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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5670FCF6BF4 for ; Wed, 7 Jan 2026 07:37:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BB8E96B0096; Wed, 7 Jan 2026 02:37:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B789A6B0099; Wed, 7 Jan 2026 02:37:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A102D6B009B; Wed, 7 Jan 2026 02:37:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 8D2326B0096 for ; Wed, 7 Jan 2026 02:37:57 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 44F521ABBC for ; Wed, 7 Jan 2026 07:37:57 +0000 (UTC) X-FDA: 84304363794.06.9C7D8BF Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf29.hostedemail.com (Postfix) with ESMTP id E7813120004 for ; Wed, 7 Jan 2026 07:37:53 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=nagjkpGW; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=qfdG769w; spf=pass (imf29.hostedemail.com: domain of ankur.a.arora@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767771474; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=CcI7O2ifmp8h+hzDaZkOiO220BBOBv7DEpClU/C09cw=; b=ADuwhKc4FwoWmm7byDkTxcpzKJc0MhFVuh7zOqdsO7R+RRwJZC6hldq6waFrmSKofgpiCd /KKWzqQlwjBw++Qsh4ARWSyalsOEiNWn9JBhQDsLMkb+mtRGJ+iI8yfm55tptqHON+Ova7 //O+44i8eFqYSQm/W1/eB4xAXCuRPAg= ARC-Authentication-Results: i=2; imf29.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=nagjkpGW; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=qfdG769w; spf=pass (imf29.hostedemail.com: domain of ankur.a.arora@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=ankur.a.arora@oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); dmarc=pass (policy=reject) header.from=oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1767771474; a=rsa-sha256; cv=pass; b=pdjaAZuvvnBvNLXxf6T/5f5HM9WSLXJr8CyrAg0MH3v3m8IgJSY2WZ2a8wEJHOqMnRCf9U ae30tNfNGJPg4Gm5fdxBIUxG3cORH5dWa0bR7UTZdDyTdAkGIWoff7zcB1O5ChEnU2SWQH wo3pOmLFSEDuGQb6Os9ZzhGSYJ8X0ig= Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6076Kuo51431714; Wed, 7 Jan 2026 07:37:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=CcI7O2ifmp8h+hzDaZkOiO220BBOBv7DEpClU/C09cw=; b= nagjkpGWGpXuoTu0kwYM8xblp+CGkMllGJj8piI+OAv7wcQz0ZaeD1srL6Nl9K6i QPDLuJQ1Dfxhqn/fWqmYv/QPZ55ehBYZQRNdupTGAG3jZyBgIvhJii9+CVfKXxN0 tjc0DYXxkQjMGJg+voZcW5QQalR1+55FLOq4O2TC2Q0y4+r/oLtG7H/3gBTnZvZB LXdmcV1D4mmGw6K2rYPQOM/w2x16hPtaZOvSqIFiGBup2k0y9lRDtL+8YEV3+6dF e0emMleokejOuSNw4L1Me0o9UxRHRKmvwE8Z4lwPRIBJtGKG0BkNqrBoJhrdkf/y GoF2ZImn69Nnk2au6RV2Lw== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4bhj4ug1wd-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 07 Jan 2026 07:37:25 +0000 (GMT) Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 6076txVG020387; Wed, 7 Jan 2026 07:20:29 GMT Received: from bn1pr04cu002.outbound.protection.outlook.com (mail-eastus2azon11010032.outbound.protection.outlook.com [52.101.56.32]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4besjkhwjh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 