[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1203060760.30010.29.camel@caritas-dev.intel.com>
Date: Fri, 15 Feb 2008 15:32:40 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: Andi Kleen <andi@...stfloor.org>, torvalds@...l.org,
tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix left over EFI cache mapping problems
On Fri, 2008-02-15 at 08:08 +0100, Ingo Molnar wrote:
> * Huang, Ying <ying.huang@...el.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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists