Messages in this thread | | | Date | Tue, 29 Oct 2013 10:40:34 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 12/12] EFI: Runtime services virtual mapping |
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On Tue, Oct 29, 2013 at 02:47:20PM +0800, Dave Young wrote: > Boris, could you update the comment? it says below: update that memory > descriptor with the virtual address obtained from ioremap(). > > Logiclly your patch should update it, then my patch update it again > with the case of mapping to fixed address for kexec.
Thanks for catching this, I ended up doing the following:
/* * This function will switch the EFI runtime services to virtual mode. * Essentially, we look through the EFI memmap and map every region that * has the runtime attribute bit set in its memory descriptor into the * ->trampoline_pgd page table using a top-down VA allocation scheme. * * The old method which used to update that memory descriptor with the * virtual address obtained from ioremap() is still supported when the * kernel is booted with efi=old_map on its command line. Same old * method enabled the runtime services to be called without having to * thunk back into physical mode for every invocation. * * The new method does a pagetable switch in a preemption-safe manner * so that we're in a different address space when calling a runtime * function. For function arguments passing we do copy the PGDs of the * kernel page table into ->trampoline_pgd prior to each call. */
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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