[PATCH v2 7/9] perf callchain: Add support for cross-platform unwind

From: He Kuang
Date: Tue May 10 2016 - 03:41:37 EST

Use thread specific unwind ops to unwind cross-platform callchains.

Before this patch, unwind methods is suitable for local unwind, this
patch changes the fixed methods to thread/map related. Each time a map
is inserted, we find the target arch and see if this platform can be
remote unwind. In this patch, we test for x86 platform and only show
proper messages. The real unwind methods are not implemented, will be
introduced in next patch.

Common function used by both local unwind and remote unwind are
separated into new file 'unwind-libunwind_common.c'.

Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
---
tools/perf/config/Makefile | 19 +++++-
tools/perf/util/Build | 3 +-
tools/perf/util/thread.c | 5 +-
tools/perf/util/thread.h | 14 ++++-
tools/perf/util/unwind-libunwind.c | 73 +++++++++++-----------
tools/perf/util/unwind-libunwind_common.c | 100 ++++++++++++++++++++++++++++++
tools/perf/util/unwind.h | 35 ++++++++---
7 files changed, 196 insertions(+), 53 deletions(-)
create mode 100644 tools/perf/util/unwind-libunwind_common.c

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index a86b864..16f14b1 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -345,14 +345,24 @@ ifeq ($(ARCH),powerpc)
endif

ifndef NO_LIBUNWIND
+ have_libunwind =
ifeq ($(feature-libunwind-x86), 1)
- LIBUNWIND_LIBS += -lunwind-x86
$(call detected,CONFIG_LIBUNWIND_X86)
CFLAGS += -DHAVE_LIBUNWIND_X86_SUPPORT
+ LDFLAGS += -lunwind -lunwind-x86
+ have_libunwind = 1
endif

ifneq ($(feature-libunwind), 1)
msg := $(warning No libunwind found. Please install libunwind-dev[el] >= 1.1 and/or set LIBUNWIND_DIR);
+ NO_LOCAL_LIBUNWIND := 1
+ else
+ have_libunwind = 1
+ CFLAGS += -DHAVE_LIBUNWIND_LOCAL_SUPPORT
+ $(call detected,CONFIG_LOCAL_LIBUNWIND)
+ endif
+
+ ifneq ($(have_libunwind), 1)
NO_LIBUNWIND := 1
endif
endif
@@ -392,7 +402,7 @@ else
NO_DWARF_UNWIND := 1
endif

-ifndef NO_LIBUNWIND
+ifndef NO_LOCAL_LIBUNWIND
ifeq ($(ARCH),$(filter $(ARCH),arm arm64))
$(call feature_check,libunwind-debug-frame)
ifneq ($(feature-libunwind-debug-frame), 1)
@@ -403,12 +413,15 @@ ifndef NO_LIBUNWIND
# non-ARM has no dwarf_find_debug_frame() function:
CFLAGS += -DNO_LIBUNWIND_DEBUG_FRAME
endif
- CFLAGS += -DHAVE_LIBUNWIND_SUPPORT
EXTLIBS += $(LIBUNWIND_LIBS)
CFLAGS += $(LIBUNWIND_CFLAGS)
LDFLAGS += $(LIBUNWIND_LDFLAGS)
endif

+ifndef NO_LIBUNWIND
+ CFLAGS += -DHAVE_LIBUNWIND_SUPPORT
+endif
+
ifndef NO_LIBAUDIT
ifneq ($(feature-libaudit), 1)
msg := $(warning No libaudit.h found, disables 'trace' tool, please install audit-libs-devel or libaudit-dev);
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index ea4ac03..2e21529 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -97,7 +97,8 @@ libperf-$(CONFIG_DWARF) += probe-finder.o
libperf-$(CONFIG_DWARF) += dwarf-aux.o

libperf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
-libperf-$(CONFIG_LIBUNWIND) += unwind-libunwind.o
+libperf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
+libperf-$(CONFIG_LIBUNWIND) += unwind-libunwind_common.o

libperf-$(CONFIG_LIBBABELTRACE) += data-convert-bt.o

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 244c4f6..2274263 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -41,9 +41,6 @@ struct thread *thread__new(pid_t pid, pid_t tid)
thread->cpu = -1;
INIT_LIST_HEAD(&thread->comm_list);

- if (unwind__prepare_access(thread) < 0)
- goto err_thread;
-
comm_str = malloc(32);
if (!comm_str)
goto err_thread;
@@ -57,6 +54,8 @@ struct thread *thread__new(pid_t pid, pid_t tid)
list_add(&comm->list, &thread->comm_list);
atomic_set(&thread->refcnt, 1);
RB_CLEAR_NODE(&thread->rb_node);
+
+ register_null_unwind_libunwind_ops(thread);
}

return thread;
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index e214207..6f2d4cd 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -15,6 +15,17 @@

