[lttng-ust.git] / libust / tracepoint.c

/*
 * Copyright (C) 2008 Mathieu Desnoyers
 * Copyright (C) 2009 Pierre-Marc Fournier
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Ported to userspace by Pierre-Marc Fournier.
 */

//ust// #include <linux/module.h>
//ust// #include <linux/mutex.h>
//ust// #include <linux/types.h>
//ust// #include <linux/jhash.h>
//ust// #include <linux/list.h>
//ust// #include <linux/rcupdate.h>
//ust// #include <linux/tracepoint.h>
//ust// #include <linux/err.h>
//ust// #include <linux/slab.h>
//ust// #include <linux/immediate.h>

#include <errno.h>

#include "kernelcompat.h"
#include "tracepoint.h"
#include "usterr.h"
#include "list.h"
#include "urcu.h"

//extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
//extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));

/* Set to 1 to enable tracepoint debug output */
static const int tracepoint_debug;

/* libraries that contain tracepoints (struct tracepoint_lib) */
static LIST_HEAD(libs);

/*
 * 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 {
//ust//		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;
}

//ust// static void rcu_free_old_probes(struct rcu_head *head)
//ust// {
//ust// 	kfree(container_of(head, struct tp_probes, u.rcu));
//ust// }

static inline void release_probes(void *old)
{
	if (old) {
		struct tp_probes *tp_probes = container_of(old,
			struct tp_probes, probes[0]);
//ust//		call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
		synchronize_rcu();
		kfree(tp_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 */
//ust//	tracepoint_update_probe_range(__start___tracepoints,
//ust//		__stop___tracepoints);
	/* tracepoints in modules. */
	lib_update_tracepoints();
	/* Update immediate values */
	core_imv_update();
//ust//	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;
}
//ust// 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;
}
//ust// 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;
}
//ust// 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;
}
//ust// 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);
//ust//		call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
		synchronize_rcu();
		kfree(pos);
	}
}
//ust// 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;
}
//ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);

static void tracepoint_get_iter(struct tracepoint_iter *iter)
{
	int found = 0;

//ust//	/* Core kernel tracepoints */
//ust//	if (!iter->module) {
//ust//		found = tracepoint_get_iter_range(&iter->tracepoint,
//ust//				__start___tracepoints, __stop___tracepoints);
//ust//		if (found)
//ust//			goto end;
//ust//	}
	/* tracepoints in libs. */
	found = lib_get_iter_tracepoints(iter);
end:
	if (!found)
		tracepoint_iter_reset(iter);
}

void tracepoint_iter_start(struct tracepoint_iter *iter)
{
	tracepoint_get_iter(iter);
}
//ust// 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);
}
//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);

void tracepoint_iter_stop(struct tracepoint_iter *iter)
{
}
//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);

void tracepoint_iter_reset(struct tracepoint_iter *iter)
{
//ust//	iter->module = NULL;
	iter->tracepoint = NULL;
}
//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);

//ust// #ifdef CONFIG_MODULES

//ust// int tracepoint_module_notify(struct notifier_block *self,
//ust// 			     unsigned long val, void *data)
//ust// {
//ust// 	struct module *mod = data;
//ust// 
//ust// 	switch (val) {
//ust// 	case MODULE_STATE_COMING:
//ust// 		tracepoint_update_probe_range(mod->tracepoints,
//ust// 			mod->tracepoints + mod->num_tracepoints);
//ust// 		break;
//ust// 	case MODULE_STATE_GOING:
//ust// 		tracepoint_update_probe_range(mod->tracepoints,
//ust// 			mod->tracepoints + mod->num_tracepoints);
//ust// 		break;
//ust// 	}
//ust// 	return 0;
//ust// }

//ust// struct notifier_block tracepoint_module_nb = {
//ust// 	.notifier_call = tracepoint_module_notify,
//ust// 	.priority = 0,
//ust// };

