perf unwind: Fix libunwind when tid != pid

Commit e5adfc3e7e77 ("perf map: Synthesize maps only for thread group
leader") changed the recording side so that we no longer get mmap events
for threads other than the thread group leader (when synthesising these
events for threads which exist before perf is started).

When a file recorded after this change is loaded, the lack of mmap
records mean that unwinding is not set up for any other threads.

This can be seen in a simple record/report scenario:

	perf record --call-graph=dwarf -t $TID
	perf report

If $TID is a process ID then the report will show call graphs, but if
$TID is a secondary thread the output is as if --call-graph=none was
specified.

Following the rationale in that commit, move the libunwind fields into
struct map_groups and update the libunwind functions to take this
instead of the struct thread.  This is only required for
unwind__finish_access which must now be called from map_groups__delete
and the others are changed for symmetry.

Note that unwind__get_entries keeps the thread argument since it is
required for symbol lookup and the libdw unwind provider uses the thread
ID.

Signed-off-by: John Keeping <john@metanate.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e5adfc3e7e77 ("perf map: Synthesize maps only for thread group leader")
Link: http://lkml.kernel.org/r/20190815100146.28842-2-john@metanate.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 17 insertions, 17 deletions

diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index c0811977d7d5..b843f9d0a9ea 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -11,13 +11,13 @@ struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
 
-static void unwind__register_ops(struct thread *thread,
+static void unwind__register_ops(struct map_groups *mg,
 			  struct unwind_libunwind_ops *ops)
 {
-	thread->unwind_libunwind_ops = ops;
+	mg->unwind_libunwind_ops = ops;
 }
 
-int unwind__prepare_access(struct thread *thread, struct map *map,
+int unwind__prepare_access(struct map_groups *mg, struct map *map,
 			   bool *initialized)
 {
 	const char *arch;
@@ -28,7 +28,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	if (!dwarf_callchain_users)
 		return 0;
 
-	if (thread->addr_space) {
+	if (mg->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
 			 map->dso->name);
 		if (initialized)
@@ -37,14 +37,14 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 	}
 
 	/* env->arch is NULL for live-mode (i.e. perf top) */
-	if (!thread->mg->machine->env || !thread->mg->machine->env->arch)
+	if (!mg->machine->env || !mg->machine->env->arch)
 		goto out_register;
 
-	dso_type = dso__type(map->dso, thread->mg->machine);
+	dso_type = dso__type(map->dso, mg->machine);
 	if (dso_type == DSO__TYPE_UNKNOWN)
 		return 0;
 
-	arch = perf_env__arch(thread->mg->machine->env);
+	arch = perf_env__arch(mg->machine->env);
 
 	if (!strcmp(arch, "x86")) {
 		if (dso_type != DSO__TYPE_64BIT)
@@ -59,37 +59,37 @@ int unwind__prepare_access(struct thread *thread, struct map *map,
 		return 0;
 	}
 out_register:
-	unwind__register_ops(thread, ops);
+	unwind__register_ops(mg, ops);
 
-	err = thread->unwind_libunwind_ops->prepare_access(thread);
+	err = mg->unwind_libunwind_ops->prepare_access(mg);
 	if (initialized)
 		*initialized = err ? false : true;
 	return err;
 }
 
-void unwind__flush_access(struct thread *thread)
+void unwind__flush_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->flush_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->flush_access(mg);
 }
 
-void unwind__finish_access(struct thread *thread)
+void unwind__finish_access(struct map_groups *mg)
 {
 	if (!dwarf_callchain_users)
 		return;
 
-	if (thread->unwind_libunwind_ops)
-		thread->unwind_libunwind_ops->finish_access(thread);
+	if (mg->unwind_libunwind_ops)
+		mg->unwind_libunwind_ops->finish_access(mg);
 }
 
 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			 struct thread *thread,
 			 struct perf_sample *data, int max_stack)
 {
-	if (thread->unwind_libunwind_ops)
-		return thread->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
+	if (thread->mg->unwind_libunwind_ops)
+		return thread->mg->unwind_libunwind_ops->get_entries(cb, arg, thread, data, max_stack);
 	return 0;
 }