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Date:	Tue, 10 Nov 2009 10:53:33 -0800
From:	"H. Peter Anvin" <>
To:	Kees Cook <>
CC:	Arjan van de Ven <>,
	Thomas Gleixner <>,
	Ingo Molnar <>,,
	Pekka Enberg <>,
	Jan Beulich <>,
	Vegard Nossum <>,
	Yinghai Lu <>,
	Jeremy Fitzhardinge <>,
Subject: Re: [PATCH v4] [x86] detect and report lack of NX protections

On 11/10/2009 09:46 AM, Kees Cook wrote:
> The kernel as-is does not set nx_enabled for 64-bit, so this message is
> skipped completely:
>         if (nx_enabled)
>                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
> The only time this printk is shown is on 32-bit with PAE (with NX).
> There is no "else" currently.

The structure you have is:

	if (nx_enabled)
	else if (cpu_has_pae)

The test for cpu_has_pae is unconditional (you only #ifdef the message)
-- in fact, this should cause a compile-time error on 64 bits:

#undef  cpu_has_pae
#define cpu_has_pae             ___BUG___

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