tracing: Allow for modules to convert their enums to values

Update the infrastructure such that modules that declare TRACE_DEFINE_ENUM()
will have those enums converted into their values in the tracepoint
print fmt strings.

Link: http://lkml.kernel.org/r/87vbhjp74q.fsf@rustcorp.com.au
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/module.h b/include/linux/module.h
index 42999fe2dbd0fb8ec057dbd07d4c2143d6225c65..53dc41dd5c62aad771db7f9a4f63f2a7858e9b28 100644 (file)
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -338,6 +338,8 @@ struct module {
 #ifdef CONFIG_EVENT_TRACING
        struct ftrace_event_call **trace_events;
        unsigned int num_trace_events;
+       struct trace_enum_map **trace_enums;
+       unsigned int num_trace_enums;
 #endif
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
        unsigned int num_ftrace_callsites;

diff --git a/kernel/module.c b/kernel/module.c
index b3d634ed06c94f1b2ce986293d0cda84078d4a46..d8f8ab271c2b93910cf994486e743a36338b44d2 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2753,6 +2753,9 @@ static int find_module_sections(struct module *mod, struct load_info *info)
        mod->trace_events = section_objs(info, "_ftrace_events",
                                         sizeof(*mod->trace_events),
                                         &mod->num_trace_events);
+       mod->trace_enums = section_objs(info, "_ftrace_enum_map",
+                                       sizeof(*mod->trace_enums),
+                                       &mod->num_trace_enums);
 #endif
 #ifdef CONFIG_TRACING
        mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ebf49649534c6854b27ad95ceee44e86ce34b1d0..28e6654e640d82e0f486ced6d8b32d28ed715470 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3908,11 +3908,9 @@ static const struct file_operations tracing_saved_cmdlines_size_fops = {
        .write          = tracing_saved_cmdlines_size_write,
 };
 
-static void
-trace_insert_enum_map(struct trace_enum_map **start, struct trace_enum_map **stop)
+static void trace_insert_enum_map(struct trace_enum_map **start, int len)
 {
        struct trace_enum_map **map;
-       int len = stop - start;
 
        if (len <= 0)
                return;
@@ -6561,9 +6559,48 @@ extern struct trace_enum_map *__stop_ftrace_enum_maps[];
 
 static void __init trace_enum_init(void)
 {
-       trace_insert_enum_map(__start_ftrace_enum_maps, __stop_ftrace_enum_maps);
+       int len;
+
+       len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
+       trace_insert_enum_map(__start_ftrace_enum_maps, len);
+}
+
+#ifdef CONFIG_MODULES
+static void trace_module_add_enums(struct module *mod)
+{
+       if (!mod->num_trace_enums)
+               return;
+
+       /*
+        * Modules with bad taint do not have events created, do
+        * not bother with enums either.
+        */
+       if (trace_module_has_bad_taint(mod))
+               return;
+
+       trace_insert_enum_map(mod->trace_enums, mod->num_trace_enums);
+}
+
+static int trace_module_notify(struct notifier_block *self,
+                              unsigned long val, void *data)
+{
+       struct module *mod = data;
+
+       switch (val) {
+       case MODULE_STATE_COMING:
+               trace_module_add_enums(mod);
+               break;
+       }
+
+       return 0;
 }
 
+static struct notifier_block trace_module_nb = {
+       .notifier_call = trace_module_notify,
+       .priority = 0,
+};
+#endif
+
 static __init int tracer_init_debugfs(void)
 {
        struct dentry *d_tracer;
@@ -6590,6 +6627,10 @@ static __init int tracer_init_debugfs(void)
 
        trace_enum_init();
 
+#ifdef CONFIG_MODULES
+       register_module_notifier(&trace_module_nb);
+#endif
+
 #ifdef CONFIG_DYNAMIC_FTRACE
        trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
                        &ftrace_update_tot_cnt, &tracing_dyn_info_fops);

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index fc58c50fbf0141eceadf90a56a6e731e25314fec..a576bbe75577e9e3d6896a2bc54b9fd98c8407e5 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2034,7 +2034,7 @@ static int trace_module_notify(struct notifier_block *self,
 
 static struct notifier_block trace_module_nb = {
        .notifier_call = trace_module_notify,
-       .priority = 0,
+       .priority = 1, /* higher than trace.c module notify */
 };
 #endif /* CONFIG_MODULES */