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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D02DFC61DA3 for ; Thu, 26 Jan 2023 11:15:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2480B6B0071; Thu, 26 Jan 2023 06:15:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1F8D66B0072; Thu, 26 Jan 2023 06:15:53 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 09A668E0001; Thu, 26 Jan 2023 06:15:53 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id ED9F06B0071 for ; Thu, 26 Jan 2023 06:15:52 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id B51C4AB111 for ; Thu, 26 Jan 2023 11:15:52 +0000 (UTC) X-FDA: 80396695344.22.3B5ED5E Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf03.hostedemail.com (Postfix) with ESMTP id 9CCB120017 for ; Thu, 26 Jan 2023 11:15:50 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf03.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1674731751; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WzK5SCFmLGevmA0/XfwOW0SJBEUmGOPYqCDHZ7DIQcU=; b=ne+uJ+Tn5Og31xFnr2tJmzL27CjJ9KrhTHAOb18HFUSMwVRT8yie0PwxGrKIyraAQgdj6p AqNGv5Fp8eNcGjQcRMIx7PqO0Gf/7XeyGIQSQ0EESUEqNF3UiLPO4TSHL9rqtjwYdOn12Q EeBFEReZcQb6M5+PQgxyqfQNOdIrJvE= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf03.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1674731751; a=rsa-sha256; cv=none; b=M7ql3zuFdPxbrK2xE3OLHchbaei5q3NtnleKtdiQJyy8IpBXOwBAV/qN3XOurfxOkLyIDQ JGjlrNCRpmE5beBQhIzdYJteuu88zRvZJwLgjp+mKp2Z7XvbRnJoQjw7vcOk6gF6iElEpX Rfs2HguSL0SedWDk8M26Qf/IPe9xf4g= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 32F024B3; Thu, 26 Jan 2023 03:16:31 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.10.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 402733F71E; Thu, 26 Jan 2023 03:15:40 -0800 (PST) Date: Thu, 26 Jan 2023 11:15:37 +0000 From: Mark Rutland To: Jules Maselbas Cc: Yann Sionneau , Arnd Bergmann , Jonathan Corbet , Thomas Gleixner , Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Will Deacon , Peter Zijlstra , Boqun Feng , Eric Biederman , Kees Cook , Oleg Nesterov , Ingo Molnar , Waiman Long , "Aneesh Kumar K.V" , Andrew Morton , Nick Piggin , Paul Moore , Eric Paris , Christian Brauner , Paul Walmsley , Palmer Dabbelt , Albert Ou , Guillaume Thouvenin , Clement Leger , Vincent Chardon , Marc =?utf-8?B?UG91bGhpw6hz?= , Julian Vetter , Samuel Jones , Ashley Lesdalons , Thomas Costis , Marius Gligor , Jonathan Borne , Julien Villette , Luc Michel , Louis Morhet , Julien Hascoet , Jean-Christophe Pince , Guillaume Missonnier , Alex Michon , Huacai Chen , WANG Xuerui , Shaokun Zhang , John Garry , Guangbin Huang , Bharat Bhushan , Bibo Mao , Atish Patra , "Jason A. Donenfeld" , Qi Liu , Jiaxun Yang , Catalin Marinas , Mark Brown , Janosch Frank , Alexey Dobriyan , Benjamin Mugnier , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-audit@redhat.com, linux-riscv@lists.infradead.org, bpf@vger.kernel.org Subject: Re: [RFC PATCH v2 11/31] kvx: Add atomic/locking headers Message-ID: References: <20230120141002.2442-1-ysionneau@kalray.eu> <20230120141002.2442-12-ysionneau@kalray.eu> <20230126095720.GF5952@tellis.lin.mbt.kalray.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230126095720.GF5952@tellis.lin.mbt.kalray.eu> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9CCB120017 X-Stat-Signature: cs61bwii5thus49cynr3net8xgoembwg X-Rspam-User: X-HE-Tag: 1674731750-100504 X-HE-Meta: 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 gQPDUBCo Q/I5RKR8I4wSAGaos9sj4T61NuX3unB5YaBbOlucTHsJz4H1kSGVNayrGJL7KSnolw/2+V64uoLwzpyXYNPj2ceVYfpbrFTCFhqdg7202M0c4b2LC/jt7O3hM7iTsnG7XBzJah0z1+lzVmO/tCXVA3gqUdwIh4bPP723kbxvlhEMtbodxnRWYD7+oKsgHPLhN+IQ2o2PRyWT9GioW+OVhvWrDYKhvlz3YdAFMbz0EUWgwjseLOoF6mOIWXa7J6YjveTu1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Jules, On Thu, Jan 26, 2023 at 10:57:20AM +0100, Jules Maselbas wrote: > Hi Mark, > > On Fri, Jan 20, 2023 at 03:18:48PM +0000, Mark Rutland wrote: > > On Fri, Jan 20, 2023 at 03:09:42PM +0100, Yann Sionneau wrote: > > > +#define ATOMIC64_RETURN_OP(op, c_op) \ > > > +static inline long arch_atomic64_##op##_return(long i, atomic64_t *v) \ > > > +{ \ > > > + long new, old, ret; \ > > > + \ > > > + do { \ > > > + old = v->counter; \ > > > > This should be arch_atomic64_read(v), in order to avoid the potential for the > > compiler to replay the access and introduce ABA races and other such problems. > Thanks for the suggestion, this will be into v3. > > > For details, see: > > > > https://lore.kernel.org/lkml/Y70SWXHDmOc3RhMd@osiris/ > > https://lore.kernel.org/lkml/Y71LoCIl+IFdy9D8@FVFF77S0Q05N/ > > > > I see that the generic 32-bit atomic code suffers from that issue, and we > > should fix it. > I took a look at the generic 32-bit atomic, but I am unsure if this > needs to be done for both the SMP and non-SMP implementations. But I > can send a first patch and we can discuss from there. Sounds good to me; thanks! [...] > > > +static inline int arch_atomic_add_return(int i, atomic_t *v) > > > +{ > > > + int new, old, ret; > > > + > > > + do { > > > + old = v->counter; > > > > Likewise, arch_atomic64_read(v) here. > ack, this will bt arch_atomic_read(v) here since this is not atomic64_t > here. Ah, yes, my bad! Thanks, Mark.