From patchwork Mon Aug 6 16:40:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 10557435 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 261F090E3 for ; Mon, 6 Aug 2018 16:41:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 15E652978E for ; Mon, 6 Aug 2018 16:41:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0960D29790; Mon, 6 Aug 2018 16:41:33 +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 8BA4C298D3 for ; Mon, 6 Aug 2018 16:41:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387833AbeHFSvC (ORCPT ); Mon, 6 Aug 2018 14:51:02 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:42953 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387798AbeHFSvB (ORCPT ); Mon, 6 Aug 2018 14:51:01 -0400 Received: by mail-wr1-f66.google.com with SMTP id e7-v6so12974024wrs.9 for ; Mon, 06 Aug 2018 09:41:07 -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=qyIb1LedubX4Bm4tOfTQFFJt+XM5l2v/UMtetdGR0wA=; b=SJkaC5hITo4nP+vXjYHN2mVUXmdrwLIHbNc8CpZmyoVvw3V7GtCN1wz4N7Al1vQJcF hd2hQ2Dda2FOZFaB3fi4YONbr7FkxJE0+zV6mYo8QkXkiP+cwOm4HdDWfXUKGfXTgQlN Q8wwiuZ3k//FGLrWLP4x7doPn4M/2AOprO2n9lsdrV3GL2iuZY36GdqROtoI4m5Lg5QZ FAAmEmPnQxfd5XtkyfuMIGdZRRZ9O3+CyxV3b1xZlSjyfDnCfuNe+F9+7eELSrWmRhH9 ogwsvNzG8jsKFD9+W2+dNbTKYfDwtsP7DnjDyEzq/aPqETSO9v2jfp/3lWSRQXXa9tjz rjcw== 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=qyIb1LedubX4Bm4tOfTQFFJt+XM5l2v/UMtetdGR0wA=; b=e3g/B2QJVNBBZBO0EBJxTQMWSqx/VLz+4prQHJ9uJbIkjM0CDficzFdZM55f5q3S69 2D6O9lSfI+m8+Pi3wYvfPCX47obYNYMN4d2nZ6gpSbxUVRv6udWl+kzKC2Gjdr7cB2Kr HJOqD779kIkj6gq7puchh/fTppy0TbP8o0NLoJ1QWgrwdKA1bP6CRSQrHOdgEMOjG6ZN XNhTalPL1jwC6oc09P0m0SsaxytRm5voBY96ExNDaH8rz7TTlFyY8rJJ6oKyOrvHOALW VyfwBc3Vn5zSEIogPmfBQLv0FFlQU3I91umRY9FQu9mrP/APaC/PspITTpAjnRCq1bG5 HCnQ== X-Gm-Message-State: AOUpUlEHURwmDSqcpeLnUO4MMssLIV7AyJmG+ozP38ctqg8M5yCskfHL cgGQFirJjh1V6xsG8usPdhZHng== X-Google-Smtp-Source: AAOMgpeO7k6j2TtDLWY/G7617DSwScmheLW9n+G6mjNCfjUdKJdVUj28MA6JiNxNbo41h0Nsk3UX4g== X-Received: by 2002:a5d:50cd:: with SMTP id f13-v6mr10733476wrt.73.1533573666455; Mon, 06 Aug 2018 09:41:06 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id 66-v6sm16385790wmw.34.2018.08.06.09.41.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Aug 2018 09:41:05 -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 v5 09/10] arm64: update Documentation/arm64/tagged-pointers.txt Date: Mon, 6 Aug 2018 18:40:44 +0200 Message-Id: <5396af31a51aaafd5d65742d1cc48854513be778.1533573460.git.andreyknvl@google.com> X-Mailer: git-send-email 2.18.0.597.ga71716f1ad-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