#include "tracer.h"
#include "rcu.h"
+#include "list.h"
/* Top 8 bits reserved for kernel tracer use. */
-#define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000
-#define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000
+#if SIDE_BITS_PER_LONG == 64
+# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF00000000000000ULL
+# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x8000000000000000ULL
-/* Allow 2^24 tracer callbacks to be registered on an event. */
-#define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFF
+/* Allow 2^56 tracer references on an event. */
+# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFFFFFFFFFULL
+#else
+# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000UL
+# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000UL
+
+/* Allow 2^24 tracer references on an event. */
+# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFUL
+#endif
+
+struct side_events_register_handle {
+ struct side_list_node node;
+ struct side_event_description **events;
+ uint32_t nr_events;
+};
+
+struct side_tracer_handle {
+ struct side_list_node node;
+ void (*cb)(enum side_tracer_notification notif,
+ struct side_event_description **events, uint32_t nr_events, void *priv);
+ void *priv;
+};
static struct side_rcu_gp_state rcu_gp;
* Lazy initialization for early use within library constructors.
*/
static bool initialized;
+/*
+ * Do not register/unregister any more events after destructor.
+ */
+static bool finalized;
static pthread_mutex_t side_lock = PTHREAD_MUTEX_INITIALIZER;
-static
-void side_init(void)
- __attribute__((constructor));
+static DEFINE_SIDE_LIST_HEAD(side_events_list);
+static DEFINE_SIDE_LIST_HEAD(side_tracer_list);
/*
* The empty callback has a NULL function callback pointer, which stops
*/
const struct side_callback side_empty_callback;
+void side_init(void) __attribute__((constructor));
+void side_exit(void) __attribute__((destructor));
+
void side_call(const struct side_event_description *desc, const struct side_arg_vec_description *sav_desc)
{
const struct side_callback *side_cb;
unsigned int rcu_period;
- uint32_t enabled;
+ uintptr_t enabled;
+ if (side_unlikely(finalized))
+ return;
if (side_unlikely(!initialized))
side_init();
if (side_unlikely(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) {
if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK)))
return;
- //TODO: replace tracer_call by rcu iteration on list of registered callbacks
- tracer_call(desc, sav_desc, NULL);
-
rcu_period = side_rcu_read_begin(&rcu_gp);
for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call != NULL; side_cb++)
side_cb->u.call(desc, sav_desc, side_cb->priv);
{
const struct side_callback *side_cb;
unsigned int rcu_period;
- uint32_t enabled;
+ uintptr_t enabled;
+ if (side_unlikely(finalized))
+ return;
if (side_unlikely(!initialized))
side_init();
if (side_unlikely(!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))) {
if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK)))
return;
- //TODO: replace tracer_call by rcu iteration on list of registered callbacks
- tracer_call_variadic(desc, sav_desc, var_struct, NULL);
-
rcu_period = side_rcu_read_begin(&rcu_gp);
for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call_variadic != NULL; side_cb++)
side_cb->u.call_variadic(desc, sav_desc, var_struct, side_cb->priv);
if (!call)
return SIDE_ERROR_INVAL;
+ if (finalized)
+ return SIDE_ERROR_EXITING;
+ if (!initialized)
+ side_init();
pthread_mutex_lock(&side_lock);
- old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK;
- if (old_nr_cb == SIDE_EVENT_ENABLED_USER_MASK) {
+ old_nr_cb = desc->nr_callbacks;
+ if (old_nr_cb == UINT32_MAX) {
ret = SIDE_ERROR_INVAL;
goto unlock;
}
side_rcu_wait_grace_period(&rcu_gp);
if (old_nr_cb)
free(old_cb);
+ desc->nr_callbacks++;
/* Increment concurrently with kernel setting the top bits. */
- (void) __atomic_add_fetch(desc->enabled, 1, __ATOMIC_RELAXED);
+ if (!old_nr_cb)
+ (void) __atomic_add_fetch(desc->enabled, 1, __ATOMIC_RELAXED);
unlock:
pthread_mutex_unlock(&side_lock);
return ret;
if (!call)
return SIDE_ERROR_INVAL;
+ if (finalized)
+ return SIDE_ERROR_EXITING;
+ if (!initialized)
+ side_init();
pthread_mutex_lock(&side_lock);
cb_pos = side_tracer_callback_lookup(desc, call, priv);
if (!cb_pos) {
ret = SIDE_ERROR_NOENT;
goto unlock;
}
- old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK;
+ old_nr_cb = desc->nr_callbacks;
old_cb = (struct side_callback *) desc->callbacks;
if (old_nr_cb == 1) {
new_cb = (struct side_callback *) &side_empty_callback;
side_rcu_assign_pointer(desc->callbacks, new_cb);
side_rcu_wait_grace_period(&rcu_gp);
free(old_cb);
+ desc->nr_callbacks--;
/* Decrement concurrently with kernel setting the top bits. */
- (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
+ if (old_nr_cb == 1)
+ (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
unlock:
pthread_mutex_unlock(&side_lock);
return ret;
return _side_tracer_callback_unregister(desc, call_variadic, priv);
}
+struct side_events_register_handle *side_events_register(struct side_event_description **events, uint32_t nr_events)
+{
+ struct side_events_register_handle *events_handle = NULL;
+ struct side_tracer_handle *tracer_handle;
+
+ if (finalized)
+ return NULL;
+ if (!initialized)
+ side_init();
+ events_handle = calloc(1, sizeof(struct side_events_register_handle));
+ if (!events_handle)
+ return NULL;
+ events_handle->events = events;
+ events_handle->nr_events = nr_events;
+
+ pthread_mutex_lock(&side_lock);
+ side_list_insert_node_tail(&side_events_list, &events_handle->node);
+ side_list_for_each_entry(tracer_handle, &side_tracer_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS,
+ events, nr_events, tracer_handle->priv);
+ }
+ pthread_mutex_unlock(&side_lock);
+ //TODO: call event batch register ioctl
+ return events_handle;
+}
+
static
+void side_event_remove_callbacks(struct side_event_description *desc)
+{
+ uint32_t nr_cb = desc->nr_callbacks;
+ struct side_callback *old_cb;
+
+ if (!nr_cb)
+ return;
+ old_cb = (struct side_callback *) desc->callbacks;
+ (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
+ /*
+ * Setting the state back to 0 cb and empty callbacks out of
+ * caution. This should not matter because instrumentation is
+ * unreachable.
