On Tue, Feb 11, 2025 at 10:39:41AM +0000, James Clark wrote:
This can be left behind from a crashed kernel after a kexec so clear it when probing each device. Similarly to coresight_disclaim_device_unlocked(), only clear it if it's already set to avoid races with an external debugger.
We need a csdev_access struct in etm_init_arch_data() so just replace the iomem pointer with a full csdev_access struct. This means all usages need to be updated to go through csa->base.
Signed-off-by: James Clark james.clark@linaro.org
drivers/hwtracing/coresight/coresight-catu.c | 1 + drivers/hwtracing/coresight/coresight-core.c | 48 +++++++++++++++---- .../hwtracing/coresight/coresight-cti-core.c | 2 + drivers/hwtracing/coresight/coresight-etb10.c | 2 + drivers/hwtracing/coresight/coresight-etm.h | 6 +-- .../coresight/coresight-etm3x-core.c | 28 +++++------ .../coresight/coresight-etm3x-sysfs.c | 8 ++-- .../coresight/coresight-etm4x-core.c | 2 + .../hwtracing/coresight/coresight-funnel.c | 2 + .../coresight/coresight-replicator.c | 1 + .../hwtracing/coresight/coresight-tmc-core.c | 1 + include/linux/coresight.h | 3 ++ 12 files changed, 73 insertions(+), 31 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c index d9259c0b6e64..575c2d247a90 100644 --- a/drivers/hwtracing/coresight/coresight-catu.c +++ b/drivers/hwtracing/coresight/coresight-catu.c @@ -558,6 +558,7 @@ static int __catu_probe(struct device *dev, struct resource *res) catu_desc.subtype.helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_CATU; catu_desc.ops = &catu_ops;
coresight_reset_claim(&catu_desc.access); drvdata->csdev = coresight_register(&catu_desc); if (IS_ERR(drvdata->csdev)) ret = PTR_ERR(drvdata->csdev);diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 7fe5d5d432c4..97f33ffad05e 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -212,20 +212,48 @@ int coresight_claim_device(struct coresight_device *csdev) EXPORT_SYMBOL_GPL(coresight_claim_device);
/*
- coresight_disclaim_device_unlocked : Clear the claim tag for the device.
- Clear the claim tag for the device.
- Returns an error if the device wasn't already claimed.
- */
+int coresight_reset_claim(struct csdev_access *csa) +{
int ret;CS_UNLOCK(csa->base);ret = coresight_reset_claim_unlocked(csa);CS_LOCK(csa->base);return ret;+} +EXPORT_SYMBOL_GPL(coresight_reset_claim);
Maybe my question is overlapping with Mike's comment.
Callers never check the return values from coresight_reset_claim(). I am wandering if coresight_reset_claim() can directly call coresight_clear_self_claim_tag() for _trying_ to clear self-host tag in probe phase. Any self claim tag issues will be deferred to detect until enable the component.
For consistent, we might rename coresight_reset_claim() to coresight_reset_self_claim_tag(), which acquires CS lock and clear self claim tag.
+/*
- Clear the claim tag for the device. Called with CS_UNLOCKed for the component.
- Returns an error if the device wasn't already claimed.
- */
+int coresight_reset_claim_unlocked(struct csdev_access *csa) +{
if (coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED) {coresight_clear_self_claim_tag(csa);return 0;}return -EINVAL;+} +EXPORT_SYMBOL_GPL(coresight_reset_claim_unlocked);
+/*
- coresight_disclaim_device_unlocked : Clear the claim tag for the device
*/
- and warn if the device wasn't already claimed.
- Called with CS_UNLOCKed for the component.
void coresight_disclaim_device_unlocked(struct csdev_access *csa) {
if (coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED)coresight_clear_self_claim_tag(csa);else/** The external agent may have not honoured our claim* and has manipulated it. Or something else has seriously* gone wrong in our driver.*/WARN_ON_ONCE(1);
/** Warn if the external agent hasn't honoured our claim* and has manipulated it. Or something else has seriously* gone wrong in our driver.*/WARN_ON_ONCE(coresight_reset_claim_unlocked(csa));} EXPORT_SYMBOL_GPL(coresight_disclaim_device_unlocked);
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c index 073f67a41af9..389a72362f0c 100644 --- a/drivers/hwtracing/coresight/coresight-cti-core.c +++ b/drivers/hwtracing/coresight/coresight-cti-core.c @@ -931,6 +931,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) cti_desc.ops = &cti_ops; cti_desc.groups = drvdata->ctidev.con_groups; cti_desc.dev = dev;
coresight_reset_claim(&cti_desc.access); drvdata->csdev = coresight_register(&cti_desc); if (IS_ERR(drvdata->csdev)) { ret = PTR_ERR(drvdata->csdev);diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index d8bc3e776c88..b598b2c0c9bb 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -772,6 +772,8 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id) desc.pdata = pdata; desc.dev = dev; desc.groups = coresight_etb_groups;
coresight_reset_claim(&desc.access); drvdata->csdev = coresight_register(&desc); if (IS_ERR(drvdata->csdev)) return PTR_ERR(drvdata->csdev);diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h index e02c3ea972c9..a89736309c27 100644 --- a/drivers/hwtracing/coresight/coresight-etm.h +++ b/drivers/hwtracing/coresight/coresight-etm.h @@ -229,7 +229,7 @@ struct etm_config {
- @config: structure holding configuration parameters.
*/ struct etm_drvdata {
void __iomem *base;
struct csdev_access csa;
I would like to extract the change for using `csdev_access` in the ETMv3 driver into a new patch, which is irrelevant to reset self claim tags and would significantly reduce the complexity in this patch.
Thanks, Leo