1 files changed, 731 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
new file mode 100644
index 000000000000..210e71ff82db
--- /dev/null
+++ b/kernel/trace/trace_events.c
@@ -0,0 +1,731 @@
+/*
+ * event tracer
+ *
+ * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ *  - Added format output of fields of the trace point.
+ *    This was based off of work by Tom Zanussi <tzanussi@gmail.com>.
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+
+#include "trace_output.h"
+
+#define TRACE_SYSTEM "TRACE_SYSTEM"
+
+static DEFINE_MUTEX(event_mutex);
+
+#define events_for_each(event)						\
+	for (event = __start_ftrace_events;				\
+	     (unsigned long)event < (unsigned long)__stop_ftrace_events; \
+	     event++)
+
+void event_trace_printk(unsigned long ip, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	tracing_record_cmdline(current);
+	trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+	va_end(ap);
+}
+
+static void ftrace_clear_events(void)
+{
+	struct ftrace_event_call *call = (void *)__start_ftrace_events;
+
+
+	while ((unsigned long)call < (unsigned long)__stop_ftrace_events) {
+
+		if (call->enabled) {
+			call->enabled = 0;
+			call->unregfunc();
+		}
+		call++;
+	}
+}
+
+static void ftrace_event_enable_disable(struct ftrace_event_call *call,
+					int enable)
+{
+
+	switch (enable) {
+	case 0:
+		if (call->enabled) {
+			call->enabled = 0;
+			call->unregfunc();
+		}
+		if (call->raw_enabled) {
+			call->raw_enabled = 0;
+			call->raw_unreg();
+		}
+		break;
+	case 1:
+		if (!call->enabled &&
+		    (call->type & TRACE_EVENT_TYPE_PRINTF)) {
+			call->enabled = 1;
+			call->regfunc();
+		}
+		if (!call->raw_enabled &&
+		    (call->type & TRACE_EVENT_TYPE_RAW)) {
+			call->raw_enabled = 1;
+			call->raw_reg();
+		}
+		break;
+	}
+}
+
+static int ftrace_set_clr_event(char *buf, int set)
+{
+	struct ftrace_event_call *call = __start_ftrace_events;
+	char *event = NULL, *sub = NULL, *match;
+	int ret = -EINVAL;
+
+	/*
+	 * The buf format can be <subsystem>:<event-name>
+	 *  *:<event-name> means any event by that name.
+	 *  :<event-name> is the same.
+	 *
+	 *  <subsystem>:* means all events in that subsystem
+	 *  <subsystem>: means the same.
+	 *
+	 *  <name> (no ':') means all events in a subsystem with
+	 *  the name <name> or any event that matches <name>
+	 */
+
+	match = strsep(&buf, ":");
+	if (buf) {
+		sub = match;
+		event = buf;
+		match = NULL;
+
+		if (!strlen(sub) || strcmp(sub, "*") == 0)
+			sub = NULL;
+		if (!strlen(event) || strcmp(event, "*") == 0)
+			event = NULL;
+	}
+
+	mutex_lock(&event_mutex);
+	events_for_each(call) {
+
+		if (!call->name)
+			continue;
+
+		if (match &&
+		    strcmp(match, call->name) != 0 &&
+		    strcmp(match, call->system) != 0)
+			continue;
+
+		if (sub && strcmp(sub, call->system) != 0)
+			continue;
+
+		if (event && strcmp(event, call->name) != 0)
+			continue;
+
+		ftrace_event_enable_disable(call, set);
+
+		ret = 0;
+	}
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+/* 128 should be much more than enough */
+#define EVENT_BUF_SIZE		127
+
+static ssize_t
+ftrace_event_write(struct file *file, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	size_t read = 0;
+	int i, set = 1;
+	ssize_t ret;
+	char *buf;
+	char ch;
+
+	if (!cnt || cnt < 0)
+		return 0;
+
+	ret = get_user(ch, ubuf++);
+	if (ret)
+		return ret;
+	read++;
+	cnt--;
+
+	/* skip white space */
+	while (cnt && isspace(ch)) {
+		ret = get_user(ch, ubuf++);
+		if (ret)
+			return ret;
+		read++;
+		cnt--;
+	}
+
+	/* Only white space found? */
+	if (isspace(ch)) {
+		file->f_pos += read;
+		ret = read;
+		return ret;
+	}
+
+	buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (cnt > EVENT_BUF_SIZE)
+		cnt = EVENT_BUF_SIZE;
+
+	i = 0;
+	while (cnt && !isspace(ch)) {
+		if (!i && ch == '!')
