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Commit 469b9b88 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Add basic module support 



Add basic module probe support on perf probe. This introduces "--module
<MODNAME>" option to perf probe for putting probes and showing lines and
variables in the given module.

Currently, this supports only probing on running modules.  Supporting off-line
module probing is the next step.

e.g.)
[show lines]
 # ./perf probe --module drm -L drm_vblank_info
<drm_vblank_info:0>
      0  int drm_vblank_info(struct seq_file *m, void *data)
      1  {
                struct drm_info_node *node = (struct drm_info_node *) m->private
      3         struct drm_device *dev = node->minor->dev;
 ...
[show vars]
 # ./perf probe --module drm -V drm_vblank_info:3
Available variables at drm_vblank_info:3
        @<drm_vblank_info+20>
                (unknown_type)  data
                struct drm_info_node*   node
                struct seq_file*        m
[put a probe]
 # ./perf probe --module drm drm_vblank_info:3 node m
Add new event:
  probe:drm_vblank_info (on drm_vblank_info:3 with node m)

You can now use it on all perf tools, such as:

        perf record -e probe:drm_vblank_info -aR sleep 1
[list probes]
 # ./perf probe -l
probe:drm_vblank_info (on drm_vblank_info:3@drivers/gpu/drm/drm_info.c with ...

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101341.3542.71638.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent fb8c5a56

tools/perf/Documentation/perf-probe.txt

+7 −2
Original line number Diff line number Diff line
@@ -16,9 +16,9 @@ or 
or

'perf probe' --list

or

'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'

'perf probe' [options] --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'

or

'perf probe' [--externs] --vars='PROBEPOINT'

'perf probe' [options] --vars='PROBEPOINT'



DESCRIPTION

-----------
@@ -33,6 +33,11 @@ OPTIONS 
--vmlinux=PATH::

	Specify vmlinux path which has debuginfo (Dwarf binary).



-m::

--module=MODNAME::

	Specify module name in which perf-probe searches probe points

	or lines.



-s::

--source=PATH::

	Specify path to kernel source.

tools/perf/builtin-probe.c

+8 −3
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ static struct { 
	struct perf_probe_event events[MAX_PROBES];

	struct strlist *dellist;

	struct line_range line_range;

	const char *target_module;

	int max_probe_points;

} params;
@@ -162,8 +163,8 @@ static const char * const probe_usage[] = { 
	"perf probe [<options>] --del '[GROUP:]EVENT' ...",

	"perf probe --list",

#ifdef DWARF_SUPPORT

	"perf probe --line 'LINEDESC'",

	"perf probe [--externs] --vars 'PROBEPOINT'",

	"perf probe [<options>] --line 'LINEDESC'",

	"perf probe [<options>] --vars 'PROBEPOINT'",

#endif

	NULL

};
@@ -214,6 +215,8 @@ static const struct option options[] = { 
		   "file", "vmlinux pathname"),

	OPT_STRING('s', "source", &symbol_conf.source_prefix,

		   "directory", "path to kernel source"),

	OPT_STRING('m', "module", &params.target_module,

		   "modname", "target module name"),

#endif

	OPT__DRY_RUN(&probe_event_dry_run),

	OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
@@ -278,7 +281,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
			usage_with_options(probe_usage, options);

		}



		ret = show_line_range(&params.line_range);

		ret = show_line_range(&params.line_range, params.target_module);

		if (ret < 0)

			pr_err("  Error: Failed to show lines. (%d)\n", ret);

		return ret;
@@ -291,6 +294,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
		}

		ret = show_available_vars(params.events, params.nevents,

					  params.max_probe_points,

					  params.target_module,

					  params.show_ext_vars);

		if (ret < 0)

			pr_err("  Error: Failed to show vars. (%d)\n", ret);
@@ -310,6 +314,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used) 
	if (params.nevents) {

		ret = add_perf_probe_events(params.events, params.nevents,

					    params.max_probe_points,

					    params.target_module,

					    params.force_add);

		if (ret < 0) {

			pr_err("  Error: Failed to add events. (%d)\n", ret);

tools/perf/util/map.h

+10 −0
Original line number Diff line number Diff line
@@ -215,6 +215,16 @@ struct symbol *map_groups__find_function_by_name(struct map_groups *self, 
	return map_groups__find_symbol_by_name(self, MAP__FUNCTION, name, mapp, filter);

}



static inline

struct symbol *machine__find_kernel_function_by_name(struct machine *self,

						     const char *name,

						     struct map **mapp,

						     symbol_filter_t filter)

{

	return map_groups__find_function_by_name(&self->kmaps, name, mapp,

						 filter);

}



int map_groups__fixup_overlappings(struct map_groups *self, struct map *map,

				   int verbose, FILE *fp);

tools/perf/util/probe-event.c

+79 −44
Original line number Diff line number Diff line
@@ -74,10 +74,9 @@ static int e_snprintf(char *str, size_t size, const char *format, ...) 
static char *synthesize_perf_probe_point(struct perf_probe_point *pp);

static struct machine machine;



