Re: [PATCH v2] arm64/efi: prefer AllocatePages() over efi_low_alloc() for vmlinux

[Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>]

On Tue, 28 Jul, at 11:24:23PM, Ard Biesheuvel wrote:
> 
> This workaround fixes another issue as well: the arm64 kernel needs to
> be loaded 512 KB above a 2MB aligned boundary, and using
> efi_low_alloc() as we do loses (2 MB - 512 KB) at the bottom if part
> of that 512 KB is occupied, since efi_low_alloc() is not aware of the
> fact that the first 512 KB will remain unused.
> 
> What would be most helpful is if efi_low_alloc() could take an offset
> param in addition to the alignment, i.e., alignment == 2MB and offset
> == 512 KB. The offset would default to 0, reverting to the original
> behavior.
> 
> If you'd be ok with such a change, I can propose it instead, and wire
> it up into this function.

It's probably because it's late but I'm having trouble thinking this
change through fully.

If it's not too much work, sure, please go ahead and propose a patch,
even the untested, uncompiled "this is what I'm thinking" type.

-- 
Matt Fleming, Intel Open Source Technology Center