07 Jan 2026 07:20:29 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=k3lX1cdVmrQ1FSEiy0yPqS9JHne949AnJ0i+kpgKpV1KI+VtEXa+2e3M91zGBDo6DC+PeBzLMKubbWCBnf2tO/fEpVe/hCVb1mSMYXMHhL1yzoqf6mEhNE8YRRv+kUuLt+6DPTqemdwybwL0HjRrlAcTu2WdpXtmNepQGrcgfIbjSefBlblNA5T7d0RsYBXR+Z7SbtKpqKTZEZBWKSQ79ktV6y0FUuMCRHU0FKbvYAUHz2++0Og0I7QdwBUxYGJ7GgdM6F1ED7tDRTepSmm2kamW5gotu/5Hy2FJBsCQAA6HpkJKUghiyhyW477AmuTpxakcJPntxh7xw+AROszqxQ== 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=CcI7O2ifmp8h+hzDaZkOiO220BBOBv7DEpClU/C09cw=; b=NxCeGvMuxfGGJG6ZZNH0EpsFqmLApupTKRzAM/X1TS+gO64F7QYdozaar2/ftPZHbTtcw1YK1MYkfgkGtw0FukO1sY7V76JNHPhLLraDguA0qXv9PQLlcQElv7U+pyuTigKCVcWaMThynRJCe2oY5do63nDXqnjarrsS/scxEZhlFU1nXer5Mn7i4hc6ctKT7Y6E6CXkqEbWeB1xV4ZmK2Pnz8mx56UmRhC6i2KQNsd4O6WbMVRjX+n+TKk9oX+Nn1VRn4sE9Y7pVBko5xqBak0kaW7OIeJginMWUe9+dOdElYCQZuwwni7/xI2++64bRKXv8OdVgJ4hdgTfJySHcA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=CcI7O2ifmp8h+hzDaZkOiO220BBOBv7DEpClU/C09cw=; b=qfdG769wi/B+HDt6Y8mZvOaCGAs3p4bu4pU0c8/vP+7qXJ9uN8H0DRokG5dHGGMmUaJeX0Z04F5dcmfwvTHwGf5T/H44LyH7Je9h/x3Q+0mjBEnWdj7zGUD0szydCqlSA/x5HDXDyvKmNbAo0e1z3+B/j6oxsDnBQHGTiY0113Q= Received: from CO6PR10MB5409.namprd10.prod.outlook.com (2603:10b6:5:357::14) by LV8PR10MB7750.namprd10.prod.outlook.com (2603:10b6:408:1ed::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9499.2; Wed, 7 Jan 2026 07:20:21 +0000 Received: from CO6PR10MB5409.namprd10.prod.outlook.com ([fe80::3c92:21f3:96a:b574]) by CO6PR10MB5409.namprd10.prod.outlook.com ([fe80::3c92:21f3:96a:b574%4]) with mapi id 15.20.9478.004; Wed, 7 Jan 2026 07:20:21 +0000 From: Ankur Arora To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Cc: akpm@linux-foundation.org, david@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, mjguzik@gmail.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, willy@infradead.org, raghavendra.kt@amd.com, chleroy@kernel.org, ioworker0@gmail.com, lizhe.67@bytedance.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, ankur.a.arora@oracle.com Subject: [PATCH v11 4/8] x86/mm: Simplify clear_page_* Date: Tue, 6 Jan 2026 23:20:05 -0800 Message-Id: <20260107072009.1615991-5-ankur.a.arora@oracle.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20260107072009.1615991-1-ankur.a.arora@oracle.com> References: <20260107072009.1615991-1-ankur.a.arora@oracle.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: MW4P223CA0023.NAMP223.PROD.OUTLOOK.COM (2603:10b6:303:80::28) To CO6PR10MB5409.namprd10.prod.outlook.com (2603:10b6:5:357::14) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO6PR10MB5409:EE_|LV8PR10MB7750:EE_ X-MS-Office365-Filtering-Correlation-Id: e66d36c1-6ec0-4ed0-07fe-08de4dbd37aa X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?w59zlx0ZlEQAnCG4qY9FMU/Phig+Ojw/Hgi1KV5VeFWNFludkkTJvc858LN8?= =?us-ascii?Q?FggqrNDNpMxGYDyKvq0cRUOMMx6AP0lBrUlRHeZSQ8la7YA/bdbCmYD/9Fcs?= =?us-ascii?Q?DhMiMSEEUQ5a5tg8z398KVLD9/upxttPypt+kKvGRJg+CrsIL3bckCy9Zw57?