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On Sat, 2012-12-15 at 15:37 -0800, Linus Torvalds wrote:
> And why do we have to call the get-time calls so early? Couldn't we
> move them later and avoid all the crazy "let's create silly magical
> page tables just for the idiotic EFI problems".

Unfortunately not, because this patch series fixes the case where some
ASUS EFI machines ignore parts of the memory map that we invalidate with
SetVirtualAddressMap() - so the firmware is accessing mappings for
devices after we explicitly tell it they're no longer valid.

It's possible to trigger this broken behaviour at whatever point we
interact with the firmware.