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=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_MED,USER_IN_DEF_DKIM_WL autolearn=ham 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 281ADC1B0F6 for ; Wed, 20 Jun 2018 15:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4AD2208B7 for ; Wed, 20 Jun 2018 15:24:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Yi5PvRI/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4AD2208B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932434AbeFTPYr (ORCPT ); Wed, 20 Jun 2018 11:24:47 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:51523 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932308AbeFTPYk (ORCPT ); Wed, 20 Jun 2018 11:24:40 -0400 Received: by mail-wm0-f67.google.com with SMTP id r15-v6so221206wmc.1 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=jXVUg6QJJV+MOeuH6qxOkdCsrHmQihYKLufq2S7G7gTTCnf30Iv4XUyM0bMazKksZ0 VlrzFPqE6gfWjEDCOWC/0Ium0Z+NKLGl/rjBacuXSOWIzpqMIHiScUI5AUNGAmoyuKN0 qtqHelufqmulyo3Bo6VSlBtVOFjYQbYbxfMhO82m9T6+PtISpfa5p7f60BIKtxy5jD7i oU/lvju06lYp6aRUvY1ScyCbr/mFX4ryx2FZYP+UTcKY1u2AwpIpCJSgtbk5iwDw4AV5 xaihZuXsghUOkBaIT7QiZFBT9st74nnCN4jfgac86aLHAqxkizJVDUjWXX8Z4ch2XE+k 7vHQ== X-Gm-Message-State: APt69E0DUXsCFpIVR/zy6WDDt/i873ERi94ZzSc87uh1L/dS8fVC0Kh8 lbMzeaTeSUDr39lG5qpxfPeDhw== 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 -- 2.18.0.rc1.244.gcf134e6275-goog