[PATCH v2 0/5] coresight: syscfg: dynamic load

[PATCH v2 0/5] coresight: syscfg: dynamic load

[Mike Leach]

1) API updated to allow dynamic load and unload of configurations and
features. Dependency management between loaded sets is added.

2) New configuration and feature sets can be added using a loadable module.
An example in /samples/coresight is provided to demonstrate this.

3) configfs can be used to activate a configuration which will then be used
when controlling tracing using sysfs.

Applies and tested on coresight/next - which is 5.15-rc1


Changes since v1:

a) Original set split to divide related changes into smaller sets.
Removed RFC flag.

b) Revised config activation for sysfs to simplify common function.
(patch 4). 

c) Minor changes requested by Mathieu added.

Mike Leach (5):
  coresight: syscfg: Update API to allow dynamic load and unload
  coresight: syscfg: Update load API for config loadable modules
  coresight: syscfg: Example CoreSight configuration loadable module
  coresight: configfs: Allow configfs to activate configuration
  Documentation: coresight: Update coresight configuration docs

 .../trace/coresight/coresight-config.rst      |  19 ++
 MAINTAINERS                                   |   1 +
 .../coresight/coresight-cfg-preload.c         |   9 +-
 .../hwtracing/coresight/coresight-config.h    |   9 +-
 .../coresight/coresight-etm4x-core.c          |  11 +-
 .../coresight/coresight-syscfg-configfs.c     |  87 +++++
 .../coresight/coresight-syscfg-configfs.h     |   4 +
 .../hwtracing/coresight/coresight-syscfg.c    | 315 ++++++++++++++++--
 .../hwtracing/coresight/coresight-syscfg.h    |  39 ++-
 samples/Kconfig                               |   9 +
 samples/Makefile                              |   1 +
 samples/coresight/Makefile                    |   4 +
 samples/coresight/coresight-cfg-sample.c      |  73 ++++
 13 files changed, 546 insertions(+), 35 deletions(-)
 create mode 100644 samples/coresight/Makefile
 create mode 100644 samples/coresight/coresight-cfg-sample.c

-- 
2.17.1


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[PATCH v2 1/5] coresight: syscfg: Update API to allow dynamic load and unload

[Mike Leach]

Update the load API to permit the runtime loading and unloading of new
configurations and features.

On load, configurations and features are tagged with a "load owner" that
is used to determine sets that were loaded together in a given API call.

To unload the API uses the load owner to unload all elements previously
loaded by that owner.

The API also records the order in which different owners loaded
their elements into the system. Later loading configurations can use
previously loaded features, creating load dependencies. Therefore unload
is enforced strictly in the reverse order to load.

A load owner will be an additional loadable module, or a configuration
created or loaded via configfs.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../coresight/coresight-cfg-preload.c         |   9 +-
 .../hwtracing/coresight/coresight-config.h    |   9 +-
 .../coresight/coresight-syscfg-configfs.c     |  20 +++
 .../coresight/coresight-syscfg-configfs.h     |   2 +
 .../hwtracing/coresight/coresight-syscfg.c    | 154 +++++++++++++++++-
 .../hwtracing/coresight/coresight-syscfg.h    |  30 +++-
 6 files changed, 216 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-cfg-preload.c b/drivers/hwtracing/coresight/coresight-cfg-preload.c
index 751af3710d56..e237a4edfa09 100644
--- a/drivers/hwtracing/coresight/coresight-cfg-preload.c
+++ b/drivers/hwtracing/coresight/coresight-cfg-preload.c
@@ -24,8 +24,13 @@ static struct cscfg_config_desc *preload_cfgs[] = {
 	NULL
 };
 
+static struct cscfg_load_owner_info preload_owner = {
+	.type = CSCFG_OWNER_PRELOAD,
+};
+
 /* preload called on initialisation */
-int cscfg_preload(void)
+int cscfg_preload(void *owner_handle)
 {
-	return cscfg_load_config_sets(preload_cfgs, preload_feats);
+	preload_owner.owner_handle = owner_handle;
+	return cscfg_load_config_sets(preload_cfgs, preload_feats, &preload_owner);
 }
diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
index 25eb6c632692..9bd44b940add 100644
--- a/drivers/hwtracing/coresight/coresight-config.h
+++ b/drivers/hwtracing/coresight/coresight-config.h
@@ -97,6 +97,8 @@ struct cscfg_regval_desc {
  * @params_desc: array of parameters used.
  * @nr_regs:	 number of registers used.
  * @regs_desc:	 array of registers used.
+ * @load_owner:	 handle to load owner for dynamic load and unload of features.
+ * @fs_group:	 reference to configfs group for dynamic unload.
  */
 struct cscfg_feature_desc {
 	const char *name;
@@ -107,6 +109,8 @@ struct cscfg_feature_desc {
 	struct cscfg_parameter_desc *params_desc;
 	int nr_regs;
 	struct cscfg_regval_desc *regs_desc;
+	void *load_owner;
+	struct config_group *fs_group;
 };
 
 /**
@@ -128,7 +132,8 @@ struct cscfg_feature_desc {
  * @presets:		Array of preset values.
  * @event_ea:		Extended attribute for perf event value
  * @active_cnt:		ref count for activate on this configuration.
- *
+ * @load_owner:		handle to load owner for dynamic load and unload of configs.
+ * @fs_group:		reference to configfs group for dynamic unload.
  */
 struct cscfg_config_desc {
 	const char *name;
@@ -141,6 +146,8 @@ struct cscfg_config_desc {
 	const u64 *presets; /* nr_presets * nr_total_params */
 	struct dev_ext_attribute *event_ea;
 	atomic_t active_cnt;
+	void *load_owner;
+	struct config_group *fs_group;
 };
 
 /**
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
index c547816b9000..345a62f1b728 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
@@ -334,9 +334,19 @@ int cscfg_configfs_add_config(struct cscfg_config_desc *config_desc)
 	if (IS_ERR(new_group))
 		return PTR_ERR(new_group);
 	err =  configfs_register_group(&cscfg_configs_grp, new_group);
+	if (!err)
+		config_desc->fs_group = new_group;
 	return err;
 }
 
+void cscfg_configfs_del_config(struct cscfg_config_desc *config_desc)
+{
+	if (config_desc->fs_group) {
+		configfs_unregister_group(config_desc->fs_group);
+		config_desc->fs_group = NULL;
+	}
+}
+
 static struct config_item_type cscfg_features_type = {
 	.ct_owner = THIS_MODULE,
 };
@@ -358,9 +368,19 @@ int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc)
 	if (IS_ERR(new_group))
 		return PTR_ERR(new_group);
 	err =  configfs_register_group(&cscfg_features_grp, new_group);
+	if (!err)
+		feat_desc->fs_group = new_group;
 	return err;
 }
 
+void cscfg_configfs_del_feature(struct cscfg_feature_desc *feat_desc)
+{
+	if (feat_desc->fs_group) {
+		configfs_unregister_group(feat_desc->fs_group);
+		feat_desc->fs_group = NULL;
+	}
+}
+
 int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr)
 {
 	struct configfs_subsystem *subsys;
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
index 7d6ffe35ca4c..ea1e54d29f7f 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
@@ -41,5 +41,7 @@ int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr);
 void cscfg_configfs_release(struct cscfg_manager *cscfg_mgr);
 int cscfg_configfs_add_config(struct cscfg_config_desc *config_desc);
 int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc);
+void cscfg_configfs_del_config(struct cscfg_config_desc *config_desc);
+void cscfg_configfs_del_feature(struct cscfg_feature_desc *feat_desc);
 
 #endif /* CORESIGHT_SYSCFG_CONFIGFS_H */
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index fc0760f55c53..9bb0b0913a9a 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -249,6 +249,13 @@ static int cscfg_check_feat_for_cfg(struct cscfg_config_desc *config_desc)
 static int cscfg_load_feat(struct cscfg_feature_desc *feat_desc)
 {
 	int err;
+	struct cscfg_feature_desc *feat_desc_exist;
+
+	/* new feature must have unique name */
+	list_for_each_entry(feat_desc_exist, &cscfg_mgr->feat_desc_list, item) {
+		if (!strcmp(feat_desc_exist->name, feat_desc->name))
+			return -EEXIST;
+	}
 
 	/* add feature to any matching registered devices */
 	err = cscfg_add_feat_to_csdevs(feat_desc);
@@ -266,6 +273,13 @@ static int cscfg_load_feat(struct cscfg_feature_desc *feat_desc)
 static int cscfg_load_config(struct cscfg_config_desc *config_desc)
 {
 	int err;
+	struct cscfg_config_desc *config_desc_exist;
+
+	/* new configuration must have a unique name */
+	list_for_each_entry(config_desc_exist, &cscfg_mgr->config_desc_list, item) {
+		if (!strcmp(config_desc_exist->name, config_desc->name))
+			return -EEXIST;
+	}
 
 	/* validate features are present */
 	err = cscfg_check_feat_for_cfg(config_desc);
@@ -353,6 +367,72 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 	return err;
 }
 
