Date: Wed, 5 Feb 2014 20:55:06 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vince@deater.net>
Cc: junk@eslaf.co.uk, alan@lxorguk.ukuu.org.uk, Ingo Molnar <mingo@kernel.org>,
        Stephane Eranian <eranian@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf,x86,p6: Add userspace RDPMC quirk for P6
Message-ID: <20140205195506.GN2936@laptop.programming.kicks-ass.net>
References: <20140205102718.GF3229@twins.programming.kicks-ass.net>
 <alpine.DEB.2.02.1402051415190.16225@pianoman.cluster.toy>
 <20140205192012.GL2936@laptop.programming.kicks-ass.net>
 <alpine.DEB.2.02.1402051427210.16596@pianoman.cluster.toy>
 <alpine.DEB.2.02.1402051435540.16859@pianoman.cluster.toy>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.02.1402051435540.16859@pianoman.cluster.toy>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org

On Wed, Feb 05, 2014 at 02:37:29PM -0500, Vince Weaver wrote:
> On Wed, 5 Feb 2014, Vince Weaver wrote:
> 
> > Has someone actually hit this bug?  People used PAPI/perfctr on these 
> > machines for years, and it uses rdpmc by default so I would think it would 
> > show up if it were an issue.  I should check the perfctr code to see if it 
> > had some sort of check.
> 
> I can verify the perfctr code does have a case for PPRO errata 26, but it 
> only disables things on pentium pros with stepping less than 9.

The doc said 0xB1, right? Should we keep it at that? Its not like
there's a lot of PPro machines left out there, so better safe than
sorry.

> It also disables rdpmc on original Pentiums due to errata 74 but I don't 
> think we have to worry about that one.

We don't have a Family 5 driver, so no.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/