perf: Export struct perf_branch_entry to userspace

If PERF_SAMPLE_BRANCH_STACK is enabled then samples are returned
with the format { u64 from, to, flags } but the flags layout
is not specified.

This field has the type struct perf_branch_entry; move this
definition into include/uapi/linux/perf_event.h so users can
access these fields.

This is similar to the existing inclusion of perf_mem_data_src in
the include/uapi/linux/perf_event.h file.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1308231544420.1889@vincent-weaver-1.um.maine.edu
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index a77f43af72b8..408b8c730731 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -757,4 +757,28 @@ union perf_mem_data_src {
 #define PERF_MEM_S(a, s) \
         (((u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
 
+/*
+ * single taken branch record layout:
+ *
+ *      from: source instruction (may not always be a branch insn)
+ *        to: branch target
+ *   mispred: branch target was mispredicted
+ * predicted: branch target was predicted
+ *
+ * support for mispred, predicted is optional. In case it
+ * is not supported mispred = predicted = 0.
+ *
+ *     in_tx: running in a hardware transaction
+ *     abort: aborting a hardware transaction
+ */
+struct perf_branch_entry {
+        __u64   from;
+        __u64   to;
+        __u64   mispred:1,  /* target mispredicted */
+                predicted:1,/* target predicted */
+                in_tx:1,    /* in transaction */
+                abort:1,    /* transaction abort */
+                reserved:60;
+};
+
 #endif /* _UAPI_LINUX_PERF_EVENT_H */