1 files changed, 38 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f81d6eec4e43..7163a2bb021a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -610,6 +610,30 @@ subsystem_filter_write(struct file *filp, const char __user *ubuf, size_t cnt,
         return cnt;
 }
 
+static ssize_t
+show_header(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
+{
+        int (*func)(struct trace_seq *s) = filp->private_data;
+        struct trace_seq *s;
+        int r;
+
+        if (*ppos)
+                return 0;
+
+        s = kmalloc(sizeof(*s), GFP_KERNEL);
+        if (!s)
+                return -ENOMEM;
+
+        trace_seq_init(s);
+
+        func(s);
+        r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len);
+
+        kfree(s);
+
+        return r;
+}
+
 static const struct seq_operations show_event_seq_ops = {
         .start = t_start,
         .next = t_next,
@@ -667,6 +691,11 @@ static const struct file_operations ftrace_subsystem_filter_fops = {
         .write = subsystem_filter_write,
 };
 
+static const struct file_operations ftrace_show_header_fops = {
+        .open = tracing_open_generic,
+        .read = show_header,
+};
+
 static struct dentry *event_trace_events_dir(void)
 {
         static struct dentry *d_tracer;
@@ -909,6 +938,15 @@ static __init int event_trace_init(void)
         if (!d_events)
                 return 0;
 
+        /* ring buffer internal formats */
+        trace_create_file("header_page", 0444, d_events,
+                          ring_buffer_print_page_header,
+                          &ftrace_show_header_fops);
+
+        trace_create_file("header_event", 0444, d_events,
+                          ring_buffer_print_entry_header,
+                          &ftrace_show_header_fops);
+
         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
                 /* The linker may leave blanks */
                 if (!call->name)