| Message ID | 20241216115006.415861-8-yeoreum.yun@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: change some driver' spinlock type to raw_spinlock_t | expand |
On Mon, 16 Dec 2024 at 11:50, Yeoreum Yun <yeoreum.yun@arm.com> wrote: > > In coresight-replicator drivers, replicator_drvdata->spinlock can be held > during __schedule() by perf_event_task_sched_out()/in(). > > Since replicator_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 replicator_drvdata->spinlock in > coresight-replicator 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> > --- > drivers/hwtracing/coresight/coresight-replicator.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c > index 0fba87de6d1a..7d36fe2176cc 100644 > --- a/drivers/hwtracing/coresight/coresight-replicator.c > +++ b/drivers/hwtracing/coresight/coresight-replicator.c > @@ -41,7 +41,7 @@ struct replicator_drvdata { > struct clk *atclk; > struct clk *pclk; > struct coresight_device *csdev; > - spinlock_t spinlock; > + raw_spinlock_t spinlock; > bool check_idfilter_val; > }; > > @@ -125,7 +125,7 @@ static int replicator_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 (atomic_read(&out->src_refcnt) == 0) { > if (drvdata->base) > rc = dynamic_replicator_enable(drvdata, in->dest_port, > @@ -135,7 +135,7 @@ static int replicator_enable(struct coresight_device *csdev, > } > if (!rc) > atomic_inc(&out->src_refcnt); > - spin_unlock_irqrestore(&drvdata->spinlock, flags); > + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); > > if (first_enable) > dev_dbg(&csdev->dev, "REPLICATOR enabled\n"); > @@ -179,14 +179,14 @@ static void replicator_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 (atomic_dec_return(&out->src_refcnt) == 0) { > if (drvdata->base) > dynamic_replicator_disable(drvdata, in->dest_port, > out->src_port); > last_disable = true; > } > - spin_unlock_irqrestore(&drvdata->spinlock, flags); > + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); > > if (last_disable) > dev_dbg(&csdev->dev, "REPLICATOR disabled\n"); > @@ -277,7 +277,7 @@ static int replicator_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_SPLIT; > desc.ops = &replicator_cs_ops; > -- > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7} > Reviewed-by: Mike Leach <mike.leach@linaro.org> -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK
diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c index 0fba87de6d1a..7d36fe2176cc 100644 --- a/drivers/hwtracing/coresight/coresight-replicator.c +++ b/drivers/hwtracing/coresight/coresight-replicator.c @@ -41,7 +41,7 @@ struct replicator_drvdata { struct clk *atclk; struct clk *pclk; struct coresight_device *csdev; - spinlock_t spinlock; + raw_spinlock_t spinlock; bool check_idfilter_val; }; @@ -125,7 +125,7 @@ static int replicator_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 (atomic_read(&out->src_refcnt) == 0) { if (drvdata->base) rc = dynamic_replicator_enable(drvdata, in->dest_port, @@ -135,7 +135,7 @@ static int replicator_enable(struct coresight_device *csdev, } if (!rc) atomic_inc(&out->src_refcnt); - spin_unlock_irqrestore(&drvdata->spinlock, flags); + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); if (first_enable) dev_dbg(&csdev->dev, "REPLICATOR enabled\n"); @@ -179,14 +179,14 @@ static void replicator_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 (atomic_dec_return(&out->src_refcnt) == 0) { if (drvdata->base) dynamic_replicator_disable(drvdata, in->dest_port, out->src_port); last_disable = true; } - spin_unlock_irqrestore(&drvdata->spinlock, flags); + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); if (last_disable) dev_dbg(&csdev->dev, "REPLICATOR disabled\n"); @@ -277,7 +277,7 @@ static int replicator_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_SPLIT; desc.ops = &replicator_cs_ops;
In coresight-replicator drivers, replicator_drvdata->spinlock can be held during __schedule() by perf_event_task_sched_out()/in(). Since replicator_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 replicator_drvdata->spinlock in coresight-replicator 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> --- drivers/hwtracing/coresight/coresight-replicator.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)