Merge branch 'perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux-2.6 into perf/urgent

8 files changed, 793 insertions, 194 deletions

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 27d52da..62de1b7 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -16,7 +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' [options] --vars='PROBEPOINT'
 
 DESCRIPTION
 -----------
@@ -31,6 +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.
@@ -57,6 +64,15 @@ OPTIONS
 	Show source code lines which can be probed. This needs an argument
 	which specifies a range of the source code. (see LINE SYNTAX for detail)
 
+-V::
+--vars=::
+	Show available local variables at given probe point. The argument
+	syntax is same as PROBE SYNTAX, but NO ARGs.
+
+--externs::
+	(Only for --vars) Show external defined variables in addition to local
+	variables.
+
 -f::
 --force::
 	Forcibly add events with existing name.
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 199d5e1..2e000c0 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -50,14 +50,17 @@ static struct {
 	bool list_events;
 	bool force_add;
 	bool show_lines;
+	bool show_vars;
+	bool show_ext_vars;
+	bool mod_events;
 	int nevents;
 	struct perf_probe_event events[MAX_PROBES];
 	struct strlist *dellist;
 	struct line_range line_range;
+	const char *target_module;
 	int max_probe_points;
 } params;
 
-
 /* Parse an event definition. Note that any error must die. */
 static int parse_probe_event(const char *str)
 {
@@ -92,6 +95,7 @@ static int parse_probe_event_argv(int argc, const char **argv)
 	len = 0;
 	for (i = 0; i < argc; i++)
 		len += sprintf(&buf[len], "%s ", argv[i]);
+	params.mod_events = true;
 	ret = parse_probe_event(buf);
 	free(buf);
 	return ret;
@@ -100,9 +104,10 @@ static int parse_probe_event_argv(int argc, const char **argv)
 static int opt_add_probe_event(const struct option *opt __used,
 			      const char *str, int unset __used)
 {
-	if (str)
+	if (str) {
+		params.mod_events = true;
 		return parse_probe_event(str);
-	else
+	} else
 		return 0;
 }
 
@@ -110,6 +115,7 @@ static int opt_del_probe_event(const struct option *opt __used,
 			       const char *str, int unset __used)
 {
 	if (str) {
+		params.mod_events = true;
 		if (!params.dellist)
 			params.dellist = strlist__new(true, NULL);
 		strlist__add(params.dellist, str);
@@ -130,6 +136,25 @@ static int opt_show_lines(const struct option *opt __used,
 
 	return ret;
 }
+
+static int opt_show_vars(const struct option *opt __used,
+			 const char *str, int unset __used)
+{
+	struct perf_probe_event *pev = &params.events[params.nevents];
+	int ret;
+
+	if (!str)
+		return 0;
+
+	ret = parse_probe_event(str);
+	if (!ret && pev->nargs != 0) {
+		pr_err("  Error: '--vars' doesn't accept arguments.\n");
+		return -EINVAL;
+	}
+	params.show_vars = true;
+
+	return ret;
+}
 #endif
 
 static const char * const probe_usage[] = {
@@ -138,7 +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 [<options>] --line 'LINEDESC'",
+	"perf probe [<options>] --vars 'PROBEPOINT'",
 #endif
 	NULL
 };
@@ -180,10 +206,17 @@ static const struct option options[] = {
 	OPT_CALLBACK('L', "line", NULL,
 		     "FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]",
 		     "Show source code lines.", opt_show_lines),
+	OPT_CALLBACK('V', "vars", NULL,
+		     "FUNC[@SRC][+OFF|%return|:RL|;PT]|SRC:AL|SRC;PT",
+		     "Show accessible variables on PROBEDEF", opt_show_vars),
+	OPT_BOOLEAN('\0', "externs", &params.show_ext_vars,
+		    "Show external variables too (with --vars only)"),
 	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
 		   "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,
@@ -217,7 +250,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 		usage_with_options(probe_usage, options);
 
 	if (params.list_events) {
-		if (params.nevents != 0 || params.dellist) {
+		if (params.mod_events) {
 			pr_err("  Error: Don't use --list with --add/--del.\n");
 			usage_with_options(probe_usage, options);
 		}
@@ -225,6 +258,10 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 			pr_err("  Error: Don't use --list with --line.\n");
 			usage_with_options(probe_usage, options);
 		}
+		if (params.show_vars) {
+			pr_err(" Error: Don't use --list with --vars.\n");
+			usage_with_options(probe_usage, options);
+		}
 		ret = show_perf_probe_events();
 		if (ret < 0)
 			pr_err("  Error: Failed to show event list. (%d)\n",
@@ -234,17 +271,35 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 
 #ifdef DWARF_SUPPORT
 	if (params.show_lines) {
-		if (params.nevents != 0 || params.dellist) {
-			pr_warning("  Error: Don't use --line with"
-				   " --add/--del.\n");
+		if (params.mod_events) {
+			pr_err("  Error: Don't use --line with"
+			       " --add/--del.\n");
+			usage_with_options(probe_usage, options);
+		}
+		if (params.show_vars) {
+			pr_err(" Error: Don't use --line with --vars.\n");
 			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;
 	}
+	if (params.show_vars) {
+		if (params.mod_events) {
+			pr_err("  Error: Don't use --vars with"
+			       " --add/--del.\n");
+			usage_with_options(probe_usage, options);
+		}
+		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);
+		return ret;
+	}
 #endif
 
 	if (params.dellist) {
@@ -258,8 +313,9 @@ 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.force_add,
-					    params.max_probe_points);
+					    params.max_probe_points,
+					    params.target_module,
+					    params.force_add);
 		if (ret < 0) {
 			pr_err("  Error: Failed to add events. (%d)\n", ret);
 			return ret;
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 7857579..b397c03 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -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);
 
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index fcc16e4..3b6a529 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -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;
 }
 
+static struct symbol *__find_kernel_function_by_name(const char *name,
+						     struct map **mapp)
+{
+	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 NULL;
+		}
+	}
+found:
+	return dso->long_name;
+}
+
 #ifdef DWARF_SUPPORT
-static int open_vmlinux(void)
+static int open_vmlinux(const char *module)
 {
-	if (map__load(machine.vmlinux_maps[MAP__FUNCTION], NULL) < 0) {
-		pr_debug("Failed to load kernel map.\n");
-		return -EINVAL;
+	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", machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name);
-	return open(machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
+	pr_debug("Try to open %s\n", path);
+	return open(path, O_RDONLY);
 }
 
 /*
@@ -125,20 +152,19 @@ static int open_vmlinux(void)
  * Currently only handles kprobes.
  */
 static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
-				       struct perf_probe_point *pp)
+					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 @@ error:
  * 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;
@@ -378,11 +404,84 @@ end:
 	return ret;
 }
 
+static int show_available_vars_at(int fd, struct perf_probe_event *pev,
+				  int max_vls, bool externs)
+{
+	char *buf;
+	int ret, i;
+	struct str_node *node;
+	struct variable_list *vls = NULL, *vl;
+
+	buf = synthesize_perf_probe_point(&pev->point);
+	if (!buf)
+		return -EINVAL;
+	pr_debug("Searching variables at %s\n", buf);
+
+	ret = find_available_vars_at(fd, pev, &vls, max_vls, externs);
+	if (ret > 0) {
+		/* Some variables were found */
+		fprintf(stdout, "Available variables at %s\n", buf);
+		for (i = 0; i < ret; i++) {
+			vl = &vls[i];
+			/*
+			 * A probe point might be converted to
+			 * several trace points.
+			 */
+			fprintf(stdout, "\t@<%s+%lu>\n", vl->point.symbol,
+				vl->point.offset);
+			free(vl->point.symbol);
+			if (vl->vars) {
+				strlist__for_each(node, vl->vars)
+					fprintf(stdout, "\t\t%s\n", node->s);
+				strlist__delete(vl->vars);
+			} else
+				fprintf(stdout, "(No variables)\n");
+		}
+		free(vls);
+	} else
+		pr_err("Failed to find variables at %s (%d)\n", buf, ret);
+
+	free(buf);
+	return ret;
+}
+
+/* Show available variables on given probe point */
+int show_available_vars(struct perf_probe_event *pevs, int npevs,
+			int max_vls, const char *module, bool externs)
+{
+	int i, fd, ret = 0;
+
+	ret = init_vmlinux();
+	if (ret < 0)
+		return ret;
+
+	fd = open_vmlinux(module);
+	if (fd < 0) {
+		pr_warning("Failed to open debuginfo file.\n");
+		return fd;
+	}
+
+	setup_pager();
+
+	for (i = 0; i < npevs && ret >= 0; i++)
+		ret = show_available_vars_at(fd, &pevs[i], max_vls, externs);
+
+	close(fd);
+	return ret;
+}
+
 #else	/* !DWARF_SUPPORT */
 
 static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
-				       struct perf_probe_point *pp)
+					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;
@@ -394,7 +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");
@@ -403,12 +502,19 @@ 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_vls __unused,
+			const char *module __unused, bool externs __unused)
+{
+	pr_warning("Debuginfo-analysis is not supported.\n");
+	return -ENOSYS;
+}
 #endif
 
 int parse_line_range_desc(const char *arg, struct line_range *lr)
@@ -1087,7 +1193,7 @@ error:
 }
 
 static int convert_to_perf_probe_event(struct probe_trace_event *tev,
-				struct perf_probe_event *pev)
+				       struct perf_probe_event *pev)
 {
 	char buf[64] = "";
 	int i, ret;
@@ -1516,14 +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;
 
@@ -1572,8 +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);
@@ -1596,7 +1701,7 @@ struct __event_package {
 };
 
 int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
-			  bool force_add, int max_tevs)
+			  int max_tevs, const char *module, bool force_add)
 {
 	int i, j, ret;
 	struct __event_package *pkgs;
@@ -1617,7 +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;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 5af3924..5accbed 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -90,6 +90,12 @@ struct line_range {
 	struct list_head	line_list;	/* Visible lines */
 };
 
+/* List of variables */
+struct variable_list {
+	struct probe_trace_point	point;	/* Actual probepoint */
+	struct strlist			*vars;	/* Available variables */
+};
+
 /* Command string to events */
 extern int parse_perf_probe_command(const char *cmd,
 				    struct perf_probe_event *pev);
@@ -109,12 +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,
-				 bool force_add, int max_probe_points);
+				 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, const char *module,
+			       bool externs);
 
