tracing: Enable records during the module load

[deliverable/linux.git] / kernel / trace / ftrace.c

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0c799d1af70209f90148a60239e90210c3db99c7..aaea9cda8781276a4f3d71d47089d1b0a7adb71e 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1270,12 +1270,34 @@ static int ftrace_update_code(struct module *mod)
                ftrace_new_addrs = p->newlist;
                p->flags = 0L;
 
-               /* convert record (i.e, patch mcount-call with NOP) */
-               if (ftrace_code_disable(mod, p)) {
-                       p->flags |= FTRACE_FL_CONVERTED;
-                       ftrace_update_cnt++;
-               } else
+               /*
+                * Do the initial record convertion from mcount jump
+                * to the NOP instructions.
+                */
+               if (!ftrace_code_disable(mod, p)) {
                        ftrace_free_rec(p);
+                       continue;
+               }
+
+               p->flags |= FTRACE_FL_CONVERTED;
+               ftrace_update_cnt++;
+
+               /*
+                * If the tracing is enabled, go ahead and enable the record.
+                *
+                * The reason not to enable the record immediatelly is the
+                * inherent check of ftrace_make_nop/ftrace_make_call for
+                * correct previous instructions.  Making first the NOP
+                * conversion puts the module to the correct state, thus
+                * passing the ftrace_make_call check.
+                */
+               if (ftrace_start_up) {
+                       int failed = __ftrace_replace_code(p, 1);
+                       if (failed) {
+                               ftrace_bug(failed, p->ip);
+                               ftrace_free_rec(p);
+                       }
+               }
        }
 
        stop = ftrace_now(raw_smp_processor_id());
@@ -2609,7 +2631,7 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
        return 0;
 }
 
-static int ftrace_convert_nops(struct module *mod,
+static int ftrace_process_locs(struct module *mod,
                               unsigned long *start,
                               unsigned long *end)
 {
@@ -2669,7 +2691,7 @@ static void ftrace_init_module(struct module *mod,
 {
        if (ftrace_disabled || start == end)
                return;
-       ftrace_convert_nops(mod, start, end);
+       ftrace_process_locs(mod, start, end);
 }
 
 static int ftrace_module_notify(struct notifier_block *self,
@@ -2730,7 +2752,7 @@ void __init ftrace_init(void)
 
        last_ftrace_enabled = ftrace_enabled = 1;
 
-       ret = ftrace_convert_nops(NULL,
+       ret = ftrace_process_locs(NULL,
                                  __start_mcount_loc,
                                  __stop_mcount_loc);