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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7A509C4167B for ; Tue, 8 Dec 2020 17:42:54 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 3688B23B3E for ; Tue, 8 Dec 2020 17:42:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3688B23B3E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 80B0889AB7; Tue, 8 Dec 2020 17:42:53 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7157789AB7; Tue, 8 Dec 2020 17:42:52 +0000 (UTC) Date: Tue, 8 Dec 2020 19:42:46 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607449372; bh=BftUl2M64lQHtLnTxOiHMi7sfSYR5CWaxkC+KmCM7iA=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=CboFcSX9DF/ccKwCw3g3G7AMkHU6RwGXd6EhUwYLarUVQmQqkTTu1hVbbYLlT9Pu4 6ol3agoXGVmewMw36lEqKoJV2CxCo7MeHPX6SQIZt76KJ4zyKEtJBRPW/dPshNI1r5 OIKqh783vTlDFY1ymcE4sZNQ+/omhudZi2YeZJlsOTyERbDfj/+SjNI7ixm/dNByUS LV0ahU5geeb5mURgtpNiMSdgO6HExtXNo8W5419tfGmGseHd8v5j9k3Ps0NBsH3SAe LoGGh7Ckb8QT9z461GlIqQ9Gxy8zvmI5g2vRz+3KXv5BXZcFOjLKSHU8bpHY1QlW7/ CU+tRnzAJpCRQ== From: Jarkko Sakkinen To: Jason Gunthorpe Subject: Re: [PATCH v3 3/4] tpm_tis: Disable interrupts if interrupt storm detected Message-ID: <20201208174246.GB58213@kernel.org> References: <20201205014340.148235-1-jsnitsel@redhat.com> <20201205014340.148235-4-jsnitsel@redhat.com> <87tusy7n3b.fsf@nanos.tec.linutronix.de> <20201207192803.GH5487@ziepe.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201207192803.GH5487@ziepe.ca> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org, Jerry Snitselaar , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, James Bottomley , Hans de Goede , Matthew Garrett , linux-integrity@vger.kernel.org, Thomas Gleixner , Peter Huewe Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, Dec 07, 2020 at 03:28:03PM -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. > > Jason +1 for removing it. /Jarkko _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel