Re: [PATCH] Remove warning in efi_enter_virtual_mode

From: H. Peter Anvin
Date: Thu Apr 18 2013 - 12:38:36 EST


On 04/18/2013 09:33 AM, Josh Triplett wrote:
> On Thu, Apr 18, 2013 at 12:00:26PM +0100, Matt Fleming wrote:
>>> No, no - we *don't* have a BGRT object at all.
>>>
>>> We have a completely clean memory map - but the BGRT code is causing the
>>> is_ram() failure.
>>
>> You assume that mapping of the Boot Services regions is done purely for
>> the benefit of pulling out the bgrt image - it's not, see the above
>> commit log - and I assumed that you had an ACPI bgrt pointer in your
>> memory map, but you don't.
>>
>> Darren, Josh, have you ever seen an i386 machine with a bgrt pointer? If
>> not, and given that we've never seen an i386 firmware that requires the
>> above workaround from Matthew, combined with the fact that there are so
>> few i386 implementations out there, I'm inclined to apply the patch
>> below, because anything else is a lot more work. We can address this
>> properly if we ever start seeing i386 machines with bgrt pointers that
>> reference highmem.
>
> The machine I developed the BGRT changes on kept the image below the 4G
> mark, inside one of the memory regions reclaimable via
> ExitBootServices().
>

Well, highmem is >= ~896M. Do you have a machine with BGRT over the
highmem mark?

-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/