[deliverable/linux.git] / samples / markers / probe-example.c

/* probe-example.c
 *
 * Connects two functions to marker call sites.
 *
 * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
 *
 * This file is released under the GPLv2.
 * See the file COPYING for more details.
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/marker.h>
#include <asm/atomic.h>

struct probe_data {
	const char *name;
	const char *format;
	marker_probe_func *probe_func;
};

void probe_subsystem_event(void *probe_data, void *call_data,
	const char *format, va_list *args)
{
	/* Declare args */
	unsigned int value;
	const char *mystr;

	/* Assign args */
	value = va_arg(*args, typeof(value));
	mystr = va_arg(*args, typeof(mystr));

	/* Call printk */
	printk(KERN_INFO "Value %u, string %s\n", value, mystr);

	/* or count, check rights, serialize data in a buffer */
}

atomic_t eventb_count = ATOMIC_INIT(0);

void probe_subsystem_eventb(void *probe_data, void *call_data,
	const char *format, va_list *args)
{
	/* Increment counter */
	atomic_inc(&eventb_count);
}

static struct probe_data probe_array[] =
{
	{	.name = "subsystem_event",
		.format = "integer %d string %s",
		.probe_func = probe_subsystem_event },
	{	.name = "subsystem_eventb",
		.format = MARK_NOARGS,
		.probe_func = probe_subsystem_eventb },
};

static int __init probe_init(void)
{
	int result;
	int i;

	for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
		result = marker_probe_register(probe_array[i].name,
				probe_array[i].format,
				probe_array[i].probe_func, &probe_array[i]);
		if (result)
			printk(KERN_INFO "Unable to register probe %s\n",
				probe_array[i].name);
	}
	return 0;
}

static void __exit probe_fini(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(probe_array); i++)
		marker_probe_unregister(probe_array[i].name,
			probe_array[i].probe_func, &probe_array[i]);
	printk(KERN_INFO "Number of event b : %u\n",
			atomic_read(&eventb_count));
	marker_synchronize_unregister();
}

module_init(probe_init);
module_exit(probe_fini);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("SUBSYSTEM Probe");
Commit	Line	Data
31155bc0 MD	1	/* probe-example.c
	2	*
	3	* Connects two functions to marker call sites.
	4	*
	5	* (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
	6	*
	7	* This file is released under the GPLv2.
	8	* See the file COPYING for more details.
	9	*/
	10
	11	#include <linux/sched.h>
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/marker.h>
	15	#include <asm/atomic.h>
	16
	17	struct probe_data {
	18	const char *name;
	19	const char *format;
	20	marker_probe_func *probe_func;
	21	};
	22
fb40bd78 MD	23	void probe_subsystem_event(void probe_data, void call_data,
fb40bd78 MD	24	const char format, va_list args)
31155bc0	25	{
31155bc0 MD	26	/* Declare args */
	27	unsigned int value;
	28	const char *mystr;
	29
	30	/* Assign args */
fb40bd78 MD	31	value = va_arg(*args, typeof(value));
fb40bd78 MD	32	mystr = va_arg(*args, typeof(mystr));
31155bc0 MD	33
31155bc0 MD	34	/* Call printk */
fb40bd78	35	printk(KERN_INFO "Value %u, string %s\n", value, mystr);
31155bc0 MD	36
31155bc0 MD	37	/* or count, check rights, serialize data in a buffer */
31155bc0 MD	38	}
	39
	40	atomic_t eventb_count = ATOMIC_INIT(0);
	41
fb40bd78 MD	42	void probe_subsystem_eventb(void probe_data, void call_data,
fb40bd78 MD	43	const char format, va_list args)
31155bc0 MD	44	{
	45	/* Increment counter */
	46	atomic_inc(&eventb_count);
	47	}
	48
	49	static struct probe_data probe_array[] =
	50	{
	51	{ .name = "subsystem_event",
cc9f2f8f	52	.format = "integer %d string %s",
31155bc0 MD	53	.probe_func = probe_subsystem_event },
	54	{ .name = "subsystem_eventb",
	55	.format = MARK_NOARGS,
	56	.probe_func = probe_subsystem_eventb },
	57	};
	58
	59	static int __init probe_init(void)
	60	{
	61	int result;
	62	int i;
	63
	64	for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
	65	result = marker_probe_register(probe_array[i].name,
	66	probe_array[i].format,
	67	probe_array[i].probe_func, &probe_array[i]);
	68	if (result)
	69	printk(KERN_INFO "Unable to register probe %s\n",
	70	probe_array[i].name);
31155bc0 MD	71	}
	72	return 0;
	73	}
	74
	75	static void __exit probe_fini(void)
	76	{
	77	int i;
	78
	79	for (i = 0; i < ARRAY_SIZE(probe_array); i++)
fb40bd78 MD	80	marker_probe_unregister(probe_array[i].name,
fb40bd78 MD	81	probe_array[i].probe_func, &probe_array[i]);
31155bc0 MD	82	printk(KERN_INFO "Number of event b : %u\n",
31155bc0 MD	83	atomic_read(&eventb_count));
531d2975	84	marker_synchronize_unregister();
31155bc0 MD	85	}
	86
	87	module_init(probe_init);
	88	module_exit(probe_fini);
	89
	90	MODULE_LICENSE("GPL");
	91	MODULE_AUTHOR("Mathieu Desnoyers");
	92	MODULE_DESCRIPTION("SUBSYSTEM Probe");