linux-kernel - [PATCH v3 1/7 UPDATE] perf tools: Find vdso with the consider of cross-platform

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Date:	Fri, 13 May 2016 08:51:49 +0000
From:	He Kuang <hekuang@...wei.com>
To:	<peterz@...radead.org>, <mingo@...hat.com>, <acme@...nel.org>,
	<alexander.shishkin@...ux.intel.com>, <jolsa@...hat.com>,
	<wangnan0@...wei.com>, <hekuang@...wei.com>, <jpoimboe@...hat.com>,
	<ak@...ux.intel.com>, <eranian@...gle.com>, <namhyung@...nel.org>,
	<adrian.hunter@...el.com>, <sukadev@...ux.vnet.ibm.com>,
	<masami.hiramatsu.pt@...achi.com>, <tumanova@...ux.vnet.ibm.com>,
	<kan.liang@...el.com>, <penberg@...nel.org>, <dsahern@...il.com>
CC:	<linux-kernel@...r.kernel.org>
Subject: [PATCH v3 1/7 UPDATE] perf tools: Find vdso with the consider of cross-platform

There's a problem in machine__findnew_vdso(), vdso buildid generated
by a 32-bit machine stores it with the name 'vdso', but when
processing buildid on a 64-bit machine with the same 'perf.data', perf
will search for vdso named as 'vdso32' and get failed.

This patch tries to find the exsiting dsos in machine->dsos by thread
dso_type. 64-bit thread tries to find vdso with name 'vdso', because
all 64-bit vdso is named as that. 32-bit thread first tries to find
vdso with name 'vdso32' if this thread was run on 64-bit machine, if
failed, then it tries 'vdso' which indicates that the thread was run
on 32-bit machine when recording.

Signed-off-by: He Kuang <hekuang@...wei.com>
---
 tools/perf/util/vdso.c | 40 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 37 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c
index 44d440d..99f4a3d 100644
--- a/tools/perf/util/vdso.c
+++ b/tools/perf/util/vdso.c
@@ -134,8 +134,6 @@ static struct dso *__machine__addnew_vdso(struct machine *machine, const char *s
 	return dso;
 }
 
-#if BITS_PER_LONG == 64
-
 static enum dso_type machine__thread_dso_type(struct machine *machine,
 					      struct thread *thread)
 {
@@ -156,6 +154,8 @@ static enum dso_type machine__thread_dso_type(struct machine *machine,
 	return dso_type;
 }
 
+#if BITS_PER_LONG == 64
+
 static int vdso__do_copy_compat(FILE *f, int fd)
 {
 	char buf[4096];
@@ -283,8 +283,38 @@ static int __machine__findnew_vdso_compat(struct machine *machine,
 
 #endif
 
+static struct dso *machine__find_vdso(struct machine *machine,
+				      struct thread *thread)
+{
+	struct dso *dso = NULL;
+	enum dso_type dso_type;
+
+	dso_type = machine__thread_dso_type(machine, thread);
+	switch (dso_type) {
+	case DSO__TYPE_32BIT:
+		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO32, true);
+		if (!dso)
+			dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
+					   true);
+		break;
+	case DSO__TYPE_X32BIT:
+		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSOX32, true);
+		if (!dso)
+			dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO,
+					   true);
+		break;
+	case DSO__TYPE_64BIT:
+	case DSO__TYPE_UNKNOWN:
+	default:
+		dso = __dsos__find(&machine->dsos, DSO__NAME_VDSO, true);
+		break;
+	}
+
+	return dso;
+}
+
 struct dso *machine__findnew_vdso(struct machine *machine,
-				  struct thread *thread __maybe_unused)
+				  struct thread *thread)
 {
 	struct vdso_info *vdso_info;
 	struct dso *dso = NULL;
@@ -297,6 +327,10 @@ struct dso *machine__findnew_vdso(struct machine *machine,
 	if (!vdso_info)
 		goto out_unlock;
 
+	dso = machine__find_vdso(machine, thread);
+	if (dso)
+		goto out_unlock;
+
 #if BITS_PER_LONG == 64
 	if (__machine__findnew_vdso_compat(machine, thread, vdso_info, &dso))
 		goto out_unlock;
-- 
1.8.5.2