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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 049CAC28D13 for ; Mon, 22 Aug 2022 07:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Subject:From:Cc:To:Date:Message-ID: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=CxT3LsaFel92Uml/R6QBJmrD8CBV6CXxyyPAUwO2wHM=; b=eOr29dGGG83eIk5binOXzLKhFw Xjn8L2i0PS5yVvCO2b0A+s9YVADHiReS10A3zk4RQxd4kH5VYRUJ4R0v7gTJ2DYK+VySu8J8R+nsF zPCo2IZpSEKvq0pzIQC0XvwMtcSluPqhp6mwYLWqw2a+rIvscp8nOXtW/pXc4cjvZFk1D/OPAE1N0 cCLjRDoZrI1VctRzTUOvwlEoCJjw444Qg9ouuXZWHu5u6S347L1+GcmNJhtg1yq44lOafRALe/Y38 OotKhuLtGixovHm+NQ+fDV4XFl5boOebmhJGe5F8Ms2GmqMe/DOnQVHqZ9DbeQvAHNu8RI1H5hXNy t6wFP8UA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oQ2GF-006ADF-Df; Mon, 22 Aug 2022 07:54:15 +0000 Received: from mail-dm6nam10on2045.outbound.protection.outlook.com ([40.107.93.45] helo=NAM10-DM6-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oQ2G7-006A7a-Ki for linux-arm-kernel@lists.infradead.org; Mon, 22 Aug 2022 07:54:10 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=cyCKA8u3wxbrsfvvJEkRVgx9tatGLXPcjqiR0Gsdjl6IhJuwxKQ8gl8ZBiWx6uVxhpZAwgK7ewA+47QGWxZaU0RyNTjQcgPqE6yeMh91p6Qof08Ifww5n7qF/aVy8M4GJrjSyd2aFT9syMFjQA4QRK0F8O8mEa/DfiNHJRj6p2CeZXTlSxQYZOecGFD/xYDoEBiH8hj9yxbVfbtrd2UuHLEOmCMdPqyJoTeJ7wr60k8RHLeEmh+NPe6Y++JKIGi2F8+F49ADXcIWyMdNnlFwZ5JgKB98Rc0WfHPjT0+NW5NlTlBKBvgn0zMiop9fvg4Tc/duSoRInc8Uu7c14mqQMw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=gluTfeGdc/w4m/MIElhZpTLIIQAhRLGT5uqTgwE/23s=; b=cTknvc54XkihyWsv5Tq1SkweJrnqBX/t+LdH1kwc6axy2KVVOK6Jb+GuwXxX55kx88VYSwGhv5W5DUrmiFaFuZxPq81SrabR0Gk+E3Vm70FzVo9r1p7SxPWvQuBrGqbF3OEkPdLrqQAblqOghllQzb4m1fFFbMyZIo3QvPWFOwI1GSDmnsc8xGVSRIZuzuY2CVdB5jVEoL7GLUKFLGsjpUyrlTih0MV+23faoSFsn1yL2U/TQuTFJpfAAG09dBQsXfwybTvz3E8p3M1MEKdfd+9P/p4O/e5eaeR4US4y8ZrZ4aFEhLy5ebeo0A+PXZ0KMSoZ6P/72NL3u+tFoy4d3g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=gluTfeGdc/w4m/MIElhZpTLIIQAhRLGT5uqTgwE/23s=; b=azuI7sg1kAc4U8gBAiwQURBiGGGLVIt+F0uqOfceVtbvjkJ8gnv6yMXfVQD5fGuIi1sq7p3KCWziRp2I+dQVeFTMy3LxVH3hv1UnyCv3fzpebHWw8P+wokgOVblsZ1LqmOdAJdSYJfMLiMOKleSwOtoLLYsi/4HMXt8Di5UX8CO+uVIAHBA5xF7cnLBZRG9b2KEKHtUV3ioIyX9GWurXTdM+jyu5g1NBZXTlxlEXJODSUe3q3K1SusyZAPc1KV9zAGuR2MxmrKnkDoAONZXKSfzbiTvKZlDd69oSzlPW0DepJ876x/0k3xM6dlTJmMxPQxm4jDo2Sz6EL+kmtifjIQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CY4PR12MB1366.namprd12.prod.outlook.com (2603:10b6:903:40::13) by BY5PR12MB3987.namprd12.prod.outlook.com (2603:10b6:a03:1a8::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5546.16; Mon, 22 Aug 2022 07:53:54 +0000 Received: from CY4PR12MB1366.namprd12.prod.outlook.com ([fe80::b9f8:7e48:f34a:70f9]) by CY4PR12MB1366.namprd12.prod.outlook.com ([fe80::b9f8:7e48:f34a:70f9%4]) with mapi id 15.20.5546.021; Mon, 22 Aug 2022 07:53:54 +0000 Message-ID: <2bea1a7b-935e-695d-ddaa-13eacda5672c@nvidia.com> Date: Mon, 22 Aug 2022 15:53:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.12.0 Content-Language: en-US To: catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org Cc: Yishai Hadas , Jason Gunthorpe , Maor Gottlieb , Leon Romanovsky , Michael Guralnik , Michael Berezin , yong.xu@arm.com, Eran Ben Elisha From: Mark Zhang Subject: Should we use "dsb" or "dmb" between write to buffer and write to register X-ClientProxiedBy: SG2PR02CA0081.apcprd02.prod.outlook.com (2603:1096:4:90::21) To CY4PR12MB1366.namprd12.prod.outlook.com (2603:10b6:903:40::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: b5c3f936-d63e-4f94-1dbf-08da8413757c X-MS-TrafficTypeDiagnostic: BY5PR12MB3987:EE_ X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CY4PR12MB1366.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(39860400002)(136003)(346002)(376002)(366004)(396003)(38100700002)(8936002)(5660300002)(2906002)(4744005)(36756003)(86362001)(31696002)(186003)(2616005)(6666004)(107886003)(6506007)(6512007)(26005)(316002)(54906003)(66476007)(66556008)(66946007)(8676002)(4326008)(478600001)(966005)(6486002)(41300700001)(31686004)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?RSsxTTJCWTViQkVKSHVTcjhtRWEvcXQ1TDVCbEhJc2FzdWhwTzRob0VTbndh?= =?utf-8?B?MEZ4cGR5OEI5WWN5U3Y0cVJhQ1ViSWNTVmhUeFFqY2dIS2NTQnB0VmtXNzgx?= =?utf-8?B?QlpMTWtxSVdsQ2tXUmFPWDltK01Hd1p1Q1lZQVlHN0FxRzdOa2RuWEVTdW0y?= =?utf-8?B?LzBWYnRjYkh0MitLUm1vNFEwd2dBeWVCYnhORUxXeUpGaWdpZkZNcXVCek0w?= =?utf-8?B?RDhUS3hQRVZaQ2w1Z3MrMjQ2dXNDbUlDL2cxR1g3djBMVWx3dE8wRDN1cXNr?= =?utf-8?B?M2NTeG14aThBQTBBbnE4ZkpEMjVsVDVOcUEraGt4TnF2WW0yNitEQWszT1p4?= =?utf-8?B?WFpnRUZZVmtZamp4TkRnT0ZmOURqV05YWW9jaXhhUC9sM2ZTdG1sWUF4WEhs?= =?utf-8?B?eXU4M0lPbHNVWlNOTUJjblA1YTh1dXMwa2tqaUd6WTVjM2pzdldMbGk2dXdk?= =?utf-8?B?ZmdaaGJBWVB1MzFrRmM3TFNTdWxibWxsSS82SnhlZU1CQTkyTy80ZHcwVnpt?= =?utf-8?B?KzVGcFFQamRjYkV0MVdwajgwSFJaTE1sOWRIN1RzNEY2YlpmMlROMjJsNVZB?= =?utf-8?B?VThJWU9QVVRsUmthNEw3aXRraC9nK0Qrd0tiT0MweTN2N3NlUnNHZDNNOXl5?= =?utf-8?B?bDF6ZHp6OFhETG4zWVo2TFVobzYwNkI2Q0JiRjhmQ2pqK2NOYVR4NHRlTCt0?= =?utf-8?B?SU1qZ2RpTys2eVNZelZ1cDFSTll6SmVtcHUrRDNLSEtrMHQwdUluNjJRdVFw?= =?utf-8?B?YUZjMS93R1pId2JKV0pyWGxUeWtMV0NLeWRBa3dyRjRpbHpqU0hRUnRkRUlT?= =?utf-8?B?VVMzME50SEdHQnRhOEdNME5QdFNNTklvdndwRVdyc2pySytjZllVbWl4L0pw?= =?utf-8?B?SkIrTXg5b2hacnRacFoybDZHTHV4eS9rM2sxOGhYczhUSEx1OGhaVGtkdVdo?= =?utf-8?B?bDhFdStPeXg2YWhjTlc0VDZ3ekdtcWgyN0ZWV3IzYzhuRlRyUFRnYTdlZjZq?= =?utf-8?B?RUh1UEF0RmplYksvZUNGbGF0ZE12VTlnSVJ5Y0tCcXJ0ZXlEZHpNZ20wYUlx?= =?utf-8?B?Qm04RkVaNlpxN1R0YUIzb3hEcTdBZmRlR2dwb0dvUEwvdDVFTGJFc2tMOElu?= =?utf-8?B?amM2cHA5c2l5aTZFc0hiOVY0eFhCK1FoVytqTFY2QXNXM1pqcHBUUjl2eGR2?= =?utf-8?B?bVh6VnJnaGV0RVNTV2g5K3lHYTFJMmltZVdlU1pIelpzVGlqaUZjUkFhM0pS?= =?utf-8?B?VXFaSDZ4ZWwyQ2VpZzE0bGZRbU94UVAxL0hDekc3NHRsY2llZHJyaitDWldo?= =?utf-8?B?ZldDQzVQUlBxOFZNTVk2NzNFaXhvWFo5cmlyNkIyUjY5aFNhbVBoTGFRVnNw?= =?utf-8?B?QzFKR3VtS0VwbjdMQkROVnVqZWt2SHdxZDhoSXZET204WHpKUmkrcU55cEky?= =?utf-8?B?SnR2ektycDRCSGZQTXU0TzJHTEd0SHVQL01jNm1QSGVpRUdudFlKbVNHcVhq?= =?utf-8?B?YXNFbTlIdXYrd2RFZFQrbUVJUXgyNU9lMmY2L0VjeHNuTVJUVFN5WTZYV0dh?= =?utf-8?B?UEI4eGVuc2JEaUNid2QxbWNCZk9lOU5XQTFPTmJBeHVHS2V4T0dxYU1LOE84?= =?utf-8?B?RjhlQUVXK1kzUllYQ28zeVo3OWd1UTRsZ3YySmpvTkZUY3dMc0hUUWhNT1Y4?= =?utf-8?B?MTh0R1NCMituZ2YxQXU0VEdCV083aGN5WTlRN2wvYlJqOU1SNUlxaUY1MFNk?= =?utf-8?B?SS80VkpnQmh1a1VtKzJRMTFRYzNXUnVHWUJrWkkzNW5zYnpXMGFSVTgwamUw?= =?utf-8?B?SStoRitlZVljejFJMTVONTVJcjlUQzcrbXcyeFJ2Vlh0OVAvRWUzRWk0ckQ1?= =?utf-8?B?V1hBalJxMHh4bWFPem9CcG1OUkFKYXozeTA2U1VZVXNTVjdQWWxpRXByRlAz?= =?utf-8?B?L1ZBZmtva0ZJQXltbm4vUEdpZnVTUm5PcXBLTmNtWGlKVTJqaXpxeDBVSitl?= =?utf-8?B?bWF0cE1NR0ZoUEVaNUMyMktkWGUrTlFMSEd4YkxEa0NDVDcrL0RNRThFcVRs?= =?utf-8?B?Q3ViRTk3dmJDQTR2L3VBYTVvK2FyYXdBUmJnUVRpRVRBdU81U0RqeGhOVlZU?= =?utf-8?Q?S9E9rwc5zaKnoM6HSY6rFdXWs?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b5c3f936-d63e-4f94-1dbf-08da8413757c X-MS-Exchange-CrossTenant-AuthSource: CY4PR12MB1366.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Aug 2022 07:53:53.9784 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: fUl8B4dfiGKNkwXNArlODA7rZ1/t7zkMP484gNoGlMNIACNFqIczxaJRrqt4b7YcLCFLqmOFVWs38W0OoOhARQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB3987 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220822_005408_386197_4BD203A0 X-CRM114-Status: UNSURE ( 6.75 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi ARM experts, May I consult when to use dsb or dmb in our device driver, thanks: For example when send a command a FW/HW, usually we do it with 3 steps: 1. memcpy(buff, src, size); 2. wmb(); 3. write64(ctrl, reg_addr); IIUC in kernel wmb() is implemented with "dsb st". When we change this to "dmb st" then we get better performance, but we are not sure if it's safe. I have read Will's post[1] but still not sure. So our questions are: 1. can we use "dmb" here? 2. If we can then should we use "dmb st", or "dmb oshst"? Thank you very much. [1] https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git/commit/?id=22ec71615d824f4f11d38d0e55a88d8956b7e45f _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel