[for-next][PATCH 11/21] tracing: Allow for modules to convert their enums to values

From: Steven Rostedt
Date: Wed Apr 08 2015 - 09:51:59 EST


From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>

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@xxxxxxxxxxxxxxx

Acked-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
include/linux/module.h | 2 ++
kernel/module.c | 3 +++
kernel/trace/trace.c | 49 +++++++++++++++++++++++++++++++++++++++++----
kernel/trace/trace_events.c | 2 +-
4 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 42999fe2dbd0..53dc41dd5c62 100644
--- 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 b3d634ed06c9..d8f8ab271c2b 100644
--- 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 ebf49649534c..28e6654e640d 100644
--- 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 fc58c50fbf01..a576bbe75577 100644
--- 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 */

--
2.1.4


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/