 
 /* Maximum index number of event-name postfix */
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 32b81f7..c20bd52 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -116,6 +116,101 @@ static void line_list__free(struct list_head *head)
 	}
 }
 
+/* Dwarf FL wrappers */
+
+static int __linux_kernel_find_elf(Dwfl_Module *mod,
+				   void **userdata,
+				   const char *module_name,
+				   Dwarf_Addr base,
+				   char **file_name, Elf **elfp)
+{
+	int fd;
+	const char *path = kernel_get_module_path(module_name);
+
+	if (path) {
+		fd = open(path, O_RDONLY);
+		if (fd >= 0) {
+			*file_name = strdup(path);
+			return fd;
+		}
+	}
+	/* If failed, try to call standard method */
+	return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
+					  file_name, elfp);
+}
+
+static char *debuginfo_path;	/* Currently dummy */
+
+static const Dwfl_Callbacks offline_callbacks = {
+	.find_debuginfo = dwfl_standard_find_debuginfo,
+	.debuginfo_path = &debuginfo_path,
+
+	.section_address = dwfl_offline_section_address,
+
+	/* We use this table for core files too.  */
+	.find_elf = dwfl_build_id_find_elf,
+};
+
+static const Dwfl_Callbacks kernel_callbacks = {
+	.find_debuginfo = dwfl_standard_find_debuginfo,
+	.debuginfo_path = &debuginfo_path,
+
+	.find_elf = __linux_kernel_find_elf,
+	.section_address = dwfl_linux_kernel_module_section_address,
+};
+
+/* Get a Dwarf from offline image */
+static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
+{
+	Dwfl_Module *mod;
+	Dwarf *dbg = NULL;
+
+	if (!dwflp)
+		return NULL;
+
+	*dwflp = dwfl_begin(&offline_callbacks);
+	if (!*dwflp)
+		return NULL;
+
+	mod = dwfl_report_offline(*dwflp, "", "", fd);
+	if (!mod)
+		goto error;
+
+	dbg = dwfl_module_getdwarf(mod, bias);
+	if (!dbg) {
+error:
+		dwfl_end(*dwflp);
+		*dwflp = NULL;
+	}
+	return dbg;
+}
+
+/* Get a Dwarf from live kernel image */
+static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
+					  Dwarf_Addr *bias)
+{
+	Dwarf *dbg;
+
+	if (!dwflp)
+		return NULL;
+
+	*dwflp = dwfl_begin(&kernel_callbacks);
+	if (!*dwflp)
+		return NULL;
+
+	/* Load the kernel dwarves: Don't care the result here */
+	dwfl_linux_kernel_report_kernel(*dwflp);
+	dwfl_linux_kernel_report_modules(*dwflp);
+
+	dbg = dwfl_addrdwarf(*dwflp, addr, bias);
+	/* Here, check whether we could get a real dwarf */
+	if (!dbg) {
+		dwfl_end(*dwflp);
+		*dwflp = NULL;
+	}
+	return dbg;
+}
+
 /* Dwarf wrappers */
 
 /* Find the realpath of the target file. */
@@ -160,26 +255,44 @@ static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 	return name ? (strcmp(tname, name) == 0) : false;
 }
 
-/* Get type die, but skip qualifiers and typedef */
-static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
+/* Get type die */
+static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 {
 	Dwarf_Attribute attr;
+
+	if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
+	    dwarf_formref_die(&attr, die_mem))
+		return die_mem;
+	else
+		return NULL;
+}
+
+/* Get a type die, but skip qualifiers */
+static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
+{
 	int tag;
 
 	do {
-		if (dwarf_attr(vr_die, DW_AT_type, &attr) == NULL ||
-		    dwarf_formref_die(&attr, die_mem) == NULL)
-			return NULL;
-
-		tag = dwarf_tag(die_mem);
-		vr_die = die_mem;
+		vr_die = die_get_type(vr_die, die_mem);
+		if (!vr_die)
+			break;
+		tag = dwarf_tag(vr_die);
 	} while (tag == DW_TAG_const_type ||
 		 tag == DW_TAG_restrict_type ||
 		 tag == DW_TAG_volatile_type ||
-		 tag == DW_TAG_shared_type ||
-		 tag == DW_TAG_typedef);
+		 tag == DW_TAG_shared_type);
+
+	return vr_die;
+}
 
-	return die_mem;
+/* Get a type die, but skip qualifiers and typedef */
+static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
+{
+	do {
+		vr_die = __die_get_real_type(vr_die, die_mem);
+	} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
+
+	return vr_die;
 }
 
 static bool die_is_signed_type(Dwarf_Die *tp_die)
@@ -320,25 +433,35 @@ static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 	return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 }
 
+struct __find_variable_param {
+	const char *name;
+	Dwarf_Addr addr;
+};
+
 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 {
-	const char *name = data;
+	struct __find_variable_param *fvp = data;
 	int tag;
 
 	tag = dwarf_tag(die_mem);
 	if ((tag == DW_TAG_formal_parameter ||
 	     tag == DW_TAG_variable) &&
-	    die_compare_name(die_mem, name))
+	    die_compare_name(die_mem, fvp->name))
 		return DIE_FIND_CB_FOUND;
 
