[PATCH v2 9/9] coresight: Fix CTI module refcount leak by making it a helper device

From: James Clark
Date: Fri Mar 10 2023 - 11:35:57 EST

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The CTI module has some hard coded refcounting code that has a leak.
For example running perf and then trying to unload it fails:

perf record -e cs_etm// -a -- ls
rmmod coresight_cti

rmmod: ERROR: Module coresight_cti is in use

The coresight core already handles references of devices in use, so by
making CTI a normal helper device, we get working refcounting for free.

Signed-off-by: James Clark <james.clark@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-core.c | 73 +++----------------
.../hwtracing/coresight/coresight-cti-core.c | 56 +++++++++-----
.../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
drivers/hwtracing/coresight/coresight-cti.h | 4 +-
include/linux/coresight.h | 28 +------
5 files changed, 53 insertions(+), 112 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 3e6ccd9e8d4e..94d84404fb29 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -253,48 +253,6 @@ void coresight_disclaim_device(struct coresight_device *csdev)
}
EXPORT_SYMBOL_GPL(coresight_disclaim_device);

-/* enable or disable an associated CTI device of the supplied CS device */
-static int
-coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
-{
- int ect_ret = 0;
- struct coresight_device *ect_csdev = csdev->ect_dev;
- struct module *mod;
-
- if (!ect_csdev)
- return 0;
- if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
- return 0;
-
- mod = ect_csdev->dev.parent->driver->owner;
- if (enable) {
- if (try_module_get(mod)) {
- ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
- if (ect_ret) {
- module_put(mod);
- } else {
- get_device(ect_csdev->dev.parent);
- csdev->ect_enabled = true;
- }
- } else
- ect_ret = -ENODEV;
- } else {
- if (csdev->ect_enabled) {
- ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
- put_device(ect_csdev->dev.parent);
- module_put(mod);
- csdev->ect_enabled = false;
- }
- }
-
- /* output warning if ECT enable is preventing trace operation */
- if (ect_ret)
- dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
- dev_name(&ect_csdev->dev),
- enable ? "enable" : "disable");
- return ect_ret;
-}
-
/*
* Set the associated ect / cti device while holding the coresight_mutex
* to avoid a race with coresight_enable that may try to use this value.
@@ -302,8 +260,14 @@ coresight_control_assoc_ectdev(struct coresight_device *csdev, bool enable)
void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
struct coresight_device *ect_csdev)
{
+ struct coresight_connection conn = {};
+
mutex_lock(&coresight_mutex);
- csdev->ect_dev = ect_csdev;
+ conn.remote_fwnode = fwnode_handle_get(dev_fwnode(&ect_csdev->dev));
+ conn.remote_dev = ect_csdev;
+ conn.remote_port = conn.port = -1;
+ coresight_add_conn(csdev->dev.parent, csdev->pdata, &conn);
+ coresight_fixup_inputs(csdev);
mutex_unlock(&coresight_mutex);
}
EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
@@ -320,12 +284,8 @@ static int coresight_enable_sink(struct coresight_device *csdev,
if (!sink_ops(csdev)->enable)
return -EINVAL;

- ret = coresight_control_assoc_ectdev(csdev, true);
- if (ret)
- return ret;
ret = sink_ops(csdev)->enable(csdev, mode, data);
if (ret) {
- coresight_control_assoc_ectdev(csdev, false);
return ret;
}
csdev->enable = true;
@@ -343,7 +303,6 @@ static void coresight_disable_sink(struct coresight_device *csdev)
ret = sink_ops(csdev)->disable(csdev);
if (ret)
return;
- coresight_control_assoc_ectdev(csdev, false);
csdev->enable = false;
}

@@ -368,17 +327,11 @@ static int coresight_enable_link(struct coresight_device *csdev,
return outport;

if (link_ops(csdev)->enable) {
- ret = coresight_control_assoc_ectdev(csdev, true);
- if (!ret) {
- ret = link_ops(csdev)->enable(csdev, inport, outport);
- if (ret)
- coresight_control_assoc_ectdev(csdev, false);
- }
+ ret = link_ops(csdev)->enable(csdev, inport, outport);
+ if (!ret)
+ csdev->enable = true;
}

