[PATCH 4.4 217/230] perf auxtrace: Define auxtrace record alignment

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Adrian Hunter <adrian.hunter@xxxxxxxxx>

commit c3fcadf0bb765faf45d6d562246e1d08885466df upstream.

Define auxtrace record alignment so that it can be referenced elsewhere.

Note this is preparation for patch "perf intel-pt: Fix overlap calculation
for padding"

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20190206103947.15750-2-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 tools/perf/util/auxtrace.c |    4 ++--
 tools/perf/util/auxtrace.h |    3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1226,9 +1226,9 @@ static int __auxtrace_mmap__read(struct
 	}
 
 	/* padding must be written by fn() e.g. record__process_auxtrace() */
-	padding = size & 7;
+	padding = size & (PERF_AUXTRACE_RECORD_ALIGNMENT - 1);
 	if (padding)
-		padding = 8 - padding;
+		padding = PERF_AUXTRACE_RECORD_ALIGNMENT - padding;
 
 	memset(&ev, 0, sizeof(ev));
 	ev.auxtrace.header.type = PERF_RECORD_AUXTRACE;
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -37,6 +37,9 @@ struct record_opts;
 struct auxtrace_info_event;
 struct events_stats;
 
+/* Auxtrace records must have the same alignment as perf event records */
+#define PERF_AUXTRACE_RECORD_ALIGNMENT 8
+
 enum auxtrace_type {
 	PERF_AUXTRACE_UNKNOWN,
 	PERF_AUXTRACE_INTEL_PT,