From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by inbox.vuxu.org (Postfix) with SMTP id 9FFBB283E6 for ; Wed, 14 Feb 2024 15:03:18 +0100 (CET) Received: (qmail 13314 invoked by uid 550); 14 Feb 2024 14:00:14 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 12255 invoked from network); 14 Feb 2024 14:00:13 -0000 Date: Wed, 14 Feb 2024 09:03:21 -0500 From: Rich Felker To: Thorsten Glaser Cc: musl@lists.openwall.com Message-ID: <20240214140321.GD4163@brightrain.aerifal.cx> References: <20240212224657.GA4163@brightrain.aerifal.cx> <20240213020834.GB4163@brightrain.aerifal.cx> <20240214021925.GC4163@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] PAC/BTI Support on aarch64 On Wed, Feb 14, 2024 at 01:32:13PM +0000, Thorsten Glaser wrote: > Markus Wichmann dixit: > > >According to Intel, the ENDBR64 instruction decodes as NOP on older > >processors. > > That’s unfortunately only true for processors manufactored by Intel. > There exist 686-class CPUs that don’t handle these and other long nops > so it’s best omitted on generic, as in not -march=native, builds. Lovely. So yet another reason the Intel thing sounds unusable in practice while the ARM thing seems very reasonable to support... Since you mentioned 686-class which are 32-bit, is the same true for x86_64, or is the situation better there? Rich