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 X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8B13C388F9 for ; Fri, 23 Oct 2020 06:30:38 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7868020829 for ; Fri, 23 Oct 2020 06:30:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7868020829 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4CHZ9P6RcZzDr3f for ; Fri, 23 Oct 2020 17:30:33 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4CHZ7v1jgczDqxQ for ; Fri, 23 Oct 2020 17:29:15 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4CHZ7t42F5z8t65 for ; Fri, 23 Oct 2020 17:29:14 +1100 (AEDT) Received: by ozlabs.org (Postfix) id 4CHZ7t3g5Vz9sTc; Fri, 23 Oct 2020 17:29:14 +1100 (AEDT) Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=csgroup.eu Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4CHZ7s1TBgz9sTK for ; Fri, 23 Oct 2020 17:29:04 +1100 (AEDT) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4CHZ7Z1XvLz9txKQ; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 5xU1EsiLkadC; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4CHZ7Z0XBsz9txKP; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id E8A988B854; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id kEEewvCugbio; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 7BB828B773; Fri, 23 Oct 2020 08:28:58 +0200 (CEST) Subject: Re: C vdso From: Christophe Leroy To: Michael Ellerman References: <20200916165516.Horde.uocmo3irPb7BMg__NUSqRA9@messagerie.si.c-s.fr> <87r1r0oa4o.fsf@mpe.ellerman.id.au> Message-ID: Date: Fri, 23 Oct 2020 08:28:55 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linuxppc-dev@ozlabs.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Michael, Le 24/09/2020 à 15:17, Christophe Leroy a écrit : > Hi Michael > > Le 17/09/2020 à 14:33, Michael Ellerman a écrit : >> Hi Christophe, >> >> Christophe Leroy writes: >>> Hi Michael, >>> >>> What is the status with the generic C vdso merge ? >>> In some mail, you mentionned having difficulties getting it working on >>> ppc64, any progress ? What's the problem ? Can I help ? >> >> Yeah sorry I was hoping to get time to work on it but haven't been able >> to. >> >> It's causing crashes on ppc64 ie. big endian. >> > >> >> As you can see from the instruction dump we have jumped into the weeds somewhere. >> >> We also had the report from the kbuild robot about rela.opd being >> discarded, which I think is indicative of a bigger problem. ie. we don't >> process relocations for the VDSO, but opds require relocations (they >> contain an absolute pointer). >> >> I thought we could get away with that, because the VDSO entry points >> aren't proper functions (so they don't have opds), and I didn't think >> we'd be calling via function pointers in the VDSO code (which would >> require opds). But seems something is not working right. >> >> Sorry I haven't got back to you with those details. Things are a bit of >> a mess inside IBM at the moment (always?), and I've been trying to get >> everything done before I take a holiday next week. >> > > > Can you tell what defconfig you are using ? I have been able to setup a full glibc PPC64 cross > compilation chain and been able to test it under QEMU with success, using Nathan's vdsotest tool. What config are you using ? Christophe > > I tested with both ppc64_defconfig and pseries_defconfig. > > The only problem I got is with getcpu, which segfaults but both before and after applying my series, > so I guess this is unrelated. > > Not sure we can pay too much attention to the exact measurement as it is a ppc64 QEMU running on a > x86 Linux which is running in a Virtual Box on a x86 windows Laptop, but at least it works: > > Without the series: > > clock-getres-monotonic: vdso: 389 nsec/call > clock-gettime-monotonic: vdso: 781 nsec/call > clock-getres-monotonic-coarse: vdso: 13715 nsec/call > clock-gettime-monotonic-coarse: vdso: 312 nsec/call > clock-getres-monotonic-raw: vdso: 13589 nsec/call > clock-getres-tai: vdso: 13827 nsec/call > clock-gettime-tai: vdso: 14846 nsec/call > clock-getres-boottime: vdso: 13596 nsec/call > clock-gettime-boottime: vdso: 14758 nsec/call > clock-getres-realtime: vdso: 327 nsec/call > clock-gettime-realtime: vdso: 717 nsec/call > clock-getres-realtime-coarse: vdso: 14102 nsec/call > clock-gettime-realtime-coarse: vdso: 299 nsec/call > gettimeofday: vdso: 771 nsec/call > > With the series: > > clock-getres-monotonic: vdso: 350 nsec/call > clock-gettime-monotonic: vdso: 726 nsec/call > clock-getres-monotonic-coarse: vdso: 356 nsec/call > clock-gettime-monotonic-coarse: vdso: 423 nsec/call > clock-getres-monotonic-raw: vdso: 349 nsec/call > clock-getres-tai: vdso: 419 nsec/call > clock-gettime-tai: vdso: 724 nsec/call > clock-getres-boottime: vdso: 352 nsec/call > clock-gettime-boottime: vdso: 752 nsec/call > clock-getres-realtime: vdso: 351 nsec/call > clock-gettime-realtime: vdso: 733 nsec/call > clock-getres-realtime-coarse: vdso: 356 nsec/call > clock-gettime-realtime-coarse: vdso: 367 nsec/call > gettimeofday: vdso: 796 nsec/call > > > Thanks > Christophe