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: 10477767 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 0CF6B60230 for ; Wed, 20 Jun 2018 15:28:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 588552863C for ; Wed, 20 Jun 2018 15:28:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4D10328653; Wed, 20 Jun 2018 15:28:36 +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=-2.9 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, DKIM_VALID, MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id BCCBC2863C for ; Wed, 20 Jun 2018 15:28:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=RL3Yyt+9uLWbeqHmyio9YKPpzmj388KP+bPTAk9w4AY=; b=H5n0g1Pc441YDwWtpCYCc364Fx 9fXYXTuLYNZbcCmziYZH6h+87809L/Szcq7QojUKYpJRODvHla+2mHAQTElJ3k8CInUtdrdsm12ts U99VoUzAsl0ASWvXnHC0kUGE+ncCWRtByxSKfiKW7dgEx9cuPFXQU2V2LRsWoV5sASTALWOTcMFxv 952wuXEYz9d6eJu8T2tu5MdNYsXCBeiihZ3uaqR8cGKcPnWJuzP9BL0VTUKI6pRf3Ws5DG++QRGb0 qpV0GgI6ijS6QdWgkxiJWaJD1Q4TeyeipS8vzhiHCbNyv7n+mhdOBYUZaE5UtwOfyb3wXD9PgZxZo zrzo7qkQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fVf22-0008MI-CW; Wed, 20 Jun 2018 15:28:26 +0000 Received: from mail-wm0-x242.google.com ([2a00:1450:400c:c09::242]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fVeyX-00059e-EY for linux-arm-kernel@lists.infradead.org; Wed, 20 Jun 2018 15:24:51 +0000 Received: by mail-wm0-x242.google.com with SMTP id p11-v6so203918wmc.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=X+qI40fgtd0bOAPqGlPC0CEivaQQNd8MFOgs5axuLtgqTfJY3TeeeQQTr1iajIyLfj y6c43ZS6MrWT1jpEQuzKkiEjaHWXDYwZHaqBzUY+ME3EzOzFISPhdAu664xme/+7yz8F 6y5g4kQBgqJZ8rW+gKkjaSv4VutZ8DAxFzJepYozl6cGx4h/HDdhJncz2F3wFSB9rWlS FBaXV3CSom10MqW6raHY+F+8dGIz0w4zn4rkk6aKs9qZmTopC7+Gf6CGNfKlLCIelTkW 4eNOws5lzT57C3RSIRnyUSStlyHxgHK37Ry8ix4AZVkV9M2mNg3t+HZEo4sR8rXAW6di yXXQ== X-Gm-Message-State: APt69E0ve8Szrdq6o2QKri7wmJlA3zSELk+7vWFzcR3k6ajC2e2JGI1Q vmkPyGKeQTMwd2QS/+Z8TfwB7A== 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 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: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180620_082449_514280_42A9A871 X-CRM114-Status: GOOD ( 14.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chintan Pandya , Jacob Bramley , Ruben Ayrapetyan , Lee Smith , Kostya Serebryany , Dmitry Vyukov , Ramana Radhakrishnan , Evgeniy Stepanov MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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