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

Russ Weight
2020-09-22T23:42:49Z

On 9/6/20 9:27 AM, Tom Rix wrote:
> 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.

There are two calls to this function: one passes imgr->progress, and one
passes imgr->err_status. For this function, passing imgr alone would be
insufficient.
>> + 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()
OK - I'll add the sec_error() function.
>
> 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;