From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: base64 Return-path: In-Reply-To: Content-Language: en-US List-ID: Content-Type: text/plain; charset="us-ascii" To: 'Linus Torvalds' , Arnd Bergmann Cc: Mark Rutland , Rich Felker , "linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linux-sh list , Peter Zijlstra , "open list:BROADCOM NVRAM DRIVER" , Max Filippov , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , Brian Cain , "open list:QUALCOMM HEXAGON..." , Helge Deller , the arch/x86 maintainers , Russell RnJvbTogTGludXMgVG9ydmFsZHMNCj4gU2VudDogMTQgRmVicnVhcnkgMjAyMiAyMDoyNA0KPiA+ DQo+ID4geDg2LTY0IGhhcyBhbHdheXMoKikgdXNlZCBUQVNLX1NJWkVfTUFYIGZvciBhY2Nlc3Nf b2soKSwgYW5kIHRoZQ0KPiA+IGdldF91c2VyKCkgYXNzZW1ibGVyIGltcGxlbWVudGF0aW9uIGRv ZXMgdGhlIHNhbWUuDQo+IA0KPiBTaWRlIG5vdGU6IHdlIGNvdWxkIGp1c3QgY2hlY2sgdGhlIHNp Z24gYml0IGluc3RlYWQsIGFuZCBhdm9pZCBiaWcNCj4gY29uc3RhbnRzIHRoYXQgd2F5Lg0KDQpU aGUgY2hlYXAgdGVzdCBmb3IgbW9zdCA2NGJpdCBpcyAoYWRkciB8IHNpemUpID4+IDYyICE9IDAu DQoNCkkgZGlkIHNvbWUgdGVzdHMgbGFzdCB3ZWVrIGFuZCB0aGUgY29tcGlsZXJzIGNvcnJlY3Rs eSBvcHRpbWlzZQ0Kb3V0IGNvbnN0YW50IHNpemUuDQoNCkRvZXNuJ3Qgc3BhcmM2NCBzdGlsbCBu ZWVkIGEgd3JhcCB0ZXN0Pw0KT3IgaXMgdGhhdCBhc3N1bWVkIGJlY2F1c2UgdGhlcmUgaXMgYWx3 YXlzIGFuIHVubWFwcGVkIHBhZ2UNCmFuZCB0cmFuc2ZlciBhcmUgJ2FkZXF1YXRlbHknIGRvbmUg b24gaW5jcmVhc2luZyBhZGRyZXNzZXM/DQoNCglEYXZpZA0KDQotDQpSZWdpc3RlcmVkIEFkZHJl c3MgTGFrZXNpZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWlsdG9uIEtleW5lcywgTUsx IDFQVCwgVUsNClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMpDQo= 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 E29BDC433FE for ; Mon, 14 Feb 2022 22:13:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231757AbiBNWNt (ORCPT ); Mon, 14 Feb 2022 17:13:49 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231738AbiBNWNs (ORCPT ); Mon, 14 Feb 2022 17:13:48 -0500 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 99FD013D92C for ; Mon, 14 Feb 2022 14:13:39 -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-3-0IuFZHXpM1-VcUsNfepTpQ-1; Mon, 14 Feb 2022 22:13:36 +0000 X-MC-Unique: 0IuFZHXpM1-VcUsNfepTpQ-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; Mon, 14 Feb 2022 22:13:34 +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; Mon, 14 Feb 2022 22:13:34 +0000 From: David Laight To: 'Linus Torvalds' , Arnd Bergmann CC: Mark Rutland , Rich Felker , "linux-ia64@vger.kernel.org" , Linux-sh list , Peter Zijlstra , "open list:BROADCOM NVRAM DRIVER" , Max Filippov , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , "Brian Cain" , "open list:QUALCOMM HEXAGON..." , Helge Deller , "the arch/x86 maintainers" , Russell King - ARM Linux , "linux-csky@vger.kernel.org" , Christoph Hellwig , "Christoph Hellwig" , Ingo Molnar , "Geert Uytterhoeven" , "open list:SYNOPSYS ARC ARCHITECTURE" , "open list:TENSILICA XTENSA PORT (xtensa)" , Arnd Bergmann , Heiko Carstens , linux-um , Richard Weinberger , linux-m68k , Openrisc , Greentime Hu , Stafford Horne , "Linux ARM" , Michal Simek , Thomas Bogendoerfer , Nick Hu , Parisc List , Linux-MM , Linux API , "Linux Kernel Mailing List" , Dinh Nguyen , "Eric W . Biederman" , alpha , Andrew Morton , linuxppc-dev , David Miller , Al Viro Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Topic: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Index: AQHYIeHe9n+22PBgtUWxf89GrdwkK6yTmyQw Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> 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-api@vger.kernel.org RnJvbTogTGludXMgVG9ydmFsZHMNCj4gU2VudDogMTQgRmVicnVhcnkgMjAyMiAyMDoyNA0KPiA+ DQo+ID4geDg2LTY0IGhhcyBhbHdheXMoKikgdXNlZCBUQVNLX1NJWkVfTUFYIGZvciBhY2Nlc3Nf b2soKSwgYW5kIHRoZQ0KPiA+IGdldF91c2VyKCkgYXNzZW1ibGVyIGltcGxlbWVudGF0aW9uIGRv