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 361E9C25B06 for ; Wed, 10 Aug 2022 12:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231916AbiHJMNw (ORCPT ); Wed, 10 Aug 2022 08:13:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229476AbiHJMNu (ORCPT ); Wed, 10 Aug 2022 08:13:50 -0400 Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAC1E6AA08; Wed, 10 Aug 2022 05:13:48 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id B914F43E374; Wed, 10 Aug 2022 08:13:47 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 8t9Hz8TKmCkp; Wed, 10 Aug 2022 08:13:47 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 299A343E476; Wed, 10 Aug 2022 08:13:47 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 299A343E476 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1660133627; bh=0eurnLuzGZ3qRL2RZDsSm+WisnojruHn4tv9O7FmRX8=; h=Date:From:To:Message-ID:MIME-Version; b=QQxEv68RxQrIJUHel8B5NqVQiSRYnTSX4SMexm5Stu1Q6lDuB3Ld3kNF2nGXeiFaz 0IKoFvLzBOXNgbT2unYVeCTDOIH8xQ0HOrNsOldtTX8qr4iF1NDl5/DKOD8/v4HMR6 PMivxdTdid9OgK3LPHZRDRAgQ6N2N8CoRdQKvT3w2ir1Z+XqJVN6Xk/Vov3cnRjxLc hShyheT/68e7en/rTTa1gcsdqJPqxrUFbFOT1k3NwvCvbbnIXz+kBNi5fQe2/+okH8 MSKifwpchrzhRFkCX6bsVwD8NNb/dq3SzM4HXydzMHSr+yZb10QsTDgSme9/sFNQHO +kKVcxxeW2KEA== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id mEyeHWUF-4Si; Wed, 10 Aug 2022 08:13:47 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 10D1543E88F; Wed, 10 Aug 2022 08:13:47 -0400 (EDT) Date: Wed, 10 Aug 2022 08:13:46 -0400 (EDT) From: Mathieu Desnoyers To: Sean Christopherson Cc: Gavin Shan , shuah , Florian Weimer , kvmarm , KVM list , linux-kselftest , linux-kernel , Paolo Bonzini , maz , oliver upton , andrew jones , yihyu , shan gavin Message-ID: <1478461718.353.1660133626967.JavaMail.zimbra@efficios.com> In-Reply-To: References: <20220809060627.115847-1-gshan@redhat.com> <8735e6ncxw.fsf@oldenburg.str.redhat.com> <7844e3fa-e49e-de75-e424-e82d3a023dd6@redhat.com> <87o7wtnay6.fsf@oldenburg.str.redhat.com> <616d4de6-81f6-9d14-4e57-4a79fec45690@redhat.com> <797306043.114963.1660047714774.JavaMail.zimbra@efficios.com> <1014177394.115022.1660052656961.JavaMail.zimbra@efficios.com> Subject: Re: [PATCH 1/2] KVM: selftests: Make rseq compatible with glibc-2.35 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_4372 (ZimbraWebClient - FF103 (Linux)/8.8.15_GA_4372) Thread-Topic: selftests: Make rseq compatible with glibc-2.35 Thread-Index: 2L3u2zUliaiWmqLcWHUzldusZle8bA== Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org ----- On Aug 9, 2022, at 5:38 PM, Sean Christopherson seanjc@google.com wrote: > On Tue, Aug 09, 2022, Mathieu Desnoyers wrote: >> ----- On Aug 9, 2022, at 8:21 AM, Mathieu Desnoyers >> mathieu.desnoyers@efficios.com wrote: >> >> > ----- Gavin Shan wrote: >> >> Hi Florian, >> >> >> >> On 8/9/22 5:16 PM, Florian Weimer wrote: >> >> >>> __builtin_thread_pointer doesn't work on all architectures/GCC >> >> >>> versions. >> >> >>> Is this a problem for selftests? >> >> >>> >> >> >> >> >> >> It's a problem as the test case is running on all architectures. I think I >> >> >> need introduce our own __builtin_thread_pointer() for where it's not >> >> >> supported: (1) PowerPC (2) x86 without GCC 11 >> >> >> >> >> >> Please let me know if I still have missed cases where >> >> >> __buitin_thread_pointer() isn't supported? >> >> > >> >> > As far as I know, these are the two outliers that also have rseq >> >> > support. The list is a bit longer if we also consider non-rseq >> >> > architectures (csky, hppa, ia64, m68k, microblaze, sparc, don't know >> >> > about the Linux architectures without glibc support). >> >> > >> >> >> >> For kvm/selftests, there are 3 architectures involved actually. So we >> >> just need consider 4 cases: aarch64, x86, s390 and other. For other >> >> case, we just use __builtin_thread_pointer() to maintain code's >> >> integrity, but it's not called at all. >> >> >> >> I think kvm/selftest is always relying on glibc if I'm correct. >> > >> > All those are handled in the rseq selftests and in librseq. Why duplicate all >> > that logic again? >> >> More to the point, considering that we have all the relevant rseq registration >> code in tools/testing/selftests/rseq/rseq.c already, and the relevant thread >> pointer getter code in tools/testing/selftests/rseq/rseq-*thread-pointer.h, >> is there an easy way to get test applications in tools/testing/selftests/kvm >> and in tools/testing/selftests/rseq to share that common code ? >> >> Keeping duplicated compatibility code is bad for long-term maintainability. > > Any reason not to simply add tools/lib/rseq.c and then expose a helper to get > the > registered rseq struct? Indeed, moving rseq.c to tools/lib/ would allow building a .so from any selftest which needs to use it. And we could move the relevant rseq helper header files to tools/include/rseq/* as well. Thoughts ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com