+static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, void *load_owner)
+{
+	struct cscfg_config_csdev *config_csdev, *tmp;
+
+	if (list_empty(&csdev->config_csdev_list))
+		return;
+
+	list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) {
+		if (config_csdev->config_desc->load_owner == load_owner)
+			list_del(&config_csdev->node);
+	}
+}
+
+static void cscfg_remove_owned_csdev_features(struct coresight_device *csdev, void *load_owner)
+{
+	struct cscfg_feature_csdev *feat_csdev, *tmp;
+
+	if (list_empty(&csdev->feature_csdev_list))
+		return;
+
+	list_for_each_entry_safe(feat_csdev, tmp, &csdev->feature_csdev_list, node) {
+		if (feat_csdev->feat_desc->load_owner == load_owner)
+			list_del(&feat_csdev->node);
+	}
+}
+
+/*
+ * removal is relatively easy - just remove from all lists, anything that
+ * matches the owner. Memory for the descriptors will be managed by the owner,
+ * memory for the csdev items is devm_ allocated with the individual csdev
+ * devices.
+ */
+static void cscfg_unload_owned_cfgs_feats(void *load_owner)
+{
+	struct cscfg_config_desc *config_desc, *cfg_tmp;
+	struct cscfg_feature_desc *feat_desc, *feat_tmp;
+	struct cscfg_registered_csdev *csdev_item;
+
+	/* remove from each csdev instance feature and config lists */
+	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
+		/*
+		 * for each csdev, check the loaded lists and remove if
+		 * referenced descriptor is owned
+		 */
+		cscfg_remove_owned_csdev_configs(csdev_item->csdev, load_owner);
+		cscfg_remove_owned_csdev_features(csdev_item->csdev, load_owner);
+	}
+
+	/* remove from the config descriptor lists */
+	list_for_each_entry_safe(config_desc, cfg_tmp, &cscfg_mgr->config_desc_list, item) {
+		if (config_desc->load_owner == load_owner) {
+			cscfg_configfs_del_config(config_desc);
+			etm_perf_del_symlink_cscfg(config_desc);
+			list_del(&config_desc->item);
+		}
+	}
+
+	/* remove from the feature descriptor lists */
+	list_for_each_entry_safe(feat_desc, feat_tmp, &cscfg_mgr->feat_desc_list, item) {
+		if (feat_desc->load_owner == load_owner) {
+			cscfg_configfs_del_feature(feat_desc);
+			list_del(&feat_desc->item);
+		}
+	}
+}
+
 /**
  * cscfg_load_config_sets - API function to load feature and config sets.
  *
@@ -360,13 +440,22 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
  * descriptors and load into the system.
  * Features are loaded first to ensure configuration dependencies can be met.
  *
+ * To facilitate dynamic loading and unloading, features and configurations
+ * have a "load_owner", to allow later unload by the same owner. An owner may
+ * be a loadable module or configuration dynamically created via configfs.
+ * As later loaded configurations can use earlier loaded features, creating load
+ * dependencies, a load order list is maintained. Unload is strictly in the
+ * reverse order to load.
+ *
  * @config_descs: 0 terminated array of configuration descriptors.
  * @feat_descs:   0 terminated array of feature descriptors.
+ * @owner_info:	  Information on the owner of this set.
  */
 int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
-			   struct cscfg_feature_desc **feat_descs)
+			   struct cscfg_feature_desc **feat_descs,
+			   struct cscfg_load_owner_info *owner_info)
 {
-	int err, i = 0;
+	int err = 0, i = 0;
 
 	mutex_lock(&cscfg_mutex);
 
@@ -379,8 +468,10 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 			if (err) {
 				pr_err("coresight-syscfg: Failed to load feature %s\n",
 				       feat_descs[i]->name);
+				cscfg_unload_owned_cfgs_feats(owner_info);
 				goto exit_unlock;
 			}
+			feat_descs[i]->load_owner = owner_info;
 			i++;
 		}
 	}
@@ -395,18 +486,74 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 			if (err) {
 				pr_err("coresight-syscfg: Failed to load configuration %s\n",
 				       config_descs[i]->name);
+				cscfg_unload_owned_cfgs_feats(owner_info);
 				goto exit_unlock;
 			}
+			config_descs[i]->load_owner = owner_info;
 			i++;
 		}
 	}
 
+	/* add the load owner to the load order list */
+	list_add_tail(&owner_info->item, &cscfg_mgr->load_order_list);
+
 exit_unlock:
 	mutex_unlock(&cscfg_mutex);
 	return err;
 }
 EXPORT_SYMBOL_GPL(cscfg_load_config_sets);
 
+/**
+ * cscfg_unload_config_sets - unload a set of configurations by owner.
+ *
+ * Dynamic unload of configuration and feature sets is done on the basis of
+ * the load owner of that set. Later loaded configurations can depend on
+ * features loaded earlier.
+ *
+ * Therefore, unload is only possible if:-
+ * 1) no configurations are active.
+ * 2) the set being unloaded was the last to be loaded to maintain dependencies.
+ *
+ * @owner_info:	Information on owner for set being unloaded.
+ */
+int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
+{
+	int err = 0;
+	struct cscfg_load_owner_info *load_list_item = NULL;
+
+	mutex_lock(&cscfg_mutex);
+
+	/* cannot unload if anything is active */
+	if (atomic_read(&cscfg_mgr->sys_active_cnt)) {
+		err = -EBUSY;
+		goto exit_unlock;
+	}
+
+	/* cannot unload if not last loaded in load order */
+	if (!list_empty(&cscfg_mgr->load_order_list)) {
+		load_list_item = list_last_entry(&cscfg_mgr->load_order_list,
+						 struct cscfg_load_owner_info, item);
+		if (load_list_item != owner_info)
+			load_list_item = NULL;
+	}
+
+	if (!load_list_item) {
+		err = -EINVAL;
+		goto exit_unlock;
+	}
+
+	/* unload all belonging to load_owner */
+	cscfg_unload_owned_cfgs_feats(owner_info);
+
+	/* remove from load order list */
+	list_del(&load_list_item->item);
+
+exit_unlock:
+	mutex_unlock(&cscfg_mutex);
+	return err;
+}
+EXPORT_SYMBOL_GPL(cscfg_unload_config_sets);
+
 /* Handle coresight device registration and add configs and features to devices */
 
 /* iterate through config lists and load matching configs to device */
@@ -826,10 +973,11 @@ int __init cscfg_init(void)
 	INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
 	INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
 	INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
+	INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
 	atomic_set(&cscfg_mgr->sys_active_cnt, 0);
 
 	/* preload built-in configurations */
-	err = cscfg_preload();
+	err = cscfg_preload(THIS_MODULE);
 	if (err)
 		goto exit_err;
 
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 8d018efd6ead..e2b2bdab31aa 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -25,6 +25,7 @@
  * @csdev_desc_list:	List of coresight devices registered with the configuration manager.
  * @feat_desc_list:	List of feature descriptors to load into registered devices.
  * @config_desc_list:	List of system configuration descriptors to load into registered devices.
+ * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
  * @sys_active_cnt:	Total number of active config descriptor references.
  * @cfgfs_subsys:	configfs subsystem used to manage configurations.
  */
@@ -33,6 +34,7 @@ struct cscfg_manager {
 	struct list_head csdev_desc_list;
 	struct list_head feat_desc_list;
 	struct list_head config_desc_list;
+	struct list_head load_order_list;
 	atomic_t sys_active_cnt;
 	struct configfs_subsystem cfgfs_subsys;
 };
@@ -56,10 +58,32 @@ struct cscfg_registered_csdev {
 	struct list_head item;
 };
 
+/* owner types for loading and unloading of config and feature sets */
+enum cscfg_load_owner_type {
+	CSCFG_OWNER_PRELOAD,
+};
+
+/**
+ * Load item - item to add to the load order list allowing dynamic load and
+ *             unload of configurations and features. Caller loading a config
+ *	       set provides a context handle for unload. API ensures that
+ *	       items unloaded strictly in reverse order from load to ensure
+ *	       dependencies are respected.
+ *
+ * @item:		list entry for load order list.
+ * @type:		type of owner - allows interpretation of owner_handle.
+ * @owner_handle:	load context - handle for owner of loaded configs.
+ */
+struct cscfg_load_owner_info {
+	struct list_head item;
+	int type;
+	void *owner_handle;
+};
+
 /* internal core operations for cscfg */
 int __init cscfg_init(void);
 void cscfg_exit(void);
-int cscfg_preload(void);
+int cscfg_preload(void *owner_handle);
 const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
 int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 				int param_idx, u64 value);
@@ -67,7 +91,9 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 
 /* syscfg manager external API */
 int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
-			   struct cscfg_feature_desc **feat_descs);
+			   struct cscfg_feature_desc **feat_descs,
+			   struct cscfg_load_owner_info *owner_info);
+int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info);
 int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags,
 			 struct cscfg_csdev_feat_ops *ops);
 void cscfg_unregister_csdev(struct coresight_device *csdev);
-- 
2.17.1


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[PATCH v2 2/5] coresight: syscfg: Update load API for config loadable modules

[Mike Leach]

CoreSight configurations and features can be added as kernel loadable
modules. This patch updates the load owner API to ensure that the module
cannot be unloaded either:
1) if the config it supplies is in use
2) if the module is not the last in the load order list.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../hwtracing/coresight/coresight-syscfg.c    | 39 ++++++++++++++++++-
 .../hwtracing/coresight/coresight-syscfg.h    |  1 +
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 9bb0b0913a9a..4b91d8d9bc37 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -367,6 +367,26 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 	return err;
 }
 
+/*
+ * Conditionally up reference count on owner to prevent unload.
+ *
+ * module loaded configs need to be locked in to prevent premature unload.
+ */
+static int cscfg_owner_get(struct cscfg_load_owner_info *owner_info)
+{
+	if ((owner_info->type == CSCFG_OWNER_MODULE) &&
+	    (!try_module_get(owner_info->owner_handle)))
+		return -EINVAL;
+	return 0;
+}
+
+/* conditionally lower ref count on an owner */
+static void cscfg_owner_put(struct cscfg_load_owner_info *owner_info)
+{
+	if (owner_info->type == CSCFG_OWNER_MODULE)
+		module_put(owner_info->owner_handle);
+}
+
 static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, void *load_owner)
 {
 	struct cscfg_config_csdev *config_csdev, *tmp;
@@ -496,6 +516,14 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
 
 	/* add the load owner to the load order list */
 	list_add_tail(&owner_info->item, &cscfg_mgr->load_order_list);
+	if (!list_is_singular(&cscfg_mgr->load_order_list)) {
+		/* lock previous item in load order list */
+		err = cscfg_owner_get(list_prev_entry(owner_info, item));
+		if (err) {
+			cscfg_unload_owned_cfgs_feats(owner_info);
+			list_del(&owner_info->item);
+		}
+	}
 
 exit_unlock:
 	mutex_unlock(&cscfg_mutex);
@@ -546,7 +574,11 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
 	cscfg_unload_owned_cfgs_feats(owner_info);
 
 	/* remove from load order list */
-	list_del(&load_list_item->item);
+	if (!list_is_singular(&cscfg_mgr->load_order_list)) {
+		/* unlock previous item in load order list */
+		cscfg_owner_put(list_prev_entry(owner_info, item));
+	}
+	list_del(&owner_info->item);
 
 exit_unlock:
 	mutex_unlock(&cscfg_mutex);
@@ -738,6 +770,10 @@ int cscfg_activate_config(unsigned long cfg_hash)
 
 	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
 		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
+			/* must ensure that config cannot be unloaded in use */
+			err = cscfg_owner_get(config_desc->load_owner);
+			if (err)
+				break;
 			/*
 			 * increment the global active count - control changes to
 			 * active configurations
@@ -778,6 +814,7 @@ void cscfg_deactivate_config(unsigned long cfg_hash)
 		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
 			atomic_dec(&config_desc->active_cnt);
 			atomic_dec(&cscfg_mgr->sys_active_cnt);
+			cscfg_owner_put(config_desc->load_owner);
 			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
 			break;
 		}
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index e2b2bdab31aa..1da37874f70f 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -61,6 +61,7 @@ struct cscfg_registered_csdev {
 /* owner types for loading and unloading of config and feature sets */
 enum cscfg_load_owner_type {
 	CSCFG_OWNER_PRELOAD,
+	CSCFG_OWNER_MODULE,
 };
 
 /**
-- 
2.17.1


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[PATCH v2 3/5] coresight: syscfg: Example CoreSight configuration loadable module

[Mike Leach]

An example of creating a loadable module to add CoreSight configurations
into a system.

In the Kernel samples/coresight directory.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 MAINTAINERS                              |  1 +
 samples/Kconfig                          |  9 +++
 samples/Makefile                         |  1 +
 samples/coresight/Makefile               |  4 ++
 samples/coresight/coresight-cfg-sample.c | 73 ++++++++++++++++++++++++
 5 files changed, 88 insertions(+)
 create mode 100644 samples/coresight/Makefile
 create mode 100644 samples/coresight/coresight-cfg-sample.c

diff --git a/MAINTAINERS b/MAINTAINERS
index eeb4c70b3d5b..73437065e806 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1855,6 +1855,7 @@ F:	Documentation/trace/coresight/*
 F:	drivers/hwtracing/coresight/*
 F:	include/dt-bindings/arm/coresight-cti-dt.h
 F:	include/linux/coresight*
+F:	samples/coresight/*
 F:	tools/perf/arch/arm/util/auxtrace.c
 F:	tools/perf/arch/arm/util/cs-etm.c
 F:	tools/perf/arch/arm/util/cs-etm.h
diff --git a/samples/Kconfig b/samples/Kconfig
index b0503ef058d3..ccd9596c951b 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -223,4 +223,13 @@ config SAMPLE_WATCH_QUEUE
 	  Build example userspace program to use the new mount_notify(),
 	  sb_notify() syscalls and the KEYCTL_WATCH_KEY keyctl() function.
 
+config SAMPLE_CORESIGHT_SYSCFG
+	tristate "Build example loadable module for CoreSight config"
+	depends on CORESIGHT && m
+	help
+	  Build an example loadable module that adds new CoreSight features
+	  and configuration using the CoreSight system configuration API.
+	  This demonstrates how a user may create their own CoreSight
+	  configurations and easily load them into the system at runtime.
+
 endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 087e0988ccc5..6c96297001a8 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_SAMPLE_INTEL_MEI)		+= mei/
 subdir-$(CONFIG_SAMPLE_WATCHDOG)	+= watchdog
 subdir-$(CONFIG_SAMPLE_WATCH_QUEUE)	+= watch_queue
 obj-$(CONFIG_DEBUG_KMEMLEAK_TEST)	+= kmemleak/
+obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
diff --git a/samples/coresight/Makefile b/samples/coresight/Makefile
new file mode 100644
index 000000000000..b3fce4af2347
--- /dev/null
+++ b/samples/coresight/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG) += coresight-cfg-sample.o
+ccflags-y += -I$(srctree)/drivers/hwtracing/coresight
diff --git a/samples/coresight/coresight-cfg-sample.c b/samples/coresight/coresight-cfg-sample.c
new file mode 100644
index 000000000000..25485c80b5e3
--- /dev/null
+++ b/samples/coresight/coresight-cfg-sample.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2020 Linaro Limited. All rights reserved.
+ * Author: Mike Leach <mike.leach@linaro.org>
+ */
+
+#include "coresight-config.h"
+#include "coresight-syscfg.h"
+
+/* create an alternate autofdo configuration */
+
+/* we will provide 4 sets of preset parameter values */
+#define AFDO2_NR_PRESETS	4
+/* the total number of parameters in used features - strobing has 2 */
+#define AFDO2_NR_PARAM_SUM	2
+
+static const char *afdo2_ref_names[] = {
+	"strobing",
+};
+
+/*
+ * set of presets leaves strobing window constant while varying period to allow
+ * experimentation with mark / space ratios for various workloads
+ */
+static u64 afdo2_presets[AFDO2_NR_PRESETS][AFDO2_NR_PARAM_SUM] = {
+	{ 1000, 100 },
+	{ 1000, 1000 },
+	{ 1000, 5000 },
+	{ 1000, 10000 },
+};
+
+struct cscfg_config_desc afdo2 = {
+	.name = "autofdo2",
+	.description = "Setup ETMs with strobing for autofdo\n"
+	"Supplied presets allow experimentation with mark-space ratio for various loads\n",
+	.nr_feat_refs = ARRAY_SIZE(afdo2_ref_names),
+	.feat_ref_names = afdo2_ref_names,
+	.nr_presets = AFDO2_NR_PRESETS,
+	.nr_total_params = AFDO2_NR_PARAM_SUM,
+	.presets = &afdo2_presets[0][0],
+};
+
+static struct cscfg_feature_desc *sample_feats[] = {
+	NULL
+};
+
+static struct cscfg_config_desc *sample_cfgs[] = {
+	&afdo2,
+	NULL
+};
+
+static struct cscfg_load_owner_info mod_owner = {
+	.type = CSCFG_OWNER_MODULE,
+	.owner_handle = THIS_MODULE,
+};
+
+/* module init and exit - just load and unload configs */
+static int __init cscfg_sample_init(void)
+{
+	return cscfg_load_config_sets(sample_cfgs, sample_feats, &mod_owner);
+}
+
+static void __exit cscfg_sample_exit(void)
+{
+	cscfg_unload_config_sets(&mod_owner);
+}
+
+module_init(cscfg_sample_init);
+module_exit(cscfg_sample_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Mike Leach <mike.leach@linaro.org>");
+MODULE_DESCRIPTION("CoreSight Syscfg Example");
-- 
2.17.1


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[PATCH v2 4/5] coresight: configfs: Allow configfs to activate configuration

[Mike Leach]

Adds configfs attributes to allow a configuration to be enabled for use
when sysfs is used to control CoreSight.

perf retains independent enabling of configurations.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 .../coresight/coresight-etm4x-core.c          |  11 +-
 .../coresight/coresight-syscfg-configfs.c     |  67 ++++++++++
 .../coresight/coresight-syscfg-configfs.h     |   2 +
 .../hwtracing/coresight/coresight-syscfg.c    | 126 ++++++++++++++----
 .../hwtracing/coresight/coresight-syscfg.h    |   8 +-
 5 files changed, 186 insertions(+), 28 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 86a313857b58..bf18128cf5de 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -722,7 +722,16 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
 {
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	struct etm4_enable_arg arg = { };
-	int ret;
+	unsigned long cfg_hash;
+	int ret, preset;
+
+	/* enable any config activated by configfs */
+	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
+	if (cfg_hash) {
+		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
+		if (ret)
+			return ret;
+	}
 
 	spin_lock(&drvdata->spinlock);
 
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
index 345a62f1b728..c388a77a2683 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
@@ -6,6 +6,7 @@
 
 #include <linux/configfs.h>
 
+#include "coresight-config.h"
 #include "coresight-syscfg-configfs.h"
 
 /* create a default ci_type. */
@@ -87,9 +88,75 @@ static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page)
 }
 CONFIGFS_ATTR_RO(cscfg_cfg_, values);
 
