coresight-cti: change cti_drvdata spinlock's type to raw_spinlock_t

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

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

Reviewed-by: James Clark <[email protected]>
Reviewed-by: Mike Leach <[email protected]>
Signed-off-by: Yeoreum Yun <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: LeviYeoReum

drivers/hwtracing/coresight/coresight-cti-core.c

@@ -93,7 +93,7 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
 	unsigned long flags;
 	int rc = 0;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	/* no need to do anything if enabled or unpowered*/
 	if (config->hw_enabled || !config->hw_powered)
@@ -108,15 +108,15 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
 
 	config->hw_enabled = true;
 	drvdata->config.enable_req_count++;
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 	return rc;
 
 cti_state_unchanged:
 	drvdata->config.enable_req_count++;
 
 	/* cannot enable due to error */
 cti_err_not_enabled:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 	return rc;
 }
 
@@ -125,7 +125,7 @@ static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
 {
 	struct cti_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->hw_powered = true;
 
 	/* no need to do anything if no enable request */
@@ -138,12 +138,12 @@ static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
 
 	cti_write_all_hw_regs(drvdata);
 	config->hw_enabled = true;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return;
 
 	/* did not re-enable due to no claim / no request */
 cti_hp_not_enabled:
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 }
 
 /* disable hardware */
@@ -153,7 +153,7 @@ static int cti_disable_hw(struct cti_drvdata *drvdata)
 	struct coresight_device *csdev = drvdata->csdev;
 	int ret = 0;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/* don't allow negative refcounts, return an error */
 	if (!drvdata->config.enable_req_count) {
@@ -177,12 +177,12 @@ static int cti_disable_hw(struct cti_drvdata *drvdata)
 
 	coresight_disclaim_device_unlocked(csdev);
 	CS_LOCK(drvdata->base);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return ret;
 
 	/* not disabled this call */
 cti_not_disabled:
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return ret;
 }
 
@@ -198,11 +198,11 @@ void cti_write_intack(struct device *dev, u32 ackval)
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct cti_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	/* write if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, CTIINTACK, ackval);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 }
 
 /*
@@ -369,7 +369,7 @@ int cti_channel_trig_op(struct device *dev, enum cti_chan_op op,
 	reg_offset = (direction == CTI_TRIG_IN ? CTIINEN(trigger_idx) :
 		      CTIOUTEN(trigger_idx));
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/* read - modify write - the trigger / channel enable value */
 	reg_value = direction == CTI_TRIG_IN ? config->ctiinen[trigger_idx] :
@@ -388,7 +388,7 @@ int cti_channel_trig_op(struct device *dev, enum cti_chan_op op,
 	/* write through if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, reg_offset, reg_value);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return 0;
 }
 
@@ -406,7 +406,7 @@ int cti_channel_gate_op(struct device *dev, enum cti_chan_gate_op op,
 
 	chan_bitmask = BIT(channel_idx);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	reg_value = config->ctigate;
 	switch (op) {
 	case CTI_GATE_CHAN_ENABLE:
@@ -426,7 +426,7 @@ int cti_channel_gate_op(struct device *dev, enum cti_chan_gate_op op,
 		if (cti_active(config))
 			cti_write_single_reg(drvdata, CTIGATE, reg_value);
 	}
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return err;
 }
 
@@ -445,7 +445,7 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
 
 	chan_bitmask = BIT(channel_idx);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	reg_value = config->ctiappset;
 	switch (op) {
 	case CTI_CHAN_SET:
@@ -473,7 +473,7 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
 
 	if ((err == 0) && cti_active(config))
 		cti_write_single_reg(drvdata, reg_offset, reg_value);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return err;
 }
@@ -676,7 +676,7 @@ static int cti_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
 	if (WARN_ON_ONCE(drvdata->ctidev.cpu != cpu))
 		return NOTIFY_BAD;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	switch (cmd) {
 	case CPU_PM_ENTER:
@@ -716,7 +716,7 @@ static int cti_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
 	}
 
 cti_notify_exit:
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return notify_res;
 }
 
@@ -743,11 +743,11 @@ static int cti_dying_cpu(unsigned int cpu)
 	if (!drvdata)
 		return 0;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	drvdata->config.hw_powered = false;
 	if (drvdata->config.hw_enabled)
 		coresight_disclaim_device(drvdata->csdev);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return 0;
 }
 
@@ -888,7 +888,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
 	drvdata->ctidev.ctm_id = 0;
 	INIT_LIST_HEAD(&drvdata->ctidev.trig_cons);
 
-	spin_lock_init(&drvdata->spinlock);
+	raw_spin_lock_init(&drvdata->spinlock);
 
 	/* initialise CTI driver config values */
 	cti_set_default_config(dev, drvdata);