From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <andi@firstfloor.org>,
tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Folding _PAGE_PWT into _PAGE_PCD (was Re: unify pagetable accessors patch causes double fault II)
Date: Tue, 15 Jan 2008 09:16:50 -0800 [thread overview]
Message-ID: <478CEA82.9010606@goop.org> (raw)
In-Reply-To: <20080115135317.GA13493@elte.hu>
Ingo Molnar wrote:
> -#define _PAGE_PRESENT (_AC(1, UL)<<_PAGE_BIT_PRESENT)
> -#define _PAGE_RW (_AC(1, UL)<<_PAGE_BIT_RW)
> -#define _PAGE_USER (_AC(1, UL)<<_PAGE_BIT_USER)
> -#define _PAGE_PWT (_AC(1, UL)<<_PAGE_BIT_PWT)
> -#define _PAGE_PCD ((_AC(1, UL)<<_PAGE_BIT_PCD) | _PAGE_PWT)
>
BTW, I just noticed that _PAGE_PWT has been folded into _PAGE_PCD. This
seems like a really bad idea to me, since it breaks the rule that
_PAGE_X == 1 << _PAGE_BIT_X. I can't think of a specific place where
this would cause problems, but this kind of non-uniformity always ends
up biting someone in the arse.
I think having a specific _PAGE_NOCACHE which combines these bits is a
better approach.
J
next prev parent reply other threads:[~2008-01-15 17:17 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080114094814.GA28300@basil.nowhere.org>
2008-01-14 12:56 ` unify pagetable accessors patch causes double fault II Andi Kleen
2008-01-14 13:06 ` Ingo Molnar
2008-01-14 13:58 ` Andi Kleen
2008-01-14 16:44 ` Jeremy Fitzhardinge
2008-01-14 16:56 ` Ingo Molnar
2008-01-14 17:08 ` Andi Kleen
2008-01-14 17:18 ` unify pagetable accessors patch causes double fault III Andi Kleen
2008-01-14 19:00 ` Ingo Molnar
2008-01-14 19:54 ` Jeremy Fitzhardinge
2008-01-14 20:15 ` Andi Kleen
2008-01-14 19:52 ` unify pagetable accessors patch causes double fault II Jeremy Fitzhardinge
2008-01-14 22:03 ` Jeremy Fitzhardinge
2008-01-14 22:23 ` Andi Kleen
2008-01-14 22:46 ` Jeremy Fitzhardinge
2008-01-15 1:05 ` Andi Kleen
2008-01-15 1:32 ` Jeremy Fitzhardinge
2008-01-15 1:38 ` Andi Kleen
2008-01-15 21:03 ` [patch] x86: lfence fix Ingo Molnar
2008-01-16 0:44 ` Andi Kleen
2008-01-15 12:55 ` unify pagetable accessors patch causes double fault II Ingo Molnar
2008-01-15 16:53 ` Andi Kleen
2008-01-15 13:53 ` Ingo Molnar
2008-01-15 17:16 ` Jeremy Fitzhardinge [this message]
2008-01-15 17:23 ` Folding _PAGE_PWT into _PAGE_PCD (was Re: unify pagetable accessors patch causes double fault II) Andi Kleen
2008-01-15 17:32 ` Jeremy Fitzhardinge
2008-01-15 17:39 ` Andi Kleen
2008-01-15 20:30 ` Venki Pallipadi
2008-01-15 20:45 ` Jeremy Fitzhardinge
2008-01-15 17:36 ` unify pagetable accessors patch causes double fault II Andi Kleen
2008-01-15 19:43 ` Jeremy Fitzhardinge
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