From: Leo Yan <leo.yan@arm.com>
Date: Thu, 26 Feb 2026 09:23:56 +0000 (+0000)
Subject: coresight: cti: Properly handle negative offsets in cti_reg32_{show|store}()
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9c5ef7a30d9044f8706bd02bfdc4eff7266f3e25;p=thirdparty%2Fkernel%2Flinux.git

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 9ef44956ebdc..4c0a60840efb 100644
--- 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);
 	}