From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936204AbdIYReW (ORCPT ); Mon, 25 Sep 2017 13:34:22 -0400 Received: from mga14.intel.com ([192.55.52.115]:57348 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934743AbdIYReV (ORCPT ); Mon, 25 Sep 2017 13:34:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,437,1500966000"; d="scan'208";a="1018213857" Date: Mon, 25 Sep 2017 12:34:19 -0500 From: Miguel Bernal Marin To: Josh Poimboeuf 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: <20170925173419.GC27769@miguelinux-clr.zpn.intel.com> References: <20170906052613.30058-1-miguel.bernal.marin@linux.intel.com> <20170919233745.15343-1-miguel.bernal.marin@linux.intel.com> <20170920212418.lgjlm3h7gmxbrbz4@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170920212418.lgjlm3h7gmxbrbz4@treble> User-Agent: Mutt/1.9.0 (2017-09-02) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > -- > Josh -- Regards, Miguel Bernal Marin Open Source Technology Center https://clearlinux.org Intel Corporation