+			set = 0;
+		else
+			buf[i++] = ch;
+
+		ret = get_user(ch, ubuf++);
+		if (ret)
+			goto out_free;
+		read++;
+		cnt--;
+	}
+	buf[i] = 0;
+
+	file->f_pos += read;
+
+	ret = ftrace_set_clr_event(buf, set);
+	if (ret)
+		goto out_free;
+
+	ret = read;
+
+ out_free:
+	kfree(buf);
+
+	return ret;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct ftrace_event_call *call = m->private;
+	struct ftrace_event_call *next = call;
+
+	(*pos)++;
+
+	if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
+		return NULL;
+
+	m->private = ++next;
+
+	return call;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	return t_next(m, NULL, pos);
+}
+
+static void *
+s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct ftrace_event_call *call = m->private;
+	struct ftrace_event_call *next;
+
+	(*pos)++;
+
+ retry:
+	if ((unsigned long)call >= (unsigned long)__stop_ftrace_events)
+		return NULL;
+
+	if (!call->enabled) {
+		call++;
+		goto retry;
+	}
+
+	next = call;
+	m->private = ++next;
+
+	return call;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	return s_next(m, NULL, pos);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	struct ftrace_event_call *call = v;
+
+	if (strcmp(call->system, TRACE_SYSTEM) != 0)
+		seq_printf(m, "%s:", call->system);
+	seq_printf(m, "%s\n", call->name);
+
+	return 0;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+}
+
+static int
+ftrace_event_seq_open(struct inode *inode, struct file *file)
+{
+	int ret;
+	const struct seq_operations *seq_ops;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    !(file->f_flags & O_APPEND))
+		ftrace_clear_events();
+
+	seq_ops = inode->i_private;
+	ret = seq_open(file, seq_ops);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+
+		m->private = __start_ftrace_events;
+	}
+	return ret;
+}
+
+static ssize_t
+event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	char *buf;
+
+	if (call->enabled || call->raw_enabled)
+		buf = "1\n";
+	else
+		buf = "0\n";
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		   loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	char buf[64];
+	unsigned long val;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	switch (val) {
+	case 0:
+	case 1:
+		mutex_lock(&event_mutex);
+		ftrace_event_enable_disable(call, val);
+		mutex_unlock(&event_mutex);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+event_type_read(struct file *filp, char __user *ubuf, size_t cnt,
+		loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	char buf[16];
+	int r = 0;
+
+	if (call->type & TRACE_EVENT_TYPE_PRINTF)
+		r += sprintf(buf, "printf\n");
+
+	if (call->type & TRACE_EVENT_TYPE_RAW)
+		r += sprintf(buf+r, "raw\n");
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+event_type_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		 loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	char buf[64];
+
+	/*
+	 * If there's only one type, we can't change it.
+	 * And currently we always have printf type, and we
+	 * may or may not have raw type.
+	 *
+	 * This is a redundant check, the file should be read
+	 * only if this is the case anyway.
+	 */
+
+	if (!call->raw_init)
+		return -EPERM;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	if (!strncmp(buf, "printf", 6) &&
+	    (!buf[6] || isspace(buf[6]))) {
+
+		call->type = TRACE_EVENT_TYPE_PRINTF;
+
+		/*
+		 * If raw enabled, the disable it and enable
+		 * printf type.
