[PATCH 3/6] perf probe: Add supported type casting of running kernel

Masami Hiramatsu
2016-08-18T09:01:01Z

Add a checking routine what types are supported by the
running kernel by finding the pattern in
<debugfs>/tracing/README.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
tools/perf/util/probe-file.c | 57 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/probe-file.h | 10 +++++++
tools/perf/util/probe-finder.c | 1 +
3 files changed, 68 insertions(+)

diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 9aed9c3..552e56b 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -855,3 +855,60 @@ int probe_cache__show_all_caches(struct strfilter *filter)

return 0;
}
+
+static struct {
+ const char *pattern;
+ bool avail;
+ bool checked;
+} probe_type_table[] = {
+#define DEFINE_TYPE(idx, pat, def_avail) \
+ [idx] = {.pattern = pat, .avail = (def_avail)}
+ DEFINE_TYPE(PROBE_TYPE_U, "* u8/16/32/64,*", true),
+ DEFINE_TYPE(PROBE_TYPE_S, "* s8/16/32/64,*", true),
+ DEFINE_TYPE(PROBE_TYPE_X, "* x8/16/32/64,*", false),
+ DEFINE_TYPE(PROBE_TYPE_STRING, "* string,*", true),
+ DEFINE_TYPE(PROBE_TYPE_BITFIELD,
+ "* b<bit-width>@<bit-offset>/<container-size>", true),
+};
+
+bool probe_type_is_available(enum probe_type type)
+{
+ FILE *fp;
+ char *buf = NULL;
+ size_t len = 0;
+ bool target_line = false;
+ bool ret = probe_type_table[type].avail;
+
+ if (type < 0 || type >= PROBE_TYPE_END)
+ return false;
+ /* We don't have to check the type which supported by default */
+ if (ret || probe_type_table[type].checked)
+ return ret;
+
+ if (asprintf(&buf, "%s/README", tracing_path) < 0)
+ return ret;
+
+ fp = fopen(buf, "r");
+ if (!fp)
+ goto end;
+
+ zfree(&buf);
+ while (getline(&buf, &len, fp) > 0 && !ret) {
+ if (!target_line) {
+ target_line = !!strstr(buf, " type: ");
+ if (!target_line)
+ continue;
+ } else if (strstr(buf, "\t ") != buf)
+ break;
+ ret = strglobmatch(buf, probe_type_table[type].pattern);
+ }
+ /* Cache the result */
+ probe_type_table[type].checked = true;
+ probe_type_table[type].avail = ret;
+
+ fclose(fp);
+end:
+ free(buf);
+
+ return ret;
+}
diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
index 9577b5c..eba44c3 100644
--- a/tools/perf/util/probe-file.h
+++ b/tools/perf/util/probe-file.h
@@ -19,6 +19,15 @@ struct probe_cache {
struct list_head entries;
};

+enum probe_type {
+ PROBE_TYPE_U = 0,
+ PROBE_TYPE_S,
+ PROBE_TYPE_X,
+ PROBE_TYPE_STRING,
+ PROBE_TYPE_BITFIELD,
+ PROBE_TYPE_END,
+};
+
#define PF_FL_UPROBE 1
#define PF_FL_RW 2
#define for_each_probe_cache_entry(entry, pcache) \
@@ -54,6 +63,7 @@ struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
const char *group, const char *event);
int probe_cache__show_all_caches(struct strfilter *filter);
+bool probe_type_is_available(enum probe_type type);
#else /* ! HAVE_LIBELF_SUPPORT */
static inline struct probe_cache *probe_cache__new(const char *tgt __maybe_unused)
{
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5c290c6..24dbe23 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -39,6 +39,7 @@
#include "util.h"
#include "symbol.h"
#include "probe-finder.h"
+#include "probe-file.h"

/* Kprobe tracer basic type is up to u64 */
#define MAX_BASIC_TYPE_BITS 64