-	return DIE_FIND_CB_CONTINUE;
+	if (dwarf_haspc(die_mem, fvp->addr))
+		return DIE_FIND_CB_CONTINUE;
+	else
+		return DIE_FIND_CB_SIBLING;
 }
 
-/* Find a variable called 'name' */
-static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
-				    Dwarf_Die *die_mem)
+/* Find a variable called 'name' at given address */
+static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
+				       Dwarf_Addr addr, Dwarf_Die *die_mem)
 {
-	return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
+	struct __find_variable_param fvp = { .name = name, .addr = addr};
+
+	return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
 			      die_mem);
 }
 
@@ -361,6 +484,60 @@ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
 			      die_mem);
 }
 
+/* Get the name of given variable DIE */
+static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
+{
+	Dwarf_Die type;
+	int tag, ret, ret2;
+	const char *tmp = "";
+
+	if (__die_get_real_type(vr_die, &type) == NULL)
+		return -ENOENT;
+
+	tag = dwarf_tag(&type);
+	if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
+		tmp = "*";
+	else if (tag == DW_TAG_subroutine_type) {
+		/* Function pointer */
+		ret = snprintf(buf, len, "(function_type)");
+		return (ret >= len) ? -E2BIG : ret;
+	} else {
+		if (!dwarf_diename(&type))
+			return -ENOENT;
+		if (tag == DW_TAG_union_type)
+			tmp = "union ";
+		else if (tag == DW_TAG_structure_type)
+			tmp = "struct ";
+		/* Write a base name */
+		ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
+		return (ret >= len) ? -E2BIG : ret;
+	}
+	ret = die_get_typename(&type, buf, len);
+	if (ret > 0) {
+		ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
+		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
+	}
+	return ret;
+}
+
+/* Get the name and type of given variable DIE, stored as "type\tname" */
+static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
+{
+	int ret, ret2;
+
+	ret = die_get_typename(vr_die, buf, len);
+	if (ret < 0) {
+		pr_debug("Failed to get type, make it unknown.\n");
+		ret = snprintf(buf, len, "(unknown_type)");
+	}
+	if (ret > 0) {
+		ret2 = snprintf(buf + ret, len - ret, "\t%s",
+				dwarf_diename(vr_die));
+		ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
+	}
+	return ret;
+}
+
 /*
  * Probe finder related functions
  */
@@ -374,8 +551,13 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 	return ref;
 }
 
-/* Show a location */
-static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
+/*
+ * Convert a location into trace_arg.
+ * If tvar == NULL, this just checks variable can be converted.
+ */
+static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
+				     Dwarf_Op *fb_ops,
+				     struct probe_trace_arg *tvar)
 {
 	Dwarf_Attribute attr;
 	Dwarf_Op *op;
@@ -384,20 +566,23 @@ static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
 	Dwarf_Word offs = 0;
 	bool ref = false;
 	const char *regs;
-	struct probe_trace_arg *tvar = pf->tvar;
 	int ret;
 
+	if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
+		goto static_var;
+
 	/* TODO: handle more than 1 exprs */
 	if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL ||
-	    dwarf_getlocation_addr(&attr, pf->addr, &op, &nops, 1) <= 0 ||
+	    dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 ||
 	    nops == 0) {
 		/* TODO: Support const_value */
-		pr_err("Failed to find the location of %s at this address.\n"
-		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
 		return -ENOENT;
 	}
 
 	if (op->atom == DW_OP_addr) {
+static_var:
+		if (!tvar)
+			return 0;
 		/* Static variables on memory (not stack), make @varname */
 		ret = strlen(dwarf_diename(vr_die));
 		tvar->value = zalloc(ret + 2);
@@ -412,14 +597,11 @@ static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
 
 	/* If this is based on frame buffer, set the offset */
 	if (op->atom == DW_OP_fbreg) {
-		if (pf->fb_ops == NULL) {
-			pr_warning("The attribute of frame base is not "
-				   "supported.\n");
+		if (fb_ops == NULL)
 			return -ENOTSUP;
-		}
 		ref = true;
 		offs = op->number;
-		op = &pf->fb_ops[0];
+		op = &fb_ops[0];
 	}
 
 	if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
@@ -435,13 +617,18 @@ static int convert_variable_location(Dwarf_Die *vr_die, struct probe_finder *pf)
 	} else if (op->atom == DW_OP_regx) {
 		regn = op->number;
 	} else {
-		pr_warning("DW_OP %x is not supported.\n", op->atom);
+		pr_debug("DW_OP %x is not supported.\n", op->atom);
 		return -ENOTSUP;
 	}
 
+	if (!tvar)
+		return 0;
+
 	regs = get_arch_regstr(regn);
 	if (!regs) {
-		pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
+		/* This should be a bug in DWARF or this tool */
+		pr_warning("Mapping for DWARF register number %u "
+			   "missing on this architecture.", regn);
 		return -ERANGE;
 	}
 
