Messages in this thread | | | Date | Mon, 7 Nov 2011 20:23:24 +0000 | From | Matthew Garrett <> | Subject | Re: [PATCH v3] x86, efi: Calling __pa() with an ioremap'd address is invalid |
| |
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...
-- Matthew Garrett | mjg59@srcf.ucam.org
| |