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@arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 99 ++++++-------------
.../hwtracing/coresight/coresight-cti-core.c | 52 +++++-----
.../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
drivers/hwtracing/coresight/coresight-cti.h | 4 +-
drivers/hwtracing/coresight/coresight-priv.h | 4 +-
drivers/hwtracing/coresight/coresight-sysfs.c | 4 +
include/linux/coresight.h | 30 +-----
7 files changed, 70 insertions(+), 127 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 65f5bd8516d8..458d91b4e23f 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -254,60 +254,39 @@ 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
+ * Add a helper as an output device while holding the coresight_mutex
* to avoid a race with coresight_enable that may try to use this value.
*/
-void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
- struct coresight_device *ect_csdev)
+void coresight_add_helper_mutex(struct coresight_device *csdev,
+ struct coresight_device *helper)
{
+ int i;
+ struct coresight_connection conn = {};
+
mutex_lock(&coresight_mutex);
- csdev->ect_dev = ect_csdev;
+ conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
+ conn.dest_dev = helper;
+ conn.dest_port = conn.src_port = -1;
+ conn.src_dev = csdev;
+
+ /*
+ * Check for duplicates because this is called every time a helper
+ * device is re-loaded. Existing connections will get re-linked
+ * automatically.
+ */
+ for (i = 0; i < csdev->pdata->nr_outconns; ++i)
+ if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
+ goto unlock;
+
+ coresight_add_out_conn(csdev->dev.parent, csdev->pdata, &conn);
+ coresight_add_in_conn(
+ csdev->pdata->out_conns[csdev->pdata->nr_outconns - 1]);
+
+unlock:
mutex_unlock(&coresight_mutex);
}
-EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
+EXPORT_SYMBOL_GPL(coresight_add_helper_mutex);
static int coresight_enable_sink(struct coresight_device *csdev,
enum cs_mode mode, void *data)
@@ -321,12 +300,8 @@ 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;
@@ -344,7 +319,6 @@ 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;
}
@@ -369,17 +343,11 @@ static int coresight_enable_link(struct coresight_device *csdev,
return PTR_ERR(outconn);
if (link_ops(csdev)->enable) {
- ret = coresight_control_assoc_ectdev(csdev, true);
- if (!ret) {
- ret = link_ops(csdev)->enable(csdev, inconn, outconn);
- if (ret)
- coresight_control_assoc_ectdev(csdev, false);
- }
+ ret = link_ops(csdev)->enable(csdev, inconn, outconn);
+ if (!ret)
+ csdev->enable = true;
}
- if (!ret)
- csdev->enable = true;
-
return ret;
}
@@ -400,7 +368,6 @@ static void coresight_disable_link(struct coresight_device *csdev,
if (link_ops(csdev)->disable) {
link_ops(csdev)->disable(csdev, inconn, outconn);
- coresight_control_assoc_ectdev(csdev, false);
}
if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
@@ -428,14 +395,9 @@ int coresight_enable_source(struct coresight_device *csdev, void *data,
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, data, mode);
- if (ret) {
- coresight_control_assoc_ectdev(csdev, false);
+ if (ret)
return ret;
- }
}
csdev->enable = true;
}
@@ -499,7 +461,6 @@ bool coresight_disable_source(struct coresight_device *csdev, void *data)
if (atomic_dec_return(&csdev->refcnt) == 0) {
if (source_ops(csdev)->disable)
source_ops(csdev)->disable(csdev, data);
- coresight_control_assoc_ectdev(csdev, false);
coresight_disable_helpers(csdev);
csdev->enable = false;
}
diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
index 277c890a1f1f..db7a2212ec18 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 */
@@ -571,8 +574,7 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
* if we found a matching csdev then update the ECT
* association pointer for the device with this CTI.
*/
- coresight_set_assoc_ectdev_mutex(csdev,
- ect_item->csdev);
+ coresight_add_helper_mutex(csdev, ect_item->csdev);
break;
}
}
@@ -582,26 +584,30 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
/*
* Removing the associated devices is easier.
- * A CTI will not have a value for csdev->ect_dev.
*/
static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
{
struct cti_drvdata *ctidrv;
struct cti_trig_con *tc;
+ union coresight_dev_subtype cti_subtype = {
+ .helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
+ };
+ struct coresight_device *cti_csdev = coresight_find_output_type(
+ csdev->pdata, CORESIGHT_DEV_TYPE_HELPER, cti_subtype);
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);
}
@@ -630,8 +636,8 @@ static void cti_update_conn_xrefs(struct cti_drvdata *drvdata)
/* if we can set the sysfs link */
if (cti_add_sysfs_link(drvdata, tc))
/* set the CTI/csdev association */
- coresight_set_assoc_ectdev_mutex(tc->con_dev,
- drvdata->csdev);
+ coresight_add_helper_mutex(tc->con_dev,
+ drvdata->csdev);
else
/* otherwise remove reference from CTI */
tc->con_dev = NULL;
@@ -646,8 +652,6 @@ 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 +799,27 @@ 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 +926,8 @@ 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/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index a843f9d5c737..fff565d1cb42 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -211,8 +211,8 @@ void coresight_release_platform_data(struct coresight_device *csdev,
struct coresight_platform_data *pdata);
struct coresight_device *
coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
-void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
- struct coresight_device *ect_csdev);
+void coresight_add_helper_mutex(struct coresight_device *csdev,
+ struct coresight_device *helper);
void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
struct coresight_device *coresight_get_percpu_sink(int cpu);
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 464ba5e1343b..dd78e9fcfc4d 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -148,6 +148,10 @@ int coresight_make_links(struct coresight_device *orig,
char *outs = NULL, *ins = NULL;
struct coresight_sysfs_link *link = NULL;
+ /* Helper devices aren't shown in sysfs */
+ if (conn->dest_port == -1 && conn->src_port == -1)
+ return 0;
+
do {
outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
"out:%d", conn->src_port);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index d2739a0286f1..ed37552761e4 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;
};
/**
@@ -237,8 +228,6 @@ struct coresight_sysfs_link {
* from source to that sink.
* @ea: Device attribute for sink representation under PMU directory.
* @def_sink: cached reference to default sink found for this device.
- * @ect_dev: Associated cross trigger device. Not part of the trace data
- * path or connections.
* @nr_links: number of sysfs links created to other components from this
* device. These will appear in the "connections" group.
* @has_conns_grp: Have added a "connections" group for sysfs links.
@@ -261,12 +250,9 @@ 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;
@@ -378,23 +364,11 @@ 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)
--
2.34.1On 29/03/2023 12:53, James Clark wrote:
> 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@arm.com>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 99 ++++++-------------
> .../hwtracing/coresight/coresight-cti-core.c | 52 +++++-----
> .../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
> drivers/hwtracing/coresight/coresight-cti.h | 4 +-
> drivers/hwtracing/coresight/coresight-priv.h | 4 +-
> drivers/hwtracing/coresight/coresight-sysfs.c | 4 +
> include/linux/coresight.h | 30 +-----
> 7 files changed, 70 insertions(+), 127 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 65f5bd8516d8..458d91b4e23f 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -254,60 +254,39 @@ 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
> + * Add a helper as an output device while holding the coresight_mutex
> * to avoid a race with coresight_enable that may try to use this value.
> */
> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
> - struct coresight_device *ect_csdev)
> +void coresight_add_helper_mutex(struct coresight_device *csdev,
> + struct coresight_device *helper)
minor nit: It may be a good idea to rename this, in line with the
kernel naming convention :
coresight_add_helper_unlocked()
Or if this is the only variant, it is OK to leave it as :
coresight_add_helper()
with a big fat comment in the function description to indicate
that it takes the mutex and may be even add a :
might_sleep() and lockdep_assert_not_held(&coresight_mutex);
in the function.
> {
> + int i;
> + struct coresight_connection conn = {};
> +
> mutex_lock(&coresight_mutex);
> - csdev->ect_dev = ect_csdev;
> + conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
> + conn.dest_dev = helper;
> + conn.dest_port = conn.src_port = -1;
> + conn.src_dev = csdev;
> +
> + /*
> + * Check for duplicates because this is called every time a helper
> + * device is re-loaded. Existing connections will get re-linked
> + * automatically.
> + */
Thanks for adding this comment here. It does look like the already added
output connection to the "origin" device would automatically resolve the
connection and add in the "in-connection" to the CTI device.
> + for (i = 0; i < csdev->pdata->nr_outconns; ++i)
> + if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
> + goto unlock;
> +
> + coresight_add_out_conn(csdev->dev.parent, csdev->pdata, &conn);
This makes me wonder if we should return the new connection in
coresight_add_out_conn() in case of success, rather than assuming the
last one (which is always the case though.).
i.e.,
new_conn = coresight_add_out_conn(...)
