linux-imx

/*

 * Copyright (C) 2008-2014 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/sched/signal.h>

#include <linux/sched/task.h>

#include <linux/static_key.h>

​

extern tracepoint_ptr_t __start___tracepoints_ptrs[];

extern tracepoint_ptr_t __stop___tracepoints_ptrs[];

​

DEFINE_SRCU(tracepoint_srcu);

EXPORT_SYMBOL_GPL(tracepoint_srcu);

​

/* Set to 1 to enable tracepoint debug output */

static const int tracepoint_debug;

​

#ifdef CONFIG_MODULES

/*

 * Tracepoint module list mutex protects the local module list.

 */

static DEFINE_MUTEX(tracepoint_module_list_mutex);

​

/* Local list of struct tp_module */

static LIST_HEAD(tracepoint_module_list);

#endif /* CONFIG_MODULES */

​

/*

 * tracepoints_mutex protects the builtin and module tracepoints.

 * tracepoints_mutex nests inside tracepoint_module_list_mutex.

 */

static DEFINE_MUTEX(tracepoints_mutex);

​

static struct rcu_head *early_probes;

static bool ok_to_free_tracepoints;

​

/*

 * Note about RCU :

 * It is used to delay the free of multiple probes array until a quiescent

 * state is reached.

 */

struct tp_probes {

    struct rcu_head rcu;

    struct tracepoint_func probes[0];

};

​

static inline void *allocate_probes(int count)

{

    struct tp_probes *p  = kmalloc(count * sizeof(struct tracepoint_func)

            + sizeof(struct tp_probes), GFP_KERNEL);

    return p == NULL ? NULL : p->probes;

}

​

static void srcu_free_old_probes(struct rcu_head *head)

{

    kfree(container_of(head, struct tp_probes, rcu));

}

​

static void rcu_free_old_probes(struct rcu_head *head)

{

    call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);

}

​

static __init int release_early_probes(void)

{

    struct rcu_head *tmp;

​

    ok_to_free_tracepoints = true;

​

    while (early_probes) {