[PATCH] perf tools: fix endian conversion reading event attr from header

[David Ahern <dsahern@gmail.com>]

The perf_event_attr struct has 2 __u32's at the top and need to
be swapped individually. With this change I was able to analyze
a perf.data collected in a 32-bit PPC VM on an x86 system. I
tested both 32-bit and 64-bit binaries for the Intel analysis
side; both read the PPC perf.data file correctly.

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 tools/perf/util/header.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index afb0849..8044c6f 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -877,9 +877,16 @@ int perf_session__read_header(struct perf_session *session, int fd)
 		struct perf_evsel *evsel;
 		off_t tmp;
 
-		if (perf_header__getbuffer64(header, fd, &f_attr, sizeof(f_attr)))
+		if (readn(fd, &f_attr, sizeof(f_attr)) <= 0)
 			goto out_errno;
 
+		if (header->needs_swap) {
+			f_attr.attr.type = bswap_32(f_attr.attr.type);
+			f_attr.attr.size = bswap_32(f_attr.attr.size);
+			mem_bswap_64(&f_attr.attr.config,
+				     sizeof(struct perf_event_attr) - 8);
+		}
+
 		tmp = lseek(fd, 0, SEEK_CUR);
 		evsel = perf_evsel__new(&f_attr.attr, i);
 
-- 
1.7.6