From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from proxy.dresearch.de ([87.193.137.100] helo=mail.dresearch.de) by linuxtogo.org with esmtp (Exim 4.69) (envelope-from ) id 1OBjnG-0001Ss-0R for openembedded-devel@lists.openembedded.org; Tue, 11 May 2010 09:22:21 +0200 Received: from exchange.intern.dresearch.de (unknown [192.168.32.16]) by mail.dresearch.de (Postfix) with ESMTP id 333B9491282 for ; Tue, 11 May 2010 09:18:27 +0200 (CEST) Received: from bfg9000.intern.dresearch.de ([10.32.10.1]) by exchange.intern.dresearch.de with Microsoft SMTPSVC(6.0.3790.4675); Tue, 11 May 2010 09:19:44 +0200 Message-ID: <4BE9050B.6010103@dresearch.de> Date: Tue, 11 May 2010 09:19:39 +0200 From: Thilo Fromm User-Agent: Thunderbird 2.0.0.24 (X11/20100317) MIME-Version: 1.0 To: openembedded-devel@lists.openembedded.org References: <4BE13C20.1010902@dresearch.de> <4BE81DE7.90609@dresearch.de> <1273510550.22943.298.camel@trini-m4400> In-Reply-To: <1273510550.22943.298.camel@trini-m4400> X-OriginalArrivalTime: 11 May 2010 07:19:44.0402 (UTC) FILETIME=[5475BF20:01CAF0DA] X-SA-Exim-Connect-IP: 87.193.137.100 X-SA-Exim-Mail-From: t.fromm@DResearch.de X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on discovery X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00 autolearn=ham version=3.2.5 X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:20:07 +0000) X-SA-Exim-Scanned: Yes (on linuxtogo.org) Subject: Re: Kernel Headers Quality Issue X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 May 2010 07:22:22 -0000 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hello, Tom, >> this is a somewhat cumulated response - I'd like to address some of the >> things mentioned at different points in the discussion in one place. >> Please forgive me should I misquote things. >> >> Graeme Gregory in <20100505094242.GF2444@xora-desktop.xora.org.uk>: >> >> [Steffen Sledz] >> > > It seem's not to be possible to use DEFAULT_PREFERENCE_hipox in the >> > > linux-libc-headers recipes. So what's the right way to handle this? >> > > Something like PREFERRED_VERSION_linux-libc-headers_hipox = "2.6.24" >> > > in angstrom-2008.1.conf? >> > >> [Graeme Gregory] >> > I thought glibc was supposed to gracefully fall back on missing >> > syscalls? >> >> Glibc is compiled against 2.6.31 headers, which is one of our main >> issues here. It only ever *runs* with a 2.6.24 kernel on the target >> system, though. So it cannot know about missing syscalls until runtime. > > So, I think some of the confusion here stems from confusion about (and I > don't know the right answer off-hand) how glibc handles the > --with-kernel=VERSION stuff. What is "--with-kernel"? Glibc offers a compile time configuration parameter "--enable-kernel", which enables/disables *backwards support* library compatibility support for *legacy kernel interfaces*. E.g. if you --enable-kernel=2.2.14, you should be able to compile ancient user space applications which make use of obsolete kernel 2.2.14 functionality against the resulting glibc. This makes systems running *very recent kernels* provide legacy interfaces of much older kernels via the C library. Which is the exact opposite of our situation. The release notes on glibc 2.2.4, which introduced this option, are quite educating (it's Ulrich Drepper writing, so be prepared): (about halfway through the page). But maybe there is a "--with-kernel" around which does the opposite to "--enable-kernel"? Regards, Thilo -- Dipl.-Ing (FH) Thilo Fromm, MSc., Embedded Systems Developer DResearch Digital Media Systems GmbH Otto-Schmirgal-Str. 3, D-10319 Berlin, Germany Amtsgericht: Berlin Charlottenburg, HRB:54412 Tel: +49 (30) 515 932 228 mailto:t.fromm@dresearch.de Fax: +49 (30) 515 932 77 http://www.dresearch.de