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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A03A3C4332F for ; Fri, 16 Dec 2022 17:19:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231530AbiLPRTy (ORCPT ); Fri, 16 Dec 2022 12:19:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230089AbiLPRTx (ORCPT ); Fri, 16 Dec 2022 12:19:53 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3799E29CAE; Fri, 16 Dec 2022 09:19:52 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C5D70621B9; Fri, 16 Dec 2022 17:19:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09401C433EF; Fri, 16 Dec 2022 17:19:48 +0000 (UTC) Date: Fri, 16 Dec 2022 12:19:47 -0500 From: Steven Rostedt To: David Laight Cc: 'Andreas Schwab' , "'Leizhen (ThunderTown)'" , Geert Uytterhoeven , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , "Joe Lawrence" , "live-patching@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , "Luis Chamberlain" , "linux-modules@vger.kernel.org" , Ingo Molnar , linux-m68k , "Jason A. Donenfeld" Subject: Re: [PATCH v9] kallsyms: Add self-test facility Message-ID: <20221216121947.7d03b651@gandalf.local.home> In-Reply-To: References: <20221115083349.1662-1-thunder.leizhen@huawei.com> <49070ac3-02bb-a3b3-b929-ede07e3b2c95@huawei.com> <4aaede14-8bd3-6071-f17b-7efcb5f0de42@huawei.com> <66ec4021-b633-09ba-73ee-b24cdb3fa25a@huawei.com> <06345dca-0afb-00a5-c9e9-5ba830d8ad05@huawei.com> <52450ec1da164d6d87587063c3b3d3d2@AcuMS.aculab.com> <592dce7a0de24c62bd31c29f86ce6c1b@AcuMS.aculab.com> <87pmcjidfe.fsf@igel.home> <1ba1fadb39994a4d91edabdfd9d69fa6@AcuMS.aculab.com> <87len7ibtt.fsf@igel.home> <87fsdfib07.fsf@igel.home> <819801284eb745d9a4189759bad297f5@AcuMS.aculab.com> <20221216115314.6120beb7@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Fri, 16 Dec 2022 16:57:54 +0000 David Laight wrote: > > I don't know m68k assembly, but I'm guessing the (%O)+ and the (%1)+ only > > modifies the register being used, and no memory is being touched. > > Memory is being read so a clobber is needed to ensure that all pending > writes have been done. > Although, in this case, the memory being read is effectively > read only so nothing should be I would think that if the memory being read is the address of what the input parameters being passed into it are, then the compiler should be smart enough to know that there's a relation. Especially if the input parameters are pointers. I assumed that "memory" was for memory unrelated to the input constraints. -- Steve