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=-0.8 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 7C52AC4167B for ; Wed, 12 Sep 2018 18:37:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E1A620882 for ; Wed, 12 Sep 2018 18:37:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E1A620882 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 S1728149AbeILXn2 (ORCPT ); Wed, 12 Sep 2018 19:43:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:43886 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727651AbeILXn2 (ORCPT ); Wed, 12 Sep 2018 19:43:28 -0400 Received: from vmware.local.home (unknown [208.91.3.26]) (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 1D82020880; Wed, 12 Sep 2018 18:37:41 +0000 (UTC) Date: Wed, 12 Sep 2018 14:37:38 -0400 From: Steven Rostedt To: Paulo Zanoni Cc: linux-kbuild@vger.kernel.org, Vasily Gorbik , Michal Marek , Ingo Molnar , Tvrtko Ursulin , LKML Subject: Re: [PATCH v2] tracing/Makefile: fix handling redefinition of CC_FLAGS_FTRACE Message-ID: <20180912143738.0d6264ce@vmware.local.home> In-Reply-To: <20180910175956.22679-1-paulo.r.zanoni@intel.com> References: <20180910175956.22679-1-paulo.r.zanoni@intel.com> X-Mailer: Claws Mail 3.15.1 (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 Mon, 10 Sep 2018 10:59:56 -0700 Paulo Zanoni wrote: > As a Kernel developer, I make heavy use of "make targz-pkg" in order > to locally compile and remotely install my development Kernels. The > nice feature I rely on is that after a normal "make", "make targz-pkg" > only generates the tarball without having to recompile everything. > > That was true until commit f28bc3c32c05 ("tracing: Handle > CC_FLAGS_FTRACE more accurately"). After it, running "make targz-pkg" > after "make" will recompile the whole Kernel tree, making my > development workflow much slower. > > The Kernel is choosing to recompile everything because it claims the > command line has changed. A diff of the .cmd files show a repeated > -mfentry in one of the files. That is because "make targz-pkg" calls > "make modules_install" and the environment is already populated with > the exported variables, CC_FLAGS_FTRACE being one of them. Then, > -mfentry gets duplicated because it is not protected behind an ifndef > block, like -pg. > > To complicate the problem a little bit more, architectures can define > their own version CC_FLAGS_FTRACE, so our code not only has to > consider recursive Makefiles, but also architecture overrides. > > So in this patch we move CC_FLAGFS_FTRACE up and unconditionally > define it to -pg. Then we let the architecture Makefiles possibly > override it, and finally append the extra options later. This ensures > the variable is always fully redefined at each invocation so recursive > Makefiles don't keep appending, and hopefully it maintains the > intended behavior on how architectures can override the defaults.. > > Thanks Steven Rostedt and Vasily Gorbik for the help on this > regression. > I'll pull in this patch, but it's always a good idea to also Cc LKML (which I added to this email). I also updated the change log and added Vasily's acked-by. -- Steve > Fixes: commit f28bc3c32c05 ("tracing: Handle CC_FLAGS_FTRACE more > accurately") > Cc: Vasily Gorbik > Cc: Michal Marek > Cc: Steven Rostedt (VMware) > Cc: Ingo Molnar > Cc: Tvrtko Ursulin > Cc: linux-kbuild@vger.kernel.org > Signed-off-by: Paulo Zanoni > --- > Makefile | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/Makefile b/Makefile > index 4d5c883a98e5..a5ef6818157a 100644 > --- a/Makefile > +++ b/Makefile > @@ -616,6 +616,11 @@ CFLAGS_GCOV := -fprofile-arcs -ftest-coverage \ > $(call cc-disable-warning,maybe-uninitialized,) > export CFLAGS_GCOV > > +# The arch Makefiles can override CC_FLAGS_FTRACE. We may also append it later. > +ifdef CONFIG_FUNCTION_TRACER > + CC_FLAGS_FTRACE := -pg > +endif > + > # The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default > # values of the respective KBUILD_* variables > ARCH_CPPFLAGS := > @@ -755,9 +760,6 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ > endif > > ifdef CONFIG_FUNCTION_TRACER > -ifndef CC_FLAGS_FTRACE > -CC_FLAGS_FTRACE := -pg > -endif > ifdef CONFIG_FTRACE_MCOUNT_RECORD > # gcc 5 supports generating the mcount tables directly > ifeq ($(call cc-option-yn,-mrecord-mcount),y)