On Tue, 2015-07-28 at 15:59 +0100, Mark Rutland wrote:

Hi Mark,

As a heads-up, it looks like you missed a space when sending this; Arnd
and Ard got merged into:

"Arnd Bergmann [off-list ref]--cc=Ard Biesheuvel" <
ard.biesheuvel at linaro.org>

I've corrected that for this reply.

Oops. Thanks.

On Tue, Jul 28, 2015 at 03:32:39PM +0100, Mark Salter wrote:

quoted

When booting an arm64 kernel w/initrd using UEFI/grub, use of mem= will 
likely
cut off part or all of the initrd. This leaves it outside the kernel 
linear
map which leads to failure when unpacking. The x86 code has a similar 
need to
relocate an initrd outside of mapped memory in some cases.

The current x86 code uses early_memremap() to copy the original initrd 
from
unmapped to mapped RAM. This patchset creates a generic 
copy_from_early_mem()
utility based on that x86 code and has arm64 use it to relocate the 
initrd
if necessary.

This sounds like a sane idea to me.

quoted

Mark Salter (2):
  mm: add utility for early copy from unmapped ram
  arm64: support initrd outside kernel linear map

 arch/arm64/kernel/setup.c           | 55 
+++++++++++++++++++++++++++++++++++++
 include/asm-generic/early_ioremap.h |  6 ++++
 mm/early_ioremap.c                  | 22 +++++++++++++++
 3 files changed, 83 insertions(+)

Any reason for not moving x86 over to the new generic version?

I have a patch to do that but I'm not sure how to contrive a
testcase to exercise it.