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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 36EC2C5B576 for ; Sun, 30 Jun 2019 04:42:38 +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 B6535206A2 for ; Sun, 30 Jun 2019 04:42:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6535206A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45byXq4Bk8zDqpy for ; Sun, 30 Jun 2019 14:42:35 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=anshuman.khandual@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 45byVr1mYdzDqp7 for ; Sun, 30 Jun 2019 14:40:50 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5A8E728; Sat, 29 Jun 2019 21:40:47 -0700 (PDT) Received: from [192.168.0.129] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5ECD73F706; Sat, 29 Jun 2019 21:40:37 -0700 (PDT) From: Anshuman Khandual Subject: Re: [PATCH] mm: Generalize and rename notify_page_fault() as kprobe_page_fault() To: Guenter Roeck References: <1560420444-25737-1-git-send-email-anshuman.khandual@arm.com> <20190629145009.GA28613@roeck-us.net> Message-ID: <78863cd0-8cb5-c4fd-ed06-b1136bdbb6ef@arm.com> Date: Sun, 30 Jun 2019 10:11:03 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190629145009.GA28613@roeck-us.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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: Mark Rutland , Michal Hocko , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , James Hogan , Dave Hansen , Will Deacon , linux-mips@vger.kernel.org, linux-mm@kvack.org, Paul Mackerras , sparclinux@vger.kernel.org, Stephen Rothwell , Yoshinori Sato , x86@kernel.org, Russell King , Matthew Wilcox , Ingo Molnar , Catalin Marinas , linux-snps-arc@lists.infradead.org, Fenghua Yu , linux-s390@vger.kernel.org, Andrey Konovalov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Tony Luck , Heiko Carstens , Vineet Gupta , linux-kernel@vger.kernel.org, Ralf Baechle , Paul Burton , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hello Guenter, On 06/29/2019 08:20 PM, Guenter Roeck wrote: > Hi, > > On Thu, Jun 13, 2019 at 03:37:24PM +0530, Anshuman Khandual wrote: >> Architectures which support kprobes have very similar boilerplate around >> calling kprobe_fault_handler(). Use a helper function in kprobes.h to unify >> them, based on the x86 code. >> >> This changes the behaviour for other architectures when preemption is >> enabled. Previously, they would have disabled preemption while calling the >> kprobe handler. However, preemption would be disabled if this fault was >> due to a kprobe, so we know the fault was not due to a kprobe handler and >> can simply return failure. >> >> This behaviour was introduced in the commit a980c0ef9f6d ("x86/kprobes: >> Refactor kprobes_fault() like kprobe_exceptions_notify()") >> > > With this patch applied, parisc:allmodconfig images no longer build. > > In file included from arch/parisc/mm/fixmap.c:8: > include/linux/kprobes.h: In function 'kprobe_page_fault': > include/linux/kprobes.h:477:9: error: > implicit declaration of function 'kprobe_fault_handler'; did you mean 'kprobe_page_fault'? Yikes.. Arch parisc does not even define (unlike mips which did but never exported) now required function kprobe_fault_handler() when CONFIG_KPROBES is enabled. I believe rather than defining one stub version only for parsic it would be better to have an weak symbol generic stub definition for kprobe_fault_handler() in file include/linux/kprobes.h when CONFIG_KPROBES is enabled along side the other stub definition when !CONFIG_KPROBES. But arch which wants to use kprobe_page_fault() cannot use stub kprobe_fault_handler() definition and will have to provide one. I will probably add a comment regarding this. > > Reverting the patch fixes the problem. > > Guenter > Thanks for reporting the problem.