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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D8B85C433ED for ; Mon, 17 May 2021 09:31:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B483560E09 for ; Mon, 17 May 2021 09:31:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235977AbhEQJdM (ORCPT ); Mon, 17 May 2021 05:33:12 -0400 Received: from mx2.suse.de ([195.135.220.15]:36312 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235863AbhEQJdL (ORCPT ); Mon, 17 May 2021 05:33:11 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1621243914; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tA3XRwdT8ok6d1059+xvA8E+I4telJ7GeyBKUaR4o14=; b=mAhY5yhHPYD3W2hP39/fxKfs6wNBqpydeAo2pLbRj/XbaPdsPUkMCt6xWN9nmg3GUvnzvm wr5LGulJL3xSZQwJhPg0+IBh/7/6VEr9qNracpZIJ+ImNiIFacbG2ajapD5UzViYA/wdy1 EEOK7ksb34J50ytZqhi9FMnaPebwk5s= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 372A5B05C; Mon, 17 May 2021 09:31:54 +0000 (UTC) Subject: Re: [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled To: Connor Davis Cc: Jann Horn , Lee Jones , Chunfeng Yun , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Greg Kroah-Hartman References: From: Jan Beulich Message-ID: <8ccce25a-e3ca-cb30-f6a3-f9243a85a49b@suse.com> Date: Mon, 17 May 2021 11:32:01 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14.05.2021 02:56, Connor Davis wrote: > Check if the debug capability is enabled in early_xdbc_parse_parameter, > and if it is, return with an error. This avoids collisions with whatever > enabled the DbC prior to linux starting. Doesn't this go too far and prevent use even if firmware (perhaps mistakenly) left it enabled? Jan > Signed-off-by: Connor Davis > --- > drivers/usb/early/xhci-dbc.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c > index be4ecbabdd58..ca67fddc2d36 100644 > --- a/drivers/usb/early/xhci-dbc.c > +++ b/drivers/usb/early/xhci-dbc.c > @@ -642,6 +642,16 @@ int __init early_xdbc_parse_parameter(char *s) > } > xdbc.xdbc_reg = (struct xdbc_regs __iomem *)(xdbc.xhci_base + offset); > > + if (readl(&xdbc.xdbc_reg->control) & CTRL_DBC_ENABLE) { > + pr_notice("xhci debug capability already in use\n"); > + early_iounmap(xdbc.xhci_base, xdbc.xhci_length); > + xdbc.xdbc_reg = NULL; > + xdbc.xhci_base = NULL; > + xdbc.xhci_length = 0; > + > + return -ENODEV; > + } > + > return 0; > } > >