From patchwork Wed Jun 20 15:24:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10477739 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9870960230 for ; Wed, 20 Jun 2018 15:25:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 87A4E28F38 for ; Wed, 20 Jun 2018 15:25:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7C0AB28ED6; Wed, 20 Jun 2018 15:25:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2A17228EBF for ; Wed, 20 Jun 2018 15:25:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754097AbeFTPYp (ORCPT ); Wed, 20 Jun 2018 11:24:45 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:54507 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932341AbeFTPYk (ORCPT ); Wed, 20 Jun 2018 11:24:40 -0400 Received: by mail-wm0-f66.google.com with SMTP id o13-v6so183665wmf.4 for ; Wed, 20 Jun 2018 08:24:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=k+iZynWQRXvZ5615wlWaB9aY3Mmlz8ffNowSv6lWV9c=; b=Yi5PvRI/WvQZWuC7LBADIW/4S61zU6FsZnonsBPtHh1OnZr/tsw7/vgcilAYEPpp3P H7MOwSQfZAnX4kMMjr5GbcWRcrWLJUjgyo9MQQymOZwV6IhhzlVDJWd0fN0dkju/J6fP kuuowXeWkDK1Q1Zbw606Nm6H1UdvRSyROBOfOtpK/2ddCELHQLRsilicNU1P20TUmB+i ijMKrVL6HDf/W3bvGx1eijAeBX7IOub0BlEIuDAS2sPkjYisHX3IPc6514252u+k79/j 36kdUCz1UAbQ63TLoKQyKpwPU9dJP51RVzpkdc3SjxmH9ukUghNG1YH2/xltV/ZzVLLO uf7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=k+iZynWQRXvZ5615wlWaB9aY3Mmlz8ffNowSv6lWV9c=; b=Y6W4+e/TqgpLi7li1d8iDHGkvBrptaa4U3nmMkhYCm5DMQ6MW9PS9HWwUWg+9srRpV Ds3BGADT+cVzqpqEuV8YxOFclmOp58UiqjidopYNW1MrLF/rt9o4sb2iQPQChrSDY9DP hz1p5ucg33DTOXdWtJHAsLPvA7ja46dr++pOwgEIBLSB7AOC73jZP801guVXG/TT43Cr clzNgyGlryAUzfSnz+o4RGzZ+bfpP2MEDMTwl9X2ebyJ7QSw1g0fXiAWyt4Jg+pA307l JrjJoUIV3RU0/QHdv/jcO7frpBkZWAiSprDzpifAjYuHuJOHOEKcB49tAFa9BEx4+peD 8/dA== X-Gm-Message-State: APt69E0DUXDB/VDkGC+jZ6ErVsh1dRqNtL8ZIm0Bp7cqcoR0GfswvR3O ezEq+cY40gQeXYtcJIZs1r9AsA== X-Google-Smtp-Source: ADUXVKJXc6AKKDoJ+FdN8W93tAEIqcHbvpdSefvagKsbEhUe3hdApwEhSHA+uBzxdDaEIYJpEXocQA== X-Received: by 2002:a1c:3693:: with SMTP id y19-v6mr2024605wmh.71.1529508279217; Wed, 20 Jun 2018 08:24:39 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id c11-v6sm3959244wrm.65.2018.06.20.08.24.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jun 2018 08:24:38 -0700 (PDT) From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya Subject: [PATCH v4 6/7] arm64: update Documentation/arm64/tagged-pointers.txt Date: Wed, 20 Jun 2018 17:24:25 +0200 Message-Id: X-Mailer: git-send-email 2.18.0.rc1.244.gcf134e6275-goog In-Reply-To: References: Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a note that work on passing tagged user pointers to the kernel via syscalls has started, but might not be complete yet. Signed-off-by: Andrey Konovalov --- Documentation/arm64/tagged-pointers.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/arm64/tagged-pointers.txt b/Documentation/arm64/tagged-pointers.txt index a25a99e82bb1..361481283f00 100644 --- a/Documentation/arm64/tagged-pointers.txt +++ b/Documentation/arm64/tagged-pointers.txt @@ -35,8 +35,9 @@ Using non-zero address tags in any of these locations may result in an error code being returned, a (fatal) signal being raised, or other modes of failure. -For these reasons, passing non-zero address tags to the kernel via -system calls is forbidden, and using a non-zero address tag for sp is +Some initial work for supporting non-zero address tags passed to the +kernel via system calls has been done, but the kernel doesn't provide +any guarantees at this point. Using a non-zero address tag for sp is strongly discouraged. Programs maintaining a frame pointer and frame records that use non-zero