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 <james.clark@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250306121110.1647948-5-yeoreum.yun@arm.com

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)
@@ -108,7 +108,7 @@ 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:
@@ -116,7 +116,7 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
 
 	/* 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);

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

@@ -84,11 +84,11 @@ static ssize_t enable_show(struct device *dev,
 	bool enabled, powered;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	enable_req = drvdata->config.enable_req_count;
 	powered = drvdata->config.hw_powered;
 	enabled = drvdata->config.hw_enabled;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	if (powered)
 		return sprintf(buf, "%d\n", enabled);
@@ -134,9 +134,9 @@ static ssize_t powered_show(struct device *dev,
 	bool powered;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	powered = drvdata->config.hw_powered;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%d\n", powered);
 }
@@ -181,10 +181,10 @@ static ssize_t coresight_cti_reg_show(struct device *dev,
 	u32 val = 0;
 
 	pm_runtime_get_sync(dev->parent);
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	if (drvdata->config.hw_powered)
 		val = readl_relaxed(drvdata->base + cti_attr->off);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	pm_runtime_put_sync(dev->parent);
 	return sysfs_emit(buf, "0x%x\n", val);
 }
@@ -202,10 +202,10 @@ static __maybe_unused ssize_t coresight_cti_reg_store(struct device *dev,
 		return -EINVAL;
 
 	pm_runtime_get_sync(dev->parent);
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	if (drvdata->config.hw_powered)
 		cti_write_single_reg(drvdata, cti_attr->off, val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	pm_runtime_put_sync(dev->parent);
 	return size;
 }
@@ -264,7 +264,7 @@ static ssize_t cti_reg32_show(struct device *dev, char *buf,
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct cti_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	if ((reg_offset >= 0) && cti_active(config)) {
 		CS_UNLOCK(drvdata->base);
 		val = readl_relaxed(drvdata->base + reg_offset);
@@ -274,7 +274,7 @@ static ssize_t cti_reg32_show(struct device *dev, char *buf,
 	} else if (pcached_val) {
 		val = *pcached_val;
 	}
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return sprintf(buf, "%#x\n", val);
 }
 
@@ -293,7 +293,7 @@ static ssize_t cti_reg32_store(struct device *dev, const char *buf,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	/* local store */
 	if (pcached_val)
 		*pcached_val = (u32)val;
@@ -301,7 +301,7 @@ static ssize_t cti_reg32_store(struct device *dev, const char *buf,
 	/* write through if offset and enabled */
 	if ((reg_offset >= 0) && cti_active(config))
 		cti_write_single_reg(drvdata, reg_offset, val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 
@@ -349,9 +349,9 @@ static ssize_t inout_sel_store(struct device *dev,
 	if (val > (CTIINOUTEN_MAX - 1))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	drvdata->config.ctiinout_sel = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_RW(inout_sel);
@@ -364,10 +364,10 @@ static ssize_t inen_show(struct device *dev,
 	int index;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	index = drvdata->config.ctiinout_sel;
 	val = drvdata->config.ctiinen[index];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return sprintf(buf, "%#lx\n", val);
 }
 
@@ -383,14 +383,14 @@ static ssize_t inen_store(struct device *dev,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	index = config->ctiinout_sel;
 	config->ctiinen[index] = val;
 
 	/* write through if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, CTIINEN(index), val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_RW(inen);
@@ -403,10 +403,10 @@ static ssize_t outen_show(struct device *dev,
 	int index;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	index = drvdata->config.ctiinout_sel;
 	val = drvdata->config.ctiouten[index];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return sprintf(buf, "%#lx\n", val);
 }
 
@@ -422,14 +422,14 @@ static ssize_t outen_store(struct device *dev,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	index = config->ctiinout_sel;
 	config->ctiouten[index] = val;
 
 	/* write through if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, CTIOUTEN(index), val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_RW(outen);
@@ -463,7 +463,7 @@ static ssize_t appclear_store(struct device *dev,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/* a 1'b1 in appclr clears down the same bit in appset*/
 	config->ctiappset &= ~val;
@@ -471,7 +471,7 @@ static ssize_t appclear_store(struct device *dev,
 	/* write through if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, CTIAPPCLEAR, val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_WO(appclear);
@@ -487,12 +487,12 @@ static ssize_t apppulse_store(struct device *dev,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/* write through if enabled */
 	if (cti_active(config))
 		cti_write_single_reg(drvdata, CTIAPPPULSE, val);
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_WO(apppulse);
@@ -681,9 +681,9 @@ static ssize_t trig_filter_enable_show(struct device *dev,
 	u32 val;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = drvdata->config.trig_filter_enable;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return sprintf(buf, "%d\n", val);
 }
 
@@ -697,9 +697,9 @@ static ssize_t trig_filter_enable_store(struct device *dev,
 	if (kstrtoul(buf, 0, &val))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	drvdata->config.trig_filter_enable = !!val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_RW(trig_filter_enable);
@@ -728,7 +728,7 @@ static ssize_t chan_xtrigs_reset_store(struct device *dev,
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct cti_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/* clear the CTI trigger / channel programming registers */
 	for (i = 0; i < config->nr_trig_max; i++) {
@@ -747,7 +747,7 @@ static ssize_t chan_xtrigs_reset_store(struct device *dev,
 	if (cti_active(config))
 		cti_write_all_hw_regs(drvdata);
 
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 static DEVICE_ATTR_WO(chan_xtrigs_reset);
@@ -768,9 +768,9 @@ static ssize_t chan_xtrigs_sel_store(struct device *dev,
 	if (val > (drvdata->config.nr_ctm_channels - 1))
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	drvdata->config.xtrig_rchan_sel = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
 
@@ -781,9 +781,9 @@ static ssize_t chan_xtrigs_sel_show(struct device *dev,
 	unsigned long val;
 	struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = drvdata->config.xtrig_rchan_sel;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%ld\n", val);
 }
@@ -838,12 +838,12 @@ static ssize_t print_chan_list(struct device *dev,
 	unsigned long inuse_bits = 0, chan_mask;
 
 	/* scan regs to get bitmap of channels in use. */
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	for (i = 0; i < config->nr_trig_max; i++) {
 		inuse_bits |= config->ctiinen[i];
 		inuse_bits |= config->ctiouten[i];
 	}
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	/* inverse bits if printing free channels */
 	if (!inuse)

drivers/hwtracing/coresight/coresight-cti.h

@@ -175,7 +175,7 @@ struct cti_drvdata {
 	void __iomem *base;
 	struct coresight_device	*csdev;
 	struct cti_device ctidev;
-	spinlock_t spinlock;
+	raw_spinlock_t spinlock;
 	struct cti_config config;
 	struct list_head node;
 	void (*csdev_release)(struct device *dev);