[tip:perf/core] perf unwind: Introduce 'struct unwind_libunwind_ops' for local unwind

[tip-bot for He Kuang]

Commit-ID:  f83c04156c1483f16ac548516f41212cf244e441
Gitweb:     http://git.kernel.org/tip/f83c04156c1483f16ac548516f41212cf244e441
Author:     He Kuang <hekuang@xxxxxxxxxx>
AuthorDate: Fri, 3 Jun 2016 03:33:12 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 7 Jun 2016 12:08:52 -0300

perf unwind: Introduce 'struct unwind_libunwind_ops' for local unwind

Currently, libunwind operations are fixed, and they are chosen according
to the host architecture. This will lead to a problem that if a thread
is run as x86_32 on a x86_64 machine, perf will use libunwind methods
for x86_64 to parse the callchain and get wrong results.

This patch changes the fixed methods of libunwind operations to be
thread/map related, and each thread can have individual libunwind
operations. Local libunwind methods are registered as default value.

Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Ekaterina Tumanova <tumanova@xxxxxxxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1464924803-22214-4-git-send-email-hekuang@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/thread.h           |  4 ++-
 tools/perf/util/unwind-libunwind.c | 53 +++++++++++++++++++++++++++++++++++---
 tools/perf/util/unwind.h           |  9 +++++++
 3 files changed, 61 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 4c9f0aa..07ffb18 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -11,6 +11,7 @@
 #include <intlist.h>
 
 struct thread_stack;
+struct unwind_libunwind_ops;
 
 struct thread {
 	union {
@@ -33,7 +34,8 @@ struct thread {
 	void			*priv;
 	struct thread_stack	*ts;
 #ifdef HAVE_LIBUNWIND_SUPPORT
-	void			*addr_space;
+	void				*addr_space;
+	struct unwind_libunwind_ops	*unwind_libunwind_ops;
 #endif
 };
 
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 63687d3..b0c5db1 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -579,7 +579,7 @@ static unw_accessors_t accessors = {
 	.get_proc_name		= get_proc_name,
 };
 
-int unwind__prepare_access(struct thread *thread)
+static int _unwind__prepare_access(struct thread *thread)
 {
 	if (callchain_param.record_mode != CALLCHAIN_DWARF)
 		return 0;
@@ -594,7 +594,7 @@ int unwind__prepare_access(struct thread *thread)
 	return 0;
 }
 
-void unwind__flush_access(struct thread *thread)
+static void _unwind__flush_access(struct thread *thread)
 {
 	if (callchain_param.record_mode != CALLCHAIN_DWARF)
 		return;
@@ -602,7 +602,7 @@ void unwind__flush_access(struct thread *thread)
 	unw_flush_cache(thread->addr_space, 0, 0);
 }
 
-void unwind__finish_access(struct thread *thread)
+static void _unwind__finish_access(struct thread *thread)
 {
 	if (callchain_param.record_mode != CALLCHAIN_DWARF)
 		return;
@@ -662,7 +662,7 @@ static int get_entries(struct unwind_info *ui, unwind_entry_cb_t cb,
 	return ret;
 }
 
-int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
+static int _unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			struct thread *thread,
 			struct perf_sample *data, int max_stack)
 {
@@ -680,3 +680,48 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 
 	return get_entries(&ui, cb, arg, max_stack);
 }
+
+static struct unwind_libunwind_ops
+_unwind_libunwind_ops = {
+	.prepare_access = _unwind__prepare_access,
+	.flush_access   = _unwind__flush_access,
+	.finish_access  = _unwind__finish_access,
+	.get_entries    = _unwind__get_entries,
+};
+
+struct unwind_libunwind_ops *
+local_unwind_libunwind_ops = &_unwind_libunwind_ops;
+
+static void unwind__register_ops(struct thread *thread,
+				 struct unwind_libunwind_ops *ops)
+{
+	thread->unwind_libunwind_ops = ops;
+}
+
+int unwind__prepare_access(struct thread *thread)
+{
+	unwind__register_ops(thread, local_unwind_libunwind_ops);
+
+	return thread->unwind_libunwind_ops->prepare_access(thread);
+}
+
+void unwind__flush_access(struct thread *thread)
+{
+	if (thread->unwind_libunwind_ops)
+		thread->unwind_libunwind_ops->flush_access(thread);
+}
+
+void unwind__finish_access(struct thread *thread)
+{
+	if (thread->unwind_libunwind_ops)
+		thread->unwind_libunwind_ops->finish_access(thread);
+}
+
+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);
+	return 0;
+}
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 12790cf..bbd73d9 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -14,6 +14,15 @@ struct unwind_entry {
 
 typedef int (*unwind_entry_cb_t)(struct unwind_entry *entry, void *arg);
 
+struct unwind_libunwind_ops {
+	int (*prepare_access)(struct thread *thread);
+	void (*flush_access)(struct thread *thread);
+	void (*finish_access)(struct thread *thread);
+	int (*get_entries)(unwind_entry_cb_t cb, void *arg,
+			   struct thread *thread,
+			   struct perf_sample *data, int max_stack);
+};
+
 #ifdef HAVE_DWARF_UNWIND_SUPPORT
 int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 			struct thread *thread,