From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 226947D2F0 for ; Wed, 14 Aug 2019 16:07:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728273AbfHNQG7 (ORCPT ); Wed, 14 Aug 2019 12:06:59 -0400 Received: from mga17.intel.com ([192.55.52.151]:38992 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726047AbfHNQG7 (ORCPT ); Wed, 14 Aug 2019 12:06:59 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Aug 2019 09:06:58 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,385,1559545200"; d="scan'208";a="184358026" Received: from yyu32-desk1.sc.intel.com ([10.144.153.205]) by FMSMGA003.fm.intel.com with ESMTP; 14 Aug 2019 09:06:58 -0700 Message-ID: <84fc1b3bb2dbcf52ca79cb1141a431e087f082b5.camel@intel.com> Subject: Re: [PATCH v8 01/27] Documentation/x86: Add CET description From: Yu-cheng Yu To: Florian Weimer Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin Date: Wed, 14 Aug 2019 08:57:19 -0700 In-Reply-To: <87tvakgofi.fsf@oldenburg2.str.redhat.com> References: <20190813205225.12032-1-yu-cheng.yu@intel.com> <20190813205225.12032-2-yu-cheng.yu@intel.com> <87tvakgofi.fsf@oldenburg2.str.redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.1-2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, 2019-08-14 at 10:07 +0200, Florian Weimer wrote: > * Yu-cheng Yu: > > > +ENDBR > > + The compiler inserts an ENDBR at all valid branch targets. Any > > + CALL/JMP to a target without an ENDBR triggers a control > > + protection fault. > > Is this really correct? I think ENDBR is needed only for indirect > branch targets where the jump/call does not have a NOTRACK prefix. You are right. I will fix the wording. Yu-cheng