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 A2413D5E362 for ; Sat, 9 Nov 2024 09:55:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:In-Reply-To:References:Message-ID:Date:Subject:CC: To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tRYsZ6ayQwcEYxFCPqmKlN9mSzxWMkZ1FBBiuyaMlc0=; b=m12RbrxNESRQY3Hxb/Q4tMDChi xSpQ0GawJzBzUvEyLTJ6lqh5I/CEDzpwTM645koq0adUUtC4yCBpFhjWX2UfpMKdM/f6Oe2HeaWrd 9XigJ8iPvH3ev2QBUS3Gd6eFHm0oKyPBG0eX6LNnspOtw54cRdx5D88z6UQUy95+7H5/rcfYfB7GN XBONIwRoFlg60we8L9MPpxnmVM+FWgy4DsB5RLLO7V6PtfGEwDUhSBgNZnI+6qvqWApHiSvVoGqZB Tfc/CVztmcOY2I7LgGYBcMvVqPZKv0ZqqADbNmxZ758BEjcs3hXZfgUoscocfiWBB9vkEdMqir1ou yHR0qLQQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t9iBz-0000000D1lq-3VRf; Sat, 09 Nov 2024 09:55:43 +0000 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.85.151]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t9i5d-0000000D14F-27Kk for linux-arm-kernel@lists.infradead.org; Sat, 09 Nov 2024 09:49:11 +0000 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-94-S7JoMMDMMHS9cQ8RB_P-nQ-1; Sat, 09 Nov 2024 09:49:05 +0000 X-MC-Unique: S7JoMMDMMHS9cQ8RB_P-nQ-1 X-Mimecast-MFC-AGG-ID: S7JoMMDMMHS9cQ8RB_P-nQ Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Sat, 9 Nov 2024 09:49:04 +0000 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Sat, 9 Nov 2024 09:49:04 +0000 From: David Laight To: 'Haris Okanovic' , "ankur.a.arora@oracle.com" , "catalin.marinas@arm.com" CC: "linux-pm@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "will@kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "pbonzini@redhat.com" , "wanpengli@tencent.com" , "vkuznets@redhat.com" , "rafael@kernel.org" , "daniel.lezcano@linaro.org" , "peterz@infradead.org" , "arnd@arndb.de" , "lenb@kernel.org" , "mark.rutland@arm.com" , "mtosatti@redhat.com" , "sudeep.holla@arm.com" , "cl@gentwo.org" , "misono.tomohiro@fujitsu.com" , "maobibo@loongson.cn" , "joao.m.martins@oracle.com" , "boris.ostrovsky@oracle.com" , "konrad.wilk@oracle.com" Subject: RE: [PATCH 2/5] arm64: add __READ_ONCE_EX() Thread-Topic: [PATCH 2/5] arm64: add __READ_ONCE_EX() Thread-Index: AQHbL7EN8akEXkbcIke1iZkICXXDerKutxnw Date: Sat, 9 Nov 2024 09:49:03 +0000 Message-ID: References: <20240925232425.2763385-1-ankur.a.arora@oracle.com> <20241105183041.1531976-1-harisokn@amazon.com> <20241105183041.1531976-3-harisokn@amazon.com> In-Reply-To: <20241105183041.1531976-3-harisokn@amazon.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: a7PP8zGbzz70Ult_MhBmiSKqkDHbc8W_9LoErMJXBSc_1731145744 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241109_014909_842478_1653FCF4 X-CRM114-Status: UNSURE ( 5.33 ) 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 From: Haris Okanovic > Sent: 05 November 2024 18:31 >=20 > Perform an exclusive load, which atomically loads a word and arms the > exclusive monitor to enable wfet()/wfe() accelerated polling. >=20 ... > +=09atomic ? (typeof(*__x))__u.__val : (*(volatile typeof(__x))__x);\ That doesn't do what you want it to do. (It is wrong in READ_ONCE() as well.) ?: is treated like an arithmetic operator and the result will get promoted to 'int'. Moving the first cast outside the ?: probably works: =09(typeof(*__x))(atomic ? __u.__val : (*(volatile typeof(__x))__x)); David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)