From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753234AbdEIDig (ORCPT ); Mon, 8 May 2017 23:38:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41384 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166AbdEIDie (ORCPT ); Mon, 8 May 2017 23:38:34 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D0F8CC04B31B Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx07.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jpoimboe@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com D0F8CC04B31B Date: Mon, 8 May 2017 22:38:31 -0500 From: Josh Poimboeuf To: Andy Lutomirski Cc: Linus Torvalds , Jiri Slaby , Andrew Morton , live-patching@vger.kernel.org, Linux Kernel Mailing List , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , the arch/x86 maintainers , Jiri Kosina Subject: Re: [PATCH 7/7] DWARF: add the config option Message-ID: <20170509033831.6zoplbhnidbix5ua@treble> References: <20170505122200.31436-1-jslaby@suse.cz> <20170505122200.31436-7-jslaby@suse.cz> <20170507165524.cdxfuwbd5alr7v6k@treble> <20170509013818.i2njk66mcgp4rtp7@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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 [10.5.110.31]); Tue, 09 May 2017 03:38:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 08, 2017 at 07:31:50PM -0700, Andy Lutomirski wrote: > On Mon, May 8, 2017 at 6:38 PM, Josh Poimboeuf wrote: > >> Also, don't you need some indication of which reg is the base from > >> which you find previous frame? After all, sometimes GCC will emit a > >> frame pointer even in an otherwise frame-pointer-omitting kernel. > > > > I don't think we *need* to do that. I believe the base reg can just > > always[*] be the stack pointer, even with frame pointers. > > What if there are functions that use alloca or variable length arrays > on the stack? Functions using AHASH_REQUEST_ON_STACK come to mind. Wow, mind blown. This is why I added you to CC! Ok, I guess we'll need to be able to use the frame pointer as a base reg. It should be easy anyway. -- Josh