#include <linux/tracepoint.h>
#include <linux/err.h>
#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/jump_label.h>
-extern struct tracepoint __start___tracepoints[];
-extern struct tracepoint __stop___tracepoints[];
+extern struct tracepoint * const __start___tracepoints_ptrs[];
+extern struct tracepoint * const __stop___tracepoints_ptrs[];
/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;
/*
* 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 rcu_head rcu;
struct list_head list;
} u;
- void *probes[0];
+ 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;
}
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,
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.
* is used.
*/
rcu_assign_pointer(elem->funcs, (*entry)->funcs);
- elem->state = active;
+ if (!elem->state && active) {
+ jump_label_enable(&elem->state);
+ elem->state = active;
+ } else if (elem->state && !active) {
+ jump_label_disable(&elem->state);
+ elem->state = active;
+ }
}
/*
*/
static void disable_tracepoint(struct tracepoint *elem)
{
- elem->state = 0;
+ if (elem->unregfunc && elem->state)
+ elem->unregfunc();
+
+ if (elem->state) {
+ jump_label_disable(&elem->state);
+ 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 * const *begin,
+ struct tracepoint * const *end)
{
- struct tracepoint *iter;
+ struct tracepoint * const *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);
+ mark_entry = get_tracepoint((*iter)->name);
if (mark_entry) {
- set_tracepoint(&mark_entry, iter,
+ set_tracepoint(&mark_entry, *iter,
!!mark_entry->refcount);
} else {
- disable_tracepoint(iter);
+ disable_tracepoint(*iter);
}
}
mutex_unlock(&tracepoints_mutex);
static void tracepoint_update_probes(void)
{
/* Core kernel tracepoints */
- tracepoint_update_probe_range(__start___tracepoints,
- __stop___tracepoints);
+ tracepoint_update_probe_range(__start___tracepoints_ptrs,
+ __stop___tracepoints_ptrs);
/* tracepoints in modules. */
module_update_tracepoints();
}
-static void *tracepoint_add_probe(const char *name, void *probe)
+static struct tracepoint_func *
+tracepoint_add_probe(const char *name, void *probe, void *data)
{
struct tracepoint_entry *entry;
- void *old;
+ struct tracepoint_func *old;
entry = get_tracepoint(name);
if (!entry) {
entry = add_tracepoint(name);
if (IS_ERR(entry))
- return entry;
+ return (struct tracepoint_func *)entry;
}
- old = tracepoint_entry_add_probe(entry, probe);
+ old = tracepoint_entry_add_probe(entry, probe, data);
if (IS_ERR(old) && !entry->refcount)
remove_tracepoint(entry);
return old;
* 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)
{
- void *old;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- old = tracepoint_add_probe(name, probe);
+ old = tracepoint_add_probe(name, probe, data);
mutex_unlock(&tracepoints_mutex);
if (IS_ERR(old))
return PTR_ERR(old);
}
EXPORT_SYMBOL_GPL(tracepoint_probe_register);
-static void *tracepoint_remove_probe(const char *name, void *probe)
+static struct tracepoint_func *
+tracepoint_remove_probe(const char *name, void *probe, void *data)
{
struct tracepoint_entry *entry;
- void *old;
+ struct tracepoint_func *old;
entry = get_tracepoint(name);
if (!entry)
return ERR_PTR(-ENOENT);
- old = tracepoint_entry_remove_probe(entry, probe);
+ old = tracepoint_entry_remove_probe(entry, probe, data);
if (IS_ERR(old))
return old;
if (!entry->refcount)
* 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)
{
- void *old;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- old = tracepoint_remove_probe(name, probe);
+ old = tracepoint_remove_probe(name, probe, data);
mutex_unlock(&tracepoints_mutex);
if (IS_ERR(old))
return PTR_ERR(old);
*
* caller must call tracepoint_probe_update_all()
*/
-int tracepoint_probe_register_noupdate(const char *name, void *probe)
+int tracepoint_probe_register_noupdate(const char *name, void *probe,
+ void *data)
{
- void *old;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- old = tracepoint_add_probe(name, probe);
+ old = tracepoint_add_probe(name, probe, data);
if (IS_ERR(old)) {
mutex_unlock(&tracepoints_mutex);
return PTR_ERR(old);
*
* caller must call tracepoint_probe_update_all()
*/
-int tracepoint_probe_unregister_noupdate(const char *name, void *probe)
+int tracepoint_probe_unregister_noupdate(const char *name, void *probe,
+ void *data)
{
- void *old;
+ struct tracepoint_func *old;
mutex_lock(&tracepoints_mutex);
- old = tracepoint_remove_probe(name, probe);
+ old = tracepoint_remove_probe(name, probe, data);
if (IS_ERR(old)) {
mutex_unlock(&tracepoints_mutex);
return PTR_ERR(old);
* Will return the first tracepoint in the range if the input tracepoint is
* NULL.
*/
-int tracepoint_get_iter_range(struct tracepoint **tracepoint,
- struct tracepoint *begin, struct tracepoint *end)
+int tracepoint_get_iter_range(struct tracepoint * const **tracepoint,
+ struct tracepoint * const *begin, struct tracepoint * const *end)
{
if (!*tracepoint && begin != end) {
*tracepoint = begin;
/* Core kernel tracepoints */
if (!iter->module) {
found = tracepoint_get_iter_range(&iter->tracepoint,
- __start___tracepoints, __stop___tracepoints);
+ __start___tracepoints_ptrs,
+ __stop___tracepoints_ptrs);
if (found)
goto end;
}
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_ptrs,
+ mod->tracepoints_ptrs + 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
projects / linux-flexiantxendom0-natty.git / blobdiff