Messages in this thread | | | Date | Wed, 30 Sep 2015 10:33:39 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 2/2] arm64/efi: Don't pad between EFI_MEMORY_RUNTIME regions |
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On Tue, Sep 29, 2015 at 05:56:07PM -0700, H. Peter Anvin wrote: > On 09/29/2015 07:36 AM, Matt Fleming wrote: > > > > That's a pretty good summary for x86. I think specifically the reason > > we map the EFI memmap entries "backwards" (entry N has higher VA than > > entry N+1) is because the code was easier to write that way, but > > you'll know better than me ;-) > > > > There were two reasons: > > 1. The code was easier to write. > 2. Windows did it that way. > > Windows apparently broke and was changed due to this feature, too.
So can we do the 1:1 thing again?
I mean, we do create a special pagetable for EFI anyway, we can put in there whatever we want.
I know, some apple boxes reportedly fail when 1:1 mapping is in use but we can do the VA mapping as a workaround for them. I.e., have the 1:1 mapping be the default.
Apparently, there's not a single OS or tool which is used by fw writers to test their brain dumplings. Windoze breakage case-in-point.
Because if there were, we'd simply do what that OS/tool does and be done with it.
What really makes me climb the walls is when half-cooked, untested fw hits the wild and we have to support it indefinitely.
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply.
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