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 2B34FC433F5 for ; Tue, 3 May 2022 08:14:56 +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-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2OC92QaOL0waCSQByijB4GMGT38VtbtnOoNOD4jIQcY=; b=zQ4jNgBrl6qb/Z 2vmMkiw5yx5CwUQyz6i1eRP53T67EcFxVuerxWuNhUgswRfLAvsGSmOi3LgEOrFuxKFX0cEvi74ec kOIyjjtbC0AK/ZRs+Tnyv8lTmaZQ/SB7Ishx7tDWHB8RCerESIrLuDKykd4pCyAdV+/m/+wnz5Olz tluMwvYjZrQt15Ay/Kf4wYysOrDo1z8hdzhpn5naX1oHiQM4xTgfnx5tA8Qv9dVOMT/q3EU91HcbD KNIheH3ZFj1xA7/8XItrN5kVbTB2eqC02c7UoS6vWGZJIVvy2n2FlTOBcOC0Sp4UsLQbYkmhK3Y2B x7Rzg/Wvpp5Fv2CTj7iQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlnfF-004YkI-VN; Tue, 03 May 2022 08:13:46 +0000 Received: from mail-am6eur05on20608.outbound.protection.outlook.com ([2a01:111:f400:7e1b::608] helo=EUR05-AM6-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nlnfC-004Yj5-Fw for linux-arm-kernel@lists.infradead.org; Tue, 03 May 2022 08:13:44 +0000 ARC-Seal: i=2; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=pass; b=QYjfiODHFNXILZ8p9ShuBK3dt9D+IS5bvaIfJQfezFJTCacAFLNVRhXsAejEkloVo7jQyAjM7o4A6Hr8GpHDy9w0LHxeV8Sw0U15QcWNkeOZh1+zdoq94igI+hbkrQSwZ+d+I+KwRll36jFykP3iFGPRbWlhhdKXtyY65p2Mav6UEIewCcU/ZGSISSiITmV4CIIngysTP72SptX3nzOy6yulaTsgYBh35nI8DhuwubRioWckImluLmUBaR3nR4cRvi0TZU/VN/GQ9Q12yFdvcF2drJrNsc6JggDIWuwenr+4cyJzCGm9RYq9QQAayvn5Y1tTa2FjcjiejslNhtv/xw== ARC-Message-Signature: i=2; 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=12P3TpUwPZFrXtxik6iYyEVWFTiih5G83nj9vFeYXTs=; b=k/OaB1VTX00u1eYbhDZ39gtAhYE/1DigyjDloIDI3MmGJBuv3UQWt3sdq9tZvNWmS9hyeTblTxvnZmgBVvHAto4485e782+mEBmVO9YGqsL8ZH0sikW/Sipty5Y0EprsOEbutU5p47hUOrqunv/BKhLRouTkvo0ShT5CZgLThnGVd1TftdFiztnyCigfUiFPW80z4Y1NFEql6XDE4EWuDhFv11kBuoAIslWAFzT/eR9P9tADIYUvavvg3P2hy1Iy5cYXb1I2yFKKt0UjQuABnWNL3NkZgjiM/uyZcx8F8Np7JVzp2vcOFPfT/WQndcYKE3exDOMID+FEUS2UMHOvjA== ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 63.35.35.123) smtp.rcpttodomain=lists.infradead.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=armh.onmicrosoft.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=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=12P3TpUwPZFrXtxik6iYyEVWFTiih5G83nj9vFeYXTs=; b=oxLcyTNlUUZXOVmI3aGeXsdGDrD2enp+GkVHVZqqytfhSaZ9Q+sXyXVH3YzVFdSqLgf1XySxflfHgO5R7QtuWI84RDSL4xvWRMWv+eJSLuE/E20P3NCNxHhicfgxwLymLh5fgHU72GS6DL8smsvixMs7PmNNxibQ6poF2LBIvEY= Received: from AS9P250CA0019.EURP250.PROD.OUTLOOK.COM (2603:10a6:20b:532::23) by PAXPR08MB6970.eurprd08.prod.outlook.com (2603:10a6:102:1d9::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5206.14; Tue, 3 May 2022 08:13:34 +0000 Received: from AM5EUR03FT053.eop-EUR03.prod.protection.outlook.com (2603:10a6:20b:532:cafe::b2) by AS9P250CA0019.outlook.office365.com (2603:10a6:20b:532::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5206.24 via Frontend Transport; Tue, 3 May 2022 08:13:34 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 63.35.35.123) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=armh.onmicrosoft.