The sysfs files that change the operational parameters for TMC buffer_size, stop_on_flush and trigger_cntr are writable when the TMC is in use.

The new values will have no effect and be silently ignored.

Alter the sysfs functions to return -EBUSY if the TMC is currently in use, and also protect the write values using the spinlock.

Signed-off-by: Mike Leach mike.leach@linaro.org --- .../hwtracing/coresight/coresight-tmc-core.c | 41 ++++++++++++++++--- 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 36599c431be6..a1216a1f9681 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -489,15 +489,24 @@ static ssize_t trigger_cntr_store(struct device *dev, const char *buf, size_t size) { int ret; - unsigned long val; + unsigned long val, flags; struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);

ret = kstrtoul(buf, 16, &val); if (ret) return ret;

+ /* do not permit write if the sink is currently in use */ + raw_spin_lock_irqsave(&drvdata->spinlock, flags); + if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) { + ret = -EBUSY; + goto out; + } drvdata->trigger_cntr = val; - return size; + ret = size; +out: + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); + return ret; } static DEVICE_ATTR_RW(trigger_cntr);

@@ -514,7 +523,7 @@ static ssize_t buffer_size_store(struct device *dev, const char *buf, size_t size) { int ret; - unsigned long val; + unsigned long val, flags; struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);

/* Only permitted for TMC-ETRs */ @@ -527,8 +536,18 @@ static ssize_t buffer_size_store(struct device *dev, /* The buffer size should be page aligned */ if (val & (PAGE_SIZE - 1)) return -EINVAL; + + /* do not permit write if the sink is currently in use */ + raw_spin_lock_irqsave(&drvdata->spinlock, flags); + if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) { + ret = -EBUSY; + goto out; + } drvdata->size = val; - return size; + ret = size; +out: + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); + return ret; }

static DEVICE_ATTR_RW(buffer_size); @@ -547,17 +566,27 @@ static ssize_t stop_on_flush_store(struct device *dev, { int ret; u8 val; + unsigned long flags; struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);

ret = kstrtou8(buf, 0, &val); if (ret) return ret; + + /* do not permit write if the sink is currently in use */ + raw_spin_lock_irqsave(&drvdata->spinlock, flags); + if (coresight_get_mode(drvdata->csdev) != CS_MODE_DISABLED) { + ret = -EBUSY; + goto out; + } if (val) drvdata->stop_on_flush = true; else drvdata->stop_on_flush = false; - - return size; + ret = size; +out: + raw_spin_unlock_irqrestore(&drvdata->spinlock, flags); + return ret; }

static DEVICE_ATTR_RW(stop_on_flush);