From mboxrd@z Thu Jan 1 00:00:00 1970 From: Szabolcs Nagy Subject: Re: [PATCH v7 0/2] arm64 tagged address ABI Date: Thu, 8 Aug 2019 09:32:28 +0000 Message-ID: <44bc76f2-e782-b3ac-5ba3-39ef59be6fe9@arm.com> References: <20190807155321.9648-1-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190807155321.9648-1-catalin.marinas@arm.com> Content-Language: en-US Content-ID: 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: > Hi, > > Thanks for the feedback so far. This is an updated series documenting > the AArch64 Tagged Address ABI as implemented by these patches: > > http://lkml.kernel.org/r/cover.1563904656.git.andreyknvl@google.com > > Version 6 of the documentation series is available here: > > http://lkml.kernel.org/r/20190725135044.24381-1-vincenzo.frascino@arm.com > > Changes in v7: > > - Dropped the MAP_PRIVATE requirements for tagged pointers for both > anonymous and file mappings. One reason is that we can't enforce such > restriction anyway. The other reason is that a future series > implementing support for the hardware MTE will detect > incompatibilities of the new PROT_MTE flag with various mmap() > options. OK. > - As a consequence of the above, I removed Szabolcs ack as I'm not sure > he's ok with the change. > > - Clarified the sysctl and prctl() interaction and reordered the > descriptions. > > - Reworded the prctl(PR_SET_MM) restrictions. > > - Removed the description of the tag preservation from the first patch > as it didn't really make sense (the syscall ABI has always preserved > all registers other than x0 on return to user). preservation is more interesting when a user pointer is passed to the kernel and later it is passed back to user space (e.g. set/get_robust_list, or sigaction where old handler pointer is returned), then the kernel may want to drop the tag to do something with the pointer, but user space may want it to be preserved. in principle segfault si_addr is a similar case when memory access via tagged pointer faults: currently the kernel does not preserve the tag. so i think it's interesting to know when exactly the kernel preserves the tags, but it may not be easy to document in a generic way. > > - s/ARM64/AArch64/ for consistency with the tagged-pointers.rst > document. > > - Other minor rewordings. > > Vincenzo Frascino (2): > arm64: Define Documentation/arm64/tagged-address-abi.rst > arm64: Relax Documentation/arm64/tagged-pointers.rst > > Documentation/arm64/tagged-address-abi.rst | 151 +++++++++++++++++++++ > Documentation/arm64/tagged-pointers.rst | 23 +++- > 2 files changed, 167 insertions(+), 7 deletions(-) > create mode 100644 Documentation/arm64/tagged-address-abi.rst > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr70050.outbound.protection.outlook.com ([40.107.7.50]:1601 "EHLO EUR04-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732076AbfHHJcp (ORCPT ); Thu, 8 Aug 2019 05:32:45 -0400 From: Szabolcs Nagy Subject: Re: [PATCH v7 0/2] arm64 tagged address ABI Date: Thu, 8 Aug 2019 09:32:28 +0000 Message-ID: <44bc76f2-e782-b3ac-5ba3-39ef59be6fe9@arm.com> References: <20190807155321.9648-1-catalin.marinas@arm.com> In-Reply-To: <20190807155321.9648-1-catalin.marinas@arm.com> Content-Language: en-US Content-Type: text/plain; charset="utf-8" Content-ID: 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: <20190808093228.jq5VAQafeKVfHVf0wKb6ZbMhWBoU1ksTkYWlcv3q_No@z> T24gMDcvMDgvMjAxOSAxNjo1MywgQ2F0YWxpbiBNYXJpbmFzIHdyb3RlOg0KPiBIaSwNCj4gDQo+ IFRoYW5rcyBmb3IgdGhlIGZlZWRiYWNrIHNvIGZhci4gVGhpcyBpcyBhbiB1cGRhdGVkIHNlcmll cyBkb2N1bWVudGluZw0KPiB0aGUgQUFyY2g2NCBUYWdnZWQgQWRkcmVzcyBBQkkgYXMgaW1wbGVt ZW50ZWQgYnkgdGhlc2UgcGF0Y2hlczoNCj4gDQo+IGh0dHA6Ly9sa21sLmtlcm5lbC5vcmcvci9j b3Zlci4xNTYzOTA0NjU2LmdpdC5hbmRyZXlrbnZsQGdvb2dsZS5jb20NCj4gDQo+IFZlcnNpb24g NiBvZiB0aGUgZG9jdW1lbnRhdGlvbiBzZXJpZXMgaXMgYXZhaWxhYmxlIGhlcmU6DQo+IA0KPiBo dHRwOi8vbGttbC5rZXJuZWwub3JnL3IvMjAxOTA3MjUxMzUwNDQuMjQzODEtMS12aW5jZW56by5m cmFzY2lub0Bhcm0uY29tDQo+IA0KPiBDaGFuZ2VzIGluIHY3Og0KPiANCj4gLSBEcm9wcGVkIHRo ZSBNQVBfUFJJVkFURSByZXF1aXJlbWVudHMgZm9yIHRhZ2dlZCBwb2ludGVycyBmb3IgYm90aA0K PiAgIGFub255bW91cyBhbmQgZmlsZSBtYXBwaW5ncy4gT25lIHJlYXNvbiBpcyB0aGF0IHdlIGNh bid0IGVuZm9yY2Ugc3VjaA0KPiAgIHJlc3RyaWN0aW9uIGFueXdheS4gVGhlIG90aGVyIHJlYXNv biBpcyB0aGF0IGEgZnV0dXJlIHNlcmllcw0KPiAgIGltcGxlbWVudGluZyBzdXBwb3J0IGZvciB0 aGUgaGFyZHdhcmUgTVRFIHdpbGwgZGV0ZWN0DQo+ICAgaW5jb21wYXRpYmlsaXRpZXMgb2YgdGhl IG5ldyBQUk9UX01URSBmbGFnIHdpdGggdmFyaW91cyBtbWFwKCkNCj4gICBvcHRpb25zLg0KDQpP Sy4NCg0KPiAtIEFzIGEgY29uc2VxdWVuY2Ugb2YgdGhlIGFib3ZlLCBJIHJlbW92ZWQgU3phYm9s Y3MgYWNrIGFzIEknbSBub3Qgc3VyZQ0KPiAgIGhlJ3Mgb2sgd2l0aCB0aGUgY2hhbmdlLg0KPiAN Cj4gLSBDbGFyaWZpZWQgdGhlIHN5c2N0bCBhbmQgcHJjdGwoKSBpbnRlcmFjdGlvbiBhbmQgcmVv cmRlcmVkIHRoZQ0KPiAgIGRlc2NyaXB0aW9ucy4NCj4gDQo+IC0gUmV3b3JkZWQgdGhlIHByY3Rs KFBSX1NFVF9NTSkgcmVzdHJpY3Rpb25zLg0KPiANCj4gLSBSZW1vdmVkIHRoZSBkZXNjcmlwdGlv biBvZiB0aGUgdGFnIHByZXNlcnZhdGlvbiBmcm9tIHRoZSBmaXJzdCBwYXRjaA0KPiAgIGFzIGl0 IGRpZG4ndCByZWFsbHkgbWFrZSBzZW5zZSAodGhlIHN5c2NhbGwgQUJJIGhhcyBhbHdheXMgcHJl c2VydmVkDQo+ICAgYWxsIHJlZ2lzdGVycyBvdGhlciB0aGFuIHgwIG9uIHJldHVybiB0byB1c2Vy KS4NCg0KcHJlc2VydmF0aW9uIGlzIG1vcmUgaW50ZXJlc3Rpbmcgd2hlbiBhIHVzZXIgcG9pbnRl cg0KaXMgcGFzc2VkIHRvIHRoZSBrZXJuZWwgYW5kIGxhdGVyIGl0IGlzIHBhc3NlZCBiYWNrDQp0 byB1c2VyIHNwYWNlIChlLmcuIHNldC9nZXRfcm9idXN0X2xpc3QsIG9yIHNpZ2FjdGlvbg0Kd2hl cmUgb2xkIGhhbmRsZXIgcG9pbnRlciBpcyByZXR1cm5lZCksIHRoZW4gdGhlDQprZXJuZWwgbWF5 IHdhbnQgdG8gZHJvcCB0aGUgdGFnIHRvIGRvIHNvbWV0aGluZyB3aXRoDQp0aGUgcG9pbnRlciwg YnV0IHVzZXIgc3BhY2UgbWF5IHdhbnQgaXQgdG8gYmUgcHJlc2VydmVkLg0KDQppbiBwcmluY2lw bGUgc2VnZmF1bHQgc2lfYWRkciBpcyBhIHNpbWlsYXIgY2FzZSB3aGVuDQptZW1vcnkgYWNjZXNz IHZpYSB0YWdnZWQgcG9pbnRlciBmYXVsdHM6IGN1cnJlbnRseQ0KdGhlIGtlcm5lbCBkb2VzIG5v dCBwcmVzZXJ2ZSB0aGUgdGFnLg0KDQpzbyBpIHRoaW5rIGl0J3MgaW50ZXJlc3RpbmcgdG8ga25v dyB3aGVuIGV4YWN0bHkgdGhlDQprZXJuZWwgcHJlc2VydmVzIHRoZSB0YWdzLCBidXQgaXQgbWF5 IG5vdCBiZSBlYXN5IHRvDQpkb2N1bWVudCBpbiBhIGdlbmVyaWMgd2F5Lg0KDQo+IA0KPiAtIHMv QVJNNjQvQUFyY2g2NC8gZm9yIGNvbnNpc3RlbmN5IHdpdGggdGhlIHRhZ2dlZC1wb2ludGVycy5y c3QNCj4gICBkb2N1bWVudC4NCj4gDQo+IC0gT3RoZXIgbWlub3IgcmV3b3JkaW5ncy4NCj4gDQo+ IFZpbmNlbnpvIEZyYXNjaW5vICgyKToNCj4gICBhcm02NDogRGVmaW5lIERvY3VtZW50YXRpb24v YXJtNjQvdGFnZ2VkLWFkZHJlc3MtYWJpLnJzdA0KPiAgIGFybTY0OiBSZWxheCBEb2N1bWVudGF0 aW9uL2FybTY0L3RhZ2dlZC1wb2ludGVycy5yc3QNCj4gDQo+ICBEb2N1bWVudGF0aW9uL2FybTY0 L3RhZ2dlZC1hZGRyZXNzLWFiaS5yc3QgfCAxNTEgKysrKysrKysrKysrKysrKysrKysrDQo+ICBE b2N1bWVudGF0aW9uL2FybTY0L3RhZ2dlZC1wb2ludGVycy5yc3QgICAgfCAgMjMgKysrLQ0KPiAg MiBmaWxlcyBjaGFuZ2VkLCAxNjcgaW5zZXJ0aW9ucygrKSwgNyBkZWxldGlvbnMoLSkNCj4gIGNy ZWF0ZSBtb2RlIDEwMDY0NCBEb2N1bWVudGF0aW9uL2FybTY0L3RhZ2dlZC1hZGRyZXNzLWFiaS5y c3QNCj4gDQoNCg==