1 files changed, 140 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6d2c842a0248..87feb0117ce2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -400,6 +400,133 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
         return cnt;
 }
 
+static ssize_t
+system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
+                   loff_t *ppos)
+{
+        const char *system = filp->private_data;
+        struct ftrace_event_call *call;
+        char buf[2];
+        int set = -1;
+        int all = 0;
+        int ret;
+
+        if (system[0] == '*')
+                all = 1;
+
+        mutex_lock(&event_mutex);
+        list_for_each_entry(call, &ftrace_events, list) {
+                if (!call->name || !call->regfunc)
+                        continue;
+
+                if (!all && strcmp(call->system, system) != 0)
+                        continue;
+
+                /*
+                 * We need to find out if all the events are set
+                 * or if all events or cleared, or if we have
+                 * a mixture.
+                 */
+                if (call->enabled) {
+                        switch (set) {
+                        case -1:
+                                set = 1;
+                                break;
+                        case 0:
+                                set = 2;
+                                break;
+                        }
+                } else {
+                        switch (set) {
+                        case -1:
+                                set = 0;
+                                break;
+                        case 1:
+                                set = 2;
+                                break;
+                        }
+                }
+                /*
+                 * If we have a mixture, no need to look further.
+                 */
+                if (set == 2)
+                        break;
+        }
+        mutex_unlock(&event_mutex);
+
+        buf[1] = '\n';
+        switch (set) {
+        case 0:
+                buf[0] = '0';
+                break;
+        case 1:
+                buf[0] = '1';
+                break;
+        case 2:
+                buf[0] = 'X';
+                break;
+        default:
+                buf[0] = '?';
+        }
+
+        ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+
+        return ret;
+}
+
+static ssize_t
+system_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
+                    loff_t *ppos)
+{
+        const char *system = filp->private_data;
+        unsigned long val;
+        char *command;
+        char buf[64];
+        ssize_t 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;
+
+        ret = tracing_update_buffers();
+        if (ret < 0)
+                return ret;
+
+        switch (val) {
+        case 0:
+        case 1:
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        command = kstrdup(system, GFP_KERNEL);
+        if (!command)
+                return -ENOMEM;
+
+        ret = ftrace_set_clr_event(command, val);
+        if (ret)
+                goto out_free;
+
+        ret = cnt;
+
+ out_free:
+        kfree(command);
+
+        *ppos += cnt;
+
+        return ret;
+}
+
 extern char *__bad_type_size(void);
 
 #undef FIELD
@@ -686,6 +813,12 @@ static const struct file_operations ftrace_subsystem_filter_fops = {
         .write = subsystem_filter_write,
 };
 
+static const struct file_operations ftrace_system_enable_fops = {
+        .open = tracing_open_generic,
+        .read = system_enable_read,
+        .write = system_enable_write,
+};
+
 static const struct file_operations ftrace_show_header_fops = {
         .open = tracing_open_generic,
         .read = show_header,
@@ -768,6 +901,10 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
                            "'%s/filter' entry\n", name);
         }
 
+        entry = trace_create_file("enable", 0644, system->entry,
+                                  (void *)system->name,
+                                  &ftrace_system_enable_fops);
+
         return system->entry;
 }
 
@@ -1041,6 +1178,9 @@ static __init int event_trace_init(void)
                           ring_buffer_print_entry_header,
                           &ftrace_show_header_fops);
 
+        trace_create_file("enable", 0644, d_events,
+                          "*:*", &ftrace_system_enable_fops);
+
         for_each_event(call, __start_ftrace_events, __stop_ftrace_events) {
                 /* The linker may leave blanks */
                 if (!call->name)