From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [RFC v3 07/13] tables.h: add linker table support Date: Fri, 12 Aug 2016 09:25:07 +0200 Message-ID: <20160812072507.GC12013@nazgul.tnic> References: <1469222687-1600-1-git-send-email-mcgrof@kernel.org> <1469222687-1600-8-git-send-email-mcgrof@kernel.org> <20160729100630.GA27271@nazgul.tnic> <20160808150539.GG3296@wotan.suse.de> <20160809035508.GC11445@nazgul.tnic> <20160812035129.GA3296@wotan.suse.de> <20160812052303.GB12013@nazgul.tnic> <20160812065011.GB3296@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20160812065011.GB3296@wotan.suse.de> Sender: linux-sh-owner@vger.kernel.org To: "Luis R. Rodriguez" Cc: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, linux@arm.linux.org.uk, mhiramat@kernel.org, masami.hiramatsu.pt@hitachi.com, jbaron@akamai.com, heiko.carstens@de.ibm.com, ananth@linux.vnet.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, realmz6@gmail.com, x86@kernel.org, luto@amacapital.net, keescook@chromium.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, rusty@rustcorp.com.au, gnomes@lxorguk.ukuu.org.uk, alan@linux.intel.com, dwmw2@infradead.org, arnd@arndb.de, ming.lei@canonical.com, linux-arch@vger.kernel.org, benh@kernel.crashing.org, ananth@in.ibm.com, pebolle@tiscali.nl, fontana@sharpeleven.org, ciaran.farrell@suse.com, christopher.denicolo@suse.com, david.vrabel@citrix.com, konrad.wilk@oracle.com, mcb30@ipxe.org, jgross@suse.com, andrew.cooper3@citrix.com, andriy.shevchenko@linux.intel.com, paul.gortmaker@windriver.com, xen- List-Id: linux-arch.vger.kernel.org On Fri, Aug 12, 2016 at 08:50:11AM +0200, Luis R. Rodriguez wrote: > On Fri, Aug 12, 2016 at 07:23:03AM +0200, Borislav Petkov wrote: > > On Fri, Aug 12, 2016 at 05:51:29AM +0200, Luis R. Rodriguez wrote: > > > OK I've added CONFIG_BUILD_AVOID_BITROT. > > > > What does that do? > > > Enabling it allows the forced compilation chosen by maintainers. > Otherwise forced compilations with the new special targets are > ignored. Nice. > I've gone with table-obj-y and table-lib-y as we have > to support both lib-y and obj-y respective targets. > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 33e2966dd741..7893e3b8da82 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1895,6 +1895,30 @@ config PROVIDE_OHCI1394_DMA_INIT > > See Documentation/debugging-via-ohci1394.txt for more information. > > +config BUILD_AVOID_BITROT > + bool "Always force building specially annotated" ...annotated targets" > + default y > + help > + If enabled then the the special table-* Makefile targets will always > + be forced to be compiled even if their respective CONFIG_ option has > + been disabled, but its objects will only be linked in if the same > + respective CONFIG_ option has been enabled. This helps avoid code > + bit rot issues, use for these targets should be carefully considred > + by maintainers. You can safely enable this option at the expense of > + increasing compile time slightly. Enabling this option helps avoid s/slightly// :-) > + code bit rot by taking advantage of the facilities provided and > + enabled by using linker tables documented under: > + > + include/linux/tables.h > + > + The special targets supported are: > + > + o table-obj-y > + o table-lib-y > + > + Say Y unless you are a grumpy maintainer and don't trust other > + maintainer's judgements on what code should always get compiled. ... or you're running a tiny-config setup ... or you're an embedded, resource-constrained person ... or you simply don't want to have stuff which is forcibly enabled on you even if you're never going to need it ... I got a million o'those :-) Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.skyhub.de ([78.46.96.112]:52306 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088AbcHLHZu (ORCPT ); Fri, 12 Aug 2016 03:25:50 -0400 Date: Fri, 12 Aug 2016 09:25:07 +0200 From: Borislav Petkov Subject: Re: [RFC v3 07/13] tables.h: add linker table support Message-ID: <20160812072507.GC12013@nazgul.tnic> References: <1469222687-1600-1-git-send-email-mcgrof@kernel.org> <1469222687-1600-8-git-send-email-mcgrof@kernel.org> <20160729100630.GA27271@nazgul.tnic> <20160808150539.GG3296@wotan.suse.de> <20160809035508.GC11445@nazgul.tnic> <20160812035129.GA3296@wotan.suse.de> <20160812052303.GB12013@nazgul.tnic> <20160812065011.GB3296@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20160812065011.GB3296@wotan.suse.