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 20102CCD195 for ; Fri, 17 Oct 2025 13:37:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version: Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:Cc:To: Subject:Date:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5XuC4DMjljqzjiUOdzBpjppA2nysGfqfpd0GsJmLJmI=; b=PALiVBTyQaELkbcvtHLPyMrpAI 1AVhWOng4nPQH4WAVkxT1h1mtGZLQZwDjAoq6naniYVZdVt4+SjDi1TC/+XSxnQoH9HCZPwhTGHrK Tl4xZ3jT2Ly23DgJVSrtbqM2yBlB2efegxCZPVTAMKGBiq7HqQfiMGRFEc9POnz6V69n/FZ3ja+FK aPKrva0TYtsnaUFkrjJusbnWcxeXjpHtCMy+BhaSob5jbu2axfm6HGqvn7RMErhM4lGJ4gnzXIqc7 sQ4q6xe1mA+xrxX3hlEksG+rJ7wo1rDaE97odKN6gr6kP1hHhTE9lDSYfJ/YLHRIp8p94PJs96K8d 7zXCX+MA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v9keB-00000007x7w-4Axd; Fri, 17 Oct 2025 13:37:31 +0000 Received: from mail-centralusazlp170110009.outbound.protection.outlook.com ([2a01:111:f403:c111::9] helo=DM5PR21CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v9ke7-00000007x5m-40Gx; Fri, 17 Oct 2025 13:37:29 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=XkQ3Mx/kDdedd1L+FcwagJP0nfh6U1Qtk4PYvEdZNqV7ZX0E3Nf7KCZ5bY3BqDx7B8XNR8HCPZ7ZeZlKzcVEl1W+TfN3/FUBnSDkX+HWA2eP99VwlVzoxLTawuiboxOwR5AZenNDpKUtj5+nPG0rSsDSESLswvf2oyY29C6yZ1sh1QmA6vQhO27sDyB7q07AQXXEDQFYbXLg7eL0p796hAmeGK9Y8jhxaeBndSjovTyIFYv7cYBns4aSnQ5WeUzSQGSwx/VOvmrO/h6WHVxV/JLzvuI15pkLR8k4OIIIvNn1X7vyx0gdnmWHjqzda/B9axxeWLfZgrcWI/020kQVRA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=5XuC4DMjljqzjiUOdzBpjppA2nysGfqfpd0GsJmLJmI=; b=LJ9Qr8t+t1IfjEWbAMaIgf73hAvzQMRkjYQV2uCPfw3M7+eLroxvpu21oXMycgwY2eCFSmGrWc/gGojOX5ne2xS0/K1vuYVxNunrYT5Fk5+dfMZsO/DK6sCI0IsH9yJYxvoTo4Mw3DjmG2tvBcvQqvR7qhcQ0nc03Xum1Ouq23Kmw2CSXv3D6LOfd194cQ6RiykHnhkhBPkzJM3thHXYS33lQ6ccOkySI41RZe49x7lx7OMc5V6ltiyhnNXLsAV2lATC+1r2IEgeFHDb8oZDHvAqGKAB2j8tLhIdVD95roviB9+EL3uqGnTnA9m6PzUK+cxu7osPs6PzOICXpWv0MA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=5XuC4DMjljqzjiUOdzBpjppA2nysGfqfpd0GsJmLJmI=; b=sxkTAfo+RwhkujYNCkeBp/7hYCtSJhXc0R//hoqVKi082FNPiRcvSatJubXIDe9i//zh04naa9WFaFR86QFvKthiBQ8Vm4+Qk09LVgt8Tn3PEqr8iVt6VnDa+tc3kT+Rb1obUGnu7RAdc455LwZ36iY/e5qY9oOUscM30YMdgzs= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=citrix.com; Received: from DM4PR03MB7015.namprd03.prod.outlook.com (2603:10b6:8:42::8) by BN9PR03MB6188.namprd03.prod.outlook.com (2603:10b6:408:101::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9228.13; Fri, 17 Oct 2025 13:37:18 +0000 Received: from DM4PR03MB7015.namprd03.prod.outlook.com ([fe80::e21:7aa4:b1ef:a1f9]) by DM4PR03MB7015.namprd03.prod.outlook.com ([fe80::e21:7aa4:b1ef:a1f9%3]) with mapi id 15.20.9228.011; Fri, 17 Oct 2025 13:37:18 +0000 Message-ID: <41d62605-0d17-4504-8dae-8e9d126eb58b@citrix.com> Date: Fri, 17 Oct 2025 14:37:11 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [patch V3 11/12] x86/futex: Convert to scoped masked user access To: Thomas Gleixner , LKML Cc: x86@kernel.org, kernel test robot , Russell King , linux-arm-kernel@lists.infradead.org, Linus Torvalds , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , linuxppc-dev@lists.ozlabs.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Heiko Carstens , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, Mathieu Desnoyers , Andrew Cooper , Julia Lawall , Nicolas Palix , Peter Zijlstra , Darren Hart , Davidlohr Bueso , =?UTF-8?Q?Andr=C3=A9_Almeida?= , Alexander Viro , Christian Brauner , Jan Kara , linux-fsdevel@vger.kernel.org References: <20251017085938.150569636@linutronix.de> <20251017093030.506939239@linutronix.de> Content-Language: en-GB From: Andrew Cooper In-Reply-To: <20251017093030.506939239@linutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO4P123CA0656.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:316::12) To DM4PR03MB7015.namprd03.prod.outlook.com (2603:10b6:8:42::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR03MB7015:EE_|BN9PR03MB6188:EE_ X-MS-Office365-Filtering-Correlation-Id: 3f05f3db-2cef-4ec4-6132-08de0d824a64 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?c2tmZkRKZDZQVXcvNkRYN1BVYjc5SjhIUUovK2lQdGpIVFF0ZFU5SmUxNE41?= =?utf-8?B?T2IvUStkeWlSbmRTd3J5c3pvSlRJdHhhVGd3M29HMWpnOFhRYXdUbjhXU3JV?= =?utf-8?B?NUpzT2N0Mnd6Njk2UWxBY1R5YlZqa04wcElWeW9WZXpSN0tsVlpWNGM5N0Uy?= =?utf-8?B?NE0wZHVXblRVU3NrWHJtWXo4MGVOR05maHRSSWpPVU1jNmN5aUg5aGRiNjZQ?= =?utf-8?B?cVRzYjVmckQvY2psalpQRGwwaEpTbjVIdHB4V09PRFpMb3ErTmVoM3kxVWE1?