[PATCH v2 RESEND 1/4] coresight: etm4x: Add lock for reading virtual context ID comparator

[Leo Yan]

Updates to the values and the index are protected via the spinlock.
Ensure we use the same lock to read the value safely.

Signed-off-by: Leo Yan <leo.yan at linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 10ef2a29006e..2f3b4eef8261 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -2111,7 +2111,9 @@ static ssize_t vmid_val_show(struct device *dev,
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
 
+	spin_lock(&drvdata->spinlock);
 	val = (unsigned long)config->vmid_val[config->vmid_idx];
+	spin_unlock(&drvdata->spinlock);
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 
-- 
2.25.1