perf tools: Fix endian conversion reading event attr from file header

commit eda3913bb70ecebac13adccffe1e7f96e93cee02 upstream.

The perf_event_attr struct has two __u32's at the top and
they 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.

-v2:
 - changed the existing perf_event__attr_swap() to swap only elements
   of perf_event_attr and exported it for use in swapping the
   attributes in the file header
 - updated swap_ops used for processing events

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: acme@ghostprotocols.net
Cc: peterz@infradead.org
Cc: paulus@samba.org
Link: http://lkml.kernel.org/r/1310754849-12474-1-git-send-email-dsahern@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 23 insertions, 13 deletions

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index afb0849fe53..cb2959a3fb4 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -877,9 +877,12 @@ 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)
+                        perf_event__attr_swap(&f_attr.attr);
+
                 tmp = lseek(fd, 0, SEEK_CUR);
                 evsel = perf_evsel__new(&f_attr.attr, i);
 
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index f5a8fbdd3f7..2dbf0abd8e1 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -407,20 +407,26 @@ static void perf_event__read_swap(union perf_event *event)
         event->read.id           = bswap_64(event->read.id);
 }
 
-static void perf_event__attr_swap(union perf_event *event)
+/* exported for swapping attributes in file header */
+void perf_event__attr_swap(struct perf_event_attr *attr)
+{
+        attr->type              = bswap_32(attr->type);
+        attr->size              = bswap_32(attr->size);
+        attr->config            = bswap_64(attr->config);
+        attr->sample_period     = bswap_64(attr->sample_period);
+        attr->sample_type       = bswap_64(attr->sample_type);
+        attr->read_format       = bswap_64(attr->read_format);
+        attr->wakeup_events     = bswap_32(attr->wakeup_events);
+        attr->bp_type           = bswap_32(attr->bp_type);
+        attr->bp_addr           = bswap_64(attr->bp_addr);
+        attr->bp_len            = bswap_64(attr->bp_len);
+}
+
+static void perf_event__hdr_attr_swap(union perf_event *event)
 {
         size_t size;
 
-        event->attr.attr.type           = bswap_32(event->attr.attr.type);
-        event->attr.attr.size           = bswap_32(event->attr.attr.size);
-        event->attr.attr.config         = bswap_64(event->attr.attr.config);
-        event->attr.attr.sample_period  = bswap_64(event->attr.attr.sample_period);
-        event->attr.attr.sample_type    = bswap_64(event->attr.attr.sample_type);
-        event->attr.attr.read_format    = bswap_64(event->attr.attr.read_format);
-        event->attr.attr.wakeup_events  = bswap_32(event->attr.attr.wakeup_events);
-        event->attr.attr.bp_type        = bswap_32(event->attr.attr.bp_type);
-        event->attr.attr.bp_addr        = bswap_64(event->attr.attr.bp_addr);
-        event->attr.attr.bp_len         = bswap_64(event->attr.attr.bp_len);
+        perf_event__attr_swap(&event->attr.attr);
 
         size = event->header.size;
         size -= (void *)&event->attr.id - (void *)event;
@@ -448,7 +454,7 @@ static perf_event__swap_op perf_event__swap_ops[] = {
         [PERF_RECORD_LOST]                = perf_event__all64_swap,
         [PERF_RECORD_READ]                = perf_event__read_swap,
         [PERF_RECORD_SAMPLE]              = perf_event__all64_swap,
-        [PERF_RECORD_HEADER_ATTR]         = perf_event__attr_swap,
+        [PERF_RECORD_HEADER_ATTR]         = perf_event__hdr_attr_swap,
         [PERF_RECORD_HEADER_EVENT_TYPE]   = perf_event__event_type_swap,
         [PERF_RECORD_HEADER_TRACING_DATA] = perf_event__tracing_data_swap,
         [PERF_RECORD_HEADER_BUILD_ID]     = NULL,
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 66d4e149087..b84c003189f 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -112,6 +112,7 @@ int perf_session__set_kallsyms_ref_reloc_sym(struct map **maps,
                                              u64 addr);
 
 void mem_bswap_64(void *src, int byte_size);
+void perf_event__attr_swap(struct perf_event_attr *attr);
 
 int perf_session__create_kernel_maps(struct perf_session *self);