From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88C32C56201 for ; Wed, 21 Oct 2020 18:35:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D667208C3 for ; Wed, 21 Oct 2020 18:35:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504302AbgJUSfg (ORCPT ); Wed, 21 Oct 2020 14:35:36 -0400 Received: from smtprelay0071.hostedemail.com ([216.40.44.71]:51810 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2504248AbgJUSf3 (ORCPT ); Wed, 21 Oct 2020 14:35:29 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay06.hostedemail.com (Postfix) with ESMTP id CDAE918224D70; Wed, 21 Oct 2020 18:35:27 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: air39_5f006092724a X-Filterd-Recvd-Size: 5767 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf12.hostedemail.com (Postfix) with ESMTPA; Wed, 21 Oct 2020 18:35:25 +0000 (UTC) Message-ID: <3ec15b41754b01666d94b76ce51b9832c2dd577a.camel@perches.com> Subject: Re: GCC section alignment, and GCC-4.9 being a weird one From: Joe Perches To: Miguel Ojeda , Nick Desaulniers , lukas.bulwahn@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org, dwaipayanray1@gmail.com, Aditya Cc: Peter Zijlstra , Jakub Jelinek , Florian Fainelli , kernel test robot , Steven Rostedt , LKML , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , LKP , Kees Cook , "H.J. Lu" , Rasmus Villemoes , linux-toolchains@vger.kernel.org Date: Wed, 21 Oct 2020 11:35:23 -0700 In-Reply-To: References: <20200629003127.GB5535@shao2-debian> <20200630124628.GV4817@hirez.programming.kicks-ass.net> <20200630144905.GX4817@hirez.programming.kicks-ass.net> <58ff47cc-dc55-e383-7a5b-37008d145aba@gmail.com> <20201021080031.GY2628@hirez.programming.kicks-ass.net> <20201021131806.GA2176@tucnak> <20201021134436.GJ2628@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (adding cc's of kernel-mentees and a few checkpatch contributors) On Wed, 2020-10-21 at 19:54 +0200, Miguel Ojeda wrote: > On Wed, Oct 21, 2020 at 7:42 PM Nick Desaulniers > wrote: > > If you used some of the macros from > > include/linux/compiler_attributes.h like __section and __aligned, I > > would prefer it. Please consider spelling out __attribute__(()) an > > antipattern. > > +1, the shorthands should be used unless there is a reason not to (and > please write the reason in a comment in that case). Perhaps something to add as a generic test in checkpatch. Right now it checks separately for each __attribute__ use with any of aligned, section, printf and scanf. Likely it should include more of the #defines from include/linux/compiler_attributes.h. include/linux/compiler_attributes.h:#define __alias(symbol) __attribute__((__alias__(#symbol))) include/linux/compiler_attributes.h:#define __aligned(x) __attribute__((__aligned__(x))) include/linux/compiler_attributes.h:#define __aligned_largest __attribute__((__aligned__)) include/linux/compiler_attributes.h:#define __always_inline inline __attribute__((__always_inline__)) include/linux/compiler_attributes.h:# define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) include/linux/compiler_attributes.h:#define __cold __attribute__((__cold__)) include/linux/compiler_attributes.h:#define __attribute_const__ __attribute__((__const__)) include/linux/compiler_attributes.h:# define __copy(symbol) __attribute__((__copy__(symbol))) include/linux/compiler_attributes.h:# define __designated_init __attribute__((__designated_init__)) include/linux/compiler_attributes.h:# define __visible __attribute__((__externally_visible__)) include/linux/compiler_attributes.h:#define __printf(a, b) __attribute__((__format__(printf, a, b))) include/linux/compiler_attributes.h:#define __scanf(a, b) __attribute__((__format__(scanf, a, b))) include/linux/compiler_attributes.h:#define __gnu_inline __attribute__((__gnu_inline__)) include/linux/compiler_attributes.h:#define __malloc __attribute__((__malloc__)) include/linux/compiler_attributes.h:#define __mode(x) __attribute__((__mode__(x))) include/linux/compiler_attributes.h:# define __no_caller_saved_registers __attribute__((__no_caller_saved_registers__)) include/linux/compiler_attributes.h:# define __noclone __attribute__((__noclone__)) include/linux/compiler_attributes.h:# define fallthrough __attribute__((__fallthrough__)) include/linux/compiler_attributes.h:#define noinline __attribute__((__noinline__)) include/linux/compiler_attributes.h:# define __nonstring __attribute__((__nonstring__)) include/linux/compiler_attributes.h:#define __noreturn __attribute__((__noreturn__)) include/linux/compiler_attributes.h:#define __packed __attribute__((__packed__)) include/linux/compiler_attributes.h:#define __pure __attribute__((__pure__)) include/linux/compiler_attributes.h:#define __section(S) __attribute__((__section__(#S))) include/linux/compiler_attributes.h:#define __always_unused __attribute__((__unused__)) include/linux/compiler_attributes.h:#define __maybe_unused __attribute__((__unused__)) include/linux/compiler_attributes.h:#define __used __attribute__((__used__)) include/linux/compiler_attributes.h:#define __weak __attribute__((__weak__))