linux-kernel - Re: [PATCH 4 of 4] x86: mask NX from pte

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Message-ID: <Pine.LNX.4.64.0801181350090.27929@blonde.site>
Date:	Fri, 18 Jan 2008 13:52:33 +0000 (GMT)
From:	Hugh Dickins <hugh@...itas.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
cc:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>,
	Andi Kleen <ak@...e.de>,
	Glauber de Oliveira Costa <glommer@...il.com>,
	Jan Beulich <jbeulich@...ell.com>
Subject: Re: [PATCH 4 of 4] x86: mask NX from pte_pfn

On Tue, 15 Jan 2008, Jeremy Fitzhardinge wrote:
> In 32-bit PAE, mask NX from pte_pfn, since it isn't part of the PFN.
> This code is due for unification anyway, but this fixes a latent bug.
> 
> Signed-off-by: Jeremy Fitzhardinge <jeremy@...source.com>
> 
> ---
>  include/asm-x86/pgtable-3level.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/asm-x86/pgtable-3level.h b/include/asm-x86/pgtable-3level.h
> --- a/include/asm-x86/pgtable-3level.h
> +++ b/include/asm-x86/pgtable-3level.h
> @@ -139,7 +139,7 @@ static inline int pte_none(pte_t pte)
>  
>  static inline unsigned long pte_pfn(pte_t pte)
>  {
> -	return pte_val(pte) >> PAGE_SHIFT;
> +	return (pte_val(pte) >> PAGE_SHIFT) & ~_PAGE_NX;
>  }
>  
>  /*

Shouldn't that be

	return (pte_val(pte) & ~_PAGE_NX) >> PAGE_SHIFT;

? Hugh
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