+ */
+ desc->nr_callbacks = 0;
+ side_rcu_assign_pointer(desc->callbacks, &side_empty_callback);
+ /*
+ * No need to wait for grace period because instrumentation is
+ * unreachable.
+ */
+ free(old_cb);
+}
+
+/*
+ * Unregister event handle. At this point, all side events in that
+ * handle should be unreachable.
+ */
+void side_events_unregister(struct side_events_register_handle *events_handle)
+{
+ struct side_tracer_handle *tracer_handle;
+ uint32_t i;
+
+ if (!events_handle)
+ return;
+ if (finalized)
+ return;
+ if (!initialized)
+ side_init();
+ pthread_mutex_lock(&side_lock);
+ side_list_remove_node(&events_handle->node);
+ side_list_for_each_entry(tracer_handle, &side_tracer_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS,
+ events_handle->events, events_handle->nr_events,
+ tracer_handle->priv);
+ }
+ for (i = 0; i < events_handle->nr_events; i++) {
+ struct side_event_description *event = events_handle->events[i];
+
+ /* Skip NULL pointers */
+ if (!event)
+ continue;
+ side_event_remove_callbacks(event);
+ }
+ pthread_mutex_unlock(&side_lock);
+ //TODO: call event batch unregister ioctl
+ free(events_handle);
+}
+
+struct side_tracer_handle *side_tracer_event_notification_register(
+ void (*cb)(enum side_tracer_notification notif,
+ struct side_event_description **events, uint32_t nr_events, void *priv),
+ void *priv)
+{
+ struct side_tracer_handle *tracer_handle;
+ struct side_events_register_handle *events_handle;
+
+ if (finalized)
+ return NULL;
+ if (!initialized)
+ side_init();
+ tracer_handle = calloc(1, sizeof(struct side_tracer_handle));
+ if (!tracer_handle)
+ return NULL;
+ pthread_mutex_lock(&side_lock);
+ tracer_handle->cb = cb;
+ tracer_handle->priv = priv;
+ side_list_insert_node_tail(&side_tracer_list, &tracer_handle->node);
+ side_list_for_each_entry(events_handle, &side_events_list, node) {
+ cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS,
+ events_handle->events, events_handle->nr_events, priv);
+ }
+ pthread_mutex_unlock(&side_lock);
+ return tracer_handle;
+}
+
+void side_tracer_event_notification_unregister(struct side_tracer_handle *tracer_handle)
+{
+ struct side_events_register_handle *events_handle;
+
+ if (finalized)
+ return;
+ if (!initialized)
+ side_init();
+ pthread_mutex_lock(&side_lock);
+ side_list_for_each_entry(events_handle, &side_events_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS,
+ events_handle->events, events_handle->nr_events,
+ tracer_handle->priv);
+ }
+ side_list_remove_node(&tracer_handle->node);
+ pthread_mutex_unlock(&side_lock);
+}
+
void side_init(void)
{
if (initialized)
side_rcu_gp_init(&rcu_gp);
initialized = true;
}
+
+/*
+ * side_exit() is executed from a library destructor. It can be called
+ * explicitly at application exit as well. Concurrent side API use is
+ * not expected at that point.
+ */
+void side_exit(void)
+{
+ struct side_events_register_handle *handle, *tmp;
+
+ if (finalized)
+ return;
+ side_rcu_gp_exit(&rcu_gp);
+ side_list_for_each_entry_safe(handle, tmp, &side_events_list, node)
+ side_events_unregister(handle);
+ finalized = true;
+}
projects / libside.git / blobdiff