perf probe: Add probed module in front of function

Add probed module name and ":" in front of function name
if -m module option is given. In the result, the symbol
name passed to kprobe-tracer becomes MODULE:FUNCTION,
so that kallsyms can solve it as a symbol in the module
correctly.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20110627072745.6528.26416.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

2 files changed, 39 insertions, 9 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 920c1957d6d..ee3f41eec5c 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -226,14 +226,26 @@ static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
         return 0;
 }
 
+static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
+                                            int ntevs, const char *module)
+{
+        int i;
+        for (i = 0; i < ntevs; i++) {
+                tevs[i].point.module = strdup(module);
+                if (!tevs[i].point.module)
+                        return -ENOMEM;
+        }
+        return 0;
+}
+
 /* 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, const char *module)
+                                          struct probe_trace_event **tevs,
+                                          int max_tevs, const char *module)
 {
         bool need_dwarf = perf_probe_event_need_dwarf(pev);
         struct debuginfo *dinfo = open_debuginfo(module);
-        int ntevs;
+        int ntevs, ret = 0;
 
         if (!dinfo) {
                 if (need_dwarf) {
@@ -251,7 +263,10 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
 
         if (ntevs > 0) {        /* Succeeded to find trace events */
                 pr_debug("find %d probe_trace_events.\n", ntevs);
-                return ntevs;
+                if (module)
+                        ret = add_module_to_probe_trace_events(*tevs, ntevs,
+                                                               module);
+                return ret < 0 ? ret : ntevs;
         }
 
         if (ntevs == 0) {       /* No error but failed to find probe point. */
@@ -1010,7 +1025,7 @@ bool perf_probe_event_need_dwarf(struct perf_probe_event *pev)
 
 /* Parse probe_events event into struct probe_point */
 static int parse_probe_trace_command(const char *cmd,
-                                        struct probe_trace_event *tev)
+                                     struct probe_trace_event *tev)
 {
         struct probe_trace_point *tp = &tev->point;
         char pr;
@@ -1043,8 +1058,14 @@ static int parse_probe_trace_command(const char *cmd,
 
         tp->retprobe = (pr == 'r');
 
-        /* Scan function name and offset */
-        ret = sscanf(argv[1], "%a[^+]+%lu", (float *)(void *)&tp->symbol,
+        /* Scan module name(if there), function name and offset */
+        p = strchr(argv[1], ':');
+        if (p) {
+                tp->module = strndup(argv[1], p - argv[1]);
+                p++;
+        } else
+                p = argv[1];
+        ret = sscanf(p, "%a[^+]+%lu", (float *)(void *)&tp->symbol,
                      &tp->offset);
         if (ret == 1)
                 tp->offset = 0;
@@ -1289,9 +1310,10 @@ char *synthesize_probe_trace_command(struct probe_trace_event *tev)
         if (buf == NULL)
                 return NULL;
 
-        len = e_snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s+%lu",
+        len = e_snprintf(buf, MAX_CMDLEN, "%c:%s/%s %s%s%s+%lu",
                          tp->retprobe ? 'r' : 'p',
                          tev->group, tev->event,
+                         tp->module ?: "", tp->module ? ":" : "",
                          tp->symbol, tp->offset);
         if (len <= 0)
                 goto error;
@@ -1398,6 +1420,8 @@ static void clear_probe_trace_event(struct probe_trace_event *tev)
                 free(tev->group);
         if (tev->point.symbol)
                 free(tev->point.symbol);
+        if (tev->point.module)
+                free(tev->point.module);
         for (i = 0; i < tev->nargs; i++) {
                 if (tev->args[i].name)
                         free(tev->args[i].name);
@@ -1749,7 +1773,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
         /* Convert perf_probe_event with debuginfo */
         ret = try_to_find_probe_trace_events(pev, tevs, max_tevs, module);
         if (ret != 0)
-                return ret;
+                return ret;     /* Found in debuginfo or got an error */
 
         /* Allocate trace event buffer */
         tev = *tevs = zalloc(sizeof(struct probe_trace_event));
@@ -1762,6 +1786,11 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
                 ret = -ENOMEM;
                 goto error;
         }
+        tev->point.module = strdup(module);
+        if (tev->point.module == NULL) {
+                ret = -ENOMEM;
+                goto error;
+        }
         tev->point.offset = pev->point.offset;
         tev->point.retprobe = pev->point.retprobe;
         tev->nargs = pev->nargs;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 3434fc9d79d..a7dee835f49 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -10,6 +10,7 @@ extern bool probe_event_dry_run;
 /* kprobe-tracer tracing point */
 struct probe_trace_point {
         char            *symbol;        /* Base symbol */
+        char            *module;        /* Module name */
         unsigned long   offset;         /* Offset from symbol */
         bool            retprobe;       /* Return probe flag */
 };