From mboxrd@z Thu Jan 1 00:00:00 1970 From: Szabolcs Nagy Subject: Re: [PATCH v7 1/2] arm64: Define Documentation/arm64/tagged-address-abi.rst Date: Thu, 8 Aug 2019 16:30:01 +0000 Message-ID: References: <20190807155321.9648-1-catalin.marinas@arm.com> <20190807155321.9648-2-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190807155321.9648-2-catalin.marinas@arm.com> Content-Language: en-US Content-ID: <2416489F113EC049B7C1E80E7213516F@eurprd08.prod.outlook.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Catalin Marinas , "linux-arm-kernel@lists.infradead.org" Cc: "linux-arch@vger.kernel.org" , Vincenzo Frascino , "linux-doc@vger.kernel.org" , Andrey Konovalov , Kevin Brodsky , Will Deacon , Dave Hansen , nd List-Id: linux-arch.vger.kernel.org On 07/08/2019 16:53, Catalin Marinas wrote: > From: Vincenzo Frascino > > On arm64 the TCR_EL1.TBI0 bit has been always enabled hence > the userspace (EL0) is allowed to set a non-zero value in the > top byte but the resulting pointers are not allowed at the > user-kernel syscall ABI boundary. > > With the relaxed ABI proposed through this document, it is now possible > to pass tagged pointers to the syscalls, when these pointers are in > memory ranges obtained by an anonymous (MAP_ANONYMOUS) mmap(). description needs to be updated not to restrict tags to anon mmap. > +3. AArch64 Tagged Address ABI Exceptions > +----------------------------------------- > + > +The behaviour described in section 2, with particular reference to the > +acceptance by the syscalls of any valid tagged pointer, is not applicable > +to the following cases: > + > +- mmap() addr parameter. > + > +- mremap() new_address parameter. > + > +- prctl(PR_SET_MM, ``*``, ...) other than arg2 PR_SET_MM_MAP and > + PR_SET_MM_MAP_SIZE. > + > +- prctl(PR_SET_MM, PR_SET_MM_MAP{,_SIZE}, ...) struct prctl_mm_map fields. > + > +Any attempt to use non-zero tagged pointers will lead to undefined > +behaviour. i think that brk may be affected too by whatever that's causing problems in mmap. otherwise the text looks good to me. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr20066.outbound.protection.outlook.com ([40.107.2.66]:10816 "EHLO EUR02-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725535AbfHHQaT (ORCPT ); Thu, 8 Aug 2019 12:30:19 -0400 From: Szabolcs Nagy Subject: Re: [PATCH v7 1/2] arm64: Define Documentation/arm64/tagged-address-abi.rst Date: Thu, 8 Aug 2019 16:30:01 +0000 Message-ID: References: <20190807155321.9648-1-catalin.marinas@arm.com> <20190807155321.9648-2-catalin.marinas@arm.com> In-Reply-To: <20190807155321.9648-2-catalin.marinas@arm.com> Content-Language: en-US Content-Type: text/plain; charset="utf-8" Content-ID: <2416489F113EC049B7C1E80E7213516F@eurprd08.prod.outlook.com> Content-Transfer-Encoding: base64 MIME-Version: 1.0 Sender: linux-arch-owner@vger.kernel.org List-ID: To: Catalin Marinas , "linux-arm-kernel@lists.infradead.org" Cc: nd , Vincenzo Frascino , Will Deacon , Andrey Konovalov , Kevin Brodsky , "linux-doc@vger.kernel.org" , "linux-arch@vger.kernel.org" , Dave Hansen Message-ID: <20190808163001.KJ44I3Hkr2EquFKzyL-SFiZte_mUvpAahCFiEGHdlOw@z> T24gMDcvMDgvMjAxOSAxNjo1MywgQ2F0YWxpbiBNYXJpbmFzIHdyb3RlOg0KPiBGcm9tOiBWaW5j ZW56byBGcmFzY2lubyA8dmluY2Vuem8uZnJhc2Npbm9AYXJtLmNvbT4NCj4gDQo+IE9uIGFybTY0 IHRoZSBUQ1JfRUwxLlRCSTAgYml0IGhhcyBiZWVuIGFsd2F5cyBlbmFibGVkIGhlbmNlDQo+IHRo ZSB1c2Vyc3BhY2UgKEVMMCkgaXMgYWxsb3dlZCB0byBzZXQgYSBub24temVybyB2YWx1ZSBpbiB0 aGUNCj4gdG9wIGJ5dGUgYnV0IHRoZSByZXN1bHRpbmcgcG9pbnRlcnMgYXJlIG5vdCBhbGxvd2Vk IGF0IHRoZQ0KPiB1c2VyLWtlcm5lbCBzeXNjYWxsIEFCSSBib3VuZGFyeS4NCj4gDQo+IFdpdGgg dGhlIHJlbGF4ZWQgQUJJIHByb3Bvc2VkIHRocm91Z2ggdGhpcyBkb2N1bWVudCwgaXQgaXMgbm93 IHBvc3NpYmxlDQo+IHRvIHBhc3MgdGFnZ2VkIHBvaW50ZXJzIHRvIHRoZSBzeXNjYWxscywgd2hl biB0aGVzZSBwb2ludGVycyBhcmUgaW4NCj4gbWVtb3J5IHJhbmdlcyBvYnRhaW5lZCBieSBhbiBh bm9ueW1vdXMgKE1BUF9BTk9OWU1PVVMpIG1tYXAoKS4NCg0KZGVzY3JpcHRpb24gbmVlZHMgdG8g YmUgdXBkYXRlZCBub3QgdG8gcmVzdHJpY3QgdGFncw0KdG8gYW5vbiBtbWFwLg0KDQo+ICszLiBB QXJjaDY0IFRhZ2dlZCBBZGRyZXNzIEFCSSBFeGNlcHRpb25zDQo+ICstLS0tLS0tLS0tLS0tLS0t LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLQ0KPiArDQo+ICtUaGUgYmVoYXZpb3VyIGRlc2NyaWJl ZCBpbiBzZWN0aW9uIDIsIHdpdGggcGFydGljdWxhciByZWZlcmVuY2UgdG8gdGhlDQo+ICthY2Nl cHRhbmNlIGJ5IHRoZSBzeXNjYWxscyBvZiBhbnkgdmFsaWQgdGFnZ2VkIHBvaW50ZXIsIGlzIG5v dCBhcHBsaWNhYmxlDQo+ICt0byB0aGUgZm9sbG93aW5nIGNhc2VzOg0KPiArDQo+ICstIG1tYXAo KSBhZGRyIHBhcmFtZXRlci4NCj4gKw0KPiArLSBtcmVtYXAoKSBuZXdfYWRkcmVzcyBwYXJhbWV0 ZXIuDQo+ICsNCj4gKy0gcHJjdGwoUFJfU0VUX01NLCBgYCpgYCwgLi4uKSBvdGhlciB0aGFuIGFy ZzIgUFJfU0VUX01NX01BUCBhbmQNCj4gKyAgUFJfU0VUX01NX01BUF9TSVpFLg0KPiArDQo+ICst IHByY3RsKFBSX1NFVF9NTSwgUFJfU0VUX01NX01BUHssX1NJWkV9LCAuLi4pIHN0cnVjdCBwcmN0 bF9tbV9tYXAgZmllbGRzLg0KPiArDQo+ICtBbnkgYXR0ZW1wdCB0byB1c2Ugbm9uLXplcm8gdGFn Z2VkIHBvaW50ZXJzIHdpbGwgbGVhZCB0byB1bmRlZmluZWQNCj4gK2JlaGF2aW91ci4NCg0KaSB0 aGluayB0aGF0IGJyayBtYXkgYmUgYWZmZWN0ZWQgdG9vIGJ5IHdoYXRldmVyIHRoYXQncw0KY2F1 c2luZyBwcm9ibGVtcyBpbiBtbWFwLg0KDQpvdGhlcndpc2UgdGhlIHRleHQgbG9va3MgZ29vZCB0 byBtZS4NCg==