/* Initialize symbol maps and path of vmlinux */

/* Initialize symbol maps and path of vmlinux/modules */

static int init_vmlinux(void)

{

	struct dso *kernel;

	int ret;



	symbol_conf.sort_by_name = true;
@@ -91,33 +90,61 @@ static int init_vmlinux(void) 
		goto out;

	}



	ret = machine__init(&machine, "/", 0);

	ret = machine__init(&machine, "", HOST_KERNEL_ID);

	if (ret < 0)

		goto out;



	kernel = dso__new_kernel(symbol_conf.vmlinux_name);

	if (kernel == NULL)

		die("Failed to create kernel dso.");



	ret = __machine__create_kernel_maps(&machine, kernel);

	if (ret < 0)

		pr_debug("Failed to create kernel maps.\n");



	if (machine__create_kernel_maps(&machine) < 0) {

		pr_debug("machine__create_kernel_maps ");

		goto out;

	}

out:

	if (ret < 0)

		pr_warning("Failed to init vmlinux path.\n");

	return ret;

}



#ifdef DWARF_SUPPORT

static int open_vmlinux(void)

static struct symbol *__find_kernel_function_by_name(const char *name,

						     struct map **mapp)

{

	if (map__load(machine.vmlinux_maps[MAP__FUNCTION], NULL) < 0) {

	return machine__find_kernel_function_by_name(&machine, name, mapp,

						     NULL);

}



const char *kernel_get_module_path(const char *module)

{

	struct dso *dso;



	if (module) {

		list_for_each_entry(dso, &machine.kernel_dsos, node) {

			if (strncmp(dso->short_name + 1, module,

				    dso->short_name_len - 2) == 0)

				goto found;

		}

		pr_debug("Failed to find module %s.\n", module);

		return NULL;

	} else {

		dso = machine.vmlinux_maps[MAP__FUNCTION]->dso;

		if (dso__load_vmlinux_path(dso,

			 machine.vmlinux_maps[MAP__FUNCTION], NULL) < 0) {

			pr_debug("Failed to load kernel map.\n");

		return -EINVAL;

			return NULL;

		}

	pr_debug("Try to open %s\n", machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name);

	return open(machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name, O_RDONLY);

	}

found:

	return dso->long_name;

}



#ifdef DWARF_SUPPORT

static int open_vmlinux(const char *module)

{

	const char *path = kernel_get_module_path(module);

	if (!path) {

		pr_err("Failed to find path of %s module", module ?: "kernel");

		return -ENOENT;

	}

	pr_debug("Try to open %s\n", path);

	return open(path, O_RDONLY);

}



/*
@@ -128,17 +155,16 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp, 
					struct perf_probe_point *pp)

{

	struct symbol *sym;

	int fd, ret = -ENOENT;

	struct map *map;

	u64 addr;

	int ret = -ENOENT;



	sym = map__find_symbol_by_name(machine.vmlinux_maps[MAP__FUNCTION],

				       tp->symbol, NULL);

	sym = __find_kernel_function_by_name(tp->symbol, &map);

	if (sym) {

		fd = open_vmlinux();

		if (fd >= 0) {

			ret = find_perf_probe_point(fd,

						 sym->start + tp->offset, pp);

			close(fd);

		}

		addr = map->unmap_ip(map, sym->start + tp->offset);

		pr_debug("try to find %s+%ld@%llx\n", tp->symbol,

			 tp->offset, addr);

		ret = find_perf_probe_point((unsigned long)addr, pp);

	}

	if (ret <= 0) {

		pr_debug("Failed to find corresponding probes from "
@@ -156,12 +182,12 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp, 
/* Try to find perf_probe_event with debuginfo */

static int try_to_find_probe_trace_events(struct perf_probe_event *pev,

					   struct probe_trace_event **tevs,

					   int max_tevs)

					   int max_tevs, const char *module)

{

	bool need_dwarf = perf_probe_event_need_dwarf(pev);

	int fd, ntevs;



	fd = open_vmlinux();

	fd = open_vmlinux(module);

	if (fd < 0) {

		if (need_dwarf) {

			pr_warning("Failed to open debuginfo file.\n");
@@ -300,7 +326,7 @@ static int show_one_line(FILE *fp, int l, bool skip, bool show_num) 
 * Show line-range always requires debuginfo to find source file and

 * line number.