+static ssize_t cscfg_cfg_activate_show(struct config_item *item, char *page)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+
+	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->active);
+}
+
+static ssize_t cscfg_cfg_activate_store(struct config_item *item,
+					const char *page, size_t count)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+	int err;
+	bool val;
+
+	err = kstrtobool(page, &val);
+	if (!err)
+		err = cscfg_config_sysfs_activate(fs_config->config_desc, val);
+	if (!err) {
+		fs_config->active = val;
+		if (val)
+			cscfg_config_sysfs_set_preset(fs_config->preset);
+	}
+	return err ? err : count;
+}
+CONFIGFS_ATTR(cscfg_cfg_, activate);
+
+static ssize_t cscfg_cfg_active_preset_show(struct config_item *item, char *page)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+
+	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->preset);
+}
+
+static ssize_t cscfg_cfg_active_preset_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
+							 struct cscfg_fs_config, group);
+	int preset, err;
+
+	err = kstrtoint(page, 0, &preset);
+	if (!err) {
+		/*
+		 * presets start at 1, and go up to max (15),
+		 * but the config may provide fewer.
+		 */
+		if ((preset < 1) || (preset > fs_config->config_desc->nr_presets))
+			err = -EINVAL;
+	}
+
+	if (!err) {
+		/* set new value */
+		fs_config->preset = preset;
+		/* set on system if active */
+		if (fs_config->active)
+			cscfg_config_sysfs_set_preset(fs_config->preset);
+	}
+	return err ? err : count;
+}
+CONFIGFS_ATTR(cscfg_cfg_, active_preset);
+
 static struct configfs_attribute *cscfg_config_view_attrs[] = {
 	&cscfg_cfg_attr_description,
 	&cscfg_cfg_attr_feature_refs,
+	&cscfg_cfg_attr_activate,
+	&cscfg_cfg_attr_active_preset,
 	NULL,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
index ea1e54d29f7f..373d84d43268 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
@@ -15,6 +15,8 @@
 struct cscfg_fs_config {
 	struct cscfg_config_desc *config_desc;
 	struct config_group group;
+	bool active;
+	int preset;
 };
 
 /* container for feature view */
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 4b91d8d9bc37..759c32889efd 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -744,30 +744,20 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
 }
 EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
 
-/**
- * cscfg_activate_config -  Mark a configuration descriptor as active.
- *
- * This will be seen when csdev devices are enabled in the system.
- * Only activated configurations can be enabled on individual devices.
- * Activation protects the configuration from alteration or removal while
- * active.
- *
- * Selection by hash value - generated from the configuration name when it
- * was loaded and added to the cs_etm/configurations file system for selection
- * by perf.
+/*
+ * This activate configuration for either perf or sysfs. Perf can have multiple
+ * active configs, selected per event, sysfs is limited to one.
  *
  * Increments the configuration descriptor active count and the global active
  * count.
  *
  * @cfg_hash: Hash value of the selected configuration name.
  */
-int cscfg_activate_config(unsigned long cfg_hash)
+static int _cscfg_activate_config(unsigned long cfg_hash)
 {
 	struct cscfg_config_desc *config_desc;
 	int err = -EINVAL;
 
-	mutex_lock(&cscfg_mutex);
-
 	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
 		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
 			/* must ensure that config cannot be unloaded in use */
@@ -791,6 +781,101 @@ int cscfg_activate_config(unsigned long cfg_hash)
 			break;
 		}
 	}
+	return err;
+}
+
+static void _cscfg_deactivate_config(unsigned long cfg_hash)
+{
+	struct cscfg_config_desc *config_desc;
+
+	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
+		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
+			atomic_dec(&config_desc->active_cnt);
+			atomic_dec(&cscfg_mgr->sys_active_cnt);
+			cscfg_owner_put(config_desc->load_owner);
+			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
+			break;
+		}
+	}
+}
+
+/*
+ * called from configfs to set/clear the active configuration for use when
+ * using sysfs to control trace.
+ */
+int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool activate)
+{
+	unsigned long cfg_hash;
+	int err = 0;
+
+	mutex_lock(&cscfg_mutex);
+
+	cfg_hash = (unsigned long)config_desc->event_ea->var;
+
+	if (activate) {
+		/* cannot be a current active value to activate this */
+		if (cscfg_mgr->sysfs_active_config) {
+			err = -EBUSY;
+			goto exit_unlock;
+		}
+		err = _cscfg_activate_config(cfg_hash);
+		if (!err)
+			cscfg_mgr->sysfs_active_config = cfg_hash;
+	} else {
+		/* disable if matching current value */
+		if (cscfg_mgr->sysfs_active_config == cfg_hash) {
+			_cscfg_deactivate_config(cfg_hash);
+			cscfg_mgr->sysfs_active_config = 0;
+		} else
+			err = -EINVAL;
+	}
+
+exit_unlock:
+	mutex_unlock(&cscfg_mutex);
+	return err;
+}
+
+/* set the sysfs preset value */
+void cscfg_config_sysfs_set_preset(int preset)
+{
+	mutex_lock(&cscfg_mutex);
+	cscfg_mgr->sysfs_active_preset = preset;
+	mutex_unlock(&cscfg_mutex);
+}
+
+/*
+ * Used by a device to get the config and preset selected as active in configfs,
+ * when using sysfs to control trace.
+ */
+void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
+{
+	mutex_lock(&cscfg_mutex);
+	*preset = cscfg_mgr->sysfs_active_preset;
+	*cfg_hash = cscfg_mgr->sysfs_active_config;
+	mutex_unlock(&cscfg_mutex);
+}
+EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
+
+/**
+ * cscfg_activate_config -  Mark a configuration descriptor as active.
+ *
+ * This will be seen when csdev devices are enabled in the system.
+ * Only activated configurations can be enabled on individual devices.
+ * Activation protects the configuration from alteration or removal while
+ * active.
+ *
+ * Selection by hash value - generated from the configuration name when it
+ * was loaded and added to the cs_etm/configurations file system for selection
+ * by perf.
+ *
+ * @cfg_hash: Hash value of the selected configuration name.
+ */
+int cscfg_activate_config(unsigned long cfg_hash)
+{
+	int err = 0;
+
+	mutex_lock(&cscfg_mutex);
+	err = _cscfg_activate_config(cfg_hash);
 	mutex_unlock(&cscfg_mutex);
 
 	return err;
@@ -806,19 +891,8 @@ EXPORT_SYMBOL_GPL(cscfg_activate_config);
  */
 void cscfg_deactivate_config(unsigned long cfg_hash)
 {
-	struct cscfg_config_desc *config_desc;
-
 	mutex_lock(&cscfg_mutex);
-
-	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
-		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
-			atomic_dec(&config_desc->active_cnt);
-			atomic_dec(&cscfg_mgr->sys_active_cnt);
-			cscfg_owner_put(config_desc->load_owner);
-			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
-			break;
-		}
-	}
+	_cscfg_deactivate_config(cfg_hash);
 	mutex_unlock(&cscfg_mutex);
 }
 EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
index 1da37874f70f..9106ffab4833 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.h
+++ b/drivers/hwtracing/coresight/coresight-syscfg.h
@@ -28,6 +28,8 @@
  * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
  * @sys_active_cnt:	Total number of active config descriptor references.
  * @cfgfs_subsys:	configfs subsystem used to manage configurations.
+ * @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
+ * @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
  */
 struct cscfg_manager {
 	struct device dev;
@@ -37,6 +39,8 @@ struct cscfg_manager {
 	struct list_head load_order_list;
 	atomic_t sys_active_cnt;
 	struct configfs_subsystem cfgfs_subsys;
+	u32 sysfs_active_config;
+	int sysfs_active_preset;
 };
 
 /* get reference to dev in cscfg_manager */
@@ -88,7 +92,8 @@ int cscfg_preload(void *owner_handle);
 const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
 int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
 				int param_idx, u64 value);
-
+int cscfg_config_sysfs_activate(struct cscfg_config_desc *cfg_desc, bool activate);
+void cscfg_config_sysfs_set_preset(int preset);
 
 /* syscfg manager external API */
 int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
@@ -104,5 +109,6 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev);
 int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
 				     unsigned long cfg_hash, int preset);
 void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
+void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset);
 
 #endif /* CORESIGHT_SYSCFG_H */
-- 
2.17.1


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[PATCH v2 5/5] Documentation: coresight: Update coresight configuration docs

[Mike Leach]

Update the CoreSight System Configuration document to cover the
use of loadable modules to add configurations and features
to the system.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 .../trace/coresight/coresight-config.rst      | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst
index a4e3ef295240..911db4da7f99 100644
--- a/Documentation/trace/coresight/coresight-config.rst
+++ b/Documentation/trace/coresight/coresight-config.rst
@@ -242,3 +242,22 @@ A preset to override the current parameter values can also be selected::
 
 When configurations are selected in this way, then the trace sink used is
 automatically selected.
+
+Creating and Loading Custom Configurations
+==========================================
+
+Custom configurations and / or features can be dynamically loaded into the
+system by using a loadable module.
+
+An example of a custom configuration is found in ./samples/coresight.
+
+This creates a new configuration that uses the existing built in
+strobing feature, but provides a different set of presets.
+
+When the module is loaded, then the configuration appears in the configfs
+file system and is selectable in the same way as the built in configuration
+described above.
+
+Configurations can use previously loaded features. The system will ensure
+that it is not possible to unload a feature that is currently in use, by
+enforcing the unload order as the strict reverse of the load order.
-- 
2.17.1


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Re: [PATCH v2 5/5] Documentation: coresight: Update coresight configuration docs

[German Gomez]

Hi Mike,

Sorry if this is the wrong channel to report this, but is the section in
the coresight-config configuration, where it lists "configurations"
under the "/sys/devices/cs_etm/" directory still relevant?

    $ ls /sys/devices/cs_etm
    configurations  format  perf_event_mux_interval_ms  sinks  type
    events  nr_addr_filters  power

I think it may have been removed in a previous patchset [1]. I didn't
see it when trying the coresight-config patches.

    2) Dropped the 'configurations' sub dir in cs_etm perf directories as superfluous

Thanks,
German

[1] https://lore.kernel.org/linux-arm-kernel/20210707133003.5414-1-mike.leach@linaro.org/

On 19/10/2021 20:13, Mike Leach wrote:
> Update the CoreSight System Configuration document to cover the
> use of loadable modules to add configurations and features
> to the system.
>
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
>  .../trace/coresight/coresight-config.rst      | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
>
> diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst
> index a4e3ef295240..911db4da7f99 100644
> --- a/Documentation/trace/coresight/coresight-config.rst
> +++ b/Documentation/trace/coresight/coresight-config.rst
> @@ -242,3 +242,22 @@ A preset to override the current parameter values can also be selected::
>  
>  When configurations are selected in this way, then the trace sink used is
>  automatically selected.
> +
> +Creating and Loading Custom Configurations
> +==========================================
> +
> +Custom configurations and / or features can be dynamically loaded into the
> +system by using a loadable module.
> +
> +An example of a custom configuration is found in ./samples/coresight.
> +
> +This creates a new configuration that uses the existing built in
> +strobing feature, but provides a different set of presets.
> +
> +When the module is loaded, then the configuration appears in the configfs
> +file system and is selectable in the same way as the built in configuration
> +described above.
> +
> +Configurations can use previously loaded features. The system will ensure
> +that it is not possible to unload a feature that is currently in use, by
> +enforcing the unload order as the strict reverse of the load order.

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Re: [PATCH v2 5/5] Documentation: coresight: Update coresight configuration docs

[Mike Leach]

Hi German,


On Wed, 20 Oct 2021 at 11:08, German Gomez <german.gomez@arm.com> wrote:
>
> Hi Mike,
>
> Sorry if this is the wrong channel to report this, but is the section in

This is exactly the right place to report this!

> the coresight-config configuration, where it lists "configurations"
> under the "/sys/devices/cs_etm/" directory still relevant?
>
>     $ ls /sys/devices/cs_etm
>     configurations  format  perf_event_mux_interval_ms  sinks  type
>     events  nr_addr_filters  power
>
> I think it may have been removed in a previous patchset [1]. I didn't
> see it when trying the coresight-config patches.
>
>     2) Dropped the 'configurations' sub dir in cs_etm perf directories as superfluous
>

I think you are correct - I haven't got access to my target to
confirm, but I do remember removing this directory - so the docs do
need updating.
I'll either fix on a respin of this set, or generate a separate patch.

Thanks for spotting this.

Mike


> Thanks,
> German
>
> [1] https://lore.kernel.org/linux-arm-kernel/20210707133003.5414-1-mike.leach@linaro.org/
>
> On 19/10/2021 20:13, Mike Leach wrote:
> > Update the CoreSight System Configuration document to cover the
> > use of loadable modules to add configurations and features
> > to the system.
> >
> > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > ---
> >  .../trace/coresight/coresight-config.rst      | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst
> > index a4e3ef295240..911db4da7f99 100644
> > --- a/Documentation/trace/coresight/coresight-config.rst
> > +++ b/Documentation/trace/coresight/coresight-config.rst
> > @@ -242,3 +242,22 @@ A preset to override the current parameter values can also be selected::
> >
> >  When configurations are selected in this way, then the trace sink used is
> >  automatically selected.
> > +
> > +Creating and Loading Custom Configurations
> > +==========================================
> > +
> > +Custom configurations and / or features can be dynamically loaded into the
> > +system by using a loadable module.
> > +
> > +An example of a custom configuration is found in ./samples/coresight.
> > +
> > +This creates a new configuration that uses the existing built in
> > +strobing feature, but provides a different set of presets.
> > +
> > +When the module is loaded, then the configuration appears in the configfs
> > +file system and is selectable in the same way as the built in configuration
> > +described above.
> > +
> > +Configurations can use previously loaded features. The system will ensure
> > +that it is not possible to unload a feature that is currently in use, by
> > +enforcing the unload order as the strict reverse of the load order.



-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

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Re: [PATCH v2 1/5] coresight: syscfg: Update API to allow dynamic load and unload

[Mathieu Poirier]

Good morning Mike,

On Tue, Oct 19, 2021 at 08:13:47PM +0100, Mike Leach wrote:
> Update the load API to permit the runtime loading and unloading of new
> configurations and features.
> 
> On load, configurations and features are tagged with a "load owner" that
> is used to determine sets that were loaded together in a given API call.
> 
> To unload the API uses the load owner to unload all elements previously
> loaded by that owner.
> 
> The API also records the order in which different owners loaded
> their elements into the system. Later loading configurations can use
> previously loaded features, creating load dependencies. Therefore unload
> is enforced strictly in the reverse order to load.
> 
> A load owner will be an additional loadable module, or a configuration
> created or loaded via configfs.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

I couldn't remember the patchset so I started reviewing it again from scratch.

I didn't find any flaws in the code.  On the flip side I think there is two
things happening here: 1) the addition of the owner concept and 2) the enhancement
of the API to add/remove configurations/features.

Please consider splitting in two different patches.  More comments tomorrow...

