[RFC 0/4] perf: Per PMU access controls (paranoid setting)

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>

For situations where sysadmins might want to allow different level of
access control for different PMUs, we start creating per-PMU
perf_event_paranoid controls in sysfs.

These work in equivalent fashion as the existing perf_event_paranoid
sysctl, which now becomes the parent control for each PMU.

On PMU registration the global/parent value will be inherited by each PMU,
as it will be propagated to all registered PMUs when the sysctl is
updated.

At any later point individual PMU access controls, located in
<sysfs>/device/<pmu-name>/perf_event_paranoid, can be adjusted to achieve
fine grained access control.

Discussion from previous posting:
https://lkml.org/lkml/2018/5/21/156

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx

Tvrtko Ursulin (4):
  perf: Move some access checks later in perf_event_open
  perf: Pass pmu pointer to perf_paranoid_* helpers
  perf: Allow per PMU access control
  perf Documentation: Document the per PMU perf_event_paranoid interface

 .../sysfs-bus-event_source-devices-events     |  14 +++
 arch/powerpc/perf/core-book3s.c               |   2 +-
 arch/x86/events/intel/bts.c                   |   2 +-
 arch/x86/events/intel/core.c                  |   2 +-
 arch/x86/events/intel/p4.c                    |   2 +-
 include/linux/perf_event.h                    |  18 ++-
 kernel/events/core.c                          | 104 +++++++++++++++---
 kernel/sysctl.c                               |   4 +-
 kernel/trace/trace_event_perf.c               |   6 +-
 9 files changed, 123 insertions(+), 31 deletions(-)

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2.17.1