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Subject[PATCH 19/20] perf probe: Add probed module in front of function
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

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>
---
tools/perf/util/probe-event.c | 47 +++++++++++++++++++++++++++++++++-------
tools/perf/util/probe-event.h | 1 +
2 files changed, 39 insertions(+), 9 deletions(-)
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 920c195..ee3f41e 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 3434fc9..a7dee83 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 */
};
--
1.7.5.4



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