//ust// static int init_tracepoints(void)
//ust// {
//ust// 	return register_module_notifier(&tracepoint_module_nb);
//ust// }
//ust// __initcall(init_tracepoints);

//ust// #endif /* CONFIG_MODULES */

/*
 * Returns 0 if current not found.
 * Returns 1 if current found.
 */
int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
{
	struct tracepoint_lib *iter_lib;
	int found = 0;

//ust//	mutex_lock(&module_mutex);
	list_for_each_entry(iter_lib, &libs, list) {
		if (iter_lib < iter->lib)
			continue;
		else if (iter_lib > iter->lib)
			iter->tracepoint = NULL;
		found = marker_get_iter_range(&iter->tracepoint,
			iter_lib->tracepoints_start,
			iter_lib->tracepoints_start + iter_lib->tracepoints_count);
		if (found) {
			iter->lib = iter_lib;
			break;
		}
	}
//ust//	mutex_unlock(&module_mutex);
	return found;
}

void lib_update_tracepoints(void)
{
	struct tracepoint_lib *lib;

//ust//	mutex_lock(&module_mutex);
	list_for_each_entry(lib, &libs, list)
		tracepoint_update_probe_range(lib->tracepoints_start,
				lib->tracepoints_start + lib->tracepoints_count);
//ust//	mutex_unlock(&module_mutex);
}

static void (*new_tracepoint_cb)(struct tracepoint *) = NULL;

void tracepoint_set_new_tracepoint_cb(void (*cb)(struct tracepoint *))
{
	new_tracepoint_cb = cb;
}

static void new_tracepoints(struct tracepoint *start, struct tracepoint *end)
{
	if(new_tracepoint_cb) {
		struct tracepoint *t;
		for(t=start; t < end; t++) {
			new_tracepoint_cb(t);
		}
	}
}

int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
{
	struct tracepoint_lib *pl;

	pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));

	pl->tracepoints_start = tracepoints_start;
	pl->tracepoints_count = tracepoints_count;

	/* FIXME: maybe protect this with its own mutex? */
	mutex_lock(&tracepoints_mutex);
	list_add(&pl->list, &libs);
	mutex_unlock(&tracepoints_mutex);

	new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);

	/* FIXME: update just the loaded lib */
	lib_update_tracepoints();

	DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
	
	return 0;
}

int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
{
	/*FIXME: implement; but before implementing, tracepoint_register_lib must
          have appropriate locking. */

