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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEBB0C433E1 for ; Wed, 27 May 2020 07:47:07 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id BFD8E208B8 for ; Wed, 27 May 2020 07:47:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lir+Dfj+"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="LVeFzpVd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BFD8E208B8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject: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=f4wHYUEtYqJXnjd16D32GPRmw6Qz+LcGpTWRgD31TQ4=; b=lir+Dfj+xOAQyG Gr6XTQ/ePOWgx+JIywdEmdLX19NMOCENpjeiIuPMPVTHkMMMai45f5aVP6kZi5vtATnt2i7zeQQHf SZHi51mXO4kvHtGBOIUEu2EAsls1wd9SFtAlntJHJpSzu1Aq2bH6w3gyrR/h+Noo3j+8Bgusdcnv0 2q127HohG25+Ls86YgYIA0hpIYsUeKKFr2dQW3nNuWQXHhjUvmj2E5C2P0TaELQYqDG7mZpJAkATJ n94ZnI4EPBQHeI4p2qjOOFXI8oBHKAF31hbB6XNoDDqqPLt9zpo5hNyW686zJMmOjQZMh6b78P88K PRCvFTV9cFMroe9k0CvA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdqmJ-0002jH-3D; Wed, 27 May 2020 07:47:07 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdqmG-0002iq-9A for linux-arm-kernel@lists.infradead.org; Wed, 27 May 2020 07:47:05 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4A0BD207CB; Wed, 27 May 2020 07:47:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590565624; bh=/FVQ3sLZUY/KzEKvgBXodRAdsyRqYRRArkYuCnMkydY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LVeFzpVdK/UfgPBIOmXoKNIzgx0gyeybY/yzjW9JfmshAD076tdIm8WEbWr9uII4S WXSdBD994NaKD8njjZAuYD4+sQJyHg9UtzIEBh5m8MWiUyZS/QNILopeSK3OP2I3IP FABRqUXF/55oL2QMxAZ5l3ouZLJiePenMtgCn6/c= Date: Wed, 27 May 2020 08:46:59 +0100 From: Will Deacon To: Catalin Marinas Subject: Re: [PATCH v4 15/26] arm64: mte: Allow user control of the tag check mode via prctl() Message-ID: <20200527074658.GB9887@willie-the-truck> References: <20200515171612.1020-1-catalin.marinas@arm.com> <20200515171612.1020-16-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200515171612.1020-16-catalin.marinas@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200527_004704_338940_B387C766 X-CRM114-Status: GOOD ( 18.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , linux-mm@kvack.org, Vincenzo Frascino , Peter Collingbourne , Dave P Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, May 15, 2020 at 06:16:01PM +0100, Catalin Marinas wrote: > By default, even if PROT_MTE is set on a memory range, there is no tag > check fault reporting (SIGSEGV). Introduce a set of option to the > exiting prctl(PR_SET_TAGGED_ADDR_CTRL) to allow user control of the tag > check fault mode: > > PR_MTE_TCF_NONE - no reporting (default) > PR_MTE_TCF_SYNC - synchronous tag check fault reporting > PR_MTE_TCF_ASYNC - asynchronous tag check fault reporting > > These options translate into the corresponding SCTLR_EL1.TCF0 bitfield, > context-switched by the kernel. Note that uaccess done by the kernel is > not checked and cannot be configured by the user. > > Signed-off-by: Catalin Marinas > Cc: Will Deacon > --- > > Notes: > v3: > - Use SCTLR_EL1_TCF0_NONE instead of 0 for consistency. > - Move mte_thread_switch() in this patch from an earlier one. In > addition, it is called after the dsb() in __switch_to() so that any > asynchronous tag check faults have been registered in the TFSR_EL1 > registers (to be added with the in-kernel MTE support. > > v2: > - Handle SCTLR_EL1_TCF0_NONE explicitly for consistency with PR_MTE_TCF_NONE. > - Fix SCTLR_EL1 register setting in flush_mte_state() (thanks to Peter > Collingbourne). > - Added ISB to update_sctlr_el1_tcf0() since, with the latest > architecture update/fix, the TCF0 field is used by the uaccess > routines. > > arch/arm64/include/asm/mte.h | 14 ++++++ > arch/arm64/include/asm/processor.h | 3 ++ > arch/arm64/kernel/mte.c | 77 ++++++++++++++++++++++++++++++ > arch/arm64/kernel/process.c | 26 ++++++++-- > include/uapi/linux/prctl.h | 6 +++ > 5 files changed, 123 insertions(+), 3 deletions(-) Dave is working on man pages for prctl() (and I think also ptrace). I think it would be /very/ useful for us to have some RFC patches on top of his work adding documentation for the MTE interactions, as we found some other minor issues/inconsistencies as a direct result of writing and reviewing the man page for our existing interfaces. Cheers, Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel