[RFC][PATCH 1/5] ftrace: Add a ftrace_free_mem() function for modules to use

[Steven Rostedt]

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

In order to be able to trace module init functions, the module code needs to
tell ftrace what is being freed when the init sections are freed. Use the
code that the main init calls to tell ftrace to free the main init sections.
This requires passing in a start and end address to free.

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
 include/linux/ftrace.h |  2 ++
 kernel/trace/ftrace.c  | 14 +++++++++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 2e028854bac7..47fc404ad233 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -151,8 +151,10 @@ struct ftrace_ops_hash {
 };
 
 void ftrace_free_init_mem(void);
+void ftrace_free_mem(void *start, void *end);
 #else
 static inline void ftrace_free_init_mem(void) { }
+static inline void ftrace_free_mem(void *start, void *end) { }
 #endif
 
 /*
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6abfafd7f173..84cb5928665a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5868,10 +5868,10 @@ void ftrace_module_init(struct module *mod)
 }
 #endif /* CONFIG_MODULES */
 
-void __init ftrace_free_init_mem(void)
+void ftrace_free_mem(void *start_ptr, void *end_ptr)
 {
-	unsigned long start = (unsigned long)(&__init_begin);
-	unsigned long end = (unsigned long)(&__init_end);
+	unsigned long start = (unsigned long)(start_ptr);
+	unsigned long end = (unsigned long)(end_ptr);
 	struct ftrace_page **last_pg = &ftrace_pages_start;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
@@ -5913,6 +5913,14 @@ void __init ftrace_free_init_mem(void)
 	mutex_unlock(&ftrace_lock);
 }
 
+void __init ftrace_free_init_mem(void)
+{
+	void *start = (void *)(&__init_begin);
+	void *end = (void *)(&__init_end);
+
+	ftrace_free_mem(start, end);
+}
+
 void __init ftrace_init(void)
 {
 	extern unsigned long __start_mcount_loc[];
-- 
2.13.2