	return 0;
}
Commit	Line	Data
f99be407 PMF	1	/*
f99be407 PMF	2	* Copyright (C) 2008 Mathieu Desnoyers
1f8b0dff	3	* Copyright (C) 2009 Pierre-Marc Fournier
f99be407	4	*
1f8b0dff PMF	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version 2
	8	* of the License, or (at your option) any later version.
f99be407 PMF	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to the Free Software
1f8b0dff PMF	17	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	18	*
	19	* Ported to userspace by Pierre-Marc Fournier.
f99be407	20	*/
1f8b0dff	21
474d745f PMF	22	//ust// #include <linux/module.h>
	23	//ust// #include <linux/mutex.h>
	24	//ust// #include <linux/types.h>
	25	//ust// #include <linux/jhash.h>
	26	//ust// #include <linux/list.h>
	27	//ust// #include <linux/rcupdate.h>
	28	//ust// #include <linux/tracepoint.h>
	29	//ust// #include <linux/err.h>
	30	//ust// #include <linux/slab.h>
	31	//ust// #include <linux/immediate.h>
	32
	33	#include <errno.h>
	34
	35	#include "kernelcompat.h"
	36	#include "tracepoint.h"
	37	#include "usterr.h"
	38	#include "list.h"
6cb88bc0	39	#include "urcu.h"
474d745f PMF	40
	41	//extern struct tracepoint __start___tracepoints[] __attribute__((visibility("hidden")));
	42	//extern struct tracepoint __stop___tracepoints[] __attribute__((visibility("hidden")));
f99be407 PMF	43
	44	/* Set to 1 to enable tracepoint debug output */
	45	static const int tracepoint_debug;
	46
474d745f PMF	47	/* libraries that contain tracepoints (struct tracepoint_lib) */
	48	static LIST_HEAD(libs);
	49
f99be407 PMF	50	/*
	51	* tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
	52	* builtin and module tracepoints and the hash table.
	53	*/
	54	static DEFINE_MUTEX(tracepoints_mutex);
	55
	56	/*
	57	* Tracepoint hash table, containing the active tracepoints.
	58	* Protected by tracepoints_mutex.
	59	*/
	60	#define TRACEPOINT_HASH_BITS 6
	61	#define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
	62	static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
	63
	64	/*
	65	* Note about RCU :
	66	* It is used to to delay the free of multiple probes array until a quiescent
	67	* state is reached.
	68	* Tracepoint entries modifications are protected by the tracepoints_mutex.
	69	*/
	70	struct tracepoint_entry {
	71	struct hlist_node hlist;
	72	void **funcs;
	73	int refcount; /* Number of times armed. 0 if disarmed. */
	74	char name[0];
	75	};
	76
	77	struct tp_probes {
	78	union {
474d745f	79	//ust// struct rcu_head rcu;
f99be407 PMF	80	struct list_head list;
	81	} u;
	82	void *probes[0];
	83	};
	84
	85	static inline void *allocate_probes(int count)
	86	{
	87	struct tp_probes p = kmalloc(count sizeof(void *)
	88	+ sizeof(struct tp_probes), GFP_KERNEL);
	89	return p == NULL ? NULL : p->probes;
	90	}
	91
474d745f PMF	92	//ust// static void rcu_free_old_probes(struct rcu_head *head)
	93	//ust// {
	94	//ust// kfree(container_of(head, struct tp_probes, u.rcu));
	95	//ust// }
f99be407 PMF	96
	97	static inline void release_probes(void *old)
	98	{
	99	if (old) {
	100	struct tp_probes *tp_probes = container_of(old,
	101	struct tp_probes, probes[0]);
474d745f PMF	102	//ust// call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes);
	103	synchronize_rcu();
	104	kfree(tp_probes);
f99be407 PMF	105	}
	106	}
	107
	108	static void debug_print_probes(struct tracepoint_entry *entry)
	109	{
	110	int i;
	111
	112	if (!tracepoint_debug \|\| !entry->funcs)
	113	return;
	114
	115	for (i = 0; entry->funcs[i]; i++)
	116	printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
	117	}
	118
	119	static void *
	120	tracepoint_entry_add_probe(struct tracepoint_entry entry, void probe)
	121	{
	122	int nr_probes = 0;
	123	void old, new;
	124
	125	WARN_ON(!probe);
	126
	127	debug_print_probes(entry);
	128	old = entry->funcs;
	129	if (old) {
	130	/* (N -> N+1), (N != 0, 1) probes */
	131	for (nr_probes = 0; old[nr_probes]; nr_probes++)
	132	if (old[nr_probes] == probe)
	133	return ERR_PTR(-EEXIST);
	134	}
	135	/* + 2 : one for new probe, one for NULL func */
	136	new = allocate_probes(nr_probes + 2);
	137	if (new == NULL)
	138	return ERR_PTR(-ENOMEM);
	139	if (old)
	140	memcpy(new, old, nr_probes * sizeof(void *));
	141	new[nr_probes] = probe;
	142	new[nr_probes + 1] = NULL;
	143	entry->refcount = nr_probes + 1;
	144	entry->funcs = new;
	145	debug_print_probes(entry);
	146	return old;
	147	}
	148
	149	static void *
	150	tracepoint_entry_remove_probe(struct tracepoint_entry entry, void probe)
	151	{
	152	int nr_probes = 0, nr_del = 0, i;
	153	void old, new;
	154
	155	old = entry->funcs;
	156
	157	if (!old)
	158	return ERR_PTR(-ENOENT);
	159
	160	debug_print_probes(entry);
	161	/* (N -> M), (N > 1, M >= 0) probes */
	162	for (nr_probes = 0; old[nr_probes]; nr_probes++) {
	163	if ((!probe \|\| old[nr_probes] == probe))
	164	nr_del++;
	165	}
	166
	167	if (nr_probes - nr_del == 0) {
	168	/* N -> 0, (N > 1) */
169	entry->funcs = NULL;
170	entry->refcount = 0;
171	debug_print_probes(entry);
172	return old;
173	} else {
174	int j = 0;
175	/* N -> M, (N > 1, M > 0) */
176	/* + 1 for NULL */
177	new = allocate_probes(nr_probes - nr_del + 1);
178	if (new == NULL)
179	return ERR_PTR(-ENOMEM);
180	for (i = 0; old[i]; i++)
181	if ((probe && old[i] != probe))
182	new[j++] = old[i];
183	new[nr_probes - nr_del] = NULL;
184	entry->refcount = nr_probes - nr_del;
185	entry->funcs = new;
186	}
187	debug_print_probes(entry);
188	return old;
189	}
190
191	/*
192	* Get tracepoint if the tracepoint is present in the tracepoint hash table.
193	* Must be called with tracepoints_mutex held.
194	* Returns NULL if not present.
195	*/
196	static struct tracepoint_entry get_tracepoint(const char name)
197	{
198	struct hlist_head *head;
199	struct hlist_node *node;
200	struct tracepoint_entry *e;
201	u32 hash = jhash(name, strlen(name), 0);
202
203	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
204	hlist_for_each_entry(e, node, head, hlist) {
205	if (!strcmp(name, e->name))
206	return e;
207	}
208	return NULL;
209	}
210
211	/*
212	* Add the tracepoint to the tracepoint hash table. Must be called with
213	* tracepoints_mutex held.
214	*/
215	static struct tracepoint_entry add_tracepoint(const char name)
216	{
217	struct hlist_head *head;
218	struct hlist_node *node;
219	struct tracepoint_entry *e;
220	size_t name_len = strlen(name) + 1;
221	u32 hash = jhash(name, name_len-1, 0);
222
223	head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
224	hlist_for_each_entry(e, node, head, hlist) {
225	if (!strcmp(name, e->name)) {
226	printk(KERN_NOTICE
227	"tracepoint %s busy\n", name);
228	return ERR_PTR(-EEXIST); /* Already there */
229	}
230	}
231	/*
232	* Using kmalloc here to allocate a variable length element. Could
233	* cause some memory fragmentation if overused.
234	*/
235	e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
236	if (!e)
237	return ERR_PTR(-ENOMEM);
238	memcpy(&e->name[0], name, name_len);
239	e->funcs = NULL;
240	e->refcount = 0;
241	hlist_add_head(&e->hlist, head);
242	return e;
243	}
244
245	/*
246	* Remove the tracepoint from the tracepoint hash table. Must be called with
247	* mutex_lock held.
248	*/
249	static inline void remove_tracepoint(struct tracepoint_entry *e)
250	{
251	hlist_del(&e->hlist);
252	kfree(e);
253	}
254
255	/*
256	* Sets the probe callback corresponding to one tracepoint.
257	*/
258	static void set_tracepoint(struct tracepoint_entry **entry,
259	struct tracepoint *elem, int active)
260	{
261	WARN_ON(strcmp((*entry)->name, elem->name) != 0);
262
263	/*
264	* rcu_assign_pointer has a smp_wmb() which makes sure that the new
265	* probe callbacks array is consistent before setting a pointer to it.
266	* This array is referenced by __DO_TRACE from
267	* include/linux/tracepoints.h. A matching smp_read_barrier_depends()
268	* is used.
269	*/
270	rcu_assign_pointer(elem->funcs, (*entry)->funcs);
271	elem->state__imv = active;
272	}
273
274	/*
275	* Disable a tracepoint and its probe callback.
276	* Note: only waiting an RCU period after setting elem->call to the empty
277	* function insures that the original callback is not used anymore. This insured
278	* by preempt_disable around the call site.
279	*/
280	static void disable_tracepoint(struct tracepoint *elem)
281	{
282	elem->state__imv = 0;
283	rcu_assign_pointer(elem->funcs, NULL);
284	}
285
286	/**
287	* tracepoint_update_probe_range - Update a probe range
288	* @begin: beginning of the range
289	* @end: end of the range
290	*
291	* Updates the probe callback corresponding to a range of tracepoints.
292	*/
293	void tracepoint_update_probe_range(struct tracepoint *begin,
294	struct tracepoint *end)
295	{
296	struct tracepoint *iter;
297	struct tracepoint_entry *mark_entry;
298
299	mutex_lock(&tracepoints_mutex);
300	for (iter = begin; iter < end; iter++) {
301	mark_entry = get_tracepoint(iter->name);
302	if (mark_entry) {
303	set_tracepoint(&mark_entry, iter,
304	!!mark_entry->refcount);
305	} else {
306	disable_tracepoint(iter);
307	}
308	}
309	mutex_unlock(&tracepoints_mutex);
310	}
311
312	/*
313	* Update probes, removing the faulty probes.
314	*/
315	static void tracepoint_update_probes(void)
316	{
317	/* Core kernel tracepoints */
474d745f PMF	318	//ust// tracepoint_update_probe_range(__start___tracepoints,
474d745f PMF	319	//ust// __stop___tracepoints);
f99be407	320	/* tracepoints in modules. */
474d745f	321	lib_update_tracepoints();
f99be407 PMF	322	/* Update immediate values */
f99be407 PMF	323	core_imv_update();
474d745f	324	//ust// module_imv_update();
f99be407 PMF	325	}
	326
	327	static void tracepoint_add_probe(const char name, void *probe)
	328	{
	329	struct tracepoint_entry *entry;
	330	void *old;
	331
	332	entry = get_tracepoint(name);
	333	if (!entry) {
	334	entry = add_tracepoint(name);
	335	if (IS_ERR(entry))
	336	return entry;
	337	}
	338	old = tracepoint_entry_add_probe(entry, probe);
	339	if (IS_ERR(old) && !entry->refcount)
	340	remove_tracepoint(entry);
	341	return old;
	342	}
	343
	344	/**
	345	* tracepoint_probe_register - Connect a probe to a tracepoint
	346	* @name: tracepoint name
	347	* @probe: probe handler
	348	*
	349	* Returns 0 if ok, error value on error.
	350	* The probe address must at least be aligned on the architecture pointer size.
	351	*/
	352	int tracepoint_probe_register(const char name, void probe)
	353	{
	354	void *old;
	355
	356	mutex_lock(&tracepoints_mutex);
	357	old = tracepoint_add_probe(name, probe);
	358	mutex_unlock(&tracepoints_mutex);
	359	if (IS_ERR(old))
	360	return PTR_ERR(old);
	361
	362	tracepoint_update_probes(); /* may update entry */
	363	release_probes(old);
	364	return 0;
	365	}
474d745f	366	//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register);
f99be407 PMF	367
	368	static void tracepoint_remove_probe(const char name, void *probe)
	369	{
	370	struct tracepoint_entry *entry;
	371	void *old;
	372
	373	entry = get_tracepoint(name);
	374	if (!entry)
	375	return ERR_PTR(-ENOENT);
	376	old = tracepoint_entry_remove_probe(entry, probe);
	377	if (IS_ERR(old))
	378	return old;
	379	if (!entry->refcount)
	380	remove_tracepoint(entry);
	381	return old;
	382	}
	383
	384	/**
	385	* tracepoint_probe_unregister - Disconnect a probe from a tracepoint
	386	* @name: tracepoint name
	387	* @probe: probe function pointer
	388	*
	389	* We do not need to call a synchronize_sched to make sure the probes have
	390	* finished running before doing a module unload, because the module unload
	391	* itself uses stop_machine(), which insures that every preempt disabled section
	392	* have finished.
	393	*/
	394	int tracepoint_probe_unregister(const char name, void probe)
	395	{
	396	void *old;
	397
	398	mutex_lock(&tracepoints_mutex);
	399	old = tracepoint_remove_probe(name, probe);
	400	mutex_unlock(&tracepoints_mutex);
	401	if (IS_ERR(old))
	402	return PTR_ERR(old);
	403
	404	tracepoint_update_probes(); /* may update entry */
	405	release_probes(old);
	406	return 0;
	407	}
474d745f	408	//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
f99be407 PMF	409
	410	static LIST_HEAD(old_probes);
	411	static int need_update;
	412
	413	static void tracepoint_add_old_probes(void *old)
	414	{
	415	need_update = 1;
	416	if (old) {
	417	struct tp_probes *tp_probes = container_of(old,
	418	struct tp_probes, probes[0]);
	419	list_add(&tp_probes->u.list, &old_probes);
	420	}
	421	}
	422
	423	/**
	424	* tracepoint_probe_register_noupdate - register a probe but not connect
	425	* @name: tracepoint name
	426	* @probe: probe handler
	427	*
	428	* caller must call tracepoint_probe_update_all()
	429	*/
	430	int tracepoint_probe_register_noupdate(const char name, void probe)
	431	{
	432	void *old;
	433
	434	mutex_lock(&tracepoints_mutex);
	435	old = tracepoint_add_probe(name, probe);
	436	if (IS_ERR(old)) {
	437	mutex_unlock(&tracepoints_mutex);
	438	return PTR_ERR(old);
	439	}
	440	tracepoint_add_old_probes(old);
	441	mutex_unlock(&tracepoints_mutex);
	442	return 0;
	443	}
474d745f	444	//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate);
f99be407 PMF	445
	446	/**
	447	* tracepoint_probe_unregister_noupdate - remove a probe but not disconnect
	448	* @name: tracepoint name
	449	* @probe: probe function pointer
	450	*
	451	* caller must call tracepoint_probe_update_all()
	452	*/
	453	int tracepoint_probe_unregister_noupdate(const char name, void probe)
	454	{
	455	void *old;
	456
	457	mutex_lock(&tracepoints_mutex);
	458	old = tracepoint_remove_probe(name, probe);
	459	if (IS_ERR(old)) {
	460	mutex_unlock(&tracepoints_mutex);
	461	return PTR_ERR(old);
	462	}
	463	tracepoint_add_old_probes(old);
	464	mutex_unlock(&tracepoints_mutex);
	465	return 0;
	466	}
474d745f	467	//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate);
f99be407 PMF	468
	469	/**
	470	* tracepoint_probe_update_all - update tracepoints
	471	*/
	472	void tracepoint_probe_update_all(void)
