lttng: tracer control and core structures

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/lttng/ltt-endian.h

+#ifndef _LTT_ENDIAN_H
+#define _LTT_ENDIAN_H
+
+/*
+ * ltt-endian.h
+ *
+ * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#ifdef __KERNEL__
+# include <asm/byteorder.h>
+# ifdef __BIG_ENDIAN
+#  define __BYTE_ORDER __BIG_ENDIAN
+# elif defined(__LITTLE_ENDIAN)
+#  define __BYTE_ORDER __LITTLE_ENDIAN
+# else
+#  error "unknown endianness"
+# endif
+#ifndef __BIG_ENDIAN
+# define __BIG_ENDIAN 4321
+#endif
+#ifndef __LITTLE_ENDIAN
+# define __LITTLE_ENDIAN 1234
+#endif
+#else
+# include <endian.h>
+#endif
+
+#endif /* _LTT_ENDIAN_H */

drivers/staging/lttng/ltt-probes.c

+/*
+ * ltt-probes.c
+ *
+ * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Holds LTTng probes registry.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+
+#include "ltt-events.h"
+
+static LIST_HEAD(probe_list);
+static DEFINE_MUTEX(probe_mutex);
+
+static
+const struct lttng_event_desc *find_event(const char *name)
+{
+	struct lttng_probe_desc *probe_desc;
+	int i;
+
+	list_for_each_entry(probe_desc, &probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			if (!strcmp(probe_desc->event_desc[i]->name, name))
+				return probe_desc->event_desc[i];
+		}
+	}
+	return NULL;
+}
+
+int ltt_probe_register(struct lttng_probe_desc *desc)
+{
+	int ret = 0;
+	int i;
+
+	mutex_lock(&probe_mutex);
+	/*
+	 * TODO: This is O(N^2). Turn into a hash table when probe registration
+	 * overhead becomes an issue.
+	 */
+	for (i = 0; i < desc->nr_events; i++) {
+		if (find_event(desc->event_desc[i]->name)) {
+			ret = -EEXIST;
+			goto end;
+		}
+	}
+	list_add(&desc->head, &probe_list);
+end:
+	mutex_unlock(&probe_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ltt_probe_register);
+
+void ltt_probe_unregister(struct lttng_probe_desc *desc)
+{
+	mutex_lock(&probe_mutex);
+	list_del(&desc->head);
+	mutex_unlock(&probe_mutex);
+}
+EXPORT_SYMBOL_GPL(ltt_probe_unregister);
+
+const struct lttng_event_desc *ltt_event_get(const char *name)
+{
+	const struct lttng_event_desc *event;
+	int ret;
+
+	mutex_lock(&probe_mutex);
+	event = find_event(name);
+	mutex_unlock(&probe_mutex);
+	if (!event)
+		return NULL;
+	ret = try_module_get(event->owner);
+	WARN_ON_ONCE(!ret);
+	return event;
+}
+EXPORT_SYMBOL_GPL(ltt_event_get);
+
+void ltt_event_put(const struct lttng_event_desc *event)
+{
+	module_put(event->owner);
+}
+EXPORT_SYMBOL_GPL(ltt_event_put);
+
+static
+void *tp_list_start(struct seq_file *m, loff_t *pos)
+{
+	struct lttng_probe_desc *probe_desc;
+	int iter = 0, i;
+
+	mutex_lock(&probe_mutex);
+	list_for_each_entry(probe_desc, &probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			if (iter++ >= *pos)
+				return (void *) probe_desc->event_desc[i];
+		}
+	}
+	/* End of list */
+	return NULL;
+}
+
+static
+void *tp_list_next(struct seq_file *m, void *p, loff_t *ppos)
+{
+	struct lttng_probe_desc *probe_desc;
+	int iter = 0, i;
+
+	(*ppos)++;
+	list_for_each_entry(probe_desc, &probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			if (iter++ >= *ppos)
+				return (void *) probe_desc->event_desc[i];
+		}
+	}
+	/* End of list */
+	return NULL;
+}
+
+static
+void tp_list_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&probe_mutex);
+}
+
+static
+int tp_list_show(struct seq_file *m, void *p)
+{
+	const struct lttng_event_desc *probe_desc = p;
+
+	/*
+	 * Don't export lttng internal events (metadata).
+	 */
+	if (!strncmp(probe_desc->name, "lttng_", sizeof("lttng_") - 1))
+		return 0;
+	seq_printf(m,	"event { name = %s; };\n",
+		   probe_desc->name);
+	return 0;
+}
+
+static
+const struct seq_operations lttng_tracepoint_list_seq_ops = {
+	.start = tp_list_start,
+	.next = tp_list_next,
+	.stop = tp_list_stop,
+	.show = tp_list_show,
+};
+
+static
+int lttng_tracepoint_list_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &lttng_tracepoint_list_seq_ops);
+}
+
+const struct file_operations lttng_tracepoint_list_fops = {
+	.owner = THIS_MODULE,
+	.open = lttng_tracepoint_list_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};

drivers/staging/lttng/ltt-tracer-core.h

+#ifndef LTT_TRACER_CORE_H
+#define LTT_TRACER_CORE_H
+
+/*
+ * ltt-tracer-core.h
+ *
+ * Copyright (C) 2005-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This contains the core definitions for the Linux Trace Toolkit.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <linux/list.h>
+#include <linux/percpu.h>
+
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+/* Align data on its natural alignment */
+#define RING_BUFFER_ALIGN
+#endif
+
+#include "wrapper/ringbuffer/config.h"
+
+struct ltt_session;
+struct ltt_channel;
+struct ltt_event;
+
+#endif /* LTT_TRACER_CORE_H */

drivers/staging/lttng/ltt-tracer.h

+#ifndef _LTT_TRACER_H
+#define _LTT_TRACER_H
+
+/*
+ * ltt-tracer.h
+ *
+ * Copyright (C) 2005-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This contains the definitions for the Linux Trace Toolkit tracer.
+ *
+ * Dual LGPL v2.1/GPL v2 license.
+ */
+
+#include <stdarg.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include <linux/list.h>
+#include <linux/cache.h>
+#include <linux/timex.h>
+#include <linux/wait.h>
+#include <asm/atomic.h>
+#include <asm/local.h>
+
+#include "wrapper/trace-clock.h"
+#include "ltt-tracer-core.h"
+#include "ltt-events.h"
+
+#define LTTNG_VERSION 0
+#define LTTNG_PATCHLEVEL 9
+#define LTTNG_SUBLEVEL 1
+
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+
+/* Number of bytes to log with a read/write event */
+#define LTT_LOG_RW_SIZE			32L
+#define LTT_MAX_SMALL_SIZE		0xFFFFU
+
+#ifdef RING_BUFFER_ALIGN
+#define ltt_alignof(type)	__alignof__(type)
+#else
+#define ltt_alignof(type)	1
+#endif
+
+/* Tracer properties */
+#define CTF_MAGIC_NUMBER		0xC1FC1FC1
+#define TSDL_MAGIC_NUMBER		0x75D11D57
+
+/* CTF specification version followed */
+#define CTF_SPEC_MAJOR			1
+#define CTF_SPEC_MINOR			8
+
+/* Tracer major/minor versions */
+#define CTF_VERSION_MAJOR		0
+#define CTF_VERSION_MINOR		1
+
+/*
+ * Number of milliseconds to retry before failing metadata writes on buffer full
+ * condition. (10 seconds)
+ */
+#define LTTNG_METADATA_TIMEOUT_MSEC	10000
+
+#define LTT_RFLAG_EXTENDED		RING_BUFFER_RFLAG_END
+#define LTT_RFLAG_END			(LTT_RFLAG_EXTENDED << 1)
+
+#endif /* _LTT_TRACER_H */