[lttng-modules.git] / lttng-context-prio.c

/*
 * lttng-context-prio.c
 *
 * LTTng priority context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <lttng-events.h>
#include <wrapper/ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <wrapper/kallsyms.h>
#include <lttng-tracer.h>

static
int (*wrapper_task_prio_sym)(struct task_struct *t);

int wrapper_task_prio_init(void)
{
	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
	if (!wrapper_task_prio_sym) {
		printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
		return -EINVAL;
	}
	return 0;
}

static
size_t prio_get_size(size_t offset)
{
	size_t size = 0;

	size += lib_ring_buffer_align(offset, lttng_alignof(int));
	size += sizeof(int);
	return size;
}

static
void prio_record(struct lttng_ctx_field *field,
		struct lib_ring_buffer_ctx *ctx,
		struct lttng_channel *chan)
{
	int prio;

	prio = wrapper_task_prio_sym(current);
	lib_ring_buffer_align_ctx(ctx, lttng_alignof(prio));
	chan->ops->event_write(ctx, &prio, sizeof(prio));
}

static
void prio_get_value(struct lttng_ctx_field *field,
		struct lttng_probe_ctx *lttng_probe_ctx,
		union lttng_ctx_value *value)
{
	value->s64 = wrapper_task_prio_sym(current);
}

int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
{
	struct lttng_ctx_field *field;
	int ret;

	if (!wrapper_task_prio_sym) {
		ret = wrapper_task_prio_init();
		if (ret)
			return ret;
	}

	field = lttng_append_context(ctx);
	if (!field)
		return -ENOMEM;
	if (lttng_find_context(*ctx, "prio")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "prio";
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.alignment = lttng_alignof(int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int);
	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	field->event_field.type.u.basic.integer.base = 10;
	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	field->get_size = prio_get_size;
	field->record = prio_record;
	field->get_value = prio_get_value;
	lttng_context_update(*ctx);
	wrapper_vmalloc_sync_all();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);
Commit	Line	Data
a8ad3613	1	/*
886d51a3	2	* lttng-context-prio.c
a8ad3613 MD	3	*
	4	* LTTng priority context.
	5	*
886d51a3 MD	6	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; only
	11	* version 2.1 of the License.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
a8ad3613 MD	21	*/
	22
	23	#include <linux/module.h>
	24	#include <linux/slab.h>
	25	#include <linux/sched.h>
241ae9a8 MD	26	#include <lttng-events.h>
	27	#include <wrapper/ringbuffer/frontend_types.h>
	28	#include <wrapper/vmalloc.h>
	29	#include <wrapper/kallsyms.h>
	30	#include <lttng-tracer.h>
a8ad3613	31
979133c5 MD	32	static
	33	int (wrapper_task_prio_sym)(struct task_struct t);
	34
	35	int wrapper_task_prio_init(void)
	36	{
c539a324	37	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
979133c5 MD	38	if (!wrapper_task_prio_sym) {
	39	printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
	40	return -EINVAL;
	41	}
	42	return 0;
	43	}
	44
a8ad3613 MD	45	static
	46	size_t prio_get_size(size_t offset)
	47	{
	48	size_t size = 0;
	49
a90917c3	50	size += lib_ring_buffer_align(offset, lttng_alignof(int));
a8ad3613 MD	51	size += sizeof(int);
	52	return size;
	53	}
	54
	55	static
	56	void prio_record(struct lttng_ctx_field *field,
	57	struct lib_ring_buffer_ctx *ctx,
a90917c3	58	struct lttng_channel *chan)
a8ad3613 MD	59	{
	60	int prio;
	61
8fefc8a2	62	prio = wrapper_task_prio_sym(current);
a90917c3	63	lib_ring_buffer_align_ctx(ctx, lttng_alignof(prio));
53f1f0ca	64	chan->ops->event_write(ctx, &prio, sizeof(prio));
a8ad3613 MD	65	}
a8ad3613 MD	66
f127e61e MD	67	static
f127e61e MD	68	void prio_get_value(struct lttng_ctx_field *field,
79150a49	69	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	70	union lttng_ctx_value *value)
	71	{
	72	value->s64 = wrapper_task_prio_sym(current);
	73	}
	74
a8ad3613 MD	75	int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
	76	{
	77	struct lttng_ctx_field *field;
	78	int ret;
	79
979133c5 MD	80	if (!wrapper_task_prio_sym) {
	81	ret = wrapper_task_prio_init();
	82	if (ret)
	83	return ret;
	84	}
	85
a8ad3613 MD	86	field = lttng_append_context(ctx);
a8ad3613 MD	87	if (!field)
09fec6b4	88	return -ENOMEM;
44252f0f MD	89	if (lttng_find_context(*ctx, "prio")) {
	90	lttng_remove_context_field(ctx, field);
	91	return -EEXIST;
	92	}
a8ad3613 MD	93	field->event_field.name = "prio";
	94	field->event_field.type.atype = atype_integer;
	95	field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
a90917c3	96	field->event_field.type.u.basic.integer.alignment = lttng_alignof(int) * CHAR_BIT;
06254b0f	97	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int);
a8ad3613 MD	98	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	99	field->event_field.type.u.basic.integer.base = 10;
	100	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	101	field->get_size = prio_get_size;
	102	field->record = prio_record;
f127e61e	103	field->get_value = prio_get_value;
a9dd15da	104	lttng_context_update(*ctx);
a8ad3613 MD	105	wrapper_vmalloc_sync_all();
	106	return 0;
	107	}
	108	EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);