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 4A712CAC59A for ; Thu, 18 Sep 2025 09:12:18 +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:In-Reply-To: Content-Type:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kRpsnlyh9RR02TMEXwYSS87r1gsTi3X06DXicCX4jzk=; b=RAS02UX9O6cwfzG6COsj4JnOdL LzslSHTPrPjtikgA8ooEI4Pwgah/YRYOuuJPMmx5TNZRUWF/yX226GN2Yy13izE94zWR6JMUpqSRb im2RQyDEaGuMm0w3tj4T9GpzPBjZHdGTAO2eUa8VthkvLNCHDV4UdL38FwKJIh/ZAYaHLt9MCMYkm 2TCUyQj/hHq/2SKanNaOP19OcnlWYUH4aohhNNep+W26oXVqpHNldLV7+4A6KZA9AG7khAr5VlZSo GLNWROcrA4eKQcXCs28RhKRkqX7pmTaU0DL0h+ygE3MFYWwrpGwaodblBfHv8gxc4uOJElVItXGki 59dMbQow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzAgV-0000000Gp72-2kP6; Thu, 18 Sep 2025 09:12:11 +0000 Received: from mail-westeuropeazlp170110003.outbound.protection.outlook.com ([2a01:111:f403:c201::3] helo=AS8PR04CU009.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzAgS-0000000Gp68-3qCb for linux-arm-kernel@lists.infradead.org; Thu, 18 Sep 2025 09:12:10 +0000 ARC-Seal: i=2; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=pass; b=cQ2qI9VnAVSMCQ+mC6bjoymxtPm65BGkyaC29AkHTQ2PuMPzpSIcz03UdKoCK5HzLawho4EdmMzKz68lRl1HnMjRco55e9fXhD/06WI79rQ+HaNGCqYPSO0H3LZM52zpa88ofZGH+eX70YNtKTEKcQjEy/WVG+LqPW3iaCmdcCZR7KB7oNhMXO6dCgFf05PmRQJBQOPuc8aVdcNpTyYopYVug4VuI2ITPlLI6et4mpy8h5qo3R1SKmiLdKOAQHpysTH806qZNp6hkfESzTe5oV4o+YbwYFIGO+1GIFlzCvRQLGvoj+AAz9b53UWKLhOLJToBDJ1+grTYdf0i/uJSMQ== ARC-Message-Signature: i=2; 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=kRpsnlyh9RR02TMEXwYSS87r1gsTi3X06DXicCX4jzk=; b=PA4KhrQSqYrMsEOm882ZfKrqoNoWqrZV+m9Xon1PU02lBM0OS3BCwWeDSilH7445wFgQ9j50cDsaclDYTDt6ld6ZwINuwczUGioOlf6of2Bi9NNTGpehqysSDZkIhI/8b5CYRZlC8E/D5zIvTgryCSj+GkeN60IMN4uem8RF/xsX/A58Mqva0JJZQU6uWSRhnE5bAmPsq5MvEvVuQdKZOWBBxg9bYGqsRR1J3MnD4h/DG+6kMQvtCRX6werr6/DrXAW2UESHMo78Vih4A6xa8JvBeru4YM2fEQw/QncQVGNTny0vKParUjKwTDAqs8qNVJN0zQzQZDYgy5RqqzG7zw== ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 4.158.2.129) smtp.rcpttodomain=kernel.org smtp.mailfrom=arm.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=arm.com; dkim=pass (signature was verified) header.d=arm.com; arc=pass (0 oda=1 ltdi=1 spf=[1,1,smtp.mailfrom=arm.com] dkim=[1,1,header.d=arm.com] dmarc=[1,1,header.from=arm.com]) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kRpsnlyh9RR02TMEXwYSS87r1gsTi3X06DXicCX4jzk=; b=YhCm0Us5QlRrG2caeX4xcIpAyW7aDVKDmnBFsqMxsc20ecW+9N69SPgt6wXZXEVn3lG4uyiWOXGT/GWc+MN2snLFxlDJlPY1RIXnbc2Gl94pSp6pxmZmlIFQ6SmujLGjR7MkgM8tgjc6kmypvQaa7oH14WhLRjfMM2UER/UYJ7w= Received: from DB6PR0301CA0091.eurprd03.prod.outlook.com (2603:10a6:6:30::38) by VI1PR08MB5488.eurprd08.prod.outlook.com (2603:10a6:803:137::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.13; Thu, 18 Sep 2025 09:11:59 +0000 Received: from DB1PEPF000509F8.eurprd02.prod.outlook.com (2603:10a6:6:30:cafe::6) by DB6PR0301CA0091.outlook.office365.com (2603:10a6:6:30::38) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9115.20 via Frontend Transport; Thu, 18 Sep 2025 09:11:59 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 4.158.2.129) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=arm.