coresight: cti: Properly handle negative offsets in cti_reg32_{show|store}()

Return an error when the offset is negative.

Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@Arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260226-arm_coresight_cti_refactor_v1-v2-8-b30fada3cfec@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
index 9ef44956ebdc7781717d773fa014165989df2048..4c0a60840efb9ecc47850c1eb5a7abb41b49c5cc 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
@@ -252,8 +252,11 @@ static ssize_t cti_reg32_show(struct device *dev, char *buf,
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_config *config = &drvdata->config;
 
+       if (reg_offset < 0)
+               return -EINVAL;
+
        scoped_guard(raw_spinlock_irqsave, &drvdata->spinlock) {
-               if ((reg_offset >= 0) && cti_is_active(config)) {
+               if (cti_is_active(config)) {
                        val = cti_read_single_reg(drvdata, reg_offset);
                        if (pcached_val)
                                *pcached_val = val;
@@ -280,13 +283,16 @@ static ssize_t cti_reg32_store(struct device *dev, const char *buf,
        if (kstrtoul(buf, 0, &val))
                return -EINVAL;
 
+       if (reg_offset < 0)
+               return -EINVAL;
+
        scoped_guard(raw_spinlock_irqsave, &drvdata->spinlock) {
                /* local store */
                if (pcached_val)
                        *pcached_val = (u32)val;
 
                /* write through if offset and enabled */
-               if ((reg_offset >= 0) && cti_is_active(config))
+               if (cti_is_active(config))
                        cti_write_single_reg(drvdata, reg_offset, val);
        }