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 388C6D2ED0F for ; Tue, 20 Jan 2026 10:09:08 +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=oNmrwiIbxYygLUlVl4JfPOzhtIrsHlj6sMYBfsXTjHY=; b=d0f5ZGkOnrFOnEB/hR0xnQFTN7 tKPOFsyvycl74rJ+fyadoCKUGDhT+vSDQUZeulI4K378ZRtuAll6pLbGbCFmFotLK/flzWfU+QTmU Y5oYnQdbZ83eTHMZ7yFUZaiqc6brXB7P6SJoskJwuRo8am4MXtkGdnYEkDEegWLpFrUbFMcQOkm1b 6gG3p3D2Ke6F7WErsc8/RlgD23LRP5iCRTeWSl75X5s/zOfxv0pDWALRJUghPs5BA1dR/KrOxh9DX zU8CnDlBBM5TNvY0sAE/XgftDDEL8BxeepDkKAT3xCcpoEbTOS45DilP0vyifcBO6MN22I0aIw1+q 4o7f1SRg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vi8fT-00000003ZzZ-1gqm; Tue, 20 Jan 2026 10:08:59 +0000 Received: from mail-swedencentralazlp170130007.outbound.protection.outlook.com ([2a01:111:f403:c202::7] helo=GVXPR05CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vi8fQ-00000003ZwQ-1Fof for linux-arm-kernel@lists.infradead.org; Tue, 20 Jan 2026 10:08:57 +0000 ARC-Seal: i=2; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=pass; b=xxJWZlcTplBHKwptXWwp+wzfDIZ5/lWl5OfDYjR84ISjo5mbK2iDBmIOWdD22XOmUvszmkANO2urB7CHYKorZm906hNa1BLmR1ZnmdLOUpWrWMjMIdE18/A2pwFOLU0X+FFgdTmQYbUxlW4YWm3WMwfMHAgQT46Q/PWva48mGaSJGWsLtc1K8VZpfw+JsJ0zbTBaf6ieM6fV8i4DsB8ppSUNoB66K/ERlGTXyjBeazhqYWH7SO2epCglnNfdYz6P9zJ96TjOXX1loax2HMtkm01d9ZkQXk0FDZZwPwpbSo2ef/QRbYvBhcnAx6cUkAIyQCKAevyMGu+E6QF0spH5jg== 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=oNmrwiIbxYygLUlVl4JfPOzhtIrsHlj6sMYBfsXTjHY=; b=vzmg3brOUsIBiCM81BTVlJR4JxrkukHhTHgUdIyCOiMcru1QazpoYfEhE+38HZuc6HvH6igZA5a4rR+Q3wddc6lL+Wa2X7hQRwIMHDjaTT9pJsxFxiUaI6SW0Y7TVopDdaU5WnLGYJi/2OplLTSHYB+nNMFFNq0v07/4TcuKUqJivM158nco7eY1Edpap67+h13ghGnwSseFu5UX/K3fMHpurqCkcyFOP8wMdzoXwLEHQW2YD22NLDGDH4WdVOEgRKe/2EuBRg3zqskMsgZKFJA2ySmQ6BRECB8tJwmcA/d1W9EMxGWrriNYKH8FkLmRPYLX6z77fDoBSXFLv9EDnQ== 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=oNmrwiIbxYygLUlVl4JfPOzhtIrsHlj6sMYBfsXTjHY=; b=HSdJ8YlqiOvD5aYC72Hk/PIaIleMRv+IJkUUK2TE993nm3VVzdD/mx+8G7npI95PeKOdcRb46ihFSi7EHqA5389rCt1Tfd2YlEyM1z07dgdt9+eaB+ECd3rA0rZn0WpCu++4d+LAdxuHpQo5JZ3WEMYwFcgKl2Jxw/Jt2/4pIxU= Received: from CWLP123CA0241.GBRP123.PROD.OUTLOOK.COM (2603:10a6:400:19e::8) by PAWPR08MB8912.eurprd08.prod.outlook.com (2603:10a6:102:33d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9520.12; Tue, 20 Jan 2026 10:08:44 +0000 Received: from AMS1EPF00000040.eurprd04.prod.outlook.com (2603:10a6:400:19e:cafe::1c) by CWLP123CA0241.outlook.office365.com (2603:10a6:400:19e::8) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9520.13 via Frontend Transport; Tue, 20 Jan 2026 10:08:02 +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 AMS1EPF00000040.mail.protection.outlook.com (10.167.16.37) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9542.4 via Frontend Transport; Tue, 20 Jan 2026 10:08:42 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=dU0mMUdMVm1HP2yexkjE58iZse6gTVHlSU2cf5DvArsItHRgHeQlSevDUhmq323EA+nMDKvzFdmQZqxVhxfM8AOkvUw3YL9RBym3yMR8YBptOJUTf0NaMLcJHD/4HPLFlU2nmgh1i1J//5xQLWjtTho2giQoM6amZBGsSNCrTGBZrTw5On0ru6i7hE6jMjrmOe0PCMdRMH1vV0arW7zkdwDQ9E3PoTdIEwY+DL5yDruaoUn7G6Rz+o4Y4UVnAUS9N+Z9ZRH1yIl83PMZqYxGmVoG77bmPOFgJhUPmiFUGqKWNdIg9WQIYS7fCTmOTT0Qdi2qb/cBnLix2/8KRPAdCw== 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=oNmrwiIbxYygLUlVl4JfPOzhtIrsHlj6sMYBfsXTjHY=; b=MJg1N0bd8w4/THDi7Rd1Euv4Se/3ObX/SY905Uy6yRszj1iXDaD7NjznpZbEFDjS2D/X6r9K6q3n++4qAtZepEq325tRo9mDnmy9m+kc4t6MAseqQrqZuytLVBPDzbSiNzncoGhU4IK/YP24z/7VoIauF20qiACZPVMTL1/mZUa1Fcy6h02gpHglhvil1tzqGEx/Nl/3Z3DY2eIovJ+PCVNooZigDS5u4C6Oh6Hy3dsVm7ps1+FDBuhXxPYcVVgVKr2vRuorzl6i8g+PPTRzk15Ny2s6Fm3q+6PCfOenCE8cHGRYtH6lkWuLg+B3kVsQRPsgXP6hacd1agsfKGQTyg== 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=oNmrwiIbxYygLUlVl4JfPOzhtIrsHlj6sMYBfsXTjHY=; b=HSdJ8YlqiOvD5aYC72Hk/PIaIleMRv+IJkUUK2TE993nm3VVzdD/mx+8G7npI95PeKOdcRb46ihFSi7EHqA5389rCt1Tfd2YlEyM1z07dgdt9+eaB+ECd3rA0rZn0WpCu++4d+LAdxuHpQo5JZ3WEMYwFcgKl2Jxw/Jt2/4pIxU= 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 GV1PR08MB11090.eurprd08.prod.outlook.com (2603:10a6:150:1ed::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9520.6; Tue, 20 Jan 2026 10:07:37 +0000 Received: from GV1PR08MB10521.eurprd08.prod.outlook.com ([fe80::8c9b:58d2:2080:eb98]) by GV1PR08MB10521.eurprd08.prod.outlook.com ([fe80::8c9b:58d2:2080:eb98%3]) with mapi id 15.20.9520.011; Tue, 20 Jan 2026 10:07:37 +0000 Date: Tue, 20 Jan 2026 10:07:33 +0000 From: Yeoreum Yun To: Mark Rutland Cc: Will Deacon , Marc Zyngier , catalin.marinas@arm.com, broonie@kernel.org, oliver.upton@linux.dev, miko.lenczewski@arm.com, kevin.brodsky@arm.com, ardb@kernel.org, suzuki.poulose@arm.com, lpieralisi@kernel.org, yangyicong@hisilicon.com, scott@os.amperecomputing.com, joey.gouly@arm.com, yuzenghui@huawei.com, pbonzini@redhat.com, shuah@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v11 RESEND 9/9] arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation. Message-ID: References: <20251214112248.901769-1-yeoreum.yun@arm.com> <20251214112248.901769-10-yeoreum.yun@arm.com> <86ms3knl6s.wl-maz@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: LO4P123CA0339.