Message-ID: <4374D99C.1080006@zytor.com>
Date: Fri, 11 Nov 2005 09:49:16 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Pavel Machek <pavel@ucw.cz>
CC: Zachary Amsden <zach@vmware.com>, Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Zwane Mwaikambo <zwane@arm.linux.org.uk>,
       Pratap Subrahmanyam <pratap@vmware.com>,
       Christopher Li <chrisl@vmware.com>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 1/10] Cr4 is valid on some 486s
References: <200511100032.jAA0WgUq027712@zach-dev.vmware.com> <20051111103605.GC27805@elf.ucw.cz>
In-Reply-To: <20051111103605.GC27805@elf.ucw.cz>
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Pavel Machek wrote:
> Hi!
> 
> 
>>So some 486 processors do have CR4 register.  Allow them to present it in
>>register dumps by using the old fault technique rather than testing processor
>>family.
> 
> 
> I thought Andi commented this as "way too risky", for little
> good. Nested exceptions are evil.
> 									Pavel

I think the 486's that have CR4 are the same that have CPUID, and thus 
can be tested for by the presence of the ID flag.

	-hpa
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