ust: add tracepoint.{c,h} from kernel
authorPierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Tue, 3 Mar 2009 17:14:05 +0000 (12:14 -0500)
committerPierre-Marc Fournier <pierre-marc.fournier@polymtl.ca>
Tue, 3 Mar 2009 17:14:05 +0000 (12:14 -0500)
libmarkers/tracepoint.c [new file with mode: 0644]
libmarkers/tracepoint.h [new file with mode: 0644]

diff --git a/libmarkers/tracepoint.c b/libmarkers/tracepoint.c
new file mode 100644 (file)
index 0000000..2d67de0
--- /dev/null
@@ -0,0 +1,580 @@
+/*
+ * Copyright (C) 2008 Mathieu Desnoyers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/jhash.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/tracepoint.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/immediate.h>
+
+extern struct tracepoint __start___tracepoints[];
+extern struct tracepoint __stop___tracepoints[];
+
+/* Set to 1 to enable tracepoint debug output */
+static const int tracepoint_debug;
+
+/*
+ * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
+ * builtin and module tracepoints and the hash table.
+ */
+static DEFINE_MUTEX(tracepoints_mutex);
+
+/*
+ * Tracepoint hash table, containing the active tracepoints.
+ * Protected by tracepoints_mutex.
+ */
+#define TRACEPOINT_HASH_BITS 6
+#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
+static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
+
+/*
+ * Note about RCU :
+ * It is used to 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;
+       int refcount;   /* Number of times armed. 0 if disarmed. */
+       char name[0];
+};
+
+struct tp_probes {
+       union {
+               struct rcu_head rcu;
+               struct list_head list;
+       } u;
+       void *probes[0];
+};
+
+static inline void *allocate_probes(int count)
+{
+       struct tp_probes *p  = kmalloc(count * sizeof(void *)
+                       + 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, u.rcu));
+}
+
+static inline void release_probes(void *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);
+       }
+}
+
+static void debug_print_probes(struct tracepoint_entry *entry)
+{
+       int i;
+
+       if (!tracepoint_debug || !entry->funcs)
+               return;
+
+       for (i = 0; entry->funcs[i]; i++)
+               printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
+}
+
+static void *
+tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
+{
+       int nr_probes = 0;
+       void **old, **new;
+
+       WARN_ON(!probe);
+
+       debug_print_probes(entry);
+       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)
+                               return ERR_PTR(-EEXIST);
+       }
+       /* + 2 : one for new probe, one for NULL func */
+       new = allocate_probes(nr_probes + 2);
+       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;
+       entry->refcount = nr_probes + 1;
+       entry->funcs = new;
+       debug_print_probes(entry);
+       return old;
+}
+
+static void *
+tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
+{
+       int nr_probes = 0, nr_del = 0, i;
+       void **old, **new;
+
+       old = entry->funcs;
+
+       if (!old)
+               return ERR_PTR(-ENOENT);
+
+       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))
+                       nr_del++;
+       }
+
+       if (nr_probes - nr_del == 0) {
+               /* N -> 0, (N > 1) */
+               entry->funcs = NULL;
+               entry->refcount = 0;
+               debug_print_probes(entry);
+               return old;
+       } else {
+               int j = 0;
+               /* N -> M, (N > 1, M > 0) */
+               /* + 1 for NULL */
+               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))
+                               new[j++] = old[i];
+               new[nr_probes - nr_del] = NULL;
+               entry->refcount = nr_probes - nr_del;
+               entry->funcs = new;
+       }
+       debug_print_probes(entry);
+       return old;
+}
+
+/*
+ * Get tracepoint if the tracepoint is present in the tracepoint hash table.
+ * Must be called with tracepoints_mutex held.
+ * Returns NULL if not present.
+ */
+static struct tracepoint_entry *get_tracepoint(const char *name)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct tracepoint_entry *e;
+       u32 hash = jhash(name, strlen(name), 0);
+
+       head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name))
+                       return e;
+       }
+       return NULL;
+}
+
+/*
+ * Add the tracepoint to the tracepoint hash table. Must be called with
+ * tracepoints_mutex held.
+ */
+static struct tracepoint_entry *add_tracepoint(const char *name)
+{
+       struct hlist_head *head;
+       struct hlist_node *node;
+       struct tracepoint_entry *e;
+       size_t name_len = strlen(name) + 1;
+       u32 hash = jhash(name, name_len-1, 0);
+
+       head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
+       hlist_for_each_entry(e, node, head, hlist) {
+               if (!strcmp(name, e->name)) {
+                       printk(KERN_NOTICE
+                               "tracepoint %s busy\n", name);
+                       return ERR_PTR(-EEXIST);        /* Already there */
+               }
+       }
+       /*
+        * Using kmalloc here to allocate a variable length element. Could
+        * cause some memory fragmentation if overused.
+        */
+       e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
+       if (!e)
+               return ERR_PTR(-ENOMEM);
+       memcpy(&e->name[0], name, name_len);
+       e->funcs = NULL;
+       e->refcount = 0;
+       hlist_add_head(&e->hlist, head);
+       return e;
+}
+
+/*
+ * Remove the tracepoint from the tracepoint hash table. Must be called with
+ * mutex_lock held.
+ */
+static inline void remove_tracepoint(struct tracepoint_entry *e)
+{
+       hlist_del(&e->hlist);
+       kfree(e);
+}
+
+/*
+ * Sets the probe callback corresponding to one tracepoint.
+ */
+static void set_tracepoint(struct tracepoint_entry **entry,
+       struct tracepoint *elem, int active)
+{
+       WARN_ON(strcmp((*entry)->name, elem->name) != 0);
+
+       /*
+        * rcu_assign_pointer has a smp_wmb() which makes sure that the new
+        * probe callbacks array is consistent before setting a pointer to it.
+        * This array is referenced by __DO_TRACE from
+        * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
+        * is used.
+        */
+       rcu_assign_pointer(elem->funcs, (*entry)->funcs);
+       elem->state__imv = active;
+}
+
+/*
+ * Disable a tracepoint and its probe callback.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
+ */
+static void disable_tracepoint(struct tracepoint *elem)
+{
+       elem->state__imv = 0;
+       rcu_assign_pointer(elem->funcs, NULL);
+}
+
+/**
+ * tracepoint_update_probe_range - Update a probe range
+ * @begin: beginning of the range
+ * @end: end of the range
+ *
+ * Updates the probe callback corresponding to a range of tracepoints.
+ */
+void tracepoint_update_probe_range(struct tracepoint *begin,
+       struct tracepoint *end)
+{
+       struct tracepoint *iter;
+       struct tracepoint_entry *mark_entry;
+
+       mutex_lock(&tracepoints_mutex);
+       for (iter = begin; iter < end; iter++) {
+               mark_entry = get_tracepoint(iter->name);
+               if (mark_entry) {
+                       set_tracepoint(&mark_entry, iter,
+                                       !!mark_entry->refcount);
+               } else {
+                       disable_tracepoint(iter);
+               }
+       }
+       mutex_unlock(&tracepoints_mutex);
+}
+
+/*
+ * Update probes, removing the faulty probes.
+ */
+static void tracepoint_update_probes(void)
+{
+       /* Core kernel tracepoints */
+       tracepoint_update_probe_range(__start___tracepoints,
+               __stop___tracepoints);
+       /* tracepoints in modules. */
+       module_update_tracepoints();
+       /* Update immediate values */
+       core_imv_update();
+       module_imv_update();
+}
+
+static void *tracepoint_add_probe(const char *name, void *probe)
+{
+       struct tracepoint_entry *entry;
+       void *old;
+
+       entry = get_tracepoint(name);
+       if (!entry) {
+               entry = add_tracepoint(name);
+               if (IS_ERR(entry))
+                       return entry;
+       }
+       old = tracepoint_entry_add_probe(entry, probe);
+       if (IS_ERR(old) && !entry->refcount)
+               remove_tracepoint(entry);
+       return old;
+}
+
+/**
+ * tracepoint_probe_register -  Connect a probe to a tracepoint
+ * @name: tracepoint name
+ * @probe: probe handler
+ *
+ * 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 *old;
+
+       mutex_lock(&tracepoints_mutex);
+       old = tracepoint_add_probe(name, probe);
+       mutex_unlock(&tracepoints_mutex);
+       if (IS_ERR(old))
+               return PTR_ERR(old);
+
+       tracepoint_update_probes();             /* may update entry */
+       release_probes(old);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(tracepoint_probe_register);
+
+static void *tracepoint_remove_probe(const char *name, void *probe)
+{
+       struct tracepoint_entry *entry;
+       void *old;
+
+       entry = get_tracepoint(name);
+       if (!entry)
+               return ERR_PTR(-ENOENT);
+       old = tracepoint_entry_remove_probe(entry, probe);
+       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
+ * @probe: probe function pointer
+ *
+ * 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
+ * itself uses stop_machine(), which insures that every preempt disabled section
+ * have finished.