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 4.158.2.129 as permitted sender) receiver=protection.outlook.com; client-ip=4.158.2.129; helo=outbound-uk1.az.dlp.m.darktrace.com; pr=C Received: from outbound-uk1.az.dlp.m.darktrace.com (4.158.2.129) by DB1PEPF000509F8.mail.protection.outlook.com (10.167.242.154) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9137.12 via Frontend Transport; Thu, 18 Sep 2025 09:11:59 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=og1CPJ8FxBUT0GVP2yUP6tRMU67qk5fl1b/keouGBxzTdYJPH9dAuznN4E7wcvcl4IOxZHm/UH00TEPcIzFO3e89cOlWhZrVykjAKplsZeoLr3t4jNYZOYHVy76eLTOjBRxAHVzzXun5jq6fBgnF9/Fz3vfoe9lWS/VtXvwQevzasG33bhyyjxqSQxemeQU3F73iT/KK7PtZPMuUJcOT6n5cv30vUpOggIeTGAhmGj7dORRd2vBRtIM4pkvf889q5+hoDLenPhWKgPhiab8Bq8Tc/S88Lww0c2joPLdyENi/OhiUdAlDJbJftjRR0JEWEkbyNTmLqvyVVsOXNHr2Xw== 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=kRpsnlyh9RR02TMEXwYSS87r1gsTi3X06DXicCX4jzk=; b=sm++ChS1gcU9wOrkSb/Y+29UC1iUfQNYzKwzosu7HpU9B3Om7U8JJO+8Sa+GVjSjStDtvHiGEnMeR6mDN+I2qNOp9l93KGeaySRrwIx+EyYRdLfj4WgZ+NxNnOcR7Sy9LCjzJPyqJhSYaN8ocC7wSr72Qvx2X02GJkCy8jc5nwQebNT+TwMK/PEz5C1JgkeNvkwfAtob+D2p9HeE5rn2ffkKvWZHWyGNgZrnkQmdNejh9Nra7lWu7GspsfzOzvYjEkHq5SEiHhiX/KjlIkdipFIAAv1bJqAkiJmhxut3vftR0STa89Eu2XpTcq6NKVZNbCSpc8UulOQwnVr0vJWIxA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kRpsnlyh9RR02TMEXwYSS87r1gsTi3X06DXicCX4jzk=; b=YhCm0Us5QlRrG2caeX4xcIpAyW7aDVKDmnBFsqMxsc20ecW+9N69SPgt6wXZXEVn3lG4uyiWOXGT/GWc+MN2snLFxlDJlPY1RIXnbc2Gl94pSp6pxmZmlIFQ6SmujLGjR7MkgM8tgjc6kmypvQaa7oH14WhLRjfMM2UER/UYJ7w= Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; Received: from GV1PR08MB10521.eurprd08.prod.outlook.com (2603:10a6:150:163::20) by GV1PR08MB9915.eurprd08.prod.outlook.com (2603:10a6:150:3d::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.13; Thu, 18 Sep 2025 09:11:24 +0000 Received: from GV1PR08MB10521.eurprd08.prod.outlook.com ([fe80::d430:4ef9:b30b:c739]) by GV1PR08MB10521.eurprd08.prod.outlook.com ([fe80::d430:4ef9:b30b:c739%3]) with mapi id 15.20.9137.012; Thu, 18 Sep 2025 09:11:24 +0000 Date: Thu, 18 Sep 2025 10:11:21 +0100 From: Yeoreum Yun To: Mark Rutland Cc: catalin.marinas@arm.com, will@kernel.org, broonie@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, james.morse@arm.com, ardb@kernel.org, scott@os.amperecomputing.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 5/5] arm64: futex: support futex with FEAT_LSUI Message-ID: References: <20250917110838.917281-1-yeoreum.yun@arm.com> <20250917110838.917281-6-yeoreum.yun@arm.