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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 B98CCC2B9F8 for ; Tue, 25 May 2021 19:04:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2A24C61378 for ; Tue, 25 May 2021 19:04:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A24C61378 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8D5806B0036; Tue, 25 May 2021 15:04:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8AB026B006C; Tue, 25 May 2021 15:04:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 74CFC6B006E; Tue, 25 May 2021 15:04:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 40B726B0036 for ; Tue, 25 May 2021 15:04:07 -0400 (EDT) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C9EC482499A8 for ; Tue, 25 May 2021 19:04:06 +0000 (UTC) X-FDA: 78180678492.14.1B518D8 Received: from mail-io1-f51.google.com (mail-io1-f51.google.com [209.85.166.51]) by imf14.hostedemail.com (Postfix) with ESMTP id A7027C0042EA for ; Tue, 25 May 2021 19:03:59 +0000 (UTC) Received: by mail-io1-f51.google.com with SMTP id d25so20970863ioe.1 for ; Tue, 25 May 2021 12:04:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=a8KfzQLOAd7uDaZYELgyrbTQ/yuCXQtc51Q2W8qNwJE=; b=qCAMfOmVxX1GcSg02E1Z/zzCKgd08PNI4o38u1WXcLkwOk0j4gVIkjwS2lRDCu+IMu bfSHz6Ks0n1wKrFHTBz10bIiRBBBMVza6HFVmmGYs8AqrymWiaWkUoLAmr6MDsOdZR+C 4xrJVCKNTe/jpXBZRNN/m1ohLmVNax+yfQGY8T1tFUKf0h1jj63JGi/YhPxNfM8ECucj oJXgcPgMNQ/h774J2x2ULcJMszvG6HkpTb9RO66MQ19yR6mG/9IEv1DNrQ/QBzXf52BT cZ519DkQfehoceVTsNQJ5VTtn6LU7pT+q8v/qJs+l9swE0zkZf5FzmYivF/GPAEJ6gEn dyxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=a8KfzQLOAd7uDaZYELgyrbTQ/yuCXQtc51Q2W8qNwJE=; b=c9TMCeTjnhZPz7r/d0rlp4xQeU4aJCmokvdVpiPxGzpSOUHAuCUGBVeRE5uuTjtg+e +qIKV9rNqbdfitXTmWHIQZIGLce9Kd9Kc2YbPi9623rb/kYLr8GgWHNA01N4STYWcFVv dRCxJBLn/aYdNSeL5R1n6FhuIZa/uVgyRRQ0QeVaCe4uwdHz8NpfrR2jSLXszINOTFOD cr1ZOnxenHLrHmUb8uHl8ouTxiCjB8laopEcvKszyctDR/jenDM1FbDcWhxS29yvIQiT x3ETTjZRQ7RZYFdDLYTOJum4tnz9MGarsWnQzygKU8KgrKlNL0qTz7WZ2Mr29Zdmq1oP AA2g== X-Gm-Message-State: AOAM532RRIg14IB56FH8avR4fuIQ87n6/v6OTJ3oELJb+z+4ARUS6rLR Crim3W9IRPn5u0y1ghSRoM8op5Ol/vNTZq27VKS5Wg== X-Google-Smtp-Source: ABdhPJz+6V7Hli16pePTPYzXZdGaf8gtkmmt0Mb1uNVdGGG8WphNicYqQMKQmu1S94tR0l1fw5tZ5siTi0jW5cq7ISk= X-Received: by 2002:a5d:8996:: with SMTP id m22mr16536883iol.6.1621969445476; Tue, 25 May 2021 12:04:05 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Peter Collingbourne Date: Tue, 25 May 2021 12:03:53 -0700 Message-ID: Subject: Re: [PATCH v3 0/3] arm64: improve efficiency of setting tags for user pages To: Andrey Konovalov , Alexander Potapenko , Catalin Marinas , Vincenzo Frascino , Andrew Morton Cc: Evgenii Stepanov , Linux Memory Management List , Linux ARM , Marco Elver Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=qCAMfOmV; spf=pass (imf14.hostedemail.com: domain of pcc@google.com designates 209.85.166.51 as permitted sender) smtp.mailfrom=pcc@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: A7027C0042EA X-Stat-Signature: etf6bgdo7cmg8bffrfopajzpimbkshyb X-HE-Tag: 1621969439-361074 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 Wed, May 12, 2021 at 1:09 PM Peter Collingbourne wrote: > > Currently we can end up touching PROT_MTE user pages twice on fault > and once on unmap. On fault, with KASAN disabled we first clear data > and then set tags to 0, and with KASAN enabled we simultaneously > clear data and set tags to the KASAN random tag, and then set tags > again to 0. On unmap, we poison the page by setting tags, but this > is less likely to find a bug than poisoning kernel pages. > > This patch series fixes these inefficiencies by only touching the pages > once on fault using the DC GZVA instruction to clear both data and > tags, and providing the option to avoid poisoning user pages on free. > > Peter Collingbourne (3): > kasan: use separate (un)poison implementation for integrated init > arm64: mte: handle tags zeroing at page allocation time > kasan: allow freed user page poisoning to be disabled with HW tags Thanks Catalin for reviewing patch 2. Could someone on the KASAN side please take a look at patches 1 and 3? I imagine that we'll want this series to go in via the mm tree once it's ready. Peter