From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Date: Tue, 25 Jun 2019 06:05:20 +0300 Subject: [Buildroot] [PATCH v4 02/15] linux: disable Werror for powerpc kernels In-Reply-To: <87imsukaei.fsf@dell.be.48ers.dk> References: <20190620100725.105587-1-giulio.benetti@micronovasrl.com> <20190620100725.105587-3-giulio.benetti@micronovasrl.com> <87imsukaei.fsf@dell.be.48ers.dk> Message-ID: <87blympdov.fsf@tarshish> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hi Peter, On Mon, Jun 24 2019, Peter Korsgaard wrote: >>>>>> "Giulio" == Giulio Benetti writes: > > > From: Romain Naour > > From patch [1] included in kernel >= 5.0: > > "The upcoming GCC 9 release extends the -Wmissing-attributes warnings > > (enabled by -Wall) to C and aliases: it warns when particular function > > attributes are missing in the aliases but not in their target. > > > In particular, it triggers for all the init/cleanup_module > > aliases in the kernel (defined by the module_init/exit macros), > > ending up being very noisy. > > > These aliases point to the __init/__exit functions of a module, > > which are defined as __cold (among other attributes). However, > > the aliases themselves do not have the __cold attribute. > > > Since the compiler behaves differently when compiling a __cold > > function as well as when compiling paths leading to calls > > to __cold functions, the warning is trying to point out > > the possibly-forgotten attribute in the alias." > > > Werror is set by default while building ppc kernel [2], but > > some warning can be introduced while building current kernel with > > newer compiler (for example building kernel 4.19 with gcc 9.1). > > > For the same reason why we remove Werror in packages's compiler > > flags. Building with Werror is not bulletproof when we start > > using a newer compiler that introduce new warnings. > > This is the case here. > > > Also this option is a bit strange since it's specific to ppc kernels: > > "The intention is to make it harder for people to inadvertantly > > introduce warnings in the arch/powerpc code." > > Other kernel developers on other arch may be interested by a > > similar/more generic option. > > > So, It's clearly intended for kernel developers. > > > Instead of backporting this patch [1] to kernel 4.19, select > > unconditionally the Kconfig option CONFIG_PPC_DISABLE_WERROR > > that allow to disable Werror. > > > Fixes: > > https://gitlab.com/kubu93/toolchains-builder/-/jobs/205435741 > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=a6e60d84989fa0e91db7f236eda40453b0e44afa > > [2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=ba55bd74360ea4b8b95e73ed79474d37ff482b36 > > [3] https://gitlab.com/bootlin/toolchains-builder > > > Fix-suggested-by: Yann E. MORIN > > Signed-off-by: Romain Naour > > Signed-off-by: Giulio Benetti > > --- > > v2: add a shared fragment in board/fragments/linux and update > > qemu ppc* defconfigs. (Arnout) > > > v3: commit log (Yann) > > enable the option from linux.mk instead of the defconfig. > > Committed to 2019.02.x and 2019.05.x, thanks. It is in 2019.02.x, but not in 2019.05.x as of commit 1818dae1e0. baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.52.368.4656, http://www.tkos.co.il -