Re: [PATCH] x86: Construct 32 bit boot time page tables in native format.

Pavel Machek
2008-01-25T00:20:52Z

On Thu 2008-01-24 15:51:24, H. Peter Anvin wrote:
> Jeremy Fitzhardinge wrote:
>> H. Peter Anvin wrote:
>>> While we're mucking around in this area, there is another thing which we
>>> should eventually get around to fixing:
>>>
>>> we need a set of page tables with an identity mapping as well as the
>>> kernel mapping, for trampolining (during startup, but also during things
>>> like ACPI suspend/resume.) Right now, we let those be the swapper page
>>> tables, but that's probably not really a good idea, since it can hide
>>> bugs.
>>
>> So you're suggesting a second system pagetable which has a P=V alias as
>> well as the normal kernel mapping, used only when we actually need that
>> alias? Sounds simple enough to arrange.
>>
>
> I just looked at the ACPI suspend code, and it looks like it hacks its own
> identity map at runtime. Pavel, am I reading that code right?

Yes, I think so, I believe we do it on both 32 and 64 bit now.

(It is early here. And I almost got the .c wakeup code to work... it
already sets the mode).
Pavel
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