 */

int show_line_range(struct line_range *lr)

int show_line_range(struct line_range *lr, const char *module)

{

	int l = 1;

	struct line_node *ln;
@@ -313,7 +339,7 @@ int show_line_range(struct line_range *lr) 
	if (ret < 0)

		return ret;



	fd = open_vmlinux();

	fd = open_vmlinux(module);

	if (fd < 0) {

		pr_warning("Failed to open debuginfo file.\n");

		return fd;
@@ -421,7 +447,7 @@ static int show_available_vars_at(int fd, struct perf_probe_event *pev, 


/* Show available variables on given probe point */

int show_available_vars(struct perf_probe_event *pevs, int npevs,

			int max_vls, bool externs)

			int max_vls, const char *module, bool externs)

{

	int i, fd, ret = 0;
@@ -429,7 +455,7 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs, 
	if (ret < 0)

		return ret;



	fd = open_vmlinux();

	fd = open_vmlinux(module);

	if (fd < 0) {

		pr_warning("Failed to open debuginfo file.\n");

		return fd;
@@ -449,6 +475,13 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs, 
static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,

					struct perf_probe_point *pp)

{

	struct symbol *sym;



	sym = __find_kernel_function_by_name(tp->symbol, NULL);

	if (!sym) {

		pr_err("Failed to find symbol %s in kernel.\n", tp->symbol);

		return -ENOENT;

	}

	pp->function = strdup(tp->symbol);

	if (pp->function == NULL)

		return -ENOMEM;
@@ -460,7 +493,7 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp, 


static int try_to_find_probe_trace_events(struct perf_probe_event *pev,

				struct probe_trace_event **tevs __unused,

				int max_tevs __unused)

				int max_tevs __unused, const char *mod __unused)

{

	if (perf_probe_event_need_dwarf(pev)) {

		pr_warning("Debuginfo-analysis is not supported.\n");
@@ -469,14 +502,15 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev, 
	return 0;

}



int show_line_range(struct line_range *lr __unused)

int show_line_range(struct line_range *lr __unused, const char *module __unused)

{

	pr_warning("Debuginfo-analysis is not supported.\n");

	return -ENOSYS;

}



int show_available_vars(struct perf_probe_event *pevs __unused,

			int npevs __unused, int max_probe_points __unused)

			int npevs __unused, int max_vls __unused,

			const char *module __unused, bool externs __unused)

{

	pr_warning("Debuginfo-analysis is not supported.\n");

	return -ENOSYS;
@@ -1588,14 +1622,14 @@ static int __add_probe_trace_events(struct perf_probe_event *pev, 


static int convert_to_probe_trace_events(struct perf_probe_event *pev,

					  struct probe_trace_event **tevs,

					  int max_tevs)

					  int max_tevs, const char *module)

{

	struct symbol *sym;

	int ret = 0, i;

	struct probe_trace_event *tev;



	/* Convert perf_probe_event with debuginfo */

	ret = try_to_find_probe_trace_events(pev, tevs, max_tevs);

	ret = try_to_find_probe_trace_events(pev, tevs, max_tevs, module);

	if (ret != 0)

		return ret;
@@ -1644,8 +1678,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev, 
	}



	/* Currently just checking function name from symbol map */

	sym = map__find_symbol_by_name(machine.vmlinux_maps[MAP__FUNCTION],

				       tev->point.symbol, NULL);

	sym = __find_kernel_function_by_name(tev->point.symbol, NULL);

	if (!sym) {

		pr_warning("Kernel symbol \'%s\' not found.\n",

			   tev->point.symbol);
@@ -1668,7 +1701,7 @@ struct __event_package { 
};



int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,

			  int max_tevs, bool force_add)

			  int max_tevs, const char *module, bool force_add)

{

	int i, j, ret;

	struct __event_package *pkgs;
@@ -1689,7 +1722,9 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs, 
		pkgs[i].pev = &pevs[i];

		/* Convert with or without debuginfo */

		ret  = convert_to_probe_trace_events(pkgs[i].pev,

						      &pkgs[i].tevs, max_tevs);

						     &pkgs[i].tevs,

						     max_tevs,

						     module);

		if (ret < 0)

			goto end;

		pkgs[i].ntevs = ret;

tools/perf/util/probe-event.h

+7 −3
Original line number Diff line number Diff line
@@ -115,14 +115,18 @@ extern void clear_perf_probe_event(struct perf_probe_event *pev); 
/* Command string to line-range */

extern int parse_line_range_desc(const char *cmd, struct line_range *lr);



/* Internal use: Return kernel/module path */

extern const char *kernel_get_module_path(const char *module);



extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,

				 int max_probe_points, bool force_add);

				 int max_probe_points, const char *module,

				 bool force_add);

extern int del_perf_probe_events(struct strlist *dellist);

extern int show_perf_probe_events(void);

extern int show_line_range(struct line_range *lr);

extern int show_line_range(struct line_range *lr, const char *module);

extern int show_available_vars(struct perf_probe_event *pevs, int npevs,

			       int max_probe_points, bool externs);

			       int max_probe_points, const char *module,

			       bool externs);





/* Maximum index number of event-name postfix */