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Subject: Re: [git pull] x86 fixes
From: Harvey Harrison <harvey.harrison@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       "H. Peter Anvin" <hpa@zytor.com>,
       Andrew Morton <akpm@linux-foundation.org>
In-Reply-To: <20080327210122.GA22823@elte.hu>
References: <20080327200309.GA18550@elte.hu>
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Date: Thu, 27 Mar 2008 14:08:53 -0700
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>  arch/x86/mm/fault.c |   11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> Index: linux-x86.q/arch/x86/mm/fault.c
> ===================================================================
> --- linux-x86.q.orig/arch/x86/mm/fault.c
> +++ linux-x86.q/arch/x86/mm/fault.c
> @@ -103,13 +103,10 @@ static int is_prefetch(struct pt_regs *r
>  	int prefetch = 0;
>  	unsigned char *max_instr;
>  
> -#ifdef CONFIG_X86_32
> -	/* Catch an obscure case of prefetch inside an NX page: */
> -	if ((__supported_pte_mask & _PAGE_NX) && (error_code & 16))
> -		return 0;
> -#endif
> -
> -	/* If it was a exec fault on NX page, ignore */
> +	/*
> +	 * If it was a exec (instruction fetch) fault on NX page, then
> +	 * do not ignore the fault:
> +	 */

How about:
If it was an exec (instruction fetch) fault, it cannot be a 		prefetch
fault.

>  	if (error_code & PF_INSTR)
>  		return 0;
>  
> 

Cheers,

Harvey