summaryrefslogtreecommitdiff
path: root/kernel/marker.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/marker.c')
-rw-r--r--kernel/marker.c114
1 files changed, 100 insertions, 14 deletions
diff --git a/kernel/marker.c b/kernel/marker.c
index 2898b647d415..ea54f2647868 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -81,7 +81,7 @@ struct marker_entry {
* though the function pointer change and the marker enabling are two distinct
* operations that modifies the execution flow of preemptible code.
*/
-void __mark_empty_function(void *probe_private, void *call_private,
+notrace void __mark_empty_function(void *probe_private, void *call_private,
const char *fmt, va_list *args)
{
}
@@ -97,7 +97,8 @@ EXPORT_SYMBOL_GPL(__mark_empty_function);
* need to put a full smp_rmb() in this branch. This is why we do not use
* rcu_dereference() for the pointer read.
*/
-void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
+notrace void marker_probe_cb(const struct marker *mdata,
+ void *call_private, ...)
{
va_list args;
char ptype;
@@ -107,7 +108,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
* sure the teardown of the callbacks can be done correctly when they
* are in modules and they insure RCU read coherency.
*/
- rcu_read_lock_sched();
+ rcu_read_lock_sched_notrace();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -145,7 +146,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
va_end(args);
}
}
- rcu_read_unlock_sched();
+ rcu_read_unlock_sched_notrace();
}
EXPORT_SYMBOL_GPL(marker_probe_cb);
@@ -157,12 +158,13 @@ EXPORT_SYMBOL_GPL(marker_probe_cb);
*
* Should be connected to markers "MARK_NOARGS".
*/
-static void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
+static notrace void marker_probe_cb_noarg(const struct marker *mdata,
+ void *call_private, ...)
{
va_list args; /* not initialized */
char ptype;
- rcu_read_lock_sched();
+ rcu_read_lock_sched_notrace();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -195,7 +197,7 @@ static void marker_probe_cb_noarg(const struct marker *mdata, void *call_private
multi[i].func(multi[i].probe_private, call_private,
mdata->format, &args);
}
- rcu_read_unlock_sched();
+ rcu_read_unlock_sched_notrace();
}
static void free_old_closure(struct rcu_head *head)
@@ -477,7 +479,7 @@ static int marker_set_format(struct marker_entry *entry, const char *format)
static int set_marker(struct marker_entry *entry, struct marker *elem,
int active)
{
- int ret;
+ int ret = 0;
WARN_ON(strcmp(entry->name, elem->name) != 0);
if (entry->format) {
@@ -529,9 +531,40 @@ static int set_marker(struct marker_entry *entry, struct marker *elem,
*/
smp_wmb();
elem->ptype = entry->ptype;
+
+ if (elem->tp_name && (active ^ elem->state)) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+
+ if (active) {
+ /*
+ * try_module_get should always succeed because we hold
+ * lock_module() to get the tp_cb address.
+ */
+ ret = try_module_get(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ BUG_ON(!ret);
+ ret = tracepoint_probe_register_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ } else {
+ ret = tracepoint_probe_unregister_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ }
+ }
elem->state = active;
- return 0;
+ return ret;
}
/*
@@ -542,7 +575,24 @@ static int set_marker(struct marker_entry *entry, struct marker *elem,
*/
static void disable_marker(struct marker *elem)
{
+ int ret;
+
/* leave "call" as is. It is known statically. */
+ if (elem->tp_name && elem->state) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+ ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
+ elem->tp_cb);
+ WARN_ON(ret);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address((unsigned long)elem->tp_cb));
+ }
elem->state = 0;
elem->single.func = __mark_empty_function;
/* Update the function before setting the ptype */
@@ -606,6 +656,7 @@ static void marker_update_probes(void)
marker_update_probe_range(__start___markers, __stop___markers);
/* Markers in modules. */
module_update_markers();
+ tracepoint_probe_update_all();
}
/**
@@ -653,10 +704,11 @@ int marker_probe_register(const char *name, const char *format,
goto end;
}
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker(name);
- WARN_ON(!entry);
+ if (!entry)
+ goto end;
if (entry->rcu_pending)
rcu_barrier_sched();
entry->oldptr = old;
@@ -697,7 +749,7 @@ int marker_probe_unregister(const char *name,
rcu_barrier_sched();
old = marker_entry_remove_probe(entry, probe, probe_private);
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker(name);
if (!entry)
@@ -778,10 +830,11 @@ int marker_probe_unregister_private_data(marker_probe_func *probe,
rcu_barrier_sched();
old = marker_entry_remove_probe(entry, NULL, probe_private);
mutex_unlock(&markers_mutex);
- marker_update_probes(); /* may update entry */
+ marker_update_probes();
mutex_lock(&markers_mutex);
entry = get_marker_from_private_data(probe, probe_private);
- WARN_ON(!entry);
+ if (!entry)
+ goto end;
if (entry->rcu_pending)
rcu_barrier_sched();
entry->oldptr = old;
@@ -842,3 +895,36 @@ void *marker_get_private_data(const char *name, marker_probe_func *probe,
return ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL_GPL(marker_get_private_data);
+
+#ifdef CONFIG_MODULES
+
+int marker_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+
+ switch (val) {
+ case MODULE_STATE_COMING:
+ marker_update_probe_range(mod->markers,
+ mod->markers + mod->num_markers);
+ break;
+ case MODULE_STATE_GOING:
+ marker_update_probe_range(mod->markers,
+ mod->markers + mod->num_markers);
+ break;
+ }
+ return 0;
+}
+
+struct notifier_block marker_module_nb = {
+ .notifier_call = marker_module_notify,
+ .priority = 0,
+};
+
+static int init_markers(void)
+{
+ return register_module_notifier(&marker_module_nb);
+}
+__initcall(init_markers);
+
+#endif /* CONFIG_MODULES */
generated by cgit v1.2.3 (git 2.0.4) at 2025-05-11 21:32:36 +0000