[PATCH 3/3] perf: Fix unaligned accesses while fetching trace values

From: Frederic Weisbecker
Date: Thu May 20 2010 - 05:44:39 EST

Accessing trace values of an 8 size may end up in a segfault
on archs that can't deal with misaligned access, which is the
case for sparc 64. This is because PERF_SAMPLE_RAW are aligned
to 4 and not to 8.

Fix this on the macros that get the values of 8 size.

This fixes segfaults on perf tools in sparc 64.

Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Tom Zanussi <tzanussi@xxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
tools/perf/util/trace-event.h | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/trace-event.h b/tools/perf/util/trace-event.h
index 406d452..b3e86b1 100644
--- a/tools/perf/util/trace-event.h
+++ b/tools/perf/util/trace-event.h
@@ -233,7 +233,12 @@ static inline unsigned long long __data2host8(unsigned long long data)

#define data2host2(ptr) __data2host2(*(unsigned short *)ptr)
#define data2host4(ptr) __data2host4(*(unsigned int *)ptr)
-#define data2host8(ptr) __data2host8(*(unsigned long long *)ptr)
+#define data2host8(ptr) ({ \
+ unsigned long long __val; \
+ \
+ memcpy(&__val, (ptr), sizeof(unsigned long long)); \
+ __data2host8(__val); \

extern int header_page_ts_offset;
extern int header_page_ts_size;

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