[PATCH v4 0/7] coresight: Pulse an ETM external output for a PMU event

[Amir Ayupov <aaupov@fb.com>]

Add an ETMv4 configuration, pmu_pulse, that drives trace unit external
output 1 on every traced cycle, so a PMU event counting it (TRCEXTOUT1)
can end a fixed-length ETM window, for example with aux-action=pause.
The feature only loads on an ETE whose PMU counts its external outputs.

Patch 1 is Leo's fix for TRCIDR0.NUMEVENT decoding, which patch 6 relies
on for the number of external outputs.

Changes in v4:
- Fix the arm64 build: v3 defined pmuv3_event_implemented() in
  linux/perf/arm_pmuv3.h after including asm/arm_pmuv3.h, which broke
  files that include asm/arm_pmuv3.h directly, such as
  arch/arm64/kernel/cpufeature.c. Move it to the arm64 asm/arm_pmuv3.h,
  after the helpers it uses.
  Breakage reported by kernel test robot.
- Link to v3: https://lore.kernel.org/r/cover.1792907332.git.aaupov@fb.com

Changes in v3:
- Rebase onto coresight next, which moves the capability fields into
  drvdata->caps (Leo).
- Carry Leo's "coresight: etm4x: Fix event count decoding" (Leo).
- Add Leo's Reviewed-by to "Fail to enable a configuration not loaded on
  the device".
- Define CS_CFG_MATCH_CLASS_MASK and CS_CFG_MATCH_CAP_MASK with
  GENMASK_U32() and split the match check into early returns (Leo). The
  class check stays an intersection, as ETMv4 devices register with
  SRC_ALL | SRC_ETM4 while the built-in features only set SRC_ETM4.
- Remove the unused CS_CFG_MATCH_INST_ANY in a separate patch (Leo).
- Replace the per-output CS_CFG_MATCH_CAP_PMU_EXTOUT(n) bits with a single
  CS_CFG_MATCH_CAP_TRCEXTOUT, set on ETE only (Leo, James).
- Check the PMU events through a new pmuv3_event_implemented() helper
  instead of open-coding PMCEID0_EL0 in etm4x (James).
- Use PMU-agnostic event names in the documentation example (Daniel).
- Add Daniel's Reviewed-by to "Add pmu_pulse/extout_pulse".
- Link to v2: https://lore.kernel.org/r/20261012230527.750567-1-aaupov@fb.com

Amir Ayupov (6):
  coresight: syscfg: Fail to enable a configuration not loaded on the
    device
  coresight: syscfg: Match feature capabilities separately from device
    class
  coresight: syscfg: Remove unused CS_CFG_MATCH_INST_ANY
  perf: arm_pmuv3: Add pmuv3_event_implemented()
  coresight: etm4x: Report whether the PMU counts the external outputs
  coresight: Add pmu_pulse/extout_pulse

Leo Yan (1):
  coresight: etm4x: Fix event count decoding

 .../trace/coresight/coresight-config.rst      |  5 ++
 .../trace/coresight/coresight-perf.rst        | 15 ++++
 arch/arm64/include/asm/arm_pmuv3.h            | 19 ++++
 drivers/hwtracing/coresight/Makefile          |  1 +
 .../coresight/coresight-cfg-pmu-pulse.c       | 55 ++++++++++++
 .../coresight/coresight-cfg-preload.c         |  2 +
 .../coresight/coresight-cfg-preload.h         |  2 +
 .../hwtracing/coresight/coresight-config.h    | 11 ++-
 .../hwtracing/coresight/coresight-etm4x-cfg.c |  6 +-
 .../coresight/coresight-etm4x-core.c          | 39 +++++++-
 .../coresight/coresight-etm4x-sysfs.c         | 29 +++---
 drivers/hwtracing/coresight/coresight-etm4x.h |  3 +
 .../coresight/coresight-syscfg-configfs.c     |  3 +
 .../hwtracing/coresight/coresight-syscfg.c    | 90 +++++++++++--------
 include/linux/perf/arm_pmu.h                  |  1 -
 include/linux/perf/arm_pmuv3.h                |  3 +
 16 files changed, 229 insertions(+), 55 deletions(-)
 create mode 100644 drivers/hwtracing/coresight/coresight-cfg-pmu-pulse.c


base-commit: 343cfcbb3ecfdb80aa576a428cfa3b65ad783842
-- 
2.52.0