Thanks,
Mathieu

> ---
>  .../coresight/coresight-cfg-preload.c         |   9 +-
>  .../hwtracing/coresight/coresight-config.h    |   9 +-
>  .../coresight/coresight-syscfg-configfs.c     |  20 +++
>  .../coresight/coresight-syscfg-configfs.h     |   2 +
>  .../hwtracing/coresight/coresight-syscfg.c    | 154 +++++++++++++++++-
>  .../hwtracing/coresight/coresight-syscfg.h    |  30 +++-
>  6 files changed, 216 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cfg-preload.c b/drivers/hwtracing/coresight/coresight-cfg-preload.c
> index 751af3710d56..e237a4edfa09 100644
> --- a/drivers/hwtracing/coresight/coresight-cfg-preload.c
> +++ b/drivers/hwtracing/coresight/coresight-cfg-preload.c
> @@ -24,8 +24,13 @@ static struct cscfg_config_desc *preload_cfgs[] = {
>  	NULL
>  };
>  
> +static struct cscfg_load_owner_info preload_owner = {
> +	.type = CSCFG_OWNER_PRELOAD,
> +};
> +
>  /* preload called on initialisation */
> -int cscfg_preload(void)
> +int cscfg_preload(void *owner_handle)
>  {
> -	return cscfg_load_config_sets(preload_cfgs, preload_feats);
> +	preload_owner.owner_handle = owner_handle;
> +	return cscfg_load_config_sets(preload_cfgs, preload_feats, &preload_owner);
>  }
> diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
> index 25eb6c632692..9bd44b940add 100644
> --- a/drivers/hwtracing/coresight/coresight-config.h
> +++ b/drivers/hwtracing/coresight/coresight-config.h
> @@ -97,6 +97,8 @@ struct cscfg_regval_desc {
>   * @params_desc: array of parameters used.
>   * @nr_regs:	 number of registers used.
>   * @regs_desc:	 array of registers used.
> + * @load_owner:	 handle to load owner for dynamic load and unload of features.
> + * @fs_group:	 reference to configfs group for dynamic unload.
>   */
>  struct cscfg_feature_desc {
>  	const char *name;
> @@ -107,6 +109,8 @@ struct cscfg_feature_desc {
>  	struct cscfg_parameter_desc *params_desc;
>  	int nr_regs;
>  	struct cscfg_regval_desc *regs_desc;
> +	void *load_owner;
> +	struct config_group *fs_group;
>  };
>  
>  /**
> @@ -128,7 +132,8 @@ struct cscfg_feature_desc {
>   * @presets:		Array of preset values.
>   * @event_ea:		Extended attribute for perf event value
>   * @active_cnt:		ref count for activate on this configuration.
> - *
> + * @load_owner:		handle to load owner for dynamic load and unload of configs.
> + * @fs_group:		reference to configfs group for dynamic unload.
>   */
>  struct cscfg_config_desc {
>  	const char *name;
> @@ -141,6 +146,8 @@ struct cscfg_config_desc {
>  	const u64 *presets; /* nr_presets * nr_total_params */
>  	struct dev_ext_attribute *event_ea;
>  	atomic_t active_cnt;
> +	void *load_owner;
> +	struct config_group *fs_group;
>  };
>  
>  /**
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> index c547816b9000..345a62f1b728 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> @@ -334,9 +334,19 @@ int cscfg_configfs_add_config(struct cscfg_config_desc *config_desc)
>  	if (IS_ERR(new_group))
>  		return PTR_ERR(new_group);
>  	err =  configfs_register_group(&cscfg_configs_grp, new_group);
> +	if (!err)
> +		config_desc->fs_group = new_group;
>  	return err;
>  }
>  
> +void cscfg_configfs_del_config(struct cscfg_config_desc *config_desc)
> +{
> +	if (config_desc->fs_group) {
> +		configfs_unregister_group(config_desc->fs_group);
> +		config_desc->fs_group = NULL;
> +	}
> +}
> +
>  static struct config_item_type cscfg_features_type = {
>  	.ct_owner = THIS_MODULE,
>  };
> @@ -358,9 +368,19 @@ int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc)
>  	if (IS_ERR(new_group))
>  		return PTR_ERR(new_group);
>  	err =  configfs_register_group(&cscfg_features_grp, new_group);
> +	if (!err)
> +		feat_desc->fs_group = new_group;
>  	return err;
>  }
>  
> +void cscfg_configfs_del_feature(struct cscfg_feature_desc *feat_desc)
> +{
> +	if (feat_desc->fs_group) {
> +		configfs_unregister_group(feat_desc->fs_group);
> +		feat_desc->fs_group = NULL;
> +	}
> +}
> +
>  int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr)
>  {
>  	struct configfs_subsystem *subsys;
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> index 7d6ffe35ca4c..ea1e54d29f7f 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> @@ -41,5 +41,7 @@ int cscfg_configfs_init(struct cscfg_manager *cscfg_mgr);
>  void cscfg_configfs_release(struct cscfg_manager *cscfg_mgr);
>  int cscfg_configfs_add_config(struct cscfg_config_desc *config_desc);
>  int cscfg_configfs_add_feature(struct cscfg_feature_desc *feat_desc);
> +void cscfg_configfs_del_config(struct cscfg_config_desc *config_desc);
> +void cscfg_configfs_del_feature(struct cscfg_feature_desc *feat_desc);
>  
>  #endif /* CORESIGHT_SYSCFG_CONFIGFS_H */
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index fc0760f55c53..9bb0b0913a9a 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -249,6 +249,13 @@ static int cscfg_check_feat_for_cfg(struct cscfg_config_desc *config_desc)
>  static int cscfg_load_feat(struct cscfg_feature_desc *feat_desc)
>  {
>  	int err;
> +	struct cscfg_feature_desc *feat_desc_exist;
> +
> +	/* new feature must have unique name */
> +	list_for_each_entry(feat_desc_exist, &cscfg_mgr->feat_desc_list, item) {
> +		if (!strcmp(feat_desc_exist->name, feat_desc->name))
> +			return -EEXIST;
> +	}
>  
>  	/* add feature to any matching registered devices */
>  	err = cscfg_add_feat_to_csdevs(feat_desc);
> @@ -266,6 +273,13 @@ static int cscfg_load_feat(struct cscfg_feature_desc *feat_desc)
>  static int cscfg_load_config(struct cscfg_config_desc *config_desc)
>  {
>  	int err;
> +	struct cscfg_config_desc *config_desc_exist;
> +
> +	/* new configuration must have a unique name */
> +	list_for_each_entry(config_desc_exist, &cscfg_mgr->config_desc_list, item) {
> +		if (!strcmp(config_desc_exist->name, config_desc->name))
> +			return -EEXIST;
> +	}
>  
>  	/* validate features are present */
>  	err = cscfg_check_feat_for_cfg(config_desc);
> @@ -353,6 +367,72 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>  	return err;
>  }
>  
> +static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, void *load_owner)
> +{
> +	struct cscfg_config_csdev *config_csdev, *tmp;
> +
> +	if (list_empty(&csdev->config_csdev_list))
> +		return;
> +
> +	list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) {
> +		if (config_csdev->config_desc->load_owner == load_owner)
> +			list_del(&config_csdev->node);
> +	}
> +}
> +
> +static void cscfg_remove_owned_csdev_features(struct coresight_device *csdev, void *load_owner)
> +{
> +	struct cscfg_feature_csdev *feat_csdev, *tmp;
> +
> +	if (list_empty(&csdev->feature_csdev_list))
> +		return;
> +
> +	list_for_each_entry_safe(feat_csdev, tmp, &csdev->feature_csdev_list, node) {
> +		if (feat_csdev->feat_desc->load_owner == load_owner)
> +			list_del(&feat_csdev->node);
> +	}
> +}
> +
> +/*
> + * removal is relatively easy - just remove from all lists, anything that
> + * matches the owner. Memory for the descriptors will be managed by the owner,
> + * memory for the csdev items is devm_ allocated with the individual csdev
> + * devices.
> + */
> +static void cscfg_unload_owned_cfgs_feats(void *load_owner)
> +{
> +	struct cscfg_config_desc *config_desc, *cfg_tmp;
> +	struct cscfg_feature_desc *feat_desc, *feat_tmp;
> +	struct cscfg_registered_csdev *csdev_item;
> +
> +	/* remove from each csdev instance feature and config lists */
> +	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
> +		/*
> +		 * for each csdev, check the loaded lists and remove if
> +		 * referenced descriptor is owned
> +		 */
> +		cscfg_remove_owned_csdev_configs(csdev_item->csdev, load_owner);
> +		cscfg_remove_owned_csdev_features(csdev_item->csdev, load_owner);
> +	}
> +
> +	/* remove from the config descriptor lists */
> +	list_for_each_entry_safe(config_desc, cfg_tmp, &cscfg_mgr->config_desc_list, item) {
> +		if (config_desc->load_owner == load_owner) {
> +			cscfg_configfs_del_config(config_desc);
> +			etm_perf_del_symlink_cscfg(config_desc);
> +			list_del(&config_desc->item);
> +		}
> +	}
> +
> +	/* remove from the feature descriptor lists */
> +	list_for_each_entry_safe(feat_desc, feat_tmp, &cscfg_mgr->feat_desc_list, item) {
> +		if (feat_desc->load_owner == load_owner) {
> +			cscfg_configfs_del_feature(feat_desc);
> +			list_del(&feat_desc->item);
> +		}
> +	}
> +}
> +
>  /**
>   * cscfg_load_config_sets - API function to load feature and config sets.
>   *
> @@ -360,13 +440,22 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>   * descriptors and load into the system.
>   * Features are loaded first to ensure configuration dependencies can be met.
>   *
> + * To facilitate dynamic loading and unloading, features and configurations
> + * have a "load_owner", to allow later unload by the same owner. An owner may
> + * be a loadable module or configuration dynamically created via configfs.
> + * As later loaded configurations can use earlier loaded features, creating load
> + * dependencies, a load order list is maintained. Unload is strictly in the
> + * reverse order to load.
> + *
>   * @config_descs: 0 terminated array of configuration descriptors.
>   * @feat_descs:   0 terminated array of feature descriptors.
> + * @owner_info:	  Information on the owner of this set.
>   */
>  int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
> -			   struct cscfg_feature_desc **feat_descs)
> +			   struct cscfg_feature_desc **feat_descs,
> +			   struct cscfg_load_owner_info *owner_info)
>  {
> -	int err, i = 0;
> +	int err = 0, i = 0;
>  
>  	mutex_lock(&cscfg_mutex);
>  
> @@ -379,8 +468,10 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
>  			if (err) {
>  				pr_err("coresight-syscfg: Failed to load feature %s\n",
>  				       feat_descs[i]->name);
> +				cscfg_unload_owned_cfgs_feats(owner_info);
>  				goto exit_unlock;
>  			}
> +			feat_descs[i]->load_owner = owner_info;
>  			i++;
>  		}
>  	}
> @@ -395,18 +486,74 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs,
>  			if (err) {
>  				pr_err("coresight-syscfg: Failed to load configuration %s\n",
>  				       config_descs[i]->name);
> +				cscfg_unload_owned_cfgs_feats(owner_info);
>  				goto exit_unlock;
>  			}
> +			config_descs[i]->load_owner = owner_info;
>  			i++;
>  		}
>  	}
>  
> +	/* add the load owner to the load order list */
> +	list_add_tail(&owner_info->item, &cscfg_mgr->load_order_list);
> +
>  exit_unlock:
>  	mutex_unlock(&cscfg_mutex);
>  	return err;
>  }
>  EXPORT_SYMBOL_GPL(cscfg_load_config_sets);
>  
> +/**
> + * cscfg_unload_config_sets - unload a set of configurations by owner.
> + *
> + * Dynamic unload of configuration and feature sets is done on the basis of
> + * the load owner of that set. Later loaded configurations can depend on
> + * features loaded earlier.
> + *
> + * Therefore, unload is only possible if:-
> + * 1) no configurations are active.
> + * 2) the set being unloaded was the last to be loaded to maintain dependencies.
> + *
> + * @owner_info:	Information on owner for set being unloaded.
> + */
> +int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info)
> +{
> +	int err = 0;
> +	struct cscfg_load_owner_info *load_list_item = NULL;
> +
> +	mutex_lock(&cscfg_mutex);
> +
> +	/* cannot unload if anything is active */
> +	if (atomic_read(&cscfg_mgr->sys_active_cnt)) {
> +		err = -EBUSY;
> +		goto exit_unlock;
> +	}
> +
> +	/* cannot unload if not last loaded in load order */
> +	if (!list_empty(&cscfg_mgr->load_order_list)) {
> +		load_list_item = list_last_entry(&cscfg_mgr->load_order_list,
> +						 struct cscfg_load_owner_info, item);
> +		if (load_list_item != owner_info)
> +			load_list_item = NULL;
> +	}
> +
> +	if (!load_list_item) {
> +		err = -EINVAL;
> +		goto exit_unlock;
> +	}
> +
> +	/* unload all belonging to load_owner */
> +	cscfg_unload_owned_cfgs_feats(owner_info);
> +
> +	/* remove from load order list */
> +	list_del(&load_list_item->item);
> +
> +exit_unlock:
> +	mutex_unlock(&cscfg_mutex);
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(cscfg_unload_config_sets);
> +
>  /* Handle coresight device registration and add configs and features to devices */
>  
>  /* iterate through config lists and load matching configs to device */
> @@ -826,10 +973,11 @@ int __init cscfg_init(void)
>  	INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
>  	INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
>  	INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
> +	INIT_LIST_HEAD(&cscfg_mgr->load_order_list);
>  	atomic_set(&cscfg_mgr->sys_active_cnt, 0);
>  
>  	/* preload built-in configurations */
> -	err = cscfg_preload();
> +	err = cscfg_preload(THIS_MODULE);
>  	if (err)
>  		goto exit_err;
>  
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
> index 8d018efd6ead..e2b2bdab31aa 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.h
> @@ -25,6 +25,7 @@
>   * @csdev_desc_list:	List of coresight devices registered with the configuration manager.
>   * @feat_desc_list:	List of feature descriptors to load into registered devices.
>   * @config_desc_list:	List of system configuration descriptors to load into registered devices.
> + * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
>   * @sys_active_cnt:	Total number of active config descriptor references.
>   * @cfgfs_subsys:	configfs subsystem used to manage configurations.
>   */
> @@ -33,6 +34,7 @@ struct cscfg_manager {
>  	struct list_head csdev_desc_list;
>  	struct list_head feat_desc_list;
>  	struct list_head config_desc_list;
> +	struct list_head load_order_list;
>  	atomic_t sys_active_cnt;
>  	struct configfs_subsystem cfgfs_subsys;
>  };
> @@ -56,10 +58,32 @@ struct cscfg_registered_csdev {
>  	struct list_head item;
>  };
>  
> +/* owner types for loading and unloading of config and feature sets */
> +enum cscfg_load_owner_type {
> +	CSCFG_OWNER_PRELOAD,
> +};
> +
> +/**
> + * Load item - item to add to the load order list allowing dynamic load and
> + *             unload of configurations and features. Caller loading a config
> + *	       set provides a context handle for unload. API ensures that
> + *	       items unloaded strictly in reverse order from load to ensure
> + *	       dependencies are respected.
> + *
> + * @item:		list entry for load order list.
> + * @type:		type of owner - allows interpretation of owner_handle.
> + * @owner_handle:	load context - handle for owner of loaded configs.
> + */
> +struct cscfg_load_owner_info {
> +	struct list_head item;
> +	int type;
> +	void *owner_handle;
> +};
> +
>  /* internal core operations for cscfg */
>  int __init cscfg_init(void);
>  void cscfg_exit(void);
> -int cscfg_preload(void);
> +int cscfg_preload(void *owner_handle);
>  const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
>  int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>  				int param_idx, u64 value);
> @@ -67,7 +91,9 @@ int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>  
>  /* syscfg manager external API */
>  int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
> -			   struct cscfg_feature_desc **feat_descs);
> +			   struct cscfg_feature_desc **feat_descs,
> +			   struct cscfg_load_owner_info *owner_info);
> +int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info);
>  int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags,
>  			 struct cscfg_csdev_feat_ops *ops);
>  void cscfg_unregister_csdev(struct coresight_device *csdev);
> -- 
> 2.17.1
> 

