[lttng-modules.git] / ltt-events.c

/*
 * ltt-events.c
 *
 * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Holds LTTng per-session event registry.
 */

#include <linux/module.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/uuid.h>
#include "wrapper/vmalloc.h"	/* for wrapper_vmalloc_sync_all() */
#include "ltt-events.h"
#include "ltt-tracer.h"

static LIST_HEAD(sessions);
static LIST_HEAD(ltt_transport_list);
static DEFINE_MUTEX(sessions_mutex);
static struct kmem_cache *event_cache;

static
int _ltt_event_metadata_statedump(struct ltt_session *session,
				  struct ltt_channel *chan,
				  struct ltt_event *event);
static
int _ltt_session_metadata_statedump(struct ltt_session *session);


static
void synchronize_trace(void)
{
	synchronize_sched();
#ifdef CONFIG_PREEMPT_RT
	synchronize_rcu();
#endif
}

struct ltt_session *ltt_session_create(void)
{
	struct ltt_session *session;

	mutex_lock(&sessions_mutex);
	session = kzalloc(sizeof(struct ltt_session), GFP_KERNEL);
	if (!session)
		return NULL;
	INIT_LIST_HEAD(&session->chan);
	INIT_LIST_HEAD(&session->events);
	uuid_le_gen(&session->uuid);
	list_add(&session->list, &sessions);
	mutex_unlock(&sessions_mutex);
	return session;
}

void ltt_session_destroy(struct ltt_session *session)
{
	struct ltt_channel *chan, *tmpchan;
	struct ltt_event *event, *tmpevent;
	int ret;

	mutex_lock(&sessions_mutex);
	ACCESS_ONCE(session->active) = 0;
	list_for_each_entry(event, &session->events, list) {
		ret = _ltt_event_unregister(event);
		WARN_ON(ret);
	}
	synchronize_trace();	/* Wait for in-flight events to complete */
	list_for_each_entry_safe(event, tmpevent, &session->events, list)
		_ltt_event_destroy(event);
	list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
		_ltt_channel_destroy(chan);
	list_del(&session->list);
	mutex_unlock(&sessions_mutex);
	kfree(session);
}

int ltt_session_start(struct ltt_session *session)
{
	int ret = 0;
	struct ltt_channel *chan;

	mutex_lock(&sessions_mutex);
	if (session->active) {
		ret = -EBUSY;
		goto end;
	}

	/*
	 * Snapshot the number of events per channel to know the type of header
	 * we need to use.
	 */
	list_for_each_entry(chan, &session->chan, list) {
		if (chan->header_type)
			continue;		/* don't change it if session stop/restart */
		if (chan->free_event_id < 31)
			chan->header_type = 1;	/* compact */
		else
			chan->header_type = 2;	/* large */
	}

	ACCESS_ONCE(session->active) = 1;
	synchronize_trace();	/* Wait for in-flight events to complete */
	ret = _ltt_session_metadata_statedump(session);
	if (ret) {
		ACCESS_ONCE(session->active) = 0;
		synchronize_trace();	/* Wait for in-flight events to complete */
	}
end:
	mutex_unlock(&sessions_mutex);
	return ret;
}

int ltt_session_stop(struct ltt_session *session)
{
	int ret = 0;

	mutex_lock(&sessions_mutex);
	if (!session->active) {
		ret = -EBUSY;
		goto end;
	}
	ACCESS_ONCE(session->active) = 0;
	synchronize_trace();	/* Wait for in-flight events to complete */
end:
	mutex_unlock(&sessions_mutex);
	return ret;
}

static struct ltt_transport *ltt_transport_find(const char *name)
{
	struct ltt_transport *transport;

	list_for_each_entry(transport, &ltt_transport_list, node) {
		if (!strcmp(transport->name, name))
			return transport;
	}
	return NULL;
}

struct ltt_channel *ltt_channel_create(struct ltt_session *session,
				       const char *transport_name,
				       void *buf_addr,
				       size_t subbuf_size, size_t num_subbuf,
				       unsigned int switch_timer_interval,
				       unsigned int read_timer_interval)
{
	struct ltt_channel *chan;
	struct ltt_transport *transport;

	mutex_lock(&sessions_mutex);
	if (session->active) {
		printk(KERN_WARNING "LTTng refusing to add channel to active session\n");
		goto active;	/* Refuse to add channel to active session */
	}
	transport = ltt_transport_find(transport_name);
	if (!transport) {
		printk(KERN_WARNING "LTTng transport %s not found\n",
		       transport_name);
		goto notransport;
	}
	chan = kzalloc(sizeof(struct ltt_channel), GFP_KERNEL);
	if (!chan)
		goto nomem;
	chan->session = session;
	init_waitqueue_head(&chan->notify_wait);
	chan->chan = transport->ops.channel_create("[lttng]", session, buf_addr,
			subbuf_size, num_subbuf, switch_timer_interval,
			read_timer_interval);
	if (!chan->chan)
		goto create_error;
	chan->id = session->free_chan_id++;
	chan->ops = &transport->ops;
	list_add(&chan->list, &session->chan);
	mutex_unlock(&sessions_mutex);
	return chan;

create_error:
	kfree(chan);
nomem:
notransport:
active:
	mutex_unlock(&sessions_mutex);
	return NULL;
}

/*
 * Only used internally at session destruction.
 */
void _ltt_channel_destroy(struct ltt_channel *chan)
{
	chan->ops->channel_destroy(chan->chan);
	list_del(&chan->list);
	kfree(chan);
}

