Update the existing load API to introduce a "load owner" concept.

This allows the tracking of the loaded configurations and features against the loading owner type, to allow later unload according to owner.

A list of loaded configurations by owner is created.

The load owner infrastructure will be used in following patches to implement dynanic load and unload, alongside dependency tracking.

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 | 5 +++- .../hwtracing/coresight/coresight-syscfg.c | 21 ++++++++++++-- .../hwtracing/coresight/coresight-syscfg.h | 29 +++++++++++++++++-- 4 files changed, 56 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..6e0d43901d66 100644 --- a/drivers/hwtracing/coresight/coresight-config.h +++ b/drivers/hwtracing/coresight/coresight-config.h @@ -97,6 +97,7 @@ 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. */ struct cscfg_feature_desc { const char *name; @@ -107,6 +108,7 @@ struct cscfg_feature_desc { struct cscfg_parameter_desc *params_desc; int nr_regs; struct cscfg_regval_desc *regs_desc; + void *load_owner; };

/** @@ -128,7 +130,7 @@ 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. */ struct cscfg_config_desc { const char *name; @@ -141,6 +143,7 @@ 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; };

/** diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 43054568430f..021f50949d7b 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -361,13 +361,22 @@ 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);

@@ -382,6 +391,7 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs, feat_descs[i]->name); goto exit_unlock; } + feat_descs[i]->load_owner = owner_info; i++; } } @@ -398,10 +408,14 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs, config_descs[i]->name); 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; @@ -827,10 +841,11 @@ 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..08067e89edcf 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 +91,8 @@ 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_register_csdev(struct coresight_device *csdev, u32 match_flags, struct cscfg_csdev_feat_ops *ops); void cscfg_unregister_csdev(struct coresight_device *csdev);

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 8bff7da1aab2..678ee8250d85 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -368,6 +368,26 @@ 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; @@ -497,6 +517,14 @@ 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); @@ -547,7 +575,11 @@ 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); @@ -739,6 +771,10 @@ 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 @@ -779,6 +815,7 @@ 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, };

/**

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 Reviewed-by: Mathieu Poirier mathieu.poirier@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..433ede94dd63 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_enable_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_enable_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_, enable); + +static ssize_t cscfg_cfg_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_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_, preset); + static struct configfs_attribute *cscfg_config_view_attrs[] = { &cscfg_cfg_attr_description, &cscfg_cfg_attr_feature_refs, + &cscfg_cfg_attr_enable, + &cscfg_cfg_attr_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 678ee8250d85..098fc34c4829 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -745,30 +745,20 @@ 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 */ @@ -792,6 +782,101 @@ 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; @@ -807,19 +892,8 @@ 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 */

On Wed, Nov 24, 2021 at 08:00:36PM +0000, Mike Leach wrote:

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 7a2345ce8521..85242fdd3b8c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1890,6 +1890,7 @@ 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 bec3528aa2de..fe8b56d576ce 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -232,6 +232,15 @@ 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 config HAVE_SAMPLE_FTRACE_DIRECT diff --git a/samples/Makefile b/samples/Makefile index b7b98307c2b4..c148ada64beb 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -32,3 +32,4 @@ 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",

Checkpatch is complaining the above should be "static const char * const ..." I can't remember if we talked about this before - did we?

Do you want me to make the modification?

