diff options
Diffstat (limited to 'drivers/hwtracing/coresight/coresight-syscfg.c')
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-syscfg.c | 374 |
1 files changed, 293 insertions, 81 deletions
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 098fc34c4829..6836b05986e8 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -89,9 +89,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev, } /* if matched features, add config to device.*/ if (config_csdev) { - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_add(&config_csdev->node, &csdev->config_csdev_list); - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } return 0; @@ -194,9 +194,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev, /* add to internal csdev feature list & initialise using reset call */ cscfg_reset_feat(feat_csdev); - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_add(&feat_csdev->node, &csdev->feature_csdev_list); - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); return 0; } @@ -395,6 +395,8 @@ static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, voi if (list_empty(&csdev->config_csdev_list)) return; + guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock); + 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); @@ -415,6 +417,27 @@ static void cscfg_remove_owned_csdev_features(struct coresight_device *csdev, vo } /* + * Unregister all configuration and features from configfs owned by load_owner. + * Although this is called without the list mutex being held, it is in the + * context of an unload operation which are strictly serialised, + * so the lists cannot change during this call. + */ +static void cscfg_fs_unregister_cfgs_feats(void *load_owner) +{ + struct cscfg_config_desc *config_desc; + struct cscfg_feature_desc *feat_desc; + + list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) { + if (config_desc->load_owner == load_owner) + cscfg_configfs_del_config(config_desc); + } + list_for_each_entry(feat_desc, &cscfg_mgr->feat_desc_list, item) { + if (feat_desc->load_owner == load_owner) + cscfg_configfs_del_feature(feat_desc); + } +} + +/* * 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 @@ -426,6 +449,8 @@ static void cscfg_unload_owned_cfgs_feats(void *load_owner) struct cscfg_feature_desc *feat_desc, *feat_tmp; struct cscfg_registered_csdev *csdev_item; + lockdep_assert_held(&cscfg_mutex); + /* remove from each csdev instance feature and config lists */ list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) { /* @@ -439,7 +464,6 @@ static void cscfg_unload_owned_cfgs_feats(void *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); } @@ -448,12 +472,90 @@ static void cscfg_unload_owned_cfgs_feats(void *load_owner) /* 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); } } } +/* + * load the features and configs to the lists - called with list mutex held + */ +static int cscfg_load_owned_cfgs_feats(struct cscfg_config_desc **config_descs, + struct cscfg_feature_desc **feat_descs, + struct cscfg_load_owner_info *owner_info) +{ + int i, err; + + lockdep_assert_held(&cscfg_mutex); + + /* load features first */ + if (feat_descs) { + for (i = 0; feat_descs[i]; i++) { + err = cscfg_load_feat(feat_descs[i]); + if (err) { + pr_err("coresight-syscfg: Failed to load feature %s\n", + feat_descs[i]->name); + return err; + } + feat_descs[i]->load_owner = owner_info; + } + } + + /* next any configurations to check feature dependencies */ + if (config_descs) { + for (i = 0; config_descs[i]; i++) { + err = cscfg_load_config(config_descs[i]); + if (err) { + pr_err("coresight-syscfg: Failed to load configuration %s\n", + config_descs[i]->name); + return err; + } + config_descs[i]->load_owner = owner_info; + config_descs[i]->available = false; + } + } + return 0; +} + +/* set configurations as available to activate at the end of the load process */ +static void cscfg_set_configs_available(struct cscfg_config_desc **config_descs) +{ + int i; + + lockdep_assert_held(&cscfg_mutex); + + if (config_descs) { + for (i = 0; config_descs[i]; i++) + config_descs[i]->available = true; + } +} + +/* + * Create and register each of the configurations and features with configfs. + * Called without mutex being held. + */ +static int