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Subject[PATCH v6 03/11] perf tools: Introducing struct unwind_libunwind_ops for local unwind
Date
Currently, libunwind operations are fixed, and they are chosen
according to the host architecture. This will lead a problem that if a
thread is run as x86_32 on x86_64 machine, perf will use libunwind
methods for x86_64 to parse the callchain and get wrong result.

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

Signed-off-by: He Kuang <hekuang@huawei.com>
---
tools/perf/util/thread.c | 2 ++
tools/perf/util/thread.h | 14 +++++++++-
tools/perf/util/unwind-libunwind.c | 55 ++++++++++++++++++++++++++++++++++----
tools/perf/util/unwind.h | 5 ++++
4 files changed, 70 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 45fcb71..6d3900c 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -43,6 +43,8 @@ struct thread *thread__new(pid_t pid, pid_t tid)
thread->cpu = -1;
INIT_LIST_HEAD(&thread->comm_list);

+ register_local_unwind_libunwind_ops(thread);
+
if (unwind__prepare_access(thread) < 0)
goto err_thread;

diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index aa3a8ff..647b011 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -12,6 +12,17 @@

struct thread_stack;

+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);
+};
+
struct thread {
union {
struct rb_node rb_node;
@@ -33,7 +44,8 @@ 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..0277b22 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -23,7 +23,6 @@
#include <sys/mman.h>
#include <linux/list.h>
#include <libunwind.h>
-#include <libunwind-ptrace.h>
#include "callchain.h"
#include "thread.h"
#include "session.h"
@@ -579,7 +578,7 @@ 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 +593,7 @@ 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 +601,7 @@ 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 +661,7 @@ 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 +679,49 @@ 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,
+};
+
+void register_local_unwind_libunwind_ops(struct thread *thread)
+{
+ thread->unwind_libunwind_ops = &_unwind_libunwind_ops;
+}
+
+int unwind__prepare_access(struct thread *thread)
+{
+ if (thread->unwind_libunwind_ops)
+ return thread->unwind_libunwind_ops->prepare_access(thread);
+ else
+ return 0;
+}
+
+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);
+ else
+ return 0;
+}
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 12790cf..5f36415 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -24,6 +24,7 @@ int libunwind__arch_reg_id(int regnum);
int unwind__prepare_access(struct thread *thread);
void unwind__flush_access(struct thread *thread);
void unwind__finish_access(struct thread *thread);
+void register_local_unwind_libunwind_ops(struct thread *thread);
#else
static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
{
@@ -32,6 +33,8 @@ static inline int unwind__prepare_access(struct thread *thread __maybe_unused)

static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void
+register_local_unwind_libunwind_ops(struct thread *thread __maybe_unused) {}
#endif
#else
static inline int
@@ -51,5 +54,7 @@ static inline int unwind__prepare_access(struct thread *thread __maybe_unused)

static inline void unwind__flush_access(struct thread *thread __maybe_unused) {}
static inline void unwind__finish_access(struct thread *thread __maybe_unused) {}
+static inline void
+register_local_unwind_libunwind_ops(struct thread *thread __maybe_unused) {}
#endif /* HAVE_DWARF_UNWIND_SUPPORT */
#endif /* __UNWIND_H */
--
1.8.5.2
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