if (new_conn)
coresight_add_in_conn(new_conn);
> + coresight_add_in_conn(
> + csdev->pdata->out_conns[csdev->pdata->nr_outconns - 1]);
> +
> +unlock:
> mutex_unlock(&coresight_mutex);
> }
> -EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
> +EXPORT_SYMBOL_GPL(coresight_add_helper_mutex);
>
> static int coresight_enable_sink(struct coresight_device *csdev,
> enum cs_mode mode, void *data)
> @@ -321,12 +300,8 @@ 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;
> @@ -344,7 +319,6 @@ 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;
> }
>
> @@ -369,17 +343,11 @@ static int coresight_enable_link(struct coresight_device *csdev,
> return PTR_ERR(outconn);
>
> if (link_ops(csdev)->enable) {
> - ret = coresight_control_assoc_ectdev(csdev, true);
> - if (!ret) {
> - ret = link_ops(csdev)->enable(csdev, inconn, outconn);
> - if (ret)
> - coresight_control_assoc_ectdev(csdev, false);
> - }
> + ret = link_ops(csdev)->enable(csdev, inconn, outconn);
> + if (!ret)
> + csdev->enable = true;
> }
>
> - if (!ret)
> - csdev->enable = true;
> -
> return ret;
> }
>
> @@ -400,7 +368,6 @@ static void coresight_disable_link(struct coresight_device *csdev,
>
> if (link_ops(csdev)->disable) {
> link_ops(csdev)->disable(csdev, inconn, outconn);
> - coresight_control_assoc_ectdev(csdev, false);
> }
>
> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
> @@ -428,14 +395,9 @@ int coresight_enable_source(struct coresight_device *csdev, void *data,
>
> 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, data, mode);
> - if (ret) {
> - coresight_control_assoc_ectdev(csdev, false);
> + if (ret)
> return ret;
> - }
> }
> csdev->enable = true;
> }
> @@ -499,7 +461,6 @@ bool coresight_disable_source(struct coresight_device *csdev, void *data)
> if (atomic_dec_return(&csdev->refcnt) == 0) {
> if (source_ops(csdev)->disable)
> source_ops(csdev)->disable(csdev, data);
> - coresight_control_assoc_ectdev(csdev, false);
> coresight_disable_helpers(csdev);
> csdev->enable = false;
> }
> diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c b/drivers/hwtracing/coresight/coresight-cti-core.c
> index 277c890a1f1f..db7a2212ec18 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 */
> @@ -571,8 +574,7 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
> * if we found a matching csdev then update the ECT
> * association pointer for the device with this CTI.
> */
> - coresight_set_assoc_ectdev_mutex(csdev,
> - ect_item->csdev);
> + coresight_add_helper_mutex(csdev, ect_item->csdev);
> break;
> }
> }
> @@ -582,26 +584,30 @@ static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
>
> /*
> * Removing the associated devices is easier.
> - * A CTI will not have a value for csdev->ect_dev.
> */
> static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
> {
> struct cti_drvdata *ctidrv;
> struct cti_trig_con *tc;
> + union coresight_dev_subtype cti_subtype = {
> + .helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
> + };
> + struct coresight_device *cti_csdev = coresight_find_output_type(
> + csdev->pdata, CORESIGHT_DEV_TYPE_HELPER, cti_subtype);
minor nit: Please could we split the initialisation ? Or at least move
this after the next variable declaration below ?
Rest looks fine to me.
Suzuki
> 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);
> }
> @@ -630,8 +636,8 @@ static void cti_update_conn_xrefs(struct cti_drvdata *drvdata)
> /* if we can set the sysfs link */
> if (cti_add_sysfs_link(drvdata, tc))
> /* set the CTI/csdev association */
> - coresight_set_assoc_ectdev_mutex(tc->con_dev,
> - drvdata->csdev);
> + coresight_add_helper_mutex(tc->con_dev,
> + drvdata->csdev);
> else
> /* otherwise remove reference from CTI */
> tc->con_dev = NULL;
> @@ -646,8 +652,6 @@ 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 +799,27 @@ 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 +926,8 @@ 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/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index a843f9d5c737..fff565d1cb42 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -211,8 +211,8 @@ void coresight_release_platform_data(struct coresight_device *csdev,
> struct coresight_platform_data *pdata);
> struct coresight_device *
> coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
> - struct coresight_device *ect_csdev);
> +void coresight_add_helper_mutex(struct coresight_device *csdev,
> + struct coresight_device *helper);
>
> void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
> struct coresight_device *coresight_get_percpu_sink(int cpu);
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> index 464ba5e1343b..dd78e9fcfc4d 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -148,6 +148,10 @@ int coresight_make_links(struct coresight_device *orig,
> char *outs = NULL, *ins = NULL;
> struct coresight_sysfs_link *link = NULL;
>
> + /* Helper devices aren't shown in sysfs */
> + if (conn->dest_port == -1 && conn->src_port == -1)
> + return 0;
> +
> do {
> outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
> "out:%d", conn->src_port);
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index d2739a0286f1..ed37552761e4 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;
> };
>
> /**
> @@ -237,8 +228,6 @@ struct coresight_sysfs_link {
> * from source to that sink.
> * @ea: Device attribute for sink representation under PMU directory.
> * @def_sink: cached reference to default sink found for this device.
> - * @ect_dev: Associated cross trigger device. Not part of the trace data
> - * path or connections.
> * @nr_links: number of sysfs links created to other components from this
> * device. These will appear in the "connections" group.
> * @has_conns_grp: Have added a "connections" group for sysfs links.
> @@ -261,12 +250,9 @@ 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;
> @@ -378,23 +364,11 @@ 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)
On 04/04/2023 10:21, Suzuki K Poulose wrote:
> On 29/03/2023 12:53, James Clark wrote:
>> 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@arm.com>
>> ---
>> drivers/hwtracing/coresight/coresight-core.c | 99 ++++++-------------
>> .../hwtracing/coresight/coresight-cti-core.c | 52 +++++-----
>> .../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
>> drivers/hwtracing/coresight/coresight-cti.h | 4 +-
>> drivers/hwtracing/coresight/coresight-priv.h | 4 +-
>> drivers/hwtracing/coresight/coresight-sysfs.c | 4 +
>> include/linux/coresight.h | 30 +-----
>> 7 files changed, 70 insertions(+), 127 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>> b/drivers/hwtracing/coresight/coresight-core.c
>> index 65f5bd8516d8..458d91b4e23f 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -254,60 +254,39 @@ 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
>> + * Add a helper as an output device while holding the coresight_mutex
>> * to avoid a race with coresight_enable that may try to use this
>> value.
>> */
>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>> - struct coresight_device *ect_csdev)
>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>> + struct coresight_device *helper)
>
> minor nit: It may be a good idea to rename this, in line with the
> kernel naming convention :
>
> coresight_add_helper_unlocked()
>
> Or if this is the only variant, it is OK to leave it as :
> coresight_add_helper()
> with a big fat comment in the function description to indicate
> that it takes the mutex and may be even add a :
>
There is already a bit of a comment in the description but I can expand
on it more.
> might_sleep() and lockdep_assert_not_held(&coresight_mutex);
>
> in the function.
>
I'm not sure if lockdep_assert_not_held() would be right because
sometimes it could be held if another device is being created at the
same time? Or something like a session is started at the same time a CTI
device is added.
>> {
>> + int i;
>> + struct coresight_connection conn = {};
>> +
>> mutex_lock(&coresight_mutex);
>> - csdev->ect_dev = ect_csdev;
>> + conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
>> + conn.dest_dev = helper;
>> + conn.dest_port = conn.src_port = -1;
>> + conn.src_dev = csdev;
>> +
>> + /*
>> + * Check for duplicates because this is called every time a helper
>> + * device is re-loaded. Existing connections will get re-linked
>> + * automatically.
>> + */
>
> Thanks for adding this comment here. It does look like the already added
> output connection to the "origin" device would automatically resolve the
> connection and add in the "in-connection" to the CTI device.
>
>> + for (i = 0; i < csdev->pdata->nr_outconns; ++i)
>> + if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
>> + goto unlock;
>> +
>> + coresight_add_out_conn(csdev->dev.parent, csdev->pdata, &conn);
>
> This makes me wonder if we should return the new connection in
> coresight_add_out_conn() in case of success, rather than assuming the
> last one (which is always the case though.).
>
> i.e.,
> new_conn = coresight_add_out_conn(...)
> if (new_conn)
> coresight_add_in_conn(new_conn);
>
Yeah I thought about doing that too, will change it.
>> + coresight_add_in_conn(
>> + csdev->pdata->out_conns[csdev->pdata->nr_outconns - 1]);
>> +
>> +unlock:
>> mutex_unlock(&coresight_mutex);
>> }
>> -EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
>> +EXPORT_SYMBOL_GPL(coresight_add_helper_mutex);
>> static int coresight_enable_sink(struct coresight_device *csdev,
>> enum cs_mode mode, void *data)
>> @@ -321,12 +300,8 @@ 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;
>> @@ -344,7 +319,6 @@ 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;
>> }
>> @@ -369,17 +343,11 @@ static int coresight_enable_link(struct
>> coresight_device *csdev,
>> return PTR_ERR(outconn);
>> if (link_ops(csdev)->enable) {
>> - ret = coresight_control_assoc_ectdev(csdev, true);
>> - if (!ret) {
>> - ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>> - if (ret)
>> - coresight_control_assoc_ectdev(csdev, false);
>> - }
>> + ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>> + if (!ret)
>> + csdev->enable = true;
>> }
>> - if (!ret)
>> - csdev->enable = true;
>> -
>> return ret;
>> }
>> @@ -400,7 +368,6 @@ static void coresight_disable_link(struct
>> coresight_device *csdev,
>> if (link_ops(csdev)->disable) {
>> link_ops(csdev)->disable(csdev, inconn, outconn);
>> - coresight_control_assoc_ectdev(csdev, false);
>> }
>> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
>> @@ -428,14 +395,9 @@ int coresight_enable_source(struct
>> coresight_device *csdev, void *data,
>> 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, data, mode);
>> - if (ret) {
>> - coresight_control_assoc_ectdev(csdev, false);
>> + if (ret)
>> return ret;
>> - }
>> }
>> csdev->enable = true;
>> }
>> @@ -499,7 +461,6 @@ bool coresight_disable_source(struct
>> coresight_device *csdev, void *data)
>> if (atomic_dec_return(&csdev->refcnt) == 0) {
>> if (source_ops(csdev)->disable)
>> source_ops(csdev)->disable(csdev, data);
>> - coresight_control_assoc_ectdev(csdev, false);
>> coresight_disable_helpers(csdev);
>> csdev->enable = false;
>> }
>> diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c
>> b/drivers/hwtracing/coresight/coresight-cti-core.c
>> index 277c890a1f1f..db7a2212ec18 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 */
>> @@ -571,8 +574,7 @@ static void cti_add_assoc_to_csdev(struct
>> coresight_device *csdev)
>> * if we found a matching csdev then update the ECT
>> * association pointer for the device with this CTI.
>> */
>> - coresight_set_assoc_ectdev_mutex(csdev,
>> - ect_item->csdev);
>> + coresight_add_helper_mutex(csdev, ect_item->csdev);
>> break;
>> }
>> }
>> @@ -582,26 +584,30 @@ static void cti_add_assoc_to_csdev(struct
>> coresight_device *csdev)
>> /*
>> * Removing the associated devices is easier.
>> - * A CTI will not have a value for csdev->ect_dev.
>> */
>> static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
>> {
>> struct cti_drvdata *ctidrv;
>> struct cti_trig_con *tc;
>> + union coresight_dev_subtype cti_subtype = {
>> + .helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
>> + };
>> + struct coresight_device *cti_csdev = coresight_find_output_type(
>> + csdev->pdata, CORESIGHT_DEV_TYPE_HELPER, cti_subtype);
>
> minor nit: Please could we split the initialisation ? Or at least move
> this after the next variable declaration below ?
>
>
> Rest looks fine to me.
>
> Suzuki
>
>> 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);
>> }
>> @@ -630,8 +636,8 @@ static void cti_update_conn_xrefs(struct
>> cti_drvdata *drvdata)
>> /* if we can set the sysfs link */
>> if (cti_add_sysfs_link(drvdata, tc))
>> /* set the CTI/csdev association */
>> - coresight_set_assoc_ectdev_mutex(tc->con_dev,
>> - drvdata->csdev);
>> + coresight_add_helper_mutex(tc->con_dev,
>> + drvdata->csdev);
>> else
>> /* otherwise remove reference from CTI */
>> tc->con_dev = NULL;
>> @@ -646,8 +652,6 @@ 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 +799,27 @@ 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 +926,8 @@ 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/drivers/hwtracing/coresight/coresight-priv.h
>> b/drivers/hwtracing/coresight/coresight-priv.h
>> index a843f9d5c737..fff565d1cb42 100644
>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>> @@ -211,8 +211,8 @@ void coresight_release_platform_data(struct
>> coresight_device *csdev,
>> struct coresight_platform_data *pdata);
>> struct coresight_device *
>> coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>> - struct coresight_device *ect_csdev);
>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>> + struct coresight_device *helper);
>> void coresight_set_percpu_sink(int cpu, struct coresight_device
>> *csdev);
>> struct coresight_device *coresight_get_percpu_sink(int cpu);
>> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c
>> b/drivers/hwtracing/coresight/coresight-sysfs.c
>> index 464ba5e1343b..dd78e9fcfc4d 100644
>> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
>> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
>> @@ -148,6 +148,10 @@ int coresight_make_links(struct coresight_device
>> *orig,
>> char *outs = NULL, *ins = NULL;
>> struct coresight_sysfs_link *link = NULL;
>> + /* Helper devices aren't shown in sysfs */
>> + if (conn->dest_port == -1 && conn->src_port == -1)
>> + return 0;
>> +
>> do {
>> outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
>> "out:%d", conn->src_port);
>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>> index d2739a0286f1..ed37552761e4 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;
>> };
>> /**
>> @@ -237,8 +228,6 @@ struct coresight_sysfs_link {
>> * from source to that sink.
>> * @ea: Device attribute for sink representation under PMU
>> directory.
>> * @def_sink: cached reference to default sink found for this
>> device.
>> - * @ect_dev: Associated cross trigger device. Not part of the
>> trace data
>> - * path or connections.
>> * @nr_links: number of sysfs links created to other components
>> from this
>> * device. These will appear in the "connections" group.
>> * @has_conns_grp: Have added a "connections" group for sysfs links.
>> @@ -261,12 +250,9 @@ 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;
>> @@ -378,23 +364,11 @@ 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)
>
On 04/04/2023 13:55, James Clark wrote:
>
>
> On 04/04/2023 10:21, Suzuki K Poulose wrote:
>> On 29/03/2023 12:53, James Clark wrote:
>>> 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@arm.com>
>>> ---
>>> drivers/hwtracing/coresight/coresight-core.c | 99 ++++++-------------
>>> .../hwtracing/coresight/coresight-cti-core.c | 52 +++++-----
>>> .../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
>>> drivers/hwtracing/coresight/coresight-cti.h | 4 +-
>>> drivers/hwtracing/coresight/coresight-priv.h | 4 +-
>>> drivers/hwtracing/coresight/coresight-sysfs.c | 4 +
>>> include/linux/coresight.h | 30 +-----
>>> 7 files changed, 70 insertions(+), 127 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>> b/drivers/hwtracing/coresight/coresight-core.c
>>> index 65f5bd8516d8..458d91b4e23f 100644
>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>> @@ -254,60 +254,39 @@ 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
>>> + * Add a helper as an output device while holding the coresight_mutex
>>> * to avoid a race with coresight_enable that may try to use this
>>> value.
>>> */
>>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>>> - struct coresight_device *ect_csdev)
>>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>>> + struct coresight_device *helper)
>>
>> minor nit: It may be a good idea to rename this, in line with the
>> kernel naming convention :
>>
>> coresight_add_helper_unlocked()
>>
>> Or if this is the only variant, it is OK to leave it as :
>> coresight_add_helper()
>> with a big fat comment in the function description to indicate
>> that it takes the mutex and may be even add a :
>>
> There is already a bit of a comment in the description but I can expand
> on it more.
>
>> might_sleep() and lockdep_assert_not_held(&coresight_mutex);
>>
>> in the function.
>>
>
> I'm not sure if lockdep_assert_not_held() would be right because
> sometimes it could be held if another device is being created at the
> same time? Or something like a session is started at the same time a CTI
> device is added.
>
Oh I see it's not for any task, it's just for the current one. That
makes sense then I can add it.
Although it looks like it only warns when lockdep is enabled, but don't
you get a warning anyway if you try to take the lock twice with lockdep
enabled? So I'm not sure why we would add lockdep_assert_not_held() here
and not on all the mutex_lock() calls?
>>> {
>>> + int i;
>>> + struct coresight_connection conn = {};
>>> +
>>> mutex_lock(&coresight_mutex);
>>> - csdev->ect_dev = ect_csdev;
>>> + conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
>>> + conn.dest_dev = helper;
>>> + conn.dest_port = conn.src_port = -1;
>>> + conn.src_dev = csdev;
>>> +
>>> + /*
>>> + * Check for duplicates because this is called every time a helper
>>> + * device is re-loaded. Existing connections will get re-linked
>>> + * automatically.
>>> + */
>>
>> Thanks for adding this comment here. It does look like the already added
>> output connection to the "origin" device would automatically resolve the
>> connection and add in the "in-connection" to the CTI device.
>>
>>> + for (i = 0; i < csdev->pdata->nr_outconns; ++i)
>>> + if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
>>> + goto unlock;
>>> +
>>> + coresight_add_out_conn(csdev->dev.parent, csdev->pdata, &conn);
>>
>> This makes me wonder if we should return the new connection in
>> coresight_add_out_conn() in case of success, rather than assuming the
>> last one (which is always the case though.).
>>
>> i.e.,
>> new_conn = coresight_add_out_conn(...)
>> if (new_conn)
>> coresight_add_in_conn(new_conn);
>>
>
> Yeah I thought about doing that too, will change it.
>
>>> + coresight_add_in_conn(
>>> + csdev->pdata->out_conns[csdev->pdata->nr_outconns - 1]);
>>> +
>>> +unlock:
>>> mutex_unlock(&coresight_mutex);
>>> }
>>> -EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
>>> +EXPORT_SYMBOL_GPL(coresight_add_helper_mutex);
>>> static int coresight_enable_sink(struct coresight_device *csdev,
>>> enum cs_mode mode, void *data)
>>> @@ -321,12 +300,8 @@ 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;
>>> @@ -344,7 +319,6 @@ 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;
>>> }
>>> @@ -369,17 +343,11 @@ static int coresight_enable_link(struct
>>> coresight_device *csdev,
>>> return PTR_ERR(outconn);
>>> if (link_ops(csdev)->enable) {
>>> - ret = coresight_control_assoc_ectdev(csdev, true);
>>> - if (!ret) {
>>> - ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>>> - if (ret)
>>> - coresight_control_assoc_ectdev(csdev, false);
>>> - }
>>> + ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>>> + if (!ret)
>>> + csdev->enable = true;
>>> }
>>> - if (!ret)
>>> - csdev->enable = true;
>>> -
>>> return ret;
>>> }
>>> @@ -400,7 +368,6 @@ static void coresight_disable_link(struct
>>> coresight_device *csdev,
>>> if (link_ops(csdev)->disable) {
>>> link_ops(csdev)->disable(csdev, inconn, outconn);
>>> - coresight_control_assoc_ectdev(csdev, false);
>>> }
>>> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
>>> @@ -428,14 +395,9 @@ int coresight_enable_source(struct
>>> coresight_device *csdev, void *data,
>>> 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, data, mode);
>>> - if (ret) {
>>> - coresight_control_assoc_ectdev(csdev, false);
>>> + if (ret)
>>> return ret;
>>> - }
>>> }
>>> csdev->enable = true;
>>> }
>>> @@ -499,7 +461,6 @@ bool coresight_disable_source(struct
>>> coresight_device *csdev, void *data)
>>> if (atomic_dec_return(&csdev->refcnt) == 0) {
>>> if (source_ops(csdev)->disable)
>>> source_ops(csdev)->disable(csdev, data);
>>> - coresight_control_assoc_ectdev(csdev, false);
>>> coresight_disable_helpers(csdev);
>>> csdev->enable = false;
>>> }
>>> diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c
>>> b/drivers/hwtracing/coresight/coresight-cti-core.c
>>> index 277c890a1f1f..db7a2212ec18 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 */
>>> @@ -571,8 +574,7 @@ static void cti_add_assoc_to_csdev(struct
>>> coresight_device *csdev)
>>> * if we found a matching csdev then update the ECT
>>> * association pointer for the device with this CTI.
>>> */
>>> - coresight_set_assoc_ectdev_mutex(csdev,
>>> - ect_item->csdev);
>>> + coresight_add_helper_mutex(csdev, ect_item->csdev);
>>> break;
>>> }
>>> }
>>> @@ -582,26 +584,30 @@ static void cti_add_assoc_to_csdev(struct
>>> coresight_device *csdev)
>>> /*
>>> * Removing the associated devices is easier.
>>> - * A CTI will not have a value for csdev->ect_dev.
>>> */
>>> static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
>>> {
>>> struct cti_drvdata *ctidrv;
>>> struct cti_trig_con *tc;
>>> + union coresight_dev_subtype cti_subtype = {
>>> + .helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
>>> + };
>>> + struct coresight_device *cti_csdev = coresight_find_output_type(
>>> + csdev->pdata, CORESIGHT_DEV_TYPE_HELPER, cti_subtype);
>>
>> minor nit: Please could we split the initialisation ? Or at least move
>> this after the next variable declaration below ?
>>
>>
>> Rest looks fine to me.
