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Commit 33ea4b24 authored by Song Liu's avatar Song Liu Committed by Ingo Molnar
Browse files

perf/core: Implement the 'perf_uprobe' PMU 



This patch adds perf_uprobe support with similar pattern as previous
patch (for kprobe).

Two functions, create_local_trace_uprobe() and
destroy_local_trace_uprobe(), are created so a uprobe can be created
and attached to the file descriptor created by perf_event_open().

Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarYonghong Song <yhs@fb.com>
Reviewed-by: default avatarJosef Bacik <jbacik@fb.com>
Cc: <daniel@iogearbox.net>
Cc: <davem@davemloft.net>
Cc: <kernel-team@fb.com>
Cc: <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171206224518.3598254-7-songliubraving@fb.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e12f03d7

include/linux/trace_events.h

+4 −0
Original line number Diff line number Diff line
@@ -537,6 +537,10 @@ extern void perf_trace_del(struct perf_event *event, int flags); 
extern int  perf_kprobe_init(struct perf_event *event, bool is_retprobe);

extern void perf_kprobe_destroy(struct perf_event *event);

#endif

#ifdef CONFIG_UPROBE_EVENTS

extern int  perf_uprobe_init(struct perf_event *event, bool is_retprobe);

extern void perf_uprobe_destroy(struct perf_event *event);

#endif

extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,

				     char *filter_str);

extern void ftrace_profile_free_filter(struct perf_event *event);

kernel/events/core.c

+47 −1
Original line number Diff line number Diff line
@@ -7992,7 +7992,7 @@ static struct pmu perf_tracepoint = { 
	.read		= perf_swevent_read,

};



#ifdef CONFIG_KPROBE_EVENTS

#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)

/*

 * Flags in config, used by dynamic PMU kprobe and uprobe

 * The flags should match following PMU_FORMAT_ATTR().
@@ -8020,7 +8020,9 @@ static const struct attribute_group *probe_attr_groups[] = { 
	&probe_format_group,

	NULL,

};

#endif



#ifdef CONFIG_KPROBE_EVENTS

static int perf_kprobe_event_init(struct perf_event *event);

static struct pmu perf_kprobe = {

	.task_ctx_nr	= perf_sw_context,
@@ -8057,12 +8059,52 @@ static int perf_kprobe_event_init(struct perf_event *event) 
}

#endif /* CONFIG_KPROBE_EVENTS */



#ifdef CONFIG_UPROBE_EVENTS

static int perf_uprobe_event_init(struct perf_event *event);

static struct pmu perf_uprobe = {

	.task_ctx_nr	= perf_sw_context,

	.event_init	= perf_uprobe_event_init,

	.add		= perf_trace_add,

	.del		= perf_trace_del,

	.start		= perf_swevent_start,

	.stop		= perf_swevent_stop,

	.read		= perf_swevent_read,

	.attr_groups	= probe_attr_groups,

};



static int perf_uprobe_event_init(struct perf_event *event)

{

	int err;

	bool is_retprobe;



	if (event->attr.type != perf_uprobe.type)

		return -ENOENT;

	/*

	 * no branch sampling for probe events

	 */

	if (has_branch_stack(event))

		return -EOPNOTSUPP;



	is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;

	err = perf_uprobe_init(event, is_retprobe);

	if (err)

		return err;



	event->destroy = perf_uprobe_destroy;



	return 0;

}

#endif /* CONFIG_UPROBE_EVENTS */



static inline void perf_tp_register(void)

{

	perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);

#ifdef CONFIG_KPROBE_EVENTS

	perf_pmu_register(&perf_kprobe, "kprobe", -1);

#endif

#ifdef CONFIG_UPROBE_EVENTS

	perf_pmu_register(&perf_uprobe, "uprobe", -1);

#endif

}



static void perf_event_free_filter(struct perf_event *event)
@@ -8150,6 +8192,10 @@ static inline bool perf_event_is_tracing(struct perf_event *event) 
#ifdef CONFIG_KPROBE_EVENTS

	if (event->pmu == &perf_kprobe)

		return true;

#endif

#ifdef CONFIG_UPROBE_EVENTS

	if (event->pmu == &perf_uprobe)

		return true;

#endif

	return false;

}

kernel/trace/trace_event_perf.c

+53 −0
Original line number Diff line number Diff line
@@ -286,6 +286,59 @@ void perf_kprobe_destroy(struct perf_event *p_event) 
}

#endif /* CONFIG_KPROBE_EVENTS */



#ifdef CONFIG_UPROBE_EVENTS

int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe)

{

	int ret;

	char *path = NULL;

	struct trace_event_call *tp_event;



	if (!p_event->attr.uprobe_path)

		return -EINVAL;

	path = kzalloc(PATH_MAX, GFP_KERNEL);

	if (!path)

		return -ENOMEM;

	ret = strncpy_from_user(

		path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);

	if (ret < 0)

		goto out;

	if (path[0] == '\0') {

		ret = -EINVAL;

		goto out;

	}



	tp_event = create_local_trace_uprobe(

		path, p_event->attr.probe_offset, is_retprobe);

	if (IS_ERR(tp_event)) {

		ret = PTR_ERR(tp_event);

		goto out;

	}



	/*

	 * local trace_uprobe need to hold event_mutex to call

	 * uprobe_buffer_enable() and uprobe_buffer_disable().