- if (!ret)
- csdev->enable = true;
-
return ret;
}

@@ -407,7 +360,6 @@ static void coresight_disable_link(struct coresight_device *csdev,

if (link_ops(csdev)->disable) {
link_ops(csdev)->disable(csdev, inport, outport);
- coresight_control_assoc_ectdev(csdev, false);
}

for (i = 0; i < nr_conns; i++)
@@ -424,12 +376,8 @@ static int coresight_enable_source(struct coresight_device *csdev,

if (!csdev->enable) {
if (source_ops(csdev)->enable) {
- ret = coresight_control_assoc_ectdev(csdev, true);
- if (ret)
- return ret;
ret = source_ops(csdev)->enable(csdev, NULL, mode);
if (ret) {
- coresight_control_assoc_ectdev(csdev, false);
return ret;
}
}
@@ -482,7 +430,6 @@ static bool coresight_disable_source(struct coresight_device *csdev)
if (atomic_dec_return(csdev->refcnt) == 0) {
if (source_ops(csdev)->disable)
source_ops(csdev)->disable(csdev, NULL);
- coresight_control_assoc_ectdev(csdev, false);
csdev->enable = false;
}
return !csdev->enable;
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index 277c890a1f1f..dbce6680759f 100644
--- a/drivers/hwtracing/coresight/coresight-cti-core.c
+++ b/drivers/hwtracing/coresight/coresight-cti-core.c
@@ -555,7 +555,10 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
mutex_lock(&ect_mutex);

/* exit if current is an ECT device.*/
- if ((csdev->type == CORESIGHT_DEV_TYPE_ECT) || list_empty(&ect_net))
+ if ((csdev->type == CORESIGHT_DEV_TYPE_HELPER &&
+ csdev->subtype.helper_subtype ==
+ CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI) ||
+ list_empty(&ect_net))
goto cti_add_done;

/* if we didn't find the csdev previously we used the fwnode name */
@@ -580,6 +583,22 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
mutex_unlock(&ect_mutex);
}

+static struct coresight_device *cti__get_cti_device(struct coresight_device *csdev)
+{
+ int i;
+ struct coresight_device *tmp;
+
+ for (i = 0; i < csdev->pdata->nr_outconns; i++) {
+ tmp = csdev->pdata->out_conns[i].remote_dev;
+
+ if (tmp && tmp->type == CORESIGHT_DEV_TYPE_HELPER &&
+ tmp->subtype.helper_subtype ==
+ CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI)
+ return tmp;
+ }
+ return NULL;
+}
+
/*
* Removing the associated devices is easier.
* A CTI will not have a value for csdev->ect_dev.
@@ -588,20 +607,21 @@ static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
{
struct cti_drvdata *ctidrv;
struct cti_trig_con *tc;
+ struct coresight_device *cti_csdev = cti__get_cti_device(csdev);
struct cti_device *ctidev;

+ if (!cti_csdev)
+ return;
+
mutex_lock(&ect_mutex);
- if (csdev->ect_dev) {
- ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
- ctidev = &ctidrv->ctidev;
- list_for_each_entry(tc, &ctidev->trig_cons, node) {
- if (tc->con_dev == csdev) {
- cti_remove_sysfs_link(ctidrv, tc);
- tc->con_dev = NULL;
- break;
- }
+ ctidrv = csdev_to_cti_drvdata(cti_csdev);
+ ctidev = &ctidrv->ctidev;
+ list_for_each_entry(tc, &ctidev->trig_cons, node) {
+ if (tc->con_dev == csdev) {
+ cti_remove_sysfs_link(ctidrv, tc);
+ tc->con_dev = NULL;
+ break;
}
- csdev->ect_dev = NULL;
}
mutex_unlock(&ect_mutex);
}
@@ -646,8 +666,6 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata)

list_for_each_entry(tc, &ctidev->trig_cons, node) {
if (tc->con_dev) {
- coresight_set_assoc_ectdev_mutex(tc->con_dev,
- NULL);
cti_remove_sysfs_link(drvdata, tc);
tc->con_dev = NULL;
}
@@ -795,27 +813,27 @@ static void cti_pm_release(struct cti_drvdata *drvdata)
}

/** cti ect operations **/
-int cti_enable(struct coresight_device *csdev)
+int cti_enable(struct coresight_device *csdev, enum cs_mode mode, void *data)
{
struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);

return cti_enable_hw(drvdata);
}

-int cti_disable(struct coresight_device *csdev)
+int cti_disable(struct coresight_device *csdev, void *data)
{
struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);

return cti_disable_hw(drvdata);
}

-static const struct coresight_ops_ect cti_ops_ect = {
+static const struct coresight_ops_helper cti_ops_ect = {
.enable = cti_enable,
.disable = cti_disable,
};

static const struct coresight_ops cti_ops = {
- .ect_ops = &cti_ops_ect,
+ .helper_ops = &cti_ops_ect,
};

/*
@@ -922,8 +940,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)

