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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAF80C433EF for ; Tue, 8 Feb 2022 23:36:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237371AbiBHXgc (ORCPT ); Tue, 8 Feb 2022 18:36:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231418AbiBHXga (ORCPT ); Tue, 8 Feb 2022 18:36:30 -0500 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7A9A1C06173B for ; Tue, 8 Feb 2022 15:36:29 -0800 (PST) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-314-yKUP0R1ROeSG8Jqez4S79Q-1; Tue, 08 Feb 2022 23:36:26 +0000 X-MC-Unique: yKUP0R1ROeSG8Jqez4S79Q-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.28; Tue, 8 Feb 2022 23:36:25 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.028; Tue, 8 Feb 2022 23:36:25 +0000 From: David Laight To: 'Borislav Petkov' , Hugh Dickins CC: Peter Zijlstra , "linux-kernel@vger.kernel.org" , "x86@kernel.org" Subject: RE: x86: should clear_user() have alternatives? Thread-Topic: x86: should clear_user() have alternatives? Thread-Index: AQHYHOq85MEK9qlbxkOnyE8hF1HtfqyKS9+Q Date: Tue, 8 Feb 2022 23:36:25 +0000 Message-ID: References: <2f5ca5e4-e250-a41c-11fb-a7f4ebc7e1c9@google.com> 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 RnJvbTogQm9yaXNsYXYgUGV0a292DQo+IFNlbnQ6IDA4IEZlYnJ1YXJ5IDIwMjIgMTI6NTMNCj4g DQo+IE9uIE1vbiwgRmViIDA3LCAyMDIyIGF0IDA5OjQ1OjM2UE0gLTA4MDAsIEh1Z2ggRGlja2lu cyB3cm90ZToNCj4gPiBJIHJlYWxpemUgdGhhdCBkZCdpbmcgZnJvbSAvZGV2L3plcm8gdG8gL2Rl di9udWxsLCBhbmQgc3BhcnNlIGZpbGVzIG9uDQo+ID4gdG1wZnMsIGFyZSBub3QgcHJpbWUgY2Fu ZGlkYXRlcyBmb3Igb3B0aW1pemF0aW9uOyBhbmQgSSd2ZSBubyBpZGVhIGhvdw0KPiA+IG11Y2gg Y2xlYXJfdXNlcigpIG5vcm1hbGx5IGdldHMgdXNlZCBmb3IgbG9uZyBjbGVhcnMuDQo+IA0KPiBS aWdodCwgd2UgdXN1YWxseSBkb24ndCB0YWtlIHN1Y2ggIm9wdGltaXphdGlvbnMiIGJlY2F1c2Ug dGhlIGZvbGtzIHdobw0KPiBzZW5kIHRoZW0gYWx3YXlzIGNvbWUgdXAgd2l0aCBlaXRoZXIgbWlj cm9iZW5jaG1hcmtzIG9yIG9ubHkgdGVzdCBvbiBhDQo+IHNpbmdsZSBtYWNoaW5lLg0KDQpJIHRo aW5rIGl0IGlzIHJlYXNvbmFibGUgdG8gdXNlIG1pY3JvYmVuY2htYXJrcyB0byBzZWUgaG93IGZh c3QNCmEgcGFydGljdWxhciBsb29wIHJ1bnMgb24gYSBzcGVjaWZpYyBjcHUgLSBzaW5jZSB5b3Ug Y2FuIHdvcmsgb3V0DQp0aGUgbnVtYmVyIG9mIGNsb2NrcyBwZXIgaXRlcmF0aW9uIGFuZCBkaXJl Y3RseSBjb21wYXJlIGRpZmZlcmVudA0KdmVyc2lvbnMuDQoNClRoZSBwcm9ibGVtIHdpdGggbWlj cm9iZW5jaG1hcmtzIGlzIHdoZW4gdGhleSBnZXQgdXNlZCBvbiB1bnJvbGxlZCBsb29wcy4NClJ1 biBzb21ldGhpbmcgMTAwMDAgdGltZXMgd2l0aCBob3QtY2FjaGUgZGF0YSBhbmQgdW5yb2xsZWQg bG9vcHMNCmFsbW9zdCBhbHdheXMgc2VlbSBiZXN0Lg0KQ29sZCBjYWNoZSBvciB0aGUgZWZmZWN0 cyBvZiBkaXNwbGFjaW5nIG90aGVyIGNvZGUgZnJvbSB0aGUgSS1jYWNoZQ0KY2FuIG1ha2UgbG9v cCB1bnJvbGxpbmcgYSBiaWcgbG9zcy4NCkVzcGVjaWFsbHkgb24gY3VycmVudCBjcHUgdGhhdCBl eGVjdXRlIG11bHRpcGxlIGluc3RydWN0aW9ucy9jbG9jaw0KYW5kIG91dC1vZi1vcmRlciBleGVj dXRpb24uDQoNCkxvb3BzIG9ubHkgbmVlZCB1bnJvbGxpbmcganVzdCBlbm91Z2ggdG8gaGl0IHNv bWUgYXJjaGl0ZWN0dXJhbCBsaW1pdC4NCkZvciBtZW1zZXQoKSAodXNpbmcgbm9ybWFsIGluc3Ry dWN0aW9ucykgdGhhdCBpcyAxIHdyaXRlIHBlciBjbG9jay4NCg0KQSBjbGFzc2ljIGV4YW1wbGUg aGFzIHRvIGJlIHRoZSBzcGFyYyBkaXZpZGUgcmVtYWluZGVyIGZ1bmN0aW9uDQppbiB0aGUgb3Jp Z2luYWwgQ1k3QzYwMCBib29rICh3aGljaCBJIGhhcHBlbiB0byBzdGlsbCBoYXZlKS4NCkknbSBu b3Qgc3VyZSBob3cgbWFueSBpbnN0cnVjdGlvbnMgaXQgaXMgLSBidXQgaXQgaXMgcHJpbnRlZA0K b24gNCBwYWdlcy4gSXQganVzdCBoYXMgdG8gYmxvdyBhbnl0aGluZyBlbHNlIG91dCBvZiB0aGUN CnNtYWxsIEktY2FjaGUgdGhvc2UgY3B1IGhhZC4NCkl0IG1pZ2h0IGJlIGZhc3RlciAtIGJ1dCBv bmx5IGlmIHlvdSBhcmUgZG9pbmcgYSBsb3Qgb2YgZGl2aWRlcy4NCiANCglEYXZpZA0KDQotDQpS ZWdpc3RlcmVkIEFkZHJlc3MgTGFrZXNpZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWls dG9uIEtleW5lcywgTUsxIDFQVCwgVUsNClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMp DQo=