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Commit a82378d8 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Frederic Weisbecker
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tracing: Kprobe-tracer supports more than 6 arguments 



Support up to 128 arguments to fetch for each kprobes event.

Signed-off-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.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: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203518.31965.96979.stgit@localhost.localdomain>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent d8ec9185

Documentation/trace/kprobetrace.txt

+1 −1
Original line number Original line Diff line number Diff line
@@ -32,7 +32,7 @@ Synopsis of kprobe_events 
 SYMBOL[+offs|-offs]	: Symbol+offset where the probe is inserted.

 SYMBOL[+offs|-offs]	: Symbol+offset where the probe is inserted.

 MEMADDR		: Address where the probe is inserted.

 MEMADDR		: Address where the probe is inserted.





 FETCHARGS		: Arguments.

 FETCHARGS		: Arguments. Each probe can have up to 128 args.

  %REG	: Fetch register REG

  %REG	: Fetch register REG

  sN	: Fetch Nth entry of stack (N >= 0)

  sN	: Fetch Nth entry of stack (N >= 0)

  sa	: Fetch stack address.

  sa	: Fetch stack address.

kernel/trace/trace_kprobe.c

+13 −8
Original line number Original line Diff line number Diff line
@@ -32,7 +32,7 @@ 
#include "trace.h"

#include "trace.h"

#include "trace_output.h"

#include "trace_output.h"





#define TRACE_KPROBE_ARGS 6

#define MAX_TRACE_ARGS 128

#define MAX_ARGSTR_LEN 63

#define MAX_ARGSTR_LEN 63





/* currently, trace_kprobe only supports X86. */

/* currently, trace_kprobe only supports X86. */
@@ -184,11 +184,15 @@ struct trace_probe { 
		struct kretprobe	rp;

		struct kretprobe	rp;

	};

	};

	const char		*symbol;	/* symbol name */

	const char		*symbol;	/* symbol name */

	unsigned int		nr_args;

	struct fetch_func	args[TRACE_KPROBE_ARGS];

	struct ftrace_event_call	call;

	struct ftrace_event_call	call;

	unsigned int		nr_args;

	struct fetch_func	args[];

};

};





#define SIZEOF_TRACE_PROBE(n)			\

	(offsetof(struct trace_probe, args) +	\

	(sizeof(struct fetch_func) * (n)))



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

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

static int kretprobe_trace_func(struct kretprobe_instance *ri,

static int kretprobe_trace_func(struct kretprobe_instance *ri,

				struct pt_regs *regs);

				struct pt_regs *regs);
@@ -263,11 +267,11 @@ static DEFINE_MUTEX(probe_lock); 
static LIST_HEAD(probe_list);

static LIST_HEAD(probe_list);





static struct trace_probe *alloc_trace_probe(const char *symbol,

static struct trace_probe *alloc_trace_probe(const char *symbol,

					     const char *event)

					     const char *event, int nargs)

{

{

	struct trace_probe *tp;

	struct trace_probe *tp;





	tp = kzalloc(sizeof(struct trace_probe), GFP_KERNEL);

	tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);

	if (!tp)

	if (!tp)

		return ERR_PTR(-ENOMEM);

		return ERR_PTR(-ENOMEM);
@@ -573,9 +577,10 @@ static int create_trace_probe(int argc, char **argv) 
		if (offset && is_return)

		if (offset && is_return)

			return -EINVAL;

			return -EINVAL;

	}

	}

	argc -= 2; argv += 2;





	/* setup a probe */

	/* setup a probe */

	tp = alloc_trace_probe(symbol, event);

	tp = alloc_trace_probe(symbol, event, argc);

	if (IS_ERR(tp))

	if (IS_ERR(tp))

		return PTR_ERR(tp);

		return PTR_ERR(tp);
@@ -594,8 +599,8 @@ static int create_trace_probe(int argc, char **argv) 
		kp->addr = addr;

		kp->addr = addr;





	/* parse arguments */

	/* parse arguments */

	argc -= 2; argv += 2; ret = 0;

	ret = 0;

	for (i = 0; i < argc && i < TRACE_KPROBE_ARGS; i++) {

	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {

		if (strlen(argv[i]) > MAX_ARGSTR_LEN) {

		if (strlen(argv[i]) > MAX_ARGSTR_LEN) {

			pr_info("Argument%d(%s) is too long.\n", i, argv[i]);

			pr_info("Argument%d(%s) is too long.\n", i, argv[i]);

			ret = -ENOSPC;

			ret = -ENOSPC;