diff options
| author | James Clark <james.clark@arm.com> | 2023-01-10 11:07:34 +0000 |
|---|---|---|
| committer | Suzuki K Poulose <suzuki.poulose@arm.com> | 2023-01-16 10:10:18 +0000 |
| commit | 3244fb6dbbf1ffc114cdf382cc167bdd8c18088a (patch) | |
| tree | 7ed5d64d3b98b189e0e1060c05b9eb35fefb820b /drivers/hwtracing | |
| parent | 589d928248b72f8377d45904a14bcf686aa8bbeb (diff) | |
| download | lwn-3244fb6dbbf1ffc114cdf382cc167bdd8c18088a.tar.gz lwn-3244fb6dbbf1ffc114cdf382cc167bdd8c18088a.zip | |
coresight: cti: Prevent negative values of enable count
Writing 0 to the enable control repeatedly results in a negative value
for enable_req_count. After this, writing 1 to the enable control
appears to not work until the count returns to positive.
Change it so that it's impossible for enable_req_count to be < 0.
Return an error to indicate that the disable request was invalid.
Fixes: 835d722ba10a ("coresight: cti: Initial CoreSight CTI Driver")
Tested-by: Jinlong Mao <quic_jinlmao@quicinc.com>
Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230110110736.2709917-2-james.clark@arm.com
Diffstat (limited to 'drivers/hwtracing')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-cti-core.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c index d2cf4f4848e1..838872f2484d 100644 --- a/drivers/hwtracing/coresight/coresight-cti-core.c +++ b/drivers/hwtracing/coresight/coresight-cti-core.c @@ -151,9 +151,16 @@ static int cti_disable_hw(struct cti_drvdata *drvdata) { struct cti_config *config = &drvdata->config; struct coresight_device *csdev = drvdata->csdev; + int ret = 0; spin_lock(&drvdata->spinlock); + /* don't allow negative refcounts, return an error */ + if (!atomic_read(&drvdata->config.enable_req_count)) { + ret = -EINVAL; + goto cti_not_disabled; + } + /* check refcount - disable on 0 */ if (atomic_dec_return(&drvdata->config.enable_req_count) > 0) goto cti_not_disabled; @@ -171,12 +178,12 @@ static int cti_disable_hw(struct cti_drvdata *drvdata) coresight_disclaim_device_unlocked(csdev); CS_LOCK(drvdata->base); spin_unlock(&drvdata->spinlock); - return 0; + return ret; /* not disabled this call */ cti_not_disabled: spin_unlock(&drvdata->spinlock); - return 0; + return ret; } void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value) |