coresight-tmc: change tmc_drvdata spinlock's type to raw_spinlock_t

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

Since tmc_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 tmc_drvdata->spinlock in coresight-tmc 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/20250306121110.1647948-9-yeoreum.yun@arm.com

Author: LeviYeoReum

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

@@ -358,12 +358,12 @@ static int tmc_crashdata_open(struct inode *inode, struct file *file)
 	mdata = drvdata->crash_mdata.vaddr;
 	rbuf = &drvdata->resrv_buf;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (mdata->valid)
 		rbuf->reading = true;
 	else
 		err = -ENOENT;
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 	if (err)
 		goto exit;
 
@@ -408,9 +408,9 @@ static int tmc_crashdata_release(struct inode *inode, struct file *file)
 						   crashdev);
 
 	rbuf = &drvdata->resrv_buf;
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	rbuf->reading = false;
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	dev_dbg(&drvdata->csdev->dev, "%s: released\n", __func__);
 	return ret;
@@ -801,7 +801,7 @@ static int __tmc_probe(struct device *dev, struct resource *res)
 	drvdata->base = base;
 	desc.access = CSDEV_ACCESS_IOMEM(base);
 
-	spin_lock_init(&drvdata->spinlock);
+	raw_spin_lock_init(&drvdata->spinlock);
 
 	devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
 	drvdata->config_type = BMVAL(devid, 6, 7);
@@ -913,7 +913,7 @@ static void tmc_shutdown(struct amba_device *adev)
 	unsigned long flags;
 	struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	if (coresight_get_mode(drvdata->csdev) == CS_MODE_DISABLED)
 		goto out;
@@ -927,7 +927,7 @@ static void tmc_shutdown(struct amba_device *adev)
 	 * the system is going down after this.
 	 */
 out:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 }
 
 static void __tmc_remove(struct device *dev)

drivers/hwtracing/coresight/coresight-tmc-etf.c

@@ -185,17 +185,17 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
 	 * If we don't have a buffer release the lock and allocate memory.
 	 * Otherwise keep the lock and move along.
 	 */
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (!drvdata->buf) {
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 		/* Allocating the memory here while outside of the spinlock */
 		buf = kzalloc(drvdata->size, GFP_KERNEL);
 		if (!buf)
 			return -ENOMEM;
 
 		/* Let's try again */
-		spin_lock_irqsave(&drvdata->spinlock, flags);
+		raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	}
 
 	if (drvdata->reading) {
@@ -237,7 +237,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
 		used = false;
 	}
 out:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	/* Free memory outside the spinlock if need be */
 	if (!used)
@@ -255,7 +255,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
 	struct perf_output_handle *handle = data;
 	struct cs_buffers *buf = etm_perf_sink_config(handle);
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	do {
 		ret = -EINVAL;
 		if (drvdata->reading)
@@ -298,7 +298,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
 			csdev->refcnt++;
 		}
 	} while (0);
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	return ret;
 }
@@ -333,16 +333,16 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
 	unsigned long flags;
 	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	if (drvdata->reading) {
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		return -EBUSY;
 	}
 
 	csdev->refcnt--;
 	if (csdev->refcnt) {
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		return -EBUSY;
 	}
 
@@ -353,7 +353,7 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
 	drvdata->pid = -1;
 	coresight_set_mode(csdev, CS_MODE_DISABLED);
 
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	dev_dbg(&csdev->dev, "TMC-ETB/ETF disabled\n");
 	return 0;
@@ -368,9 +368,9 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
 	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	bool first_enable = false;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (drvdata->reading) {
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		return -EBUSY;
 	}
 
@@ -383,7 +383,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
 	}
 	if (!ret)
 		csdev->refcnt++;
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	if (first_enable)
 		dev_dbg(&csdev->dev, "TMC-ETF enabled\n");
@@ -398,9 +398,9 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
 	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	bool last_disable = false;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	if (drvdata->reading) {
-		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		return;
 	}
 
@@ -410,7 +410,7 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
 		coresight_set_mode(csdev, CS_MODE_DISABLED);
 		last_disable = true;
 	}
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	if (last_disable)
 		dev_dbg(&csdev->dev, "TMC-ETF disabled\n");
@@ -490,7 +490,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
 	if (WARN_ON_ONCE(coresight_get_mode(csdev) != CS_MODE_PERF))
 		return 0;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	/* Don't do anything if another tracer is using this sink */
 	if (csdev->refcnt != 1)
@@ -587,7 +587,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
 	 */
 	CS_LOCK(drvdata->base);
 out:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	return to_read;
 }
@@ -705,7 +705,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
 			 drvdata->config_type != TMC_CONFIG_TYPE_ETF))
 		return -EINVAL;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	if (drvdata->reading) {
 		ret = -EBUSY;
@@ -737,7 +737,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
 
 	drvdata->reading = true;
 out:
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	return ret;
 }
@@ -754,14 +754,14 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 			 drvdata->config_type != TMC_CONFIG_TYPE_ETF))
 		return -EINVAL;
 
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	/* Re-enable the TMC if need be */
 	if (coresight_get_mode(drvdata->csdev) == CS_MODE_SYSFS) {
 		/* There is no point in reading a TMC in HW FIFO mode */
 		mode = readl_relaxed(drvdata->base + TMC_MODE);
 		if (mode != TMC_MODE_CIRCULAR_BUFFER) {
-			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 			return -EINVAL;
 		}
 		/*
@@ -775,7 +775,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 		memset(drvdata->buf, 0, drvdata->size);
 		rc = __tmc_etb_enable_hw(drvdata);
 		if (rc) {
-			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 			return rc;
 		}
 	} else {
@@ -788,7 +788,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 	}
 
 	drvdata->reading = false;
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	/*
 	 * Free allocated memory outside of the spinlock.  There is no need