linux-kernel - Re: [PATCH] video:uvesafb: Fix oops that uvesafb try to execute NX-protected page

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Message-ID: <20120327143243.015ecff6@pyramind.ukuu.org.uk>
Date:	Tue, 27 Mar 2012 14:32:43 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Wang YanQing <udknight@...il.com>
Cc:	FlorianSchandinat@....de, linux-fbdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, spock@...too.org
Subject: Re: [PATCH] video:uvesafb: Fix oops that uvesafb try to execute
 NX-protected page

On Tue, 27 Mar 2012 18:01:36 +0800
Wang YanQing <udknight@...il.com> wrote:

> 
> Ok! I try to check pcibios_enabled first, but get some opposition by Alan Cox,
> but I want to make thing work and fix the oops, so I choice the simple way to
> check the (__supported_pte_mask & _PAGE_NX) instead of to check this variable plus
> pci kernel boot parameter, pci mmconfig works or not, and more, and more. It is not
> the best method, but it works and maybe all will feel happy.

Okay let me ask the obvious question - why is it not the best method ?

Apart from adding a helper in the includes for the arch code of

	static inline is_nx_enabled(void)
	{
		return !!(__supported_pte_mask & _PAGE_NX);
	}

is there anything else it lacks ?

Yes ideally we'd set the relevant ROM areas executable, but for a simple
fix is there anything else that's a problem with it ?

Alan
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