From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org ([103.22.144.67]:51537 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755227AbcETKKf (ORCPT ); Fri, 20 May 2016 06:10:35 -0400 Message-ID: <1463739032.23394.8.camel@ellerman.id.au> Subject: Re: [kernel-hardening] [PATCH v8 2/4] GCC plugin infrastructure From: Michael Ellerman Date: Fri, 20 May 2016 20:10:32 +1000 In-Reply-To: <573D782D.10392.75A275C@pageexec.freemail.hu> References: <20160513015456.01415979f20a68eb7d2d9290@gmail.com> , <20160518123327.9018f73af78a47b4456b2027@gmail.com> , <1463638931.10451.10.camel@ellerman.id.au> <573D782D.10392.75A275C@pageexec.freemail.hu> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: pageexec@freemail.hu, Emese Revfy , kernel-hardening@lists.openwall.com Cc: Andrew Donnellan , linux-kbuild@vger.kernel.org, spender@grsecurity.net, mmarek@suse.com, keescook@chromium.org, linux@rasmusvillemoes.dk, fengguang.wu@intel.com, dvyukov@google.com, linux-kernel@vger.kernel.org, david.brown@linaro.org, yamada.masahiro@socionext.com, linuxppc-dev , Daniel Axtens On Thu, 2016-05-19 at 10:24 +0200, PaX Team wrote: > On 19 May 2016 at 16:22, Michael Ellerman wrote: > > On Wed, 2016-05-18 at 12:33 +0200, Emese Revfy wrote: > > > Did you test the plugins with all gcc versions (4.5-6)? > > > > What's the concern about gcc versions? Just not breaking the build on old > > compilers? > > the earlier plugin capable gcc versions used to install gcc headers in a somewhat > ad-hoc manner resulting in compile time breakage for plugins and since some of > those potentially missing headers are target specific, each target arch should > be verified before enabling plugin support on them. things have much improved with > gcc 5 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61176) though there's still > an occasional missing header but with wider use of plugins they will hopefully be > discovered earlier now. OK thanks. > perhaps linux-arch should be cc'ed on the plugin infrastructure > so that arch maintainers are aware of this? linux-arch is still fairly high traffic, so it's no guarantee arch maintainers will see it, but it's probably worth a try. > > I'm pretty sure powerpc big endian still builds with gcc 4.4. > > > > However if Andrew's only tested on little endian, then that select should be > > guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9. > > i guess that's part of the target tuple so in general arch maintainers should test > the target tuples used on their arch with all the supported gcc versions (speaking > of CC, not HOSTCC/HOSTCXX). Yeah. I think we'll probably enable it gradually as folks get time to test it. ie. ppc64le first, then ppc64 (BE), and then 32-bit if someone is interested. cheers