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: "Luis R. Rodriguez" Cc: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, linux@arm.linux.org.uk, mhiramat@kernel.org, masami.hiramatsu.pt@hitachi.com, jbaron@akamai.com, heiko.carstens@de.ibm.com, ananth@linux.vnet.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, realmz6@gmail.com, x86@kernel.org, luto@amacapital.net, keescook@chromium.org, torvalds@linux-foundation.org, gregkh@linuxfoundation.org, rusty@rustcorp.com.au, gnomes@lxorguk.ukuu.org.uk, alan@linux.intel.com, dwmw2@infradead.org, arnd@arndb.de, ming.lei@canonical.com, linux-arch@vger.kernel.org, benh@kernel.crashing.org, ananth@in.ibm.com, pebolle@tiscali.nl, fontana@sharpeleven.org, ciaran.farrell@suse.com, christopher.denicolo@suse.com, david.vrabel@citrix.com, konrad.wilk@oracle.com, mcb30@ipxe.org, jgross@suse.com, andrew.cooper3@citrix.com, andriy.shevchenko@linux.intel.com, paul.gortmaker@windriver.com, xen-devel@lists.xensource.com, ak@linux.intel.com, pali.rohar@gmail.com, dvhart@infradead.org, platform-driver-x86@vger.kernel.org, mmarek@suse.com, linux@rasmusvillemoes.dk, jkosina@suse.cz, korea.drzix@gmail.com, linux-kbuild@vger.kernel.org, tony.luck@intel.com, akpm@linux-foundation.org, linux-ia64@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, rostedt@goodmis.org, jpoimboe@redhat.com Message-ID: <20160812072507.3cfdEbcliB_QVrkGI9w-Qpewix27j6wSjVsMwyFjI_A@z> On Fri, Aug 12, 2016 at 08:50:11AM +0200, Luis R. Rodriguez wrote: > On Fri, Aug 12, 2016 at 07:23:03AM +0200, Borislav Petkov wrote: > > On Fri, Aug 12, 2016 at 05:51:29AM +0200, Luis R. Rodriguez wrote: > > > OK I've added CONFIG_BUILD_AVOID_BITROT. > > > > What does that do? > > > Enabling it allows the forced compilation chosen by maintainers. > Otherwise forced compilations with the new special targets are > ignored. Nice. > I've gone with table-obj-y and table-lib-y as we have > to support both lib-y and obj-y respective targets. > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 33e2966dd741..7893e3b8da82 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1895,6 +1895,30 @@ config PROVIDE_OHCI1394_DMA_INIT > > See Documentation/debugging-via-ohci1394.txt for more information. > > +config BUILD_AVOID_BITROT > + bool "Always force building specially annotated" ...annotated targets" > + default y > + help > + If enabled then the the special table-* Makefile targets will always > + be forced to be compiled even if their respective CONFIG_ option has > + been disabled, but its objects will only be linked in if the same > + respective CONFIG_ option has been enabled. This helps avoid code > + bit rot issues, use for these targets should be carefully considred > + by maintainers. You can safely enable this option at the expense of > + increasing compile time slightly. Enabling this option helps avoid s/slightly// :-) > + code bit rot by taking advantage of the facilities provided and > + enabled by using linker tables documented under: > + > + include/linux/tables.h > + > + The special targets supported are: > + > + o table-obj-y > + o table-lib-y > + > + Say Y unless you are a grumpy maintainer and don't trust other > + maintainer's judgements on what code should always get compiled. ... or you're running a tiny-config setup ... or you're an embedded, resource-constrained person ... or you simply don't want to have stuff which is forcibly enabled on you even if you're never going to need it ... I got a million o'those :-) Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --