-static int tracepoint_v1_api_used;
-static void (*lttng_ust_liburcu_bp_synchronize_rcu)(void);
-static void (*lttng_ust_liburcu_bp_rcu_read_lock)(void);
-static void (*lttng_ust_liburcu_bp_rcu_read_unlock)(void);
-void (*lttng_ust_liburcu_bp_before_fork)(void);
-void (*lttng_ust_liburcu_bp_after_fork_parent)(void);
-void (*lttng_ust_liburcu_bp_after_fork_child)(void);
-
-static bool lttng_ust_tracepoint_v1_used(void)
-{
- return uatomic_read(&tracepoint_v1_api_used);
-}
-
-static void lttng_ust_tracepoint_set_v1_used(void)
-{
- if (!lttng_ust_tracepoint_v1_used()) {
- /*
- * Perform dlsym here rather than lazily on first use to
- * eliminate nesting of dynamic loader lock (used within
- * dlsym) inside the ust lock.
- */
- if (!lttng_ust_liburcu_bp_synchronize_rcu) {
- lttng_ust_liburcu_bp_synchronize_rcu = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "synchronize_rcu_bp"));
- /*
- * Allow legacy applications compiled without
- * _LGPL_SOURCE to use v1 API. Those are not
- * required to be linked against liburcu-bp,
- * so in those situations the liburcu-bp symbols
- * are not present in the global symbol table,
- * and we do not need to call urcu-bp
- * synchronize.
- *
- * However, nothing prevents a _LGPL_SOURCE
- * instrumented library loaded afterwards to
- * require liburcu-bp, so we need to check again
- * in that situation.
- */
- if (!lttng_ust_liburcu_bp_synchronize_rcu)
- return;
- }
- if (!lttng_ust_liburcu_bp_before_fork) {
- lttng_ust_liburcu_bp_before_fork = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "rcu_bp_before_fork"));
- if (!lttng_ust_liburcu_bp_before_fork)
- abort();
- }
- if (!lttng_ust_liburcu_bp_after_fork_parent) {
- lttng_ust_liburcu_bp_after_fork_parent = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "rcu_bp_after_fork_parent"));
- if (!lttng_ust_liburcu_bp_after_fork_parent)
- abort();
- }
- if (!lttng_ust_liburcu_bp_after_fork_child) {
- lttng_ust_liburcu_bp_after_fork_child = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "rcu_bp_after_fork_child"));
- if (!lttng_ust_liburcu_bp_after_fork_child)
- abort();
- }
- if (!lttng_ust_liburcu_bp_rcu_read_lock) {
- lttng_ust_liburcu_bp_rcu_read_lock = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "rcu_read_lock_bp"));
- if (!lttng_ust_liburcu_bp_rcu_read_lock)
- abort();
- }
- if (!lttng_ust_liburcu_bp_rcu_read_unlock) {
- lttng_ust_liburcu_bp_rcu_read_unlock = URCU_FORCE_CAST(void (*)(void),
- dlsym(RTLD_DEFAULT, "rcu_read_unlock_bp"));
- if (!lttng_ust_liburcu_bp_rcu_read_unlock)
- abort();
- }
-
- /* Fixup URCU bp TLS. */
- lttng_ust_liburcu_bp_rcu_read_lock();
- lttng_ust_liburcu_bp_rcu_read_unlock();
-
- uatomic_set(&tracepoint_v1_api_used, 1);
- }
-}
-