[PATCH v2 1/4] coresight: syscfg: Fail to enable a configuration not loaded on the device

[Amir Ayupov]

cscfg_csdev_enable_active_config() looks up the selected configuration in
the device's loaded configurations, and returns success when it is not
there. A configuration is only loaded on devices that match at least one
of its features, so a perf session or sysfs enable that selects it on any
other device runs without the configuration, with no error.

Return -EINVAL instead, so enabling the source fails on that device. The
function is only called with a non-zero configuration hash, so sources
enabled without a configuration are unaffected.

Fixes: f8cce2ff3c04 ("coresight: syscfg: Add API to activate and enable configurations")
Assisted-by: Devmate:Opus-5.5
Signed-off-by: Amir Ayupov <aaupov at fb.com>
---
 .../hwtracing/coresight/coresight-syscfg.c    | 53 ++++++++++---------
 1 file changed, 28 insertions(+), 25 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 2bfdd7b45e49c..a816c22c87bc8 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -1088,36 +1088,39 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 	raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 
 	/*
-	 * If found, attempt to enable
+	 * The configuration is active but not loaded on this device, because
+	 * none of its features match the device. Fail rather than trace
+	 * without it.
 	 */
-	if (config_csdev_active) {
+	if (!config_csdev_active)
+		return -EINVAL;
+
+	/*
+	 * Call the generic routine that will program up the internal
+	 * driver structures prior to programming up the hardware.
+	 * This routine takes the driver spinlock saved in the configs.
+	 */
+	err = cscfg_csdev_enable_config(config_csdev_active, preset);
+	if (!err) {
 		/*
-		 * Call the generic routine that will program up the internal
-		 * driver structures prior to programming up the hardware.
-		 * This routine takes the driver spinlock saved in the configs.
+		 * Successful programming. Check the active_cscfg_ctxt
+		 * pointer to ensure no pre-emption disabled it via
+		 * cscfg_csdev_disable_active_config() before
+		 * we could start.
+		 *
+		 * Set enabled if OK, err if not.
 		 */
-		err = cscfg_csdev_enable_config(config_csdev_active, preset);
-		if (!err) {
-			/*
-			 * Successful programming. Check the active_cscfg_ctxt
-			 * pointer to ensure no pre-emption disabled it via
-			 * cscfg_csdev_disable_active_config() before
-			 * we could start.
-			 *
-			 * Set enabled if OK, err if not.
-			 */
-			raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
-			if (csdev->active_cscfg_ctxt)
-				config_csdev_active->enabled = true;
-			else
-				err = -EBUSY;
-			raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
-		}
-
-		if (err)
-			cscfg_config_desc_put(config_desc);
+		raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+		if (csdev->active_cscfg_ctxt)
+			config_csdev_active->enabled = true;
+		else
+			err = -EBUSY;
+		raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 	}
 
+	if (err)
+		cscfg_config_desc_put(config_desc);
+
 	return err;
 }
 EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
-- 
2.52.0