cscfg_fs_register_cfgs_feats(struct cscfg_config_desc **config_descs, + struct cscfg_feature_desc **feat_descs) +{ + int i, err; + + if (feat_descs) { + for (i = 0; feat_descs[i]; i++) { + err = cscfg_configfs_add_feature(feat_descs[i]); + if (err) + return err; + } + } + if (config_descs) { + for (i = 0; config_descs[i]; i++) { + err = cscfg_configfs_add_config(config_descs[i]); + if (err) + return err; + } + } + return 0; +} + /** * cscfg_load_config_sets - API function to load feature and config sets. * @@ -476,57 +578,63 @@ int cscfg_load_config_sets(struct cscfg_config_desc **config_descs, struct cscfg_feature_desc **feat_descs, struct cscfg_load_owner_info *owner_info) { - int err = 0, i = 0; + int err = 0; mutex_lock(&cscfg_mutex); - - /* load features first */ - if (feat_descs) { - while (feat_descs[i]) { - err = cscfg_load_feat(feat_descs[i]); - if (!err) - err = cscfg_configfs_add_feature(feat_descs[i]); - 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++; - } + if (cscfg_mgr->load_state != CSCFG_NONE) { + mutex_unlock(&cscfg_mutex); + return -EBUSY; } + cscfg_mgr->load_state = CSCFG_LOAD; - /* next any configurations to check feature dependencies */ - i = 0; - if (config_descs) { - while (config_descs[i]) { - err = cscfg_load_config(config_descs[i]); - if (!err) - err = cscfg_configfs_add_config(config_descs[i]); - 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++; - } - } + /* first load and add to the lists */ + err = cscfg_load_owned_cfgs_feats(config_descs, feat_descs, owner_info); + if (err) + goto err_clean_load; /* 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); - } + if (err) + goto err_clean_owner_list; } + /* + * make visible to configfs - configfs manipulation must occur outside + * the list mutex lock to avoid circular lockdep issues with configfs + * built in mutexes and semaphores. This is safe as it is not possible + * to start a new load/unload operation till the current one is done. + */ + mutex_unlock(&cscfg_mutex); + + /* create the configfs elements */ + err = cscfg_fs_register_cfgs_feats(config_descs, feat_descs); + mutex_lock(&cscfg_mutex); + + if (err) + goto err_clean_cfs; + + /* mark any new configs as available for activation */ + cscfg_set_configs_available(config_descs); + goto exit_unlock; + +err_clean_cfs: + /* cleanup after error registering with configfs */ + cscfg_fs_unregister_cfgs_feats(owner_info); + + if (!list_is_singular(&cscfg_mgr->load_order_list)) + cscfg_owner_put(list_prev_entry(owner_info, item)); + +err_clean_owner_list: + list_del(&owner_info->item); + +err_clean_load: + cscfg_unload_owned_cfgs_feats(owner_info); + exit_unlock: + cscfg_mgr->load_state = CSCFG_NONE; mutex_unlock(&cscfg_mutex); return err; } @@ -543,6 +651,9 @@ EXPORT_SYMBOL_GPL(cscfg_load_config_sets); * 1) no configurations are active. * 2) the set being unloaded was the last to be loaded to maintain dependencies. * + * Once the unload operation commences, we disallow any configuration being + * made active until it is complete. + * * @owner_info: Information on owner for set being unloaded. */ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info) @@ -551,6 +662,13 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info) struct cscfg_load_owner_info *load_list_item = NULL; mutex_lock(&cscfg_mutex); + if (cscfg_mgr->load_state != CSCFG_NONE) { + mutex_unlock(&cscfg_mutex); + return -EBUSY; + } + + /* unload op in progress also prevents activation of any config */ + cscfg_mgr->load_state = CSCFG_UNLOAD; /* cannot unload if anything is active */ if (atomic_read(&cscfg_mgr->sys_active_cnt)) { @@ -571,7 +689,12 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info) goto exit_unlock; } - /* unload all belonging to load_owner */ + /* remove from configfs - again outside the scope of the list mutex */ + mutex_unlock(&cscfg_mutex); + cscfg_fs_unregister_cfgs_feats(owner_info); + mutex_lock(&cscfg_mutex); + + /* unload everything from lists belonging to load_owner */ cscfg_unload_owned_cfgs_feats(owner_info); /* remove from load order list */ @@ -582,6 +705,7 @@ int cscfg_unload_config_sets(struct cscfg_load_owner_info *owner_info) list_del(&owner_info->item); exit_unlock: + cscfg_mgr->load_state = CSCFG_NONE; mutex_unlock(&cscfg_mutex); return err; } @@ -643,7 +767,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev, INIT_LIST_HEAD(&csdev->feature_csdev_list); INIT_LIST_HEAD(&csdev->config_csdev_list); - spin_lock_init(&csdev->cscfg_csdev_lock); + raw_spin_lock_init(&csdev->cscfg_csdev_lock); return 0; } @@ -733,7 +857,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev) struct cscfg_feature_csdev *feat_csdev; unsigned long flags; - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); if (list_empty(&csdev->feature_csdev_list)) goto unlock_exit; @@ -741,10 +865,29 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev) cscfg_reset_feat(feat_csdev); unlock_exit: - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats); +static bool cscfg_config_desc_get(struct cscfg_config_desc *config_desc) +{ + if (!atomic_fetch_inc(&config_desc->active_cnt)) { + /* must ensure that config cannot be unloaded in use */ + if (unlikely(cscfg_owner_get(config_desc->load_owner))) { + atomic_dec(&config_desc->active_cnt); + return false; + } + } + + return true; +} + +static void cscfg_config_desc_put(struct cscfg_config_desc *config_desc) +{ + if (!atomic_dec_return(&config_desc->active_cnt)) + cscfg_owner_put(config_desc->load_owner); +} + /* * This activate configuration for either perf or sysfs. Perf can have multiple * active configs, selected per event, sysfs is limited to one. @@ -759,24 +902,26 @@ static int _cscfg_activate_config(unsigned long cfg_hash) struct cscfg_config_desc *config_desc; int err = -EINVAL; + if (cscfg_mgr->load_state == CSCFG_UNLOAD) + return -EBUSY; + 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) + /* if we happen upon a partly loaded config, can't use it */ + if (config_desc->available == false) + return -EBUSY; + + if (!cscfg_config_desc_get(config_desc)) { + err = -EINVAL; break; + } + /* * increment the global active count - control changes to * active configurations */ atomic_inc(&cscfg_mgr->sys_active_cnt); - /* - * mark the descriptor as active so enable config on a - * device instance will use it - */ - atomic_inc(&config_desc->active_cnt); - err = 0; dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name); break; @@ -791,9 +936,8 @@ static void _cscfg_deactivate_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) { - atomic_dec(&config_desc->active_cnt); atomic_dec(&cscfg_mgr->sys_active_cnt); - cscfg_owner_put(config_desc->load_owner); + cscfg_config_desc_put(config_desc); dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name); break; } @@ -918,7 +1062,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, unsigned long cfg_hash, int preset) { struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item; - const struct cscfg_config_desc *config_desc; + struct cscfg_config_desc *config_desc; unsigned long flags; int err = 0; @@ -930,17 +1074,17 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * Look for matching configuration - set the active configuration * context if found. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) { config_desc = config_csdev_item->config_desc; - if ((atomic_read(&config_desc->active_cnt)) && - ((unsigned long)config_desc->event_ea->var == cfg_hash)) { + if (((unsigned long)config_desc->event_ea->var == cfg_hash) && + cscfg_config_desc_get(config_desc)) { config_csdev_active = config_csdev_item; csdev->active_cscfg_ctxt = (void *)config_csdev_active; break; } } - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* * If found, attempt to enable @@ -961,14 +1105,18 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * * Set enabled if OK, err if not. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); if (csdev->active_cscfg_ctxt) config_csdev_active->enabled = true; else err = -EBUSY; - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } + + if (err) + cscfg_config_desc_put(config_desc); } + return err; } EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config); @@ -995,7 +1143,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev) * If it was not enabled, we have no work to do, otherwise mark as disabled. * Clear the active config pointer. */ - spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); + raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; if (config_csdev) { if (!config_csdev->enabled) @@ -1004,11 +1152,13 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev) config_csdev->enabled = false; } csdev->active_cscfg_ctxt = NULL; - spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); + raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* true if there was an enabled active config */ - if (config_csdev) + if (config_csdev) { cscfg_csdev_disable_config(config_csdev); + cscfg_config_desc_put(config_csdev->config_desc); + } } EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config); @@ -1022,8 +1172,10 @@ struct device *cscfg_device(void) /* Must have a release function or the kernel will complain on module unload */ static void cscfg_dev_release(struct device *dev) { + mutex_lock(&cscfg_mutex); kfree(cscfg_mgr); cscfg_mgr = NULL; + mutex_unlock(&cscfg_mutex); } /* a device is needed to "own" some kernel elements such as sysfs entries. */ @@ -1042,6 +1194,14 @@ static int cscfg_create_device(void) if (!cscfg_mgr) goto create_dev_exit_unlock; + /* initialise the cscfg_mgr structure */ + 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); + cscfg_mgr->load_state = CSCFG_NONE; + /* setup the device */ dev = cscfg_device(); dev->release = cscfg_dev_release; @@ -1049,24 +1209,80 @@ static int cscfg_create_device(void) err = device_register(dev); if (err) - cscfg_dev_release(dev); + put_device(dev); create_dev_exit_unlock: mutex_unlock(&cscfg_mutex); return err; } -static void cscfg_clear_device(void) +/* + * Loading and unloading is generally on user discretion. + * If exiting due to coresight module unload, we need to unload any configurations that remain, + * before we unregister the configfs intrastructure. + * + * Do this by walking the load_owner list and taking appropriate action, depending on the load + * owner type. + */ +static void cscfg_unload_cfgs_on_exit(void) { - struct cscfg_config_desc *cfg_desc; + struct cscfg_load_owner_info *owner_info = NULL; + /* + * grab the mutex - even though we are exiting, some configfs files + * may still be live till we dump them, so ensure list data is + * protected from a race condition. + */ mutex_lock(&cscfg_mutex); - list_for_each_entry(cfg_desc, &cscfg_mgr->config_desc_list, item) { - etm_perf_del_symlink_cscfg(cfg_desc); + while (!list_empty(&cscfg_mgr->load_order_list)) { + + /* remove in reverse order of loading */ + owner_info = list_last_entry(&cscfg_mgr->load_order_list, + struct cscfg_load_owner_info, item); + + /* action according to type */ + switch (owner_info->type) { + case CSCFG_OWNER_PRELOAD: + /* + * preloaded descriptors are statically allocated in + * this module - just need to unload dynamic items from + * csdev lists, and remove from configfs directories. + */ + pr_info("cscfg: unloading preloaded configurations\n"); + break; + + case CSCFG_OWNER_MODULE: + /* + * this is an error - the loadable module must have been unloaded prior + * to the coresight module unload. Therefore that module has not + * correctly unloaded configs in its own exit code. + * Nothing to do other than emit an error string as the static descriptor + * references we need to unload will have disappeared with the module. + */ + pr_err("cscfg: ERROR: prior module failed to unload configuration\n"); + goto list_remove; + } + + /* remove from configfs - outside the scope of the list mutex */ + mutex_unlock(&cscfg_mutex); + cscfg_fs_unregister_cfgs_feats(owner_info); + mutex_lock(&cscfg_mutex); + + /* Next unload from csdev lists. */ + cscfg_unload_owned_cfgs_feats(owner_info); + +list_remove: + /* remove from load order list */ + list_del(&owner_info->item); } + mutex_unlock(&cscfg_mutex); +} + +static void cscfg_clear_device(void) +{ + cscfg_unload_cfgs_on_exit(); cscfg_configfs_release(cscfg_mgr); device_unregister(cscfg_device()); - mutex_unlock(&cscfg_mutex); } /* Initialise system config management API device */ @@ -1074,20 +1290,16 @@ int __init cscfg_init(void) { int err = 0; + /* create the device and init cscfg_mgr */ err = cscfg_create_device(); if (err) return err; + /* initialise configfs subsystem */ err = cscfg_configfs_init(cscfg_mgr); if (err) goto exit_err; - 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(THIS_MODULE); if (err) |
