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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 8980CECDE4B for ; Thu, 8 Nov 2018 15:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D57920827 for ; Thu, 8 Nov 2018 15:47:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D57920827 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727396AbeKIBXm (ORCPT ); Thu, 8 Nov 2018 20:23:42 -0500 Received: from mx2.suse.de ([195.135.220.15]:36856 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726595AbeKIBXl (ORCPT ); Thu, 8 Nov 2018 20:23:41 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id DB262AE5C; Thu, 8 Nov 2018 15:47:34 +0000 (UTC) Date: Thu, 8 Nov 2018 15:47:32 +0000 (UTC) From: Michael Matz To: Borislav Petkov cc: Yi Wang , tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, suravee.suthikulpanit@amd.com, puwen@hygon.cn, davidwang@zhaoxin.com, linux-kernel@vger.kernel.org, zhong.weidong@zte.com.cn Subject: Re: [PATCH v2] x86/cpu: fix prototype warning In-Reply-To: <20181108153226.GF7543@zn.tnic> Message-ID: References: <1541639548-11149-1-git-send-email-wang.yi59@zte.com.cn> <20181108150318.GD7543@zn.tnic> <20181108153226.GF7543@zn.tnic> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, 8 Nov 2018, Borislav Petkov wrote: > And frankly, I don't see why we should be fixing all those. So what if a > global function does't have a previous prototype declaration?! > > Micha, is there anything "useful" that warning bitches about or should > we disable it? What tglx said. If you don't intend such functions to be called from other units make them static, if you do intend them to be callable declare the properly. [There's also one subtle issue with argument promotions. prototypeless functions are called as if they are declared "int name()" that is default argument promotions take place (float->double, {char,short}->int), which won't happen with prototypes, and argument type conversions won't take place (as no parameter types are known). This might lead to different values between calling a prototyped and a prototype-less function arriving at the function even though the call expression looked the same] Ciao, Michael.