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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1C6EC28D13 for ; Thu, 25 Aug 2022 13:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242311AbiHYNMy convert rfc822-to-8bit (ORCPT ); Thu, 25 Aug 2022 09:12:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242339AbiHYNMx (ORCPT ); Thu, 25 Aug 2022 09:12:53 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AB84AF4B5 for ; Thu, 25 Aug 2022 06:12:47 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-55-HXv8MwvfNtijA9b15ilGWA-1; Thu, 25 Aug 2022 14:12:44 +0100 X-MC-Unique: HXv8MwvfNtijA9b15ilGWA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.38; Thu, 25 Aug 2022 14:12:42 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.040; Thu, 25 Aug 2022 14:12:42 +0100 From: David Laight To: 'Peter Zijlstra' , Segher Boessenkool CC: Borislav Petkov , X86 ML , Michael Matz , "linux-toolchains@vger.kernel.org" , LKML , "Josh Poimboeuf" Subject: RE: [PATCH] x86/sev: Mark snp_abort() noreturn Thread-Topic: [PATCH] x86/sev: Mark snp_abort() noreturn Thread-Index: AQHYuE2/3wA7Q5vXrk6DdQVA60XyvK2/lqOw Date: Thu, 25 Aug 2022 13:12:42 +0000 Message-ID: References: <20220824152420.20547-1-bp@alien8.de> <20220824172929.GA25951@gate.crashing.org> <20220824224144.GC25951@gate.crashing.org> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org ... > Objtool follows control flow. As you said above, noreturn functions > behave differently and code-gen after a call to a noreturn function > stops. Thinks.... How near is objtool to outputting a list of functions and the stack offset at which they call something else? With the 'magic numbers' to track indirect jumps that is very nearly enough information to do full static stack depth checking. Recursive calls are a problem - but they ought to be banned in kernel anyway. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)