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Commit 6d723736 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
Browse files

tracing/events: add support for modules to TRACE_EVENT 



Impact: allow modules to add TRACE_EVENTS on load

This patch adds the final hooks to allow modules to use the TRACE_EVENT
macro. A notifier and a data structure are used to link the TRACE_EVENTs
defined in the module to connect them with the ftrace event tracing system.

It also adds the necessary automated clean ups to the trace events when a
module is removed.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 17c873ec

include/linux/ftrace_event.h

+3 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 


struct trace_array;

struct tracer;

struct dentry;



/*

 * The trace entry - the most basic unit of tracing. This is what
@@ -87,6 +88,7 @@ struct ftrace_event_call { 
	char			*name;

	char			*system;

	struct dentry		*dir;

	struct trace_event	*event;

	int			enabled;

	int			(*regfunc)(void);

	void			(*unregfunc)(void);
@@ -97,6 +99,7 @@ struct ftrace_event_call { 
	struct list_head	fields;

	int			n_preds;

	struct filter_pred	**preds;

	void			*mod;



#ifdef CONFIG_EVENT_PROFILE

	atomic_t	profile_count;

include/linux/module.h

+4 −0
Original line number Diff line number Diff line
@@ -337,6 +337,10 @@ struct module 
	const char **trace_bprintk_fmt_start;

	unsigned int num_trace_bprintk_fmt;

#endif

#ifdef CONFIG_EVENT_TRACING

	struct ftrace_event_call *trace_events;

	unsigned int num_trace_events;

#endif



#ifdef CONFIG_MODULE_UNLOAD

	/* What modules depend on me? */

include/linux/trace_seq.h

+2 −0
Original line number Diff line number Diff line 
#ifndef _LINUX_TRACE_SEQ_H

#define _LINUX_TRACE_SEQ_H



#include <linux/fs.h>



/*

 * Trace sequences are used to allow a function to call several other functions

 * to create a string of data to use (up to a max of PAGE_SIZE.

include/trace/ftrace.h

+1 −0
Original line number Diff line number Diff line
@@ -477,6 +477,7 @@ __attribute__((__aligned__(4))) \ 
__attribute__((section("_ftrace_events"))) event_##call = {		\

	.name			= #call,				\

	.system			= __stringify(TRACE_SYSTEM),		\

	.event			= &ftrace_event_type_##call,		\

	.raw_init		= ftrace_raw_init_event_##call,		\

	.regfunc		= ftrace_raw_reg_event_##call,		\

	.unregfunc		= ftrace_raw_unreg_event_##call,	\

kernel/module.c

+7 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
*/

#include <linux/module.h>

#include <linux/moduleloader.h>

#include <linux/ftrace_event.h>

#include <linux/init.h>

#include <linux/kallsyms.h>

#include <linux/fs.h>
@@ -2172,6 +2173,12 @@ static noinline struct module *load_module(void __user *umod, 
					sizeof(*mod->tracepoints),

					&mod->num_tracepoints);

#endif

#ifdef CONFIG_EVENT_TRACING

	mod->trace_events = section_objs(hdr, sechdrs, secstrings,

					 "_ftrace_events",

					 sizeof(*mod->trace_events),

					 &mod->num_trace_events);

#endif



#ifdef CONFIG_MODVERSIONS

	if ((mod->num_syms && !mod->crcs)