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: LO4P123CA0143.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:193::22) To GV1PR08MB10521.eurprd08.prod.outlook.com (2603:10a6:150:163::20) MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: GV1PR08MB10521:EE_|GV1PR08MB9915:EE_|DB1PEPF000509F8:EE_|VI1PR08MB5488:EE_ X-MS-Office365-Filtering-Correlation-Id: 9221b7f0-a43f-4a57-67e1-08ddf6936c2a x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0;ARA:13230040|366016|376014|1800799024|7416014; X-Microsoft-Antispam-Message-Info-Original: =?us-ascii?Q?7pm0cS7TxEsqNT0I90uriyN7/N+q5feInZYES9FCnZUkdbKPRUT4SG7qNeGY?= =?us-ascii?Q?Qt0seR3sNcR4J5B3tToQoLr7wpk4EehqalpvpT1w84aZayWPzi5c/YD9bhKc?= =?us-ascii?Q?lHANl832kfDvjF/mpS/eCH+sj7LyLoDgok+zTjV0jQ2xZFTHNQK2HvXmkUda?= =?us-ascii?Q?8Pma/Ao7N+msxfmZmmVNcaFDfET5i+nIr5scRifVTLbB1n/aa7DPYpeMrY/w?= =?us-ascii?Q?dP0NDr0EEkLjcBSDBiwLe/c/fZeMrAg1cBZPRUeIiiSvsMuNiS+JCaK2+YOw?= =?us-ascii?Q?wfRggL/sOY6oy+wCQTNmDzJmn2rVLj7W733x9uV7g+G5bVLiW1vA0nY1ogW/?= =?us-ascii?Q?JUvm5jXHVaQD/OKDaxL6LsxEYxmZv0oktbCDleIQgj3eFNcmOj77TBcFOpjb?= =?us-ascii?Q?mAFyyBxmSrCFAvq1HKJ47Fy2pvaC2gSqeWi0DHLH0uroEld1BuK3630GJ+/O?= =?us-ascii?Q?uHhTSvRIi7AHXjlB3d7Vr90lP/Q9O0LF60QqZiZL4Sjs+HGkxtLNyLDgV6NT?= =?us-ascii?Q?4eA/mYzsZbabz7Q7NHsh8WQgxyxXc8a+MyulX5kmiapfmTROG7kAC4XUlmgc?= =?us-ascii?Q?fh6ST6nGEsa6ziv/ZGS028ue5oybPT070+Jd7n8nIV/aT68p+qwSlFWaJNoO?= =?us-ascii?Q?187t9Nic0cyWlLW/+bT85LhSpIHcydIyVPkygRMBs4n6eDmV8AqIw11vg+aa?= =?us-ascii?Q?IO2hoRUjWrdiWu46n/G4rdu3/fen8rFQ5NWV8HuF09tcnVnYXka82k3Z63aO?= =?us-ascii?Q?cfxgkiWDWSYDhJr7YJyRqoKcNE4PIuOVfgeiUwicCPVwMHaeglw0iphQrLuk?= =?us-ascii?Q?Ps2pCEVcjFBb3rKS6ifjQ1N866apyoeaRvCdaQyeQMOS1OutOziBf2q2gT2M?= =?us-ascii?Q?hkhWJoDvzxv5uBhc+yW8pnIuzBw9v5wx3JoJb2LHEtWiDe2PQ2GShtB811xe?= =?us-ascii?Q?PPlJ7swjWRXLOM1ZJbpuiPJyM1W2hwrfGD/km6xOvgHb11wpgIZVi+up87NP?= =?us-ascii?Q?EG22xl9bxsA6woIsgEbIWuUAb4EZ9zGUtjpCO4/QTklx2IbUOIAwr5d3bkfP?= =?us-ascii?Q?qbAxVW8MjoG0aZa199m6G0WBVQNoVOraFjDemOVR+nA2oGyp4UbPyUWlZA2E?= =?us-ascii?Q?lxByPpj7TMLxh4l6bkdOFZBQhk5WSeQisqnVwJzViun26vPHAlpov9EowGql?= =?us-ascii?Q?edY9Ct0TfiZGNdGULps8Xw1qaUBIjdQou/RykONI+y+Jin4TVVqZSeaOdfi4?= =?us-ascii?Q?tDF+mbCgt5vGxqxM2gGt33t6kWCe4D1hUlex+4ro558TdqFPWgSkyKlMhzBE?= =?us-ascii?Q?3ybnx9ZIdzKrcYr7jazdUGqJWCbnKAGemp2DbmS8tdZoNQiXb0+yodWYJFn9?= =?us-ascii?Q?+VROfHp11gJAr3Rrwm57NoLoKudOQ1Y8XHoVbjOZF30Sc2a/EdyPXlE/Vvkn?= =?us-ascii?Q?rMqxksparOc=3D?= X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:GV1PR08MB10521.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(1800799024)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-Transport-CrossTenantHeadersStamped: GV1PR08MB9915 X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: DB1PEPF000509F8.eurprd02.prod.