub.cfg
multiboot syntax ("multiboot <foo>; kernel <bar>; etc") people were used
to (and which the tools generate already) to Just Work.

AFAIK multiboot(1) is mostly x86 specific, or at least will never be
implemented on on ARM. multiboot2 is something else which is newer and
more cross platform[0] and it uses a different grub.cfg syntax
(multiboot2 <foo> I think).

Which is why we felt it would be ok to reuse the multiboot1 grub syntax
for this ARM thing we invented.

Ian.

[0] i.e. supports MIPS and maybe others, possibly including ARM,
although I don't know of anyone who is working on that. Xen on ARM
doesn't really find multiboot2 useful/interesting, although if it became
widely used we would of course think about implementing support for it.

>  which is defined in completely different way. Once I even heard
> that "The thing" is called multiboot2 for ARM. That is why I put multiboot2
> in this email, ehh...
> 
> > Anyway, with that out of the way...
> >
> > ARM systems with ACPI still use DT for certain things, including the
> > initrd and boot modules (stuff which in speak is in the "/chosen node").
> > It's the platform/hardware side of things (i.e. all the stuff
> > outside /chosen on a DT system) which is described via ACPI.
> 
> Thank you for explanation. I thought that this could be done more or
> less in that way but I wanted to be sure.
> 
> Daniel