struct hlist_node hlist;
struct tracepoint_func *funcs;
int refcount; /* Number of times armed. 0 if disarmed. */
+ int enabled; /* Tracepoint enabled */
char name[0];
};
struct tp_probes {
- union {
- struct rcu_head rcu;
- struct list_head list;
- } u;
+ struct rcu_head rcu;
struct tracepoint_func probes[0];
};
static void rcu_free_old_probes(struct rcu_head *head)
{
- kfree(container_of(head, struct tp_probes, u.rcu));
+ kfree(container_of(head, struct tp_probes, rcu));
}
static inline void release_probes(struct tracepoint_func *old)
if (old) {
struct tp_probes *tp_probes = container_of(old,
struct tp_probes, probes[0]);
- call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
+ call_rcu_sched(&tp_probes->rcu, rcu_free_old_probes);
}
}
memcpy(&e->name[0], name, name_len);
e->funcs = NULL;
e->refcount = 0;
+ e->enabled = 0;
hlist_add_head(&e->hlist, head);
return e;
}
if (mark_entry) {
set_tracepoint(&mark_entry, *iter,
!!mark_entry->refcount);
+ mark_entry->enabled = !!mark_entry->refcount;
} else {
disable_tracepoint(*iter);
}
* tracepoint_probe_register - Connect a probe to a tracepoint
* @name: tracepoint name
* @probe: probe handler
+ * @data: probe private data
+ *
+ * Returns:
+ * - 0 if the probe was successfully registered, and tracepoint
+ * callsites are currently loaded for that probe,
+ * - -ENODEV if the probe was successfully registered, but no tracepoint
+ * callsite is currently loaded for that probe,
+ * - other negative error value on error.
+ *
+ * When tracepoint_probe_register() returns either 0 or -ENODEV,
+ * parameters @name, @probe, and @data may be used by the tracepoint
+ * infrastructure until the probe is unregistered.
*
- * Returns 0 if ok, error value on error.
* The probe address must at least be aligned on the architecture pointer size.
*/
int tracepoint_probe_register(const char *name, void *probe, void *data)
{
struct tracepoint_func *old;
+ struct tracepoint_entry *entry;
+ int ret = 0;
mutex_lock(&tracepoints_mutex);
old = tracepoint_add_probe(name, probe, data);
return PTR_ERR(old);
}
tracepoint_update_probes(); /* may update entry */
+ entry = get_tracepoint(name);
+ /* Make sure the entry was enabled */
+ if (!entry || !entry->enabled)
+ ret = -ENODEV;
mutex_unlock(&tracepoints_mutex);
release_probes(old);
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
* @name: tracepoint name
* @probe: probe function pointer
+ * @data: probe private data
*
* We do not need to call a synchronize_sched to make sure the probes have
* finished running before doing a module unload, because the module unload
}
EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
-static LIST_HEAD(old_probes);
-static int need_update;
-
-static void tracepoint_add_old_probes(void *old)
-{
- need_update = 1;
- if (old) {
- struct tp_probes *tp_probes = container_of(old,
- struct tp_probes, probes[0]);
- list_add(&tp_probes->u.list, &old_probes);
- }
-}
-
-/**
- * tracepoint_probe_register_noupdate - register a probe but not connect
- * @name: tracepoint name
- * @probe: probe handler
- *
- * caller must call tracepoint_probe_update_all()
- */
-int tracepoint_probe_register_noupdate(const char *name, void *probe,
- void *data)
-{
- struct tracepoint_func *old;
-
- mutex_lock(&tracepoints_mutex);
- old = tracepoint_add_probe(name, probe, data);
- if (IS_ERR(old)) {
- mutex_unlock(&tracepoints_mutex);
- return PTR_ERR(old);
- }
- tracepoint_add_old_probes(old);
- mutex_unlock(&tracepoints_mutex);
- return 0;
-}
-EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
-
-/**
- * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect
- * @name: tracepoint name
- * @probe: probe function pointer
- *
- * caller must call tracepoint_probe_update_all()
- */
-int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
- void *data)
-{
- struct tracepoint_func *old;
-
- mutex_lock(&tracepoints_mutex);
- old = tracepoint_remove_probe(name, probe, data);
- if (IS_ERR(old)) {
- mutex_unlock(&tracepoints_mutex);
- return PTR_ERR(old);
- }
- tracepoint_add_old_probes(old);
- mutex_unlock(&tracepoints_mutex);
- return 0;
-}
-EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
-
-/**
- * tracepoint_probe_update_all - update tracepoints
- */
-void tracepoint_probe_update_all(void)
-{
- LIST_HEAD(release_probes);
- struct tp_probes *pos, *next;
-
- mutex_lock(&tracepoints_mutex);
- if (!need_update) {
- mutex_unlock(&tracepoints_mutex);
- return;
- }
- if (!list_empty(&old_probes))
- list_replace_init(&old_probes, &release_probes);
- need_update = 0;
- tracepoint_update_probes();
- mutex_unlock(&tracepoints_mutex);
- list_for_each_entry_safe(pos, next, &release_probes, u.list) {
- list_del(&pos->u.list);
- call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
- }
-}
-EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
-
-/**
- * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
- * @tracepoint: current tracepoints (in), next tracepoint (out)
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Returns whether a next tracepoint has been found (1) or not (0).