/* set up coresight component description */
cti_desc.pdata = pdata;
- cti_desc.type = CORESIGHT_DEV_TYPE_ECT;
- cti_desc.subtype.ect_subtype = CORESIGHT_DEV_SUBTYPE_ECT_CTI;
+ cti_desc.type = CORESIGHT_DEV_TYPE_HELPER;
+ cti_desc.subtype.helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI;
cti_desc.ops = &cti_ops;
cti_desc.groups = drvdata->ctidev.con_groups;
cti_desc.dev = dev;
diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
index e528cff9d4e2..d25dd2737b49 100644
--- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
@@ -112,11 +112,11 @@ static ssize_t enable_store(struct device *dev,
ret = pm_runtime_resume_and_get(dev->parent);
if (ret)
return ret;
- ret = cti_enable(drvdata->csdev);
+ ret = cti_enable(drvdata->csdev, CS_MODE_SYSFS, NULL);
if (ret)
pm_runtime_put(dev->parent);
} else {
- ret = cti_disable(drvdata->csdev);
+ ret = cti_disable(drvdata->csdev, NULL);
if (!ret)
pm_runtime_put(dev->parent);
}
diff --git a/drivers/hwtracing/coresight/coresight-cti.h b/drivers/hwtracing/coresight/coresight-cti.h
index 8b106b13a244..cb9ee616d01f 100644
--- a/drivers/hwtracing/coresight/coresight-cti.h
+++ b/drivers/hwtracing/coresight/coresight-cti.h
@@ -215,8 +215,8 @@ int cti_add_connection_entry(struct device *dev, struct cti_drvdata *drvdata,
const char *assoc_dev_name);
struct cti_trig_con *cti_allocate_trig_con(struct device *dev, int in_sigs,
int out_sigs);
-int cti_enable(struct coresight_device *csdev);
-int cti_disable(struct coresight_device *csdev);
+int cti_enable(struct coresight_device *csdev, enum cs_mode mode, void *data);
+int cti_disable(struct coresight_device *csdev, void *data);
void cti_write_all_hw_regs(struct cti_drvdata *drvdata);
void cti_write_intack(struct device *dev, u32 ackval);
void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index c6ee1634d813..cf7a8658ee88 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -40,8 +40,7 @@ enum coresight_dev_type {
CORESIGHT_DEV_TYPE_LINK,
CORESIGHT_DEV_TYPE_LINKSINK,
CORESIGHT_DEV_TYPE_SOURCE,
- CORESIGHT_DEV_TYPE_HELPER,
- CORESIGHT_DEV_TYPE_ECT,
+ CORESIGHT_DEV_TYPE_HELPER
};

enum coresight_dev_subtype_sink {
@@ -66,12 +65,7 @@ enum coresight_dev_subtype_source {

enum coresight_dev_subtype_helper {
CORESIGHT_DEV_SUBTYPE_HELPER_CATU,
-};
-
-/* Embedded Cross Trigger (ECT) sub-types */
-enum coresight_dev_subtype_ect {
- CORESIGHT_DEV_SUBTYPE_ECT_NONE,
- CORESIGHT_DEV_SUBTYPE_ECT_CTI,
+ CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
};

/**
@@ -84,8 +78,6 @@ enum coresight_dev_subtype_ect {
* by @coresight_dev_subtype_source.
* @helper_subtype: type of helper this component is, as defined
* by @coresight_dev_subtype_helper.
- * @ect_subtype: type of cross trigger this component is, as
- * defined by @coresight_dev_subtype_ect
*/
union coresight_dev_subtype {
/* We have some devices which acts as LINK and SINK */
@@ -95,7 +87,6 @@ union coresight_dev_subtype {
};
enum coresight_dev_subtype_source source_subtype;
enum coresight_dev_subtype_helper helper_subtype;
- enum coresight_dev_subtype_ect ect_subtype;
};

/**
@@ -264,12 +255,9 @@ struct coresight_device {
bool activated; /* true only if a sink is part of a path */
struct dev_ext_attribute *ea;
struct coresight_device *def_sink;
- /* cross trigger handling */
- struct coresight_device *ect_dev;
/* sysfs links between components */
int nr_links;
bool has_conns_grp;
- bool ect_enabled; /* true only if associated ect device is enabled */
/* system configuration and feature lists */
struct list_head feature_csdev_list;
struct list_head config_csdev_list;
@@ -377,23 +365,11 @@ struct coresight_ops_helper {
int (*disable)(struct coresight_device *csdev, void *data);
};

-/**
- * struct coresight_ops_ect - Ops for an embedded cross trigger device
- *
- * @enable : Enable the device
- * @disable : Disable the device
- */
-struct coresight_ops_ect {
- int (*enable)(struct coresight_device *csdev);
- int (*disable)(struct coresight_device *csdev);
-};
-
struct coresight_ops {
const struct coresight_ops_sink *sink_ops;
const struct coresight_ops_link *link_ops;
const struct coresight_ops_source *source_ops;
const struct coresight_ops_helper *helper_ops;
- const struct coresight_ops_ect *ect_ops;
};

#if IS_ENABLED(CONFIG_CORESIGHT)
--
2.34.1

Next message: James Clark: "[PATCH v2 7/9] coresight: Refactor out buffer allocation function for ETR"
Previous message: James Clark: "[PATCH v2 8/9] coresight: Enable and disable helper devices adjacent to the path"
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