tools lib traceevent: Add pevent_print_func_field() helper function

Add the pevent_print_func_field() that will look up a field that is
expected to be a function pointer, and it will print the function name
and offset of the address given by the field.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20131101215501.869542711@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index fc6f35f591f6..8f450adaa9c2 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -5367,6 +5367,48 @@ int pevent_print_num_field(struct trace_seq *s, const char *fmt,
         return -1;
 }
 
+/**
+ * pevent_print_func_field - print a field and a format for function pointers
+ * @s: The seq to print to
+ * @fmt: The printf format to print the field with.
+ * @event: the event that the field is for
+ * @name: The name of the field
+ * @record: The record with the field name.
+ * @err: print default error if failed.
+ *
+ * Returns: 0 on success, -1 field not found, or 1 if buffer is full.
+ */
+int pevent_print_func_field(struct trace_seq *s, const char *fmt,
+                            struct event_format *event, const char *name,
+                            struct pevent_record *record, int err)
+{
+        struct format_field *field = pevent_find_field(event, name);
+        struct pevent *pevent = event->pevent;
+        unsigned long long val;
+        struct func_map *func;
+        char tmp[128];
+
+        if (!field)
+                goto failed;
+
+        if (pevent_read_number_field(field, record->data, &val))
+                goto failed;
+
+        func = find_func(pevent, val);
+
+        if (func)
+                snprintf(tmp, 128, "%s/0x%llx", func->func, func->addr - val);
+        else
+                sprintf(tmp, "0x%08llx", val);
+
+        return trace_seq_printf(s, fmt, tmp);
+
+ failed:
+        if (err)
+                trace_seq_printf(s, "CAN'T FIND FIELD \"%s\"", name);
+        return -1;
+}
+
 static void free_func_handle(struct pevent_function_handler *func)
 {
         struct pevent_func_params *params;
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index dc8539ee9485..8d73d2594f65 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -569,6 +569,10 @@ int pevent_print_num_field(struct trace_seq *s, const char *fmt,
                            struct event_format *event, const char *name,
                            struct pevent_record *record, int err);
 
+int pevent_print_func_field(struct trace_seq *s, const char *fmt,
+                           struct event_format *event, const char *name,
+                           struct pevent_record *record, int err);
+
 int pevent_register_event_handler(struct pevent *pevent, int id,
                                   const char *sys_name, const char *event_name,
                                   pevent_event_handler_func func, void *context);