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=-4.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 E672BC433E6 for ; Fri, 28 Aug 2020 06:24:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AB06620757 for ; Fri, 28 Aug 2020 06:24:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aM1pukEv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AB06620757 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 40B6F6B0002; Fri, 28 Aug 2020 02:24:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 395BA6B0003; Fri, 28 Aug 2020 02:24:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 25D5D8E0003; Fri, 28 Aug 2020 02:24:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0072.hostedemail.com [216.40.44.72]) by kanga.kvack.org (Postfix) with ESMTP id 0AAAA6B0002 for ; Fri, 28 Aug 2020 02:24:19 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id B7ABC180AD817 for ; Fri, 28 Aug 2020 06:24:18 +0000 (UTC) X-FDA: 77198987796.22.pet00_630991927073 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id 59E8518038E67 for ; Fri, 28 Aug 2020 06:24:18 +0000 (UTC) X-HE-Tag: pet00_630991927073 X-Filterd-Recvd-Size: 3960 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 28 Aug 2020 06:24:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598595857; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TZgOlmN9m49e++aSj4JPimMgy9NjdrTL35m0T++hZyQ=; b=aM1pukEv+frLqm1sbyFKzeg1EoWbysRX8S/zmBAWwJk66sGw/kBgFd5oc8lKQWCMNBgYfC lKRRMdrLR+/e2IH33VRqKiJk/mQP9SwcBVq/HSYyKzifAg71m3WSY60+71wR5EXmdHRnwU ncWWn1k5/RxU4+sgqXd6DzOL5ayINro= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-443-M3H7_1grNueY-FhKFkSSmQ-1; Fri, 28 Aug 2020 02:24:12 -0400 X-MC-Unique: M3H7_1grNueY-FhKFkSSmQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 501DC1DDFF; Fri, 28 Aug 2020 06:24:08 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-112-37.ams2.redhat.com [10.36.112.37]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4A6655D9F1; Fri, 28 Aug 2020 06:23:55 +0000 (UTC) From: Florian Weimer To: "H.J. Lu" Cc: Andy Lutomirski , "Yu\, Yu-cheng" , Dave Martin , Dave Hansen , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , LKML , "open list\:DOCUMENTATION" , Linux-MM , linux-arch , Linux API , Arnd Bergmann , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Weijiang Yang Subject: Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack References: <4BDFD364-798C-4537-A88E-F94F101F524B@amacapital.net> Date: Fri, 28 Aug 2020 08:23:54 +0200 In-Reply-To: (H. J. Lu's message of "Thu, 27 Aug 2020 18:44:27 -0700") Message-ID: <87v9h3thj9.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Rspamd-Queue-Id: 59E8518038E67 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * H. J. Lu: > Can you think of ANY issues of passing more arguments to arch_prctl? On x32, the glibc arch_prctl system call wrapper only passes two arguments to the kernel, and applications have no way of detecting that. musl only passes two arguments on all architectures. It happens to work anyway with default compiler flags, but that's an accident. Thanks, Florian