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:18c::20) To GV1PR08MB10521.eurprd08.prod.outlook.com (2603:10a6:150:163::20) MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: GV1PR08MB10521:EE_|GV1PR08MB11090:EE_|AMS1EPF00000040:EE_|PAWPR08MB8912:EE_ X-MS-Office365-Filtering-Correlation-Id: d7f62c08-6d92-49d1-3a5c-08de580be429 x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0;ARA:13230040|7416014|1800799024|366016|376014; X-Microsoft-Antispam-Message-Info-Original: =?us-ascii?Q?ywzuM6qsfrvVMhUEnIuXJlzhzJLgSVbubm4dhkm3czGz9CnvO5MOJYbfVAdz?= =?us-ascii?Q?qKdz6hKNyGVZYj1UBw62doZZrWS3obYp7beo0OZLDacWzZWTi3EYrSK2SxNF?= =?us-ascii?Q?4uco8xpQHPtUDflRETeXWHV5fST85TJQZCa1y7j5qJzVHssptdz61GvSeggc?= =?us-ascii?Q?gXruwMtFVr9wc4DDOWD+9lXRZ3NcjzXIAChMA6lwEtdhzVcrhxraINFRQmCx?= =?us-ascii?Q?GDrHU4Bq3v2Ug2LvTcXJfMz2n8b9JBC2HH8+p2Qj1XLpdtyEKzaoCYcrcxls?= =?us-ascii?Q?Ybvrii3pQDajkG7k9ez9JiD9YfWmcK7gu+PpwCPS4/AF5byPSezk8wzAKWg6?= =?us-ascii?Q?bsN3ONPSTxhQXg8VikYGDnsK3zmjO2b5u6K0kdAFHEfDou47CId8UE0nwam5?= =?us-ascii?Q?KFZUTZuQ6VlDMK7DTR8i/lMwDRLoi0043viSwbOchEh3CloUWZyD7rAwZ9Hz?= =?us-ascii?Q?pGs/J7IrymMYTDfQP4HXKyr+suXAIyKScw+LdS/1EQM2iqr5OKx4hQTHUF8I?= =?us-ascii?Q?ac8zkLxogHCjGQtC6m2N2zzBmaiCubsqZMHVBQMsru2+QaXYRxrtxHKfzTwk?= =?us-ascii?Q?ykWdPCkGr/aNci52ZXpQqQlWd0U0ObL8IS8/eG2IMv9XLFO8A748IRY7HfCd?= =?us-ascii?Q?aBROGzZRdf1LGP86bV+9hZKE0tcYYY+42E1UqspGNFDDvPsuY67bKOteraAC?= =?us-ascii?Q?8w7K9266hquBhSyN6m3St5IXZlrpNxwEwhNqPVWD0PGpFKODZer9nZMZtrAX?= =?us-ascii?Q?D2FtPi/rQV0/48iAI0nMYZoRc4WxJUvxZjjEuM+cGU3ov5ET3FshticNvVD3?= =?us-ascii?Q?i4ODdr7vb1/kmdnkLzYvgOLbzdVVl7UpcBywDvHvp8C+R9nsMNUliiGA+us6?= =?us-ascii?Q?DeG+c2hMym3+kmsAiI/RYTWOQ5Kk7VNJpfqixwdtSIvZQo3zvy9D3EJLQsqt?= =?us-ascii?Q?GsXzvHLlXVoRIK3LuZEw4BoE/ccImbAZCFI22YCyyXLYrsQSI2eO6PS7xUt+?= =?us-ascii?Q?XX8DJLr7MY+0sqUyz7kyb8GKafXTZ/R2elKMQ5Cu4opmPZKHC5RcBXw6Rmlc?= =?us-ascii?Q?qw8hhmS0lMemOEFlS+fTUmc3kiRwdbvURakWGThPV4UMbxUTItA4qdEZlcQ2?= =?us-ascii?Q?Bxm/q982qLPytj/VzrKom3lBpIZsXVhRY3Xr1ZgjVEL/2Zl/GqtU8ZF9aPXB?= =?us-ascii?Q?CENkz7if1oMMPb97dY8SLh9ScpwvC4/UpEeACP80caF/rE6iLk/yeRF1GGOe?= =?us-ascii?Q?CYomHosxsrxAPcMNZP30ahenh/465yCO6xZD5Uz5+r/vOhwCJ6Vba47eBA5S?= =?us-ascii?Q?JOuIhih7HzShe6ch7HU9TCMAKz8v0KtH3E79ZT9Saitc4PIqZ84GgV10+ldd?= =?us-ascii?Q?QA+PSLtS0AEkIhFjl5VUAWjG0Ae2T/40K/S9CzrSLE0tyWywUhXwfCsRMizJ?= =?us-ascii?Q?onIkRIjztKctge00WA5gtzvsaHkyeG50I5NJoLXKlsL0FdpeYS77vehPPgO7?= =?us-ascii?Q?FlQvS7KteL4uf3TNx3VpbsFnnnqfLS1K804N61k0VLGhr6+N+McDZVGrtrJH?= =?us-ascii?Q?Qi0wQKzlV3ved6ht8DE=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)(7416014)(1800799024)(366016)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-Transport-CrossTenantHeadersStamped: GV1PR08MB11090 X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: AMS1EPF00000040.eurprd04.prod.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: 17b70958-4515-4769-60a6-08de580bbcc3 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|35042699022|376014|36860700013|1800799024|82310400026|14060799003; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?UPvHsXwlg7dpBjCHP/wZ86rNyJHm4AP51oMacXeAvbUuI32MC9nOmu5E5QzB?