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Commit e08d1c65 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
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tracing/kprobes: Add event profiling support 



Add *probe_profile_enable/disable to support kprobes raw events
sampling from perf counters, like other ftrace events, when
CONFIG_PROFILE_EVENT=y.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
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: Frederic Weisbecker <fweisbec@gmail.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: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20090910235329.22412.94731.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 4a846b44

Documentation/trace/kprobetrace.txt

+3 −1
Original line number Diff line number Diff line
@@ -62,13 +62,15 @@ enabled: 
  You can enable/disable the probe by writing 1 or 0 on it.



format:

  It shows the format of this probe event. It also shows aliases of arguments

  This shows the format of this probe event. It also shows aliases of arguments

 which you specified to kprobe_events.



filter:

  You can write filtering rules of this event. And you can use both of aliase

 names and field names for describing filters.



id:

  This shows the id of this probe event.



Event Profiling

---------------

kernel/trace/trace_kprobe.c

+108 −2
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/string.h>

#include <linux/ctype.h>

#include <linux/ptrace.h>

#include <linux/perf_counter.h>



#include "trace.h"

#include "trace_output.h"
@@ -280,6 +281,7 @@ static struct trace_probe *alloc_trace_probe(const char *event, 
	} 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;

	else
@@ -929,11 +931,14 @@ static int probe_event_enable(struct ftrace_event_call *call) 
{

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



	if (probe_is_return(tp))

	if (probe_is_return(tp)) {

		tp->rp.handler = kretprobe_trace_func;

		return enable_kretprobe(&tp->rp);

	else

	} else {

		tp->rp.kp.pre_handler = kprobe_trace_func;

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

	}

}



static void probe_event_disable(struct ftrace_event_call *call)

{
@@ -1105,6 +1110,101 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call, 
					  "func, ret_ip");

}



#ifdef CONFIG_EVENT_PROFILE



/* Kprobe profile handler */

static __kprobes int kprobe_profile_func(struct kprobe *kp,

					 struct pt_regs *regs)

{

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

	struct ftrace_event_call *call = &tp->call;

	struct kprobe_trace_entry *entry;

	int size, i, pc;

	unsigned long irq_flags;



	local_save_flags(irq_flags);

	pc = preempt_count();



	size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);



	do {

		char raw_data[size];

		struct trace_entry *ent;



		*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;

		entry = (struct kprobe_trace_entry *)raw_data;

		ent = &entry->ent;



		tracing_generic_entry_update(ent, irq_flags, pc);

		ent->type = call->id;

		entry->nargs = tp->nr_args;

		entry->ip = (unsigned long)kp->addr;

		for (i = 0; i < tp->nr_args; i++)

			entry->args[i] = call_fetch(&tp->args[i], regs);

		perf_tpcounter_event(call->id, entry->ip, 1, entry, size);

	} while (0);

	return 0;

}



/* Kretprobe profile handler */

static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,

					    struct pt_regs *regs)

{

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

	struct ftrace_event_call *call = &tp->call;

	struct kretprobe_trace_entry *entry;

	int size, i, pc;

	unsigned long irq_flags;



	local_save_flags(irq_flags);

	pc = preempt_count();



	size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);



	do {

		char raw_data[size];

		struct trace_entry *ent;



		*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;

		entry = (struct kretprobe_trace_entry *)raw_data;

		ent = &entry->ent;



		tracing_generic_entry_update(ent, irq_flags, pc);

		ent->type = call->id;

		entry->nargs = tp->nr_args;

		entry->func = (unsigned long)tp->rp.kp.addr;

		entry->ret_ip = (unsigned long)ri->ret_addr;

		for (i = 0; i < tp->nr_args; i++)

			entry->args[i] = call_fetch(&tp->args[i], regs);

		perf_tpcounter_event(call->id, entry->ret_ip, 1, entry, size);

	} while (0);

	return 0;

}



static int probe_profile_enable(struct ftrace_event_call *call)

{

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



	if (atomic_inc_return(&call->profile_count))

		return 0;



	if (probe_is_return(tp)) {

		tp->rp.handler = kretprobe_profile_func;

		return enable_kretprobe(&tp->rp);

	} else {

		tp->rp.kp.pre_handler = kprobe_profile_func;

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

	}

}



static void probe_profile_disable(struct ftrace_event_call *call)

{

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

		probe_event_disable(call);

}



#endif	/* CONFIG_EVENT_PROFILE */



static int register_probe_event(struct trace_probe *tp)

{

	struct ftrace_event_call *call = &tp->call;
@@ -1130,6 +1230,12 @@ static int register_probe_event(struct trace_probe *tp) 
	call->enabled = 1;

	call->regfunc = probe_event_enable;

	call->unregfunc = probe_event_disable;



#ifdef CONFIG_EVENT_PROFILE

	atomic_set(&call->profile_count, -1);

	call->profile_enable = probe_profile_enable;

	call->profile_disable = probe_profile_disable;

#endif

	call->data = tp;

	ret = trace_add_event_call(call);

	if (ret) {