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 98EE4C433EF for ; Tue, 15 Feb 2022 10:39:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To: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=wnLfep+01Ra450gW40Wa2VAntEFu84hSZeItMknGxJA=; b=Thikeg6C+vHoYf bX0AQzmFf3ZCXMEQyIeWP7vfKMNSPTXqmxLX+wjHNdPuv81VTI4N4ejdcv04LqQATzkBOR1q7Cfvm iuqMldxPJ3oP6YTCQ7vwDjDVYADoULMVdAayaCoj0l+gr3JoZj0AV+MaRduPwhSB1rZwMo/rSM/jl x4PWccW3VgLG39LITWfVv2CVRMDFZmUmSAbluxdcSdolC3D9XrvzYxpYmLqStOq/76xisFRaEcyfh HFvD+h/C1q2eSMlETz4zq2YgtrDfBtkBg/yqGh+YKGAv91i6W7pwCuQkl6Wt5UTAunEY7FVR07kTk 4Y3X1qzrOZqHjrTbSG2Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJvEv-002KwT-QO; Tue, 15 Feb 2022 10:39:21 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nJvEs-002KuD-FT; Tue, 15 Feb 2022 10:39:19 +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 31E1E13D5; Tue, 15 Feb 2022 02:39:17 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.89.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4B7AE3F66F; Tue, 15 Feb 2022 02:39:10 -0800 (PST) Date: Tue, 15 Feb 2022 10:39:06 +0000 From: Mark Rutland To: Arnd Bergmann Cc: Ard Biesheuvel , 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 , 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 Subject: Re: [PATCH 08/14] arm64: simplify access_ok() Message-ID: References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-9-arnd@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220215_023918_616150_FD4E6A7D X-CRM114-Status: GOOD ( 16.92 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Feb 15, 2022 at 10:39:46AM +0100, Arnd Bergmann wrote: > 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 This would be an ABI change, e.g. for tasks without TIF_TAGGED_ADDR. I don't think we should change this as part of this series. Thanks, Mark. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv