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Date: Tue, 1 Feb 2011 09:02:23 +0100
From: Ingo Molnar <mingo@elte.hu>
To: matthieu castet <castet.matthieu@free.fr>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>,
        linux-security-module@vger.kernel.org, Matthias Hopf <mhopf@suse.de>,
        rjw@sisk.pl, Andrew Morton <akpm@linux-foundation.org>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] NX protection for kernel data : fix 32 bits S3 suspend
Message-ID: <20110201080223.GB20372@elte.hu>
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* matthieu castet <castet.matthieu@free.fr> wrote:

>  static inline int is_kernel_text(unsigned long addr)
>  {
> +#if defined(CONFIG_X86_32) && defined(CONFIG_ACPI_SLEEP)
> +	/*
> +	 * We need to make the wakeup trampoline in first 1MB !NX
> +	 */
> +	if (addr >= PAGE_OFFSET && addr <= (PAGE_OFFSET + (1<<20)))
> +		return 1;
> +#endif

That's pretty ugly. Why not use set_memory_x()/set_memory_nx(), and only for the 
trampoline itself? Does the whole 1MB need to be marked X?

Same goes for the Xen fix.

Thanks,

	Ingo