[PATCH] arm64: booting: Require placement within 48-bit addressable memory

[Mark Rutland]

On Mon, Nov 14, 2022 at 02:33:52PM +0100, Ard Biesheuvel wrote:
> On Mon, 14 Nov 2022 at 13:10, Mark Rutland <mark.rutland at arm.com> wrote:
> >
> > On Mon, Nov 14, 2022 at 12:58:10PM +0100, Ard Biesheuvel wrote:
> > > +  Bit 3-4    Kernel physical placement
> > >
> > >                       0
> > >                         2MB aligned base should be as close as possible
> > >                         to the base of DRAM, since memory below it is not
> > >                         accessible via the linear mapping
> > >                       1
> > > +                       2MB aligned base such that base plus image_size is
> > > +                       entirely within the 48-bit addressable range
> >
> > This seems to assume text_offset is zero (which is the case today, but this is
> > the first part of booting.txt that assumes that); as a matter of policy are we
> > sure that we'll never use a non-zero offset again? If so, we probably want to
> > mention that in the "header notes" section, or come up with some wording to
> > include it here.
> >
> 
> How about:
> 
> 2MB aligned base such that all image_size bytes
> counted from the start of the image are within
> the 48-bit addressable range
> 
> ?

Sounds good to me, thanks!

Mark.