= =?utf-8?B?U3RhR3I5bXEzTDU5cEI2QTRKcnVuQ1hWb1JGMHdQQlhyRXlJZzhSK2lyMG5o?= =?utf-8?B?MzVUd1RSZTBNMjZvQlNPbVptNUx2Yk4vb0o2QmRTNTh4d0lQWFNscUZERXhj?= =?utf-8?B?dHdSdWFDZTJ6WVlTMzVEekJLNmxpTnRJMWsrT1FQYmk4OVBLa3VRZngzNkFx?= =?utf-8?B?V3pNd3lYaGJSM1U5aTVHNnNLN2Q5dzFTUHJFWVNEN2hDSFN3SFVrRm5HdVZq?= =?utf-8?B?bVdycEEwKzJpUWV4WklNR2JHUnhlNnpuWWU0N2FESE8xY1U5dGFTZ04vNmpN?= =?utf-8?B?eUdaV1EyVlFXOG1mV0NnY09FcUlTNlY4RjFSM1lhaU91ZTZiVktPSE4yZS9p?= =?utf-8?B?cytUR3UxOEg5VHBQSWdmYnErd3RHdWcvYUZLOTN0UTJlL3RWdlVXektBbVlK?= =?utf-8?B?VVdWSjcrdHhuckk1dkJoNEY2aEVkbE1qTkpaUGU2Y1NKS09STmZZSDlKR25G?= =?utf-8?B?enZPQ3dtZTBaSjdkWWIxazlDRXc2QnNsWGphcXJxL1hScEZ5QUdLYTBTK0FW?= =?utf-8?B?RXJEZjcyb3gyMjQrQlVsazNqajY2cUNUUEtmN0xraGdYSE5BUlVEVDdGN1dl?= =?utf-8?B?N0VZUGE4eHJQbmNPak9aVlFWc2xMWE00SGZCNExyT1BqZmM3NGlpY3ZNZS8x?= =?utf-8?B?T0gvdS9zSUtZY3hHeEkrcGV0YjdXMTZjWmZ1NDBUektGcFdBckp0NzlZY0xl?= =?utf-8?B?SFF5b2dFQ2hBUlQzZUZvSGlUWFZpU0RYT1RMMmxQV29vSmMxbllFdDFGKzN6?= =?utf-8?B?T1hvdlZXWDVHbVpXZUU1cXlPK2lqcFhSMkMwZkd4N3dCbjIzVFVOeXkwN0dN?= =?utf-8?B?c01WamwyL3VZNW5WMjltYWEwMlFPM0ZXai9VT2dBcmhzK2lpb3pHaDQ3amVK?= =?utf-8?B?eGRnaEhaT3gwUTVHb2xLMnoyejFYeWQ3NHAzdjh0VzFCbXRXZi9hSFBaK2hB?= =?utf-8?B?ZEtyMGVDWlRuazYyWHdJZVhZSUh0bDBoTFZKNHlyOVkweHE1Nm8rRUdzZDB1?= =?utf-8?B?SmczK0NUTHI3Y0ZDYkZoMjZERGlNcGN5T1h0elpHTnEvM3IyRTZWSVFXL0ly?= =?utf-8?B?ZWNEbEdqVkhGZUVaMWtDQzdhYzlQNzVrSHdGSE90YXFXcVFER2VheEFqWDlK?= =?utf-8?B?WTM5ZDJzbkJKdWpId0FzbHhwSVNLbUpwUFNqSTlicXVSdkd1OXVDNGplQ0xq?= =?utf-8?B?UjlzSzcvalZWNGtUclVFd3Z0TUUyNGZuckZjNjZ5M3dyZXY0bENnKy9oTlpY?= =?utf-8?B?a1JkUkdwTkM2T2pvM0tFczh6VGlXKzlnZWRSZ3JQMmxkOFZwNnNpdkxRUU9M?= =?utf-8?B?Q1puZTViVk8zMmdveFlaVWNlR2xtRUYrWXBWdU9iTnNlM2Vub20wbEEzRVRh?= =?utf-8?B?WUJLR3JrNHhOODNoTWpCNC9ieFc1OG1qNE9Ba3JwUGdyVUJCOXZrakNIdFgr?= =?utf-8?B?OTFFTFNnY01wQ1gralMvNXE1Uml4a2YzTHVqajdsbjNaUG9aNDgvcXJ2R1Fk?= =?utf-8?B?MCtvRHFzc2hlSnFJY0ZnZnFFWkZmRnJhOU5rZnN1UloyYSs3dmt5V0VabWw3?= =?utf-8?B?RGJRdGxWNzVCb3RzdlgxUHd4SnZEMEV0dzZ6cVlTanlnRUpxSlV5eVhDamxj?= =?utf-8?Q?S1XGAINPlQBeujG5TRCw8oWkKsoN1Lo5?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR03MB7015.namprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?cXB0SGN0VXRyRERyL0hEYkdTc2dBUld1ckhDYUQveFZML2FDT01Jai9la0Y1?