/*
 * Supports event creation while tracing session is active.
 */
struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name,
				   enum instrum_type itype,
				   const struct lttng_event_desc *event_desc,
				   void *filter)
{
	struct ltt_event *event;
	int ret;

	mutex_lock(&sessions_mutex);
	if (chan->free_event_id == -1UL)
		goto full;
	/*
	 * This is O(n^2) (for each event, the loop is called at event
	 * creation). Might require a hash if we have lots of events.
	 */
	list_for_each_entry(event, &chan->session->events, list)
		if (!strcmp(event->desc->name, name))
			goto exist;
	event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
	if (!event)
		goto cache_error;
	event->chan = chan;
	event->desc = event_desc;
	event->filter = filter;
	event->id = chan->free_event_id++;
	event->itype = itype;
	/* Populate ltt_event structure before tracepoint registration. */
	smp_wmb();
	switch (itype) {
	case INSTRUM_TRACEPOINTS:
		ret = tracepoint_probe_register(name, event_desc->probe_callback,
						event);
		if (ret)
			goto register_error;
		break;
	default:
		WARN_ON_ONCE(1);
	}
	ret = _ltt_event_metadata_statedump(chan->session, chan, event);
	if (ret)
		goto statedump_error;
	list_add(&event->list, &chan->session->events);
	mutex_unlock(&sessions_mutex);
	return event;

statedump_error:
	WARN_ON_ONCE(tracepoint_probe_unregister(name, event_desc->probe_callback,
						 event));
register_error:
	kmem_cache_free(event_cache, event);
cache_error:
exist:
full:
	mutex_unlock(&sessions_mutex);
	return NULL;
}

/*
 * Only used internally at session destruction.
 */
int _ltt_event_unregister(struct ltt_event *event)
{
	int ret = -EINVAL;

	switch (event->itype) {
	case INSTRUM_TRACEPOINTS:
		ret = tracepoint_probe_unregister(event->desc->name,
						  event->desc->probe_callback,
						  event);
		if (ret)
			return ret;
		break;
	default:
		WARN_ON_ONCE(1);
	}
	return ret;
}

/*
 * Only used internally at session destruction.
 */
void _ltt_event_destroy(struct ltt_event *event)
{
	ltt_event_put(event->desc);
	list_del(&event->list);
	kmem_cache_free(event_cache, event);
}

int lttng_metadata_printf(struct ltt_session *session,
			  const char *fmt, ...)
{
	struct lib_ring_buffer_ctx ctx;
	struct ltt_channel *chan = session->metadata;
	char *str;
	int ret = 0, waitret;
	size_t len;
	va_list ap;

	WARN_ON_ONCE(!ACCESS_ONCE(session->active));

	va_start(ap, fmt);
	str = kvasprintf(GFP_KERNEL, fmt, ap);
	va_end(ap);
	if (!str)
		return -ENOMEM;

	len = strlen(str) + 1;
	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, len, sizeof(char), -1);
	/*
	 * We don't care about metadata buffer's records lost count, because we
	 * always retry here. Report error if we need to bail out after timeout
	 * or being interrupted.
	 */
	waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan),
		({
			ret = chan->ops->event_reserve(&ctx);
			ret != -ENOBUFS || !ret;
		}),
		msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
	if (!waitret || waitret == -ERESTARTSYS || ret) {
		printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n",
			waitret == -ERESTARTSYS ? "interrupted" :
				(ret == -ENOBUFS ? "timeout" : "I/O error"));
		printk("waitret %d retval %d\n", waitret, ret);
		if (waitret == -ERESTARTSYS)
			ret = waitret;
		goto end;
	}
	chan->ops->event_write(&ctx, str, len);
	chan->ops->event_commit(&ctx);
end:
	kfree(str);
	return ret;
}

static
int _ltt_fields_metadata_statedump(struct ltt_session *session,
				   struct ltt_event *event)
{
	const struct lttng_event_desc *desc = event->desc;
	int ret = 0;
	int i;

	for (i = 0; i < desc->nr_fields; i++) {
		const struct lttng_event_field *field = &desc->fields[i];

		switch (field->type.atype) {
		case atype_integer:
			ret = lttng_metadata_printf(session,
				"		integer { size = %u; align = %u; signed = %u;%s } %s;\n",
				field->type.u.basic.integer.size,
				field->type.u.basic.integer.alignment,
				field->type.u.basic.integer.signedness,
#ifdef __BIG_ENDIAN
				field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
#else
				field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
#endif
				field->name);
			break;
		case atype_enum:
			ret = lttng_metadata_printf(session,
				"		%s %s;\n",
				field->type.u.basic.enumeration.name,
				field->name);
			break;
		case atype_array:
		{
			const struct lttng_basic_type *elem_type;

			elem_type = &field->type.u.array.elem_type;
			ret = lttng_metadata_printf(session,
				"		integer { size = %u; align = %u; signed = %u;%s } %s[%u];\n",
				elem_type->u.basic.integer.size,
				elem_type->u.basic.integer.alignment,
				elem_type->u.basic.integer.signedness,
#ifdef __BIG_ENDIAN
				elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
#else
				elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
#endif
				field->name, field->type.u.array.length);
			break;
		}
		case atype_sequence:
		{
			const struct lttng_basic_type *elem_type;
			const struct lttng_basic_type *length_type;

			elem_type = &field->type.u.sequence.elem_type;
			length_type = &field->type.u.sequence.length_type;
			ret = lttng_metadata_printf(session,
				"		integer { size = %u; align = %u; signed = %u;%s } %s[ integer { size = %u; align = %u; signed = %u;%s } ];\n",
				elem_type->u.basic.integer.size,
				elem_type->u.basic.integer.alignment,
				elem_type->u.basic.integer.signedness,
#ifdef __BIG_ENDIAN
				elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
#else
				elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
#endif
				field->name,
					length_type->u.basic.integer.size,
					length_type->u.basic.integer.alignment,
					length_type->u.basic.integer.signedness,
#ifdef __BIG_ENDIAN
					length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
#else
					length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : ""
#endif
				);
			break;
		}

		case atype_string:
			ret = lttng_metadata_printf(session,
				"		string%s %s;\n",
				field->type.u.basic.string.encoding == lttng_encode_ASCII ?
					" { encoding = ASCII; }" : "",
				field->name);
			break;
		default:
			WARN_ON_ONCE(1);
			return -EINVAL;
		}
	}
	return ret;
}

static
int _ltt_event_metadata_statedump(struct ltt_session *session,
				  struct ltt_channel *chan,
				  struct ltt_event *event)
{
	int ret = 0;

	if (event->metadata_dumped || !ACCESS_ONCE(session->active))
		return 0;
	if (chan == session->metadata)
		return 0;

	ret = lttng_metadata_printf(session,
		"event {\n"
		"	name = %s;\n"
		"	id = %u;\n"
		"	stream_id = %u;\n"
		"	event.fields := struct {\n",
		event->desc->name,
		event->id,
		event->chan->id);
	if (ret)
		goto end;

	ret = _ltt_fields_metadata_statedump(session, event);
	if (ret)
		goto end;

	/*
	 * LTTng space reservation can only reserve multiples of the
	 * byte size.
	 */
	ret = lttng_metadata_printf(session,
		"	} aligned(%u);\n"
		"};\n\n", ltt_get_header_alignment());
	if (ret)
		goto end;


	event->metadata_dumped = 1;
end:
	return ret;

}

static
int _ltt_channel_metadata_statedump(struct ltt_session *session,
				    struct ltt_channel *chan)
{
	int ret = 0;

	if (chan->metadata_dumped || !ACCESS_ONCE(session->active))
		return 0;
	if (chan == session->metadata)
		return 0;

	WARN_ON_ONCE(!chan->header_type);
	ret = lttng_metadata_printf(session,
		"stream {\n"
		"	id = %u;\n"
		"	event.header := %s;\n",
		"};\n\n",
		chan->id,
		chan->header_type == 1 ? "struct event_header_compact" :
			"struct event_header_large");
	if (ret)
		goto end;

	chan->metadata_dumped = 1;
end:
	return ret;
}

/*
 * Output metadata into this session's metadata buffers.
 */
static
int _ltt_session_metadata_statedump(struct ltt_session *session)
{
	char uuid_s[37];
	struct ltt_channel *chan;
	struct ltt_event *event;
	int ret = 0;

	if (!ACCESS_ONCE(session->active))
		return 0;
	if (session->metadata_dumped)
		goto skip_session;
	if (!session->metadata) {
		printk(KERN_WARNING "LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
		return -EPERM;
	}

	snprintf(uuid_s, sizeof(uuid_s),
		"%x%x%x%x-%x%x-%x%x-%x%x-%x%x%x%x%x%x",
		uuid_s[0], uuid_s[1], uuid_s[2], uuid_s[3],
		uuid_s[4], uuid_s[5], uuid_s[6], uuid_s[7],
		uuid_s[8], uuid_s[9], uuid_s[10], uuid_s[11],
		uuid_s[12], uuid_s[13], uuid_s[14], uuid_s[15]);

	ret = lttng_metadata_printf(session,
		"typealias integer {size = 8; align = %u; signed = false; } := uint8_t;\n"
		"typealias integer {size = 32; align = %u; signed = false; } := uint32_t;\n"
		"typealias integer {size = 64; align = %u; signed = false; } := uint64_t;\n"
		"\n"
		"trace {\n"
		"	major = %u;\n"
		"	minor = %u;\n"
		"	uuid = %s;\n"
		"	byte_order = %s;\n"
		"	packet.header := struct {\n"
		"		uint32_t magic;\n"
		"		uint8_t  trace_uuid[16];\n"
		"		uint32_t stream_id;\n"
		"		uint64_t timestamp_begin;\n"
		"		uint64_t timestamp_end;\n"
		"		uint32_t content_size;\n"
		"		uint32_t packet_size;\n"
		"		uint32_t events_lost;\n"
		"	};\n",
		"};\n\n",
		ltt_alignof(uint8_t) * CHAR_BIT,
		ltt_alignof(uint32_t) * CHAR_BIT,
		ltt_alignof(uint64_t) * CHAR_BIT,
		CTF_VERSION_MAJOR,
		CTF_VERSION_MINOR,
		uuid_s,
#ifdef __BIG_ENDIAN
		"be"
#else
		"le"
#endif
		);
	if (ret)
		goto end;

skip_session:
	list_for_each_entry(chan, &session->chan, list) {
		ret = _ltt_channel_metadata_statedump(session, chan);
		if (ret)
			goto end;
	}

	list_for_each_entry(event, &session->events, list) {
		ret = _ltt_event_metadata_statedump(session, chan, event);
		if (ret)
			goto end;
	}
	session->metadata_dumped = 1;
end:
	return ret;
}

/**
 * ltt_transport_register - LTT transport registration
 * @transport: transport structure
 *
 * Registers a transport which can be used as output to extract the data out of
 * LTTng. The module calling this registration function must ensure that no
 * trap-inducing code will be executed by the transport functions. E.g.
 * vmalloc_sync_all() must be called between a vmalloc and the moment the memory
 * is made visible to the transport function. This registration acts as a
 * vmalloc_sync_all. Therefore, only if the module allocates virtual memory
 * after its registration must it synchronize the TLBs.
 */
void ltt_transport_register(struct ltt_transport *transport)
{
	/*
	 * Make sure no page fault can be triggered by the module about to be
	 * registered. We deal with this here so we don't have to call
	 * vmalloc_sync_all() in each module's init.
	 */
	wrapper_vmalloc_sync_all();

	mutex_lock(&sessions_mutex);
	list_add_tail(&transport->node, &ltt_transport_list);
	mutex_unlock(&sessions_mutex);
}
EXPORT_SYMBOL_GPL(ltt_transport_register);

