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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6B18FC88E72 for ; Thu, 17 Sep 2026 10:51:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=FvbLEQ+5qgNl0vRkjXPHqsEPk7oY6DEg8oRMHNxOtSc=; b=QZ/w9ycadbDwNW0vqq/vpzh64P I/ybiZ1dBX1mQ/J8pv+8wuh3D4D3nYVyAfq/kMAq5cASuMauGNnRSm3p84xQD11GVIiYZyjRcY0DL BpyrIOtyAKVSrpWbWuGkk3RXVcfe2/c+nkUsWcxE2O77xUWlKWd0ThblktYqRaAqhMDFb1qLQ8oaw K3BqqZar99I6bufoyg1FTg+0q80yUfhdDP19Zt2JNpDkC3ojG7fWwqARkXx1QW3vyuuRcmr9jQawV +ZkMykhWa6jWOGNs4uB3dNzEuPk6d7cWaqSx7gcf1XGqqXY4AYg5opqJaGmtLMK/XicCH9W86y/yJ ZccmCGxA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x79hr-0000000B8YL-3ZrH; Thu, 17 Sep 2026 10:51:07 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x79hp-0000000B8Xy-15rc for linux-arm-kernel@lists.infradead.org; Thu, 17 Sep 2026 10:51:06 +0000 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 97B191476; Thu, 17 Sep 2026 03:50:59 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B2D533F882; Thu, 17 Sep 2026 03:51:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789642263; bh=XihqMbgiW7kyP3lfZhBkDWHC5GYJp5plq+bKZoZZO64=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RtNfF25amyqFFOwy8f7Iwf2XNcgtv+nIar7eBklFC+H7xAzdIEqMy9x0nlPGgqPRB cJk9SAnVOKw5yit88ub9YsR0jRng8wnZMYVoikwQM+HrvrznRNZAqoMaF/uTPYGa02 tQe/QcLuEmF28RDLit3va2X5NLtfgxw0mBTlrlP8= Date: Thu, 17 Sep 2026 11:50:58 +0100 From: Mark Rutland To: =?utf-8?B?QW5kcsOp?= Almeida Cc: Catalin Marinas , Will Deacon , Thomas Gleixner , Mathieu Desnoyers , Sebastian Andrzej Siewior , Peter Zijlstra , Florian Weimer , Darren Hart , Ingo Molnar , Davidlohr Bueso , Arnd Bergmann , Uros Bizjak , Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, kernel-dev@igalia.com Subject: Re: [PATCH v8 4/4] arm64: vdso32: Implement __vdso_futex_robust_try_unlock() Message-ID: References: <20260821-tonyk-robust_arm-v8-0-077707b6f1c7@igalia.com> <20260821-tonyk-robust_arm-v8-4-077707b6f1c7@igalia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260917_035105_336613_F26A80D2 X-CRM114-Status: GOOD ( 15.79 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 16, 2026 at 10:11:01PM -0300, André Almeida wrote: > Em 16/09/2026 11:28, Mark Rutland escreveu: > > On Fri, Aug 21, 2026 at 06:50:45PM -0300, André Almeida wrote: > > > Based on aarch64 implementation, provide a 32 bit entry point for > > > this vDSO. > > > > > > In order to keep compatibility with arm64_futex_robust_unlock_get_pop(), > > > make sure to store the pop address at r2 and the compare result value > > > at r3. > > > > Before we add this to the compat vdso, we'll need to implement this on > > arch/arm/. > > > > Otherwise, my comments on the patch for the native vdso functions apply > > here too. > > Right, and the compat entry point at arch/arm64/ would point to the > __vdso_futex_robust_list32_try_unlock implementation at arch/arm/? So far we've had arm64 provide its own copy (which e.g. might use sequences relying on ARMv8+ instructions), so I think we'd do the same here. The key thing is that 32-bit tasks on arm64 should see the same ABI as native tasks on 32-bit arm. As there's a risk that 32-bit arm might have some ABI quirks (e.g. due to older processors), we don't want to enable features for compat tasks on arm64 before that's been implemented on 32-bit arm. Mark.