[SRU][P:linux, N:linux-azure-nvidia-6.14][PATCH v2 3/3] coresight: change coresight_device lock type to raw_spinlock_t

[John Cabaj]

From: Yeoreum Yun <yeoreum.yun at arm.com>

BugLink: https://bugs.launchpad.net/bugs/2122527

coresight_device->cscfg_csdev_lock can be held during __schedule()
by perf_event_task_sched_out()/in().

Since coresight->cscfg_csdev_lock type is spinlock_t and
perf_event_task_sched_out()/in() is called after acquiring rq_lock,
which is raw_spinlock_t (an unsleepable lock),
this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.

To address this, change type of coresight_device->cscfg_csdev_lock
from spinlock_t to raw_spinlock_t.

Reviewed-by: James Clark <james.clark at linaro.org>
Reviewed-by: Mike Leach <mike.leach at linaro.org>
Signed-off-by: Yeoreum Yun <yeoreum.yun at arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
Link: https://lore.kernel.org/r/20250306121110.1647948-2-yeoreum.yun@arm.com
(cherry picked from commit 26f060c106f630e34876c096c1c8997a9e68c371)
Signed-off-by: John Cabaj <john.cabaj at canonical.com>
---
 .../hwtracing/coresight/coresight-syscfg.c    | 26 +++++++++----------
 include/linux/coresight.h                     |  2 +-
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index aa3d3b12652b..83dad24e0116 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -89,9 +89,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
 	}
 	/* if matched features, add config to device.*/
 	if (config_csdev) {
-		spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+		raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 		list_add(&config_csdev->node, &csdev->config_csdev_list);
-		spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+		raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 	}
 
 	return 0;
@@ -194,9 +194,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
 
 	/* add to internal csdev feature list & initialise using reset call */
 	cscfg_reset_feat(feat_csdev);
-	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 	list_add(&feat_csdev->node, &csdev->feature_csdev_list);
-	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 
 	return 0;
 }
@@ -767,7 +767,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev,
 
 	INIT_LIST_HEAD(&csdev->feature_csdev_list);
 	INIT_LIST_HEAD(&csdev->config_csdev_list);
-	spin_lock_init(&csdev->cscfg_csdev_lock);
+	raw_spin_lock_init(&csdev->cscfg_csdev_lock);
 
 	return 0;
 }
@@ -857,7 +857,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
 	struct cscfg_feature_csdev *feat_csdev;
 	unsigned long flags;
 
-	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 	if (list_empty(&csdev->feature_csdev_list))
 		goto unlock_exit;
 
@@ -865,7 +865,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
 		cscfg_reset_feat(feat_csdev);
 
 unlock_exit:
-	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 }
 EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
 
@@ -1074,7 +1074,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 	 * Look for matching configuration - set the active configuration
 	 * context if found.
 	 */
-	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 	list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
 		config_desc = config_csdev_item->config_desc;
 		if (((unsigned long)config_desc->event_ea->var == cfg_hash) &&
@@ -1084,7 +1084,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 			break;
 		}
 	}
-	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 
 	/*
 	 * If found, attempt to enable
@@ -1105,12 +1105,12 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 			 *
 			 * Set enabled if OK, err if not.
 			 */
-			spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+			raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 			if (csdev->active_cscfg_ctxt)
 				config_csdev_active->enabled = true;
 			else
 				err = -EBUSY;
-			spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+			raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 		}
 
 		if (err)
@@ -1143,7 +1143,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
 	 * If it was not enabled, we have no work to do, otherwise mark as disabled.
 	 * Clear the active config pointer.
 	 */
-	spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
 	config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
 	if (config_csdev) {
 		if (!config_csdev->enabled)
@@ -1152,7 +1152,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
 			config_csdev->enabled = false;
 	}
 	csdev->active_cscfg_ctxt = NULL;
-	spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+	raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
 
 	/* true if there was an enabled active config */
 	if (config_csdev) {
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 9e79cce58db7..3bcfdc456176 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -301,7 +301,7 @@ struct coresight_device {
 	/* system configuration and feature lists */
 	struct list_head feature_csdev_list;
 	struct list_head config_csdev_list;
-	spinlock_t cscfg_csdev_lock;
+	raw_spinlock_t cscfg_csdev_lock;
 	void *active_cscfg_ctxt;
 };
 
-- 
2.43.0