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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,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 D4B57C282DD for ; Thu, 9 Jan 2020 20:46:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8D832075D for ; Thu, 9 Jan 2020 20:46:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mGmbTjKX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728507AbgAIUqp (ORCPT ); Thu, 9 Jan 2020 15:46:45 -0500 Received: from mail-qt1-f195.google.com ([209.85.160.195]:46591 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728241AbgAIUqo (ORCPT ); Thu, 9 Jan 2020 15:46:44 -0500 Received: by mail-qt1-f195.google.com with SMTP id g1so7011574qtr.13 for ; Thu, 09 Jan 2020 12:46:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=DWM0j5tZLR3359c+a2rA4wyZv8TrqZcQKkaM1KEojEY=; b=mGmbTjKXlVt1lompbLHwd/o0loS1Ui1RASNS3ZCwAby7hncY8DP4zZqRNWujbFiPVQ 1Yre3YqeeOUg/RQ0swG4m3uPf4VRMXn2Egv5Bkn2Tc9MmRzAZBJf8iw/NdKj9DBFRAb0 8qFVdaEZaxzDO5k+ssPER1RiYQ2K7p+1U/mtE4SyLk3ZUrpsMtbkhton/QRPRKx/XS6g NiXbAUQTpmU1ctkhjmm2lpp7Ci4nuMX0i6NEJonIASaB/eOhaBAKm9efbNKMvAvUWLJn 0hSo2EQ4C8g5Fkz3Wu0LWh7Ri5gmJuxmoTw3Ob7uSiP+CXFjEKJ1mKyTJpwNLd8kVWF2 ZMow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=DWM0j5tZLR3359c+a2rA4wyZv8TrqZcQKkaM1KEojEY=; b=QxszFA5u6/TGpKsVbE8J815GqksFUmGRvXj+kVerx9+cxOCsL08JDLvsfIepWH8kZD 0Ome96lNwo1a+lnGNM8LJYOPZDUCFh7vBFfVUz3BqT6wlge7STmuLzvc3bPa+9UHJr0j LY1K6+nZf1dywTfMVEiNSBc4OsSVMRnzdhsHTY77i+VGwO9L8Iumo6t4lwWOq7xwsR+p 3045/4l4Q7/flyT8gAAp3IOzuXjIgnMku2mwVfzVa3zLG1c7e0NgZ4Gq6N/M1+H5sbgQ WI8syLeTyjxv0tHaKfQKD4vpWvUeEJCpbuUBe8hx7VUcVzf5lFaGl/GaReGa+2Uyu6dl oPWw== X-Gm-Message-State: APjAAAWzURR+ld/yFumLGF0xyZLaMoxzhy+CNhLje/OH2/gwOklLWUPL r6zLQKe4NY8AE3EHILh6h+6yw4PSG0Y= X-Google-Smtp-Source: APXvYqxybzWgUcYhtudbjmkLjeD3PtY/3I527wBsTWBCp1KPrdCi6Bg9T8RpSrIBmxeFmTbGWdc/HQ== X-Received: by 2002:ac8:37d3:: with SMTP id e19mr3173027qtc.361.1578602803027; Thu, 09 Jan 2020 12:46:43 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id f26sm3846724qtv.77.2020.01.09.12.46.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jan 2020 12:46:42 -0800 (PST) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Thu, 9 Jan 2020 15:46:41 -0500 To: Borislav Petkov Cc: Zhenzhong Duan , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Chao Fan , Dave Hansen , "Rafael J. Wysocki" Subject: Re: [PATCH v2] x86/boot/KASLR: Fix unused variable warning Message-ID: <20200109204638.GA523773@rani.riverdale.lan> References: <20200103033929.4956-1-zhenzhong.duan@gmail.com> <20200109184055.GI5603@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200109184055.GI5603@zn.tnic> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 09, 2020 at 07:40:55PM +0100, Borislav Petkov wrote: > On Fri, Jan 03, 2020 at 11:39:29AM +0800, Zhenzhong Duan wrote: > > Local variable 'i' is referenced only when CONFIG_MEMORY_HOTREMOVE and > > CONFIG_ACPI are defined, but definition of variable 'i' is out of guard. > > If any of the two macros is undefined, below warning triggers during > > build, fix it by moving 'i' in the guard. > > > > arch/x86/boot/compressed/kaslr.c:698:6: warning: unused variable ‘i’ [-Wunused-variable] > > How do you trigger this? > > I have: > > $ grep -E "(CONFIG_MEMORY_HOTREMOVE|CONFIG_ACPI)" .config > # CONFIG_ACPI is not set > > but no warning. Neither with gcc 8 nor with gcc 9. > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette The boot/compressed Makefile resets KBUILD_CFLAGS. Following hack and building with W=1 shows it, or just add -Wunused in there. diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 56aa5fa0a66b..791c0d5a952a 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -35,6 +35,9 @@ KBUILD_CFLAGS += $(cflags-y) KBUILD_CFLAGS += -mno-mmx -mno-sse KBUILD_CFLAGS += $(call cc-option,-ffreestanding) KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector) + +include scripts/Makefile.extrawarn + KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member) KBUILD_CFLAGS += $(call cc-disable-warning, gnu) KBUILD_CFLAGS += -Wno-pointer-sign