Hook into session processing so that AUX area decoding can synthesize
events transparently to the tools.

The advantages of transparent decoding are that tools can be used
directly with perf.data files containing AUX area tracing data, which is
easier for the user and more efficient than having a separate decoding
tool.

This will work as follows:

1. Tools will feed auxtrace events to the decoder using
   perf_tool->auxtrace() (support for that still to come).

2. The decoder can process side-band events as needed due
   to the auxtrace->process_event() hook.

3. The decoder can deliver synthesized events into the
   event stream using perf_session__deliver_synth_event().

Note the expectation is that decoding will work on data that is
time-ordered with respect to the per-cpu or per-thread contexts that
were recorded.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-9-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Add support for reading from the AUX area tracing mmap and synthesizing
AUX area tracing events.

This patch introduces an abstraction for recording AUX area data.

Recording is initialized by auxtrace_record__init() which is a weak
function to be implemented by the architecture to provide recording
callbacks.

Recording is mainly handled by auxtrace_mmap__read() and
perf_event__synthesize_auxtrace() but there are callbacks for
miscellaneous needs including validating and processing user options,
populating private data in auxtrace_info_event, and freeing the
structure when finished.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-5-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

This patch supports the addition to the kernel of AUX area buffers that
can be mmapped separately from the perf-events buffer.

The AUX buffer can be configured to contain hardware-produced trace
information. The first implementation will support Intel BTS and Intel
PT.

One auxtrace buffer is mmapped per perf-events buffer.  If the requested
auxtrace buffer size is zero, which it will be until further support is
added, then no auxtrace mmapping is attempted.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-3-git-send-email-adrian.hunter@intel.com
[ Fixed conflict in evlist.h ]
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>