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: 40082fdb-ee90-4e5d-fc78-08ddf69356fe X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|35042699022|1800799024|376014|7416014|36860700013|14060799003; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?WUCIVi3p2A1B0vCV/x0sCveAVbXq6I+QHknygJLjNhqkwaushLQqw5wOkQJ4?= =?us-ascii?Q?JPXVOsvYwGweZ6rOrspfIJG6jfiUT+5l/OzTEAbhjalOTtjl0dUBaCcvacAp?= =?us-ascii?Q?zuLrpgKmYrF0HjOH5V33mFzK9y60yeMNyvGIr5X9DfUcMmCbFzlCWBP6pVfq?= =?us-ascii?Q?9+9EohXdQ7rvPppiimDan1xhBgfcQ3Zto0yDEQTV48a9cQeAOE0nOvhFHj+T?= =?us-ascii?Q?fx4NvOPz2EIHwuIKnjpED63mD7twpJJiygsz4MB/e2NWX6SVjAGtPkoFaNlU?= =?us-ascii?Q?Edg27SZnxUp7QVbMohxglnVqmnvj0960ALS2IOtr22/gv9I5+DL9ONGjkb3a?= =?us-ascii?Q?ptQV9E82634yxComsG7AMyjDCBjZJh4WJILYGCgRw2A0Qfx6nk5JlYs2aiVV?= =?us-ascii?Q?9bJ1b2+y//h1WcUXqR/eIPqzy9v36XvvlY7edWtiwHmTzIKiVZwEWFrmLeCS?= =?us-ascii?Q?t6oHB2uUS+6PwyVWijL5cfR5VDe4+pQ9ULdXOkNGXYUGVeoA3qO2ZGhE2MZU?= =?us-ascii?Q?zOeTaES54scIw7fYa/63/w50mgxKjPWYygpmsEXkrINxmnV9PTa7khLu0aoj?= =?us-ascii?Q?p9VfCqrYGnsnrMOE/egQMfBp+RyrqmzaaIruDy98zAKp8+ltVmVpvyxCV5yF?= =?us-ascii?Q?REVpnWEzoCNaatEYeyW9zPclhDWmnXk26CpisDeRo5TlgYwW+uSWJ5TS7GUx?= =?us-ascii?Q?b5R5N0cnxuZGCm/RPzjvtoCEOBH851Grjy/3tygbqnv1XOE2Noel3QH+htBj?= =?us-ascii?Q?l9IJjMfJjcZ2kLAfGXjsQ5CM9QASxDJRWseby6SBKAnFGPMQZVTcCHRJOhJe?= =?us-ascii?Q?mzg/QE8JES361iVtokFRekILbKp1NS+WVRuPtcSQLV88UpUGN33nOs0z0rBu?= =?us-ascii?Q?SD2pMfTzwjr8pG86geEUcubMWZ93qxwW+p6plOwdIaRuS0YlDJeTJy79Phsv?= =?us-ascii?Q?h2WTGRimLyanIWGu4JilNsatUTDYCCIZjS+5U3lFSY7deOFPZ679rDS5N4Rd?= =?us-ascii?Q?j0SePU1j/HGyh49BlMqwEoDZvzJJTiBOeN5vyMrlijwZO8gTf+LTSUu+t0P8?= =?us-ascii?Q?Ii8WLUfiCwRpzmYChKHrrVtMQxK3k+G8sMrcWMVGYeDNEz5DhfeQoFpHCN+n?= =?us-ascii?Q?CDNVWjmbjcymKbK+lZDD46zymSG4dO3c03WdvOB7L5eqa7ZJ2J3Utg2qbAkP?= =?us-ascii?Q?qNuDwnMpBOPOJ0YQkeHQG6vw+9o0k1gKRzJqLPVkSW/g2XmDK1p1p9/ZHh0K?= =?us-ascii?Q?en3jLuM5rotUg/hDmp7Qjx2JDwPIFm6yJkPx2/qhS91Hm7T5v3CzAhkDlLhm?= =?us-ascii?Q?w2orCbFYacMQzP9hRA8QH+uMi5s9hAigirS2a16LG6SPJiJNfU5pI77969Wt?= =?us-ascii?Q?Y0HSQjhSfJqDexUulvF0j6tAxZHTnI3sEtOZMwqoAYSvwD6nlzqwY1UUyGd8?= =?us-ascii?Q?lT+Fnsn+CeTNO/cPpUvczJWwzDkzDkl3u8VJW7CkoyONZn4oba7rUi7bH9Yq?= =?us-ascii?Q?NUuNkgaMdd7F/dJiLbHJ9mdzB1v5t5QwaUrc?= X-Forefront-Antispam-Report: CIP:4.158.2.129;CTRY:GB;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:outbound-uk1.az.dlp.m.darktrace.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(35042699022)(1800799024)(376014)(7416014)(36860700013)(14060799003);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Sep 2025 09:11:59.0721 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 9221b7f0-a43f-4a57-67e1-08ddf6936c2a X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: DB1PEPF000509F8.eurprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR08MB5488 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250918_021209_210406_95CAE20D X-CRM114-Status: GOOD ( 16.62 ) 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 Hi Mark, [...] > > > + static const u64 hi_mask = IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? > > > + GENMASK_U64(63, 32): GENMASK_U64(31, 0); > > > + static const u8 hi_shift = IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? 