= =?us-ascii?Q?MTq4pBA6Lx7a2umM4WS1ZNNxkszYswLhBDB7TeT7cjqb0IKeKq8n8Rj0PnxM?= =?us-ascii?Q?KfcbzIRljIktkBc4VapLOYUNSNmVmeMAh4nvik6Lnrd6M9U3ZnSsv/Fq3I06?= =?us-ascii?Q?f9XXG6tl/adPXi3zDpDlCn24YmQkjEMsX9ARuRTFaUtgRJS6z740i/ZPM36w?= =?us-ascii?Q?IMKsDIr75UBrKpmj2GmUa5QRyt85RAr0i83SN/6IhTpJbVCbvrNLAveAucNd?= =?us-ascii?Q?X8vVfD/4gjvDIW2XpWovn1ZndpNEBaICcEqDthG5WqwtHT54/pGOTSyOWw66?= =?us-ascii?Q?+E+vb7X8UbviziJZyocdcyaXCLFbNMZ0trRF67YZTzPPyYrFZshTyqq9w5Zs?= =?us-ascii?Q?oKrltClqP2gq6j/+tnOkhnxCsiyjJxL1WB7Kkr2I+8NsPrvjFjGnDNqWIDZk?= =?us-ascii?Q?QlBIkCzKCojH11nsrTFWEI1Pq47lWmT/rIUAnfbD7wn6TA6Niwzulm17svf0?= =?us-ascii?Q?wHc/9O4YpjhOlvJsLq5dfXu8gBs/abM//CRtksypJiRoDhgIoh4pidkJ6Teo?= =?us-ascii?Q?0iiOk2zd+4I6x4g1K/LgibooO3yPIicX33IgPkteL+0swfvCdjnybjLzOaik?= =?us-ascii?Q?sqGOFMLftrNm6dn0kl4WD+YPlPLYOfjq0Jye61WmJjHLhvQFhKzR8Lr+eVwl?= =?us-ascii?Q?cSC51ia7RPC3Po13gvHErgUY6jdNPb7BbqE56vMG4b8Yg/k4cvseVdDoQoTx?= =?us-ascii?Q?+Zk7J5apLGF9OaAwG9qna3mj5WvqufPnIrKuyAPIZ/CZk/R0g1OMQRSA5+in?= =?us-ascii?Q?oWwdY672ljoQ5WR0nBZIrEl5RLhlZBEzbL158nGyXOGJxBR/0HnnrX/hu8ic?= =?us-ascii?Q?STX+4iY8m11GnxO8Dsezvi/JRmj674OTDSBV67FHl027H7jxD5oU55Fhyd4e?= =?us-ascii?Q?94HKcTqfZUxPKFeuiyvMw3K8DDpEOkzZQdFJiRmxAaTWA9AfVjhlQ1EH/Sy/?= =?us-ascii?Q?QrjPvJJ5/tulDVoh4+4go3RnrcoBfYK1ttN5RVq1Hy+IK6gUNzls4SXc6AnJ?= =?us-ascii?Q?4uzHE/BlZLBkEahCrRukq7wDW0r4Z1e/H3TL3QHyOV7sRwI1R+WrfIcRVrsv?= =?us-ascii?Q?pir3hmKdULFOXsjFD59V843BR5uRj16NNLYu+kou7xX26DE1Qcq5/uev0ArJ?= =?us-ascii?Q?l2kjzg/SB7IeHhv6O0+fqVeltfDzhQx61cKUUih4TzYcf5X1hsiQ55CKo+O9?= =?us-ascii?Q?a2YQNEhZyG93QnURHbGIE3vtcCpC3wi5EWuAnPLAjGNo661QW4S9KaIzrfHK?= =?us-ascii?Q?HTLfndfCPkK894rMWLdaXeMZD1qv5MVE?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CO6PR10MB5409.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?OcUEo/umY4d8uhFH4oo5q2I0OEAC/24kg34M1mfoABz6W9Ngz72Asd43dWXZ?= =?us-ascii?Q?KpEm2tMaTkJ1XslM9NXh1B8yrsMJFGQAMBHr2VXtlSHx2OS1ehBTBuTMMRka?= =?us-ascii?Q?WUSbZhLtNmcO8RWEXSKqdg1s63hIgAnsLe6/JkDtB9+1GF0sgxiIFEy17iem?= =?us-ascii?Q?yflJfI4bvaUWHwDNv89y/Ygmr1mZZrSJMO9MfkUAom8Rf9MdAwV8e/KixV2e?= =?us-ascii?Q?gh4YHtCrsyP65FoWS/YJfSdO2awxo21V9ItRwN0HvnRUyycbspyP1SQNh1RG?= =?us-ascii?Q?51z/QBlb7o7D9d+cnHMlLwQMkAbvKBF4BHCO8Y/4SfJnNrBMJRNABxynGDVc?= =?us-ascii?Q?BioR5ybjhysfZcPcAtxgXZKT4DpLs+Rohha41Shx9t0Ib9B+0u7WvJpL+AfD?= =?us-ascii?Q?7SLn0lNRi8ZXEGzwZWjgsts6gk7WhVt0+g02LWXFvRhv8lB/1aY8eoXFmfEL?= =?us-ascii?Q?hR6FXesQKV5SqTeFabIXYiGzCu9q38UZZPwZ6+ubgtm5yjgjIEAfmVFGxy9/?= =?us-ascii?Q?I3FFssH5RWyJv2tyF8POHwA2wfU+MfTb5xGTM55ljUD4eQ6ffK03KqOhqyaf?= =?us-ascii?Q?IrEtzA1qv6IKxNwXJvaZfRtfTeeRA2ldupflycyMDquCFhNVkUxv9B8R8Ym4?= =?us-ascii?Q?9hkaUDb0B4ICz0OwAPz2YNUDGxetxIc9RBPDW06Yr8G9bST7vOHsULS1DrZ+?= =?us-ascii?Q?PgcHtqrNkv7zCz2GNClZg+avHbNCftZtwF3n8E89GrR3LjPRckHfNPXrEh4z?= =?us-ascii?Q?STWlM+rFGf1NVbT1As+gTYvhIvr2ERyyKyBm4pk6TzvMk0LJbUEuIYoPp55K?= =?us-ascii?Q?cUW3AKZuvvm9tPJcfFw0hADvdkZQnusEzNFyYJlkusszxC4ybvjJ5jMCHM15?= =?us-ascii?Q?8OpzPvMa8jbTezIbyp2oHjMCvRWNseiD0b95lilTzm1EcaKQxzccRacX1RVL?