tools lib traceevent: Allow setting an alternative symbol resolver
The perf tools have a symbol resolver that includes solving kernel
symbols using either kallsyms or ELF symtabs, and it also is using
libtraceevent to format the trace events fields, including via
subsystem specific plugins, like the "timer" one.
To solve fields like "timer:hrtimer_start"'s "function", libtraceevent
needs a way to map from its value to a function name and addr.
This patch provides a way for tools that already have symbol resolving
facilities to ask libtraceevent to use it when needing to resolve
kernel symbols.
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-fdx1fazols17w5py26ia3bwh@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index cc25f05..fcd8a9e 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -418,7 +418,7 @@
}
static struct func_map *
-find_func(struct pevent *pevent, unsigned long long addr)
+__find_func(struct pevent *pevent, unsigned long long addr)
{
struct func_map *func;
struct func_map key;
@@ -434,6 +434,71 @@
return func;
}
+struct func_resolver {
+ pevent_func_resolver_t *func;
+ void *priv;
+ struct func_map map;
+};
+
+/**
+ * pevent_set_function_resolver - set an alternative function resolver
+ * @pevent: handle for the pevent
+ * @resolver: function to be used
+ * @priv: resolver function private state.
+ *
+ * Some tools may have already a way to resolve kernel functions, allow them to
+ * keep using it instead of duplicating all the entries inside
+ * pevent->funclist.
+ */
+int pevent_set_function_resolver(struct pevent *pevent,
+ pevent_func_resolver_t *func, void *priv)
+{
+ struct func_resolver *resolver = malloc(sizeof(*resolver));
+
+ if (resolver == NULL)
+ return -1;
+
+ resolver->func = func;
+ resolver->priv = priv;
+
+ free(pevent->func_resolver);
+ pevent->func_resolver = resolver;
+
+ return 0;
+}
+
+/**
+ * pevent_reset_function_resolver - reset alternative function resolver
+ * @pevent: handle for the pevent
+ *
+ * Stop using whatever alternative resolver was set, use the default
+ * one instead.
+ */
+void pevent_reset_function_resolver(struct pevent *pevent)
+{
+ free(pevent->func_resolver);
+ pevent->func_resolver = NULL;
+}
+
+static struct func_map *
+find_func(struct pevent *pevent, unsigned long long addr)
+{
+ struct func_map *map;
+
+ if (!pevent->func_resolver)
+ return __find_func(pevent, addr);
+
+ map = &pevent->func_resolver->map;
+ map->mod = NULL;
+ map->addr = addr;
+ map->func = pevent->func_resolver->func(pevent->func_resolver->priv,
+ &map->addr, &map->mod);
+ if (map->func == NULL)
+ return NULL;
+
+ return map;
+}
+
/**
* pevent_find_function - find a function by a given address
* @pevent: handle for the pevent
@@ -6564,6 +6629,7 @@
free(pevent->trace_clock);
free(pevent->events);
free(pevent->sort_events);
+ free(pevent->func_resolver);
free(pevent);
}