CoreSight December 2025

coresight@lists.linaro.org

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41 discussions

Re: [PATCH v2] coresight: etm3x: Fix cntr_val_show() to match cntr_val_store() behavior

by James Clark

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(a)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]; > spin_unlock(&drvdata->spinlock); > - 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,

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CoreSight December 2025