linux-kernel - Re: [PATCH 1/2] x86: mce init optimization and signedness fixup

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Message-ID: <alpine.LFD.0.9999.0710111844000.15917@localhost.localdomain>
Date:	Thu, 11 Oct 2007 18:50:12 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Christoph Egger <Christoph.Egger@....com>
cc:	Joerg Roedel <joerg.roedel@....com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] x86: mce init optimization and signedness fixup

On Thu, 11 Oct 2007, Christoph Egger wrote:
> On Thursday 11 October 2007 16:55:36 Thomas Gleixner wrote:
> > > > > +
> > > > > +	if (!cpu_has(c, X86_FEATURE_MCA) || !cpu_has(c, X86_FEATURE_MCE)) {
> > > > > +		printk(KERN_INFO "CPU%i: No machine check support available\n",
> > > > > +			smp_processor_id());
> > > > > +		return;
> > > >
> > > > This breaks winchip MCE support.
> > >
> > > First, what is a winchip? It sounds to be something windows specific. ;)
> > > Second, can you explain in which way MCE support gets broken, please?
> >
> > First, winchip is the code name of Centaurs early x86 cpus.
> >
> > Second, those beasts do not have FEATURE_MCA, but they have FEATURE_MCE,
> > so they support the fatal exception, but not the non fatal check.
> 
> So when I change the above code snippet to:
> 
> +	if (!cpu_has(c, X86_FEATURE_MCE)) {
> +		printk(KERN_INFO "CPU%i: No machine check support available\n",
> +			smp_processor_id());
> +		return;
> 
> Would this make the whole patch acceptable then?

Yeah, but then we can clean up the extra checks for _MCE in the various 
cpu type init functions as well.

	tglx
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