Date: Thu, 27 Mar 2008 21:55:27 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Harvey Harrison <harvey.harrison@gmail.com>
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>
Subject: Re: [git pull] x86 fixes
Message-ID: <20080327205527.GA21912@elte.hu>
References: <20080327200309.GA18550@elte.hu> <alpine.LFD.1.00.0803271325430.14670@woody.linux-foundation.org> <1206650939.24940.43.camel@brick>
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* Harvey Harrison <harvey.harrison@gmail.com> wrote:

> -#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 (error_code & PF_INSTR)
> +	if ((__supported_pte_mask & _PAGE_NX) && (error_code & PF_INSTR))
>  		return 0;

heh, did the exact same cleanup :)

i suspect we would be fine with a simple:

	if (error_code & PF_INSTR)
  		return 0;

because if we get a fault on an instruction fetch then it clearly cannot 
be a prefetch erratum ... The NX condition simply comes from a cautious 
32-bit workaround. (on 64-bit we always have NX - at least on AMD which 
has this erratum.)

and thus the currently pulled code is not incorrect, just ugly and 
nonsensical.

	Ingo
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