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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 3C134C433FE for ; Mon, 7 Dec 2020 19:59:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E96E42368A for ; Mon, 7 Dec 2020 19:59:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725924AbgLGT72 (ORCPT ); Mon, 7 Dec 2020 14:59:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725808AbgLGT71 (ORCPT ); Mon, 7 Dec 2020 14:59:27 -0500 Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [IPv6:2607:fcd0:100:8a00::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E2D7C061749; Mon, 7 Dec 2020 11:58:47 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 9E3691280221; Mon, 7 Dec 2020 11:58:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1607371125; bh=k/Dd2cYrK28lrZ2qpukQjOHheuWRRxKEAwCopHSG05E=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=oWAhxkXjg6qRXeEQo0LSHh69muuIN//JVI5b76pfiGzTOFOSiSeerHyhJYkd13aLz vV+mTEvXUo0Xm5JPQSxmzIg7QGeHJurbI1samrBMs2MT85XklMBErr+1vtwRlr9RbH Mr1O+RF9DmddGa9u2oJf1yAmPZX/oNkCTcDqY9fQ= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id S1wle3Jxpi4d; Mon, 7 Dec 2020 11:58:45 -0800 (PST) Received: from jarvis.int.hansenpartnership.com (unknown [IPv6:2601:600:8280:66d1::527]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id E939C128021B; Mon, 7 Dec 2020 11:58:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1607371125; bh=k/Dd2cYrK28lrZ2qpukQjOHheuWRRxKEAwCopHSG05E=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=oWAhxkXjg6qRXeEQo0LSHh69muuIN//JVI5b76pfiGzTOFOSiSeerHyhJYkd13aLz vV+mTEvXUo0Xm5JPQSxmzIg7QGeHJurbI1samrBMs2MT85XklMBErr+1vtwRlr9RbH Mr1O+RF9DmddGa9u2oJf1yAmPZX/oNkCTcDqY9fQ= Message-ID: Subject: Re: [PATCH v3 3/4] tpm_tis: Disable interrupts if interrupt storm detected From: James Bottomley To: Jason Gunthorpe , Thomas Gleixner Cc: Jerry Snitselaar , linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Jarkko Sakkinen , Peter Huewe , Matthew Garrett , Hans de Goede Date: Mon, 07 Dec 2020 11:58:44 -0800 In-Reply-To: <20201207192803.GH5487@ziepe.ca> References: <20201205014340.148235-1-jsnitsel@redhat.com> <20201205014340.148235-4-jsnitsel@redhat.com> <87tusy7n3b.fsf@nanos.tec.linutronix.de> <20201207192803.GH5487@ziepe.ca> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Mon, 2020-12-07 at 15:28 -0400, Jason Gunthorpe wrote: > On Sun, Dec 06, 2020 at 08:26:16PM +0100, Thomas Gleixner wrote: > > Just as a side note. I was looking at tpm_tis_probe_irq_single() > > and that function is leaking the interrupt request if any of the > > checks afterwards fails, except for the final interrupt probe check > > which does a cleanup. That means on fail before that the interrupt > > handler stays requested up to the point where the module is > > removed. If that's a shared interrupt and some other device is > > active on the same line, then each interrupt from that device will > > call into the TPM code. Something like the below is needed. > > > > Also the X86 autoprobe mechanism is interesting: > > > > if (IS_ENABLED(CONFIG_X86)) > > for (i = 3; i <= 15; i++) > > if (!tpm_tis_probe_irq_single(chip, intmask, 0, > > i)) > > return; > > > > The third argument is 'flags' which is handed to request_irq(). So > > that won't ever be able to probe a shared interrupt. But if an > > interrupt number > 0 is handed to tpm_tis_core_init() the interrupt > > is requested with IRQF_SHARED. Same issue when the chip has an > > interrupt number in the register. It's also requested exclusive > > which is pretty likely to fail on ancient x86 machines. > > It is very likely none of this works any more, it has been repeatedly > reworked over the years and just left behind out of fear someone > needs it. I've thought it should be deleted for a while now. > > I suppose the original logic was to try and probe without SHARED > because a probe would need exclusive access to the interrupt to tell > if the TPM was actually the source, not some other device. > > It is all very old and very out of step with current thinking, IMHO. > I skeptical that TPM interrupts were ever valuable enough to deserve > this in the first place. For what it's worth, I agree. Trying to probe all 15 ISA interrupts is last millennium thinking we should completely avoid. If it's not described in ACPI then you don't get an interrupt full stop. James