@@ -666,8 +853,14 @@ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 	pr_debug("Converting variable %s into trace event.\n",
 		 dwarf_diename(vr_die));
 
-	ret = convert_variable_location(vr_die, pf);
-	if (ret == 0 && pf->pvar->field) {
+	ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
+					pf->tvar);
+	if (ret == -ENOENT)
+		pr_err("Failed to find the location of %s at this address.\n"
+		       " Perhaps, it has been optimized out.\n", pf->pvar->var);
+	else if (ret == -ENOTSUP)
+		pr_err("Sorry, we don't support this variable location yet.\n");
+	else if (pf->pvar->field) {
 		ret = convert_variable_fields(vr_die, pf->pvar->var,
 					      pf->pvar->field, &pf->tvar->ref,
 					      &die_mem);
@@ -722,56 +915,39 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */
-	if (die_find_variable(sp_die, pf->pvar->var, &vr_die))
+	if (die_find_variable_at(sp_die, pf->pvar->var, pf->addr, &vr_die))
 		ret = convert_variable(&vr_die, pf);
 	else {
 		/* Search upper class */
 		nscopes = dwarf_getscopes_die(sp_die, &scopes);
-		if (nscopes > 0) {
-			ret = dwarf_getscopevar(scopes, nscopes, pf->pvar->var,
-						0, NULL, 0, 0, &vr_die);
-			if (ret >= 0)
+		while (nscopes-- > 1) {
+			pr_debug("Searching variables in %s\n",
+				 dwarf_diename(&scopes[nscopes]));
+			/* We should check this scope, so give dummy address */
+			if (die_find_variable_at(&scopes[nscopes],
+						 pf->pvar->var, 0,
+						 &vr_die)) {
 				ret = convert_variable(&vr_die, pf);
-			else
-				ret = -ENOENT;
+				goto found;
+			}
+		}
+		if (scopes)
 			free(scopes);
-		} else
-			ret = -ENOENT;
+		ret = -ENOENT;
 	}
+found:
 	if (ret < 0)
 		pr_warning("Failed to find '%s' in this function.\n",
 			   pf->pvar->var);
 	return ret;
 }
 
-/* Show a probe point to output buffer */
-static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
+/* Convert subprogram DIE to trace point */
+static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr,
+				  bool retprobe, struct probe_trace_point *tp)
 {
-	struct probe_trace_event *tev;
 	Dwarf_Addr eaddr;
-	Dwarf_Die die_mem;
 	const char *name;
-	int ret, i;
-	Dwarf_Attribute fb_attr;
-	size_t nops;
-
-	if (pf->ntevs == pf->max_tevs) {
-		pr_warning("Too many( > %d) probe point found.\n",
-			   pf->max_tevs);
-		return -ERANGE;
-	}
-	tev = &pf->tevs[pf->ntevs++];
-
-	/* If no real subprogram, find a real one */
-	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
-		sp_die = die_find_real_subprogram(&pf->cu_die,
-						 pf->addr, &die_mem);
-		if (!sp_die) {
-			pr_warning("Failed to find probe point in any "
-				   "functions.\n");
-			return -ENOENT;
-		}
-	}
 
 	/* Copy the name of probe point */
 	name = dwarf_diename(sp_die);
@@ -781,26 +957,45 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 				   dwarf_diename(sp_die));
 			return -ENOENT;
 		}
-		tev->point.symbol = strdup(name);
-		if (tev->point.symbol == NULL)
+		tp->symbol = strdup(name);
+		if (tp->symbol == NULL)
 			return -ENOMEM;
-		tev->point.offset = (unsigned long)(pf->addr - eaddr);
+		tp->offset = (unsigned long)(paddr - eaddr);
 	} else
 		/* This function has no name. */
-		tev->point.offset = (unsigned long)pf->addr;
+		tp->offset = (unsigned long)paddr;
 
 	/* Return probe must be on the head of a subprogram */
-	if (pf->pev->point.retprobe) {
-		if (tev->point.offset != 0) {
+	if (retprobe) {
+		if (eaddr != paddr) {
 			pr_warning("Return probe must be on the head of"
 				   " a real function\n");
 			return -EINVAL;
 		}
-		tev->point.retprobe = true;
+		tp->retprobe = true;
 	}
 
-	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
-		 tev->point.offset);
+	return 0;
+}
+
+/* Call probe_finder callback with real subprogram DIE */
+static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf)
+{
+	Dwarf_Die die_mem;
+	Dwarf_Attribute fb_attr;
+	size_t nops;
+	int ret;
+
+	/* If no real subprogram, find a real one */
+	if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
+		sp_die = die_find_real_subprogram(&pf->cu_die,
+						  pf->addr, &die_mem);
+		if (!sp_die) {
+			pr_warning("Failed to find probe point in any "
+				   "functions.\n");
+			return -ENOENT;
+		}
+	}
 
 	/* Get the frame base attribute/ops */
 	dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
@@ -820,22 +1015,13 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 #endif
 	}
 
-	/* Find each argument */
-	tev->nargs = pf->pev->nargs;
-	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
-	if (tev->args == NULL)
-		return -ENOMEM;
-	for (i = 0; i < pf->pev->nargs; i++) {
-		pf->pvar = &pf->pev->args[i];
-		pf->tvar = &tev->args[i];
-		ret = find_variable(sp_die, pf);
-		if (ret != 0)
-			return ret;
-	}
+	/* Call finder's callback handler */
+	ret = pf->callback(sp_die, pf);
 
 	/* *pf->fb_ops will be cached in libdw. Don't free it. */
 	pf->fb_ops = NULL;
-	return 0;
+
+	return ret;
 }
 
 /* Find probe point from its line number */
@@ -871,7 +1057,7 @@ static int find_probe_point_by_line(struct probe_finder *pf)
 			 (int)i, lineno, (uintmax_t)addr);
 		pf->addr = addr;
 
-		ret = convert_probe_point(NULL, pf);
+		ret = call_probe_finder(NULL, pf);
 		/* Continuing, because target line might be inlined. */
 	}
 	return ret;
@@ -984,7 +1170,7 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 			 (int)i, lineno, (unsigned long long)addr);
 		pf->addr = addr;
 
-		ret = convert_probe_point(sp_die, pf);
+		ret = call_probe_finder(sp_die, pf);
 		/* Continuing, because target line might be inlined. */
 	}
 	/* TODO: deallocate lines, but how? */
@@ -1019,7 +1205,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 		pr_debug("found inline addr: 0x%jx\n",
 			 (uintmax_t)pf->addr);
 
-		param->retval = convert_probe_point(in_die, pf);
+		param->retval = call_probe_finder(in_die, pf);
 		if (param->retval < 0)
 			return DWARF_CB_ABORT;
 	}
@@ -1057,7 +1243,7 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 			}
 			pf->addr += pp->offset;
 			/* TODO: Check the address in this function */
-			param->retval = convert_probe_point(sp_die, pf);
+			param->retval = call_probe_finder(sp_die, pf);
 		}
 	} else {
 		struct dwarf_callback_param _param = {.data = (void *)pf,
@@ -1079,90 +1265,276 @@ static int find_probe_point_by_func(struct probe_finder *pf)
 	return _param.retval;
 }
 
-/* Find probe_trace_events specified by perf_probe_event from debuginfo */
-int find_probe_trace_events(int fd, struct perf_probe_event *pev,
-			     struct probe_trace_event **tevs, int max_tevs)
+/* Find probe points from debuginfo */
+static int find_probes(int fd, struct probe_finder *pf)
 {
-	struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
-	struct perf_probe_point *pp = &pev->point;
+	struct perf_probe_point *pp = &pf->pev->point;
 	Dwarf_Off off, noff;
 	size_t cuhl;
 	Dwarf_Die *diep;
-	Dwarf *dbg;
+	Dwarf *dbg = NULL;
+	Dwfl *dwfl;
+	Dwarf_Addr bias;	/* Currently ignored */
 	int ret = 0;
 
-	pf.tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
-	if (pf.tevs == NULL)
-		return -ENOMEM;
-	*tevs = pf.tevs;
-	pf.ntevs = 0;
-
-	dbg = dwarf_begin(fd, DWARF_C_READ);
+	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
 	if (!dbg) {
 		pr_warning("No dwarf info found in the vmlinux - "
 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
-		free(pf.tevs);
-		*tevs = NULL;
 		return -EBADF;
 	}
 
 #if _ELFUTILS_PREREQ(0, 142)
 	/* Get the call frame information from this dwarf */
-	pf.cfi = dwarf_getcfi(dbg);
+	pf->cfi = dwarf_getcfi(dbg);
 #endif
 
 	off = 0;
-	line_list__init(&pf.lcache);
+	line_list__init(&pf->lcache);
 	/* Loop on CUs (Compilation Unit) */
 	while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
 	       ret >= 0) {
 		/* Get the DIE(Debugging Information Entry) of this CU */
-		diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
+		diep = dwarf_offdie(dbg, off + cuhl, &pf->cu_die);
 		if (!diep)
 			continue;
 
 		/* Check if target file is included. */
 		if (pp->file)
-			pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
+			pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
 		else
-			pf.fname = NULL;
+			pf->fname = NULL;
 
-		if (!pp->file || pf.fname) {
+		if (!pp->file || pf->fname) {
 			if (pp->function)
-				ret = find_probe_point_by_func(&pf);
+				ret = find_probe_point_by_func(pf);
 			else if (pp->lazy_line)
-				ret = find_probe_point_lazy(NULL, &pf);
+				ret = find_probe_point_lazy(NULL, pf);
 			else {
-				pf.lno = pp->line;
-				ret = find_probe_point_by_line(&pf);
+				pf->lno = pp->line;
+				ret = find_probe_point_by_line(pf);
 			}
 		}
 		off = noff;
 	}
-	line_list__free(&pf.lcache);
-	dwarf_end(dbg);
+	line_list__free(&pf->lcache);
+	if (dwfl)
+		dwfl_end(dwfl);
 
