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Subject[038/102] perf tools: Fix endian conversion reading event attr from file header
3.0-stable review patch.  If anyone has any objections, please let us know.

------------------
From: David Ahern <dsahern@gmail.com>

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>

---
tools/perf/util/header.c | 5 ++++-
tools/perf/util/session.c | 30 ++++++++++++++++++------------
tools/perf/util/session.h | 1 +
3 files changed, 23 insertions(+), 13 deletions(-)
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -877,9 +877,12 @@ int perf_session__read_header(struct per
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);

--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -407,20 +407,26 @@ static void perf_event__read_swap(union
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__s
[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,
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -112,6 +112,7 @@ int perf_session__set_kallsyms_ref_reloc
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);




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