1 files changed, 77 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 961b057da28b..97470c48956e 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -459,6 +459,71 @@ event_id_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
         return r;
 }
 
+static ssize_t
+event_filter_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;
+        int r;
+
+        if (*ppos)
+                return 0;
+
+        s = kmalloc(sizeof(*s), GFP_KERNEL);
+        if (!s)
+                return -ENOMEM;
+
+        trace_seq_init(s);
+
+        r = filter_print_preds(call->preds, s->buffer);
+        r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, r);
+
+        kfree(s);
+
+        return r;
+}
+
+static ssize_t
+event_filter_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], *pbuf = buf;
+        struct filter_pred *pred;
+        int err;
+
+        if (cnt >= sizeof(buf))
+                return -EINVAL;
+
+        if (copy_from_user(&buf, ubuf, cnt))
+                return -EFAULT;
+
+        pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+        if (!pred)
+                return -ENOMEM;
+
+        err = filter_parse(&pbuf, pred);
+        if (err < 0) {
+                filter_free_pred(pred);
+                return err;
+        }
+
+        if (pred->clear) {
+                filter_free_preds(call);
+                return cnt;
+        }
+
+        if (filter_add_pred(call, pred)) {
+                filter_free_pred(pred);
+                return -EINVAL;
+        }
+
+        *ppos += cnt;
+
+        return cnt;
+}
+
 static const struct seq_operations show_event_seq_ops = {
         .start = t_start,
         .next = t_next,
@@ -504,6 +569,12 @@ static const struct file_operations ftrace_event_id_fops = {
         .read = event_id_read,
 };
 
+static const struct file_operations ftrace_event_filter_fops = {
+        .open = tracing_open_generic,
+        .read = event_filter_read,
+        .write = event_filter_write,
+};
+
 static struct dentry *event_trace_events_dir(void)
 {
         static struct dentry *d_tracer;
@@ -619,6 +690,12 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
                 }
         }
 
+        entry = debugfs_create_file("filter", 0444, call->dir, call,
+                                    &ftrace_event_filter_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'%s/filter' entry\n", call->name);
+
         /* A trace may not want to export its format */
         if (!call->show_format)
                 return 0;