[PATCH v5 4/7] fpga: sec-mgr: expose sec-mgr update errors

Russ Weight
2020-10-21T00:17:25Z

Extend the FPGA 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: Tom Rix <trix@redhat.com>
---
v5:
- Use new function sysfs_emit() in the error_show() function
v4:
- Changed from "Intel FPGA Security Manager" to FPGA Security Manager"
and removed unnecessary references to "Intel".
- Changed: iops -> sops, imgr -> smgr, IFPGA_ -> FPGA_, ifpga_ to fpga_
v3:
- Use dev_err() for invalid error code in sec_error()
v2:
- Bumped documentation date and version
- Added warning to sec_progress() for invalid progress status
- Added sec_error() function (similar to sec_progress())
---
.../ABI/testing/sysfs-class-fpga-sec-mgr | 17 ++++
drivers/fpga/fpga-sec-mgr.c | 83 ++++++++++++++++---
include/linux/fpga/fpga-sec-mgr.h | 1 +
3 files changed, 89 insertions(+), 12 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
index 69b4cf7e1cd4..560513653c70 100644
--- a/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
+++ b/Documentation/ABI/testing/sysfs-class-fpga-sec-mgr
@@ -89,3 +89,20 @@ 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/fpga_sec_mgr/fpga_secX/update/error
+Date: Oct 2020
+KernelVersion: 5.11
+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/fpga-sec-mgr.c b/drivers/fpga/fpga-sec-mgr.c
index 65b89248bd85..54f3713ba64c 100644
--- a/drivers/fpga/fpga-sec-mgr.c
+++ b/drivers/fpga/fpga-sec-mgr.c
@@ -150,10 +150,16 @@ static void update_progress(struct fpga_sec_mgr *smgr,
sysfs_notify(&smgr->dev.kobj, "update", "status");
}

+static void set_error(struct fpga_sec_mgr *smgr, enum fpga_sec_err err_code)
+{
+ smgr->err_state = smgr->progress;
+ smgr->err_code = err_code;
+}
+
static void fpga_sec_dev_error(struct fpga_sec_mgr *smgr,
enum fpga_sec_err err_code)
{
- smgr->err_code = err_code;
+ set_error(smgr, err_code);
smgr->sops->cancel(smgr);
}

@@ -176,7 +182,7 @@ static void fpga_sec_mgr_update(struct work_struct *work)

get_device(&smgr->dev);
if (request_firmware(&fw, smgr->filename, &smgr->dev)) {
- smgr->err_code = FPGA_SEC_ERR_FILE_READ;
+ set_error(smgr, FPGA_SEC_ERR_FILE_READ);
goto idle_exit;
}

@@ -184,7 +190,7 @@ static void fpga_sec_mgr_update(struct work_struct *work)
smgr->remaining_size = fw->size;

if (!try_module_get(smgr->dev.parent->driver->owner)) {
- smgr->err_code = FPGA_SEC_ERR_BUSY;
+ set_error(smgr, FPGA_SEC_ERR_BUSY);
goto release_fw_exit;
}

@@ -276,24 +282,76 @@ static const char * const sec_mgr_prog_str[] = {
"programming" /* FPGA_SEC_PROG_PROGRAMMING */
};

-static ssize_t
-status_show(struct device *dev, struct device_attribute *attr, char *buf)
+static const char * const sec_mgr_err_str[] = {
+ "none", /* FPGA_SEC_ERR_NONE */
+ "hw-error", /* FPGA_SEC_ERR_HW_ERROR */
+ "timeout", /* FPGA_SEC_ERR_TIMEOUT */
+ "user-abort", /* FPGA_SEC_ERR_CANCELED */
+ "device-busy", /* FPGA_SEC_ERR_BUSY */
+ "invalid-file-size", /* FPGA_SEC_ERR_INVALID_SIZE */
+ "read-write-error", /* FPGA_SEC_ERR_RW_ERROR */
+ "flash-wearout", /* FPGA_SEC_ERR_WEAROUT */
+ "file-read-error" /* FPGA_SEC_ERR_FILE_READ */
+};
+
+static const char *sec_progress(struct device *dev, enum fpga_sec_prog prog)
{
- struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
const char *status = "unknown-status";
- enum fpga_sec_prog progress;

- progress = smgr->progress;
- if (progress < FPGA_SEC_PROG_MAX)
- status = sec_mgr_prog_str[progress];
+ if (prog < FPGA_SEC_PROG_MAX)
+ status = sec_mgr_prog_str[prog];
else
dev_err(dev, "Invalid status during secure update: %d\n",
- progress);
+ prog);
+
+ return status;
+}
+
+static const char *sec_error(struct device *dev, enum fpga_sec_err err_code)
+{
+ const char *error = "unknown-error";
+
+ if (err_code < FPGA_SEC_ERR_MAX)
+ error = sec_mgr_err_str[err_code];
+ else
+ dev_err(dev, "Invalid error code during secure update: %d\n",
+ err_code);
+
+ return error;
+}
+
+static ssize_t
+status_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct fpga_sec_mgr *smgr = to_sec_mgr(dev);

- return sysfs_emit(buf, "%s\n", status);
+ return sysfs_emit(buf, "%s\n", sec_progress(dev, smgr->progress));
}
static DEVICE_ATTR_RO(status);

+static ssize_t
+error_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct fpga_sec_mgr *smgr = to_sec_mgr(dev);
+ int ret;
+
+ mutex_lock(&smgr->lock);
+
+ if (smgr->progress != FPGA_SEC_PROG_IDLE)
+ ret = -EBUSY;
+ else if (!smgr->err_code)
+ ret = 0;
+ else
+ ret = sysfs_emit(buf, "%s:%s\n",
+ sec_progress(dev, smgr->err_state),
+ sec_error(dev, smgr->err_code));
+
+ mutex_unlock(&smgr->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)
{
@@ -329,6 +387,7 @@ 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/fpga-sec-mgr.h b/include/linux/fpga/fpga-sec-mgr.h
index d2e482456d16..ee4230c9830d 100644
--- a/include/linux/fpga/fpga-sec-mgr.h
+++ b/include/linux/fpga/fpga-sec-mgr.h
@@ -110,6 +110,7 @@ struct fpga_sec_mgr {
const u8 *data; /* pointer to update data */
u32 remaining_size; /* size remaining to transfer */
enum fpga_sec_prog progress;
+ enum fpga_sec_prog err_state; /* progress state at time of failure */
enum fpga_sec_err err_code; /* security manager error code */
bool driver_unload;
void *priv;
--
2.25.1