From owner-freebsd-hackers@FreeBSD.ORG Wed Aug 6 16:26:56 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id AF2CEF40 for ; Wed, 6 Aug 2014 16:26:56 +0000 (UTC) Received: from mail-wg0-f45.google.com (mail-wg0-f45.google.com [74.125.82.45]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 44FA623F0 for ; Wed, 6 Aug 2014 16:26:55 +0000 (UTC) Received: by mail-wg0-f45.google.com with SMTP id x12so2873111wgg.4 for ; Wed, 06 Aug 2014 09:26:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; bh=+78RaMKm3sI1Tu3gE0eoCGtdD+2BFNmewrvpZ49kQAw=; b=C2d/x8mrm076Ya2miqySqW2/d53npn95C+ePh7XrXSyAdX7287c269leCzNnuXyggw pEzjQCthXUW+EOSmV3roj4Z1gfoOGmyYl7YggABoKFkc02Y1/yTSSCukUV1r/X/WhBlK hB0I+LAbXp8wR3Ixao3mijFvFYzuP9fKfJ1zm4OMCoxW3B+7WtSfsArRTszUSG7czvFD ORlZ4tjSILfOpq6tOKA+3z1nEH4iiRbYrj4aJEP/qIPWZ1Mv19ZZOxYdT79VrxQ7yv+0 ETNvpfWHuHjyRcJxHIhwLVxpv3whFmzS7QUg2tXoQ4V8VjwyUfCi6sd0sN/A08E580GD cLrA== X-Gm-Message-State: ALoCoQmsWfDXAnYvvzRLEQWUESs/4DP5WEG2sCMxj79vcA3PrnM3SPv9qaceS2dG+dBrj2xRlOUr X-Received: by 10.194.222.230 with SMTP id qp6mr17383204wjc.23.1407341974121; Wed, 06 Aug 2014 09:19:34 -0700 (PDT) Received: from localhost (054142ff.skybroadband.com. [5.65.66.255]) by mx.google.com with ESMTPSA id lh15sm7549333wic.10.2014.08.06.09.19.32 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Aug 2014 09:19:33 -0700 (PDT) Date: Wed, 6 Aug 2014 17:19:32 +0100 From: Matt Fleming To: Eric van Gyzen Subject: Re: Sanity Check: Bogus(?) General Protection Fault Message-ID: <20140806161932.GG15082@console-pimps.org> References: <53E237B6.4040703@vangyzen.net> <20140806144833.GE15082@console-pimps.org> <53E24FF0.7030305@vangyzen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53E24FF0.7030305@vangyzen.net> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Aug 2014 16:26:56 -0000 On Wed, 06 Aug, at 11:55:28AM, Eric van Gyzen wrote: > > Thanks, Matt. That has always been my understanding (and I just found > the docs to confirm). I doubted myself because the problem is now even > more bizarre. The mov before the faulting instruction apparently didn't > complete. %r11 is still an old value, not 0x....f7a8. The mov to %r11 isn't an immediate move, it's a memory read. So %r11 will contain the *contents* of 0xffffffff809bf7a, not the address itself (note the missing '$' as in the shr instruction above it). -- Matt Fleming, Intel Open Source Technology Center