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* [PATCH v2 0/5] fix inconsistencies with sysfs configuration in etmX
@ 2026-04-10  7:43 Yeoreum Yun
  2026-04-10  7:43 ` [PATCH v2 1/5] coresight: etm4x: introduce struct etm4_caps Yeoreum Yun
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Yeoreum Yun @ 2026-04-10  7:43 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, Yeoreum Yun

The current ETMx configuration via sysfs can lead to the following
inconsistencies:

  - If a configuration is modified via sysfs while a perf session is
    active, the running configuration may differ between before
    a sched-out and after a subsequent sched-in.

  - If a perf session and sysfs session tries to enable concurrently,
    configuration from configfs could be corrupted (etm4).

  - There is chance to corrupt drvdata->config if perf session tries
    to enabled among handling cscfg_csdev_disable_active_config()
    in etm4_disable_sysfs() (etm4).

To resolve these inconsistencies, the configuration should be separated into:

  - active_config, which is applied configuration for the current session
  - config, which stores the settings configured via sysfs.

and apply configuration from configfs after taking a mode.


This patch based on v7.0-rc7


Patch History
=============

from v1 to v2
  - rebased to v7.0-rc7.
  - introduce etmX_caps structure to save etmX's capabilities.
  - remove ss_status from etmv4_config.
  - modify active_config after taking a mode (perf/sysfs).
  - https://lore.kernel.org/all/20260317181705.2456271-1-yeoreum.yun@arm.com/

Yeoreum Yun (5):
  coresight: etm4x: introduce struct etm4_caps
  coresight: etm4x: exclude ss_status from drvdata->config
  coresight: etm4x: fix inconsistencies with sysfs configration
  coresight: etm3x: introduce struct etm_caps
  coresight: etm3x: fix inconsistencies with sysfs configration

 drivers/hwtracing/coresight/coresight-etm.h   |  42 ++-
 .../coresight/coresight-etm3x-core.c          |  53 +--
 .../coresight/coresight-etm3x-sysfs.c         |  14 +-
 .../hwtracing/coresight/coresight-etm4x-cfg.c |   3 +-
 .../coresight/coresight-etm4x-core.c          | 322 ++++++++++--------
 .../coresight/coresight-etm4x-sysfs.c         | 192 ++++++-----
 drivers/hwtracing/coresight/coresight-etm4x.h | 180 +++++-----
 7 files changed, 450 insertions(+), 356 deletions(-)


base-commit: 591cd656a1bf5ea94a222af5ef2ee76df029c1d2
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



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2026-04-10  7:43 [PATCH v2 0/5] fix inconsistencies with sysfs configuration in etmX Yeoreum Yun
2026-04-10  7:43 ` [PATCH v2 1/5] coresight: etm4x: introduce struct etm4_caps Yeoreum Yun
2026-04-10  7:43 ` [PATCH v2 2/5] coresight: etm4x: exclude ss_status from drvdata->config Yeoreum Yun
2026-04-10  7:43 ` [PATCH v2 3/5] coresight: etm4x: fix inconsistencies with sysfs configration Yeoreum Yun
2026-04-10  7:43 ` [PATCH v2 4/5] coresight: etm3x: introduce struct etm_caps Yeoreum Yun
2026-04-10  7:43 ` [PATCH v2 5/5] coresight: etm3x: fix inconsistencies with sysfs configration Yeoreum Yun

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