= =?us-ascii?Q?o1rt4HfkNvsiJmc2rgBhIn6Ebw1Z1w+BvgZn3GiIjbKxfZ9hzMSapDMqDI/P?= =?us-ascii?Q?Ha0vHvOdQfWYDk0ATalFGBui1xS1yGOMu2VQrcRVrnwJgmnvqYeaFcPJ/LRh?= =?us-ascii?Q?5UM0AR5zhZ9JKDrGr7/6DWqdO4yndCGq8jIAd3qK7F1geWnf9zkNzHdn6nh7?= =?us-ascii?Q?aBMLTpONVAIV+90TFmz5d5Cp3xLtBnLMzC91q4hE3ebKzSe2tmF7/TPlIszE?= =?us-ascii?Q?fQeosmh9AanC62l1jL0qcqA+KCL98KHPJRz17R7VsXyMIaoYjTtaYjOIcAGX?= =?us-ascii?Q?2T4OIIFz7/HPIhFkd0OoQrDtQqoqeMD7+N0dwPLtzZjhWp7eptzKHp6+gQjz?= =?us-ascii?Q?/9o5RBafMBoVIVoCggwsWM52lOCpgWndwybYhgLVvBzjxVUpdc54sgl/vGue?= =?us-ascii?Q?cT9KBaNtGu3+98MEaRNqQ7jNiW1+nqvypNZtb/q5d0anTMw5HRqfkrXXoSaT?= =?us-ascii?Q?N0XffZykvTP7TkBIC46tHtxyof8IBQHQ/Sn9rP+nzj7+OzcoLNQm+LIOM/dm?= =?us-ascii?Q?8TRaw8JiByqWP6rrfOIw3XwSzWLIQZhZ4baDRbl45wvrfFc7TyuodaBEzdNp?= =?us-ascii?Q?E4KDl0BXhhE8S1IWV2KpqyNfdld801TMUSbM/Jl56EQPdI28LRTH7UixdPb8?= =?us-ascii?Q?ij5fq7jjWIr25H3InYxiaXVoCrySJnoSmpHSiXZZPZ5fKhpqzVRKF/+Kz1hV?= =?us-ascii?Q?+kDbg8OskTlv4xXsnuvCWM+jysUiZwZU0pn9VkbrTSuGashX+G1tAYEoWcu0?= =?us-ascii?Q?bGFabwUSXHs+gggovDHZ7FTunZQ0W5A=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: e66d36c1-6ec0-4ed0-07fe-08de4dbd37aa X-MS-Exchange-CrossTenant-AuthSource: CO6PR10MB5409.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Jan 2026 07:20:21.2581 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: rB/D8q8mhT6w5QjSBhdJPVl21kOzkFNr1rOeh2U13CM6gQ2sRQVoeqZyLk8A9Te9ahP1yNvTU3fnMzN99nQylotVaV5S5mKRoCyP2hrrnlo= X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV8PR10MB7750 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2026-01-06_03,2026-01-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 bulkscore=0 suspectscore=0 malwarescore=0 adultscore=0 mlxscore=0 phishscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2512120000 definitions=main-2601070058 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTA3MDA2MCBTYWx0ZWRfX4YVGRT0Vnwi2 xreJwQkjuPuytkkaWQo8gUnkYJWtqjk1Oiyd2PAWRyXK5AMzkAE27+moeoJ9hFEsu/ZLVYlAAZB 3oy+Rv/SAap3/M35MznZGWQrtDPvn6AJ8oztoWY9L/83xlaLp56qQqw5kksFLwM0cUeAdLBuK22 Ri2h6q9cZGGFXKW5xi4I0aw0rPK9ZystyjZHIbonA63OTscC/BgoLPJLf1WdUrR7WDwC0v2k41w YLCnf1fYwUNam5AgiRaBVJSifM7pRCKrruwzNJrHbd63mAtDhEG/5QhhORc5n/oN0Au8llUgVXS +7vwhzvGYZ1O9MCFHxJwDnT3qHBkqGT4jfV165Tdxztszu9OyQ2fczqRK94+7ua3kev5rMGqNkf vy4OfGFI6JqmeqQVK25FS6jNLIFNThOdeQVJ/66MKMOlzUbHZjqGZBb/FcnSaQeDYniG79MNaUu dyimrbpKe4K/BlHoL8NcFCe8dcnwcHhjIxrLALbk= X-Proofpoint-GUID: rrttDukFFkrp2ZlFQLWc448SZK2wlb2j X-Proofpoint-ORIG-GUID: rrttDukFFkrp2ZlFQLWc448SZK2wlb2j X-Authority-Analysis: v=2.4 cv=WP5yn3sR c=1 sm=1 tr=0 ts=695e0d35 b=1 cx=c_pps a=zPCbziy225d3KhSqZt3L1A==:117 a=zPCbziy225d3KhSqZt3L1A==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=vUbySO9Y5rIA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=yPCof4ZbAAAA:8 a=zd2uoN0lAAAA:8 a=CZTfYOs-HqEX1FBfxHsA:9 cc=ntf awl=host:12109 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: E7813120004 X-Stat-Signature: 4nahaugs3zfh16oi6upcjtcbw1usxcad X-HE-Tag: 