coresight-funnel: change funnel_drvdata spinlock's type to raw_spinlock_t

In coresight-funnel drivers, cti_drvdata->spinlock can be held
during __schedule() by perf_event_task_sched_out()/in().

Since funnel_drvdata->spinlock 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 funnel_drvdata->spinlock in
coresight-funnel drivers, which can be called by
perf_event_task_sched_out()/in(), from spinlock_t to raw_spinlock_t.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250306121110.1647948-7-yeoreum.yun@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
index 8faf51469bb8ce6cc1b739d62fd5b3fc8484659a..0541712b2bcb69e0c08bfcf8cddc940d46edf044 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-funnel.c
+++ b/drivers/hwtracing/coresight/coresight-funnel.c
@@ -47,7 +47,7 @@ struct funnel_drvdata {
        struct clk              *pclk;
        struct coresight_device *csdev;
        unsigned long           priority;
-       spinlock_t              spinlock;
+       raw_spinlock_t          spinlock;
 };
 
 static int dynamic_funnel_enable_hw(struct funnel_drvdata *drvdata, int port)
@@ -85,7 +85,7 @@ static int funnel_enable(struct coresight_device *csdev,
        unsigned long flags;
        bool first_enable = false;
 
-       spin_lock_irqsave(&drvdata->spinlock, flags);
+       raw_spin_lock_irqsave(&drvdata->spinlock, flags);
        if (in->dest_refcnt == 0) {
                if (drvdata->base)
                        rc = dynamic_funnel_enable_hw(drvdata, in->dest_port);
@@ -94,7 +94,7 @@ static int funnel_enable(struct coresight_device *csdev,
        }
        if (!rc)
                in->dest_refcnt++;
-       spin_unlock_irqrestore(&drvdata->spinlock, flags);
+       raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
        if (first_enable)
                dev_dbg(&csdev->dev, "FUNNEL inport %d enabled\n",
@@ -129,13 +129,13 @@ static void funnel_disable(struct coresight_device *csdev,
        unsigned long flags;
        bool last_disable = false;
 
-       spin_lock_irqsave(&drvdata->spinlock, flags);
+       raw_spin_lock_irqsave(&drvdata->spinlock, flags);
        if (--in->dest_refcnt == 0) {
                if (drvdata->base)
                        dynamic_funnel_disable_hw(drvdata, in->dest_port);
                last_disable = true;
        }
-       spin_unlock_irqrestore(&drvdata->spinlock, flags);
+       raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
        if (last_disable)
                dev_dbg(&csdev->dev, "FUNNEL inport %d disabled\n",
@@ -266,7 +266,7 @@ static int funnel_probe(struct device *dev, struct resource *res)
        }
        dev->platform_data = pdata;
 
-       spin_lock_init(&drvdata->spinlock);
+       raw_spin_lock_init(&drvdata->spinlock);
        desc.type = CORESIGHT_DEV_TYPE_LINK;
        desc.subtype.link_subtype = CORESIGHT_DEV_SUBTYPE_LINK_MERG;
        desc.ops = &funnel_cs_ops;