Re: [PATCH] x86, boot: Allow 64bit EFI kernel to be loaded above 4G

From: Matt Fleming
Date: Thu Feb 12 2015 - 09:59:51 EST

On Wed, 11 Feb, at 11:29:58AM, Peter Jones wrote:
> From grub's point of view I'm not sure why we'd care - the pages kernel
> and initramfs land in are both from the Boot Services allocator, so if the
> machine doesn't support high addresses, they won't be there.

It's not that some implementations don't "support" higher addresses,
it's that the EFI_FILE_PROTOCOL is buggy and it corrupts the memory when
reading into it; you can allocate it just fine. At least, that's what I
remember from the limited investigation I performed.

But since grub doesn't use EFI_FILE_PROTOCOL, we should be cool.

Matt Fleming, Intel Open Source Technology Center
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