1767771473-945460 X-HE-Meta: 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 qx7qp8m9 NAiF+UxB5euGz3oWIFczLcxetGB5J6JZX/iNw62o84xGPc/sfc4IR/QX8qBcQ8OW9lFCT/ViVj1p8HF/2lOc6G7MfHvoDfeJhfqgGU0XlegX7X+2qBTm+j5zIhMNPq3t9Emf9jRDJxbREWR0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: clear_page_rep() and clear_page_erms() are wrappers around "REP; STOS" variations. Inlining gets rid of an unnecessary CALL/RET (which isn't free when using RETHUNK speculative execution mitigations.) Fixup and rename clear_page_orig() to adapt to the changed calling convention. Also add a comment from Dave Hansen detailing various clearing mechanisms used in clear_page(). Signed-off-by: Ankur Arora Tested-by: Raghavendra K T Reviewed-by: Borislav Petkov (AMD) --- arch/x86/include/asm/page_32.h | 6 +++ arch/x86/include/asm/page_64.h | 67 ++++++++++++++++++++++++++-------- arch/x86/lib/clear_page_64.S | 39 ++++---------------- 3 files changed, 66 insertions(+), 46 deletions(-) diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h index 0c623706cb7e..19fddb002cc9 100644 --- a/arch/x86/include/asm/page_32.h +++ b/arch/x86/include/asm/page_32.h @@ -17,6 +17,12 @@ extern unsigned long __phys_addr(unsigned long); #include +/** + * clear_page() - clear a page using a kernel virtual address. + * @page: address of kernel page + * + * Does absolutely no exception handling. + */ static inline void clear_page(void *page) { memset(page, 0, PAGE_SIZE); diff --git a/arch/x86/include/asm/page_64.h b/arch/x86/include/asm/page_64.h index 2f0e47be79a4..ec3307234a17 100644 --- a/arch/x86/include/asm/page_64.h +++ b/arch/x86/include/asm/page_64.h @@ -48,26 +48,63 @@ static inline unsigned long __phys_addr_symbol(unsigned long x) #define __phys_reloc_hide(x) (x) -void clear_page_orig(void *page); -void clear_page_rep(void *page); -void clear_page_erms(void *page); -KCFI_REFERENCE(clear_page_orig); -KCFI_REFERENCE(clear_page_rep); -KCFI_REFERENCE(clear_page_erms); +void __clear_pages_unrolled(void *page); +KCFI_REFERENCE(__clear_pages_unrolled); -static inline void clear_page(void *page) +/** + * clear_page() - clear a page using a kernel virtual address. + * @addr: address of kernel page + * + * Switch between three implementations of page clearing based on CPU + * capabilities: + * + * - __clear_pages_unrolled(): the oldest, slowest and universally + * supported method. Zeroes via 8-byte MOV instructions unrolled 8x + * to write a 64-byte cacheline in each loop iteration. + * + * - "REP; STOSQ": really old CPUs had crummy REP implementations. + * Vendor CPU setup code sets 'REP_GOOD' on CPUs where REP can be + * trusted. The instruction writes 8-byte per REP iteration but + * CPUs can internally batch these together and do larger writes. + * + * - "REP; STOSB": used on CPUs with "enhanced REP MOVSB/STOSB", + * which enumerate 'ERMS' and provide an implementation which + * unlike "REP; STOSQ" above wasn't overly picky about alignment. + * The