Re: [PATCH v1 11/12] fpga: expose hardware error info in sysfs

Tom Rix
2020-09-06T17:06:27Z

On 9/4/20 4:53 PM, Russ Weight wrote:
> Extend the Intel Security Manager class driver to include
> an optional update/hw_errinfo sysfs node that can be used
> to retrieve 64 bits of device specific error information
> following a secure update failure.
>
> The underlying driver must provide a get_hw_errinfo() callback
> function to enable this feature. This data is treated as
> opaque by the class driver. It is left to user-space software
> or support personnel to interpret this data.
>
> Signed-off-by: Russ Weight <russell.h.weight@intel.com>
> Reviewed-by: Wu Hao <hao.wu@intel.com>
> ---
> .../ABI/testing/sysfs-class-ifpga-sec-mgr | 14 +++++++
> drivers/fpga/ifpga-sec-mgr.c | 38 +++++++++++++++++++
> include/linux/fpga/ifpga-sec-mgr.h | 5 +++
> 3 files changed, 57 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> index 762a7dee9453..20bde1abb5e4 100644
> --- a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> +++ b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> @@ -135,3 +135,17 @@ Description: Read-only. Returns a string describing the failure
> idle state. If this file is read while a secure
> update is in progress, then the read will fail with
> EBUSY.
> +
> +What: /sys/class/ifpga_sec_mgr/ifpga_secX/update/hw_errinfo
> +Date: Sep 2020
> +KernelVersion: 5.10
> +Contact: Russ Weight <russell.h.weight@intel.com>
> +Description: Read-only. Returns a 64 bit error value providing
> + hardware specific information that may be useful in
> + debugging errors that occur during FPGA image updates.
> + This file is only visible if the underlying device
> + supports it. The hw_errinfo value is only accessible
> + when the secure update engine is in the idle state.
> + If this file is read while a secure update is in
> + progress, then the read will fail with EBUSY.
> + Format: "0x%llx".
> diff --git a/drivers/fpga/ifpga-sec-mgr.c b/drivers/fpga/ifpga-sec-mgr.c
> index afd97c135ebe..6944396eff80 100644
> --- a/drivers/fpga/ifpga-sec-mgr.c
> +++ b/drivers/fpga/ifpga-sec-mgr.c
> @@ -152,10 +152,17 @@ static void set_error(struct ifpga_sec_mgr *imgr, enum ifpga_sec_err err_code)
> imgr->err_code = err_code;
> }
>
> +static void set_hw_errinfo(struct ifpga_sec_mgr *imgr)
> +{
> + if (imgr->iops->get_hw_errinfo)
> + imgr->hw_errinfo = imgr->iops->get_hw_errinfo(imgr);
> +}
> +
> static void ifpga_sec_dev_error(struct ifpga_sec_mgr *imgr,
> enum ifpga_sec_err err_code)
> {
> set_error(imgr, err_code);
> + set_hw_errinfo(imgr);
> imgr->iops->cancel(imgr);
> }
>
> @@ -348,6 +355,23 @@ error_show(struct device *dev, struct device_attribute *attr, char *buf)
> }
> static DEVICE_ATTR_RO(error);
>
> +static ssize_t
> +hw_errinfo_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
> + int ret;
> +
> + mutex_lock(&imgr->lock);
> + if (imgr->progress != IFPGA_SEC_PROG_IDLE)
> + ret = -EBUSY;
> + else
> + ret = sprintf(buf, "0x%llx\n", imgr->hw_errinfo);
> + mutex_unlock(&imgr->lock);
> +
> + return ret;
> +}
> +static DEVICE_ATTR_RO(hw_errinfo);
> +
> static ssize_t remaining_size_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> @@ -382,6 +406,7 @@ static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
> imgr->filename[strlen(imgr->filename) - 1] = '\0';
>
> imgr->err_code = IFPGA_SEC_ERR_NONE;
> + imgr->hw_errinfo = 0;
> imgr->request_cancel = false;
> imgr->progress = IFPGA_SEC_PROG_READ_FILE;
> reinit_completion(&imgr->update_done);
> @@ -416,18 +441,31 @@ static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
> }
> static DEVICE_ATTR_WO(cancel);
>
> +static umode_t
> +sec_mgr_update_visible(struct kobject *kobj, struct attribute *attr, int n)
> +{
> + struct ifpga_sec_mgr *imgr = to_sec_mgr(kobj_to_dev(kobj));
> +
> + if (attr == &dev_attr_hw_errinfo.attr && !imgr->iops->get_hw_errinfo)
> + return 0;
> +
> + return attr->mode;
> +}
> +
> static struct attribute *sec_mgr_update_attrs[] = {
> &dev_attr_filename.attr,
> &dev_attr_cancel.attr,
> &dev_attr_status.attr,
> &dev_attr_error.attr,
> &dev_attr_remaining_size.attr,
> + &dev_attr_hw_errinfo.attr,
> NULL,
> };
>
> static struct attribute_group sec_mgr_update_attr_group = {
> .name = "update",
> .attrs = sec_mgr_update_attrs,
> + .is_visible = sec_mgr_update_visible,
> };
>
> static ssize_t name_show(struct device *dev,
> diff --git a/include/linux/fpga/ifpga-sec-mgr.h b/include/linux/fpga/ifpga-sec-mgr.h
> index f51ed663a723..3be8d8da078a 100644
> --- a/include/linux/fpga/ifpga-sec-mgr.h
> +++ b/include/linux/fpga/ifpga-sec-mgr.h
> @@ -135,6 +135,9 @@ enum ifpga_sec_err {
> * function and is called at the completion
> * of the update, whether success or failure,
> * if the prepare function succeeded.
> + * @get_hw_errinfo: Optional: Return u64 hw specific error info.
> + * The software err_code may used to determine
> + * whether the hw error info is applicable.
> */
> struct ifpga_sec_mgr_ops {
> sysfs_cnt_hndlr_t user_flash_count;
> @@ -158,6 +161,7 @@ struct ifpga_sec_mgr_ops {
> enum ifpga_sec_err (*poll_complete)(struct ifpga_sec_mgr *imgr);
> void (*cleanup)(struct ifpga_sec_mgr *imgr);
> enum ifpga_sec_err (*cancel)(struct ifpga_sec_mgr *imgr);
> + u64 (*get_hw_errinfo)(struct ifpga_sec_mgr *imgr);
> };
>
> /* Update progress codes */
> @@ -183,6 +187,7 @@ struct ifpga_sec_mgr {
> enum ifpga_sec_prog progress;
> enum ifpga_sec_prog err_state; /* progress state at time of failure */
> enum ifpga_sec_err err_code; /* security manager error code */
> + u64 hw_errinfo; /* 64 bits of HW specific error info */
> bool request_cancel;
> bool driver_unload;
> void *priv;

This looks fine.

Reviewed-by: Tom Rix <trix@redhat.com>