Re: [PATCH] Remove warning in efi_enter_virtual_mode

From: Darren Hart
Date: Thu Apr 18 2013 - 16:18:16 EST


On 04/18/2013 01:13 PM, H. Peter Anvin wrote:
> On 04/18/2013 01:11 PM, Darren Hart wrote:
>>>
>>> I would expect that if there are any 32-bit UEFI systems that ship with
>>> BGRT support (and Darren makes it sound like that's a possibility),
>>> there's a realistic chance of the BGRT ending up allocated above the
>>> highmem barrier.
>>
>> I can certainly ensure we sit below that barrier on the MinnowBoard. We
>> can also speak with the Intel UEFI firmware development teams to see
>> about making that a requirement. I don't know if we'll be successful,
>> but Matt, Peter, and I have recently coaxed some changes of that nature in.
>>
>
> No, that is the wrong approach. The HIGHMEM barrier is a Linux kernel
> construct and isn't even guaranteed to be the same from one boot *of the
> same kernel* to another. The value 896M is merely the default, but it
> can be affected by both compile time and command line options.
>
> -hpa

Ah, well then I've misunderstood the nature of the problem a bit. Will
have to spend some time understanding this better.

--
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel
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