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Re: [PATCH v2 4/5] coresight: configfs: Allow configfs to activate configuration

[Mathieu Poirier]

Good day Mike,

On Tue, Oct 19, 2021 at 08:13:50PM +0100, Mike Leach wrote:
> Adds configfs attributes to allow a configuration to be enabled for use
> when sysfs is used to control CoreSight.
> 
> perf retains independent enabling of configurations.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> ---
>  .../coresight/coresight-etm4x-core.c          |  11 +-
>  .../coresight/coresight-syscfg-configfs.c     |  67 ++++++++++
>  .../coresight/coresight-syscfg-configfs.h     |   2 +
>  .../hwtracing/coresight/coresight-syscfg.c    | 126 ++++++++++++++----
>  .../hwtracing/coresight/coresight-syscfg.h    |   8 +-
>  5 files changed, 186 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> index 86a313857b58..bf18128cf5de 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
> @@ -722,7 +722,16 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
>  {
>  	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>  	struct etm4_enable_arg arg = { };
> -	int ret;
> +	unsigned long cfg_hash;
> +	int ret, preset;
> +
> +	/* enable any config activated by configfs */
> +	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
> +	if (cfg_hash) {
> +		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	spin_lock(&drvdata->spinlock);
>  
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> index 345a62f1b728..c388a77a2683 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c
> @@ -6,6 +6,7 @@
>  
>  #include <linux/configfs.h>
>  
> +#include "coresight-config.h"
>  #include "coresight-syscfg-configfs.h"
>  
>  /* create a default ci_type. */
> @@ -87,9 +88,75 @@ static ssize_t cscfg_cfg_values_show(struct config_item *item, char *page)
>  }
>  CONFIGFS_ATTR_RO(cscfg_cfg_, values);
>  
> +static ssize_t cscfg_cfg_activate_show(struct config_item *item, char *page)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +
> +	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->active);
> +}
> +
> +static ssize_t cscfg_cfg_activate_store(struct config_item *item,
> +					const char *page, size_t count)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +	int err;
> +	bool val;
> +
> +	err = kstrtobool(page, &val);
> +	if (!err)
> +		err = cscfg_config_sysfs_activate(fs_config->config_desc, val);
> +	if (!err) {
> +		fs_config->active = val;
> +		if (val)
> +			cscfg_config_sysfs_set_preset(fs_config->preset);
> +	}
> +	return err ? err : count;
> +}
> +CONFIGFS_ATTR(cscfg_cfg_, activate);

I would call this "enable" to follow what is already done for coresight in
sysfs.

> +
> +static ssize_t cscfg_cfg_active_preset_show(struct config_item *item, char *page)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +
> +	return scnprintf(page, PAGE_SIZE, "%d\n", fs_config->preset);
> +}
> +
> +static ssize_t cscfg_cfg_active_preset_store(struct config_item *item,
> +					     const char *page, size_t count)
> +{
> +	struct cscfg_fs_config *fs_config = container_of(to_config_group(item),
> +							 struct cscfg_fs_config, group);
> +	int preset, err;
> +
> +	err = kstrtoint(page, 0, &preset);
> +	if (!err) {
> +		/*
> +		 * presets start at 1, and go up to max (15),
> +		 * but the config may provide fewer.
> +		 */
> +		if ((preset < 1) || (preset > fs_config->config_desc->nr_presets))
> +			err = -EINVAL;
> +	}
> +
> +	if (!err) {
> +		/* set new value */
> +		fs_config->preset = preset;
> +		/* set on system if active */
> +		if (fs_config->active)
> +			cscfg_config_sysfs_set_preset(fs_config->preset);
> +	}
> +	return err ? err : count;
> +}
> +CONFIGFS_ATTR(cscfg_cfg_, active_preset);

And I would call this "preset" since this is what is used on the perf cmd line.

Please add a new "Using Configurations from configfs" section in [1] to
show how "enable" and "preset" should be used.