>>
>> Suzuki
>>
>>> 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);
>>> }
>>> @@ -630,8 +636,8 @@ static void cti_update_conn_xrefs(struct
>>> cti_drvdata *drvdata)
>>> /* if we can set the sysfs link */
>>> if (cti_add_sysfs_link(drvdata, tc))
>>> /* set the CTI/csdev association */
>>> - coresight_set_assoc_ectdev_mutex(tc->con_dev,
>>> - drvdata->csdev);
>>> + coresight_add_helper_mutex(tc->con_dev,
>>> + drvdata->csdev);
>>> else
>>> /* otherwise remove reference from CTI */
>>> tc->con_dev = NULL;
>>> @@ -646,8 +652,6 @@ 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 +799,27 @@ 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 +926,8 @@ 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/drivers/hwtracing/coresight/coresight-priv.h
>>> b/drivers/hwtracing/coresight/coresight-priv.h
>>> index a843f9d5c737..fff565d1cb42 100644
>>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>>> @@ -211,8 +211,8 @@ void coresight_release_platform_data(struct
>>> coresight_device *csdev,
>>> struct coresight_platform_data *pdata);
>>> struct coresight_device *
>>> coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
>>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>>> - struct coresight_device *ect_csdev);
>>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>>> + struct coresight_device *helper);
>>> void coresight_set_percpu_sink(int cpu, struct coresight_device
>>> *csdev);
>>> struct coresight_device *coresight_get_percpu_sink(int cpu);
>>> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c
>>> b/drivers/hwtracing/coresight/coresight-sysfs.c
>>> index 464ba5e1343b..dd78e9fcfc4d 100644
>>> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
>>> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
>>> @@ -148,6 +148,10 @@ int coresight_make_links(struct coresight_device
>>> *orig,
>>> char *outs = NULL, *ins = NULL;
>>> struct coresight_sysfs_link *link = NULL;
>>> + /* Helper devices aren't shown in sysfs */
>>> + if (conn->dest_port == -1 && conn->src_port == -1)
>>> + return 0;
>>> +
>>> do {
>>> outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
>>> "out:%d", conn->src_port);
>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>>> index d2739a0286f1..ed37552761e4 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;
>>> };
>>> /**
>>> @@ -237,8 +228,6 @@ struct coresight_sysfs_link {
>>> * from source to that sink.
>>> * @ea: Device attribute for sink representation under PMU
>>> directory.
>>> * @def_sink: cached reference to default sink found for this
>>> device.
>>> - * @ect_dev: Associated cross trigger device. Not part of the
>>> trace data
>>> - * path or connections.
>>> * @nr_links: number of sysfs links created to other components
>>> from this
>>> * device. These will appear in the "connections" group.
>>> * @has_conns_grp: Have added a "connections" group for sysfs links.
>>> @@ -261,12 +250,9 @@ 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;
>>> @@ -378,23 +364,11 @@ 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)
>>
On 04/04/2023 14:04, James Clark wrote:
>
>
> On 04/04/2023 13:55, James Clark wrote:
>>
>>
>> On 04/04/2023 10:21, Suzuki K Poulose wrote:
>>> On 29/03/2023 12:53, James Clark wrote:
>>>> 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@arm.com>
>>>> ---
>>>> drivers/hwtracing/coresight/coresight-core.c | 99 ++++++-------------
>>>> .../hwtracing/coresight/coresight-cti-core.c | 52 +++++-----
>>>> .../hwtracing/coresight/coresight-cti-sysfs.c | 4 +-
>>>> drivers/hwtracing/coresight/coresight-cti.h | 4 +-
>>>> drivers/hwtracing/coresight/coresight-priv.h | 4 +-
>>>> drivers/hwtracing/coresight/coresight-sysfs.c | 4 +
>>>> include/linux/coresight.h | 30 +-----
>>>> 7 files changed, 70 insertions(+), 127 deletions(-)
>>>>
>>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>>> b/drivers/hwtracing/coresight/coresight-core.c
>>>> index 65f5bd8516d8..458d91b4e23f 100644
>>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>>> @@ -254,60 +254,39 @@ 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
>>>> + * Add a helper as an output device while holding the coresight_mutex
>>>> * to avoid a race with coresight_enable that may try to use this
>>>> value.
>>>> */
>>>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>>>> - struct coresight_device *ect_csdev)
>>>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>>>> + struct coresight_device *helper)
>>>
>>> minor nit: It may be a good idea to rename this, in line with the
>>> kernel naming convention :
>>>
>>> coresight_add_helper_unlocked()
>>>
>>> Or if this is the only variant, it is OK to leave it as :
>>> coresight_add_helper()
>>> with a big fat comment in the function description to indicate
>>> that it takes the mutex and may be even add a :
>>>
>> There is already a bit of a comment in the description but I can expand
>> on it more.
>>
>>> might_sleep() and lockdep_assert_not_held(&coresight_mutex);
>>>
>>> in the function.
>>>
>>
>> I'm not sure if lockdep_assert_not_held() would be right because
>> sometimes it could be held if another device is being created at the
>> same time? Or something like a session is started at the same time a CTI
>> device is added.
>>
>
> Oh I see it's not for any task, it's just for the current one. That
> makes sense then I can add it.
>
> Although it looks like it only warns when lockdep is enabled, but don't
> you get a warning anyway if you try to take the lock twice with lockdep
> enabled?
Thats true, you could ignore the lockdep check.
So I'm not sure why we would add lockdep_assert_not_held() here
> and not on all the mutex_lock() calls?\
Ah. I double checked this and the coresight_mutex is static and local to
coresight-core.c. So there is no point in talking about locking for
external users. So I would just leave out any suffixes and simply use
the lockdep check implicit from mutex_lock().
Suzuki
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