From patchwork Thu Aug 30 11:41:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10581525 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E7A2C139B for ; Thu, 30 Aug 2018 11:41:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D797A2BA60 for ; Thu, 30 Aug 2018 11:41:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CBB3D2BA68; Thu, 30 Aug 2018 11:41:37 +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=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL 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 7EB2E2BA60 for ; Thu, 30 Aug 2018 11:41:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728227AbeH3PnT (ORCPT ); Thu, 30 Aug 2018 11:43:19 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36321 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728651AbeH3PnS (ORCPT ); Thu, 30 Aug 2018 11:43:18 -0400 Received: by mail-wm0-f67.google.com with SMTP id j192-v6so1689531wmj.1 for ; Thu, 30 Aug 2018 04:41:35 -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 :mime-version:content-transfer-encoding; bh=W/jdbb2Vq3Kiym03/gav3BOUvcnL67E9+cfyfM7MhIU=; b=DMD4I/SS8lJ+d3U1+HP9Yl6kLLZHPhvAdJS/JxxXCHjmDxUF/UgLbg2LpoqOkcwLuR wQQPHq4FCtWNS5xr7a3yBgBLJiWBX59b39kyQUx1OqIRTZZTjyRpftdyJmGkxbABZFU6 5KDwphISdpfEXbTOa+4UH4EiTU/0Wi30p9H0GhSfdYr6ze+w3YzNJGGCjrGlYOzyxLmh iWSjewMZmvPQ1GwgRIhyGXsGTzAm8HlL91OxzULxqV+6QAR/5fdqnSyQQBmOZsTukWgi 9+fmCsSQzqxxTagM+2Wx2wT5yLGsY3A4DZXaZsUTAtgiarABDJqijOFj2slq5uuV7G9d s3yw== 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:mime-version:content-transfer-encoding; bh=W/jdbb2Vq3Kiym03/gav3BOUvcnL67E9+cfyfM7MhIU=; b=ieN/Jmwl/4Wjub1KDK3C1bnb3pQVDXs0cnLzusBhrESnCQcoTqN1uLUwT2s4PBV/ec 5/aQ9IpC89mAGlLly/G05I6JLuxgB68ipmycJlouo4wyZo8TSg39ptECJXcu+/iVo6qH ZfrU3g6O7GhPYRNxVAYQdYtK20FcZ+MVV3093fSImv+eM44+O5PNrKs1kybfkmPkE30p bOAiqwEJZd2/oyOaYnSF01gFx9Eyg6iEqKKDeCRNLBH+R0mVDWr0uuaFVpl9CmIAmcwt fx6t8I5jhEMxflTv8yk2QCo9VVJQJ2A/ZgxnK5nap/+JjkBFhpyWjTOUBC3M8vlw/izM OemQ== X-Gm-Message-State: APzg51C+9c3eGeecemcfi/4zRdRYjowdp14EU5igqpK4uY5CZdJgf8Pz VsFnsUqXyBOkwAu/mqQgphTBGA== X-Google-Smtp-Source: ANB0VdZJCY9SDGNv4X5vQQOPslJfwglBfynr1JnV8gKw4PAQtLtDlI07kC0OD66facMHWBf1VWf6KA== X-Received: by 2002:a1c:e54:: with SMTP id 81-v6mr1614151wmo.84.1535629293894; Thu, 30 Aug 2018 04:41:33 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id z184-v6sm2175218wmz.0.2018.08.30.04.41.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Aug 2018 04:41:33 -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 v6 09/11] arm64: update Documentation/arm64/tagged-pointers.txt Date: Thu, 30 Aug 2018 13:41:14 +0200 Message-Id: <594756b2aa9fea948f4da3cd01ffa8a5acbc5805.1535629099.git.andreyknvl@google.com> X-Mailer: git-send-email 2.19.0.rc0.228.g281dcd1b4d0-goog In-Reply-To: References: MIME-Version: 1.0 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