Re: [PATCH v2 08/20] x86, ACPI: Find acpi tables in initrd early from head_32.S/head64.c

H. Peter Anvin
2013-03-10T17:46:12Z

There is no 64-bit flat mode. We use a #PF handler to emulate one by creating page tables on the fly.

Yinghai Lu <yinghai@kernel.org> wrote:

>On Sun, Mar 10, 2013 at 3:25 AM, Pekka Enberg <penberg@kernel.org>
>wrote:
>>
>> What is preventing us from making the 64-bit variant also work in
>flat
>> mode to make the code consistent and not hiding the differences under
>> the rug? What am I missing here?
>
>Boot loader could start kernel from 64bit directly from
>from arch/x86/boot/compressed/head_64.s::startup_64.
>
>initrd can be loaded by 64bit bootloader above 4G.
>
>So we even switch back to 32bit flat mode, we still can not access
>those initrd
>directly.
>
>Thanks
>
>Yinghai

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