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

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Date:	Thu, 11 Oct 2007 17:03:34 +0200
From:	"Christoph Egger" <Christoph.Egger@....com>
To:	"Thomas Gleixner" <tglx@...utronix.de>
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 Thursday 11 October 2007 16:55:36 Thomas Gleixner wrote:
> On Thu, 11 Oct 2007, Christoph Egger wrote:
> > On Thursday 11 October 2007 15:51:49 Thomas Gleixner wrote:
> > > On Thu, 11 Oct 2007, Joerg Roedel wrote:
> > > > MCG_CAP never reports a negative count of available error-reporting
> > > > banks. Therefore, make nr_mce_banks unsigned.
> > > > Check for MCA/MCE feature bits as early as possible.
> > > >
> > > > +
> > > > +	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?



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