linux-kernel - [PATCH 4/4] perf, tool: Fix 32 bit values endianity swap for sample_id

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Date:	Fri,  4 May 2012 19:11:33 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	acme@...hat.com, a.p.zijlstra@...llo.nl, mingo@...e.hu,
	paulus@...ba.org, cjashfor@...ux.vnet.ibm.com, fweisbec@...il.com
Cc:	linux-kernel@...r.kernel.org, Jiri Olsa <jolsa@...hat.com>
Subject: [PATCH 4/4] perf, tool: Fix 32 bit values endianity swap for sample_id_all header

We swap the sample_id_all header by u64 pointers. Some members
of the header happen to be 32 bit values. We need to handle them
separatelly.

Signed-off-by: Jiri Olsa <jolsa@...hat.com>
---
 tools/perf/util/evsel.c |   32 +++++++++++++++++++++++++-------
 1 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 8c13dbc..ea053b7 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -403,16 +403,27 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel,
 }
 
 static int perf_event__parse_id_sample(const union perf_event *event, u64 type,
-				       struct perf_sample *sample)
+				       struct perf_sample *sample,
+				       bool swapped)
 {
 	const u64 *array = event->sample.array;
+	union {
+		u64 val64;
+		u32 val32[2];
+	} u;
 
 	array += ((event->header.size -
 		   sizeof(event->header)) / sizeof(u64)) - 1;
 
 	if (type & PERF_SAMPLE_CPU) {
-		u32 *p = (u32 *)array;
-		sample->cpu = *p;
+		u.val64 = *array;
+		if (swapped) {
+			/* undo swap of u64, then swap on individual u32s */
+			u.val64 = bswap_64(u.val64);
+			u.val32[0] = bswap_32(u.val32[0]);
+		}
+
+		sample->cpu = u.val32[0];
 		array--;
 	}
 
@@ -432,9 +443,16 @@ static int perf_event__parse_id_sample(const union perf_event *event, u64 type,
 	}
 
 	if (type & PERF_SAMPLE_TID) {
-		u32 *p = (u32 *)array;
-		sample->pid = p[0];
-		sample->tid = p[1];
+		u.val64 = *array;
+		if (swapped) {
+			/* undo swap of u64, then swap on individual u32s */
+			u.val64 = bswap_64(u.val64);
+			u.val32[0] = bswap_32(u.val32[0]);
+			u.val32[1] = bswap_32(u.val32[1]);
+		}
+
+		sample->pid = u.val32[0];
+		sample->tid = u.val32[1];
 	}
 
 	return 0;
@@ -474,7 +492,7 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
 	if (event->header.type != PERF_RECORD_SAMPLE) {
 		if (!sample_id_all)
 			return 0;
-		return perf_event__parse_id_sample(event, type, data);
+		return perf_event__parse_id_sample(event, type, data, swapped);
 	}
 
 	array = event->sample.array;
-- 
1.7.7.6

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