-	return (ret < 0) ? ret : pf.ntevs;
+	return ret;
+}
+
+/* Add a found probe point into trace event list */
+static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf)
+{
+	struct trace_event_finder *tf =
+			container_of(pf, struct trace_event_finder, pf);
+	struct probe_trace_event *tev;
+	int ret, i;
+
+	/* Check number of tevs */
+	if (tf->ntevs == tf->max_tevs) {
+		pr_warning("Too many( > %d) probe point found.\n",
+			   tf->max_tevs);
+		return -ERANGE;
+	}
+	tev = &tf->tevs[tf->ntevs++];
+
+	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
+				     &tev->point);
+	if (ret < 0)
+		return ret;
+
+	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
+		 tev->point.offset);
+
+	/* Find each argument */
+	tev->nargs = pf->pev->nargs;
+	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
+	if (tev->args == NULL)
+		return -ENOMEM;
+	for (i = 0; i < pf->pev->nargs; i++) {
+		pf->pvar = &pf->pev->args[i];
+		pf->tvar = &tev->args[i];
+		ret = find_variable(sp_die, pf);
+		if (ret != 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/* Find probe_trace_events specified by perf_probe_event from debuginfo */
+int find_probe_trace_events(int fd, struct perf_probe_event *pev,
+			    struct probe_trace_event **tevs, int max_tevs)
+{
+	struct trace_event_finder tf = {
+			.pf = {.pev = pev, .callback = add_probe_trace_event},
+			.max_tevs = max_tevs};
+	int ret;
+
+	/* Allocate result tevs array */
+	*tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
+	if (*tevs == NULL)
+		return -ENOMEM;
+
+	tf.tevs = *tevs;
+	tf.ntevs = 0;
+
+	ret = find_probes(fd, &tf.pf);
+	if (ret < 0) {
+		free(*tevs);
+		*tevs = NULL;
+		return ret;
+	}
+
+	return (ret < 0) ? ret : tf.ntevs;
+}
+
+#define MAX_VAR_LEN 64
+
+/* Collect available variables in this scope */
+static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
+{
+	struct available_var_finder *af = data;
+	struct variable_list *vl;
+	char buf[MAX_VAR_LEN];
+	int tag, ret;
+
+	vl = &af->vls[af->nvls - 1];
+
+	tag = dwarf_tag(die_mem);
+	if (tag == DW_TAG_formal_parameter ||
+	    tag == DW_TAG_variable) {
+		ret = convert_variable_location(die_mem, af->pf.addr,
+						af->pf.fb_ops, NULL);
+		if (ret == 0) {
+			ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
+			pr_debug2("Add new var: %s\n", buf);
+			if (ret > 0)
+				strlist__add(vl->vars, buf);
+		}
+	}
+
+	if (af->child && dwarf_haspc(die_mem, af->pf.addr))
+		return DIE_FIND_CB_CONTINUE;
+	else
+		return DIE_FIND_CB_SIBLING;
+}
+
+/* Add a found vars into available variables list */
+static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf)
+{
+	struct available_var_finder *af =
+			container_of(pf, struct available_var_finder, pf);
+	struct variable_list *vl;
+	Dwarf_Die die_mem, *scopes = NULL;
+	int ret, nscopes;
+
+	/* Check number of tevs */
+	if (af->nvls == af->max_vls) {
+		pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
+		return -ERANGE;
+	}
+	vl = &af->vls[af->nvls++];
+
+	ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe,
+				     &vl->point);
+	if (ret < 0)
+		return ret;
+
+	pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
+		 vl->point.offset);
+
+	/* Find local variables */
+	vl->vars = strlist__new(true, NULL);
+	if (vl->vars == NULL)
+		return -ENOMEM;
+	af->child = true;
+	die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem);
+
+	/* Find external variables */
+	if (!af->externs)
+		goto out;
+	/* Don't need to search child DIE for externs. */
+	af->child = false;
+	nscopes = dwarf_getscopes_die(sp_die, &scopes);
+	while (nscopes-- > 1)
+		die_find_child(&scopes[nscopes], collect_variables_cb,
+			       (void *)af, &die_mem);
+	if (scopes)
+		free(scopes);
+
+out:
+	if (strlist__empty(vl->vars)) {
+		strlist__delete(vl->vars);
+		vl->vars = NULL;
+	}
+
+	return ret;
+}
+
+/* Find available variables at given probe point */
+int find_available_vars_at(int fd, struct perf_probe_event *pev,
+			   struct variable_list **vls, int max_vls,
+			   bool externs)
+{
+	struct available_var_finder af = {
+			.pf = {.pev = pev, .callback = add_available_vars},
+			.max_vls = max_vls, .externs = externs};
+	int ret;
+
+	/* Allocate result vls array */
+	*vls = zalloc(sizeof(struct variable_list) * max_vls);
+	if (*vls == NULL)
+		return -ENOMEM;
+
+	af.vls = *vls;
+	af.nvls = 0;
+
+	ret = find_probes(fd, &af.pf);
+	if (ret < 0) {
+		/* Free vlist for error */
+		while (af.nvls--) {
+			if (af.vls[af.nvls].point.symbol)
+				free(af.vls[af.nvls].point.symbol);
+			if (af.vls[af.nvls].vars)
+				strlist__delete(af.vls[af.nvls].vars);
+		}
+		free(af.vls);
+		*vls = NULL;
+		return ret;
+	}
+
+	return (ret < 0) ? ret : af.nvls;
 }
 
