From patchwork Fri Jan 29 14:03:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Wagner X-Patchwork-Id: 8163591 Return-Path: X-Original-To: patchwork-linux-fbdev@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 002A39F440 for ; Fri, 29 Jan 2016 14:04:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5526D20253 for ; Fri, 29 Jan 2016 14:04:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D0272024F for ; Fri, 29 Jan 2016 14:04:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751412AbcA2ODl (ORCPT ); Fri, 29 Jan 2016 09:03:41 -0500 Received: from mail.bmw-carit.de ([62.245.222.98]:46625 "EHLO linuxmail.bmw-carit.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756166AbcA2ODj (ORCPT ); Fri, 29 Jan 2016 09:03:39 -0500 Received: from localhost (handman.bmw-carit.intra [192.168.101.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by linuxmail.bmw-carit.de (Postfix) with ESMTPS id 9482A59CFC; Fri, 29 Jan 2016 14:47:27 +0100 (CET) From: Daniel Wagner To: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Cc: linux-fbdev@vger.kernel.org, linux-mips@linux-mips.org, Marcelo Tosatti , Paolo Bonzini , "Paul E. McKenney" , Paul Gortmaker , "Peter Zijlstra (Intel)" , Thomas Gleixner , Steven Rostedt , Boqun Feng , Maik Broemme , Ralf Baechle , Daniel Wagner Subject: [PATCH tip v7 4/7] kbuild: Add option to turn incompatible pointer check into error Date: Fri, 29 Jan 2016 15:03:25 +0100 Message-Id: <1454076208-28354-5-git-send-email-daniel.wagner@bmw-carit.de> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1454076208-28354-1-git-send-email-daniel.wagner@bmw-carit.de> References: <1454076208-28354-1-git-send-email-daniel.wagner@bmw-carit.de> Sender: linux-fbdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP With the introduction of the simple wait API we have two very similar APIs in the kernel. For example wake_up() and swake_up() is only one character away. Although the compiler will warn happily the wrong usage it keeps on going an even links the kernel. Thomas and Peter would rather like to see early missuses reported as error early on. In a first attempt we tried to wrap all swait and wait calls into a macro which has an compile time type assertion. The result was pretty ugly and wasn't able to catch all wrong usages. woken_wake_function(), autoremove_wake_function() and wake_bit_function() are assigned as function pointers. Wrapping them with a macro around is not possible. Prefixing them with '_' was also not a real option because there some users in the kernel which do use them as well. All in all this attempt looked to intrusive and too ugly. An alternative is to turn the pointer type check into an error which catches wrong type uses. Obviously not only the swait/wait ones. That isn't a bad thing either. Signed-off-by: Daniel Wagner Acked-by: Peter Zijlstra (Intel) Cc: Thomas Gleixner --- Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Makefile b/Makefile index 9d94ade..adfb6a08 100644 --- a/Makefile +++ b/Makefile @@ -767,6 +767,9 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=strict-prototypes) # Prohibit date/time macros, which would make the build non-deterministic KBUILD_CFLAGS += $(call cc-option,-Werror=date-time) +# enforce correct pointer usage +KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types) + # use the deterministic mode of AR if available KBUILD_ARFLAGS := $(call ar-option,D)