= =?us-ascii?Q?e10jitBwdF48qFjc8Y9naYRzysli4PkSvS7DqltSCPWo7V5KHncGgiOmnNEp?= =?us-ascii?Q?uzycAdrO6XrYKiLUXZ6mgA3+VJzXbB2+fkHmKXlr5xgqc6PzJsEEGJ8nKA6c?= =?us-ascii?Q?xszpV+yYIwzJrB3W3bRX58RukooSvgSX2PWxPIJv8tIrsY5YhvxXK7Aot70b?= =?us-ascii?Q?PAkBO8PaN1Fdkd13KJ+CkFE9+1rfm5NNe+S0xLR511wnYjpgQ6mvCFvS1NhA?= =?us-ascii?Q?4yjMo0J+9JN+mgXLxxfI2OX4IjUFl2obx3LAeyqktEdLh9d/13AbbvFAj6UV?= =?us-ascii?Q?kKalSfbgyH7qYxtygkqtlkxmfQniXgdetJvwtDHvErNfgdV2ObKOO/zQLqJR?= =?us-ascii?Q?E7yi/QN3BQQ+SxLdst/ZayEM7PIS2D1iPosDof/PZ2rpGuF8rbMH8yQjrg2L?= =?us-ascii?Q?ut80Kyf5wzqX5ZyAg1I4k4QfbKktTD2bi+2HjzwiMR3zRnYWU39CqAxkOkKn?= =?us-ascii?Q?7pE27CbJWtdisY5/3ln3/5dLgzQsH2dQ3Y2pGr0sH0dX2A3Zingd4B/PDohH?= =?us-ascii?Q?zFx30zBf+Gm107fQdV1DZC0fZLxGHFMXFDwUqTNDuM1IUfbwxcupNSr8qqsX?= =?us-ascii?Q?TytUtfIB82OKt+ScGCREdNM7cnzlFKBNYpHKLqPDK31moGOSNb6cYkXYE7ge?= =?us-ascii?Q?t3UB0VvzmDf9gdd8sAwBxMHWgwBWISbX9mUZSaP75NjfdPn94GTvj7y8H69D?= =?us-ascii?Q?C6agVCS2qOPtm8IWIv2oBQ6hLlxmbAAoRqLjHYTv6bKQg4j+jHjIAGPMYWbV?= =?us-ascii?Q?Zsql4xvnOazjZ2NgTJfmNcx3UnufJs8NEMmbxeE/Csu9sNBZmyjjPHU7kWbE?= =?us-ascii?Q?o2mcXhtnuh3mKkqnfXH5Yjno0H4Y6z+ujsvBcteb1ixtWFcFeLXUlHpnTIXN?= =?us-ascii?Q?MmoZUv4FrHE98iGpF1rzi5fYsy07CYzWNBJQA2jRpOsX7H/588OCk5iouSp0?= =?us-ascii?Q?6M4OBw9BOzJafza1Rbj1vrMHZHvfHpk/5gZ6XT1ADUchbg+njpfRjaipMkRz?= =?us-ascii?Q?yR9HMb2/ZCDwNFroPEXccrFHXFogDW/QlJZ3FpLtzY4S73LVO2R9mIIBv3NN?= =?us-ascii?Q?f4PXzgz5DYQzUCexGgRm/v3gjQ45x6SOYVy9Y4VfpqjS6Q2iws2GXpg7rqjg?= =?us-ascii?Q?GZi4HZCNIiLl9WlfoVh+/9CAdDy7K75CdRvE4Oagza49Uf05yFfSXfjPEZTw?= =?us-ascii?Q?BANToYVGFylxi+lNX3vLo2MLyln1FBGVeJ6oKr4OoCxj86lXDa1ld3ZDPFQs?= =?us-ascii?Q?tD1WWmIp4+5jWJGQVEycTlLOatH/eABhn/OVTeChqxWAfOXVBL2MV0JC+eIR?= =?us-ascii?Q?vMKTrEy5PvQ0tJ5lomzTZIlCdkHf5K7mn0hmJTZ9LX/ntUm+Ml3HqvViM1g8?= =?us-ascii?Q?QfiqpM5nY2+yjmhQBxlLEGXdvEwWsvFxdjGphzmd5nQNPR2ReH7+XWXkRQBQ?= =?us-ascii?Q?A9y/uYUL43P92M4vT/CKCDVsbyHf6kD5S5zUpz3e4NgI7VEFGNyogynQr07S?= =?us-ascii?Q?omqNtLctG67AXvdLSYzDU3EKeymes2dsFxjzY0iJgH8cY9J2s78tQedc8zae?= =?us-ascii?Q?p0v72zzwGT2DwyMklfgiowh0OEIawebM1iTrJcmZzk4SRF/QtH0USZf2zvX7?= =?us-ascii?Q?juMebA=3D=3D?= 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)(7416014)(35042699022)(376014)(36860700013)(1800799024)(82310400026)(14060799003);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Jan 2026 10:08:42.8100 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: d7f62c08-6d92-49d1-3a5c-08de580be429 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: AMS1EPF00000040.