@@ -1056,14 +1056,61 @@ static int cscfg_create_device(void)
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.
+ *
+ * called with the cscfg_mutex held
+ */
+
+#define LOADABLE_MOD_ERR "cscfg: ERROR - a loadable module failed to unload configs on exit\n"
+
+static void cscfg_unload_cfgs_on_exit(void)
{
- struct cscfg_config_desc *cfg_desc;
+ struct cscfg_load_owner_info *owner_info = NULL;
- 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");
+ cscfg_unload_owned_cfgs_feats(owner_info);
+ 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.
+ */
+ pr_err(LOADABLE_MOD_ERR);
+ break;
+ }
+
+ /* remove from load order list */
+ list_del(&owner_info->item);
}
+}
+
+static void cscfg_clear_device(void)
+{
+ mutex_lock(&cscfg_mutex);
+ cscfg_unload_cfgs_on_exit();
cscfg_configfs_release(cscfg_mgr);
device_unregister(cscfg_device());
mutex_unlock(&cscfg_mutex);
Any loaded configurations must be correctly unloaded on coresight module exit, or issues can arise with nested locking in the configfs directory code if built with CONFIG_LOCKDEP. Prior to this patch, the preloaded configuration configfs directory entries were being unloaded by the recursive code in configfs_unregister_subsystem(). However, when built with CONFIG_LOCKDEP, this caused a nested lock warning, which was not mitigated by the LOCKDEP dependent code in fs/configfs/dir.c designed to prevent this, due to the different directory levels for the root of the directory being removed. As the preloaded (and all other) configurations are registered after configfs_register_subsystem(), we now explicitly unload them before the call to configfs_unregister_subsystem(). The new routine cscfg_unload_cfgs_on_exit() iterates through the load owner list to unload any remaining configurations that were not unloaded by the user before the module exits. This covers both the CSCFG_OWNER_PRELOAD and CSCFG_OWNER_MODULE owner types, and will be extended to cover future load owner types for CoreSight configurations. Applies to coresight/next Fixes: eb2ec49606c2 ("coresight: syscfg: Update load API for config loadable modules") Reported-by: Suzuki Poulose <suzuki.poulose@arm.com> Signed-off-by: Mike Leach <mike.leach@linaro.org> --- .../hwtracing/coresight/coresight-syscfg.c | 57 +++++++++++++++++-- 1 file changed, 52 insertions(+), 5 deletions(-)