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;
@@ -36,7 +47,8 @@ struct thread {
void *priv;
struct thread_stack *ts;
#ifdef HAVE_LIBUNWIND_SUPPORT
- unw_addr_space_t addr_space;
+ unw_addr_space_t 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 b6eb317..2a8d24e 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -22,6 +22,9 @@
#include <unistd.h>
#include <sys/mman.h>
#include <linux/list.h>
+#ifdef ARCH_UNWIND_LIBUNWIND
+#include "libunwind-arch.h"
+#endif
#include <libunwind.h>
#include <libunwind-ptrace.h>
#include "callchain.h"
@@ -34,6 +37,22 @@
#include "debug.h"
#include "asm/bug.h"

+#ifndef ARCH_UNWIND_LIBUNWIND
+ #define LIBUNWIND__ARCH_REG_ID libunwind__arch_reg_id
+ #define LOCAL_UNWIND_LIBUNWIND
+ #undef UNWT_OBJ
+ #define UNWT_OBJ(x) _##x
+#else
+ #undef NO_LIBUNWIND_DEBUG_FRAME
+ #if defined(LIBUNWIND_ARM) && !defined(NO_LIBUNWIND_DEBUG_FRAME_ARM)
+ #elif defined(LIBUNWIND_AARCH64) && \
+ defined(NO_LIBUNWIND_DEBUG_FRAME_ARM_AARCH64)
+ #else
+ #define NO_LIBUNWIND_DEBUG_FRAME
+ #endif
+#endif
+
+
extern int
UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
unw_word_t ip,
@@ -579,7 +598,7 @@ static unw_accessors_t accessors = {
.get_proc_name = get_proc_name,
};

-int unwind__prepare_access(struct thread *thread)
+static int UNWT_OBJ(_unwind__prepare_access)(struct thread *thread)
{
if (callchain_param.record_mode != CALLCHAIN_DWARF)
return 0;
@@ -594,7 +613,7 @@ int unwind__prepare_access(struct thread *thread)
return 0;
}

-void unwind__flush_access(struct thread *thread)
+static void UNWT_OBJ(_unwind__flush_access)(struct thread *thread)
{
if (callchain_param.record_mode != CALLCHAIN_DWARF)
return;
@@ -602,7 +621,7 @@ void unwind__flush_access(struct thread *thread)
unw_flush_cache(thread->addr_space, 0, 0);
}

-void unwind__finish_access(struct thread *thread)
+static void UNWT_OBJ(_unwind__finish_access)(struct thread *thread)
{
if (callchain_param.record_mode != CALLCHAIN_DWARF)
return;
@@ -662,9 +681,10 @@ 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,
- struct thread *thread,
- struct perf_sample *data, int max_stack)
+static int UNWT_OBJ(_unwind__get_entries)(unwind_entry_cb_t cb, void *arg,
+ struct thread *thread,
+ struct perf_sample *data,
+ int max_stack)
{
struct unwind_info ui = {
.sample = data,
@@ -681,34 +701,17 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
return get_entries(&ui, cb, arg, max_stack);
}

-void unwind__get_arch(struct thread *thread, struct map *map)
-{
- char *arch;
- int is_64_bit;
-
- if (!thread->mg->machine->env)
- return;
-
- is_64_bit = dso_is_64_bit(map->dso, map);
- if (is_64_bit < 0)
- return;
-
- if (thread->addr_space)
- pr_debug("Thread map already set, 64bit is %d, dso=%s\n",
- is_64_bit, map->dso->name);
-
- arch = thread->mg->machine->env->arch;
+struct unwind_libunwind_ops
+UNWT_OBJ(unwind_libunwind_ops) = {
+ .prepare_access = UNWT_OBJ(_unwind__prepare_access),
+ .flush_access = UNWT_OBJ(_unwind__flush_access),
+ .finish_access = UNWT_OBJ(_unwind__finish_access),
+ .get_entries = UNWT_OBJ(_unwind__get_entries),
+};

