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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0036EC433F5 for ; Wed, 15 Dec 2021 10:41:19 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.247321.426447 (Exim 4.92) (envelope-from ) id 1mxRiO-0007qd-Vg; Wed, 15 Dec 2021 10:40:52 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 247321.426447; Wed, 15 Dec 2021 10:40:52 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mxRiO-0007qW-SY; Wed, 15 Dec 2021 10:40:52 +0000 Received: by outflank-mailman (input) for mailman id 247321; Wed, 15 Dec 2021 10:40:51 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mxRiN-0007qN-EK for xen-devel@lists.xenproject.org; Wed, 15 Dec 2021 10:40:51 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-sth1.inumbo.com (Halon) with ESMTP id 77b091e3-5d93-11ec-9e60-abaf8a552007; Wed, 15 Dec 2021 11:40:49 +0100 (CET) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 92CE56D; Wed, 15 Dec 2021 02:40:48 -0800 (PST) Received: from [10.57.5.111] (unknown [10.57.5.111]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7520C3F5A1; Wed, 15 Dec 2021 02:40:47 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 77b091e3-5d93-11ec-9e60-abaf8a552007 Subject: Re: [PATCH] xen/arm64: Zero the top 32 bits of gp registers on entry... To: Jan Beulich Cc: Stefano Stabellini , Volodymyr Babchuk , Bertrand Marquis , xen-devel@lists.xenproject.org, Julien Grall References: <20211206142032.27536-1-michal.orzel@arm.com> <6ab797ce-86dc-2c32-1cd0-417fab7516c7@suse.com> <73913bdf-7449-34fb-b86b-662774cb3e62@xen.org> <865fb3a7-76fc-24da-e07d-c6e59e3e1abe@arm.com> <3aae0020-938e-d5fe-7d7f-d5d1c8335a24@xen.org> <447b6c54-7d0c-132f-6202-c1ae7fb16e5d@arm.com> <871bda7e-3f94-a5bd-3caa-16b0c8f6d693@suse.com> <87080c9d-803d-608a-1c5a-2102f014d2bc@xen.org> <1fcc18d4-70ce-12d1-6d54-ae82e511a4d7@xen.org> <040a1871-08ee-00e9-b46f-ca4854e8a541@arm.com> <82557218-539b-204a-a1a7-7c796a2baa8a@suse.com> <9dc003f8-4dd0-282f-61ce-6ca74c543f20@arm.com> <6e54f971-84c3-3635-12c8-643b619b2b53@suse.com> From: Michal Orzel Message-ID: <219d27fe-4e77-59f5-b559-4bc70c2a0399@arm.com> Date: Wed, 15 Dec 2021 11:40:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <6e54f971-84c3-3635-12c8-643b619b2b53@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 15.12.2021 11:32, Jan Beulich wrote: > (Re-sending an abridged version, as apparently spam filters didn't like > the original message with more retained context; I'll have to see whether > this one also isn't liked. Sorry.) > > On 15.12.2021 10:48, Michal Orzel wrote: >> This patch and the problem it solves is about clearing top 32bits of all gp registers so not only x0,x1. > > That's well understood. Yet for everything still in registers simply > using mov ahead of the respective push (as you had it) is still > preferable imo. > > Jan > In that case let's wait for Julien's opinion to decide whether I should get back to the previous solution with mov or to the stack solution. Cheers, Michal