- * Will return the first tracepoint in the range if the input tracepoint is
- * NULL.
- */
-static int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
- struct tracepoint * const *begin, struct tracepoint * const *end)
-{
- if (!*tracepoint && begin != end) {
- *tracepoint = begin;
- return 1;
- }
- if (*tracepoint >= begin && *tracepoint < end)
- return 1;
- return 0;
-}
-
-#ifdef CONFIG_MODULES
-static void tracepoint_get_iter(struct tracepoint_iter *iter)
-{
- int found = 0;
- struct tp_module *iter_mod;
-
- /* Core kernel tracepoints */
- if (!iter->module) {
- found = tracepoint_get_iter_range(&iter->tracepoint,
- __start___tracepoints_ptrs,
- __stop___tracepoints_ptrs);
- if (found)
- goto end;
- }
- /* Tracepoints in modules */
- mutex_lock(&tracepoints_mutex);
- list_for_each_entry(iter_mod, &tracepoint_module_list, list) {
- /*
- * Sorted module list
- */
- if (iter_mod < iter->module)
- continue;
- else if (iter_mod > iter->module)
- iter->tracepoint = NULL;
- found = tracepoint_get_iter_range(&iter->tracepoint,
- iter_mod->tracepoints_ptrs,
- iter_mod->tracepoints_ptrs
- + iter_mod->num_tracepoints);
- if (found) {
- iter->module = iter_mod;
- break;
- }
- }
- mutex_unlock(&tracepoints_mutex);
-end:
- if (!found)
- tracepoint_iter_reset(iter);
-}
-#else /* CONFIG_MODULES */
-static void tracepoint_get_iter(struct tracepoint_iter *iter)
-{
- int found = 0;
-
- /* Core kernel tracepoints */
- found = tracepoint_get_iter_range(&iter->tracepoint,
- __start___tracepoints_ptrs,
- __stop___tracepoints_ptrs);
- if (!found)
- tracepoint_iter_reset(iter);
-}
-#endif /* CONFIG_MODULES */
-
-void tracepoint_iter_start(struct tracepoint_iter *iter)
-{
- tracepoint_get_iter(iter);
-}
-EXPORT_SYMBOL_GPL(tracepoint_iter_start);
-
-void tracepoint_iter_next(struct tracepoint_iter *iter)
-{
- iter->tracepoint++;
- /*
- * iter->tracepoint may be invalid because we blindly incremented it.
- * Make sure it is valid by marshalling on the tracepoints, getting the
- * tracepoints from following modules if necessary.
- */
- tracepoint_get_iter(iter);
-}
-EXPORT_SYMBOL_GPL(tracepoint_iter_next);
-
-void tracepoint_iter_stop(struct tracepoint_iter *iter)
-{
-}
-EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
-
-void tracepoint_iter_reset(struct tracepoint_iter *iter)
-{
-#ifdef CONFIG_MODULES
- iter->module = NULL;
-#endif /* CONFIG_MODULES */
- iter->tracepoint = NULL;
-}
-EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
#ifdef CONFIG_MODULES
bool trace_module_has_bad_taint(struct module *mod)
static int tracepoint_module_coming(struct module *mod)
{
- struct tp_module *tp_mod, *iter;
+ struct tp_module *tp_mod;
int ret = 0;
+ if (!mod->num_tracepoints)
+ return 0;
+
/*
* We skip modules that taint the kernel, especially those with different
* module headers (for forced load), to make sure we don't cause a crash.
}
tp_mod->num_tracepoints = mod->num_tracepoints;
tp_mod->tracepoints_ptrs = mod->tracepoints_ptrs;
-
- /*
- * tracepoint_module_list is kept sorted by struct module pointer
- * address for iteration on tracepoints from a seq_file that can release
- * the mutex between calls.
- */
- list_for_each_entry_reverse(iter, &tracepoint_module_list, list) {
- BUG_ON(iter == tp_mod); /* Should never be in the list twice */
- if (iter < tp_mod) {
- /* We belong to the location right after iter. */
- list_add(&tp_mod->list, &iter->list);
- goto module_added;
- }
- }
- /* We belong to the beginning of the list */
- list_add(&tp_mod->list, &tracepoint_module_list);
-module_added:
+ list_add_tail(&tp_mod->list, &tracepoint_module_list);
tracepoint_update_probe_range(mod->tracepoints_ptrs,
mod->tracepoints_ptrs + mod->num_tracepoints);
end:
{
struct tp_module *pos;
+ if (!mod->num_tracepoints)
+ return 0;
+
mutex_lock(&tracepoints_mutex);
tracepoint_update_probe_range(mod->tracepoints_ptrs,
mod->tracepoints_ptrs + mod->num_tracepoints);
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