[RFC][PATCH 2/5] ftrace: Allow module init functions to be traced

[Steven Rostedt]

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

Allow for module init sections to be traced as well as core kernel init
sections. Now that filtering modules functions can be stored, for when they
are loaded, it makes sense to be able to trace them.

Cc: Jessica Yu <jeyu@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 include/linux/init.h  | 4 +---
 kernel/module.c       | 2 ++
 kernel/trace/ftrace.c | 3 ++-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 94769d687cf0..a779c1816437 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -39,7 +39,7 @@
 
 /* These are for everybody (although not all archs will actually
    discard it in modules) */
-#define __init		__section(.init.text) __cold __inittrace __latent_entropy
+#define __init		__section(.init.text) __cold  __latent_entropy
 #define __initdata	__section(.init.data)
 #define __initconst	__section(.init.rodata)
 #define __exitdata	__section(.exit.data)
@@ -68,10 +68,8 @@
 
 #ifdef MODULE
 #define __exitused
-#define __inittrace notrace
 #else
 #define __exitused  __used
-#define __inittrace
 #endif
 
 #define __exit          __section(.exit.text) __exitused __cold notrace
diff --git a/kernel/module.c b/kernel/module.c
index 40f983cbea81..c1267ae10239 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3473,6 +3473,8 @@ static noinline int do_init_module(struct module *mod)
 	if (!mod->async_probe_requested && (current->flags & PF_USED_ASYNC))
 		async_synchronize_full();
 
+	ftrace_free_mem(mod->init_layout.base, mod->init_layout.base +
+			mod->init_layout.size);
 	mutex_lock(&module_mutex);
 	/* Drop initial reference. */
 	module_put(mod);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 84cb5928665a..7f7c56d532fd 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5821,7 +5821,8 @@ void ftrace_module_enable(struct module *mod)
 		 * not part of this module, then skip this pg,
 		 * which the "break" will do.
 		 */
-		if (!within_module_core(rec->ip, mod))
+		if (!within_module_core(rec->ip, mod) &&
+		    !within_module_init(rec->ip, mod))
 			break;
 
 		cnt = 0;
-- 
2.13.2