From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gate.tarent.de ([212.79.178.249] helo=ugs.tarent.de) by linuxtogo.org with esmtp (Exim 4.69) (envelope-from ) id 1OP9HP-00017s-I8 for openembedded-devel@lists.openembedded.org; Thu, 17 Jun 2010 09:13:00 +0200 Received: from localhost (localhost [127.0.0.1]) by ugs.tarent.de (Postfix) with ESMTP id 19BEA400057E9 for ; Thu, 17 Jun 2010 09:08:21 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by ugs.tarent.de (Postfix) with ESMTP id 119F040019CDE for ; Thu, 17 Jun 2010 09:08:21 +0200 (CEST) X-Virus-Scanned: by amavisd-new-2.6.1 (20080629) (Debian) at tarent.de Received: from ugs.tarent.de ([127.0.0.1]) by localhost (ugs.tarent.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Bnbd6nhosdDF for ; Thu, 17 Jun 2010 09:08:20 +0200 (CEST) Received: from [192.168.4.51] (entw2.tarent.buero [192.168.4.51]) by ugs.tarent.de (Postfix) with ESMTPSA id D0056400057E9 for ; Thu, 17 Jun 2010 09:08:20 +0200 (CEST) Message-ID: <4C19CA2D.4@gmx.net> Date: Thu, 17 Jun 2010 09:09:33 +0200 From: Robert Schuster User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100423 Thunderbird/3.0.4 MIME-Version: 1.0 To: openembedded-devel@lists.openembedded.org References: <4C187CF6.5010401@gmx.net> <20100616090200.5c23b895@xora-desktop.xora.org.uk> <20100616175640.4d7795ff@xora-desktop.xora.org.uk> In-Reply-To: X-Enigmail-Version: 1.0.1 X-SA-Exim-Connect-IP: 212.79.178.249 X-SA-Exim-Mail-From: thebohemian@gmx.net X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on discovery X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,SPF_FAIL autolearn=no 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: [RFC] add ubuntu patch which adds atomic builtin support to gcc 4.3.[3 but also other microversions] 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: Thu, 17 Jun 2010 07:13:45 -0000 X-Groupsio-MsgNum: 20224 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig934A46D75EE532CFA68A52DE" --------------enig934A46D75EE532CFA68A52DE Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, first of all. As Stefan pointed out the change was needed while working for Buglabs on OpenJDK support. So it was decided that the introduction of the mentioned GCC change is handled by Stefan Schmidt now. But I would like to elaborate on the side-effects of the patch. Am 16.06.2010 19:12, schrieb Khem Raj: > > Those applications are working fine and they will keep working fine as > long as you dont recompile them > and you make sure that libgcc is updated then whenever you rebuild an > application that uses the atomic > builtins will start using them until then it should work without using = them. > =20 Yes, already built and shipped applications are not affected at all. It is only that when certain packages are built again with the new GCC, the package's binary will be different although PR (and PV) did not change. The reason is that most configure scripts check for the availability of the GCC intrinsics. If they are found they make use of it, if not they either use a different implementation (libatomic-ops for example) or bring their own (software running on ARM Linux 2.6 can assume that the neccessary kernel helpers exist and make use of them[0]) or silently disable multithread support (that is the case for llvm 2.7). And already compiled software will also not magically pick up the implementation found in libgcc because: 1) it was not there before 2) I am under the impression that at least some of the builtins are actually macros and thus bits of machinecode are copied into each binary using them. However as said. Stefan is now dealing with the issue. He has gotten two patches (one from Ubuntu, another one from the GCC 4.4 stable branch) that we needed to get things going and is most likely checking the effects they have. Regards, Robert [0] - code like this can be found in many projects; search for __kernel_dmb and __kernel_cmpxchg: http://code.google.com/p/nativeclient/source/browse/trunk/src/native_clie= nt/src/include/linux/arm/atomic_ops.h?r=3D857 > Maybe I am missing something it would be helpful if Robert could > explain potential scenarios > where it would break precompiled binaries. I don't see it. > > =20 >> Graeme >> >> _______________________________________________ >> Openembedded-devel mailing list >> Openembedded-devel@lists.openembedded.org >> http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel= >> >> =20 > _______________________________________________ > Openembedded-devel mailing list > Openembedded-devel@lists.openembedded.org > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel > =20 --------------enig934A46D75EE532CFA68A52DE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkwZyjEACgkQG9cfwmwwEtq30QCcCW1NGRB+qjeiyHBmKyOhAMXx kpsAn2rchWYszgZBWsCNvad0FoVe4730 =pNGi -----END PGP SIGNATURE----- --------------enig934A46D75EE532CFA68A52DE--