HI Mathieu,

On Fri, 26 Nov 2021 at 18:26, Mathieu Poirier mathieu.poirier@linaro.org wrote:

On Wed, Nov 24, 2021 at 08:00:38PM +0000, 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 | 62 ++++++++++++++++++- 1 file changed, 59 insertions(+), 3 deletions(-)

diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst index 6ed13398ca2c..6d5ffa6f7347 100644 --- a/Documentation/trace/coresight/coresight-config.rst +++ b/Documentation/trace/coresight/coresight-config.rst @@ -155,14 +155,14 @@ follows:: autofdo $ cd autofdo/ $ ls

• description preset1 preset3 preset5 preset7 preset9
• feature_refs preset2 preset4 preset6 preset8

• description feature_refs preset1 preset3 preset5 preset7 preset9
• enable preset preset2 preset4 preset6 preset8 $ cat description Setup ETMs with strobing for autofdo $ cat feature_refs strobing

-Each preset declared has a preset<n> subdirectory declared. The values for +Each preset declared has a 'preset<n>' subdirectory declared. The values for the preset can be examined::

 $ cat preset1/values

@@ -170,6 +170,9 @@ the preset can be examined:: $ cat preset2/values strobing.window = 0x1388 strobing.period = 0x4

+The 'enable' and 'preset' files allow the control of a configuration when +using CoreSight with sysfs.

The features referenced by the configuration can be examined in the features directory::

@@ -236,3 +239,56 @@ 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.

+Using Configurations in sysfs +=============================

+Coresight can be controlled using sysfs. When this is in use then a configuration +can be made active for the devices that are used in the sysfs session.

+In a configuration there are 'enable' and 'preset' files.

+To enable a configuration for use with sysfs::

• $ cd configurations/autofdo
• $ echo 1 > enable

+This will then use any default parameter values in the features - which can be +adjusted as described above.

+To use a preset<n> set of parameter values::

• $ echo 3 > preset

+This will select preset3 for the configuration. +The valid values for preset are 0 - to deselect presets, and any value of +<n> where a preset<n> sub-directory is present.

+Note that the active sysfs configuration is a global parameter, therefore +only a single configuration can be active for sysfs at any one time. +Attempting to enable a second configuration will result in an error. +Additionally, attempting to disable the configuration while in use will +also result in an error.

+The use of the active configuration by sysfs is independent of the configuration +used in perf.

Shouldn't all instances in the above section be configfs rather than sysfs? If so should I make the changes?

What I am trying to explain there is that when using sysfs to control CoreSight, it is possible to set a configuration using configfs, which is then used when a tracer is enabled under sysfs.

Mike

I have your patchset on stanby in my local coresight-next tree - just let me know.

Thanks, Mathieu

...

+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

On Mon, 29 Nov 2021 at 05:24, Mike Leach mike.leach@linaro.org wrote:

Hi Mathieu,

On Fri, 26 Nov 2021 at 18:23, Mathieu Poirier mathieu.poirier@linaro.org wrote:

...

On Wed, Nov 24, 2021 at 08:00:36PM +0000, Mike Leach wrote:

...

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 7a2345ce8521..85242fdd3b8c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1890,6 +1890,7 @@ 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 bec3528aa2de..fe8b56d576ce 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -232,6 +232,15 @@ 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

config HAVE_SAMPLE_FTRACE_DIRECT diff --git a/samples/Makefile b/samples/Makefile index b7b98307c2b4..c148ada64beb 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -32,3 +32,4 @@ 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",
  

Checkpatch is complaining the above should be "static const char * const ..." I can't remember if we talked about this before - did we?

The first Complex config set had the same warning for the built in autofdo config - which went upstream without issue. The code is safe - the strings are only ever read, the array is not altered - so perhaps that is why it was permitted - or maybe it was missed.

...

Do you want me to make the modification?

When I first so the issue in the original patch series - I made the suggested change and this had ripple effects of compile time warnings

• throwing away const.

If this is then corrected - the dynamic creation of configuration descriptors from configfs input files (in the follow up patch set) throws up errors The only way round this I could see would be to have two versions of the configuration descriptor - one that could be statically const assigned in the code, and one that could be dynamically build from file information.

Overall I am not convinced that there is a good fix for this checkpatch warning - and am not convinced that it is valid for this usecase.

... and I am definitely not convinced it is worth spending the time to fix this.

I have applied this patchset.

Thanks, Mathieu

Regards

Mike

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