Re: [PATCH v1 08/12] fpga: expose sec-mgr update errors

Tom Rix
2020-09-06T16:28:05Z

On 9/4/20 4:53 PM, Russ Weight wrote:
> Extend Intel Security Manager class driver to include
> an update/error sysfs node that can be read for error
> information when a secure update fails.
>
> 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 | 17 ++++++
> drivers/fpga/ifpga-sec-mgr.c | 60 +++++++++++++++++--
> include/linux/fpga/ifpga-sec-mgr.h | 1 +
> 3 files changed, 73 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> index 849ccb2802f8..e7b1b02bf7ee 100644
> --- a/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> +++ b/Documentation/ABI/testing/sysfs-class-ifpga-sec-mgr
> @@ -97,3 +97,20 @@ Description: Read-only. Returns a string describing the current
> programming. Userspace code can poll on this file,
> as it will be signaled by sysfs_notify() on each
> state change.
> +
> +What: /sys/class/ifpga_sec_mgr/ifpga_secX/update/error
> +Date: Sep 2020
> +KernelVersion: 5.10
> +Contact: Russ Weight <russell.h.weight@intel.com>
> +Description: Read-only. Returns a string describing the failure
> + of a secure update. This string will be in the form
> + of <STATUS>:<ERROR>, where <STATUS> will be one of
> + the status strings described for the status sysfs
> + file and <ERROR> will be one of the following:
> + hw-error, timeout, user-abort, device-busy,
> + invalid-file-size, read-write-error, flash-wearout,
> + file-read-error. The error sysfs file is only
> + meaningful 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.
> diff --git a/drivers/fpga/ifpga-sec-mgr.c b/drivers/fpga/ifpga-sec-mgr.c
> index 5fe3d85e2963..a7718bd8ee61 100644
> --- a/drivers/fpga/ifpga-sec-mgr.c
> +++ b/drivers/fpga/ifpga-sec-mgr.c
> @@ -146,10 +146,16 @@ static void update_progress(struct ifpga_sec_mgr *imgr,
> sysfs_notify(&imgr->dev.kobj, "update", "status");
> }
>
> +static void set_error(struct ifpga_sec_mgr *imgr, enum ifpga_sec_err err_code)
> +{
> + imgr->err_state = imgr->progress;
> + imgr->err_code = err_code;
> +}
> +
> static void ifpga_sec_dev_error(struct ifpga_sec_mgr *imgr,
> enum ifpga_sec_err err_code)
> {
> - imgr->err_code = err_code;
> + set_error(imgr, err_code);
> imgr->iops->cancel(imgr);
> }
>
> @@ -172,7 +178,7 @@ static void ifpga_sec_mgr_update(struct work_struct *work)
>
> get_device(&imgr->dev);
> if (request_firmware(&fw, imgr->filename, &imgr->dev)) {
> - imgr->err_code = IFPGA_SEC_ERR_FILE_READ;
> + set_error(imgr, IFPGA_SEC_ERR_FILE_READ);
> goto idle_exit;
> }
>
> @@ -180,7 +186,7 @@ static void ifpga_sec_mgr_update(struct work_struct *work)
> imgr->remaining_size = fw->size;
>
> if (!try_module_get(imgr->dev.parent->driver->owner)) {
> - imgr->err_code = IFPGA_SEC_ERR_BUSY;
> + set_error(imgr, IFPGA_SEC_ERR_BUSY);
> goto release_fw_exit;
> }
>
> @@ -266,16 +272,59 @@ static const char * const sec_mgr_prog_str[] = {
> "programming" /* IFPGA_SEC_PROG_PROGRAMMING */
> };
>
> +static const char * const sec_mgr_err_str[] = {
> + "none", /* IFPGA_SEC_ERR_NONE */
> + "hw-error", /* IFPGA_SEC_ERR_HW_ERROR */
> + "timeout", /* IFPGA_SEC_ERR_TIMEOUT */
> + "user-abort", /* IFPGA_SEC_ERR_CANCELED */
> + "device-busy", /* IFPGA_SEC_ERR_BUSY */
> + "invalid-file-size", /* IFPGA_SEC_ERR_INVALID_SIZE */
> + "read-write-error", /* IFPGA_SEC_ERR_RW_ERROR */
> + "flash-wearout", /* IFPGA_SEC_ERR_WEAROUT */
> + "file-read-error" /* IFPGA_SEC_ERR_FILE_READ */
> +};
> +
> +static const char *sec_progress(enum ifpga_sec_prog prog)
> +{
A consistent api would have imgr as the parameter.
> + return (prog < IFPGA_SEC_PROG_MAX) ?
> + sec_mgr_prog_str[prog] : "unknown-status";
> +}
> +
> static ssize_t
> status_show(struct device *dev, struct device_attribute *attr, char *buf)
> {
> struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
>
> - return sprintf(buf, "%s\n", (imgr->progress < IFPGA_SEC_PROG_MAX) ?
> - sec_mgr_prog_str[imgr->progress] : "unknown-status");
> + return sprintf(buf, "%s\n", sec_progress(imgr->progress));
> }
> static DEVICE_ATTR_RO(status);
>
> +static ssize_t
> +error_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> + struct ifpga_sec_mgr *imgr = to_sec_mgr(dev);
> + enum ifpga_sec_err err_code;
> + const char *prog_str;
> + int ret;
> +
> + mutex_lock(&imgr->lock);
> + if (imgr->progress != IFPGA_SEC_PROG_IDLE) {
> + ret = -EBUSY;
> + } else if (!imgr->err_code) {
> + ret = 0;
> + } else {
> + err_code = imgr->err_code;
> + prog_str = sec_progress(imgr->err_state);
> + ret = sprintf(buf, "%s:%s\n", prog_str,
> + (err_code < IFPGA_SEC_ERR_MAX) ?
> + sec_mgr_err_str[err_code] : "unknown-error");

Should have sec_error() call to match the new sec_progress()

Tom

> + }
> + mutex_unlock(&imgr->lock);
> +
> + return ret;
> +}
> +static DEVICE_ATTR_RO(error);
> +
> static ssize_t filename_store(struct device *dev, struct device_attribute *attr,
> const char *buf, size_t count)
> {
> @@ -314,6 +363,7 @@ static DEVICE_ATTR_WO(filename);
> static struct attribute *sec_mgr_update_attrs[] = {
> &dev_attr_filename.attr,
> &dev_attr_status.attr,
> + &dev_attr_error.attr,
> NULL,
> };
>
> diff --git a/include/linux/fpga/ifpga-sec-mgr.h b/include/linux/fpga/ifpga-sec-mgr.h
> index 4da2864e251c..f04bf9e30c67 100644
> --- a/include/linux/fpga/ifpga-sec-mgr.h
> +++ b/include/linux/fpga/ifpga-sec-mgr.h
> @@ -181,6 +181,7 @@ struct ifpga_sec_mgr {
> const u8 *data; /* pointer to update data */
> u32 remaining_size; /* size remaining to transfer */
> 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 */
> bool driver_unload;
> void *priv;