/**
 * ltt_transport_unregister - LTT transport unregistration
 * @transport: transport structure
 */
void ltt_transport_unregister(struct ltt_transport *transport)
{
	mutex_lock(&sessions_mutex);
	list_del(&transport->node);
	mutex_unlock(&sessions_mutex);
}
EXPORT_SYMBOL_GPL(ltt_transport_unregister);

static int __init ltt_events_init(void)
{
	int ret;

	event_cache = KMEM_CACHE(ltt_event, 0);
	if (!event_cache)
		return -ENOMEM;
	ret = ltt_debugfs_abi_init();
	if (ret)
		goto error_abi;
	return 0;
error_abi:
	kmem_cache_destroy(event_cache);
	return ret;
}

module_init(ltt_events_init);

static void __exit ltt_events_exit(void)
{
	struct ltt_session *session, *tmpsession;

	ltt_debugfs_abi_exit();
	list_for_each_entry_safe(session, tmpsession, &sessions, list)
		ltt_session_destroy(session);
	kmem_cache_destroy(event_cache);
}

module_exit(ltt_events_exit);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
MODULE_DESCRIPTION("LTTng Events");
Commit	Line	Data
4e3c1b9b MD	1	/*
	2	* ltt-events.c
	3	*
	4	* Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* Holds LTTng per-session event registry.
	7	*/
	8
	9	#include <linux/module.h>
c0e31d2e MD	10	#include <linux/list.h>
	11	#include <linux/mutex.h>
	12	#include <linux/sched.h>
11b5a3c2	13	#include <linux/slab.h>
c099397a	14	#include <linux/jiffies.h>
d793d5e1	15	#include <linux/uuid.h>
b13f3ebe	16	#include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
4e3c1b9b	17	#include "ltt-events.h"
c099397a	18	#include "ltt-tracer.h"
4e3c1b9b MD	19
4e3c1b9b MD	20	static LIST_HEAD(sessions);
c0e31d2e	21	static LIST_HEAD(ltt_transport_list);
4e3c1b9b MD	22	static DEFINE_MUTEX(sessions_mutex);
	23	static struct kmem_cache *event_cache;
	24
c099397a MD	25	static
	26	int _ltt_event_metadata_statedump(struct ltt_session *session,
	27	struct ltt_channel *chan,
	28	struct ltt_event *event);
	29	static
	30	int _ltt_session_metadata_statedump(struct ltt_session *session);
	31
	32
	33	static
	34	void synchronize_trace(void)
abcca994 MD	35	{
	36	synchronize_sched();
	37	#ifdef CONFIG_PREEMPT_RT
	38	synchronize_rcu();
	39	#endif
	40	}
	41
baf20995	42	struct ltt_session *ltt_session_create(void)
4e3c1b9b MD	43	{
	44	struct ltt_session *session;
	45
	46	mutex_lock(&sessions_mutex);
f3d01b96	47	session = kzalloc(sizeof(struct ltt_session), GFP_KERNEL);
4e3c1b9b MD	48	if (!session)
4e3c1b9b MD	49	return NULL;
4e3c1b9b	50	INIT_LIST_HEAD(&session->chan);
f3d01b96	51	INIT_LIST_HEAD(&session->events);
d793d5e1	52	uuid_le_gen(&session->uuid);
4e3c1b9b MD	53	list_add(&session->list, &sessions);
	54	mutex_unlock(&sessions_mutex);
	55	return session;
4e3c1b9b MD	56	}
4e3c1b9b MD	57
11b5a3c2	58	void ltt_session_destroy(struct ltt_session *session)
4e3c1b9b MD	59	{
	60	struct ltt_channel chan, tmpchan;
	61	struct ltt_event event, tmpevent;
dda6a249	62	int ret;
4e3c1b9b MD	63
4e3c1b9b MD	64	mutex_lock(&sessions_mutex);
52fc2e1f	65	ACCESS_ONCE(session->active) = 0;
dda6a249 MD	66	list_for_each_entry(event, &session->events, list) {
	67	ret = _ltt_event_unregister(event);
	68	WARN_ON(ret);
	69	}
abcca994	70	synchronize_trace(); /* Wait for in-flight events to complete */
4e3c1b9b MD	71	list_for_each_entry_safe(event, tmpevent, &session->events, list)
	72	_ltt_event_destroy(event);
	73	list_for_each_entry_safe(chan, tmpchan, &session->chan, list)
	74	_ltt_channel_destroy(chan);
	75	list_del(&session->list);
	76	mutex_unlock(&sessions_mutex);
	77	kfree(session);
	78	}
	79
c0e31d2e MD	80	int ltt_session_start(struct ltt_session *session)
	81	{
	82	int ret = 0;
c099397a	83	struct ltt_channel *chan;
c0e31d2e MD	84
	85	mutex_lock(&sessions_mutex);
	86	if (session->active) {
	87	ret = -EBUSY;
	88	goto end;
	89	}
c099397a MD	90
	91	/*
	92	* Snapshot the number of events per channel to know the type of header
	93	* we need to use.
	94	*/
	95	list_for_each_entry(chan, &session->chan, list) {
	96	if (chan->header_type)
	97	continue; /* don't change it if session stop/restart */
	98	if (chan->free_event_id < 31)
	99	chan->header_type = 1; /* compact */
	100	else
	101	chan->header_type = 2; /* large */
	102	}
	103
52fc2e1f	104	ACCESS_ONCE(session->active) = 1;
c0e31d2e	105	synchronize_trace(); /* Wait for in-flight events to complete */
c099397a MD	106	ret = _ltt_session_metadata_statedump(session);
	107	if (ret) {
	108	ACCESS_ONCE(session->active) = 0;
