Messages in this thread | | | Subject | Re: [PATCH v3] x86, efi: Calling __pa() with an ioremap'd address is invalid | From | Matt Fleming <> | Date | Fri, 11 Nov 2011 13:12:12 +0000 |
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On Fri, 2011-11-11 at 09:02 +0800, huang ying wrote: > On Tue, Nov 8, 2011 at 4:23 AM, Matthew Garrett <mjg59@srcf.ucam.org> wrote: > > On Mon, Nov 07, 2011 at 03:34:48PM +0000, Matt Fleming wrote: > > > >> After the feedback from v1 I tried to unify the efi_ioremap() > >> implementations but ran into the issue detailed in the RH bug report > >> in the changelog. Unless we teach the x86 setup code that > >> EFI_RUNTIME_SERVICES_DATA regions should be part of the direct kernel > >> mapping table (even though they're marked as E820_RESERVED) I think > >> this patch makes the most sense. > > > > Honestly it seems like there may well be an argument for that. We're > > talking about executable code that the kernel will be calling - it seems > > theoretically neater for it to be added to the direct mapping. We're > > just heavily constrained by our collapsing of the EFI memory map onto > > the rather less fine-grained E820 one and the lack of any obvious way to > > extend that in an OS-specific manner. I guess we could expect the > > bootloader to conform to the standard and then re-walk the EFI memory > > map ourselves to fix things up, but eww... > > Sorry for late. > > Why ioremap_cache() can not work for some EFI_RUNTIME_SERVICES_DATA region?
It looks like ioremap_cache() maps the region with the NX bit set.
-- Matt Fleming, Intel Open Source Technology Center
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