- if (!strcmp(arch, "x86_64")
- || !strcmp(arch, "x86")
- || !strcmp(arch, "i686")) {
- pr_debug("Thread map is X86, 64bit is %d\n", is_64_bit);
- if (!is_64_bit)
-#ifdef HAVE_LIBUNWIND_X86_SUPPORT
- pr_err("target platform=%s is not implemented!\n",
- arch);
-#else
- pr_err("target platform=%s is not supported!\n", arch);
-#endif
- }
+#ifdef LOCAL_UNWIND_LIBUNWIND
+void register_local_unwind_libunwind_ops(struct thread *thread)
+{
+ thread->unwind_libunwind_ops = &UNWT_OBJ(unwind_libunwind_ops);
}
+#endif
diff --git a/tools/perf/util/unwind-libunwind_common.c b/tools/perf/util/unwind-libunwind_common.c
new file mode 100644
index 0000000..4bdd3b9
--- /dev/null
+++ b/tools/perf/util/unwind-libunwind_common.c
@@ -0,0 +1,100 @@
+#include "thread.h"
+#include "session.h"
+#include "unwind.h"
+#include "symbol.h"
+#include "debug.h"
+
+static int __null__prepare_access(struct thread *thread __maybe_unused)
+{
+ return 0;
+}
+
+static void __null__flush_access(struct thread *thread __maybe_unused)
+{
+}
+
+static void __null__finish_access(struct thread *thread __maybe_unused)
+{
+}
+
+static int __null__get_entries(unwind_entry_cb_t cb __maybe_unused,
+ void *arg __maybe_unused,
+ struct thread *thread __maybe_unused,
+ struct perf_sample *data __maybe_unused,
+ int max_stack __maybe_unused)
+{
+ return 0;
+}
+
+static struct unwind_libunwind_ops null_unwind_libunwind_ops = {
+ .prepare_access = __null__prepare_access,
+ .flush_access = __null__flush_access,
+ .finish_access = __null__finish_access,
+ .get_entries = __null__get_entries,
+};
+
+void register_null_unwind_libunwind_ops(struct thread *thread)
+{
+ thread->unwind_libunwind_ops = &null_unwind_libunwind_ops;
+ if (thread->mg)
+ pr_err("unwind: target platform=%s unwind unsupported\n",
+ thread->mg->machine->env->arch);
+}
+
+void register_unwind_libunwind_ops(struct unwind_libunwind_ops *ops,
+ struct thread *thread)
+{
+ thread->unwind_libunwind_ops = ops;
+}
+
+void unwind__flush_access(struct thread *thread)
+{
+ thread->unwind_libunwind_ops->flush_access(thread);
+}
+
+void unwind__finish_access(struct thread *thread)
+{
+ thread->unwind_libunwind_ops->finish_access(thread);
+}
+
+void unwind__get_arch(struct thread *thread, struct map *map)
+{
+ char *arch;
+ int is_64_bit;
+ int use_local_unwind = 0;
+
+ if (!thread->mg->machine->env)
+ return;
+
+ is_64_bit = dso_is_64_bit(map->dso, map);
+ if (is_64_bit < 0)
+ return;
+
+ if (thread->addr_space)
+ pr_debug("unwind: thread map already set, 64bit is %d, dso=%s\n",
+ is_64_bit, map->dso->name);
+
+ arch = thread->mg->machine->env->arch;
+
+ if (!strcmp(arch, "x86_64")
+ || !strcmp(arch, "x86")
+ || !strcmp(arch, "i686")) {
+ pr_debug("unwind: thread map is X86, 64bit is %d\n", is_64_bit);
+ if (!is_64_bit) {
+#ifdef HAVE_LIBUNWIND_X86_SUPPORT
+ pr_err("unwind: target platform=%s is not implemented\n",
+ arch);
+#endif
+ register_null_unwind_libunwind_ops(thread);
+ } else
+ use_local_unwind = 1;
+ } else {
+ use_local_unwind = 1;
+ }
+
+ if (use_local_unwind)
+ register_local_unwind_libunwind_ops(thread);
+
+ if (thread->unwind_libunwind_ops->prepare_access(thread) < 0)
+ return;
+}
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 889d630..e045600 100644
--- a/tools/perf/util/unwind.h
+++ b/tools/perf/util/unwind.h
@@ -21,20 +21,38 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
/* libunwind specific */
#ifdef HAVE_LIBUNWIND_SUPPORT
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 unwind__get_arch(struct thread *thread, struct map *map);
-#else
-static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
-{
- return 0;
+void register_unwind_libunwind_ops(struct unwind_libunwind_ops *ops,
+ struct thread *thread);
+void register_null_unwind_libunwind_ops(struct thread *thread);
+
+#ifndef HAVE_LIBUNWIND_LOCAL_SUPPORT
+static inline void
+register_local_unwind_libunwind_ops(struct thread *thread) {
+ register_null_unwind_libunwind_ops(thread);
}
+#else
+void register_local_unwind_libunwind_ops(struct thread *thread);
+#endif

+#define unwind__get_entries(cb, arg, \
+ thread, \
+ data, max_stack) \
+ thread->unwind_libunwind_ops->get_entries(cb, \
+ arg, \
+ thread, \
+ data, \
+ max_stack)
+
+#else
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 unwind__get_arch(struct thread *thread __maybe_unused,
struct map *map __maybe_unused) {}
+static inline void
+register_null_unwind_libunwind_ops(struct thread *thread __maybe_unused) {}
#endif
#else
static inline int
@@ -47,14 +65,11 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
return 0;
}

-static inline int unwind__prepare_access(struct thread *thread __maybe_unused)
-{
- return 0;
-}
-
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 unwind__get_arch(struct thread *thread __maybe_unused,
struct map *map __maybe_unused) {}
+static inline void
+register_null_unwind_libunwind_ops(struct thread *thread __maybe_unused) {}
#endif /* HAVE_DWARF_UNWIND_SUPPORT */
#endif /* __UNWIND_H */
--
1.8.5.2