 /* Reverse search */
-int find_perf_probe_point(int fd, unsigned long addr,
-			  struct perf_probe_point *ppt)
+int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
 {
 	Dwarf_Die cudie, spdie, indie;
-	Dwarf *dbg;
+	Dwarf *dbg = NULL;
+	Dwfl *dwfl = NULL;
 	Dwarf_Line *line;
-	Dwarf_Addr laddr, eaddr;
+	Dwarf_Addr laddr, eaddr, bias = 0;
 	const char *tmp;
 	int lineno, ret = 0;
 	bool found = false;
 
-	dbg = dwarf_begin(fd, DWARF_C_READ);
-	if (!dbg)
-		return -EBADF;
+	/* Open the live linux kernel */
+	dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
+	if (!dbg) {
+		pr_warning("No dwarf info found in the vmlinux - "
+			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
+		ret = -EINVAL;
+		goto end;
+	}
 
+	/* Adjust address with bias */
+	addr += bias;
 	/* Find cu die */
-	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
+	if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
+		pr_warning("No CU DIE is found at %lx\n", addr);
 		ret = -EINVAL;
 		goto end;
 	}
@@ -1225,7 +1597,8 @@ found:
 	}
 
 end:
-	dwarf_end(dbg);
+	if (dwfl)
+		dwfl_end(dwfl);
 	if (ret >= 0)
 		ret = found ? 1 : 0;
 	return ret;
@@ -1358,6 +1731,8 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
 	struct line_finder *lf = param->data;
 	struct line_range *lr = lf->lr;
 
+	pr_debug("find (%lx) %s\n", dwarf_dieoffset(sp_die),
+		 dwarf_diename(sp_die));
 	if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
 	    die_compare_name(sp_die, lr->function)) {
 		lf->fname = dwarf_decl_file(sp_die);
@@ -1401,10 +1776,12 @@ int find_line_range(int fd, struct line_range *lr)
 	Dwarf_Off off = 0, noff;
 	size_t cuhl;
 	Dwarf_Die *diep;
-	Dwarf *dbg;
+	Dwarf *dbg = NULL;
+	Dwfl *dwfl;
+	Dwarf_Addr bias;	/* Currently ignored */
 	const char *comp_dir;
 
-	dbg = dwarf_begin(fd, DWARF_C_READ);
+	dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
 	if (!dbg) {
 		pr_warning("No dwarf info found in the vmlinux - "
 			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
@@ -1450,8 +1827,7 @@ int find_line_range(int fd, struct line_range *lr)
 	}
 
 	pr_debug("path: %s\n", lr->path);
-	dwarf_end(dbg);
-
+	dwfl_end(dwfl);
 	return (ret < 0) ? ret : lf.found;
 }
 
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 4507d51..bba69d4 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -22,20 +22,27 @@ extern int find_probe_trace_events(int fd, struct perf_probe_event *pev,
 				    int max_tevs);
 
 /* Find a perf_probe_point from debuginfo */
-extern int find_perf_probe_point(int fd, unsigned long addr,
+extern int find_perf_probe_point(unsigned long addr,
 				 struct perf_probe_point *ppt);
 
+/* Find a line range */
 extern int find_line_range(int fd, struct line_range *lr);
 
+/* Find available variables */
+extern int find_available_vars_at(int fd, struct perf_probe_event *pev,
+				  struct variable_list **vls, int max_points,
+				  bool externs);
+
 #include <dwarf.h>
 #include <libdw.h>
+#include <libdwfl.h>
 #include <version.h>
 
 struct probe_finder {
 	struct perf_probe_event	*pev;		/* Target probe event */
-	struct probe_trace_event *tevs;		/* Result trace events */
-	int			ntevs;		/* Number of trace events */
-	int			max_tevs;	/* Max number of trace events */
+
+	/* Callback when a probe point is found */
+	int (*callback)(Dwarf_Die *sp_die, struct probe_finder *pf);
 
 	/* For function searching */
 	int			lno;		/* Line number */
@@ -53,6 +60,22 @@ struct probe_finder {
 	struct probe_trace_arg	*tvar;		/* Current result variable */
 };
 
+struct trace_event_finder {
+	struct probe_finder	pf;
+	struct probe_trace_event *tevs;		/* Found trace events */
+	int			ntevs;		/* Number of trace events */
+	int			max_tevs;	/* Max number of trace events */
+};
+
+struct available_var_finder {
+	struct probe_finder	pf;
+	struct variable_list	*vls;		/* Found variable lists */
+	int			nvls;		/* Number of variable lists */
+	int			max_vls;	/* Max no. of variable lists */
+	bool			externs;	/* Find external vars too */
+	bool			child;		/* Search child scopes */
+};
+
 struct line_finder {
 	struct line_range	*lr;		/* Target line range */
 
diff --git a/tools/perf/util/ui/browser.c b/tools/perf/util/ui/browser.c
index 6d0df80..8bc010e 100644
--- a/tools/perf/util/ui/browser.c
+++ b/tools/perf/util/ui/browser.c
@@ -1,4 +1,3 @@
-#include <slang.h>
 #include "libslang.h"
 #include <linux/compiler.h>
 #include <linux/list.h>