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 63.35.35.123 as permitted sender) receiver=protection.outlook.com; client-ip=63.35.35.123; helo=64aa7808-outbound-1.mta.getcheckrecipient.com; Received: from 64aa7808-outbound-1.mta.getcheckrecipient.com (63.35.35.123) by AM5EUR03FT053.mail.protection.outlook.com (10.152.16.210) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5206.12 via Frontend Transport; Tue, 3 May 2022 08:13:34 +0000 Received: ("Tessian outbound facaf1373bbd:v118"); Tue, 03 May 2022 08:13:34 +0000 X-CheckRecipientChecked: true X-CR-MTA-CID: b02e5ef33f797400 X-CR-MTA-TID: 64aa7808 Received: from 8bf7a89e5314.2 by 64aa7808-outbound-1.mta.getcheckrecipient.com id CEA04689-D191-4A71-9508-1BB37F29BDD8.1; Tue, 03 May 2022 08:13:27 +0000 Received: from EUR03-AM5-obe.outbound.protection.outlook.com by 64aa7808-outbound-1.mta.getcheckrecipient.com with ESMTPS id 8bf7a89e5314.2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384); Tue, 03 May 2022 08:13:27 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=j/4ms4zDht8g0p6y61Ye9jnEPZ/mJdogLUbGEbiHY+3rWDvX8y3U2Z634H9vY2JxnFZc6cLWmp8efM39icwfZm/QE/+21vRmGBMKGOBHxQxmSGHl4BDKfavdsPRzjLynTHDGQI7tZCQx/CGw5qyUtnml8DcfNx3vlzzqYIn1afG4Y/G/vy4N2jX6ftBVx54jKm1AbnX1hqxubaIde7z+QEL3Z4CkqsK2z2gGOdYu2JVsUSh/rtzfalgFcDGzEMK9GkQ4YINdSozR0YtvPA+AAnbYjtLsabmVnb7R2iVHHEw1a+d1nk7eiMEoHMbZlp6XD/a9QDi6s0Y3Zd4a/4gB8g== 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=12P3TpUwPZFrXtxik6iYyEVWFTiih5G83nj9vFeYXTs=; b=mamvmsyF7qnaOQpWE2btRbHI00yfkn9J68aFnGBfIz224F9s3D2sVoDkOAk9ZMEwkjzUQ0p0WWlQ1pw6p8WrqUSO6N9e7VW2J7qOW+zUainz5TgOv3m1/LVMtWqU2OZkKClbpvxbc9RQJY9DzU+2hu9Wq5Ni8nz5crn9tPn1mac5RUkpXEYZdwRubm54zhHKW8IBnbayYuOGL3KgBRNne7BO0kYo+lTgBxFmX4HwWP1Zh+5AcdwXmaOQXgZ2O18mVlj7LqaMTblnkx4D4S+V2oeF6nJaDDhf0vwSV6WjEiIH6xUoCh8qGdXoJQi/iXjDGWY1uXG9KamQ3JcBMt3YcA== 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=armh.onmicrosoft.com; s=selector2-armh-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=12P3TpUwPZFrXtxik6iYyEVWFTiih5G83nj9vFeYXTs=; b=oxLcyTNlUUZXOVmI3aGeXsdGDrD2enp+GkVHVZqqytfhSaZ9Q+sXyXVH3YzVFdSqLgf1XySxflfHgO5R7QtuWI84RDSL4xvWRMWv+eJSLuE/E20P3NCNxHhicfgxwLymLh5fgHU72GS6DL8smsvixMs7PmNNxibQ6poF2LBIvEY= Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; Received: from DB9PR08MB7179.eurprd08.prod.outlook.com (2603:10a6:10:2cc::19) by DB7PR08MB3404.eurprd08.prod.outlook.com (2603:10a6:10:4c::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5186.19; Tue, 3 May 2022 08:13:25 +0000 Received: from DB9PR08MB7179.eurprd08.prod.outlook.com ([fe80::9ccc:fe7c:19e5:bfa6]) by DB9PR08MB7179.eurprd08.prod.outlook.com ([fe80::9ccc:fe7c:19e5:bfa6%4]) with mapi id 15.20.5206.024; Tue, 3 May 2022 08:13:25 +0000 Date: Tue, 3 May 2022 09:13:11 +0100 From: Szabolcs Nagy To: Catalin Marinas Cc: Mark Brown , Will Deacon , Marc Zyngier , Shuah Khan , Shuah Khan , Alan Hayward , Luis Machado , Salil Akerkar , Basant Kumar Dwivedi , James Morse , Alexandru Elisei , Suzuki K Poulose , Luca Salabrino , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH v14 04/39] arm64/sme: Provide ABI documentation for SME Message-ID: References: <20220419112247.711548-1-broonie@kernel.org> <20220419112247.711548-5-broonie@kernel.org> Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: AM0PR04CA0048.eurprd04.prod.outlook.com (2603:10a6:208:1::25) To DB9PR08MB7179.eurprd08.prod.outlook.com (2603:10a6:10:2cc::19) MIME-Version: 1.0 X-MS-Office365-Filtering-Correlation-Id: 3ffada8e-a3a2-4cb8-8d2c-08da2cdcd188 X-MS-TrafficTypeDiagnostic: DB7PR08MB3404:EE_|AM5EUR03FT053:EE_|PAXPR08MB6970:EE_ X-Microsoft-Antispam-PRVS: x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0; X-Microsoft-Antispam-Message-Info-Original: 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 X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DB9PR08MB7179.eurprd08.