From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757148AbdDRSwz (ORCPT ); Tue, 18 Apr 2017 14:52:55 -0400 Received: from mga14.intel.com ([192.55.52.115]:64496 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752204AbdDRSww (ORCPT ); Tue, 18 Apr 2017 14:52:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.37,219,1488873600"; d="scan'208";a="847327060" From: Andi Kleen To: Josh Poimboeuf Cc: kbuild test robot , kbuild-all@01.org, linux-kernel@vger.kernel.org, Ingo Molnar , Steven Rostedt Subject: Re: arch/x86//kernel/ftrace.c:35:3: error: #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 References: <201704160947.iSmcgQi7%fengguang.wu@intel.com> <20170417133313.ibbt5nmp76xzabf4@treble> Date: Tue, 18 Apr 2017 11:52:41 -0700 In-Reply-To: <20170417133313.ibbt5nmp76xzabf4@treble> (Josh Poimboeuf's message of "Mon, 17 Apr 2017 08:33:13 -0500") Message-ID: <87lgqxtuo6.fsf@firstfloor.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Josh Poimboeuf writes: > > The error is working as designed. gcc < 4.6.0 doesn't have -mfentry, so > it fails the above check on x86. Can you add a skip rule? It should > skip building the following case: > > x86 && ((gcc < 4.6.0) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) > && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE This will also break everyone's randconfig builds. The better way would be to check this in the Makefile and disable one of the options -Andi