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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 848E3C433DF for ; Sun, 5 Jul 2020 19:42:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5BED42073E for ; Sun, 5 Jul 2020 19:42:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GEhJ6DMg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728006AbgGETmg (ORCPT ); Sun, 5 Jul 2020 15:42:36 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:25508 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727902AbgGETmg (ORCPT ); Sun, 5 Jul 2020 15:42:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593978155; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=Nre+vcTZuioR9qndvPPDHYxrgwQ/M91HckbWLUZ5+GI=; b=GEhJ6DMgET96C3B5LDrSaFxlRGouJP2lWaD+lNXEm6k4UADU+/7IKA/86f232D+6ejcNvW 1Z1DiVE6boUnQrBM1zJURodjhzFU1Skx0WtB0rGTEH5R1pi7N5DLC4Rjj70kLgjOwVKtRD IZQNbMq1Q6Clya4BsbepTO6Fov0uHQA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-389-C0tMnLRYPvyuwOP0ZQNRZA-1; Sun, 05 Jul 2020 15:42:33 -0400 X-MC-Unique: C0tMnLRYPvyuwOP0ZQNRZA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6BC321005510; Sun, 5 Jul 2020 19:42:31 +0000 (UTC) Received: from krava (unknown [10.40.192.42]) by smtp.corp.redhat.com (Postfix) with SMTP id D40AB7BD7F; Sun, 5 Jul 2020 19:42:25 +0000 (UTC) Date: Sun, 5 Jul 2020 21:42:25 +0200 From: Jiri Olsa To: linux-s390@vger.kernel.org, Sumanth Korikkar Cc: Alexei Starovoitov , Daniel Borkmann , Alexander Gordeev , Yauheni Kaliuta , netdev@vger.kernel.org, bpf@vger.kernel.org, Brendan Gregg , bas@baslab.org, Matheus Marchini , Daniel Xu Subject: bpf: bpf_probe_read helper restriction on s390x Message-ID: <20200705194225.GB3356590@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org hi, with following commit: 0ebeea8ca8a4 bpf: Restrict bpf_probe_read{, str}() only to archs where they work the bpf_probe_read BPF helper is restricted on architectures that have 'non overlapping address space' and select following config: select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE there's also nice explanation in this commit's changelog: 6ae08ae3dea2 bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers We have a problem with bpftrace not working properly on s390x because bpf_probe_read is no longer available, and bpftrace does not use bpf_probe_read_(user/kernel) variants yet. My question is if s390x is 'arch with overlapping address space' and we could fix this by adding ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE for s390x or we need to fix bpftrace to detect this, which we probably need to do in any case ;-) thanks, jirka