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 AA57BC433F5 for ; Tue, 15 Feb 2022 09:40:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 459956B0078; Tue, 15 Feb 2022 04:40:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 409366B007D; Tue, 15 Feb 2022 04:40:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F8936B007E; Tue, 15 Feb 2022 04:40:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 217916B0078 for ; Tue, 15 Feb 2022 04:40:07 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DB6A48249980 for ; Tue, 15 Feb 2022 09:40:06 +0000 (UTC) X-FDA: 79144518012.19.B6A3350 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf09.hostedemail.com (Postfix) with ESMTP id 61B64140007 for ; Tue, 15 Feb 2022 09:40:06 +0000 (UTC) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 881EE6102E for ; Tue, 15 Feb 2022 09:40:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 514C5C340F7 for ; Tue, 15 Feb 2022 09:40:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644918004; bh=hv8AUuEMkapI1zY2x6Wj+fHd7ew8TaKYgsOBPTPrxmw=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=Qgz5FlPpKWsWGCSKlOreQeA49RzB47Yb61DpdQGkSqCvpQXhd/1xrVzA6HxgVkOAv HM/bWEouCkOrFRfLVSWs2TAF8Lvnm82Q7ljXZwaQBoSUgr63Phu8Xh5sdVnTyJI/ON lHIubRtLqY287IV/RrnG/iEcxILMQsa62F1uuyYy08GpnMfCYeG+01yyQZZn7UnJv7 021LqbfWi1zld4k8/8Wmx6fnGfR5no+iR4l8Y+N7e700ePaO67g4IaN0y0Orgs7STR gYOAdpNAvnxBHFJPJ1WrXSLgaxHaPAb+pRZVWsShzWY/LNUX3cgIy9+U52JoF4j03G HEN4j4yjmnzVQ== Received: by mail-wm1-f52.google.com with SMTP id k127-20020a1ca185000000b0037bc4be8713so1032078wme.3 for ; Tue, 15 Feb 2022 01:40:04 -0800 (PST) X-Gm-Message-State: AOAM533HVzLSEt7qMkN9Lef63SMicz3TTRS5MLLoXmKztaizcHENCYVS ui+n/9zbumTKvFZl54mAzkiRkUQMmmXeUUfgTLg= X-Google-Smtp-Source: ABdhPJxpFSyo2tIfVZXx6xnWqAN7kXzL0SfiKGeaqLH7fIF3GRmujo8Iug1QC1Z1ypgNgRnGoRSGx0exr14yXtWS6QY= X-Received: by 2002:a05:600c:1d27:b0:37c:74bb:2b4d with SMTP id l39-20020a05600c1d2700b0037c74bb2b4dmr2314325wms.82.1644918002508; Tue, 15 Feb 2022 01:40:02 -0800 (PST) MIME-Version: 1.0 References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-9-arnd@kernel.org> In-Reply-To: From: Arnd Bergmann Date: Tue, 15 Feb 2022 10:39:46 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 08/14] arm64: simplify access_ok() To: Ard Biesheuvel Cc: Linus Torvalds , Christoph Hellwig , linux-arch , Linux Memory Management List , Linux API , Arnd Bergmann , Linux Kernel Mailing List , Russell King , Will Deacon , Guo Ren , Brian Cain , Geert Uytterhoeven , Michal Simek , Thomas Bogendoerfer , Nick Hu , Greentime Hu , Dinh Nguyen , Stafford Horne , Helge Deller , Michael Ellerman , Peter Zijlstra , Ingo Molnar , Mark Rutland , Heiko Carstens , Rich Felker , "David S. Miller" , Richard Weinberger , X86 ML , Max Filippov , "Eric W. Biederman" , Andrew Morton , alpha , "open list:SYNOPSYS ARC ARCHITECTURE" , Linux ARM , linux-csky@vger.kernel.org, "open list:QUALCOMM HEXAGON..." , linux-ia64@vger.kernel.org, linux-m68k , "open list:MIPS" , Openrisc , "open list:PARISC ARCHITECTURE" , "open list:LINUX FOR POWERPC (32-BIT AND 64-BIT)" , linux-riscv , "open list:S390" , Linux-sh list , "open list:SPARC + UltraSPARC (sparc/sparc64)" , linux-um , "open list:TENSILICA XTENSA PORT (xtensa)" , Robin Murphy Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Qgz5FlPp; spf=pass (imf09.hostedemail.com: domain of arnd@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=arnd@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam07 X-Rspam-User: X-Rspamd-Queue-Id: 61B64140007 X-Stat-Signature: 9j4j3d89bkp4a9igd981wy6aft73z99x X-HE-Tag: 1644918006-536074 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: On Tue, Feb 15, 2022 at 10:21 AM Ard Biesheuvel wrote: > On Tue, 15 Feb 2022 at 10:13, Arnd Bergmann wrote: > > arm64 also has this leading up to the range check, and I think we'd no > longer need it: > > if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) && > (current->flags & PF_KTHREAD || test_thread_flag(TIF_TAGGED_ADDR))) > addr = untagged_addr(addr); I suspect the expensive part here is checking the two flags, as untagged_addr() seems to always just add a sbfx instruction. Would this work? #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI #define access_ok(ptr, size) __access_ok(untagged_addr(ptr), (size)) #else // the else path is the default, this can be left out. #define access_ok(ptr, size) __access_ok((ptr), (size)) #endif Arnd