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Commit 50d78056 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
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tracing/kprobes: Add probe handler dispatcher to support perf and ftrace concurrent use 



Add kprobe_dispatcher and kretprobe_dispatcher to dispatch event
in both profile and tracing handlers.

This allows simultaneous kprobe uses by ftrace and perf.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090914204920.18779.57555.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 4fead8e4

kernel/trace/trace_kprobe.c

+63 −22
Original line number Diff line number Diff line
@@ -185,10 +185,15 @@ struct probe_arg { 
	const char		*name;

};



/* Flags for trace_probe */

#define TP_FLAG_TRACE	1

#define TP_FLAG_PROFILE	2



struct trace_probe {

	struct list_head	list;

	struct kretprobe	rp;	/* Use rp.kp for kprobe use */

	unsigned long 		nhit;

	unsigned int		flags;	/* For TP_FLAG_* */

	const char		*symbol;	/* symbol name */

	struct ftrace_event_call	call;

	struct trace_event		event;
@@ -200,10 +205,6 @@ struct trace_probe { 
	(offsetof(struct trace_probe, args) +	\

	(sizeof(struct probe_arg) * (n)))



static int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs);

static int kretprobe_trace_func(struct kretprobe_instance *ri,

				struct pt_regs *regs);



static __kprobes int probe_is_return(struct trace_probe *tp)

{

	return tp->rp.handler != NULL;
@@ -263,6 +264,10 @@ static void unregister_probe_event(struct trace_probe *tp); 
static DEFINE_MUTEX(probe_lock);

static LIST_HEAD(probe_list);



static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);

static int kretprobe_dispatcher(struct kretprobe_instance *ri,

				struct pt_regs *regs);



/*

 * Allocate new trace_probe and initialize it (including kprobes).

 */
@@ -288,11 +293,10 @@ static struct trace_probe *alloc_trace_probe(const char *group, 
	} else

		tp->rp.kp.addr = addr;



	/* Set handler here for checking whether this probe is return or not. */

	if (is_return)

		tp->rp.handler = kretprobe_trace_func;

		tp->rp.handler = kretprobe_dispatcher;

	else

		tp->rp.kp.pre_handler = kprobe_trace_func;

		tp->rp.kp.pre_handler = kprobe_dispatcher;



	if (!event)

		goto error;
@@ -379,6 +383,7 @@ static int register_trace_probe(struct trace_probe *tp) 
		goto end;

	}



	tp->flags = TP_FLAG_TRACE;

	if (probe_is_return(tp))

		ret = register_kretprobe(&tp->rp);

	else
@@ -987,24 +992,25 @@ static int probe_event_enable(struct ftrace_event_call *call) 
{

	struct trace_probe *tp = (struct trace_probe *)call->data;



	if (probe_is_return(tp)) {

		tp->rp.handler = kretprobe_trace_func;

	tp->flags |= TP_FLAG_TRACE;

	if (probe_is_return(tp))

		return enable_kretprobe(&tp->rp);

	} else {

		tp->rp.kp.pre_handler = kprobe_trace_func;

	else

		return enable_kprobe(&tp->rp.kp);

}

}



static void probe_event_disable(struct ftrace_event_call *call)

{

	struct trace_probe *tp = (struct trace_probe *)call->data;



	tp->flags &= ~TP_FLAG_TRACE;

	if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {

		if (probe_is_return(tp))

			disable_kretprobe(&tp->rp);

		else

			disable_kprobe(&tp->rp.kp);

	}

}



static int probe_event_raw_init(struct ftrace_event_call *event_call)

{
@@ -1212,22 +1218,57 @@ static int probe_profile_enable(struct ftrace_event_call *call) 
	if (atomic_inc_return(&call->profile_count))

		return 0;



	if (probe_is_return(tp)) {

		tp->rp.handler = kretprobe_profile_func;

	tp->flags |= TP_FLAG_PROFILE;

	if (probe_is_return(tp))

		return enable_kretprobe(&tp->rp);

	} else {

		tp->rp.kp.pre_handler = kprobe_profile_func;

	else

		return enable_kprobe(&tp->rp.kp);

}

}



static void probe_profile_disable(struct ftrace_event_call *call)

{

	struct trace_probe *tp = (struct trace_probe *)call->data;



	if (atomic_add_negative(-1, &call->profile_count))

		probe_event_disable(call);

		tp->flags &= ~TP_FLAG_PROFILE;



	if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {

		if (probe_is_return(tp))

			disable_kretprobe(&tp->rp);

		else

			disable_kprobe(&tp->rp.kp);

	}

}

#endif	/* CONFIG_EVENT_PROFILE */





static __kprobes

int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)

{

	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);



	if (tp->flags & TP_FLAG_TRACE)

		kprobe_trace_func(kp, regs);

#ifdef CONFIG_EVENT_PROFILE

	if (tp->flags & TP_FLAG_PROFILE)

		kprobe_profile_func(kp, regs);

#endif	/* CONFIG_EVENT_PROFILE */

	return 0;	/* We don't tweek kernel, so just return 0 */

}



static __kprobes

int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)

{

	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);



	if (tp->flags & TP_FLAG_TRACE)

		kretprobe_trace_func(ri, regs);

#ifdef CONFIG_EVENT_PROFILE

	if (tp->flags & TP_FLAG_PROFILE)

		kretprobe_profile_func(ri, regs);

#endif	/* CONFIG_EVENT_PROFILE */

	return 0;	/* We don't tweek kernel, so just return 0 */

}



static int register_probe_event(struct trace_probe *tp)

{