	 * event_mutex is not required for local trace_kprobes.

	 */

	mutex_lock(&event_mutex);

	ret = perf_trace_event_init(tp_event, p_event);

	if (ret)

		destroy_local_trace_uprobe(tp_event);

	mutex_unlock(&event_mutex);

out:

	kfree(path);

	return ret;

}



void perf_uprobe_destroy(struct perf_event *p_event)

{

	mutex_lock(&event_mutex);

	perf_trace_event_close(p_event);

	perf_trace_event_unreg(p_event);

	mutex_unlock(&event_mutex);

	destroy_local_trace_uprobe(p_event->tp_event);

}

#endif /* CONFIG_UPROBE_EVENTS */



int perf_trace_add(struct perf_event *p_event, int flags)

{

	struct trace_event_call *tp_event = p_event->tp_event;

kernel/trace/trace_probe.h

+4 −0
Original line number Diff line number Diff line
@@ -410,4 +410,8 @@ extern struct trace_event_call * 
create_local_trace_kprobe(char *func, void *addr, unsigned long offs,

			  bool is_return);

extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);



extern struct trace_event_call *

create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);

extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);

#endif

kernel/trace/trace_uprobe.c

+78 −8
Original line number Diff line number Diff line
@@ -1292,16 +1292,25 @@ static struct trace_event_functions uprobe_funcs = { 
	.trace		= print_uprobe_event

};



static int register_uprobe_event(struct trace_uprobe *tu)

static inline void init_trace_event_call(struct trace_uprobe *tu,

					 struct trace_event_call *call)

{

	struct trace_event_call *call = &tu->tp.call;

	int ret;



	/* Initialize trace_event_call */

	INIT_LIST_HEAD(&call->class->fields);

	call->event.funcs = &uprobe_funcs;

	call->class->define_fields = uprobe_event_define_fields;



	call->flags = TRACE_EVENT_FL_UPROBE;

	call->class->reg = trace_uprobe_register;

	call->data = tu;

}



static int register_uprobe_event(struct trace_uprobe *tu)

{

	struct trace_event_call *call = &tu->tp.call;

	int ret = 0;



	init_trace_event_call(tu, call);



	if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)

		return -ENOMEM;
@@ -1311,9 +1320,6 @@ static int register_uprobe_event(struct trace_uprobe *tu) 
		return -ENODEV;

	}



	call->flags = TRACE_EVENT_FL_UPROBE;

	call->class->reg = trace_uprobe_register;

	call->data = tu;

	ret = trace_add_event_call(call);



	if (ret) {
@@ -1339,6 +1345,70 @@ static int unregister_uprobe_event(struct trace_uprobe *tu) 
	return 0;

}



#ifdef CONFIG_PERF_EVENTS

struct trace_event_call *

create_local_trace_uprobe(char *name, unsigned long offs, bool is_return)

{

	struct trace_uprobe *tu;

	struct inode *inode;

	struct path path;

	int ret;



	ret = kern_path(name, LOOKUP_FOLLOW, &path);

	if (ret)

		return ERR_PTR(ret);



	inode = igrab(d_inode(path.dentry));

	path_put(&path);



	if (!inode || !S_ISREG(inode->i_mode)) {

		iput(inode);

		return ERR_PTR(-EINVAL);

	}



	/*

	 * local trace_kprobes are not added to probe_list, so they are never

	 * searched in find_trace_kprobe(). Therefore, there is no concern of

	 * duplicated name "DUMMY_EVENT" here.

	 */

	tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,

				is_return);



	if (IS_ERR(tu)) {

		pr_info("Failed to allocate trace_uprobe.(%d)\n",

			(int)PTR_ERR(tu));

		return ERR_CAST(tu);

	}



	tu->offset = offs;

	tu->inode = inode;

	tu->filename = kstrdup(name, GFP_KERNEL);

	init_trace_event_call(tu, &tu->tp.call);



	if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {

		ret = -ENOMEM;

		goto error;

	}



	return &tu->tp.call;

error:

	free_trace_uprobe(tu);

	return ERR_PTR(ret);

}



void destroy_local_trace_uprobe(struct trace_event_call *event_call)

{

	struct trace_uprobe *tu;



	tu = container_of(event_call, struct trace_uprobe, tp.call);



	kfree(tu->tp.call.print_fmt);

	tu->tp.call.print_fmt = NULL;



	free_trace_uprobe(tu);

}

#endif /* CONFIG_PERF_EVENTS */



/* Make a trace interface for controling probe points */

static __init int init_uprobe_trace(void)

{