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Date:   Tue, 16 Jun 2020 18:20:19 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Shiju Jose <shiju.jose@huawei.com>
Cc:     linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, rjw@rjwysocki.net, bp@alien8.de,
        james.morse@arm.com, lenb@kernel.org, tony.luck@intel.com,
        dan.carpenter@oracle.com, zhangliguang@linux.alibaba.com,
        andriy.shevchenko@linux.intel.com, wangkefeng.wang@huawei.com,
        jroedel@suse.de, yangyicong@hisilicon.com,
        jonathan.cameron@huawei.com, tanxiaofei@huawei.com
Subject: Re: [PATCH v9 2/2] PCI: hip: Add handling of HiSilicon HIP PCIe
 controller errors
Message-ID: <20200616232019.GA1987909@bjorn-Precision-5520>
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In-Reply-To: <20200615101552.802-3-shiju.jose@huawei.com>
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On Mon, Jun 15, 2020 at 11:15:52AM +0100, Shiju Jose wrote:
> From: Yicong Yang <yangyicong@hisilicon.com>
> 
> The HiSilicon HIP PCIe controller is capable of handling errors
> on root port and perform port reset separately at each root port.
> 
> Add error handling driver for HIP PCIe controller to log
> and report recoverable errors. Perform root port reset and restore
> link status after the recovery.
> 
> Following are some of the PCIe controller's recoverable errors
> 1. completion transmission timeout error.
> 2. CRS retry counter over the threshold error.
> 3. ECC 2 bit errors
> 4. AXI bresponse/rresponse errors etc.

> +static int hisi_pcie_notify_error(struct notifier_block *nb,
> +				  unsigned long event, void *data)
> +{
> +	struct acpi_hest_generic_data *gdata = data;
> +	const struct hisi_pcie_error_data *error_data =
> +				acpi_hest_get_payload(gdata);
> +	struct hisi_pcie_error_private *priv =
> +			container_of(nb, struct hisi_pcie_error_private, nb);
> +	struct platform_device *pdev = priv->pdev;
> +	struct device *dev = &pdev->dev;
> +	u8 socket;
> +
> +	if (device_property_read_u8(dev, "socket", &socket))
> +		return NOTIFY_DONE;
> +
> +	if (!guid_equal((guid_t *)gdata->section_type, &hisi_pcie_sec_type) ||
> +	    error_data->socket_id != socket)
> +		return NOTIFY_DONE;

I think you have to verify the GUID first before you can even safely
extract a struct hisi_pcie_error_private from the payload:

  if (!guid_equal(...))
    return NOTIFY_DONE;

  priv = container_of(nb, struct hisi_pcie_error_private, nb);
  pdev = priv->pdev;
  dev = &pdev->dev;

  if (device_property_read_u8(dev, "socket", &socket))
    return NOTIFY_DONE;

  if (error_data->socket_id != socket)
    return NOTIFY_DONE;

> +	hisi_pcie_handle_error(pdev, error_data);
> +
> +	return NOTIFY_OK;
> +}