	109	synchronize_trace(); /* Wait for in-flight events to complete */
	110	}
c0e31d2e MD	111	end:
c0e31d2e MD	112	mutex_unlock(&sessions_mutex);
11b5a3c2	113	return ret;
c0e31d2e MD	114	}
	115
	116	int ltt_session_stop(struct ltt_session *session)
	117	{
	118	int ret = 0;
	119
	120	mutex_lock(&sessions_mutex);
	121	if (!session->active) {
	122	ret = -EBUSY;
	123	goto end;
	124	}
52fc2e1f	125	ACCESS_ONCE(session->active) = 0;
c0e31d2e MD	126	synchronize_trace(); /* Wait for in-flight events to complete */
	127	end:
	128	mutex_unlock(&sessions_mutex);
11b5a3c2	129	return ret;
c0e31d2e MD	130	}
c0e31d2e MD	131
c535175e	132	static struct ltt_transport ltt_transport_find(const char name)
f3d01b96 MD	133	{
	134	struct ltt_transport *transport;
	135
	136	list_for_each_entry(transport, &ltt_transport_list, node) {
	137	if (!strcmp(transport->name, name))
	138	return transport;
	139	}
	140	return NULL;
	141	}
	142
baf20995	143	struct ltt_channel ltt_channel_create(struct ltt_session session,
5dbbdb43 MD	144	const char *transport_name,
5dbbdb43 MD	145	void *buf_addr,
4e3c1b9b MD	146	size_t subbuf_size, size_t num_subbuf,
	147	unsigned int switch_timer_interval,
	148	unsigned int read_timer_interval)
	149	{
	150	struct ltt_channel *chan;
f3d01b96	151	struct ltt_transport *transport;
4e3c1b9b MD	152
4e3c1b9b MD	153	mutex_lock(&sessions_mutex);
f3d01b96 MD	154	if (session->active) {
f3d01b96 MD	155	printk(KERN_WARNING "LTTng refusing to add channel to active session\n");
e5382b6d	156	goto active; /* Refuse to add channel to active session */
c0e31d2e	157	}
f3d01b96 MD	158	transport = ltt_transport_find(transport_name);
	159	if (!transport) {
	160	printk(KERN_WARNING "LTTng transport %s not found\n",
	161	transport_name);
c0e31d2e	162	goto notransport;
f3d01b96	163	}
f3d01b96	164	chan = kzalloc(sizeof(struct ltt_channel), GFP_KERNEL);
4e3c1b9b	165	if (!chan)
c0e31d2e	166	goto nomem;
4e3c1b9b	167	chan->session = session;
653fe716	168	init_waitqueue_head(&chan->notify_wait);
11b5a3c2 MD	169	chan->chan = transport->ops.channel_create("[lttng]", session, buf_addr,
	170	subbuf_size, num_subbuf, switch_timer_interval,
	171	read_timer_interval);
f3d01b96 MD	172	if (!chan->chan)
f3d01b96 MD	173	goto create_error;
c099397a	174	chan->id = session->free_chan_id++;
11b5a3c2	175	chan->ops = &transport->ops;
4e3c1b9b MD	176	list_add(&chan->list, &session->chan);
	177	mutex_unlock(&sessions_mutex);
	178	return chan;
	179
f3d01b96 MD	180	create_error:
f3d01b96 MD	181	kfree(chan);
c0e31d2e MD	182	nomem:
c0e31d2e MD	183	notransport:
e5382b6d	184	active:
4e3c1b9b MD	185	mutex_unlock(&sessions_mutex);
	186	return NULL;
	187	}
	188
	189	/*
	190	* Only used internally at session destruction.
	191	*/
11b5a3c2	192	void _ltt_channel_destroy(struct ltt_channel *chan)
4e3c1b9b	193	{
11b5a3c2	194	chan->ops->channel_destroy(chan->chan);
4e3c1b9b MD	195	list_del(&chan->list);
	196	kfree(chan);
	197	}
	198
e5382b6d MD	199	/*
	200	* Supports event creation while tracing session is active.
	201	*/
4e3c1b9b	202	struct ltt_event ltt_event_create(struct ltt_channel chan, char *name,
baf20995	203	enum instrum_type itype,
85a9ca7f MD	204	const struct lttng_event_desc *event_desc,
85a9ca7f MD	205	void *filter)
4e3c1b9b MD	206	{
4e3c1b9b MD	207	struct ltt_event *event;
3d084699	208	int ret;
4e3c1b9b MD	209
4e3c1b9b MD	210	mutex_lock(&sessions_mutex);
e5382b6d MD	211	if (chan->free_event_id == -1UL)
e5382b6d MD	212	goto full;
4e3c1b9b	213	/*
dda6a249 MD	214	* This is O(n^2) (for each event, the loop is called at event
dda6a249 MD	215	* creation). Might require a hash if we have lots of events.
4e3c1b9b MD	216	*/
4e3c1b9b MD	217	list_for_each_entry(event, &chan->session->events, list)
85a9ca7f	218	if (!strcmp(event->desc->name, name))
4e3c1b9b	219	goto exist;
11b5a3c2	220	event = kmem_cache_zalloc(event_cache, GFP_KERNEL);
4e3c1b9b MD	221	if (!event)
4e3c1b9b MD	222	goto cache_error;
4e3c1b9b	223	event->chan = chan;
85a9ca7f	224	event->desc = event_desc;
4e3c1b9b	225	event->filter = filter;
e5382b6d	226	event->id = chan->free_event_id++;
baf20995	227	event->itype = itype;
e5382b6d MD	228	/* Populate ltt_event structure before tracepoint registration. */
e5382b6d MD	229	smp_wmb();
baf20995 MD	230	switch (itype) {
baf20995 MD	231	case INSTRUM_TRACEPOINTS:
85a9ca7f MD	232	ret = tracepoint_probe_register(name, event_desc->probe_callback,