	473	{
	474	LIST_HEAD(release_probes);
	475	struct tp_probes pos, next;
	476
	477	mutex_lock(&tracepoints_mutex);
	478	if (!need_update) {
	479	mutex_unlock(&tracepoints_mutex);
	480	return;
	481	}
	482	if (!list_empty(&old_probes))
	483	list_replace_init(&old_probes, &release_probes);
	484	need_update = 0;
	485	mutex_unlock(&tracepoints_mutex);
	486
	487	tracepoint_update_probes();
	488	list_for_each_entry_safe(pos, next, &release_probes, u.list) {
	489	list_del(&pos->u.list);
474d745f PMF	490	//ust// call_rcu_sched(&pos->u.rcu, rcu_free_old_probes);
	491	synchronize_rcu();
	492	kfree(pos);
f99be407 PMF	493	}
f99be407 PMF	494	}
474d745f	495	//ust// EXPORT_SYMBOL_GPL(tracepoint_probe_update_all);
f99be407 PMF	496
	497	/**
	498	* tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
	499	* @tracepoint: current tracepoints (in), next tracepoint (out)
	500	* @begin: beginning of the range
	501	* @end: end of the range
	502	*
	503	* Returns whether a next tracepoint has been found (1) or not (0).
	504	* Will return the first tracepoint in the range if the input tracepoint is
	505	* NULL.
	506	*/
	507	int tracepoint_get_iter_range(struct tracepoint **tracepoint,
	508	struct tracepoint begin, struct tracepoint end)
	509	{
	510	if (!*tracepoint && begin != end) {
	511	*tracepoint = begin;
	512	return 1;
	513	}
	514	if (tracepoint >= begin && tracepoint < end)
	515	return 1;
	516	return 0;
	517	}
474d745f	518	//ust// EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
f99be407 PMF	519
	520	static void tracepoint_get_iter(struct tracepoint_iter *iter)
	521	{
	522	int found = 0;
	523
474d745f PMF	524	//ust// /* Core kernel tracepoints */
	525	//ust// if (!iter->module) {
	526	//ust// found = tracepoint_get_iter_range(&iter->tracepoint,
	527	//ust// __start___tracepoints, __stop___tracepoints);
	528	//ust// if (found)
	529	//ust// goto end;
	530	//ust// }
	531	/* tracepoints in libs. */
	532	found = lib_get_iter_tracepoints(iter);
f99be407 PMF	533	end:
	534	if (!found)
	535	tracepoint_iter_reset(iter);
	536	}
	537
	538	void tracepoint_iter_start(struct tracepoint_iter *iter)
	539	{
	540	tracepoint_get_iter(iter);
	541	}
474d745f	542	//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_start);
f99be407 PMF	543
	544	void tracepoint_iter_next(struct tracepoint_iter *iter)
	545	{
	546	iter->tracepoint++;
	547	/*
	548	* iter->tracepoint may be invalid because we blindly incremented it.
	549	* Make sure it is valid by marshalling on the tracepoints, getting the
	550	* tracepoints from following modules if necessary.
	551	*/
	552	tracepoint_get_iter(iter);
	553	}
474d745f	554	//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_next);
f99be407 PMF	555
	556	void tracepoint_iter_stop(struct tracepoint_iter *iter)
	557	{
	558	}
474d745f	559	//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
f99be407 PMF	560
	561	void tracepoint_iter_reset(struct tracepoint_iter *iter)
	562	{
474d745f	563	//ust// iter->module = NULL;
f99be407 PMF	564	iter->tracepoint = NULL;
f99be407 PMF	565	}
474d745f PMF	566	//ust// EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
	567
	568	//ust// #ifdef CONFIG_MODULES
	569
	570	//ust// int tracepoint_module_notify(struct notifier_block *self,
	571	//ust// unsigned long val, void *data)
	572	//ust// {
	573	//ust// struct module *mod = data;
	574	//ust//
	575	//ust// switch (val) {
	576	//ust// case MODULE_STATE_COMING:
	577	//ust// tracepoint_update_probe_range(mod->tracepoints,
