#include "error.h"
/* Test compiler support for weak symbols with hidden visibility. */
-char __tracepoint_test_symbol[9] __attribute__((weak, visibility("hidden")));
+int __tracepoint_test_symbol1 __attribute__((weak, visibility("hidden")));
+void *__tracepoint_test_symbol2 __attribute__((weak, visibility("hidden")));
+struct {
+ char a[24];
+} __tracepoint_test_symbol3 __attribute__((weak, visibility("hidden")));
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
static CDS_LIST_HEAD(old_probes);
static int need_update;
+static CDS_LIST_HEAD(release_queue);
+static int release_queue_need_update;
+
/*
* Note about RCU :
* It is used to to delay the free of multiple probes array until a quiescent
return old;
}
+static void tracepoint_release_queue_add_old_probes(void *old)
+{
+ release_queue_need_update = 1;
+ if (old) {
+ struct tp_probes *tp_probes = caa_container_of(old,
+ struct tp_probes, probes[0]);
+ cds_list_add(&tp_probes->u.list, &release_queue);
+ }
+}
+
/**
* __tracepoint_probe_register - Connect a probe to a tracepoint
* @name: tracepoint name
return ret;
}
+/*
+ * Caller needs to invoke __tracepoint_probe_release_queue() after
+ * calling __tracepoint_probe_register_queue_release() one or multiple
+ * times to ensure it does not leak memory.
+ */
+int __tracepoint_probe_register_queue_release(const char *name,
+ void (*probe)(void), void *data, const char *signature)
+{
+ void *old;
+ int ret = 0;
+
+ DBG("Registering probe to tracepoint %s. Queuing release.", name);
+
+ pthread_mutex_lock(&tracepoint_mutex);
+ old = tracepoint_add_probe(name, probe, data, signature);
+ if (IS_ERR(old)) {
+ ret = PTR_ERR(old);
+ goto end;
+ }
+
+ tracepoint_sync_callsites(name);
+ tracepoint_release_queue_add_old_probes(old);
+end:
+ pthread_mutex_unlock(&tracepoint_mutex);
+ return ret;
+}
+
static void *tracepoint_remove_probe(const char *name, void (*probe)(void),
void *data)
{
return ret;
}
+/*
+ * Caller needs to invoke __tracepoint_probe_release_queue() after
+ * calling __tracepoint_probe_unregister_queue_release() one or multiple
+ * times to ensure it does not leak memory.
+ */
+int __tracepoint_probe_unregister_queue_release(const char *name,
+ void (*probe)(void), void *data)
+{
+ void *old;
+ int ret = 0;
+
+ DBG("Un-registering probe from tracepoint %s. Queuing release.", name);
+
+ pthread_mutex_lock(&tracepoint_mutex);
+ old = tracepoint_remove_probe(name, probe, data);
+ if (IS_ERR(old)) {
+ ret = PTR_ERR(old);
+ goto end;
+ }
+ tracepoint_sync_callsites(name);
+ tracepoint_release_queue_add_old_probes(old);
+end:
+ pthread_mutex_unlock(&tracepoint_mutex);
+ return ret;
+}
+
+void __tracepoint_probe_prune_release_queue(void)
+{
+ CDS_LIST_HEAD(release_probes);
+ struct tp_probes *pos, *next;
+
+ DBG("Release queue of unregistered tracepoint probes.");
+
+ pthread_mutex_lock(&tracepoint_mutex);
+ if (!release_queue_need_update)
+ goto end;
+ if (!cds_list_empty(&release_queue))
+ cds_list_replace_init(&release_queue, &release_probes);
+ release_queue_need_update = 0;
+
+ /* Wait for grace period between all sync_callsites and free. */
+ synchronize_rcu();
+
+ cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
+ cds_list_del(&pos->u.list);
+ free(pos);
+ }
+end:
+ pthread_mutex_unlock(&tracepoint_mutex);
+}
+
static void tracepoint_add_old_probes(void *old)
{
need_update = 1;
need_update = 0;
tracepoint_update_probes();
+ /* Wait for grace period between update_probes and free. */
+ synchronize_rcu();
cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
cds_list_del(&pos->u.list);
- synchronize_rcu();
free(pos);
}
end:
*/
static void check_weak_hidden(void)
{
- DBG("Your compiler support for weak symbols with hidden visibility is %s",
- __tracepoint_test_symbol == lttng_ust_tp_check_weak_hidden() ?
- "OK" :
- "BROKEN. Please upgrade or fix your compiler to use LTTng-UST tracepoints.");
+ DBG("Your compiler treats weak symbols with hidden visibility for integer objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol1 == lttng_ust_tp_check_weak_hidden1() ?
+ "SAME address" :
+ "DIFFERENT addresses");
+ DBG("Your compiler treats weak symbols with hidden visibility for pointer objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol2 == lttng_ust_tp_check_weak_hidden2() ?
+ "SAME address" :
+ "DIFFERENT addresses");
+ DBG("Your compiler treats weak symbols with hidden visibility for 24-byte structure objects as %s between compile units part of the same module.",
+ &__tracepoint_test_symbol3 == lttng_ust_tp_check_weak_hidden3() ?
+ "SAME address" :
+ "DIFFERENT addresses");
}
void init_tracepoint(void)