Re: [PATCH v3 0/9] coresight: change some driver' spinlock type to raw_spinlock_t

[Yeoreum Yun <yeoreum.yun@arm.com>]

Hi Mike,

> Hi,
>
> On Mon, 16 Dec 2024 at 11:50, Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> >
> > In some coresight drivers, drvdata->spinlock can be held during __schedule()
> > by perf_event_task_sched_out()/in().
> >
> > Since drvdata->spinlock type is spinlock_t and
> > perf_event_task_sched_out()/in() is called after acquiring rq_lock,
> > which is raw_spinlock_t (an unsleepable lock),
> > this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.
> >
> > To address this,change type drvdata->spinlock in some coresight drivers,
> > which can be called by perf_event_task_sched_out()/in(),
> > from spinlock_t to raw_spinlock_t.
> >
> > Reviewed-by: James Clark <james.clark@linaro.org>
> >
> > v2 to v3:
> >     - Fix build error
> >
> > v1 to v2:
> >     - seperate patchsets to change locktype and apply gurad API.
> >
> > Yeoreum Yun (9):
> >   coresight: change coresight_device lock type to  raw_spinlock_t
> >   coresight-etm4x: change etmv4_drvdata spinlock type to  raw_spinlock_t
> >   coresight: change coresight_trace_id_map's lock type to
> >     raw_spinlock_t
> >   coresight-cti: change cti_drvdata spinlock's type to raw_spinlock_t
> >   coresight-etb10: change etb_drvdata spinlock's type to raw_spinlock_t
> >   coresight-funnel: change funnel_drvdata spinlock's type to
> >     raw_spinlock_t
> >   coresight-replicator: change replicator_drvdata spinlock's type to
> >     raw_spinlock_t
> >   coresight-tmc: change tmc_drvdata spinlock's type to raw_spinlock_t
> >   coresight/ultrasoc: change cti_drvdata spinlock's type to
> >     raw_spinlock_t
> >
> >  .../hwtracing/coresight/coresight-config.c    |   8 +-
> >  .../hwtracing/coresight/coresight-config.h    |   2 +-
> >  drivers/hwtracing/coresight/coresight-core.c  |   2 +-
> >  .../hwtracing/coresight/coresight-cti-core.c  |  44 +--
> >  .../hwtracing/coresight/coresight-cti-sysfs.c |  76 +++---
> >  drivers/hwtracing/coresight/coresight-cti.h   |   2 +-
> >  drivers/hwtracing/coresight/coresight-etb10.c |  26 +-
> >  .../coresight/coresight-etm4x-core.c          |  18 +-
> >  .../coresight/coresight-etm4x-sysfs.c         | 250 +++++++++---------
> >  drivers/hwtracing/coresight/coresight-etm4x.h |   2 +-
> >  .../hwtracing/coresight/coresight-funnel.c    |  12 +-
> >  .../coresight/coresight-replicator.c          |  12 +-
> >  .../hwtracing/coresight/coresight-syscfg.c    |  26 +-
> >  .../hwtracing/coresight/coresight-tmc-core.c  |   6 +-
> >  .../hwtracing/coresight/coresight-tmc-etf.c   |  48 ++--
> >  .../hwtracing/coresight/coresight-tmc-etr.c   |  40 +--
> >  drivers/hwtracing/coresight/coresight-tmc.h   |   2 +-
> >  .../hwtracing/coresight/coresight-trace-id.c  |  22 +-
> >  drivers/hwtracing/coresight/ultrasoc-smb.c    |  12 +-
> >  drivers/hwtracing/coresight/ultrasoc-smb.h    |   2 +-
> >  include/linux/coresight.h                     |   4 +-
> >  21 files changed, 308 insertions(+), 308 deletions(-)
> >
> > --
> > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
> >
>
> Notably missing is the same changes for the etm3x driver. The ETMv3.x
> and PTM1.x are supported by this driver, and these trace source
> variants are also supported in perf in the cs_etm.c code.
>
> STM is also missing, though this is not directly enabled via perf -
> but could perhaps run concurrently as it can be a target output for
> ftrace.
>
> Regards

Thanks for review. okay I'll back with new patch set including etm3 /
stm.

Thanks!

> --
> Mike Leach
> Principal Engineer, ARM Ltd.
> Manchester Design Centre. UK