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Subject: Re: [PATCH] x86: make nx_enabled conditional on CONFIG_X86_PAE
From: Harvey Harrison <harvey.harrison@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ian Campbell <ijc@hellion.org.uk>,
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       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@redhat.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>
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Date: Tue, 22 Jan 2008 13:07:59 -0800
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On Tue, 2008-01-22 at 13:00 -0800, Harvey Harrison wrote:
> nx_enabled can only be set to non-zero when CONFIG_X86_PAE is
> set.  The only use not currently inside a CONFIG_X86_PAE block
> is the definition, the declaration and a conditional unlikely
> test in fault_32.c (is_prefetch).
> 
> When !CONFIG_X86_PAE, is_prefetch always returns 0 immediately
> as nx_enabled is always 0.
> 
> When CONFIG_X86_PAE, the test is preserved, but the test against
> the cpu model and stepping is deleted, this may not be correct.
> 
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> ---

Sorry, I missed the usage in kernel/acpi/wakeup_32.S, that's the only
other user.  I don't know that code well enough to comment on the usage
there, but if anybody knows if that could be conditionalized, please
advise.


Harvey