+static
+bool lttng_kernel_event_id_available(struct lttng_event_enabler_common *event_enabler)
+{
+ struct lttng_kernel_abi_event *event_param = &event_enabler->event_param;
+ enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+
+ switch (event_enabler->enabler_type) {
+ case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+ {
+ struct lttng_event_recorder_enabler *event_recorder_enabler =
+ container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+ struct lttng_kernel_channel_buffer *chan = event_recorder_enabler->chan;
+
+ switch (itype) {
+ case LTTNG_KERNEL_ABI_TRACEPOINT:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_KPROBE:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_SYSCALL:
+ lttng_fallthrough;
+ case LTTNG_KERNEL_ABI_UPROBE:
+ if (chan->priv->free_event_id == -1U)
+ return false;
+ return true;
+ case LTTNG_KERNEL_ABI_KRETPROBE:
+ /* kretprobes require 2 event IDs. */
+ if (chan->priv->free_event_id >= -2U)
+ return false;
+ return true;
+ default:
+ WARN_ON_ONCE(1);
+ return false;
+ }
+ }
+ case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+ return true;
+ default:
+ WARN_ON_ONCE(1);
+ return false;
+ }
+}
+
+static
+struct lttng_kernel_event_common *lttng_kernel_event_alloc(struct lttng_event_enabler_common *event_enabler)
+{
+ struct lttng_kernel_abi_event *event_param = &event_enabler->event_param;
+ enum lttng_kernel_abi_instrumentation itype = event_param->instrumentation;
+
+ switch (event_enabler->enabler_type) {
+ case LTTNG_EVENT_ENABLER_TYPE_RECORDER:
+ {
+ struct lttng_event_recorder_enabler *event_recorder_enabler =
+ container_of(event_enabler, struct lttng_event_recorder_enabler, parent);
+ struct lttng_kernel_event_recorder *event_recorder;
+ struct lttng_kernel_event_recorder_private *event_recorder_priv;
+ struct lttng_kernel_channel_buffer *chan = event_recorder_enabler->chan;
+
+ event_recorder = kmem_cache_zalloc(event_recorder_cache, GFP_KERNEL);
+ if (!event_recorder)
+ return NULL;
+ event_recorder_priv = kmem_cache_zalloc(event_recorder_private_cache, GFP_KERNEL);
+ if (!event_recorder_priv) {
+ kmem_cache_free(event_recorder_private_cache, event_recorder);
+ return NULL;
+ }
+ event_recorder_priv->pub = event_recorder;
+ event_recorder_priv->parent.pub = &event_recorder->parent;
+ event_recorder->priv = event_recorder_priv;
+ event_recorder->parent.priv = &event_recorder_priv->parent;
+
+ event_recorder->parent.type = LTTNG_KERNEL_EVENT_TYPE_RECORDER;
+ event_recorder->parent.run_filter = lttng_kernel_interpret_event_filter;
+ event_recorder->priv->parent.instrumentation = itype;
+ INIT_LIST_HEAD(&event_recorder->priv->parent.filter_bytecode_runtime_head);
+ INIT_LIST_HEAD(&event_recorder->priv->parent.enablers_ref_head);
+
+ event_recorder->chan = chan;
+ event_recorder->priv->id = chan->priv->free_event_id++;
+ return &event_recorder->parent;
+ }
+ case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
+ {
+ struct lttng_event_notifier_enabler *event_notifier_enabler =
+ container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
+ struct lttng_kernel_event_notifier *event_notifier;
+ struct lttng_kernel_event_notifier_private *event_notifier_priv;
+
+ event_notifier = kmem_cache_zalloc(event_notifier_cache, GFP_KERNEL);
+ if (!event_notifier)
+ return NULL;
+ event_notifier_priv = kmem_cache_zalloc(event_notifier_private_cache, GFP_KERNEL);
+ if (!event_notifier_priv) {
+ kmem_cache_free(event_notifier_private_cache, event_notifier);
+ return NULL;
+ }
+ event_notifier_priv->pub = event_notifier;
+ event_notifier_priv->parent.pub = &event_notifier->parent;
+ event_notifier->priv = event_notifier_priv;
+ event_notifier->parent.priv = &event_notifier_priv->parent;
+
+ event_notifier->parent.type = LTTNG_KERNEL_EVENT_TYPE_NOTIFIER;
+ event_notifier->parent.run_filter = lttng_kernel_interpret_event_filter;
+ event_notifier->priv->parent.instrumentation = itype;
+ event_notifier->priv->parent.user_token = event_enabler->user_token;
+ INIT_LIST_HEAD(&event_notifier->priv->parent.filter_bytecode_runtime_head);
+ INIT_LIST_HEAD(&event_notifier->priv->parent.enablers_ref_head);
+
+ event_notifier->priv->group = event_notifier_enabler->group;
+ event_notifier->priv->error_counter_index = event_notifier_enabler->error_counter_index;
+ event_notifier->priv->num_captures = 0;
+ event_notifier->notification_send = lttng_event_notifier_notification_send;
+ INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
+ return &event_notifier->parent;
+ }
+ default:
+ return NULL;
+ }
+}
+
+static
+void lttng_kernel_event_free(struct lttng_kernel_event_common *event)
+{
+ switch (event->type) {
+ case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+ {
+ struct lttng_kernel_event_recorder *event_recorder =
+ container_of(event, struct lttng_kernel_event_recorder, parent);
+
+ kmem_cache_free(event_recorder_private_cache, event_recorder->priv);
+ kmem_cache_free(event_recorder_cache, event_recorder);
+ break;
+ }
+ case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+ {
+ struct lttng_kernel_event_notifier *event_notifier =
+ container_of(event, struct lttng_kernel_event_notifier, parent);
+
+ kmem_cache_free(event_notifier_private_cache, event_notifier->priv);
+ kmem_cache_free(event_notifier_cache, event_notifier);
+ break;
+ }
+ default:
+ WARN_ON_ONCE(1);
+ }
+}
+
+static
+int lttng_kernel_event_notifier_clear_error_counter(struct lttng_kernel_event_common *event)
+{
+ switch (event->type) {
+ case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+ return 0;
+ case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
+ {
+ struct lttng_kernel_event_notifier *event_notifier =
+ container_of(event, struct lttng_kernel_event_notifier, parent);
+ struct lttng_counter *error_counter;
+ struct lttng_event_notifier_group *event_notifier_group = event_notifier->priv->group;
+ size_t dimension_index[1];
+ int ret;
+
+ /*
+ * Clear the error counter bucket. The sessiond keeps track of which
+ * bucket is currently in use. We trust it. The session lock
+ * synchronizes against concurrent creation of the error
+ * counter.
+ */
+ error_counter = event_notifier_group->error_counter;
+ if (!error_counter)
+ return 0;
+ /*
+ * Check that the index is within the boundary of the counter.
+ */
+ if (event_notifier->priv->error_counter_index >= event_notifier_group->error_counter_len) {
+ printk(KERN_INFO "LTTng: event_notifier: Error counter index out-of-bound: counter-len=%zu, index=%llu\n",
+ event_notifier_group->error_counter_len, event_notifier->priv->error_counter_index);
+ return -EINVAL;
+ }
+
+ dimension_index[0] = event_notifier->priv->error_counter_index;
+ ret = error_counter->ops->counter_clear(error_counter->counter, dimension_index);
+ if (ret) {
+ printk(KERN_INFO "LTTng: event_notifier: Unable to clear error counter bucket %llu\n",
+ event_notifier->priv->error_counter_index);
+ return -EINVAL;
+ }
+ return 0;
+ }
+ default:
+ return -EINVAL;
+ }
+}