From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936403AbdIYTAr (ORCPT ); Mon, 25 Sep 2017 15:00:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44440 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933306AbdIYTAp (ORCPT ); Mon, 25 Sep 2017 15:00:45 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com EBF7012988C Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=jpoimboe@redhat.com Date: Mon, 25 Sep 2017 14:00:43 -0500 From: Josh Poimboeuf To: Miguel Bernal Marin Cc: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v3 0/6] locking/rwsem/x86: Add stack frame dependency for some inline asm Message-ID: <20170925190043.ub75ermaomaxyr32@treble> References: <20170906052613.30058-1-miguel.bernal.marin@linux.intel.com> <20170919233745.15343-1-miguel.bernal.marin@linux.intel.com> <20170920212418.lgjlm3h7gmxbrbz4@treble> <20170925173419.GC27769@miguelinux-clr.zpn.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170925173419.GC27769@miguelinux-clr.zpn.intel.com> User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 25 Sep 2017 19:00:45 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 25, 2017 at 12:34:19PM -0500, Miguel Bernal Marin wrote: > On Wed, Sep 20, 2017 at 04:24:18PM -0500, Josh Poimboeuf wrote: > > On Tue, Sep 19, 2017 at 06:37:39PM -0500, Miguel Bernal Marin wrote: > > > Some warning were showed by objtool using gcc 7.2.0 > > > > > > kernel/locking/rwsem.o: warning: objtool: up_read()+0x11: call without frame pointer save/setup > > > kernel/locking/rwsem.o: warning: objtool: up_write()+0x17: call without frame pointer save/setup > > > kernel/locking/rwsem.o: warning: objtool: downgrade_write()+0x22: call without frame pointer save/setup > > > > > > which means gcc placed an inline asm function and its call instruction before > > > the frame pointer setup. > > > > > > This series forces a stack frame to be created before the call instruction > > > by listing the stack pointer as an output operand in the inline asm statement. > > > > > > Also to be easy to maintain and understand the operands from the extended > > > assembler instructions were converted to named operands. > > > > I've got a patch going around which will change the way we do this, so > > you'll probably need to do a v3 after my patch gets merged. I'll add > > you to cc for the next revision. > > > > With your new patches (at v4.14.-rc2) the warning is not seen any more, > so I will send only the named operand patches (in separate thread), as > this fix is not more needed. Any chance you tested with GCC 7? With GCC 6 and older you might still see the warnings. -- Josh