From owner-freebsd-current@FreeBSD.ORG Thu Jun 16 01:06:13 2011 Return-Path: <owner-freebsd-current@FreeBSD.ORG> Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7D072106566B; Thu, 16 Jun 2011 01:06:13 +0000 (UTC) (envelope-from julian@freebsd.org) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) by mx1.freebsd.org (Postfix) with ESMTP id 4DD6B8FC08; Thu, 16 Jun 2011 01:06:12 +0000 (UTC) Received: from julian-mac.elischer.org (home-nat.elischer.org [67.100.89.137]) (authenticated bits=0) by vps1.elischer.org (8.14.4/8.14.4) with ESMTP id p5G169gw072268 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Wed, 15 Jun 2011 18:06:11 -0700 (PDT) (envelope-from julian@freebsd.org) Message-ID: <4DF95709.5000100@freebsd.org> Date: Wed, 15 Jun 2011 18:06:17 -0700 From: Julian Elischer <julian@freebsd.org> User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.4; en-US; rv:1.9.2.17) Gecko/20110414 Thunderbird/3.1.10 MIME-Version: 1.0 To: Scott Long <scottl@samsco.org> References: <20110614161105.GA17306@onelab2.iet.unipi.it> <BANLkTinOq73nGQT88NByuOgH3ByuA=ZLJA@mail.gmail.com> <4A46AC77-BEE5-4401-8896-4E4F1A5304B0@samsco.org> <4DF951E3.7010209@freebsd.org> <FA098515-E1C8-4514-81BA-C361DE248D84@samsco.org> In-Reply-To: <FA098515-E1C8-4514-81BA-C361DE248D84@samsco.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Luigi Rizzo <rizzo@iet.unipi.it>, "K. Macy" <kmacy@freebsd.org>, current@freebsd.org Subject: Re: fast/syscall-free gettimeofday ? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current <freebsd-current.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current> List-Post: <mailto:freebsd-current@freebsd.org> List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=subscribe> X-List-Received-Date: Thu, 16 Jun 2011 01:06:13 -0000 > On Jun 15, 2011, at 6:44 PM, Julian Elischer wrote: >>> If this was to be extended with cached global syscall information like gettimeofday, would we want that to be in a separate page that is marked non-executable? Is there any way to trick the kernel into leaking arbitrary (and thus executable) code? Also, would it matter for jails? Per-process info like getpid would obviously have to be a separate per-process page. >>> >>> Scott >>> >> In the talk about this sort of topic I have seen mention at various times >> of a page per system, a page per jail, a page per process and a page per thread. >> >> I'm not saying we want this all just that I've seen it mentionned.. >> >> The per-thread one is the most intersting to do challenge wise. > I guess that per-thread would be done via a pointer off of the TLS data, or would it be yet another bumping of the stack? It would be interesting to see how expensive it is to go that direction. note that I wasn't volunteering ;-) > Scott > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" > >