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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=unavailable 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 13BACC282DC for ; Wed, 17 Apr 2019 10:03:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFAB620835 for ; Wed, 17 Apr 2019 10:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731633AbfDQKD4 (ORCPT ); Wed, 17 Apr 2019 06:03:56 -0400 Received: from foss.arm.com ([217.140.101.70]:42266 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726237AbfDQKD4 (ORCPT ); Wed, 17 Apr 2019 06:03:56 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 13106374; Wed, 17 Apr 2019 03:03:56 -0700 (PDT) Received: from mbp (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 23D433F68F; Wed, 17 Apr 2019 03:03:53 -0700 (PDT) Date: Wed, 17 Apr 2019 11:03:51 +0100 From: Catalin Marinas To: Russell King - ARM Linux admin Cc: Christoph Hellwig , Heinrich Schuchardt , stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann Subject: Re: [PATCH 1/1] arm: mm: Export __sync_icache_dcache() for xen-privcmd Message-ID: <20190417100351.oix3df7hwwivgf7k@mbp> References: <20190413163052.11407-1-xypron.glpk@gmx.de> <20190415055109.GB9279@infradead.org> <20190417094137.2gkbtinldiwbkvwy@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190417094137.2gkbtinldiwbkvwy@shell.armlinux.org.uk> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 17, 2019 at 10:41:37AM +0100, Russell King wrote: > On Sun, Apr 14, 2019 at 10:51:09PM -0700, Christoph Hellwig wrote: > > On Sat, Apr 13, 2019 at 06:30:52PM +0200, Heinrich Schuchardt wrote: > > > This patch avoids > > > ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined! > > > observed when compiling v4.19.34. > > > > > > The xen-privcmd driver, which can be modular, calls set_pte_at() > > > which in turn may call __sync_icache_dcache(). > > > > Maybe that really is a sign that it should not be modular.. > > This issue has been discussed several times, and this URL gives a list > of all messages on linux-arm-kernel that mention __sync_icache_dcache: > > https://archive.armlinux.org.uk/lurker/search/20380101.000000.00000000@ml:linux-arm-kernel,sb:__sync_icache_dcache.en.html > > At the beginning of March, Boris Ostrovsky pointed that another solution > is available that does not need architecture private symbols to be > exported. > > Since I've already said in a previous thread that I don't want this > function exported, it seems the way forward is pretty obvious. Arnd submitted a patch, not sure what happened to it: https://lore.kernel.org/lkml/20190304204826.2414365-1-arnd@arndb.de/ I think this boils down to whether set_pte_at() is allowed to be called from loadable modules. If yes, __sync_icache_dcache() needs exporting, otherwise Arnd's patch makes the relevant code built-in (and, if merged, I'm happy to revert the similar export on arm64). -- Catalin 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=-3.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 C2764C10F12 for ; Wed, 17 Apr 2019 10:04:07 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 91473206BA for ; Wed, 17 Apr 2019 10:04:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JUhdWjCY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91473206BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WuEV73qtwnhpBMtyObccdYlQi9uZ8dBh6gsPwZUNt0M=; b=JUhdWjCYmR0eD5 WOgKx7fe96xPON2491zba1Q1I2VNCabkGwIoNbdEqkpMIlfd0caXWw6EPsbuMiDnKSYdhoFISqs3R /w4+7eIA9AiEqg7CS2Q0gVcGlSIxowcllkrUpIb7SPQGna17oVRLIdZXOimAoyVMKmqy0ib/RFo0P ClAEkrmWfIpA2cCi2pXXv4Rd0ckFozGj/FVVFfQDpmMTnSSf1v37YQpuuO3Z7WdDfrdpKiuSa48DD ALg36cHEdSjI00BEshjSa81a+h0NO+oi8ciSHnhamtFFTjnr6r8GQ8UcIpiTD55Q/NMrEfJcjrgLo joVDIIVtQARShDgLCL4A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGhQ8-0007vr-8n; Wed, 17 Apr 2019 10:04:00 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGhQ4-0007uF-Ft for linux-arm-kernel@lists.infradead.org; Wed, 17 Apr 2019 10:03:57 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 13106374; Wed, 17 Apr 2019 03:03:56 -0700 (PDT) Received: from mbp (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 23D433F68F; Wed, 17 Apr 2019 03:03:53 -0700 (PDT) Date: Wed, 17 Apr 2019 11:03:51 +0100 From: Catalin Marinas To: Russell King - ARM Linux admin Subject: Re: [PATCH 1/1] arm: mm: Export __sync_icache_dcache() for xen-privcmd Message-ID: <20190417100351.oix3df7hwwivgf7k@mbp> References: <20190413163052.11407-1-xypron.glpk@gmx.de> <20190415055109.GB9279@infradead.org> <20190417094137.2gkbtinldiwbkvwy@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190417094137.2gkbtinldiwbkvwy@shell.armlinux.org.uk> User-Agent: NeoMutt/20170113 (1.7.2) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190417_030356_536615_BA1BE140 X-CRM114-Status: GOOD ( 16.09 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Arnd Bergmann , Heinrich Schuchardt , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 17, 2019 at 10:41:37AM +0100, Russell King wrote: > On Sun, Apr 14, 2019 at 10:51:09PM -0700, Christoph Hellwig wrote: > > On Sat, Apr 13, 2019 at 06:30:52PM +0200, Heinrich Schuchardt wrote: > > > This patch avoids > > > ERROR: "__sync_icache_dcache" [drivers/xen/xen-privcmd.ko] undefined! > > > observed when compiling v4.19.34. > > > > > > The xen-privcmd driver, which can be modular, calls set_pte_at() > > > which in turn may call __sync_icache_dcache(). > > > > Maybe that really is a sign that it should not be modular.. > > This issue has been discussed several times, and this URL gives a list > of all messages on linux-arm-kernel that mention __sync_icache_dcache: > > https://archive.armlinux.org.uk/lurker/search/20380101.000000.00000000@ml:linux-arm-kernel,sb:__sync_icache_dcache.en.html > > At the beginning of March, Boris Ostrovsky pointed that another solution > is available that does not need architecture private symbols to be > exported. > > Since I've already said in a previous thread that I don't want this > function exported, it seems the way forward is pretty obvious. Arnd submitted a patch, not sure what happened to it: https://lore.kernel.org/lkml/20190304204826.2414365-1-arnd@arndb.de/ I think this boils down to whether set_pte_at() is allowed to be called from loadable modules. If yes, __sync_icache_dcache() needs exporting, otherwise Arnd's patch makes the relevant code built-in (and, if merged, I'm happy to revert the similar export on arm64). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel