Received: by 2002:a05:6a10:f347:0:0:0:0 with SMTP id d7csp12163492pxu; Fri, 1 Jan 2021 10:36:58 -0800 (PST) X-Google-Smtp-Source: ABdhPJyYGjyGaTnUV7p6tY6n+pNTmEACQadwrfXmY0W6Ay3vMj/9Krv9uMZaY8ldPYwqq8GHdXN0 X-Received: by 2002:a17:906:478a:: with SMTP id cw10mr5021691ejc.462.1609526217889; Fri, 01 Jan 2021 10:36:57 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1609526217; cv=none; d=google.com; s=arc-20160816; b=Zncu9xCX6kT5hvk+CQ4oUuo9JYhXDdIGR3etQv7ynUTT3e3Hf+OsUQ5UR8cdnJVjun ETrzMA0V4mOi5sslATEpP6n1L+1ALGBMuE0SXBaCe7/ThX9jj2FTGbhLgqDj24SqrvTu gMgG6YTzXu7zlEO+AspIsizM/jvZEOAgP5EflSs4pZVMgPHJDRgCR+TGySm81ifSzp42 OGr2Y4FPfElfLAvfpnkhpkqdvnN2V00WLld3v3JfU5QdIDmm8vCLYoIx5w+c3GnRW0hp gohSrTUSV37timNx0qdvP+UgCJeQBNdiPWQMQg/PtVn/0x2SQMSVJ08Mi4JqlswrpsOk zzqA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :mime-version:accept-language:in-reply-to:references:message-id:date :thread-index:thread-topic:subject:cc:to:from; bh=wjP8T3mQkdfx4TLz+Z5MWGGC8l7TDb2YQqClEvpdjIM=; b=NMfH8chFKsTMwHwbn/0AIO0/B01rqHzKno681wm9XZKbFBZ7GbCpGFhSACP2jpRKUA 27c3MRFUQAG9ToFnUh3cII07qaH1Trr1sfrDr+5id63JCvA1mk9hNX67AYSoVQ/8oDm6 1J3HjwWyLxXmwcg+1Vy/eItjl+8f9dqmQvHEYx0XJ1K2SnuXWSSjSqX0tIljx497Y98E q/YU3gV0griw4JFTynUiDjHsgqPPK9EYDq135vtyPLdehudTc/3Sb2lFqpCCqOru19cP O/xRHRWVXa0sBNVIXf6WfkTEFejvB9FiaKMDT7qSRtu4OOVArrCkSZZpfRJxp6Bot58M 6WSw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id i12si26218013edk.461.2021.01.01.10.36.17; Fri, 01 Jan 2021 10:36:57 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727147AbhAASfJ (ORCPT + 99 others); Fri, 1 Jan 2021 13:35:09 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:41315 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727142AbhAASfJ (ORCPT ); Fri, 1 Jan 2021 13:35:09 -0500 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-122-YkMGaifVNxGZznooJROwZw-1; Fri, 01 Jan 2021 18:33:29 +0000 X-MC-Unique: YkMGaifVNxGZznooJROwZw-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 1 Jan 2021 18:33:28 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 1 Jan 2021 18:33:28 +0000 From: David Laight To: 'Andy Lutomirski' , Nicholas Piggin CC: Arnd Bergmann , X86 ML , LKML , stable , Will Deacon , Mathieu Desnoyers , Catalin Marinas , Paul Mackerras , linuxppc-dev , linux-arm-kernel Subject: RE: [RFC please help] membarrier: Rewrite sync_core_before_usermode() Thread-Topic: [RFC please help] membarrier: Rewrite sync_core_before_usermode() Thread-Index: AQHW3XrLzyrfomRRwUafqZ2cHH9jwqoTGagQ Date: Fri, 1 Jan 2021 