From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8F2E1267701; Thu, 13 Mar 2025 13:07:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741871229; cv=none; b=URLBvAtyUqRz4z6hs/RxDx0fX6tG4gGWkCx5zFjkgaLCb2JaSLxYASce7ZqyfJhte5RnVvl+G0ewh0H+LGnE4Wzf7lCYNLruKnt3zUOVNbcALdaePEyeChcZuoLmW69I6kwX3KY2XjGksNBEAI/77/VMGFnyU/IjAoAP9M4HnI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741871229; c=relaxed/simple; bh=IZFUBqt/PcENGjFiftwrfryoSFoDuDYzzj7uu2pIxSE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EB8vt2lx9bLbjFB4y/K5GaNAgi3xmqyO5BcsH2k1EPxqZFpRXz8/SOWPtWjyQAdaGFDaZXss1V7zqKcjxVFDGzSRo8cmYenKdzG7Z/riVpwoYA5L4uPP+4TMydpwhuRxYZ+xOTClDqG2PSkx1h4Ec7tVASdBhC7rJxOVLLaXppM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EE6571C00; Thu, 13 Mar 2025 06:07:15 -0700 (PDT) Received: from [10.57.40.246] (unknown [10.57.40.246]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AA07C3F673; Thu, 13 Mar 2025 06:07:01 -0700 (PDT) Message-ID: <016bb7ca-f0d3-464e-ac74-46e6f78e90d7@arm.com> Date: Thu, 13 Mar 2025 13:06:59 +0000 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/4] iommu: Get DT/ACPI parsing into the proper probe path To: Marek Szyprowski , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , "Rafael J. Wysocki" , Len Brown , Russell King , Greg Kroah-Hartman , Danilo Krummrich , Stuart Yoder , Laurentiu Tudor , Nipun Gupta , Nikhil Agarwal , Joerg Roedel , Will Deacon , Rob Herring , Saravana Kannan , Bjorn Helgaas Cc: linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, Charan Teja Kalla References: <9b358d68-332e-404e-9a75-740297f7b28d@samsung.com> <417d6f59-0d78-4e81-ad0b-e06846f786b0@arm.com> From: Robin Murphy Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2025-03-13 12:23 pm, Marek Szyprowski wrote: > On 13.03.2025 12:01, Robin Murphy wrote: >> On 2025-03-13 9:56 am, Marek Szyprowski wrote: >> [...] >>> This patch landed in yesterday's linux-next as commit bcb81ac6ae3c >>> ("iommu: Get DT/ACPI parsing into the proper probe path"). In my tests I >>> found it breaks booting of ARM64 RK3568-based Odroid-M1 board >>> (arch/arm64/boot/dts/rockchip/rk3568-odroid-m1.dts). Here is the >>> relevant kernel log: >> >> ...and the bug-flushing-out begins! >> >>> Unable to handle kernel NULL pointer dereference at virtual address >>> 00000000000003e8 >>> Mem abort info: >>>     ESR = 0x0000000096000004 >>>     EC = 0x25: DABT (current EL), IL = 32 bits >>>     SET = 0, FnV = 0 >>>     EA = 0, S1PTW = 0 >>>     FSC = 0x04: level 0 translation fault >>> Data abort info: >>>     ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 >>>     CM = 0, WnR = 0, TnD = 0, TagAccess = 0 >>>     GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 >>> [00000000000003e8] user address but active_mm is swapper >>> Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP >>> Modules linked in: >>> CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc3+ #15533 >>> Hardware name: Hardkernel ODROID-M1 (DT) >>> pstate: 00400009 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) >>> pc : devm_kmalloc+0x2c/0x114 >>> lr : rk_iommu_of_xlate+0x30/0x90 >>> ... >>> Call trace: >>>    devm_kmalloc+0x2c/0x114 (P) >>>    rk_iommu_of_xlate+0x30/0x90 >> >> Yeah, looks like this is doing something a bit questionable which can't >> work properly. TBH the whole dma_dev thing could probably be cleaned up >> now that we have proper instances, but for now does this work? > > Yes, this patch fixes the problem I've observed. > > Reported-by: Marek Szyprowski > Tested-by: Marek Szyprowski > > BTW, this dma_dev idea has been borrowed from my exynos_iommu driver and > I doubt it can be cleaned up. On the contrary I suspect they both can - it all dates back to when we had the single global platform bus iommu_ops and the SoC drivers were forced to bodge their own notion of multiple instances, but with the modern core code, ops are always called via a valid IOMMU instance or domain, so in principle it should always be possible to get at an appropriate IOMMU device now. IIRC it was mostly about allocating and DMA-mapping the pagetables in domain_alloc, where the private notion of instances didn't have enough information, but domain_alloc_paging solves that. Cheers, Robin.