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The low level index of raw branch records for the most recent branch can be recorded in a sample with PERF_SAMPLE_BRANCH_HW_INDEX branch_sample_type. Extend struct branch_stack to support it. However, if the PERF_SAMPLE_BRANCH_HW_INDEX is not applied, only nr and entries[] will be output by kernel. The pointer of entries[] could be wrong, since the output format is different with new struct branch_stack. Add a variable no_hw_idx in struct perf_sample to indicate whether the hw_idx is output. Add get_branch_entry() to return corresponding pointer of entries[0]. To make dummy branch sample consistent as new branch sample, add hw_idx in struct dummy_branch_stack for cs-etm and intel-pt. Apply the new struct branch_stack for synthetic events as well. Extend test case sample-parsing to support new struct branch_stack. Committer notes: Renamed get_branch_entries() to perf_sample__branch_entries() to have proper namespacing and pave the way for this to be moved to libperf, eventually. Add 'static' to that inline as it is in a header. Add 'hw_idx' to 'struct dummy_branch_stack' in cs-etm.c to fix the build on arm64. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Pavel Gerasimov <pavel.gerasimov@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Stephane Eranian <eranian@google.com> Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com> Link: http://lore.kernel.org/lkml/20200228163011.19358-2-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.