tracing: Add enabling of events to boot instances

Add the format of:

  trace_instance=foo,sched:sched_switch,irq_handler_entry,initcall

That will create the "foo" instance and enable the sched_switch event
(here were the "sched" system is explicitly specified), the
irq_handler_entry event, and all events under the system initcall.

Link: https://lkml.kernel.org/r/20230207173026.386114535@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 863716fcca49..5b16af9e7d30 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10188,6 +10188,10 @@ __init static void enable_instances(void)
 		}
 		/* Allow user space to delete it */
 		trace_array_put(tr);
+
+		while ((tok = strsep(&curr_str, ","))) {
+			early_enable_events(tr, tok, true);
+		}
 	}
 }