+		 */
+		if (call->raw_enabled) {
+			call->raw_enabled = 0;
+			call->raw_unreg();
+
+			call->enabled = 1;
+			call->regfunc();
+		}
+
+	} else if (!strncmp(buf, "raw", 3) &&
+	    (!buf[3] || isspace(buf[3]))) {
+
+		call->type = TRACE_EVENT_TYPE_RAW;
+
+		/*
+		 * If printf enabled, the disable it and enable
+		 * raw type.
+		 */
+		if (call->enabled) {
+			call->enabled = 0;
+			call->unregfunc();
+
+			call->raw_enabled = 1;
+			call->raw_reg();
+		}
+	} else
+		return -EINVAL;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+event_available_types_read(struct file *filp, char __user *ubuf, size_t cnt,
+			   loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	char buf[16];
+	int r = 0;
+
+	r += sprintf(buf, "printf\n");
+
+	if (call->raw_init)
+		r += sprintf(buf+r, "raw\n");
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+#undef FIELD
+#define FIELD(type, name) \
+	#type, #name, offsetof(typeof(field), name), sizeof(field.name)
+
+static int trace_write_header(struct trace_seq *s)
+{
+	struct trace_entry field;
+
+	/* struct trace_entry */
+	return trace_seq_printf(s,
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\tfield:%s %s;\toffset:%lu;\tsize:%lu;\n"
+				"\n",
+				FIELD(unsigned char, type),
+				FIELD(unsigned char, flags),
+				FIELD(unsigned char, preempt_count),
+				FIELD(int, pid),
+				FIELD(int, tgid));
+}
+static ssize_t
+event_format_read(struct file *filp, char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	struct ftrace_event_call *call = filp->private_data;
+	struct trace_seq *s;
+	char *buf;
+	int r;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	if (*ppos)
+		return 0;
+
+	/* If any of the first writes fail, so will the show_format. */
+
+	trace_seq_printf(s, "name: %s\n", call->name);
+	trace_seq_printf(s, "ID: %d\n", call->id);
+	trace_seq_printf(s, "format:\n");
+	trace_write_header(s);
+
+	r = call->show_format(s);
+	if (!r) {
+		/*
+		 * ug!  The format output is bigger than a PAGE!!
+		 */
+		buf = "FORMAT TOO BIG\n";
+		r = simple_read_from_buffer(ubuf, cnt, ppos,
+					      buf, strlen(buf));
+		goto out;
+	}
+
+	r = simple_read_from_buffer(ubuf, cnt, ppos,
+				    s->buffer, s->len);
+ out:
+	kfree(s);
+	return r;
+}
+
+static const struct seq_operations show_event_seq_ops = {
+	.start = t_start,
+	.next = t_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static const struct seq_operations show_set_event_seq_ops = {
+	.start = s_start,
+	.next = s_next,
+	.show = t_show,
+	.stop = t_stop,
+};
+
+static const struct file_operations ftrace_avail_fops = {
+	.open = ftrace_event_seq_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static const struct file_operations ftrace_set_event_fops = {
+	.open = ftrace_event_seq_open,
+	.read = seq_read,
+	.write = ftrace_event_write,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static const struct file_operations ftrace_enable_fops = {
+	.open = tracing_open_generic,
+	.read = event_enable_read,
+	.write = event_enable_write,
+};
+
+static const struct file_operations ftrace_type_fops = {
+	.open = tracing_open_generic,
+	.read = event_type_read,
+	.write = event_type_write,
+};
+
+static const struct file_operations ftrace_available_types_fops = {
+	.open = tracing_open_generic,
+	.read = event_available_types_read,
+};
+
+static const struct file_operations ftrace_event_format_fops = {
+	.open = tracing_open_generic,
+	.read = event_format_read,
+};
+
+static struct dentry *event_trace_events_dir(void)
+{
+	static struct dentry *d_tracer;
+	static struct dentry *d_events;
+
+	if (d_events)
+		return d_events;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return NULL;
+
+	d_events = debugfs_create_dir("events", d_tracer);