32 : 0; > > > + static const u8 lo_shift = IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? 0 : 32; > > > + > > > + uaddr_al = (u64 __user *) PTR_ALIGN_DOWN(uaddr, sizeof(u64)); > > > + if (get_user(oval64, uaddr_al)) > > > + return -EFAULT; > > > + > > > + if ((u32 __user *)uaddr_al != uaddr) { > > > + nval64 = ((oval64 & ~hi_mask) | ((u64)newval << hi_shift)); > > > + oval64 = ((oval64 & ~hi_mask) | ((u64)oldval << hi_shift)); > > > + } else { > > > + nval64 = ((oval64 & hi_mask) | ((u64)newval << lo_shift)); > > > + oval64 = ((oval64 & hi_mask) | ((u64)oldval << lo_shift)); > > > + } > > > + > > > + tmp = oval64; > > > + > > > + if (__lsui_cmpxchg64(uaddr_al, &oval64, nval64)) > > > + return -EFAULT; > > > + > > > + if (tmp != oval64) > > > + return -EAGAIN; > > > > This means that we'll immediately return -EAGAIN upon a spurious failure > > (where the adjacent 4 bytes have changed), whereas the LL/SC ops would > > retry FUTEX_MAX_LOOPS before returning -EGAIN. > > > > I suspect we want to retry here (or in the immediate caller). > > Right. I've thought about it but at the time of writing, > I return -EAGAIN immediately. Let's wait for other people's comments. When I get step back, I found my thougt was wrong as you point out. So, what about this? static __always_inline int __lsui_cmpxchg32(u32 __user *uaddr, u32 oldval, u32 newval, u32 *oval) { u64 __user *uaddr64; bool futex_on_lo; int ret = -EAGAIN, i; u32 other, orig_other; union { struct futex_on_lo { u32 val; u32 other; } lo_futex; struct futex_on_hi { u32 other; u32 val; } hi_futex; u64 raw; } oval64, orig64, nval64; uaddr64 = (u64 __user *) PTR_ALIGN_DOWN(uaddr, sizeof(u64)); futex_on_lo = (IS_ALIGNED((unsigned long)uaddr, sizeof(u64)) == IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN)); for (i = 0; i < FUTEX_MAX_LOOPS; i++) { if (get_user(oval64.raw, uaddr64)) return -EFAULT; nval64.raw = oval64.raw; if (futex_on_lo) { oval64.lo_futex.val = oldval; nval64.lo_futex.val = newval; } else { oval64.hi_futex.val = oldval; nval64.hi_futex.val = newval; } orig64.raw = oval64.raw; if (__lsui_cmpxchg64(uaddr64, &oval64.raw, nval64.raw)) return -EFAULT; if (futex_on_lo) { oldval = oval64.lo_futex.val; other = oval64.lo_futex.other; orig_other = orig64.lo_futex.other; } else { oldval = oval64.hi_futex.val; other = oval64.hi_futex.other; orig_other = orig64.hi_futex.other; } if (other == orig_other) { ret = 0; break; } } if (!ret) *oval = oldval; return ret; } Unfortunately, if there was high competition on "other" I think return -EAGAIN is the best efforts.. Am I missing something? Thanks. -- Sincerely, Yeoreum Yun