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230001)(4636009)(366004)(6486002)(86362001)(6636002)(6512007)(26005)(66476007)(66946007)(4326008)(66556008)(6506007)(6862004)(8676002)(508600001)(316002)(6666004)(38100700002)(54906003)(36756003)(37006003)(2906002)(8936002)(5660300002)(2616005)(186003)(44832011)(67856001); DIR:OUT; SFP:1101; X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB7PR08MB3404 Original-Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: AM5EUR03FT053.eop-EUR03.prod.protection.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: 0a863e43-6aed-4b8f-0fda-08da2cdccc16 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:63.35.35.123; CTRY:IE; LANG:en; SCL:1; SRV:; IPV:CAL; SFV:NSPM; H:64aa7808-outbound-1.mta.getcheckrecipient.com; PTR:ec2-63-35-35-123.eu-west-1.compute.amazonaws.com; CAT:NONE; SFS:(13230001)(4636009)(46966006)(40470700004)(36840700001)(4326008)(70586007)(8676002)(107886003)(40460700003)(6862004)(47076005)(70206006)(336012)(2616005)(6636002)(36860700001)(186003)(316002)(37006003)(54906003)(81166007)(2906002)(6512007)(86362001)(26005)(6506007)(6666004)(36756003)(82310400005)(44832011)(356005)(5660300002)(8936002)(6486002)(508600001)(67856001); DIR:OUT; SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 May 2022 08:13:34.5536 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 3ffada8e-a3a2-4cb8-8d2c-08da2cdcd188 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d; Ip=[63.35.35.123]; Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: AM5EUR03FT053.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAXPR08MB6970 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220503_011342_563263_C59BC49D X-CRM114-Status: GOOD ( 16.77 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The 04/28/2022 10:19, Catalin Marinas wrote: > On Tue, Apr 19, 2022 at 12:22:12PM +0100, Mark Brown wrote: > > +* There are a number of optional SME features, presence of these is reported > > + through AT_HWCAP2 through: > > + > > + HWCAP2_SME_I16I64 > > + HWCAP2_SME_F64F64 > > + HWCAP2_SME_I8I32 > > + HWCAP2_SME_F16F32 > > + HWCAP2_SME_B16F32 > > + HWCAP2_SME_F32F32 > > + HWCAP2_SME_FA64 > > Marc pointed out that in combination with FEAT_WFxT, we used all the > HWCAP2 bits (32). While we are ok for now, we'll soon need to look into > what to do when the next features turn up. Some options: > > 1. Only provide HWCAP2_SME and let the ID_AA64SMFR0_EL1 features be > probed via MRS emulation. It doesn't solve the problem but it buys us > a bit of time. > > 2. Don't bother with any new HWCAPs, just rely on MRS emulation (we have > HWCAP_CPUID advertising this). > > 3. Start using the upper 32-bit of HWCAP and HWCAP2 (we initially didn't > go into these as there was a slight chance of merging ILP32). Does > the libc rely on the upper bits for anything? Or does it just assume > a 32-bit HWCAPs layout? top 2 bits of a 64bit AT_HWCAP should be reserved for libc. (glibc uses them internally) otherwise glibc can work with 64bit hwcaps. > > 4. Introduce HWCAP3. > > Szabolcs, any thoughts? i'd go with AT_HWCAP3 and keep using the bottom 32bit for now. (this requires some new code in glibc, but not excessive) thanks. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel