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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62F90C4332F for ; Mon, 29 Nov 2021 22:14:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233814AbhK2WRn (ORCPT ); Mon, 29 Nov 2021 17:17:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232748AbhK2WQo (ORCPT ); Mon, 29 Nov 2021 17:16:44 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2805C08ED8F; Mon, 29 Nov 2021 10:20:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 36E5CCE13D5; Mon, 29 Nov 2021 18:20:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5BF5C53FC7; Mon, 29 Nov 2021 18:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638210048; bh=62zfnLtY6sigOaOUyXC1QYoLen+uqHrw7HKSLpKKm1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hQTGLzpwakyDTyHriTee8vNe/1rhNZ4nnqdGyrHmhVPl6X41oNDzvjaVisgEcwT+r B8rn6OJIgAJ9YNd0hw+pGnS1Oh6pzHasXS+ez/YRkLILODHuBricW4fu4sd5QJvbKp yb5UF4fxS32ZdKeibEjYgEx70+aGuXzMyrocOd9s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Pali=20Roh=C3=A1r?= , Lorenzo Pieralisi , =?UTF-8?q?Marek=20Beh=C3=BAn?= Subject: [PATCH 4.19 24/69] PCI: aardvark: Dont touch PCIe registers if no card connected Date: Mon, 29 Nov 2021 19:18:06 +0100 Message-Id: <20211129181704.463324459@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211129181703.670197996@linuxfoundation.org> References: <20211129181703.670197996@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pali Rohár commit 70e380250c3621c55ff218cbaf2272830d9dbb1d upstream. When there is no PCIe card connected and advk_pcie_rd_conf() or advk_pcie_wr_conf() is called for PCI bus which doesn't belong to emulated root bridge, the aardvark driver throws the following error message: advk-pcie d0070000.pcie: config read/write timed out Obviously accessing PCIe registers of disconnected card is not possible. Extend check in advk_pcie_valid_device() function for validating availability of PCIe bus. If PCIe link is down, then the device is marked as Not Found and the driver does not try to access these registers. This is just an optimization to prevent accessing PCIe registers when card is disconnected. Trying to access PCIe registers of disconnected card does not cause any crash, kernel just needs to wait for a timeout. So if card disappear immediately after checking for PCIe link (before accessing PCIe registers), it does not cause any problems. Link: https://lore.kernel.org/r/20200702083036.12230-1-pali@kernel.org Signed-off-by: Pali Rohár Signed-off-by: Lorenzo Pieralisi Signed-off-by: Marek Behún Signed-off-by: Greg Kroah-Hartman --- drivers/pci/controller/pci-aardvark.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -525,6 +525,13 @@ static bool advk_pcie_valid_device(struc if ((bus->number == pcie->root_bus_nr) && PCI_SLOT(devfn) != 0) return false; + /* + * If the link goes down after we check for link-up, nothing bad + * happens but the config access times out. + */ + if (bus->number != pcie->root_bus_nr && !advk_pcie_link_up(pcie)) + return false; + return true; }