ZXMgdGhlIHNhbWUuDQo+IA0KPiBTaWRlIG5vdGU6IHdlIGNvdWxkIGp1c3QgY2hlY2sgdGhlIHNp Z24gYml0IGluc3RlYWQsIGFuZCBhdm9pZCBiaWcNCj4gY29uc3RhbnRzIHRoYXQgd2F5Lg0KDQpU aGUgY2hlYXAgdGVzdCBmb3IgbW9zdCA2NGJpdCBpcyAoYWRkciB8IHNpemUpID4+IDYyICE9IDAu DQoNCkkgZGlkIHNvbWUgdGVzdHMgbGFzdCB3ZWVrIGFuZCB0aGUgY29tcGlsZXJzIGNvcnJlY3Rs eSBvcHRpbWlzZQ0Kb3V0IGNvbnN0YW50IHNpemUuDQoNCkRvZXNuJ3Qgc3BhcmM2NCBzdGlsbCBu ZWVkIGEgd3JhcCB0ZXN0Pw0KT3IgaXMgdGhhdCBhc3N1bWVkIGJlY2F1c2UgdGhlcmUgaXMgYWx3 YXlzIGFuIHVubWFwcGVkIHBhZ2UNCmFuZCB0cmFuc2ZlciBhcmUgJ2FkZXF1YXRlbHknIGRvbmUg b24gaW5jcmVhc2luZyBhZGRyZXNzZXM/DQoNCglEYXZpZA0KDQotDQpSZWdpc3RlcmVkIEFkZHJl c3MgTGFrZXNpZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWlsdG9uIEtleW5lcywgTUsx IDFQVCwgVUsNClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMpDQo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Mon, 14 Feb 2022 22:13:34 +0000 Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Message-Id: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> List-Id: References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Linus Torvalds' , Arnd Bergmann Cc: Mark Rutland , Rich Felker , "linux-ia64@vger.kernel.org" , Linux-sh list , Peter Zijlstra , "open list:BROADCOM NVRAM DRIVER" , Max Filippov , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , Brian Cain , "open list:QUALCOMM HEXAGON..." , Helge Deller , the arch/x86 maintainers , Russell King - ARM Linux , "linux-csky@vger.kernel.org" , Christoph Hellwig , Christoph Hellwig , Ingo Molnar , Geert Uytterhoeven , "open list:SYNOPSYS ARC ARCHITECTURE" , "open list:TENSILICA XTENSA PORT (xtensa)" , Arnd Bergmann , Heiko Carstens , linux-um , Richard Weinberger , linux-m68k , Openrisc , Greentime Hu , Stafford Horne , Linux ARM , Michal Simek , Thomas Bogendoerfer , Nick Hu , Parisc List , Linux-MM , Linux API , Linux Kernel Mailing List , Dinh Nguyen , "Eric W . 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Biederman" , alpha , Andrew Morton , linuxppc-dev , David Miller , Al Viro Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Topic: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Index: AQHYIeHe9n+22PBgtUWxf89GrdwkK6yTmyQw Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220214_141342_864798_5143958F X-CRM114-Status: GOOD ( 10.20 ) X-BeenThere: linux-riscv@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-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Linus Torvalds > Sent: 14 February 2022 20:24 > > > > x86-64 has always(*) used TASK_SIZE_MAX for access_ok(), and the > > get_user() assembler implementation does the same. > > Side note: we could just check the sign bit instead, and avoid big > constants that way. The cheap test for most 64bit is (addr | size) >> 62 != 0. I did some tests last week and the compilers correctly optimise out constant size. Doesn't sparc64 still need a wrap test? Or is that assumed because there is always an unmapped page and transfer are 'adequately' done on increasing addresses? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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 71BB2C433F5 for ; Mon, 14 Feb 2022 22:13:49 +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: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=i4ZWDGU38nEn6Lw92KZpZxXqQ72X9NSk6aCHkvThc+w=; b=1r1FHBP7sXt8l7 AfEDBVDQ+NfLs1tq/NjlRWyOXehmk4MWAM2nqXUMHRcAfMmUE98qXXU7L1kTCT/QXdnv+CEuVMl5A hErvblGXZbkQ/1l00hhoI6DKWy4yfChmF+rCN8V01bq5atVHgaejkQFHhGRw24ysgL1IZhTZyCHAc awnI8F+yKL1BJ6/WLK4Ab8QXMC0Qh3BvCtyadk7skvtN7Ipl//QW2zdLtaf/XC+c0cPK4FBdD3XZ3 omTt+Ui8wftJIBpVR0ibY/DE5hHpNX9mXtt5mOWiJ5KYIyCKJE7dREAfED/ReSpB51A5eEFHvnUxX gV9AH4r65o+DlThX0CSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJjbP-00HBqT-41; Mon, 14 Feb 2022 22:13:47 +0000 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJjbK-00HBmS-Fr for linux-snps-arc@lists.infradead.org; Mon, 14 Feb 2022 22:13:45 +0000 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-3-0IuFZHXpM1-VcUsNfepTpQ-1; Mon, 14 Feb 2022 22:13:36 +0000 X-MC-Unique: 0IuFZHXpM1-VcUsNfepTpQ-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; Mon, 14 Feb 2022 22:13:34 +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; Mon, 14 Feb 2022 22:13:34 +0000 From: David Laight To: 'Linus Torvalds' , Arnd Bergmann CC: Mark Rutland , Rich Felker , "linux-ia64@vger.kernel.org" , Linux-sh list , Peter Zijlstra , "open list:BROADCOM NVRAM DRIVER" , Max Filippov , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , "Brian Cain" , "open list:QUALCOMM HEXAGON..." , Helge Deller , "the arch/x86 maintainers" , Russell King - ARM Linux , "linux-csky@vger.kernel.org" , Christoph Hellwig , "Christoph Hellwig" , Ingo Molnar , "Geert Uytterhoeven" , "open list:SYNOPSYS ARC ARCHITECTURE" , "open list:TENSILICA XTENSA PORT (xtensa)" , Arnd Bergmann , Heiko Carstens , linux-um , Richard Weinberger , linux-m68k , Openrisc , Greentime Hu , Stafford Horne , "Linux ARM" , Michal Simek , Thomas Bogendoerfer , Nick Hu , Parisc List , Linux-MM , Linux API , "Linux Kernel Mailing List" , Dinh Nguyen , "Eric W . Biederman" , alpha , Andrew Morton , linuxppc-dev , David Miller , Al Viro Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Topic: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Index: AQHYIeHe9n+22PBgtUWxf89GrdwkK6yTmyQw Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220214_141342_855295_AFBE27AA X-CRM114-Status: GOOD ( 10.20 ) X-BeenThere: linux-snps-arc@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux on Synopsys ARC Processors List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+linux-snps-arc=archiver.kernel.org@lists.infradead.org From: Linus Torvalds > Sent: 14 February 2022 20:24 > > > > x86-64 has always(*) used TASK_SIZE_MAX for access_ok(), and the > > get_user() assembler implementation does the same. > > Side note: we could just check the sign bit instead, and avoid big > constants that way. The cheap test for most 64bit is (addr | size) >> 62 != 0. I did some tests last week and the compilers correctly optimise out constant size. Doesn't sparc64 still need a wrap test? Or is that assumed because there is always an unmapped page and transfer are 'adequately' done on increasing addresses? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: David Laight Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> In-Reply-To: MIME-Version: 1.0 Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 To: 'Linus Torvalds' , Arnd Bergmann Cc: Mark Rutland , Rich Felker , "linux-ia64@vger.kernel.org" , Linux-sh list , Peter Zijlstra , "BROADCOM NVRAM DRIVER , Max Filippov" , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , "QUALCOMM HEXAGON... " , Helge Deller , "the arch/x86 maintainers , Russell King - ARM Linux" , "linux-csky@vger.kernel.org" , Christoph Hellwig , SYNOPSYS ARC ARCHITECTURE , "open list:TENSILICA XTENSA PORT , Arnd Bergmann , Heiko Carstens (xtensa)" , linux-um , Richard Weinberger , linux-m68k , Openrisc , Greentime Hu , Stafford Horne , "Linux ARM , Michal Simek , Thomas Bogendoerfer" , Nick Hu , Parisc List , Linux-MM , Linux API , "Linux Kernel Mailing List , Dinh Nguyen" , "Eric W . Biederman" , alpha , Andrew Morton , linuxppc-dev , David Miller , Al Viro List-ID: RnJvbTogTGludXMgVG9ydmFsZHMNCj4gU2VudDogMTQgRmVicnVhcnkgMjAyMiAyMDoyNA0KPiA+ DQo+ID4geDg2LTY0IGhhcyBhbHdheXMoKikgdXNlZCBUQVNLX1NJWkVfTUFYIGZvciBhY2Nlc3Nf b2soKSwgYW5kIHRoZQ0KPiA+IGdldF91c2VyKCkgYXNzZW1ibGVyIGltcGxlbWVudGF0aW9uIGRv