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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 BAF82C2BA83 for ; Wed, 12 Feb 2020 11:45:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 81D3520675 for ; Wed, 12 Feb 2020 11:45:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 81D3520675 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1725D6B0433; Wed, 12 Feb 2020 06:45:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 122876B0435; Wed, 12 Feb 2020 06:45:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 039036B0436; Wed, 12 Feb 2020 06:45:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id DC1016B0433 for ; Wed, 12 Feb 2020 06:45:22 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id A74868245571 for ; Wed, 12 Feb 2020 11:45:22 +0000 (UTC) X-FDA: 76481294484.26.kiss76_863a77e58b428 X-HE-Tag: kiss76_863a77e58b428 X-Filterd-Recvd-Size: 2375 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Wed, 12 Feb 2020 11:45:22 +0000 (UTC) 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 59E9A30E; Wed, 12 Feb 2020 03:45:21 -0800 (PST) Received: from arrakis.emea.arm.com (arrakis.cambridge.arm.com [10.1.196.71]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 09B723F68F; Wed, 12 Feb 2020 03:45:19 -0800 (PST) Date: Wed, 12 Feb 2020 11:45:17 +0000 From: Catalin Marinas To: Kevin Brodsky Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , Marc Zyngier , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Andrey Konovalov , linux-mm@kvack.org, linux-arch@vger.kernel.org Subject: Re: [PATCH 19/22] arm64: mte: Allow user control of the tag check mode via prctl() Message-ID: <20200212114517.GF488264@arrakis.emea.arm.com> References: <20191211184027.20130-1-catalin.marinas@arm.com> <20191211184027.20130-20-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Fri, Dec 27, 2019 at 02:34:32PM +0000, Kevin Brodsky wrote: > Not just related to this patch, but here goes. While trying to debug an > MTE-enabled process, I realised that there's no way to tell the tagged addr > / MTE thread configuration from outside of the thread. At this point I > thought it'd be really nice if this were to be exposed in /proc/pid, maybe > in /proc/pid/status. Unfortunately there seems to be no precedent for an > arch-specific feature to be exposed there. I guess a ptrace call would work > as well, although it wouldn't be as practical without using a debugger. There is proc_pid_arch_status(), currently only used by x86 to report the avx512 status. We could do the same on arm64 and provide information information on the MTE status, SVE configuration, ptrauth. I think this can be a separate patch covering all these. -- Catalin