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAWPR08MB8912 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260120_020856_510070_9300B90D X-CRM114-Status: GOOD ( 30.29 ) 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, > On Mon, Jan 19, 2026 at 10:32:11PM +0000, Yeoreum Yun wrote: > > > On Mon, Dec 15, 2025 at 09:56:04AM +0000, Yeoreum Yun wrote: > > > > > On Sun, 14 Dec 2025 11:22:48 +0000, > > > > > Yeoreum Yun wrote: > > > > > > > > > > > > Apply the FEAT_LSUI instruction to emulate the deprecated swpX > > > > > > instruction, so that toggling of the PSTATE.PAN bit can be removed when > > > > > > LSUI-related instructions are used. > > > > > > > > > > > > Signed-off-by: Yeoreum Yun > > > > > > > > > > It really begs the question: what are the odds of ever seeing a CPU > > > > > that implements both LSUI and AArch32? > > > > > > > > > > This seems extremely unlikely to me. > > > > > > > > Well, I'm not sure how many CPU will have > > > > both ID_AA64PFR0_EL1.EL0 bit as 0b0010 and FEAT_LSUI > > > > (except FVP currently) -- at least the CPU what I saw, > > > > most of them set ID_AA64PFR0_EL1.EL0 as 0b0010. > > > > > > Just to make sure I understand you, you're saying that you have seen > > > a real CPU that implements both 32-bit EL0 *and* FEAT_LSUI? > > > > > > > If you this seems useless, I don't have any strong comments > > > > whether drop patches related to deprecated swp instruction parts > > > > (patch 8-9 only) or not. > > > > (But, I hope to pass this decision to maintaining perspective...) > > > > > > I think it depends on whether or not the hardware exists. Marc thinks > > > that it's extremely unlikely whereas you appear to have seen some (but > > > please confirm). > > > > What I meant was not a 32-bit CPU with LSUI, but a CPU that supports > > 32-bit EL0 compatibility (i.e. ID_AA64PFR0_EL1.EL0 = 0b0010). > > My point was that if CPUs implementing LSUI do appear, most of them will likely > > continue to support the existing 32-bit EL0 compatibility that > > the majority of current CPUs already have. > > That doesn't really answer Will's question. Will asked: > > Just to make sure I understand you, you're saying that you have seen a > real CPU that implements both 32-bit EL0 *and* FEAT_LSUI? > > IIUC you have NOT seen any specific real CPU that supports this, and you > have been testing on an FVP AEM model (which can be configured to > support this combination of features). Can you please confirm? > > I don't beleive it's likely that we'll see hardware that supports > both FEAT_LSUI and AArch32 (at EL0). Yes. I've tested in FVP model. and the latest of my reply said I confirmed that Marc's and your view was right. Thanks. -- Sincerely, Yeoreum Yun