85a9ca7f MD	233	event);
11b5a3c2 MD	234	if (ret)
11b5a3c2 MD	235	goto register_error;
baf20995 MD	236	break;
	237	default:
	238	WARN_ON_ONCE(1);
	239	}
c099397a MD	240	ret = _ltt_event_metadata_statedump(chan->session, chan, event);
	241	if (ret)
	242	goto statedump_error;
dda6a249	243	list_add(&event->list, &chan->session->events);
11b5a3c2	244	mutex_unlock(&sessions_mutex);
4e3c1b9b MD	245	return event;
4e3c1b9b MD	246
c099397a MD	247	statedump_error:
	248	WARN_ON_ONCE(tracepoint_probe_unregister(name, event_desc->probe_callback,
	249	event));
11b5a3c2	250	register_error:
11b5a3c2	251	kmem_cache_free(event_cache, event);
4e3c1b9b MD	252	cache_error:
4e3c1b9b MD	253	exist:
e5382b6d	254	full:
4e3c1b9b MD	255	mutex_unlock(&sessions_mutex);
	256	return NULL;
	257	}
	258
	259	/*
	260	* Only used internally at session destruction.
	261	*/
dda6a249	262	int _ltt_event_unregister(struct ltt_event *event)
4e3c1b9b	263	{
11b5a3c2 MD	264	int ret = -EINVAL;
11b5a3c2 MD	265
baf20995 MD	266	switch (event->itype) {
baf20995 MD	267	case INSTRUM_TRACEPOINTS:
85a9ca7f MD	268	ret = tracepoint_probe_unregister(event->desc->name,
85a9ca7f MD	269	event->desc->probe_callback,
11b5a3c2 MD	270	event);
	271	if (ret)
	272	return ret;
baf20995 MD	273	break;
	274	default:
	275	WARN_ON_ONCE(1);
	276	}
dda6a249 MD	277	return ret;
	278	}
	279
	280	/*
	281	* Only used internally at session destruction.
	282	*/
	283	void _ltt_event_destroy(struct ltt_event *event)
	284	{
85a9ca7f	285	ltt_event_put(event->desc);
dda6a249	286	list_del(&event->list);
11b5a3c2	287	kmem_cache_free(event_cache, event);
4e3c1b9b MD	288	}
4e3c1b9b MD	289
c099397a MD	290	int lttng_metadata_printf(struct ltt_session *session,
	291	const char *fmt, ...)
	292	{
	293	struct lib_ring_buffer_ctx ctx;
	294	struct ltt_channel *chan = session->metadata;
	295	char *str;
	296	int ret = 0, waitret;
	297	size_t len;
	298	va_list ap;
	299
	300	WARN_ON_ONCE(!ACCESS_ONCE(session->active));
	301
	302	va_start(ap, fmt);
	303	str = kvasprintf(GFP_KERNEL, fmt, ap);
	304	va_end(ap);
	305	if (!str)
	306	return -ENOMEM;
	307
	308	len = strlen(str) + 1;
	309	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, len, sizeof(char), -1);
	310	/*
	311	* We don't care about metadata buffer's records lost count, because we
	312	* always retry here. Report error if we need to bail out after timeout
	313	* or being interrupted.
	314	*/
	315	waitret = wait_event_interruptible_timeout(*chan->ops->get_reader_wait_queue(chan),
	316	({
	317	ret = chan->ops->event_reserve(&ctx);
	318	ret != -ENOBUFS \|\| !ret;
	319	}),
	320	msecs_to_jiffies(LTTNG_METADATA_TIMEOUT_MSEC));
d793d5e1	321	if (!waitret \|\| waitret == -ERESTARTSYS \|\| ret) {
c099397a MD	322	printk(KERN_WARNING "LTTng: Failure to write metadata to buffers (%s)\n",
	323	waitret == -ERESTARTSYS ? "interrupted" :
	324	(ret == -ENOBUFS ? "timeout" : "I/O error"));
d793d5e1	325	printk("waitret %d retval %d\n", waitret, ret);
c099397a MD	326	if (waitret == -ERESTARTSYS)
	327	ret = waitret;
	328	goto end;
	329	}
	330	chan->ops->event_write(&ctx, str, len);
	331	chan->ops->event_commit(&ctx);
	332	end:
	333	kfree(str);
	334	return ret;
	335	}
	336
	337	static
	338	int _ltt_fields_metadata_statedump(struct ltt_session *session,
	339	struct ltt_event *event)
	340	{
	341	const struct lttng_event_desc *desc = event->desc;
	342	int ret = 0;
	343	int i;
	344
	345	for (i = 0; i < desc->nr_fields; i++) {
	346	const struct lttng_event_field *field = &desc->fields[i];
	347
	348	switch (field->type.atype) {
	349	case atype_integer:
	350	ret = lttng_metadata_printf(session,
	351	" integer { size = %u; align = %u; signed = %u;%s } %s;\n",
	352	field->type.u.basic.integer.size,
	353	field->type.u.basic.integer.alignment,
	354	field->type.u.basic.integer.signedness,
	355	#ifdef __BIG_ENDIAN
	356	field->type.u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
	357	#else
	358	field->type.u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
	359	#endif
	360	field->name);
	361	break;
	362	case atype_enum:
	363	ret = lttng_metadata_printf(session,
	364	" %s %s;\n",
	365	field->type.u.basic.enumeration.name,
	366	field->name);
	367	break;
	368	case atype_array:
8fa75f34 MD	369	{
	370	const struct lttng_basic_type *elem_type;
	371
	372	elem_type = &field->type.u.array.elem_type;
	373	ret = lttng_metadata_printf(session,
