perf probe: Provide perf interface for uprobes

- Enhances perf to probe user space executables and libraries.
- Enhances -F/--funcs option of "perf probe" to list possible probe points in
  an executable file or library.
- Documents userspace probing support in perf.

[ Probing a function in the executable using function name  ]
perf probe -x /bin/zsh zfree

[ Probing a library function using function name ]
perf probe -x /lib64/libc.so.6 malloc

[ list probe-able functions in an executable ]
perf probe -F -x /bin/zsh

[ list probe-able functions in an library]
perf probe -F -x /lib/libc.so.6
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20120416120909.30661.99781.sendpatchset@srdronam.in.ibm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-probe.txt

@@ -77,7 +77,8 @@ OPTIONS
 
 -F::
 --funcs::
-	Show available functions in given module or kernel.
+	Show available functions in given module or kernel. With -x/--exec,
+	can also list functions in a user space executable / shared library.
 
 --filter=FILTER::
 	(Only for --vars and --funcs) Set filter. FILTER is a combination of glob
@@ -98,6 +99,11 @@ OPTIONS
 --max-probes::
 	Set the maximum number of probe points for an event. Default is 128.
 
+-x::
+--exec=PATH::
+	Specify path to the executable or shared library file for user
+	space tracing. Can also be used with --funcs option.
+
 PROBE SYNTAX
 ------------
 Probe points are defined by following syntax.
@@ -182,6 +188,13 @@ Delete all probes on schedule().
 
  ./perf probe --del='schedule*'
 
+Add probes at zfree() function on /bin/zsh
+
+ ./perf probe -x /bin/zsh zfree
+
+Add probes at malloc() function on libc
+
+ ./perf probe -x /lib/libc.so.6 malloc
 
 SEE ALSO
 --------

tools/perf/builtin-probe.c

@@ -54,6 +54,7 @@ static struct {
 	bool show_ext_vars;
 	bool show_funcs;
 	bool mod_events;
+	bool uprobes;
 	int nevents;
 	struct perf_probe_event events[MAX_PROBES];
 	struct strlist *dellist;
@@ -75,6 +76,8 @@ static int parse_probe_event(const char *str)
 		return -1;
 	}
 
+	pev->uprobes = params.uprobes;
+
 	/* Parse a perf-probe command into event */
 	ret = parse_perf_probe_command(str, pev);
 	pr_debug("%d arguments\n", pev->nargs);
@@ -125,6 +128,28 @@ static int opt_del_probe_event(const struct option *opt __used,
 	return 0;
 }
 
+static int opt_set_target(const struct option *opt, const char *str,
+			int unset __used)
+{
+	int ret = -ENOENT;
+
+	if  (str && !params.target) {
+		if (!strcmp(opt->long_name, "exec"))
+			params.uprobes = true;
+#ifdef DWARF_SUPPORT
+		else if (!strcmp(opt->long_name, "module"))
+			params.uprobes = false;
+#endif
+		else
+			return ret;
+
+		params.target = str;
+		ret = 0;
+	}
+
+	return ret;
+}
+
 #ifdef DWARF_SUPPORT
 static int opt_show_lines(const struct option *opt __used,
 			  const char *str, int unset __used)
@@ -246,9 +271,9 @@ 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,
-		   "modname|path",
-		   "target module name (for online) or path (for offline)"),
+	OPT_CALLBACK('m', "module", NULL, "modname|path",
+		"target module name (for online) or path (for offline)",
+		opt_set_target),
 #endif
 	OPT__DRY_RUN(&probe_event_dry_run),
 	OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
@@ -260,6 +285,8 @@ static const struct option options[] = {
 		     "\t\t\t(default: \"" DEFAULT_VAR_FILTER "\" for --vars,\n"
 		     "\t\t\t \"" DEFAULT_FUNC_FILTER "\" for --funcs)",
 		     opt_set_filter),
+	OPT_CALLBACK('x', "exec", NULL, "executable|path",
+			"target executable name or path", opt_set_target),
 	OPT_END()
 };
 
@@ -310,6 +337,10 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 			pr_err("  Error: Don't use --list with --funcs.\n");
 			usage_with_options(probe_usage, options);
 		}
+		if (params.uprobes) {
+			pr_warning("  Error: Don't use --list with --exec.\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",
@@ -333,8 +364,8 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 		if (!params.filter)
 			params.filter = strfilter__new(DEFAULT_FUNC_FILTER,
 						       NULL);
-		ret = show_available_funcs(params.target,
-					   params.filter);
+		ret = show_available_funcs(params.target, params.filter,
+					params.uprobes);
 		strfilter__delete(params.filter);
 		if (ret < 0)
 			pr_err("  Error: Failed to show functions."
@@ -343,7 +374,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 	}
 
 #ifdef DWARF_SUPPORT
-	if (params.show_lines) {
+	if (params.show_lines && !params.uprobes) {
 		if (params.mod_events) {
 			pr_err("  Error: Don't use --line with"
 			       " --add/--del.\n");

tools/perf/util/probe-event.h

@@ -7,7 +7,7 @@
 
 extern bool probe_event_dry_run;
 
-/* kprobe-tracer tracing point */
+/* kprobe-tracer and uprobe-tracer tracing point */
 struct probe_trace_point {
 	char		*symbol;	/* Base symbol */
 	char		*module;	/* Module name */
@@ -21,7 +21,7 @@ struct probe_trace_arg_ref {
 	long				offset;	/* Offset value */
 };
 
-/* kprobe-tracer tracing argument */
+/* kprobe-tracer and uprobe-tracer tracing argument */
 struct probe_trace_arg {
 	char				*name;	/* Argument name */
 	char				*value;	/* Base value */
@@ -29,12 +29,13 @@ struct probe_trace_arg {
 	struct probe_trace_arg_ref	*ref;	/* Referencing offset */
 };
 
-/* kprobe-tracer tracing event (point + arg) */
+/* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
 struct probe_trace_event {
 	char				*event;	/* Event name */
 	char				*group;	/* Group name */
 	struct probe_trace_point	point;	/* Trace point */
 	int				nargs;	/* Number of args */
+	bool				uprobes;	/* uprobes only */
 	struct probe_trace_arg		*args;	/* Arguments */
 };
 
@@ -70,6 +71,7 @@ struct perf_probe_event {
 	char			*group;	/* Group name */
 	struct perf_probe_point	point;	/* Probe point */
 	int			nargs;	/* Number of arguments */
+	bool			uprobes;
 	struct perf_probe_arg	*args;	/* Arguments */
 };
 
@@ -129,8 +131,8 @@ 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,
 			       struct strfilter *filter, bool externs);
-extern int show_available_funcs(const char *module, struct strfilter *filter);
-
+extern int show_available_funcs(const char *module, struct strfilter *filter,
+				bool user);
 
 /* Maximum index number of event-name postfix */
 #define MAX_EVENT_INDEX	1024

tools/perf/util/symbol.c

@@ -2784,3 +2784,11 @@ int machine__load_vmlinux_path(struct machine *machine, enum map_type type,
 
 	return ret;
 }
+
+struct map *dso__new_map(const char *name)
+{
+	struct dso *dso = dso__new(name);
+	struct map *map = map__new2(0, dso, MAP__FUNCTION);
+
+	return map;
+}

tools/perf/util/symbol.h

@@ -242,6 +242,7 @@ void dso__set_long_name(struct dso *dso, char *name);
 void dso__set_build_id(struct dso *dso, void *build_id);
 void dso__read_running_kernel_build_id(struct dso *dso,
 				       struct machine *machine);
+struct map *dso__new_map(const char *name);
 struct symbol *dso__find_symbol(struct dso *dso, enum map_type type,
 				u64 addr);
 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,