1 files changed, 278 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
new file mode 100644
index 000000000000..60a6a6d66dc0
--- /dev/null
+++ b/kernel/trace/trace_events_trigger.c
@@ -0,0 +1,278 @@
+/*
+ * trace_events_trigger - trace event triggers
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) 2013 Tom Zanussi <tom.zanussi@linux.intel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+#include "trace.h"
+
+static LIST_HEAD(trigger_commands);
+static DEFINE_MUTEX(trigger_cmd_mutex);
+
+/**
+ * event_triggers_call - Call triggers associated with a trace event
+ * @file: The ftrace_event_file associated with the event
+ *
+ * For each trigger associated with an event, invoke the trigger
+ * function registered with the associated trigger command.
+ *
+ * Called from tracepoint handlers (with rcu_read_lock_sched() held).
+ *
+ * Return: an enum event_trigger_type value containing a set bit for
+ * any trigger that should be deferred, ETT_NONE if nothing to defer.
+ */
+void event_triggers_call(struct ftrace_event_file *file)
+{
+	struct event_trigger_data *data;
+
+	if (list_empty(&file->triggers))
+		return;
+
+	list_for_each_entry_rcu(data, &file->triggers, list)
+		data->ops->func(data);
+}
+EXPORT_SYMBOL_GPL(event_triggers_call);
+
+static void *trigger_next(struct seq_file *m, void *t, loff_t *pos)
+{
+	struct ftrace_event_file *event_file = event_file_data(m->private);
+
+	return seq_list_next(t, &event_file->triggers, pos);
+}
+
+static void *trigger_start(struct seq_file *m, loff_t *pos)
+{
+	struct ftrace_event_file *event_file;
+
+	/* ->stop() is called even if ->start() fails */
+	mutex_lock(&event_mutex);
+	event_file = event_file_data(m->private);
+	if (unlikely(!event_file))
+		return ERR_PTR(-ENODEV);
+
+	return seq_list_start(&event_file->triggers, *pos);
+}
+
+static void trigger_stop(struct seq_file *m, void *t)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static int trigger_show(struct seq_file *m, void *v)
+{
+	struct event_trigger_data *data;
+
+	data = list_entry(v, struct event_trigger_data, list);
+	data->ops->print(m, data->ops, data);
+
+	return 0;
+}
+
+static const struct seq_operations event_triggers_seq_ops = {
+	.start = trigger_start,
+	.next = trigger_next,
+	.stop = trigger_stop,
+	.show = trigger_show,
+};
+
+static int event_trigger_regex_open(struct inode *inode, struct file *file)
+{
+	int ret = 0;
+
+	mutex_lock(&event_mutex);
+
+	if (unlikely(!event_file_data(file))) {
+		mutex_unlock(&event_mutex);
+		return -ENODEV;
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		ret = seq_open(file, &event_triggers_seq_ops);
+		if (!ret) {
+			struct seq_file *m = file->private_data;
+			m->private = file;
+		}
+	}
+
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int trigger_process_regex(struct ftrace_event_file *file, char *buff)
+{
+	char *command, *next = buff;
+	struct event_command *p;
+	int ret = -EINVAL;
+
+	command = strsep(&next, ": \t");
+	command = (command[0] != '!') ? command : command + 1;
+
+	mutex_lock(&trigger_cmd_mutex);
+	list_for_each_entry(p, &trigger_commands, list) {
+		if (strcmp(p->name, command) == 0) {
+			ret = p->func(p, file, buff, command, next);
+			goto out_unlock;
+		}
+	}
+ out_unlock:
+	mutex_unlock(&trigger_cmd_mutex);
+
+	return ret;
+}
+
+static ssize_t event_trigger_regex_write(struct file *file,
+					 const char __user *ubuf,
+					 size_t cnt, loff_t *ppos)
+{
+	struct ftrace_event_file *event_file;
+	ssize_t ret;
+	char *buf;
+
+	if (!cnt)
+		return 0;
+
+	if (cnt >= PAGE_SIZE)
+		return -EINVAL;
+
+	buf = (char *)__get_free_page(GFP_TEMPORARY);
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, ubuf, cnt)) {
+		free_page((unsigned long)buf);
+		return -EFAULT;
+	}
+	buf[cnt] = '\0';
+	strim(buf);
+
+	mutex_lock(&event_mutex);
+	event_file = event_file_data(file);
+	if (unlikely(!event_file)) {
+		mutex_unlock(&event_mutex);
+		free_page((unsigned long)buf);
+		return -ENODEV;
+	}
+	ret = trigger_process_regex(event_file, buf);
+	mutex_unlock(&event_mutex);
+
+	free_page((unsigned long)buf);
+	if (ret < 0)
+		goto out;
+
+	*ppos += cnt;
+	ret = cnt;
+ out:
+	return ret;
+}
+
+static int event_trigger_regex_release(struct inode *inode, struct file *file)
+{
+	mutex_lock(&event_mutex);
+
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+
+	mutex_unlock(&event_mutex);
+
+	return 0;
+}
+
+static ssize_t
+event_trigger_write(struct file *filp, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return event_trigger_regex_write(filp, ubuf, cnt, ppos);
+}
+
+static int
+event_trigger_open(struct inode *inode, struct file *filp)
+{
+	return event_trigger_regex_open(inode, filp);
+}
+
+static int
+event_trigger_release(struct inode *inode, struct file *file)
+{
+	return event_trigger_regex_release(inode, file);
+}
+
+const struct file_operations event_trigger_fops = {
+	.open = event_trigger_open,
+	.read = seq_read,
+	.write = event_trigger_write,
+	.llseek = ftrace_filter_lseek,
+	.release = event_trigger_release,
+};
+
+static int trace_event_trigger_enable_disable(struct ftrace_event_file *file,
+					      int trigger_enable)
+{
+	int ret = 0;
+
+	if (trigger_enable) {
+		if (atomic_inc_return(&file->tm_ref) > 1)
+			return ret;
+		set_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags);
+		ret = trace_event_enable_disable(file, 1, 1);
+	} else {
+		if (atomic_dec_return(&file->tm_ref) > 0)
+			return ret;
+		clear_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &file->flags);
+		ret = trace_event_enable_disable(file, 0, 1);
+	}
+
+	return ret;
+}
+
+/**
+ * clear_event_triggers - Clear all triggers associated with a trace array
+ * @tr: The trace array to clear
+ *
+ * For each trigger, the triggering event has its tm_ref decremented
+ * via trace_event_trigger_enable_disable(), and any associated event
+ * (in the case of enable/disable_event triggers) will have its sm_ref
+ * decremented via free()->trace_event_enable_disable().  That
+ * combination effectively reverses the soft-mode/trigger state added
+ * by trigger registration.
+ *
+ * Must be called with event_mutex held.
+ */
+void
+clear_event_triggers(struct trace_array *tr)
+{
+	struct ftrace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list) {
+		struct event_trigger_data *data;
+		list_for_each_entry_rcu(data, &file->triggers, list) {
+			trace_event_trigger_enable_disable(file, 0);
+			if (data->ops->free)
+				data->ops->free(data->ops, data);
+		}
+	}
+}
+
+__init int register_trigger_cmds(void)
+{
+	return 0;
+}