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,URIBL_BLOCKED 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 B1625C46460 for ; Tue, 14 Aug 2018 16:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59E1721709 for ; Tue, 14 Aug 2018 16:04:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 59E1721709 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org 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 S1732894AbeHNSwW (ORCPT ); Tue, 14 Aug 2018 14:52:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:58868 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728458AbeHNSwW (ORCPT ); Tue, 14 Aug 2018 14:52:22 -0400 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 99BE3215E5; Tue, 14 Aug 2018 16:04:35 +0000 (UTC) Date: Tue, 14 Aug 2018 12:04:33 -0400 From: Steven Rostedt To: Julien Thierry Cc: Torsten Duwe , Will Deacon , Catalin Marinas , Ingo Molnar , Ard Biesheuvel , Arnd Bergmann , AKASHI Takahiro , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH 1/3] arm64: implement ftrace with regs Message-ID: <20180814120433.1f5e8da1@gandalf.local.home> In-Reply-To: References: <20180810160043.9E45568C76@newverein.lst.de> <20180810160223.D360D68C76@newverein.lst.de> <2b5c1092-2cc0-00ec-ba3d-341dc61452b4@arm.com> <20180813220315.6e8dfc9c@vmware.local.home> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Aug 2018 09:33:52 +0100 Julien Thierry wrote: > On 14/08/18 03:03, Steven Rostedt wrote: > > On Mon, 13 Aug 2018 11:54:06 +0100 > > Julien Thierry wrote: > > > >>> --- a/arch/arm64/Makefile > >>> +++ b/arch/arm64/Makefile > >>> @@ -78,6 +78,15 @@ ifeq ($(CONFIG_ARM64_MODULE_PLTS),y) > >>> KBUILD_LDFLAGS_MODULE += -T $(srctree)/arch/arm64/kernel/module.lds > >>> endif > >>> > >>> +ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > >>> + CC_FLAGS_FTRACE := -fpatchable-function-entry=2 > >>> + KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY > >>> + ifeq ($(call cc-option,-fpatchable-function-entry=2),) > >>> + $(warning Cannot use CONFIG_DYNAMIC_FTRACE_WITH_REGS: \ > >>> + -fpatchable-function-entry not supported by compiler) > >> > >> Shouldn't this be an error? The option -fpatchable-function-entry has > >> been added to the CC_FLAGS_FTRACE, so any call to the compiler is gonna > >> break anyway. Or am I missing something? > > > > I'm guessing this adds a more informative message on that error. One > > will know why -fpatchable-function-entry was added to the CFLAGS. I'm > > for more informative error messages being a victim of poor error > > messages causing me to dig deep into the guts of the build > > infrastructure to figure out simple issues. > > > > Yes, I agree it is better to have this message. My point was that we > could have "$error" instead of "$warning" to stop the compilation right > away since we know everything is gonna break (and on parallel builds > this warning is gonna be drowned in compiler errors). > OK, I see what you mean. If the resulting build wont boot, then yes this should be an error and not a warning. -- Steve