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 05877C43334 for ; Thu, 21 Jul 2022 15:25:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229620AbiGUPZ2 (ORCPT ); Thu, 21 Jul 2022 11:25:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229511AbiGUPZ2 (ORCPT ); Thu, 21 Jul 2022 11:25:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52D8047B95 for ; Thu, 21 Jul 2022 08:25:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 00C61B82588 for ; Thu, 21 Jul 2022 15:25:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D510BC3411E; Thu, 21 Jul 2022 15:25:21 +0000 (UTC) Date: Thu, 21 Jul 2022 16:25:17 +0100 From: Catalin Marinas To: Mark Brown Cc: Will Deacon , Shuah Khan , Marc Zyngier , Mark Rutland , Zhang Lei , linux-kselftest@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v1 0/3] arm64/sve: Document our actual SVE syscall ABI Message-ID: References: <20220720205013.890942-1-broonie@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220720205013.890942-1-broonie@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Wed, Jul 20, 2022 at 09:50:10PM +0100, Mark Brown wrote: > Currently our SVE syscall ABI documentation does not reflect the actual > implemented ABI, it says that register state not shared with FPSIMD > becomes undefined on syscall when in reality we always clear it. Since > changing this would cause a change in the observed kernel behaviour > there is a substantial desire to avoid taking advantage of the > documented ABI so instead let's document what we actually do so it's > clear that it is in reality an ABI. > > There has been some pushback on tightening the documentation in the past > but it is hard to see who that helps, it makes the implementation > decisions less clear and makes it harder for people to discover and make > use of the actual ABI. The main practical concern is that qemu's user > mode does not currently flush the registers. > > Mark Brown (3): > kselftest/arm64: Correct buffer allocation for SVE Z registers > arm64/sve: Document our actual ABI for clearing registers on syscall > kselftest/arm64: Enforce actual ABI for SVE syscalls For the series: Acked-by: Catalin Marinas