instruction writes 1-byte per REP iteration with CPUs + * internally batching these together into larger writes and is + * generally fastest of the three. + * + * Note that when running as a guest, features exposed by the CPU + * might be mediated by the hypervisor. So, the STOSQ variant might + * be in active use on some systems even when the hardware enumerates + * ERMS. + * + * Does absolutely no exception handling. + */ +static inline void clear_page(void *addr) { + u64 len = PAGE_SIZE; /* * Clean up KMSAN metadata for the page being cleared. The assembly call - * below clobbers @page, so we perform unpoisoning before it. + * below clobbers @addr, so perform unpoisoning before it. */ - kmsan_unpoison_memory(page, PAGE_SIZE); - alternative_call_2(clear_page_orig, - clear_page_rep, X86_FEATURE_REP_GOOD, - clear_page_erms, X86_FEATURE_ERMS, - "=D" (page), - "D" (page), - "cc", "memory", "rax", "rcx"); + kmsan_unpoison_memory(addr, len); + + /* + * The inline asm embeds a CALL instruction and usually that is a no-no + * due to the compiler not knowing that and thus being unable to track + * callee-clobbered registers. + * + * In this case that is fine because the registers clobbered by + * __clear_pages_unrolled() are part of the inline asm register + * specification. + */ + asm volatile(ALTERNATIVE_2("call __clear_pages_unrolled", + "shrq $3, %%rcx; rep stosq", X86_FEATURE_REP_GOOD, + "rep stosb", X86_FEATURE_ERMS) + : "+c" (len), "+D" (addr), ASM_CALL_CONSTRAINT + : "a" (0) + : "cc", "memory"); } void copy_page(void *to, void *from); diff --git a/arch/x86/lib/clear_page_64.S b/arch/x86/lib/clear_page_64.S index a508e4a8c66a..f7f356e7218b 100644 --- a/arch/x86/lib/clear_page_64.S +++ b/arch/x86/lib/clear_page_64.S @@ -6,30 +6,15 @@ #include /* - * Most CPUs support enhanced REP MOVSB/STOSB instructions. It is - * recommended to use this when possible and we do use them by default. - * If enhanced REP MOVSB/STOSB is not available, try to use fast string. - * Otherwise, use original. + * Zero page aligned region. + * %rdi - dest + * %rcx - length */ - -/* - * Zero a page. - * %rdi - page - */ -SYM_TYPED_FUNC_START(clear_page_rep) - movl $4096/8,%ecx - xorl %eax,%eax - rep stosq - RET -SYM_FUNC_END(clear_page_rep) -EXPORT_SYMBOL_GPL(clear_page_rep) - -SYM_TYPED_FUNC_START(clear_page_orig) - xorl %eax,%eax - movl $4096/64,%ecx +SYM_TYPED_FUNC_START(__clear_pages_unrolled) + shrq $6, %rcx .p2align 4 .Lloop: - decl %ecx + decq %rcx #define PUT(x) movq %rax,x*8(%rdi) movq %rax,(%rdi) PUT(1) @@ -43,16 +28,8 @@ SYM_TYPED_FUNC_START(clear_page_orig) jnz .Lloop nop RET -SYM_FUNC_END(clear_page_orig) -EXPORT_SYMBOL_GPL(clear_page_orig) - -SYM_TYPED_FUNC_START(clear_page_erms) - movl $4096,%ecx - xorl %eax,%eax - rep stosb - RET -SYM_FUNC_END(clear_page_erms) -EXPORT_SYMBOL_GPL(clear_page_erms) +SYM_FUNC_END(__clear_pages_unrolled) +EXPORT_SYMBOL_GPL(__clear_pages_unrolled) /* * Default clear user-space. -- 2.31.1