7dde51767c
CoreSight PMU supports aux-buffer for the ETM tracing. The trace generated by the ETM (associated with individual CPUs, like Intel PT) is captured by a separate IP (CoreSight TMC-ETR/ETF until now). The TMC-ETR applies formatting of the raw ETM trace data, as it can collect traces from multiple ETMs, with the TraceID to indicate the source of a given trace packet. Arm Trace Buffer Extension is new "sink" IP, attached to individual CPUs and thus do not provide additional formatting, like TMC-ETR. Additionally, a system could have both TRBE *and* TMC-ETR for the trace collection. e.g, TMC-ETR could be used as a single trace buffer to collect data from multiple ETMs to correlate the traces from different CPUs. It is possible to have a perf session where some events end up collecting the trace in TMC-ETR while the others in TRBE. Thus we need a way to identify the type of the trace for each AUX record. Define the trace formats exported by the CoreSight PMU. We don't define the flags following the "ETM" as this information is available to the user when issuing the session. What is missing is the additional formatting applied by the "sink" which is decided at the runtime and the user may not have a control on. So we define : - CORESIGHT format (indicates the Frame format) - RAW format (indicates the format of the source) The default value is CORESIGHT format for all the records (i,e == 0). Add the RAW format for others that use raw format. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Leach <mike.leach@linaro.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Leo Yan <leo.yan@linaro.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mike Leach <mike.leach@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20210405164307.1720226-3-suzuki.poulose@arm.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.