= =?utf-8?B?ZVN6Qk9Mb2trckE3WGtpbnZ4RHdYbmczZ0NzeDF2bkNEM0JKNXRSNVFrMXdJ?= =?utf-8?B?empadHI3RFEyT2g2Q01UTEdjRjF2NDJYdXBsWkRVVU5jZmxBZ2prNGRPTEJx?= =?utf-8?B?RXVwa1RzTnVlYmFqMklZMk5ZWVllT2l1V1N5RDBGU2dwRm03elJKTkZ4cGg2?= =?utf-8?B?d08wTDZjais0bzZQZmtSQitMZk9nVGJhWnFYRmZtTTUrN2xsR2o5aVdrbjBq?= =?utf-8?B?cXJTQ0djVUtJT3dMY1NZYVZKS2FVc3Z2WTRaUDl2WjBhcjJaSzNpNXNTVHlK?= =?utf-8?B?SFZBaWpSRUQzN1NuUGZrTVRyU2R3Z3l1QlU4RmFTWTg5eDBMUjl6R0IvOG5x?= =?utf-8?B?dGI0NzZWUkdITmRMOHZDYUg2V29ZWW1zVTRIYlBDRXRobWU2NmkxampGTVFE?= =?utf-8?B?emdPeGFsRkJFSlZLcGtkTThRZkYrczRYYjVEWFAwQjBnNHNsc0l4SWFMbS9l?= =?utf-8?B?c2FQUFlOOXlTNXFLa1h0OVNNK1NCZlNFcGYzSjZ6Q2c3ZW5FVGRhS05yVElw?= =?utf-8?B?U1QzdUx3c2VUUDBqNUVPYVd6ZWhoTjM2ajBoS0tNQlZIc2VxakJRc3B4MkxU?= =?utf-8?B?SVF2NXN3NjB2ZkxkTzFCdVJEbDJIaWFoVys3STArSFRFZnpBZDFUa3UyeTdh?= =?utf-8?B?OEtUVEMvb2hyWmlvRkVtczhEdStid0VmN3ZKT2I5bUxMWG5LblNjd2k3M3Az?= =?utf-8?B?WkxZaHZiY2RscGR4akUxakYwb1ZzN1hycE5XQmwvNXJtWE9iZlhMcFpOclZl?= =?utf-8?B?Rnk1MnVBTGV6WExxczNjazJNLzA1KzliYWJ2Yk44eE1ieTVHaGRnbThhNm5X?= =?utf-8?B?L2ZGOVJITWR3KzVPTSsydWpzNTQxSVdLSTZ3RG5Dd2Q0UjZjd2ZhTTlvdGhs?= =?utf-8?B?cHh5ZEZHQ3VBSW1pTFUyb1FtVHhJcjFKckVUYjFQbnhkZGRiWTJ4RTZMSy9J?= =?utf-8?B?NEp2T3RCNFV5V204RFdxQ1Y5V01lTEZUcnU3VkRlVExOL2ladTJCUHdNcE9y?= =?utf-8?B?TkpIVUdvSndjdTE4d09send6MGJOeUNpblMvTWNuNkhjNkpjNFlRTzdiYmdH?= =?utf-8?B?ZVRqbGpmWDM3NGlUdFh6anpBTE5aNkhhWFZWd2pmZmp5UHUzbDlkWkhKWUo3?= =?utf-8?B?bi84Mi9uWWZhbXRMbTdFSXFXTUxjcjhLTDJ5U2FQajVKWHgrQTEwZ2Q1UDZv?= =?utf-8?B?VWhSUUZSbjNibURiZW5HaTdUWStnOVVUZ2RlWWF0VzZiN3BEN0lMd0ltZTZ3?= =?utf-8?B?L25IWEwyRzFIbllmbWpudlJNRUppWjFMMGg1L3d6R2NWS2I4ZW5ZS0RZMlVV?= =?utf-8?B?NjRDc0VYck16dDJvZVlBNVg0RFlHM1l4aEMrMkhFK3Y5Z2tidjRZaFJieUhy?= =?utf-8?B?SGpCNmxIWVowYW16dkZoZFE3aVR0WmZESUluSDJ5YXlXZktwd1JCWmFFUXhj?= =?utf-8?B?ZHRCR2w2Kys1dVF0cGxzd3R3cFJmWDBvL0I0RjhVSlJtczJwaGRhdGRySTl2?= =?utf-8?B?VCtyYkFXaEkxb1NQUm5Fa04wMmN3azZqZ1FQaVArRisrRUQ2QnhxeCtKSVpV?= =?utf-8?B?V0ZwWUlHb2lNVlNMbURycXB5OEhoT0RpWmo2QkFmdkV6VmI5dzZsWHY0ekdh?= =?utf-8?B?aEZaN1I0c0EzdXVBNkJlUkk3V29RUkt3enpsQjh5Y0pvZFVGOFh4ZTdFa3cy?= =?utf-8?B?ZVNXU050Y2tDNzA3aG0wUjRyTVQ2MGZKTHFQM1N5M2pCYkpiNHp1cGNTVUxq?