On 01/12/2025 9:52 am, Kuan-Wei Chiu wrote:
The cntr_val_show() function was intended to print the values of all counters using a loop. However, due to a buffer overwrite issue with sprintf(), it effectively only displayed the value of the last counter.
The companion function, cntr_val_store(), allows users to modify a specific counter selected by 'cntr_idx'. To maintain consistency between read and write operations and to align with the ETM4x driver behavior, modify cntr_val_show() to report only the value of the currently selected counter.
This change removes the loop and the "counter %d:" prefix, printing only the hexadecimal value. It also adopts sysfs_emit() for standard sysfs output formatting.
Fixes: a939fc5a71ad ("coresight-etm: add CoreSight ETM/PTM driver") Signed-off-by: Kuan-Wei Chiu visitorckw@gmail.com
Build test only.
Changes in v2:
- Redesigned the fix to match cntr_val_store() logic (display only the currently selected counter) instead of attempting to list all counters.
- Removed the loop and the "counter %d:" prefix.
- Switched from sprintf() to sysfs_emit().
- Refactored control flow to use a single return point.
v1: https://lore.kernel.org/lkml/20251121002350.1166758-1-visitorckw@gmail.com/
.../hwtracing/coresight/coresight-etm3x-sysfs.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c index 762109307b86..a6a650331196 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c @@ -717,26 +717,19 @@ static DEVICE_ATTR_RW(cntr_rld_event); static ssize_t cntr_val_show(struct device *dev, struct device_attribute *attr, char *buf) {
- int i, ret = 0; u32 val; struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_config *config = &drvdata->config;
if (!coresight_get_mode(drvdata->csdev)) { spin_lock(&drvdata->spinlock);
for (i = 0; i < drvdata->nr_cntr; i++)ret += sprintf(buf, "counter %d: %x\n",i, config->cntr_val[i]);
val = config->cntr_val[config->cntr_idx];
return ret;- }
- for (i = 0; i < drvdata->nr_cntr; i++) {
val = etm_readl(drvdata, ETMCNTVRn(i));ret += sprintf(buf, "counter %d: %x\n", i, val);
- } else {
val = etm_readl(drvdata, ETMCNTVRn(config->cntr_idx));
- return ret;
- return sysfs_emit(buf, "%x\n", val);
Sorry I missed this on the previous version, but this should be %#x to add the "0x" prefix. All the other ones in this file have it. Otherwise you can't tell the difference between decimal and hex.
} static ssize_t cntr_val_store(struct device *dev,