	374	" integer { size = %u; align = %u; signed = %u;%s } %s[%u];\n",
	375	elem_type->u.basic.integer.size,
	376	elem_type->u.basic.integer.alignment,
	377	elem_type->u.basic.integer.signedness,
	378	#ifdef __BIG_ENDIAN
	379	elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
	380	#else
	381	elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
	382	#endif
	383	field->name, field->type.u.array.length);
c099397a	384	break;
8fa75f34	385	}
c099397a	386	case atype_sequence:
8fa75f34 MD	387	{
	388	const struct lttng_basic_type *elem_type;
	389	const struct lttng_basic_type *length_type;
	390
	391	elem_type = &field->type.u.sequence.elem_type;
	392	length_type = &field->type.u.sequence.length_type;
	393	ret = lttng_metadata_printf(session,
	394	" integer { size = %u; align = %u; signed = %u;%s } %s[ integer { size = %u; align = %u; signed = %u;%s } ];\n",
	395	elem_type->u.basic.integer.size,
	396	elem_type->u.basic.integer.alignment,
	397	elem_type->u.basic.integer.signedness,
	398	#ifdef __BIG_ENDIAN
	399	elem_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
	400	#else
	401	elem_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : "",
	402	#endif
	403	field->name,
	404	length_type->u.basic.integer.size,
	405	length_type->u.basic.integer.alignment,
	406	length_type->u.basic.integer.signedness,
	407	#ifdef __BIG_ENDIAN
	408	length_type->u.basic.integer.reverse_byte_order ? " byte_order = le;" : "",
	409	#else
	410	length_type->u.basic.integer.reverse_byte_order ? " byte_order = be;" : ""
	411	#endif
	412	);
c099397a	413	break;
8fa75f34	414	}
c099397a MD	415
	416	case atype_string:
	417	ret = lttng_metadata_printf(session,
	418	" string%s %s;\n",
	419	field->type.u.basic.string.encoding == lttng_encode_ASCII ?
	420	" { encoding = ASCII; }" : "",
	421	field->name);
	422	break;
	423	default:
	424	WARN_ON_ONCE(1);
	425	return -EINVAL;
	426	}
	427	}
	428	return ret;
	429	}
	430
	431	static
	432	int _ltt_event_metadata_statedump(struct ltt_session *session,
	433	struct ltt_channel *chan,
	434	struct ltt_event *event)
	435	{
	436	int ret = 0;
	437
	438	if (event->metadata_dumped \|\| !ACCESS_ONCE(session->active))
	439	return 0;
	440	if (chan == session->metadata)
	441	return 0;
	442
	443	ret = lttng_metadata_printf(session,
	444	"event {\n"
	445	" name = %s;\n"
	446	" id = %u;\n"
	447	" stream_id = %u;\n"
	448	" event.fields := struct {\n",
	449	event->desc->name,
	450	event->id,
	451	event->chan->id);
	452	if (ret)
	453	goto end;
	454
	455	ret = _ltt_fields_metadata_statedump(session, event);
	456	if (ret)
	457	goto end;
	458
	459	/*
	460	* LTTng space reservation can only reserve multiples of the
	461	* byte size.
	462	*/
	463	ret = lttng_metadata_printf(session,
	464	" } aligned(%u);\n"
d793d5e1	465	"};\n\n", ltt_get_header_alignment());
c099397a MD	466	if (ret)
	467	goto end;
	468
	469
	470
	471
	472	event->metadata_dumped = 1;
	473	end:
	474	return ret;
	475
	476	}
	477
	478	static
	479	int _ltt_channel_metadata_statedump(struct ltt_session *session,
	480	struct ltt_channel *chan)
	481	{
	482	int ret = 0;
	483
	484	if (chan->metadata_dumped \|\| !ACCESS_ONCE(session->active))
	485	return 0;
	486	if (chan == session->metadata)
	487	return 0;
	488
	489	WARN_ON_ONCE(!chan->header_type);
	490	ret = lttng_metadata_printf(session,
	491	"stream {\n"
	492	" id = %u;\n"
	493	" event.header := %s;\n",
d793d5e1	494	"};\n\n",
c099397a MD	495	chan->id,
	496	chan->header_type == 1 ? "struct event_header_compact" :
	497	"struct event_header_large");
	498	if (ret)
	499	goto end;
	500
	501	chan->metadata_dumped = 1;
	502	end:
	503	return ret;
	504	}
	505
	506	/*
	507	* Output metadata into this session's metadata buffers.
	508	*/
	509	static
	510	int _ltt_session_metadata_statedump(struct ltt_session *session)
	511	{
d793d5e1	512	char uuid_s[37];
c099397a MD	513	struct ltt_channel *chan;
	514	struct ltt_event *event;
	515	int ret = 0;
	516
	517	if (!ACCESS_ONCE(session->active))
	518	return 0;
	519	if (session->metadata_dumped)
	520	goto skip_session;
f40270ad	521	if (!session->metadata) {
cd4bd11f	522	printk(KERN_WARNING "LTTng: attempt to start tracing, but metadata channel is not found. Operation abort.\n");
f40270ad MD	523	return -EPERM;
f40270ad MD	524	}
c099397a	525
d793d5e1 MD	526	snprintf(uuid_s, sizeof(uuid_s),
	527	"%x%x%x%x-%x%x-%x%x-%x%x-%x%x%x%x%x%x",