+	if (!d_events)
+		pr_warning("Could not create debugfs "
+			   "'events' directory\n");
+
+	return d_events;
+}
+
+struct event_subsystem {
+	struct list_head	list;
+	const char		*name;
+	struct dentry		*entry;
+};
+
+static LIST_HEAD(event_subsystems);
+
+static struct dentry *
+event_subsystem_dir(const char *name, struct dentry *d_events)
+{
+	struct event_subsystem *system;
+
+	/* First see if we did not already create this dir */
+	list_for_each_entry(system, &event_subsystems, list) {
+		if (strcmp(system->name, name) == 0)
+			return system->entry;
+	}
+
+	/* need to create new entry */
+	system = kmalloc(sizeof(*system), GFP_KERNEL);
+	if (!system) {
+		pr_warning("No memory to create event subsystem %s\n",
+			   name);
+		return d_events;
+	}
+
+	system->entry = debugfs_create_dir(name, d_events);
+	if (!system->entry) {
+		pr_warning("Could not create event subsystem %s\n",
+			   name);
+		kfree(system);
+		return d_events;
+	}
+
+	system->name = name;
+	list_add(&system->list, &event_subsystems);
+
+	return system->entry;
+}
+
+static int
+event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
+{
+	struct dentry *entry;
+	int ret;
+
+	/*
+	 * If the trace point header did not define TRACE_SYSTEM
+	 * then the system would be called "TRACE_SYSTEM".
+	 */
+	if (strcmp(call->system, "TRACE_SYSTEM") != 0)
+		d_events = event_subsystem_dir(call->system, d_events);
+
+	if (call->raw_init) {
+		ret = call->raw_init();
+		if (ret < 0) {
+			pr_warning("Could not initialize trace point"
+				   " events/%s\n", call->name);
+			return ret;
+		}
+	}
+
+	/* default the output to printf */
+	call->type = TRACE_EVENT_TYPE_PRINTF;
+
+	call->dir = debugfs_create_dir(call->name, d_events);
+	if (!call->dir) {
+		pr_warning("Could not create debugfs "
+			   "'%s' directory\n", call->name);
+		return -1;
+	}
+
+	entry = debugfs_create_file("enable", 0644, call->dir, call,
+				    &ftrace_enable_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'%s/enable' entry\n", call->name);
+
+	/* Only let type be writable, if we can change it */
+	entry = debugfs_create_file("type",
+				    call->raw_init ? 0644 : 0444,
+				    call->dir, call,
+				    &ftrace_type_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'%s/type' entry\n", call->name);
+
+	entry = debugfs_create_file("available_types", 0444, call->dir, call,
+				    &ftrace_available_types_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'%s/available_types' entry\n", call->name);
+
+	/* A trace may not want to export its format */
+	if (!call->show_format)
+		return 0;
+
+	entry = debugfs_create_file("format", 0444, call->dir, call,
+				    &ftrace_event_format_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'%s/format' entry\n", call->name);
+
+	return 0;
+}
+
+static __init int event_trace_init(void)
+{
+	struct ftrace_event_call *call = __start_ftrace_events;
+	struct dentry *d_tracer;
+	struct dentry *entry;
+	struct dentry *d_events;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	entry = debugfs_create_file("available_events", 0444, d_tracer,
+				    (void *)&show_event_seq_ops,
+				    &ftrace_avail_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'available_events' entry\n");
+
+	entry = debugfs_create_file("set_event", 0644, d_tracer,
+				    (void *)&show_set_event_seq_ops,
+				    &ftrace_set_event_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'set_event' entry\n");
+
+	d_events = event_trace_events_dir();
+	if (!d_events)
+		return 0;
+
+	events_for_each(call) {
+		/* The linker may leave blanks */
+		if (!call->name)
+			continue;
+		event_create_dir(call, d_events);
+	}
+
+	return 0;
+}
+fs_initcall(event_trace_init);