#include <linux/tracepoint.h>
#include <linux/err.h>
#include <linux/slab.h>
+#include <linux/sched.h>
extern struct tracepoint __start___tracepoints[];
extern struct tracepoint __stop___tracepoints[];
/*
* Note about RCU :
- * It is used to to delay the free of multiple probes array until a quiescent
+ * It is used to delay the free of multiple probes array until a quiescent
* state is reached.
* Tracepoint entries modifications are protected by the tracepoints_mutex.
*/
struct tracepoint_entry {
struct hlist_node hlist;
- void **funcs;
+ struct tracepoint_func *funcs;
int refcount; /* Number of times armed. 0 if disarmed. */
char name[0];
};
struct tp_probes {
- struct rcu_head rcu;
- void *probes[0];
+ union {
+ struct rcu_head rcu;
+ struct list_head list;
+ } u;
+ struct tracepoint_func probes[0];
};
static inline void *allocate_probes(int count)
{
- struct tp_probes *p = kmalloc(count * sizeof(void *)
+ struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func)
+ sizeof(struct tp_probes), GFP_KERNEL);
return p == NULL ? NULL : p->probes;
}
static void rcu_free_old_probes(struct rcu_head *head)
{
- kfree(container_of(head, struct tp_probes, rcu));
+ kfree(container_of(head, struct tp_probes, u.rcu));
}
-static inline void release_probes(void *old)
+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(&tp_probes->rcu, rcu_free_old_probes);
+ call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
}
}
if (!tracepoint_debug || !entry->funcs)
return;
- for (i = 0; entry->funcs[i]; i++)
- printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
+ for (i = 0; entry->funcs[i].func; i++)
+ printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i].func);
}
-static void *
-tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
+static struct tracepoint_func *
+tracepoint_entry_add_probe(struct tracepoint_entry *entry,
+ void *probe, void *data)
{
int nr_probes = 0;
- void **old, **new;
+ struct tracepoint_func *old, *new;
WARN_ON(!probe);
old = entry->funcs;
if (old) {
/* (N -> N+1), (N != 0, 1) probes */
- for (nr_probes = 0; old[nr_probes]; nr_probes++)
- if (old[nr_probes] == probe)
+ for (nr_probes = 0; old[nr_probes].func; nr_probes++)
+ if (old[nr_probes].func == probe &&
+ old[nr_probes].data == data)
return ERR_PTR(-EEXIST);
}
/* + 2 : one for new probe, one for NULL func */
if (new == NULL)
return ERR_PTR(-ENOMEM);
if (old)
- memcpy(new, old, nr_probes * sizeof(void *));
- new[nr_probes] = probe;
- new[nr_probes + 1] = NULL;
+ memcpy(new, old, nr_probes * sizeof(struct tracepoint_func));
+ new[nr_probes].func = probe;
+ new[nr_probes].data = data;
+ new[nr_probes + 1].func = NULL;
entry->refcount = nr_probes + 1;
entry->funcs = new;
debug_print_probes(entry);
}
static void *
-tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
+tracepoint_entry_remove_probe(struct tracepoint_entry *entry,
+ void *probe, void *data)
{
int nr_probes = 0, nr_del = 0, i;
- void **old, **new;
+ struct tracepoint_func *old, *new;
old = entry->funcs;
debug_print_probes(entry);
/* (N -> M), (N > 1, M >= 0) probes */
- for (nr_probes = 0; old[nr_probes]; nr_probes++) {
- if ((!probe || old[nr_probes] == probe))
+ for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
+ if (!probe ||
+ (old[nr_probes].func == probe &&
+ old[nr_probes].data == data))
nr_del++;
}
new = allocate_probes(nr_probes - nr_del + 1);
if (new == NULL)
return ERR_PTR(-ENOMEM);
- for (i = 0; old[i]; i++)
- if ((probe && old[i] != probe))
+ for (i = 0; old[i].func; i++)
+ if (probe &&
+ (old[i].func != probe || old[i].data != data))
new[j++] = old[i];
- new[nr_probes - nr_del] = NULL;
+ new[nr_probes - nr_del].func = NULL;
entry->refcount = nr_probes - nr_del;
entry->funcs = new;
}
{
WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+ if (elem->regfunc && !elem->state && active)
+ elem->regfunc();
+ else if (elem->unregfunc && elem->state && !active)
+ elem->unregfunc();
+
/*
* rcu_assign_pointer has a smp_wmb() which makes sure that the new
* probe callbacks array is consistent before setting a pointer to it.
*/
static void disable_tracepoint(struct tracepoint *elem)
{
+ if (elem->unregfunc && elem->state)
+ elem->unregfunc();
+
elem->state = 0;
+ rcu_assign_pointer(elem->funcs, NULL);
}
/**
*
* Updates the probe callback corresponding to a range of tracepoints.
*/
-void tracepoint_update_probe_range(struct tracepoint *begin,
- struct tracepoint *end)
+void
+tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
{
struct tracepoint *iter;
struct tracepoint_entry *mark_entry;
+ if (!begin)
+ return;
+
mutex_lock(&tracepoints_mutex);
for (iter = begin; iter < end; iter++) {
mark_entry = get_tracepoint(iter->name);
module_update_tracepoints();
}
+static struct tracepoint_func *
+tracepoint_add_probe(const char *name, void *probe, void *data)
+{
+ struct tracepoint_entry *entry;
+ struct tracepoint_func *old;
+
+ entry = get_tracepoint(name);
+ if (!entry) {
+ entry = add_tracepoint(name);
+ if (IS_ERR(entry))
+ return (struct tracepoint_func *)entry;
+ }
+ old = tracepoint_entry_add_probe(entry, probe, data);
+ if (IS_ERR(old) && !entry->refcount)
+ remove_tracepoint(entry);
+ return old;
+}
+
/**
* tracepoint_probe_register - Connect a probe to a tracepoint
* @name: tracepoint name
* 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)
+int tracepoint_probe_register(const char *name, void *probe, void *data)
{
- struct tracepoint_entry *entry;
- int ret = 0;
- void *old;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- entry = get_tracepoint(name);
- if (!entry) {
- entry = add_tracepoint(name);
- if (IS_ERR(entry)) {
- ret = PTR_ERR(entry);
- goto end;
- }
- }
- old = tracepoint_entry_add_probe(entry, probe);
- if (IS_ERR(old)) {
- if (!entry->refcount)
- remove_tracepoint(entry);
- ret = PTR_ERR(old);
- goto end;
- }
+ old = tracepoint_add_probe(name, probe, data);
mutex_unlock(&tracepoints_mutex);
+ if (IS_ERR(old))
+ return PTR_ERR(old);
+
tracepoint_update_probes(); /* may update entry */
release_probes(old);
return 0;
-end:
- mutex_unlock(&tracepoints_mutex);
- return ret;
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
+static struct tracepoint_func *
+tracepoint_remove_probe(const char *name, void *probe, void *data)
+{
+ struct tracepoint_entry *entry;
+ struct tracepoint_func *old;
+
+ entry = get_tracepoint(name);
+ if (!entry)
+ return ERR_PTR(-ENOENT);
+ old = tracepoint_entry_remove_probe(entry, probe, data);
+ if (IS_ERR(old))
+ return old;
+ if (!entry->refcount)
+ remove_tracepoint(entry);
+ return old;
+}
+
/**
* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
* @name: tracepoint name
* itself uses stop_machine(), which insures that every preempt disabled section
* have finished.
*/
-int tracepoint_probe_unregister(const char *name, void *probe)
+int tracepoint_probe_unregister(const char *name, void *probe, void *data)
{
- struct tracepoint_entry *entry;
- void *old;
- int ret = -ENOENT;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- entry = get_tracepoint(name);
- if (!entry)
- goto end;
- old = tracepoint_entry_remove_probe(entry, probe);
- if (IS_ERR(old)) {
- ret = PTR_ERR(old);
- goto end;
- }
- if (!entry->refcount)
- remove_tracepoint(entry);
+ old = tracepoint_remove_probe(name, probe, data);
mutex_unlock(&tracepoints_mutex);
+ if (IS_ERR(old))
+ return PTR_ERR(old);
+
tracepoint_update_probes(); /* may update entry */
release_probes(old);
return 0;
-end:
- mutex_unlock(&tracepoints_mutex);
- return ret;
}
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;
+ mutex_unlock(&tracepoints_mutex);
+
+ tracepoint_update_probes();
+ 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)
iter->tracepoint = NULL;
}
EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
+
+#ifdef CONFIG_MODULES
+
+int tracepoint_module_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+
+ switch (val) {
+ case MODULE_STATE_COMING:
+ case MODULE_STATE_GOING:
+ tracepoint_update_probe_range(mod->tracepoints,
+ mod->tracepoints + mod->num_tracepoints);
+ break;
+ }
+ return 0;
+}
+
+struct notifier_block tracepoint_module_nb = {
+ .notifier_call = tracepoint_module_notify,
+ .priority = 0,
+};
+
+static int init_tracepoints(void)
+{
+ return register_module_notifier(&tracepoint_module_nb);
+}
+__initcall(init_tracepoints);
+
+#endif /* CONFIG_MODULES */
+
+#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
+
+/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
+static int sys_tracepoint_refcount;
+
+void syscall_regfunc(void)
+{
+ unsigned long flags;
+ struct task_struct *g, *t;
+
+ if (!sys_tracepoint_refcount) {
+ read_lock_irqsave(&tasklist_lock, flags);
+ do_each_thread(g, t) {
+ /* Skip kernel threads. */
+ if (t->mm)
+ set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
+ } while_each_thread(g, t);
+ read_unlock_irqrestore(&tasklist_lock, flags);
+ }
+ sys_tracepoint_refcount++;
+}
+
+void syscall_unregfunc(void)
+{
+ unsigned long flags;
+ struct task_struct *g, *t;
+
+ sys_tracepoint_refcount--;
+ if (!sys_tracepoint_refcount) {
+ read_lock_irqsave(&tasklist_lock, flags);
+ do_each_thread(g, t) {
+ clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT);
+ } while_each_thread(g, t);
+ read_unlock_irqrestore(&tasklist_lock, flags);
+ }
+}
+#endif
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff