From owner-freebsd-amd64@freebsd.org  Wed Feb 10 21:57:56 2016
Return-Path: <owner-freebsd-amd64@freebsd.org>
Delivered-To: freebsd-amd64@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 9451BAA5755
 for <freebsd-amd64@mailman.ysv.freebsd.org>;
 Wed, 10 Feb 2016 21:57:56 +0000 (UTC)
 (envelope-from bugzilla-noreply@freebsd.org)
Received: from kenobi.freebsd.org (kenobi.freebsd.org
 [IPv6:2001:1900:2254:206a::16:76])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 878471843
 for <freebsd-amd64@FreeBSD.org>; Wed, 10 Feb 2016 21:57:56 +0000 (UTC)
 (envelope-from bugzilla-noreply@freebsd.org)
Received: from bugs.freebsd.org ([127.0.1.118])
 by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id u1ALvuoX039279
 for <freebsd-amd64@FreeBSD.org>; Wed, 10 Feb 2016 21:57:56 GMT
 (envelope-from bugzilla-noreply@freebsd.org)
From: bugzilla-noreply@freebsd.org
To: freebsd-amd64@FreeBSD.org
Subject: [Bug 207068] hwpmc wrap around/sign extension
Date: Wed, 10 Feb 2016 21:57:56 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: Base System
X-Bugzilla-Component: kern
X-Bugzilla-Version: 10.2-STABLE
X-Bugzilla-Keywords: hwpmc
X-Bugzilla-Severity: Affects Some People
X-Bugzilla-Who: joss.upton@yahoo.com
X-Bugzilla-Status: New
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: ---
X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-207068-6-oJca4VboNV@https.bugs.freebsd.org/bugzilla/>
In-Reply-To: <bug-207068-6@https.bugs.freebsd.org/bugzilla/>
References: <bug-207068-6@https.bugs.freebsd.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-Mailman-Approved-At: Thu, 11 Feb 2016 00:20:12 +0000
X-BeenThere: freebsd-amd64@freebsd.org
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: Porting FreeBSD to the AMD64 platform <freebsd-amd64.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-amd64>,
 <mailto:freebsd-amd64-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-amd64/>
List-Post: <mailto:freebsd-amd64@freebsd.org>
List-Help: <mailto:freebsd-amd64-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-amd64>,
 <mailto:freebsd-amd64-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 10 Feb 2016 21:57:56 -0000

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D207068

--- Comment #6 from joss.upton@yahoo.com ---
(In reply to joss.upton from comment #5)
Actually, the best test might be to do this:

uint64_t num;

num =3D rdmsr(0xc1);
printf("init: %lx\n", num);
wrmsr(0xc1, 0x80000000);
num =3D rdmsr(0xc1);
printf("after e31: %lx\n", num);

When I do this:

init: 0
after e31: ffff80000000

This behavior is correct according to the Intel manual, but causes issues w=
ith
negative increments if you race it long enough.

--=20
You are receiving this mail because:
You are on the CC list for the bug.=