Messages in this thread | | | Subject | Re: [PATCH] Fix left over EFI cache mapping problems | From | "Huang, Ying" <> | Date | Fri, 15 Feb 2008 15:32:40 +0800 |
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On Fri, 2008-02-15 at 08:08 +0100, Ingo Molnar wrote: > * Huang, Ying <ying.huang@intel.com> wrote: > > > On Thu, 2008-02-14 at 17:12 +0100, Ingo Molnar wrote: > > > this is indeed a bug (we change the attributes for a larger area than > > > needed), but your fix is unclean. Find below a cleaner solution. > > > > > > Ying, if you agree with this fix could you please test and ACK it before > > > we push it to Linus? (this fix is also in the latest x86.git#mm) > > > > I think the patch following may be better, because it is possible that > > the EFI_PAGE_SHIFT and PAGE_SHIFT are different. > > right now, EFI page size is 4096: > > include/linux/efi.h:#define EFI_PAGE_SHIFT 12 > > i doubt we'll ever change PAGE_SIZE on x86 - ia64's variable lowlevel > pagesizes are not particularly useful IMO. I think we'll at most have > some generic kernel feature that allows a larger PAGE_CACHE_SHIFT - but > on the lowlevel MMU level we'll always stay at 4K. > > and i doubt EFI_PAGE_SHIFT would want to (ever) go away from 12 either.
Yes. I think so too.
> So perhaps, at least as far as arch/x86/kernel/efi*.c files go, it would > be cleaner to just replace EFI_PAGE_SHIFT with PAGE_SHIFT and > EFI_PAGE_SIZE with PAGE_SIZE?
Maybe. On x86, the only usage of EFI memory map (and EFI_PAGE_SHIFT/EFI_PAGE_SIZE) is to map the EFI runtime memory area. So I think either dealing with potential difference now or doing it in the future when necessary is easy.
Best Regards, Huang Ying
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