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Date: Sun, 17 Aug 2008 23:34:50 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Andi Kleen <andi@firstfloor.org>
CC: "Maciej W. Rozycki" <macro@linux-mips.org>, David Fries <david@fries.net>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix i486 suspend to disk CR4 oops
References: <20080818040340.GB17528@spacedout.fries.net>	<Pine.LNX.4.55.0808180510480.26857@cliff.in.clinika.pl>	<48A8FC21.9060908@zytor.com> <87skt2270c.fsf@basil.nowhere.org>
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Andi Kleen wrote:
>>>
>> The other alternative is to probe for the CPUID instruction (via
>> EFLAGS.ID) -- CR4 is present if and only if CPUID exists.
> 
> Can be already checked for with boot_cpu_data.extended_cpuid_level.
> 

I believe you mean just plain cpuid_level (which is set to -1 if CPUID 
doesn't exist.)  extended_cpuid_level is only defined on x86-64, but all 
x86-64 CPUs have CR4.

	-hpa