	578	//ust// mod->tracepoints + mod->num_tracepoints);
	579	//ust// break;
	580	//ust// case MODULE_STATE_GOING:
	581	//ust// tracepoint_update_probe_range(mod->tracepoints,
	582	//ust// mod->tracepoints + mod->num_tracepoints);
	583	//ust// break;
	584	//ust// }
	585	//ust// return 0;
	586	//ust// }
	587
	588	//ust// struct notifier_block tracepoint_module_nb = {
	589	//ust// .notifier_call = tracepoint_module_notify,
	590	//ust// .priority = 0,
	591	//ust// };
	592
	593	//ust// static int init_tracepoints(void)
	594	//ust// {
	595	//ust// return register_module_notifier(&tracepoint_module_nb);
	596	//ust// }
	597	//ust// __initcall(init_tracepoints);
	598
	599	//ust// #endif /* CONFIG_MODULES */
f99be407	600
474d745f PMF	601	/*
	602	* Returns 0 if current not found.
	603	* Returns 1 if current found.
	604	*/
	605	int lib_get_iter_tracepoints(struct tracepoint_iter *iter)
f99be407	606	{
474d745f PMF	607	struct tracepoint_lib *iter_lib;
474d745f PMF	608	int found = 0;
f99be407	609
474d745f PMF	610	//ust// mutex_lock(&module_mutex);
	611	list_for_each_entry(iter_lib, &libs, list) {
	612	if (iter_lib < iter->lib)
	613	continue;
	614	else if (iter_lib > iter->lib)
	615	iter->tracepoint = NULL;
	616	found = marker_get_iter_range(&iter->tracepoint,
	617	iter_lib->tracepoints_start,
	618	iter_lib->tracepoints_start + iter_lib->tracepoints_count);
	619	if (found) {
	620	iter->lib = iter_lib;
	621	break;
	622	}
f99be407	623	}
474d745f PMF	624	//ust// mutex_unlock(&module_mutex);
474d745f PMF	625	return found;
f99be407 PMF	626	}
f99be407 PMF	627
474d745f PMF	628	void lib_update_tracepoints(void)
	629	{
	630	struct tracepoint_lib *lib;
	631
	632	//ust// mutex_lock(&module_mutex);
	633	list_for_each_entry(lib, &libs, list)
	634	tracepoint_update_probe_range(lib->tracepoints_start,
	635	lib->tracepoints_start + lib->tracepoints_count);
	636	//ust// mutex_unlock(&module_mutex);
	637	}
	638
	639	static void (new_tracepoint_cb)(struct tracepoint ) = NULL;
	640
	641	void tracepoint_set_new_tracepoint_cb(void (cb)(struct tracepoint ))
	642	{
	643	new_tracepoint_cb = cb;
	644	}
f99be407	645
474d745f	646	static void new_tracepoints(struct tracepoint start, struct tracepoint end)
f99be407	647	{
474d745f PMF	648	if(new_tracepoint_cb) {
	649	struct tracepoint *t;
	650	for(t=start; t < end; t++) {
	651	new_tracepoint_cb(t);
	652	}
	653	}
f99be407	654	}
f99be407	655
474d745f PMF	656	int tracepoint_register_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
	657	{
	658	struct tracepoint_lib *pl;
	659
	660	pl = (struct tracepoint_lib *) malloc(sizeof(struct tracepoint_lib));
	661
	662	pl->tracepoints_start = tracepoints_start;
	663	pl->tracepoints_count = tracepoints_count;
	664
	665	/* FIXME: maybe protect this with its own mutex? */
	666	mutex_lock(&tracepoints_mutex);
	667	list_add(&pl->list, &libs);
	668	mutex_unlock(&tracepoints_mutex);
	669
	670	new_tracepoints(tracepoints_start, tracepoints_start + tracepoints_count);
	671
	672	/* FIXME: update just the loaded lib */
	673	lib_update_tracepoints();
	674
	675	DBG("just registered a tracepoints section from %p and having %d tracepoints", tracepoints_start, tracepoints_count);
	676
	677	return 0;
	678	}
	679
	680	int tracepoint_unregister_lib(struct tracepoint *tracepoints_start, int tracepoints_count)
	681	{
	682	/*FIXME: implement; but before implementing, tracepoint_register_lib must
	683	have appropriate locking. */
	684
	685	return 0;
	686	}