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 582A8C19F2D for ; Tue, 9 Aug 2022 08:52:06 +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:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=afcdMWBB6Ld3Tein8wND5sVJRRiLrz8P47as+EpAkgo=; b=lNerpxt0hU5r4A wIoHVGdVgxAoGoQgOoYZ433c7swI/7VCCIN9PZOx0ArMUQV+TEW7x7q0yR/y1md+hhWuKkgLcbO8U WODh7/SRjUIsn9XmwQviE490WgmZAkVG4kFU/vy1D8ImQ1Odk2Mt6Zf7v1VjnApkAwO8VIzk9o4qR tbdf25F79oSLGKve5fgv1ynZ5wxjELEhCyuMaP89kKlAdXmoNG6+gzOrrwbCk8n1tHqjTF93W0w8m daryiCiS1lGhZ49KoWiYzDymxkwV9tTbIVMlO3nvgfgfbHmjxouK/2RI2PlIgw+o1MGzaR0GPoKZv snqRL/QFEWZOoPrJ2X/Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLKx4-002qy2-D4; Tue, 09 Aug 2022 08:51:02 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLKx0-002qxI-WB for linux-arm-kernel@lists.infradead.org; Tue, 09 Aug 2022 08:51:00 +0000 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 30BB260B4A; Tue, 9 Aug 2022 08:50:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80EFEC433C1; Tue, 9 Aug 2022 08:50:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660035057; bh=evTfIp15YyJmRvR5HorDzyJW/SaBilfmMUYg1BqmHzQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gBG9lyUoGhtkq9EO2+XPT+f/AbSBG6qLiWuHLpcsGpA+/rqd3it0dW2DA/IIdR1DF qOzaAzwYnoAbPzi+C7mAAK6iiMdcCG2VFq+NDv0oGv1iMf2TmBXFJZs0gzQcT4pjN4 qrwweEaKhTtNGNkz/dQUNKbCQ2f0ZB/hRgVuUZuc2hoI7aYXaijW8EOBNvvLo90Ckl 19oEF+gEdsPsZjXrgR0VPRBgaWY46A8BEdLmfeLOMNZJ5QObSgqtGaa5RUzVxqxOqb 42FcQ5J+69I1CKOXAgCJIe/uGZj5h+qVYXjjJT2jB9QSRQMEB/vKGy/jLfayLAP3ji usM04TTSS14nw== Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1oLKwx-001s6n-9T; Tue, 09 Aug 2022 09:50:55 +0100 Date: Tue, 09 Aug 2022 09:50:55 +0100 Message-ID: <875yj1x0k0.wl-maz@kernel.org> From: Marc Zyngier To: Evgenii Stepanov Cc: Catalin Marinas , Will Deacon , Peter Collingbourne , Vincenzo Frascino , Andrey Konovalov , Mark Brown , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mte: Follow arm64.nomte override in MMU setup. In-Reply-To: <20220805214734.1937451-1-eugenis@google.com> References: <20220805214734.1937451-1-eugenis@google.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: eugenis@google.com, catalin.marinas@arm.com, will@kernel.org, pcc@google.com, vincenzo.frascino@arm.com, andreyknvl@gmail.com, broonie@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220809_015059_091402_F7CD671F X-CRM114-Status: GOOD ( 19.74 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 05 Aug 2022 22:47:34 +0100, Evgenii Stepanov wrote: > > The current code sets up the memory attribute for Normal Tagged memory > in MAIR_EL1 whenever MTE is supported according to AA64PFR1.MTE without > taking arm64.nomte command line option into account. > > This breaks when tag pages are reused as regular memory, as direct > access to such pages through the linear map may create an invalid DRAM > address (tags-of-tags). How comes such memory is being used? How comes it is in the linear map? arm64.nomte is affecting the use of MTE feature on the platform. It doesn't guard the use of a MTE carve-out, and doesn't allow it to be used in any shape or form. To use this memory, you should remove the MTE configuration altogether, as you cannot infer what the CPU is doing with it. M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel