From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C1A4119B3FF; Tue, 15 Oct 2024 11:59:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728993557; cv=none; b=OosSt/dPJ9ewnDlVKjZ1cLqdKoD+XjqZWqJg5iJoUBDUlHdzJ+SVfroBQBS3PwNyiIsX5nDPoF3/HcGeE5Dj8P94NNZQp4SuUrJ1+xSoJNdjPMIxhHA+bTEHut20kBYw4cRWzVYXF3nlnhXNlP5TJLTcAqN4Vw2CmIqPYhNT3Nk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728993557; c=relaxed/simple; bh=nIsIsKQmdKZ2QIxFLjJJO9DodOvXIgc4GJtxEF6NmdA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pWmQq4Wj5TjMsXXrIXXZrtMNIAri3VeBTqwMA2qKJJEYVON6JxP1223jttEBVQTmq57MM97qzZ0KzsdVxJUrSBJNQzhsYWWH4hoLvj9GAQTeJ2TEyz3sDbGDQaYINwEQXsvZ8ImvC4vfp7gpvhFJC5tMNLjukwnRN8jgJlSEaQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yBtDF0qQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yBtDF0qQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27F66C4CEC6; Tue, 15 Oct 2024 11:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728993557; bh=nIsIsKQmdKZ2QIxFLjJJO9DodOvXIgc4GJtxEF6NmdA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yBtDF0qQEdsQj6qOkJhCWjXVNrrbu5yRCaN/CfVoI4d3u/kDGBxufhWoJ4AWLeO3R lSKZf8rH/Wep79v078iZ+LC4bbDlUdjfR38HvRBO4p/tbL7pA4Wul+mIBmRZBdVhZd 6KXgtdJpicUJzduRV2Bd9GHtWh7THBhv1a9q/Tu4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marc Gonzalez , Caleb Connolly , Bjorn Andersson , Will Deacon , Sasha Levin Subject: [PATCH 5.15 446/691] iommu/arm-smmu-qcom: hide last LPASS SMMU context bank from linux Date: Tue, 15 Oct 2024 13:26:34 +0200 Message-ID: <20241015112458.050543392@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015112440.309539031@linuxfoundation.org> References: <20241015112440.309539031@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marc Gonzalez [ Upstream commit 3a8990b8a778219327c5f8ecf10b5d81377b925a ] On qcom msm8998, writing to the last context bank of lpass_q6_smmu (base address 0x05100000) produces a system freeze & reboot. The hardware/hypervisor reports 13 context banks for the LPASS SMMU on msm8998, but only the first 12 are accessible... Override the number of context banks [ 2.546101] arm-smmu 5100000.iommu: probing hardware configuration... [ 2.552439] arm-smmu 5100000.iommu: SMMUv2 with: [ 2.558945] arm-smmu 5100000.iommu: stage 1 translation [ 2.563627] arm-smmu 5100000.iommu: address translation ops [ 2.568923] arm-smmu 5100000.iommu: non-coherent table walk [ 2.574566] arm-smmu 5100000.iommu: (IDR0.CTTW overridden by FW configuration) [ 2.580220] arm-smmu 5100000.iommu: stream matching with 12 register groups [ 2.587263] arm-smmu 5100000.iommu: 13 context banks (0 stage-2 only) [ 2.614447] arm-smmu 5100000.iommu: Supported page sizes: 0x63315000 [ 2.621358] arm-smmu 5100000.iommu: Stage-1: 36-bit VA -> 36-bit IPA [ 2.627772] arm-smmu 5100000.iommu: preserved 0 boot mappings Specifically, the crashes occur here: qsmmu->bypass_cbndx = smmu->num_context_banks - 1; arm_smmu_cb_write(smmu, qsmmu->bypass_cbndx, ARM_SMMU_CB_SCTLR, 0); and here: arm_smmu_write_context_bank(smmu, i); arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_FSR, ARM_SMMU_CB_FSR_FAULT); It is likely that FW reserves the last context bank for its own use, thus a simple work-around is: DON'T USE IT in Linux. If we decrease the number of context banks, last one will be "hidden". Signed-off-by: Marc Gonzalez Reviewed-by: Caleb Connolly Reviewed-by: Bjorn Andersson Link: https://lore.kernel.org/r/20240820-smmu-v3-1-2f71483b00ec@freebox.fr Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c index 272c9b35c9f0e..da249140ed2a1 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c @@ -254,6 +254,13 @@ static int qcom_smmu_cfg_probe(struct arm_smmu_device *smmu) u32 smr; int i; + /* + * MSM8998 LPASS SMMU reports 13 context banks, but accessing + * the last context bank crashes the system. + */ + if (of_device_is_compatible(smmu->dev->of_node, "qcom,msm8998-smmu-v2") && smmu->num_context_banks == 13) + smmu->num_context_banks = 12; + /* * Some platforms support more than the Arm SMMU architected maximum of * 128 stream matching groups. For unknown reasons, the additional -- 2.43.0