1 files changed, 407 insertions, 0 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
new file mode 100644
index 0000000..3bcb9df
--- /dev/null
+++ b/kernel/trace/trace_events.c
@@ -0,0 +1,407 @@
+/*
+ * event tracer
+ *
+ * Copyright (C) 2008 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+
+#include "trace_events.h"
+
+#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 int ftrace_set_clr_event(char *buf, int set)
+{
+	struct ftrace_event_call *call = __start_ftrace_events;
+
+
+	events_for_each(call) {
+
+		if (!call->name)
+			continue;
+
+		if (strcmp(buf, call->name) != 0)
+			continue;
+
+		if (set) {
+			/* Already set? */
+			if (call->enabled)
+				return 0;
+			call->enabled = 1;
+			call->regfunc();
+		} else {
+			/* Already cleared? */
+			if (!call->enabled)
+				return 0;
+			call->enabled = 0;
+			call->unregfunc();
+		}
+		return 0;
+	}
+	return -EINVAL;
+}
+
+/* 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;
+
+	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)
+		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:
+		if (!call->enabled)
+			break;
+
+		call->enabled = 0;
+		call->unregfunc();
+		break;
+	case 1:
+		if (call->enabled)
+			break;
+
+		call->enabled = 1;
+		call->regfunc();
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+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 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;
+}
+
+static int
+event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
+{
+	struct dentry *entry;
+
+	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);
+
+	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);