ZXMgdGhlIHNhbWUuDQo+IA0KPiBTaWRlIG5vdGU6IHdlIGNvdWxkIGp1c3QgY2hlY2sgdGhlIHNp Z24gYml0IGluc3RlYWQsIGFuZCBhdm9pZCBiaWcNCj4gY29uc3RhbnRzIHRoYXQgd2F5Lg0KDQpU aGUgY2hlYXAgdGVzdCBmb3IgbW9zdCA2NGJpdCBpcyAoYWRkciB8IHNpemUpID4+IDYyICE9IDAu DQoNCkkgZGlkIHNvbWUgdGVzdHMgbGFzdCB3ZWVrIGFuZCB0aGUgY29tcGlsZXJzIGNvcnJlY3Rs eSBvcHRpbWlzZQ0Kb3V0IGNvbnN0YW50IHNpemUuDQoNCkRvZXNuJ3Qgc3BhcmM2NCBzdGlsbCBu ZWVkIGEgd3JhcCB0ZXN0Pw0KT3IgaXMgdGhhdCBhc3N1bWVkIGJlY2F1c2UgdGhlcmUgaXMgYWx3 YXlzIGFuIHVubWFwcGVkIHBhZ2UNCmFuZCB0cmFuc2ZlciBhcmUgJ2FkZXF1YXRlbHknIGRvbmUg b24gaW5jcmVhc2luZyBhZGRyZXNzZXM/DQoNCglEYXZpZA0KDQotDQpSZWdpc3RlcmVkIEFkZHJl c3MgTGFrZXNpZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWlsdG9uIEtleW5lcywgTUsx IDFQVCwgVUsNClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMpDQo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Mon, 14 Feb 2022 22:13:34 +0000 Subject: [OpenRISC] [PATCH 04/14] x86: use more conventional access_ok() definition In-Reply-To: References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: openrisc@lists.librecores.org From: Linus Torvalds > Sent: 14 February 2022 20:24 > > > > x86-64 has always(*) used TASK_SIZE_MAX for access_ok(), and the > > get_user() assembler implementation does the same. > > Side note: we could just check the sign bit instead, and avoid big > constants that way. The cheap test for most 64bit is (addr | size) >> 62 != 0. I did some tests last week and the compilers correctly optimise out constant size. Doesn't sparc64 still need a wrap test? Or is that assumed because there is always an unmapped page and transfer are 'adequately' done on increasing addresses? David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 3D249C433F5 for ; Mon, 14 Feb 2022 22:14:16 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4JyJRB0PNZz3cXn for ; Tue, 15 Feb 2022 09:14:14 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=aculab.com (client-ip=185.58.86.151; helo=eu-smtp-delivery-151.mimecast.com; envelope-from=david.laight@aculab.com; receiver=) Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4JyJQb43tyz3bTZ for ; Tue, 15 Feb 2022 09:13:41 +1100 (AEDT) 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-3-0IuFZHXpM1-VcUsNfepTpQ-1; Mon, 14 Feb 2022 22:13:36 +0000 X-MC-Unique: 0IuFZHXpM1-VcUsNfepTpQ-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; Mon, 14 Feb 2022 22:13:34 +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; Mon, 14 Feb 2022 22:13:34 +0000 From: David Laight To: 'Linus Torvalds' , Arnd Bergmann Subject: RE: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Topic: [PATCH 04/14] x86: use more conventional access_ok() definition Thread-Index: AQHYIeHe9n+22PBgtUWxf89GrdwkK6yTmyQw Date: Mon, 14 Feb 2022 22:13:34 +0000 Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-5-arnd@kernel.org> 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Rich Felker , "linux-ia64@vger.kernel.org" , Linux-sh list , Peter Zijlstra , Linux Kernel Mailing List , Max Filippov , Guo Ren , sparclinux , linux-riscv , Will Deacon , Ard Biesheuvel , linux-arch , linux-s390 , Brian Cain , "open list:QUALCOMM HEXAGON..." , Helge Deller , the arch/x86 maintainers , Russell King - ARM Linux , "linux-csky@vger.kernel.org" , Christoph Hellwig , Christoph Hellwig , Ingo Molnar , Geert Uytterhoeven , "open list:SYNOPSYS ARC ARCHITECTURE" , "open list:TENSILICA XTENSA PORT \(xtensa\)" , Arnd Bergmann , Heiko Carstens , alpha , linux-um , linux-m68k , Openrisc , Greentime Hu , Stafford Horne , Linux ARM , Michal Simek , Thomas Bogendoerfer , Parisc List , Nick Hu , Linux-MM , Linux API , "open list:BROADCOM NVRAM DRIVER" , Dinh Nguyen , "Eric W . 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