tools lib traceevent: Move kernel_stack event handler to "function" plugin.

The "kernel_stack" event handler does not depend on any trace-cmd
context, it can be used aside from the application. The code is moved to
libtraceevent "function" plugin.

Link: http://lore.kernel.org/linux-trace-devel/20190726124308.18735-2-tz.stoyanov@gmail.com
Link: http://lore.kernel.org/linux-trace-devel/20200702174950.123454-4-tz.stoyanov@gmail.com
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200702185705.284789930@goodmis.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/traceevent/plugins/plugin_function.c b/tools/lib/traceevent/plugins/plugin_function.c
index cafddd6..c7d3219 100644 (file)
--- a/tools/lib/traceevent/plugins/plugin_function.c
+++ b/tools/lib/traceevent/plugins/plugin_function.c
@@ -184,11 +184,52 @@ static int function_handler(struct trace_seq *s, struct tep_record *record,
        return 0;
 }
 
+static int
+trace_stack_handler(struct trace_seq *s, struct tep_record *record,
+                   struct tep_event *event, void *context)
+{
+       struct tep_format_field *field;
+       unsigned long long addr;
+       const char *func;
+       int long_size;
+       void *data = record->data;
+
+       field = tep_find_any_field(event, "caller");
+       if (!field) {
+               trace_seq_printf(s, "<CANT FIND FIELD %s>", "caller");
+               return 0;
+       }
+
+       trace_seq_puts(s, "<stack trace >\n");
+
+       long_size = tep_get_long_size(event->tep);
+
+       for (data += field->offset; data < record->data + record->size;
+            data += long_size) {
+               addr = tep_read_number(event->tep, data, long_size);
+
+               if ((long_size == 8 && addr == (unsigned long long)-1) ||
+                   ((int)addr == -1))
+                       break;
+
+               func = tep_find_function(event->tep, addr);
+               if (func)
+                       trace_seq_printf(s, "=> %s (%llx)\n", func, addr);
+               else
+                       trace_seq_printf(s, "=> %llx\n", addr);
+       }
+
+       return 0;
+}
+
 int TEP_PLUGIN_LOADER(struct tep_handle *tep)
 {
        tep_register_event_handler(tep, -1, "ftrace", "function",
                                   function_handler, NULL);
 
+       tep_register_event_handler(tep, -1, "ftrace", "kernel_stack",
+                                     trace_stack_handler, NULL);
+
        tep_plugin_add_options("ftrace", plugin_options);
 
        return 0;