	528	uuid_s[0], uuid_s[1], uuid_s[2], uuid_s[3],
	529	uuid_s[4], uuid_s[5], uuid_s[6], uuid_s[7],
	530	uuid_s[8], uuid_s[9], uuid_s[10], uuid_s[11],
	531	uuid_s[12], uuid_s[13], uuid_s[14], uuid_s[15]);
	532
	533	ret = lttng_metadata_printf(session,
	534	"typealias integer {size = 8; align = %u; signed = false; } := uint8_t;\n"
	535	"typealias integer {size = 32; align = %u; signed = false; } := uint32_t;\n"
	536	"typealias integer {size = 64; align = %u; signed = false; } := uint64_t;\n"
	537	"\n"
	538	"trace {\n"
	539	" major = %u;\n"
	540	" minor = %u;\n"
	541	" uuid = %s;\n"
	542	" byte_order = %s;\n"
	543	" packet.header := struct {\n"
	544	" uint32_t magic;\n"
	545	" uint8_t trace_uuid[16];\n"
	546	" uint32_t stream_id;\n"
	547	" uint64_t timestamp_begin;\n"
	548	" uint64_t timestamp_end;\n"
	549	" uint32_t content_size;\n"
	550	" uint32_t packet_size;\n"
	551	" uint32_t events_lost;\n"
	552	" };\n",
	553	"};\n\n",
	554	ltt_alignof(uint8_t) * CHAR_BIT,
	555	ltt_alignof(uint32_t) * CHAR_BIT,
	556	ltt_alignof(uint64_t) * CHAR_BIT,
	557	CTF_VERSION_MAJOR,
	558	CTF_VERSION_MINOR,
	559	uuid_s,
	560	#ifdef __BIG_ENDIAN
	561	"be"
	562	#else
	563	"le"
	564	#endif
	565	);
	566	if (ret)
	567	goto end;
	568
c099397a MD	569	skip_session:
	570	list_for_each_entry(chan, &session->chan, list) {
	571	ret = _ltt_channel_metadata_statedump(session, chan);
	572	if (ret)
	573	goto end;
	574	}
	575
	576	list_for_each_entry(event, &session->events, list) {
	577	ret = _ltt_event_metadata_statedump(session, chan, event);
	578	if (ret)
	579	goto end;
	580	}
	581	session->metadata_dumped = 1;
	582	end:
	583	return ret;
	584	}
	585
c0e31d2e MD	586	/**
	587	* ltt_transport_register - LTT transport registration
	588	* @transport: transport structure
	589	*
	590	* Registers a transport which can be used as output to extract the data out of
	591	* LTTng. The module calling this registration function must ensure that no
	592	* trap-inducing code will be executed by the transport functions. E.g.
	593	* vmalloc_sync_all() must be called between a vmalloc and the moment the memory
	594	* is made visible to the transport function. This registration acts as a
	595	* vmalloc_sync_all. Therefore, only if the module allocates virtual memory
	596	* after its registration must it synchronize the TLBs.
	597	*/
	598	void ltt_transport_register(struct ltt_transport *transport)
	599	{
	600	/*
	601	* Make sure no page fault can be triggered by the module about to be
	602	* registered. We deal with this here so we don't have to call
	603	* vmalloc_sync_all() in each module's init.
	604	*/
6d2a620c	605	wrapper_vmalloc_sync_all();
c0e31d2e MD	606
	607	mutex_lock(&sessions_mutex);
	608	list_add_tail(&transport->node, &ltt_transport_list);
	609	mutex_unlock(&sessions_mutex);
	610	}
	611	EXPORT_SYMBOL_GPL(ltt_transport_register);
	612
	613	/**
	614	* ltt_transport_unregister - LTT transport unregistration
	615	* @transport: transport structure
	616	*/
	617	void ltt_transport_unregister(struct ltt_transport *transport)
	618	{
	619	mutex_lock(&sessions_mutex);
	620	list_del(&transport->node);
	621	mutex_unlock(&sessions_mutex);
	622	}
	623	EXPORT_SYMBOL_GPL(ltt_transport_unregister);
	624
4e3c1b9b MD	625	static int __init ltt_events_init(void)
4e3c1b9b MD	626	{
1c25284c MD	627	int ret;
1c25284c MD	628
11b5a3c2 MD	629	event_cache = KMEM_CACHE(ltt_event, 0);
11b5a3c2 MD	630	if (!event_cache)
4e3c1b9b	631	return -ENOMEM;
02119ee5 MD	632	ret = ltt_debugfs_abi_init();
	633	if (ret)
	634	goto error_abi;
4e3c1b9b	635	return 0;
02119ee5	636	error_abi:
1c25284c MD	637	kmem_cache_destroy(event_cache);
1c25284c MD	638	return ret;
4e3c1b9b MD	639	}
4e3c1b9b MD	640
11b5a3c2 MD	641	module_init(ltt_events_init);
11b5a3c2 MD	642
4e3c1b9b MD	643	static void __exit ltt_events_exit(void)
4e3c1b9b MD	644	{
92e94819 MD	645	struct ltt_session session, tmpsession;
92e94819 MD	646
1c25284c	647	ltt_debugfs_abi_exit();
92e94819 MD	648	list_for_each_entry_safe(session, tmpsession, &sessions, list)
92e94819 MD	649	ltt_session_destroy(session);
11b5a3c2	650	kmem_cache_destroy(event_cache);
4e3c1b9b	651	}
92e94819	652
11b5a3c2 MD	653	module_exit(ltt_events_exit);
11b5a3c2 MD	654
92e94819 MD	655	MODULE_LICENSE("GPL and additional rights");
	656	MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
	657	MODULE_DESCRIPTION("LTTng Events");