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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 77709C43613 for ; Mon, 24 Jun 2019 07:11:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45E19205F4 for ; Mon, 24 Jun 2019 07:11:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="baaTIpEN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726340AbfFXHLz (ORCPT ); Mon, 24 Jun 2019 03:11:55 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:51544 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727426AbfFXHLz (ORCPT ); Mon, 24 Jun 2019 03:11:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=RQ35CdI7OgSCvNIJDvf1p+BfUv8hYylGCi0q85yv+Yw=; b=baaTIpENIFYajuYTAHyVtoJWM a1DUikSr096fgOD3KX66qiitLLwEMKxstZe8F41v2bSIUYioz/6i/Vb3pW05jvnSnC5RPE6dMcTgk FedZTCJIKdzczm2PnKEbJfSoyTfz35zM5fMJsM0iTkOxlNBkJIIR1i0sUUDu1qFJyoqUqf5O1fwMa l74AR53sr2mYYr4dztHj0eXb6WjQaYg+uj0apZv4X+6qDpy7TCzvXnv803NPjM0irg441yMX68Br0 7M3ZzB6dbVUOAGX2i68AXvhyavS/LvKi+Yk7Gl2BqJiPyfGlLda1wsZU/Dj3y2X8MalupSjMainTx eExFIV/+A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hfJ8O-0002ZO-91; Mon, 24 Jun 2019 07:11:24 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D17A920A021ED; Mon, 24 Jun 2019 09:11:21 +0200 (CEST) Date: Mon, 24 Jun 2019 09:11:21 +0200 From: Peter Zijlstra To: Phong Tran Cc: mark.rutland@arm.com, kstewart@linuxfoundation.org, songliubraving@fb.com, andrew@lunn.ch, nsekhar@ti.com, ast@kernel.org, jolsa@redhat.com, netdev@vger.kernel.org, gerg@uclinux.org, lorenzo.pieralisi@arm.com, will@kernel.org, linux-samsung-soc@vger.kernel.org, daniel@iogearbox.net, festevam@gmail.com, gregory.clement@bootlin.com, allison@lohutok.net, linux@armlinux.org.uk, krzk@kernel.org, haojian.zhuang@gmail.com, bgolaszewski@baylibre.com, tony@atomide.com, mingo@redhat.com, linux-imx@nxp.com, yhs@fb.com, sebastian.hesselbarth@gmail.com, illusionist.neo@gmail.com, jason@lakedaemon.net, liviu.dudau@arm.com, s.hauer@pengutronix.de, acme@kernel.org, lkundrak@v3.sk, robert.jarzmik@free.fr, dmg@turingmachine.org, swinslow@gmail.com, namhyung@kernel.org, tglx@linutronix.de, linux-omap@vger.kernel.org, alexander.sverdlin@gmail.com, linux-arm-kernel@lists.infradead.org, info@metux.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com, hsweeten@visionengravers.com, kgene@kernel.org, kernel@pengutronix.de, sudeep.holla@arm.com, bpf@vger.kernel.org, shawnguo@kernel.org, kafai@fb.com, daniel@zonque.org Subject: Re: [PATCH 01/15] arm: perf: cleanup cppcheck shifting error Message-ID: <20190624071121.GN3436@hirez.programming.kicks-ass.net> References: <20190623151313.970-1-tranmanphong@gmail.com> <20190623151313.970-2-tranmanphong@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190623151313.970-2-tranmanphong@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Sun, Jun 23, 2019 at 10:12:59PM +0700, Phong Tran wrote: > fix "Shifting signed 32-bit value by 31 bits is undefined behaviour > errors" > > [arch/arm/kernel/perf_event_v7.c:1080]: (error) Shifting signed 32-bit > value by 31 bits is undefined behaviour > [arch/arm/kernel/perf_event_v7.c:1436]: (error) Shifting signed 32-bit > value by 31 bits is undefined behaviour > [arch/arm/kernel/perf_event_v7.c:1783]: (error) Shifting signed 32-bit > value by 31 bits is undefined behaviour I don't think that is true; the kernel uses -fno-strict-overflow (which implies -fwrapv) and that takes away all the signed UB.