On Wed, May 12, 2021 at 10:17:46PM +0100, Mike Leach wrote:
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:-
Please remove the '-'. It is not a big issue but you can be sure the various patch robots will complain. With that:
Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org
- if the config it supplies is in use
- if the module is not the last in the load order list.
Signed-off-by: Mike Leach mike.leach@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 ab5ec43a9dad..26c1a244c2b1 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); @@ -737,6 +769,10 @@ 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@@ -777,6 +813,7 @@ 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