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.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 37 insertions, 6 deletions

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 4935c09dd5b5..ee3d84a7c895 100644
--- a/tools/perf/builtin-probe.c
+++ b/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");