With that:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>


[1]. Documentation/trace/coresight/coresight-config.rst

> +
>  static struct configfs_attribute *cscfg_config_view_attrs[] = {
>  	&cscfg_cfg_attr_description,
>  	&cscfg_cfg_attr_feature_refs,
> +	&cscfg_cfg_attr_activate,
> +	&cscfg_cfg_attr_active_preset,
>  	NULL,
>  };
>  
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> index ea1e54d29f7f..373d84d43268 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.h
> @@ -15,6 +15,8 @@
>  struct cscfg_fs_config {
>  	struct cscfg_config_desc *config_desc;
>  	struct config_group group;
> +	bool active;
> +	int preset;
>  };
>  
>  /* container for feature view */
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> index 4b91d8d9bc37..759c32889efd 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> @@ -744,30 +744,20 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev)
>  }
>  EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
>  
> -/**
> - * cscfg_activate_config -  Mark a configuration descriptor as active.
> - *
> - * This will be seen when csdev devices are enabled in the system.
> - * Only activated configurations can be enabled on individual devices.
> - * Activation protects the configuration from alteration or removal while
> - * active.
> - *
> - * Selection by hash value - generated from the configuration name when it
> - * was loaded and added to the cs_etm/configurations file system for selection
> - * by perf.
> +/*
> + * This activate configuration for either perf or sysfs. Perf can have multiple
> + * active configs, selected per event, sysfs is limited to one.
>   *
>   * Increments the configuration descriptor active count and the global active
>   * count.
>   *
>   * @cfg_hash: Hash value of the selected configuration name.
>   */
> -int cscfg_activate_config(unsigned long cfg_hash)
> +static int _cscfg_activate_config(unsigned long cfg_hash)
>  {
>  	struct cscfg_config_desc *config_desc;
>  	int err = -EINVAL;
>  
> -	mutex_lock(&cscfg_mutex);
> -
>  	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
>  		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
>  			/* must ensure that config cannot be unloaded in use */
> @@ -791,6 +781,101 @@ int cscfg_activate_config(unsigned long cfg_hash)
>  			break;
>  		}
>  	}
> +	return err;
> +}
> +
> +static void _cscfg_deactivate_config(unsigned long cfg_hash)
> +{
> +	struct cscfg_config_desc *config_desc;
> +
> +	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> +		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> +			atomic_dec(&config_desc->active_cnt);
> +			atomic_dec(&cscfg_mgr->sys_active_cnt);
> +			cscfg_owner_put(config_desc->load_owner);
> +			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
> +			break;
> +		}
> +	}
> +}
> +
> +/*
> + * called from configfs to set/clear the active configuration for use when
> + * using sysfs to control trace.
> + */
> +int cscfg_config_sysfs_activate(struct cscfg_config_desc *config_desc, bool activate)
> +{
> +	unsigned long cfg_hash;
> +	int err = 0;
> +
> +	mutex_lock(&cscfg_mutex);
> +
> +	cfg_hash = (unsigned long)config_desc->event_ea->var;
> +
> +	if (activate) {
> +		/* cannot be a current active value to activate this */
> +		if (cscfg_mgr->sysfs_active_config) {
> +			err = -EBUSY;
> +			goto exit_unlock;
> +		}
> +		err = _cscfg_activate_config(cfg_hash);
> +		if (!err)
> +			cscfg_mgr->sysfs_active_config = cfg_hash;
> +	} else {
> +		/* disable if matching current value */
> +		if (cscfg_mgr->sysfs_active_config == cfg_hash) {
> +			_cscfg_deactivate_config(cfg_hash);
> +			cscfg_mgr->sysfs_active_config = 0;
> +		} else
> +			err = -EINVAL;
> +	}
> +
> +exit_unlock:
> +	mutex_unlock(&cscfg_mutex);
> +	return err;
> +}
> +
> +/* set the sysfs preset value */
> +void cscfg_config_sysfs_set_preset(int preset)
> +{
> +	mutex_lock(&cscfg_mutex);
> +	cscfg_mgr->sysfs_active_preset = preset;
> +	mutex_unlock(&cscfg_mutex);
> +}
> +
> +/*
> + * Used by a device to get the config and preset selected as active in configfs,
> + * when using sysfs to control trace.
> + */
> +void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset)
> +{
> +	mutex_lock(&cscfg_mutex);
> +	*preset = cscfg_mgr->sysfs_active_preset;
> +	*cfg_hash = cscfg_mgr->sysfs_active_config;
> +	mutex_unlock(&cscfg_mutex);
> +}
> +EXPORT_SYMBOL_GPL(cscfg_config_sysfs_get_active_cfg);
> +
> +/**
> + * cscfg_activate_config -  Mark a configuration descriptor as active.
> + *
> + * This will be seen when csdev devices are enabled in the system.
> + * Only activated configurations can be enabled on individual devices.
> + * Activation protects the configuration from alteration or removal while
> + * active.
> + *
> + * Selection by hash value - generated from the configuration name when it
> + * was loaded and added to the cs_etm/configurations file system for selection
> + * by perf.
> + *
> + * @cfg_hash: Hash value of the selected configuration name.
> + */
> +int cscfg_activate_config(unsigned long cfg_hash)
> +{
> +	int err = 0;
> +
> +	mutex_lock(&cscfg_mutex);
> +	err = _cscfg_activate_config(cfg_hash);
>  	mutex_unlock(&cscfg_mutex);
>  
>  	return err;
> @@ -806,19 +891,8 @@ EXPORT_SYMBOL_GPL(cscfg_activate_config);
>   */
>  void cscfg_deactivate_config(unsigned long cfg_hash)
>  {
> -	struct cscfg_config_desc *config_desc;
> -
>  	mutex_lock(&cscfg_mutex);
> -
> -	list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> -		if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> -			atomic_dec(&config_desc->active_cnt);
> -			atomic_dec(&cscfg_mgr->sys_active_cnt);
> -			cscfg_owner_put(config_desc->load_owner);
> -			dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
> -			break;
> -		}
> -	}
> +	_cscfg_deactivate_config(cfg_hash);
>  	mutex_unlock(&cscfg_mutex);
>  }
>  EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
> diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
> index 1da37874f70f..9106ffab4833 100644
> --- a/drivers/hwtracing/coresight/coresight-syscfg.h
> +++ b/drivers/hwtracing/coresight/coresight-syscfg.h
> @@ -28,6 +28,8 @@
>   * @load_order_list:    Ordered list of owners for dynamically loaded configurations.
>   * @sys_active_cnt:	Total number of active config descriptor references.
>   * @cfgfs_subsys:	configfs subsystem used to manage configurations.
> + * @sysfs_active_config:Active config hash used if CoreSight controlled from sysfs.
> + * @sysfs_active_preset:Active preset index used if CoreSight controlled from sysfs.
>   */
>  struct cscfg_manager {
>  	struct device dev;
> @@ -37,6 +39,8 @@ struct cscfg_manager {
>  	struct list_head load_order_list;
>  	atomic_t sys_active_cnt;
>  	struct configfs_subsystem cfgfs_subsys;
> +	u32 sysfs_active_config;
> +	int sysfs_active_preset;
>  };
>  
>  /* get reference to dev in cscfg_manager */
> @@ -88,7 +92,8 @@ int cscfg_preload(void *owner_handle);
>  const struct cscfg_feature_desc *cscfg_get_named_feat_desc(const char *name);
>  int cscfg_update_feat_param_val(struct cscfg_feature_desc *feat_desc,
>  				int param_idx, u64 value);
> -
> +int cscfg_config_sysfs_activate(struct cscfg_config_desc *cfg_desc, bool activate);
> +void cscfg_config_sysfs_set_preset(int preset);
>  
>  /* syscfg manager external API */
>  int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
> @@ -104,5 +109,6 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev);
>  int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
>  				     unsigned long cfg_hash, int preset);
>  void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
> +void cscfg_config_sysfs_get_active_cfg(unsigned long *cfg_hash, int *preset);
>  
>  #endif /* CORESIGHT_SYSCFG_H */
> -- 
> 2.17.1
> 

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Re: [PATCH v2 0/5] coresight: syscfg: dynamic load

[Mathieu Poirier]

On Tue, Oct 19, 2021 at 08:13:46PM +0100, Mike Leach wrote:
> 1) API updated to allow dynamic load and unload of configurations and
> features. Dependency management between loaded sets is added.
> 
> 2) New configuration and feature sets can be added using a loadable module.
> An example in /samples/coresight is provided to demonstrate this.
> 
> 3) configfs can be used to activate a configuration which will then be used
> when controlling tracing using sysfs.
> 
> Applies and tested on coresight/next - which is 5.15-rc1

I am done reviewing this set.  Other than the minor comments for patches 1 and 4
I think it is ready.  I would like to merge this set before reviewing the rest of
your work [1].  

Thanks,
Mathieu

[1]. "coresight: syscfg: Extend configfs for config load"

> 
> 
> Changes since v1:
> 
> a) Original set split to divide related changes into smaller sets.
> Removed RFC flag.
> 
> b) Revised config activation for sysfs to simplify common function.
> (patch 4). 
> 
> c) Minor changes requested by Mathieu added.
> 
> Mike Leach (5):
>   coresight: syscfg: Update API to allow dynamic load and unload
>   coresight: syscfg: Update load API for config loadable modules
>   coresight: syscfg: Example CoreSight configuration loadable module
>   coresight: configfs: Allow configfs to activate configuration
>   Documentation: coresight: Update coresight configuration docs
> 
>  .../trace/coresight/coresight-config.rst      |  19 ++
>  MAINTAINERS                                   |   1 +
>  .../coresight/coresight-cfg-preload.c         |   9 +-
>  .../hwtracing/coresight/coresight-config.h    |   9 +-
>  .../coresight/coresight-etm4x-core.c          |  11 +-
>  .../coresight/coresight-syscfg-configfs.c     |  87 +++++
>  .../coresight/coresight-syscfg-configfs.h     |   4 +
>  .../hwtracing/coresight/coresight-syscfg.c    | 315 ++++++++++++++++--
>  .../hwtracing/coresight/coresight-syscfg.h    |  39 ++-
>  samples/Kconfig                               |   9 +
>  samples/Makefile                              |   1 +
>  samples/coresight/Makefile                    |   4 +
>  samples/coresight/coresight-cfg-sample.c      |  73 ++++
>  13 files changed, 546 insertions(+), 35 deletions(-)
>  create mode 100644 samples/coresight/Makefile
>  create mode 100644 samples/coresight/coresight-cfg-sample.c
> 
> -- 
> 2.17.1
> 

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Re: [PATCH v2 0/5] coresight: syscfg: dynamic load

[Mike Leach]

Hi Mathieu,

On Thu, 11 Nov 2021 at 17:35, Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> On Tue, Oct 19, 2021 at 08:13:46PM +0100, Mike Leach wrote:
> > 1) API updated to allow dynamic load and unload of configurations and
> > features. Dependency management between loaded sets is added.
> >
> > 2) New configuration and feature sets can be added using a loadable module.
> > An example in /samples/coresight is provided to demonstrate this.
> >
> > 3) configfs can be used to activate a configuration which will then be used
> > when controlling tracing using sysfs.
> >
> > Applies and tested on coresight/next - which is 5.15-rc1
>
> I am done reviewing this set.  Other than the minor comments for patches 1 and 4
> I think it is ready.  I would like to merge this set before reviewing the rest of
> your work [1].
>
> Thanks,
> Mathieu
>

Thanks for the review. I'll update patches 1 & 4 as per you requests -
and add the docs too.

Will rebase onto the lastest coresight next.

Regards

Mike




> [1]. "coresight: syscfg: Extend configfs for config load"
>
> >
> >
> > Changes since v1:
> >
> > a) Original set split to divide related changes into smaller sets.
> > Removed RFC flag.
> >
> > b) Revised config activation for sysfs to simplify common function.
> > (patch 4).
> >
> > c) Minor changes requested by Mathieu added.
> >
> > Mike Leach (5):
> >   coresight: syscfg: Update API to allow dynamic load and unload
> >   coresight: syscfg: Update load API for config loadable modules
> >   coresight: syscfg: Example CoreSight configuration loadable module
> >   coresight: configfs: Allow configfs to activate configuration
> >   Documentation: coresight: Update coresight configuration docs
> >
> >  .../trace/coresight/coresight-config.rst      |  19 ++
> >  MAINTAINERS                                   |   1 +
> >  .../coresight/coresight-cfg-preload.c         |   9 +-
> >  .../hwtracing/coresight/coresight-config.h    |   9 +-
> >  .../coresight/coresight-etm4x-core.c          |  11 +-
> >  .../coresight/coresight-syscfg-configfs.c     |  87 +++++
> >  .../coresight/coresight-syscfg-configfs.h     |   4 +
> >  .../hwtracing/coresight/coresight-syscfg.c    | 315 ++++++++++++++++--
> >  .../hwtracing/coresight/coresight-syscfg.h    |  39 ++-
> >  samples/Kconfig                               |   9 +
> >  samples/Makefile                              |   1 +
> >  samples/coresight/Makefile                    |   4 +
> >  samples/coresight/coresight-cfg-sample.c      |  73 ++++
> >  13 files changed, 546 insertions(+), 35 deletions(-)
> >  create mode 100644 samples/coresight/Makefile
> >  create mode 100644 samples/coresight/coresight-cfg-sample.c
> >
> > --
> > 2.17.1
> >



--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK

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