From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 295A6C4338F for ; Mon, 23 Aug 2021 20:18:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 13542613DB for ; Mon, 23 Aug 2021 20:18:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232408AbhHWUSt (ORCPT ); Mon, 23 Aug 2021 16:18:49 -0400 Received: from gate.crashing.org ([63.228.1.57]:60137 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232165AbhHWUSs (ORCPT ); Mon, 23 Aug 2021 16:18:48 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 17NKCUqC005302; Mon, 23 Aug 2021 15:12:30 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 17NKCOGl005277; Mon, 23 Aug 2021 15:12:24 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 23 Aug 2021 15:12:19 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/booke: Avoid link stack corruption in several places Message-ID: <20210823201219.GZ1583@gate.crashing.org> References: <20210823155837.GX1583@gate.crashing.org> <67a5be3f-a443-03eb-aa8e-a1fa6c0b3d3f@csgroup.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <67a5be3f-a443-03eb-aa8e-a1fa6c0b3d3f@csgroup.eu> User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 23, 2021 at 07:05:38PM +0200, Christophe Leroy wrote: > Le 23/08/2021 à 17:58, Segher Boessenkool a écrit : > >On Mon, Aug 23, 2021 at 07:53:01AM +0000, Christophe Leroy wrote: > >> /* Be careful, this will clobber the lr register. */ > >> #define LOAD_REG_ADDR_PIC(reg, name) \ > >>- bl 0f; \ > >>+ bcl 20,31,0f \ > >> 0: mflr reg; \ > >> addis reg,reg,(name - 0b)@ha; \ > >> addi reg,reg,(name - 0b)@l; > > > >The code ended each line with a semicolon before, for absolutely no > >reason that I can see, but still. Fixing that would be nice, but only > >doing it on one line isn't good. > > Sure, forgetting the semicolon broke the build. That's because the > backslash removes the newline. Ah right, one of the surprises you get from using the C preprocessor on non-C code :-) > The cleanest way I found to fix that quite of stuff is by using GAS macro, > as I did for LOAD_REG_IMMEDIATE() some time ago. Yeah, good plan. You can use loops and saner parameters etc. as well if you do :-) > >Btw. Both the 7450 and the modern cores implementing this really need > >this to be $+4, so it is a lot clearer to write that instead of 1f or > >a named label. > > I like that, removing unneeded labels will make it smoother and clearer. > I'll do it. Cool, thanks! Segher