= =?utf-8?B?MW9aRnJndVcyNjI5S2FacWZ0bDJObE94eWdjL0hpQ0UvQ1NOVXIwUDE0MHhi?= =?utf-8?B?S3F1YVZaRi9MTTFReDhhR3VUMGI0Wm1Cam52UDUrNHIzRzNjM01IbG11dG5I?= =?utf-8?B?QlQ4aVVqWkk1VzFPY1h0ZHcvckZrOERRNDhOazZ0cmFaMWxjdEIzY0ZUdklh?= =?utf-8?B?Wk45SlRrdEt6ZXA5RlIwcGZmT0tVUUpNSUlVakI3TjNvenVKQWtNQmNqdmdz?= =?utf-8?B?cXFCOFo1V2hpRmdEQ0tnbzBXcERnbUpPTExQY0JnZDRnZWRnRW5BdzdiQnJx?= =?utf-8?B?Vjg1ZU1pYmQyMHVGRTVocE5RcElFZnJFZmdkaExlL3VYcEt1ZlFwTU1LMWI1?= =?utf-8?B?YlE9PQ==?= X-OriginatorOrg: citrix.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3f05f3db-2cef-4ec4-6132-08de0d824a64 X-MS-Exchange-CrossTenant-AuthSource: DM4PR03MB7015.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Oct 2025 13:37:18.0742 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 7w+LVgDiEi5H08F96saqMVESGhpij/KRd/P7vgP/u6FHC7DtBPMNWK7EbojapHiFEeJXxx1L8g+IyZ+CHjoOwWKIovT25mHBEhfUdGdtqWI= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN9PR03MB6188 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251017_063727_988480_3620A2C0 X-CRM114-Status: UNSURE ( 9.60 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 17/10/2025 11:09 am, Thomas Gleixner wrote: > @@ -86,21 +79,19 @@ static inline int futex_atomic_cmpxchg_i > { > int ret = 0; > > - if (can_do_masked_user_access()) > - uaddr = masked_user_access_begin(uaddr); > - else if (!user_access_begin(uaddr, sizeof(u32))) > - return -EFAULT; > - asm volatile("\n" > - "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" > - "2:\n" > - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \ > - : "+r" (ret), "=a" (oldval), "+m" (*uaddr) > - : "r" (newval), "1" (oldval) > - : "memory" > - ); > - user_access_end(); > - *uval = oldval; > + scoped_masked_user_rw_access(uaddr, Efault) { > + asm volatile("\n" > + "1:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" > + "2:\n" > + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %0) \ > + : "+r" (ret), "=a" (oldval), "+m" (*uaddr) > + : "r" (newval), "1" (oldval) > + : "memory"); Minor points, but as you're rewriting this, it wants to be asm_inline volatile. There's also a useless line continuation on the end of the ASM_EXTABLE which can be dropped. ~Andrew