diff options
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-syscfg.c | 39 | ||||
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-syscfg.h | 1 |
2 files changed, 39 insertions, 1 deletions
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 @@ unlock_exit: 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, }; /** |