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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-prio.c
 *
 * LTTng priority context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <lttng-events.h>
#include <wrapper/ringbuffer/frontend_types.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.integer.size = sizeof(int) * CHAR_BIT;
	field->event_field.type.u.integer.alignment = lttng_alignof(int) * CHAR_BIT;
	field->event_field.type.u.integer.signedness = lttng_is_signed_type(int);
	field->event_field.type.u.integer.reverse_byte_order = 0;
	field->event_field.type.u.integer.base = 10;
	field->event_field.type.u.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);
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
9f36eaed	2	*
886d51a3	3	* lttng-context-prio.c
a8ad3613 MD	4	*
	5	* LTTng priority context.
	6	*
886d51a3	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
a8ad3613 MD	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/slab.h>
	12	#include <linux/sched.h>
241ae9a8 MD	13	#include <lttng-events.h>
241ae9a8 MD	14	#include <wrapper/ringbuffer/frontend_types.h>
241ae9a8 MD	15	#include <wrapper/kallsyms.h>
241ae9a8 MD	16	#include <lttng-tracer.h>
a8ad3613	17
979133c5 MD	18	static
	19	int (wrapper_task_prio_sym)(struct task_struct t);
	20
	21	int wrapper_task_prio_init(void)
	22	{
c539a324	23	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
979133c5 MD	24	if (!wrapper_task_prio_sym) {
	25	printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
	26	return -EINVAL;
	27	}
	28	return 0;
	29	}
	30
a8ad3613 MD	31	static
	32	size_t prio_get_size(size_t offset)
	33	{
	34	size_t size = 0;
	35
a90917c3	36	size += lib_ring_buffer_align(offset, lttng_alignof(int));
a8ad3613 MD	37	size += sizeof(int);
	38	return size;
	39	}
	40
	41	static
	42	void prio_record(struct lttng_ctx_field *field,
	43	struct lib_ring_buffer_ctx *ctx,
a90917c3	44	struct lttng_channel *chan)
a8ad3613 MD	45	{
	46	int prio;
	47
8fefc8a2	48	prio = wrapper_task_prio_sym(current);
a90917c3	49	lib_ring_buffer_align_ctx(ctx, lttng_alignof(prio));
53f1f0ca	50	chan->ops->event_write(ctx, &prio, sizeof(prio));
a8ad3613 MD	51	}
a8ad3613 MD	52
f127e61e MD	53	static
f127e61e MD	54	void prio_get_value(struct lttng_ctx_field *field,
79150a49	55	struct lttng_probe_ctx *lttng_probe_ctx,
f127e61e MD	56	union lttng_ctx_value *value)
	57	{
	58	value->s64 = wrapper_task_prio_sym(current);
	59	}
	60
a8ad3613 MD	61	int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
	62	{
	63	struct lttng_ctx_field *field;
	64	int ret;
	65
979133c5 MD	66	if (!wrapper_task_prio_sym) {
	67	ret = wrapper_task_prio_init();
	68	if (ret)
	69	return ret;
	70	}
	71
a8ad3613 MD	72	field = lttng_append_context(ctx);
a8ad3613 MD	73	if (!field)
09fec6b4	74	return -ENOMEM;
44252f0f MD	75	if (lttng_find_context(*ctx, "prio")) {
	76	lttng_remove_context_field(ctx, field);
	77	return -EEXIST;
	78	}
a8ad3613 MD	79	field->event_field.name = "prio";
a8ad3613 MD	80	field->event_field.type.atype = atype_integer;
ceabb767 MD	81	field->event_field.type.u.integer.size = sizeof(int) * CHAR_BIT;
	82	field->event_field.type.u.integer.alignment = lttng_alignof(int) * CHAR_BIT;
	83	field->event_field.type.u.integer.signedness = lttng_is_signed_type(int);
	84	field->event_field.type.u.integer.reverse_byte_order = 0;
	85	field->event_field.type.u.integer.base = 10;
	86	field->event_field.type.u.integer.encoding = lttng_encode_none;
a8ad3613 MD	87	field->get_size = prio_get_size;
a8ad3613 MD	88	field->record = prio_record;
f127e61e	89	field->get_value = prio_get_value;
a9dd15da	90	lttng_context_update(*ctx);
a8ad3613 MD	91	return 0;
	92	}
	93	EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);