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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 EB11AC433DB for ; Mon, 15 Mar 2021 11:15:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB24264E61 for ; Mon, 15 Mar 2021 11:15:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229721AbhCOLPG (ORCPT ); Mon, 15 Mar 2021 07:15:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:46462 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229536AbhCOLOh (ORCPT ); Mon, 15 Mar 2021 07:14:37 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id ADDC364E61; Mon, 15 Mar 2021 11:14:36 +0000 (UTC) Date: Mon, 15 Mar 2021 11:14:34 +0000 From: Catalin Marinas To: Valdis =?utf-8?Q?Kl=C4=93tnieks?= Cc: Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: arm64: kernel/sys.c - silence initialization warnings. Message-ID: <20210315111433.GA22897@arm.com> References: <162859.1615542946@turing-police> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <162859.1615542946@turing-police> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 12, 2021 at 04:55:46AM -0500, Valdis Klētnieks wrote: > Building arch/arm64/kernel/sys.o with W=1 throws over 300 warnings: > > /usr/src/linux-next/arch/arm64/kernel/sys.c:56:40: warning: initialized field overwritten [-Woverride-init] > 56 | #define __SYSCALL(nr, sym) [nr] = __arm64_##sym, > | ^~~~~~~~ > /usr/src/linux-next/include/uapi/asm-generic/unistd.h:29:37: note: in expansion of macro '__SYSCALL' > 29 | #define __SC_COMP(_nr, _sys, _comp) __SYSCALL(_nr, _sys) > | ^~~~~~~~~ > /usr/src/linux-next/include/uapi/asm-generic/unistd.h:34:1: note: in expansion of macro '__SC_COMP' > 34 | __SC_COMP(__NR_io_setup, sys_io_setup, compat_sys_io_setup) > | ^~~~~~~~~ > > We know that's pretty much the file's purpose in life, so tell the > build system to not remind us. This makes the 1 other warning a > lot more noticeable. > > Signed-off-by: Valdis Kletnieks > > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > index ed65576ce710..916b21d2b35b 100644 > --- a/arch/arm64/kernel/Makefile > +++ b/arch/arm64/kernel/Makefile > @@ -8,6 +8,7 @@ CFLAGS_armv8_deprecated.o := -I$(src) > CFLAGS_REMOVE_ftrace.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_insn.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_return_address.o = $(CC_FLAGS_FTRACE) > +CFLAGS_sys.o += $(call cc-disable-warning, override-init) We do similar initialisation in arch/arm64/kernel/sys32.c and arch/arm64/kernel/traps.c for example. It's a pretty common pattern throughout the kernel. So we either treat W=1 output as diff against the vanilla kernel when checking new patches or we remove override-init altogether from W=1. Mark Rutland pointed me to an older thread: https://lore.kernel.org/linux-arm-kernel/20190809083251.GA48423@lakrids.cambridge.arm.com/ -- Catalin