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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 976F1C46475 for ; Thu, 25 Oct 2018 17:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34A5720834 for ; Thu, 25 Oct 2018 17:33:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="EWLiBnB+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 34A5720834 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727662AbeJZCGr (ORCPT ); Thu, 25 Oct 2018 22:06:47 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:34646 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727455AbeJZCGr (ORCPT ); Thu, 25 Oct 2018 22:06:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=S3YoGq4XbxQXDh2VwC+Lw5UGYV5iCRqWdlrOL2/2RjM=; b=EWLiBnB+VM/z0Cfx5aOPvks8h gkWXS8vKFkt1JcORp2XOzwtDecCJ3uZsKFkum4WBtO1VlKposOJTjNAQ6Pcrnfpe0Bz7opRd43vPg tuTY7Wz0BkpsdL2WJFcyFmc3Pu5oOvvJUQLFuYlJzRSg7sWa8a1xY1fyAZ6+GQ0Rzdsc0=; Received: from n2100.armlinux.org.uk ([2002:4e20:1eda:1:214:fdff:fe10:4f86]:54692) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.90_1) (envelope-from ) id 1gFjV0-0000NI-5R; Thu, 25 Oct 2018 18:32:46 +0100 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.90_1) (envelope-from ) id 1gFjUx-000132-KO; Thu, 25 Oct 2018 18:32:43 +0100 Date: Thu, 25 Oct 2018 18:32:42 +0100 From: Russell King - ARM Linux To: Florian Fainelli Cc: Andrew Lunn , linux-arm-kernel@lists.infradead.org, Ravi Bangoria , Peter Zijlstra , Kim Phillips , Thomas Richter , open list , Arnaldo Carvalho de Melo , Alexander Shishkin , Ingo Molnar , Greg Kroah-Hartman , Namhyung Kim , Thomas Gleixner , Jiri Olsa , l.stach@pengutronix.de Subject: Re: [PATCH 2/2] perf tests: Add a test for the ARM 32-bit [vectors] page Message-ID: <20181025173242.GC30658@n2100.armlinux.org.uk> References: <20181025000905.6095-1-f.fainelli@gmail.com> <20181025000905.6095-3-f.fainelli@gmail.com> <20181025021013.GA30116@lunn.ch> <175fd725-a97a-c282-5aa1-952014ff9023@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <175fd725-a97a-c282-5aa1-952014ff9023@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 25, 2018 at 10:19:54AM -0700, Florian Fainelli wrote: > On 10/24/18 7:10 PM, Andrew Lunn wrote: > > On Wed, Oct 24, 2018 at 05:09:05PM -0700, Florian Fainelli wrote: > >> perf on ARM requires CONFIG_KUSER_HELPERS to be turned on to allow some > >> independance with respect to the ARM CPU being used. Add a test which > >> tries to locate the [vectors] page, created when CONFIG_KUSER_HELPERS is > >> turned on to help asses the system's health. > > > > Hi Florian > > > > I've suffered the pain from missing CONFIG_KUSER_HELPERS. The > > segfaults give little clue as to what is going wrong,and gdb is not > > much use either. > > If you have a working backtrace, you can typically see the virtual > address being in 0xffff_xxxx which gives a bit of a clue, but yes, this > is not particularly helpful. > > > > > What i don't see here is any clue to CONFIG_KUSER_HELPERS. If the test > > fails, could you print a message suggesting CONFIG_KUSER_HELPERS on > > ARM? > > Sure, sounds reasonable, thanks for taking a look. An alternative would be rather than adding this to user programs, to have the kernel detect it and print a warning itself. BTW, I note that the help text for CONFIG_KUSER_HELPERS needs to be updated. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up