18:33:28 +0000 Message-ID: <30c0fd4917264e75a911527715f5aed3@AcuMS.aculab.com> References: <1609199804.yrsu9vagzk.astroid@bobo.none> In-Reply-To: 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogQW5keSBMdXRvbWlyc2tpDQo+IFNlbnQ6IDI5IERlY2VtYmVyIDIwMjAgMDA6MzYNCi4u Lg0KPiBJIG1lYW4gdGhhdCB0aGUgbWFwcGluZyBmcm9tIHRoZSBuYW1lICJzeW5jX2NvcmUiIHRv IGl0cyBzZW1hbnRpY3MgaXMNCj4geDg2IG9ubHkuICBUaGUgc3RyaW5nICJzeW5jX2NvcmUiIGFw cGVhcnMgaW4gdGhlIGtlcm5lbCBvbmx5IGluDQo+IGFyY2gveDg2LCBtZW1iYXJyaWVyIGNvZGUs IG1lbWJhcnJpZXIgZG9jcywgYW5kIGEgc2luZ2xlIFNHSSBkcml2ZXINCj4gdGhhdCBpcyB4ODYt b25seS4gIFN1cmUsIHRoZSBpZGVhIG9mIHNlcmlhbGl6aW5nIHRoaW5ncyBpcyBmYWlybHkNCj4g Z2VuZXJpYywgYnV0IGV4YWN0bHkgd2hhdCBvcGVyYXRpb25zIHNlcmlhbGl6ZSB3aGF0LCB3aGVu IHRoaW5ncyBuZWVkDQo+IHNlcmlhbGl6YXRpb24sIGV0YyBpcyBxdWl0ZSBhcmNoaXRlY3R1cmUg c3BlY2lmaWMuDQo+IA0KPiBIZWNrLCBvbiA0ODYgeW91IHNlcmlhbGl6ZSB0aGUgaW5zdHJ1Y3Rp b24gc3RyZWFtIHdpdGggSk1QLg0KDQpEaWQgdGhlIDQ4NiBldmVuIGhhdmUgYSBtZW1vcnkgY2Fj aGU/DQpOZXZlciBtaW5kIHNlcGFyYXRlIEkmRCBjYWNoZXMuDQpXaXRob3V0IGJyYW5jaCBwcmVk aWN0aW9uIG9yIGFuIEkkIGEgam1wIGlzIGVub3VnaC4NCk5vIGlkZWEgaG93IHRoZSBkdWFsIDQ4 NiBib3ggd2UgaGFkIGFjdHVhbGx5IGJlaGF2ZWQuDQoNCkZvciBub24tU01QIHRoZSB4ODYgY3B1 cyB0ZW5kIHRvIHN0aWxsIGJlIGNvbXBhdGlibGUgd2l0aA0KdGhlIG9yaWdpbmFsIDgwODYgLSBz byBhcmUgcHJldHR5IG11Y2ggZnVsbHkgY29oZXJlbnQuDQpJU1RSIHRoZSBtZW1vcnkgd3JpdGVz IHdpbGwgaW52YWxpZGF0ZSBJJCBsaW5lcy4NCg0KQnV0IHRoZXJlIHdhcyBzb21lIGhhcmR3YXJl IGNvbXBhdGliaWxpdHkgdGhhdCBtZWFudCBhIGxvYWQNCm9mIFBlbnRpdW0tNzUgc3lzdGVtcyB3 ZXJlICdzY2F2ZW5nZWQnIGZyb20gZGV2ZWxvcG1lbnQgZm9yDQphIGN1c3RvbWVyIC0gd2UgZ290 IGZhc3RlciBQLTI2NiBib3hlcyBhcyByZXBsYWNlbWVudHMuDQoNCk9UT0ggd2UgbmV2ZXIgZGlk IHdvcmsgb3V0IGhvdyB0byBkbyB0aGUgcmVxdWlyZWQgJ2JhcnJpZXInDQp3aGVuIHN3aXRjaGlu ZyBhIFZpYSBDMyB0byBhbmQgZnJvbSAxNi1iaXQgbW9kZS4NClNvbWV0aW1lcyBpdCB3b3JrZWQs IG90aGVyIHRpbWVzIHRoZSBjcHUgd2VudCBBV09MLg0KQmVzdCBndWVzcyB3YXMgdGhhdCBpdCBz b21ldGltZXMgZXhlY3V0ZWQgcHJlLWRlY29kZWQNCmluc3RydWN0aW9ucyBmb3IgdGhlIHdyb25n IG1vZGUgd2hlbiByZXR1cm5pbmcgZnJvbSB0aGUNCmZ1bmN0aW9uIGNhbGwgdGhhdCBmbGlwcGVk IG1vZGVzLg0KDQpUaGVuIHRoZXJlIGlzIHRoZSBQLVBybyBlcmEgSW50ZWwgZG9jIHRoYXQgc2F5 cyB0aGF0IElPUi9JT1cNCmFyZW4ndCBzZXF1ZW5jZWQgd3J0IG1lbW9yeSBhY2Nlc3Nlcy4NCkZv cnR1bmF0ZWx5IGFsbCB4ODYgcHJvY2Vzc29ycyBoYXZlIHNlcXVlbmNlZCB0aGVtLg0KV2hpY2gg aXMgd2hhdCB0aGUgY3VycmVudCBkb2NzIHNheS4NCg0KCURhdmlkDQoNCi0NClJlZ2lzdGVyZWQg QWRkcmVzcyBMYWtlc2lkZSwgQnJhbWxleSBSb2FkLCBNb3VudCBGYXJtLCBNaWx0b24gS2V5bmVz LCBNSzEgMVBULCBVSw0KUmVnaXN0cmF0aW9uIE5vOiAxMzk3Mzg2IChXYWxlcykNCg==