+ */
+int tracepoint_probe_unregister(const char *name, void *probe)
+{
+       void *old;
+
+       mutex_lock(&tracepoints_mutex);
+       old = tracepoint_remove_probe(name, probe);
+       mutex_unlock(&tracepoints_mutex);
+       if (IS_ERR(old))
+               return PTR_ERR(old);
+
+       tracepoint_update_probes();             /* may update entry */
+       release_probes(old);
+       return 0;
+}
+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 *old;
+
+       mutex_lock(&tracepoints_mutex);
+       old = tracepoint_add_probe(name, probe);
+       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 *old;
+
+       mutex_lock(&tracepoints_mutex);
+       old = tracepoint_remove_probe(name, probe);
+       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)
+ * @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.
+ */
+int tracepoint_get_iter_range(struct tracepoint **tracepoint,
+       struct tracepoint *begin, struct tracepoint *end)
+{
+       if (!*tracepoint && begin != end) {
+               *tracepoint = begin;
+               return 1;
+       }
+       if (*tracepoint >= begin && *tracepoint < end)
+               return 1;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
+
+static void tracepoint_get_iter(struct tracepoint_iter *iter)
+{
+       int found = 0;
+
+       /* Core kernel tracepoints */
+       if (!iter->module) {
+               found = tracepoint_get_iter_range(&iter->tracepoint,
+                               __start___tracepoints, __stop___tracepoints);
+               if (found)
+                       goto end;
+       }
+       /* tracepoints in modules. */
+       found = module_get_iter_tracepoints(iter);
+end:
+       if (!found)
+               tracepoint_iter_reset(iter);
+}
+
+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)
+{
+       iter->module = NULL;
+       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:
+               tracepoint_update_probe_range(mod->tracepoints,
+                       mod->tracepoints + mod->num_tracepoints);
+               break;
+       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 */
diff --git a/libmarkers/tracepoint.h b/libmarkers/tracepoint.h
new file mode 100644 (file)
index 0000000..860b674
--- /dev/null
@@ -0,0 +1,177 @@
+#ifndef _LINUX_TRACEPOINT_H
+#define _LINUX_TRACEPOINT_H
+
+/*
+ * Kernel Tracepoint API.
+ *
+ * See Documentation/tracepoint.txt.
+ *
+ * (C) Copyright 2008 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * Heavily inspired from the Linux Kernel Markers.
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/immediate.h>
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+
+struct module;
+struct tracepoint;
+
+struct tracepoint {
+       const char *name;               /* Tracepoint name */
+       DEFINE_IMV(char, state);        /* State. */
+       void **funcs;
+} __attribute__((aligned(32)));                /*
+                                        * Aligned on 32 bytes because it is
+                                        * globally visible and gcc happily
+                                        * align these on the structure size.
+                                        * Keep in sync with vmlinux.lds.h.
+                                        */
+
+#define TPPROTO(args...)       args
+#define TPARGS(args...)                args
+
+#ifdef CONFIG_TRACEPOINTS
+
+/*
+ * it_func[0] is never NULL because there is at least one element in the array
+ * when the array itself is non NULL.
+ */
+#define __DO_TRACE(tp, proto, args)                                    \
+       do {                                                            \
+               void **it_func;                                         \
+                                                                       \
+               rcu_read_lock_sched_notrace();                          \
+               it_func = rcu_dereference((tp)->funcs);                 \
+               if (it_func) {                                          \
+                       do {                                            \
+                               ((void(*)(proto))(*it_func))(args);     \
+                       } while (*(++it_func));                         \
+               }                                                       \
+               rcu_read_unlock_sched_notrace();                        \
+       } while (0)
+
+#define __CHECK_TRACE(name, generic, proto, args)                      \
+       do {                                                            \
+               if (!generic) {                                         \
+                       if (unlikely(imv_read(__tracepoint_##name.state))) \
+                               __DO_TRACE(&__tracepoint_##name,        \
+                                       TPPROTO(proto), TPARGS(args));  \
+               } else {                                                \
+                       if (unlikely(_imv_read(__tracepoint_##name.state))) \
+                               __DO_TRACE(&__tracepoint_##name,        \
+                                       TPPROTO(proto), TPARGS(args));  \
+               }                                                       \
+       } while (0)
+
+/*
+ * Make sure the alignment of the structure in the __tracepoints section will
+ * not add unwanted padding between the beginning of the section and the
+ * structure. Force alignment to the same alignment as the section start.
