From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-1.mimecast.com (us-smtp-2.mimecast.com [207.211.31.81]) by sourceware.org (Postfix) with ESMTP id 3B88D3857C42 for ; Fri, 24 Jul 2020 08:06:52 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 3B88D3857C42 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-437-cyi8d98zOgqOWzeAWGvS7g-1; Fri, 24 Jul 2020 04:06:49 -0400 X-MC-Unique: cyi8d98zOgqOWzeAWGvS7g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8F33A106B244; Fri, 24 Jul 2020 08:06:48 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-112-154.ams2.redhat.com [10.36.112.154]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5ECB910013C0; Fri, 24 Jul 2020 08:06:44 +0000 (UTC) From: Florian Weimer To: Szabolcs Nagy Cc: jeremy.linton@arm.com, Jakub Jelinek , Jeff Law , Carlos O'Donell , libc-alpha@sourceware.org Subject: Re: [PATCH v7 14/14] aarch64: add NEWS entry about branch protection support References: <90d6dfb05675c96e1f4cd35187d2fb783fc00204.1594209990.git.szabolcs.nagy@arm.com> <87a6zpbcry.fsf@oldenburg2.str.redhat.com> <20200724075018.GK7127@arm.com> Date: Fri, 24 Jul 2020 10:06:42 +0200 In-Reply-To: <20200724075018.GK7127@arm.com> (Szabolcs Nagy's message of "Fri, 24 Jul 2020 08:50:18 +0100") Message-ID: <87v9id9w19.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-7.2 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jul 2020 08:06:53 -0000 * Szabolcs Nagy: > i require --enable-standard-branch-protection exactly > because gcc target libs and crt files are not branch > protected by default, this can change later (always > build target libs with branch protection), but i > consider it risky given that the pac-ret instructions > can be mishandled by custom unwinders who don't know > the new dwarf op code for it or tools that don't > understand the gnu property notes (note handling in > binutils can be checked at gcc build time, but other > things cannot be, so there will be some risk when using > a gcc with branch-protection and it will take some time > to find the issues given the lack of hardware) Okay, then the NEWS entry is appriate, and we did not follow the required steps for enabling this feature in Fedora 33. 8-( Thanks, Florian