From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.6 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id D8B527DE74 for ; Wed, 18 Apr 2018 18:54:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753092AbeDRSxq (ORCPT ); Wed, 18 Apr 2018 14:53:46 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:43462 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753050AbeDRSxa (ORCPT ); Wed, 18 Apr 2018 14:53:30 -0400 Received: by mail-wr0-f193.google.com with SMTP id u4-v6so7512628wrg.10 for ; Wed, 18 Apr 2018 11:53:29 -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 :in-reply-to:references; bh=EZGWuFfiHqjCbpQnzR64TWy+WxEaujGKaSajXvCUFAc=; b=XoOfHGDK7SgM9AlCtWHh7oh0GHDm4VZCG+jh1df8Vj4ySECjuzY2zXvwQBEs+sLGqB 6riaTc1/uxe/qFc30n7Yu43YH+sX6eTZV9LRvLh4/hkMa9HIW1ugGQuFc/Ah0OBfOwD4 e4wTpiBLAFoOxv1VLZ3TY6TsbcUy/J2c5vEGhEcWec0e3bWZ1PAMsFqijpV7YERCLimq v9eHL8GFoVB/g8fTQkNuNPC8Av5ezgvUGKackOhu1rb3Z6JWUPuiUowbY9S4PRA7RR/d 5K5lAZD9nV60MKJlhgI6GNaaPOXgq20MGKk3ntFes0rUWxNS4SkHPFFi8EbDUB0/t6wD I2sw== 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:in-reply-to:references; bh=EZGWuFfiHqjCbpQnzR64TWy+WxEaujGKaSajXvCUFAc=; b=OqwPDOmUI0WxMQIhvUU1gkDfQMKxnibQFdueu0Ft8ptmXMKunyyN4r/QDwwc2cs15z dtPs53Kb9Pqa4lkqVxUUk4ks7R8FTzIlRF47u9MNJq1XmkVdw1R5twIN6cuUZ41DwIO1 1MF/bwsz2FYylbU6MiiWWW1dwzK9w7JMnY6bEwtU6ggm8C8DiM9i2br56GmziKepEzra //+EUjSuSxzCxtmo0gdkupN+/5iu7QT8dtofMwj2O0u/sJ59kqvGz4a2EtAljkVwNfFC fogp4Df1/YzLNJ73JEFfVZZDfjnk0H2EsF3xHTLI52kxiyPw/dXbYVxOpIGv7BGgwDT4 LZHg== X-Gm-Message-State: ALQs6tAzTGza79XK2dJyZi+ak2HSUC4ry9CikVtF13WMR1O1BGeUwANN GGdWwiSByfd7WH+hEom3VI0JRw== X-Google-Smtp-Source: AIpwx4+jqENAWip/MUW3PGvlX0PAg25j/IaqTVI58MpVYsnVtxnKfu+qYLlIBk/+1UQ8zcYiy7iy7A== X-Received: by 10.28.148.129 with SMTP id w123mr2649992wmd.116.1524077608370; Wed, 18 Apr 2018 11:53:28 -0700 (PDT) Received: from andreyknvl0.muc.corp.google.com ([2a00:79e0:15:10:84be:a42a:826d:c530]) by smtp.gmail.com with ESMTPSA id k79sm2616735wmg.39.2018.04.18.11.53.26 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Apr 2018 11:53:27 -0700 (PDT) From: Andrey Konovalov To: Catalin Marinas , Will Deacon , Jonathan Corbet , Mark Rutland , Robin Murphy , Al Viro , Andrey Konovalov , James Morse , Kees Cook , Bart Van Assche , Kate Stewart , Greg Kroah-Hartman , Thomas Gleixner , Philippe Ombredanne , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Dan Williams , "Aneesh Kumar K . V" , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan Subject: [PATCH 6/6] arm64: update Documentation/arm64/tagged-pointers.txt Date: Wed, 18 Apr 2018 20:53:15 +0200 Message-Id: <0fdb6332cc5bf333f80212d0b17edadd2bdc9fcf.1524077494.git.andreyknvl@google.com> X-Mailer: git-send-email 2.17.0.484.g0c8726318c-goog In-Reply-To: References: In-Reply-To: References: Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@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 -- 2.17.0.484.g0c8726318c-goog -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html