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 4E061C3DA7D for ; Tue, 3 Jan 2023 16:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238248AbjACQvJ (ORCPT ); Tue, 3 Jan 2023 11:51:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233711AbjACQu6 (ORCPT ); Tue, 3 Jan 2023 11:50:58 -0500 Received: from wnew1-smtp.messagingengine.com (wnew1-smtp.messagingengine.com [64.147.123.26]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87AAC12D28; Tue, 3 Jan 2023 08:50:28 -0800 (PST) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailnew.west.internal (Postfix) with ESMTP id 36F072B06721; Tue, 3 Jan 2023 11:50:23 -0500 (EST) Received: from imap51 ([10.202.2.101]) by compute6.internal (MEProxy); Tue, 03 Jan 2023 11:50:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:date:date:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to; s=fm2; t=1672764622; x=1672771822; bh=OAEx+kWOpU s1ovkCOUPYt4BrguZtb4ZebjcqYHg4/yk=; b=SAmVbdnFaBzWfpnFGzV4NSDsrp w/oJNVKvqGJxgxv+5cuJf5nW1Un9vV0Dp+Wz/8PRNAPQi9a6E9iB6P7fPKvjIxDc sL4HDcHtwrl7pXHk7V3MgPQWqu05FxSbB9sUvpWN9KKGs4x8vL+qIY/u0O2fp32A WAqTXa3KI/HWcNdqPcB+rYggrEcH15MpJ6Rkc4JPKXgau/UtLCWzNDxTa3kwfqeV zzXlg1coYrCQvujOFEC7eWm3ZTrIXSENwnHXqfIt0HR4tRDATgdIYXJK/5Nklyc9 aK1RL7dvFw5nAF9DzxYqmKbi/kWMx9keHmBbHeA7s/EWyr+VxGNjwhtKapYA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:in-reply-to:message-id :mime-version:references:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; t=1672764622; x=1672771822; bh=OAEx+kWOpUs1ovkCOUPYt4BrguZt b4ZebjcqYHg4/yk=; b=Os1ym1lstngE1yum7vioqidaf0tpUcIIddLV9oaWSOfr Bp/LOs8s1eDc1lv7yge46iL+oTo/wMkxx27m9Yc6N3aV2TFIrYSkjiZdPQ8Dixm+ MdtzUXOxkrF8n3jv67bTVLyIeEpdtwhZZbr6DRy6eSsxHEeLTvrwGMCkx5wOQru3 LcNlUNWCaMJK5m1qqNpuLPnUa66cfWOJJRIOlVox9K7/RRqPZ9SJl0dYQTo66EU5 cPPwriRMEe+ZdKHvf4o8MaE+JiGSbpGlrJv8+wqaIVkBvWZfTB6lLcEQvdFquzkx fChHnH7XWHxMTXIIMydoHXwDKugKo6A7KVet7ij5Nw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvhedrjeeggdelfecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefofgggkfgjfhffhffvvefutgesthdtredtreertdenucfhrhhomhepfdetrhhn ugcuuegvrhhgmhgrnhhnfdcuoegrrhhnugesrghrnhgusgdruggvqeenucggtffrrghtth gvrhhnpefhfeehgfejkedugeeutdffveehheeugfehgeelleefudeluedtgfejffeihffh heenucffohhmrghinhepkhgvrhhnvghlrdhorhhgpdguvggsihgrnhdrohhrghenucevlh hushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegrrhhnugesrghr nhgusgdruggv X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id 465BAB60086; Tue, 3 Jan 2023 11:50:21 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.7.0-alpha0-1185-g841157300a-fm-20221208.002-g84115730 Mime-Version: 1.0 Message-Id: <8fea3494-1d1f-4f64-b525-279152cf430b@app.fastmail.com> In-Reply-To: References: <20221219153525.632521981@infradead.org> <20221219154119.154045458@infradead.org> Date: Tue, 03 Jan 2023 17:50:00 +0100 From: "Arnd Bergmann" To: "Mark Rutland" , "Peter Zijlstra" Cc: "Boqun Feng" , "Linus Torvalds" , "Jonathan Corbet" , "Will Deacon" , "Catalin Marinas" , dennis@kernel.org, "Tejun Heo" , "Christoph Lameter" , "Heiko Carstens" , gor@linux.ibm.com, "Alexander Gordeev" , borntraeger@linux.ibm.com, svens@linux.ibm.com, "Herbert Xu" , "David S . Miller" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Dave Hansen" , x86@kernel.org, "H. Peter Anvin" , joro@8bytes.org, suravee.suthikulpanit@amd.com, "Robin Murphy" , dwmw2@infradead.org, baolu.lu@linux.intel.com, "Pekka Enberg" , "David Rientjes" , "Joonsoo Kim" , "Andrew Morton" , "Vlastimil Babka" , "Roman Gushchin" , "Hyeonggon Yoo" <42.hyeyoo@gmail.com>, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-crypto@vger.kernel.org, iommu@lists.linux.dev, Linux-Arch Subject: Re: [RFC][PATCH 05/12] arch: Introduce arch_{,try_}_cmpxchg128{,_local}() Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Tue, Jan 3, 2023, at 17:19, Mark Rutland wrote: > On Tue, Jan 03, 2023 at 02:03:37PM +0000, Mark Rutland wrote: >> On Tue, Jan 03, 2023 at 01:25:35PM +0000, Mark Rutland wrote: >> > On Tue, Dec 20, 2022 at 12:08:16PM +0100, Peter Zijlstra wrote: >> ... makes GCC much happier: > >> ... I'll go check whether clang is happy with that, and how far back that can >> go, otherwise we'll need to blat the high half with a separate constaint that >> (ideally) doesn't end up allocating a pointless address register. > > Hmm... from the commit history it looks like GCC prior to 5.1 might not be > happy with that, but that *might* just be if we actually do arithmetic on the > value, and we might be ok just using it for memroy effects. I can't currently > get such an old GCC to run on my machines so I haven't been able to check. gcc-5.1 is the oldest (barely) supported compiler, the minimum was last raised from gcc-4.9 in linux-5.15. If only gcc-4.9 and older are affected, we're good on mainline but may still want a fix for stable kernels. I checked that the cross-compiler binaries from [1] still work, but I noticed that this version is missing the native aarch64-to-aarch64 compiler (x86 to aarch64 and vice versa are there), and you need to install libmpfr4 [2] as a dependency. The newer compilers (6.5.0 and up) don't have these problems. Arnd [1] https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/arm64/5.5.0/ [2] http://ftp.uk.debian.org/debian/pool/main/m/mpfr4/libmpfr4_3.1.5-1_arm64.deb