Re: Design doc of adding ACPI support for arm64 on Xen - version 2

[Julien Grall <julien.grall@citrix.com>]

On 12/08/15 12:23, Ian Campbell wrote:
> Strictly it is considered a separate thing, much like loader.efi, despite
> where it lives e.g. it is self contained and not allowed to call into the
> kernel proper except via the formal interface provided for the hand-off.
> 
> That might seem like semantic quibbling, but I just want to clarify that
> the Linux and BSD approaches here are basically the same.
> 
> Given that these device tree bindings are really just Linux's equivalent of
> the "a format the kernel understands" which BSD uses as described above. I
> don't know what format BSD uses, Linux just happened to have a DTB library
> handy...

IIRC, on FreeBSD, the loader and the kernel is talking through a custom
format called metadata. There is no modification of device tree by the
loader.

Although, I would prefer to see a common interface between Xen and DOM0
rather than implementing a custom one for each OS we will support.

I have to think how everything will work together. AFAIK, on x86, the
loader is loading Xen and the FreeBSD kernel in the memory. The metadata
necessary for the kernel is passed as a multiboot entry.

I will speak with Royger to see what we can do here.

In the meantime, I think we should drop "linux," when we standardize
them to show that they are generic and not linux specific.

Regards,

-- 
Julien Grall