tracing/ftrace: make tracing suitable to run the boot tracer

The tracing engine have now to be init in early_initcall to set the
boot tracer. Only the debugfs settings will be initialized at
fs_initcall time.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 5 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f2ef72fa3f17..6ada059832a6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2990,7 +2990,7 @@ struct dentry *tracing_init_dentry(void)
 #include "trace_selftest.c"
 #endif
 
-static __init void tracer_init_debugfs(void)
+static __init int tracer_init_debugfs(void)
 {
         struct dentry *d_tracer;
         struct dentry *entry;
@@ -3078,6 +3078,7 @@ static __init void tracer_init_debugfs(void)
 #ifdef CONFIG_SYSPROF_TRACER
         init_tracer_sysprof_debugfs(d_tracer);
 #endif
+        return 0;
 }
 
 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
@@ -3504,17 +3505,20 @@ __init static int tracer_alloc_buffers(void)
                 pages, trace_nr_entries, (long)TRACE_ENTRY_SIZE);
         pr_info("   actual entries %ld\n", global_trace.entries);
 
-        tracer_init_debugfs();
-
         trace_init_cmdlines();
 
         register_tracer(&nop_trace);
+#ifdef CONFIG_BOOT_TRACER
+        register_tracer(&boot_tracer);
+        current_trace = &boot_tracer;
+        current_trace->init(&global_trace);
+#else
         current_trace = &nop_trace;
+#endif
 
         /* All seems OK, enable tracing */
         global_trace.ctrl = tracer_enabled;
         tracing_disabled = 0;
-
         atomic_notifier_chain_register(&panic_notifier_list,
                                        &trace_panic_notifier);
 
@@ -3548,4 +3552,5 @@ __init static int tracer_alloc_buffers(void)
         }
         return ret;
 }
-fs_initcall(tracer_alloc_buffers);
+early_initcall(tracer_alloc_buffers);
+fs_initcall(tracer_init_debugfs);