From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760875AbdDSIMG (ORCPT ); Wed, 19 Apr 2017 04:12:06 -0400 Received: from terminus.zytor.com ([65.50.211.136]:45945 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760833AbdDSIMC (ORCPT ); Wed, 19 Apr 2017 04:12:02 -0400 Date: Wed, 19 Apr 2017 01:07:04 -0700 From: tip-bot for Josh Poimboeuf Message-ID: Cc: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, rostedt@goodmis.org, peterz@infradead.org, fengguang.wu@intel.com, jpoimboe@redhat.com, torvalds@linux-foundation.org, andi@firstfloor.org Reply-To: tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, andi@firstfloor.org, torvalds@linux-foundation.org, fengguang.wu@intel.com, jpoimboe@redhat.com, peterz@infradead.org, rostedt@goodmis.org In-Reply-To: <20170418214429.o7fbwbmf4nqosezy@treble> References: <20170418214429.o7fbwbmf4nqosezy@treble> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/build: convert function graph '-Os' error to warning Git-Commit-ID: a5859c6d7b6114fc0e52be40f7b0f5451c4aba93 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a5859c6d7b6114fc0e52be40f7b0f5451c4aba93 Gitweb: http://git.kernel.org/tip/a5859c6d7b6114fc0e52be40f7b0f5451c4aba93 Author: Josh Poimboeuf AuthorDate: Tue, 18 Apr 2017 16:44:29 -0500 Committer: Ingo Molnar CommitDate: Wed, 19 Apr 2017 09:57:23 +0200 x86/build: convert function graph '-Os' error to warning For pre-4.6.0 versions of GCC, which don't have '-mfentry', the '-maccumulate-outgoing-args' option is required for function graph tracing in order to avoid GCC bug 42109. However, GCC ignores '-maccumulate-outgoing-args' when '-Os' is also set. Currently we force a build error to prevent that scenario, but that breaks randconfigs. So change the error to a warning which also disables CONFIG_CC_OPTIMIZE_FOR_SIZE. Reported-by: Andi Kleen Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: kbuild test robot Cc: kbuild-all@01.org Link: http://lkml.kernel.org/r/20170418214429.o7fbwbmf4nqosezy@treble Signed-off-by: Ingo Molnar --- arch/x86/Makefile | 8 ++++++++ arch/x86/kernel/ftrace.c | 6 ------ 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index a94a4d1..49d160b 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -154,6 +154,14 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER else ifeq ($(call cc-option-yn, -mfentry), n) ACCUMULATE_OUTGOING_ARGS := 1 + + # GCC ignores '-maccumulate-outgoing-args' when used with '-Os'. + # If '-Os' is enabled, disable it and print a warning. + ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE + undefine CONFIG_CC_OPTIMIZE_FOR_SIZE + $(warning Disabling CONFIG_CC_OPTIMIZE_FOR_SIZE. Your compiler does not have -mfentry so you cannot optimize for size with CONFIG_FUNCTION_GRAPH_TRACER.) + endif + endif endif endif diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 0e5ceac..5b71535 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -29,12 +29,6 @@ #include #include -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) && \ - !defined(CC_USING_FENTRY) && \ - !defined(CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE) -# error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE -#endif - #ifdef CONFIG_DYNAMIC_FTRACE int ftrace_arch_code_modify_prepare(void)