+ *
+ * The "generic" argument, passed to the declared __trace_##name inline
+ * function controls which tracepoint enabling mechanism must be used.
+ * If generic is true, a variable read is used.
+ * If generic is false, immediate values are used.
+ */
+#define DECLARE_TRACE(name, proto, args)                               \
+       extern struct tracepoint __tracepoint_##name;                   \
+       static inline void trace_##name(proto)                          \
+       {                                                               \
+               __CHECK_TRACE(name, 0, TPPROTO(proto), TPARGS(args));   \
+       }                                                               \
+       static inline void _trace_##name(proto)                         \
+       {                                                               \
+               __CHECK_TRACE(name, 1, TPPROTO(proto), TPARGS(args));   \
+       }                                                               \
+       static inline int register_trace_##name(void (*probe)(proto))   \
+       {                                                               \
+               return tracepoint_probe_register(#name, (void *)probe); \
+       }                                                               \
+       static inline int unregister_trace_##name(void (*probe)(proto)) \
+       {                                                               \
+               return tracepoint_probe_unregister(#name, (void *)probe);\
+       }
+
+#define DEFINE_TRACE(name)                                             \
+       static const char __tpstrtab_##name[]                           \
+       __attribute__((section("__tracepoints_strings"))) = #name;      \
+       struct tracepoint __tracepoint_##name                           \
+       __attribute__((section("__tracepoints"), aligned(32))) =        \
+               { __tpstrtab_##name, 0, NULL }
+
+#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)                             \
+       EXPORT_SYMBOL_GPL(__tracepoint_##name)
+#define EXPORT_TRACEPOINT_SYMBOL(name)                                 \
+       EXPORT_SYMBOL(__tracepoint_##name)
+
+extern void tracepoint_update_probe_range(struct tracepoint *begin,
+       struct tracepoint *end);
+
+#else /* !CONFIG_TRACEPOINTS */
+#define DECLARE_TRACE(name, proto, args)                               \
+       static inline void trace_##name(proto)                          \
+       { }                                                             \
+       static inline void _trace_##name(proto)                         \
+       { }                                                             \
+       static inline int register_trace_##name(void (*probe)(proto))   \
+       {                                                               \
+               return -ENOSYS;                                         \
+       }                                                               \
+       static inline int unregister_trace_##name(void (*probe)(proto)) \
+       {                                                               \
+               return -ENOSYS;                                         \
+       }
+
+#define DEFINE_TRACE(name)
+#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
+#define EXPORT_TRACEPOINT_SYMBOL(name)
+
+static inline void tracepoint_update_probe_range(struct tracepoint *begin,
+       struct tracepoint *end)
+{ }
+#endif /* CONFIG_TRACEPOINTS */
+
+/*
+ * Connect a probe to a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_register(const char *name, void *probe);
+
+/*
+ * Disconnect a probe from a tracepoint.
+ * Internal API, should not be used directly.
+ */
+extern int tracepoint_probe_unregister(const char *name, void *probe);
+
+extern int tracepoint_probe_register_noupdate(const char *name, void *probe);
+extern int tracepoint_probe_unregister_noupdate(const char *name, void *probe);
+extern void tracepoint_probe_update_all(void);
+
+struct tracepoint_iter {
+       struct module *module;
+       struct tracepoint *tracepoint;
+};
+
+extern void tracepoint_iter_start(struct tracepoint_iter *iter);
+extern void tracepoint_iter_next(struct tracepoint_iter *iter);
+extern void tracepoint_iter_stop(struct tracepoint_iter *iter);
+extern void tracepoint_iter_reset(struct tracepoint_iter *iter);
+extern int tracepoint_get_iter_range(struct tracepoint **tracepoint,
+       struct tracepoint *begin, struct tracepoint *end);
+
+/*
+ * tracepoint_synchronize_unregister must be called between the last tracepoint
+ * probe unregistration and the end of module exit to make sure there is no
+ * caller executing a probe when it is freed.
+ */
+static inline void tracepoint_synchronize_unregister(void)
+{
+       synchronize_sched();
+}
+
+#endif
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