[PATCH v4 0/2] perf: arm/arm64: Improve completeness for kernel address space

[Leo Yan]

This patch set is to improve completeness for kernel address space for
arm/arm64; it adds architecture specific tweaking for the kernel start
address, thus can include the memory regions which are prior to '_stext'
symbol.  With this change, we can see the eBPF program can be parsed
properly on arm64.

This patch set is a following up version for the old patch "perf cs-etm:
Improve completeness for kernel address space" [1]; the old patch was
only to fix the issue for CoreSight ETM event; but the kernel address space
issue is not only limited to CoreSight event, it should be a common issue
for other events (e.g. PMU events), clock events for profiling eBPF
program.  So this patch set tries to resolve it as a common issue for
arm/arm64 archs.

When implemented related code, I tried to use the API
machine__create_extra_kernel_maps(); but I found the 'perf script' tool
directly calls machine__get_kernel_start() instead of running into
the flow for machine__create_extra_kernel_maps(); this is the reason I
don't use machine__create_extra_kernel_maps() for tweaking kernel start
address and refactor machine__get_kernel_start() alternatively.

If there have better method to resolve this issue, any suggestions and
comments are very welcome!

[1] https://lkml.org/lkml/2019/6/19/1057


Leo Yan (2):
  perf machine: Support arch's specific kernel start address
  perf machine: arm/arm64: Improve completeness for kernel address space

 tools/perf/Makefile.config           | 22 ++++++++++++++++++++++
 tools/perf/arch/arm/util/Build       |  2 ++
 tools/perf/arch/arm/util/machine.c   | 17 +++++++++++++++++
 tools/perf/arch/arm64/util/Build     |  1 +
 tools/perf/arch/arm64/util/machine.c | 17 +++++++++++++++++
 tools/perf/arch/x86/util/machine.c   | 10 ++++++++++
 tools/perf/util/machine.c            | 13 +++++++------
 tools/perf/util/machine.h            |  2 ++
 8 files changed, 78 insertions(+), 6 deletions(-)
 create mode 100644 tools/perf/arch/arm/util/machine.c
 create mode 100644 tools/perf/arch/arm64/util/machine.c

-- 
2.17.1