linux-kernel - Re: [PATCH v2 0/9] coresight: change some driver' spinlock type to raw_spinlock

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Message-ID: <CAJ9a7Vis9vcdJOzu9tvNQ4eAacmXkbhbZBaRYd1acOrd8G-ZUQ@mail.gmail.com>
Date: Wed, 18 Dec 2024 13:44:41 +0000
From: Mike Leach <mike.leach@...aro.org>
To: Yeoreum Yun <yeoreum.yun@....com>
Cc: suzuki.poulose@....com, james.clark@...aro.org, 
	alexander.shishkin@...ux.intel.com, bigeasy@...utronix.de, 
	clrkwllms@...nel.org, rostedt@...dmis.org, coresight@...ts.linaro.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-rt-devel@...ts.linux.dev, nd@....com
Subject: Re: [PATCH v2 0/9] coresight: change some driver' spinlock type to raw_spinlock_t

This change seems to omit devices:

etm3x - which provides support for ETMv3 and PTM, both of which are
valid trace sources in the cs_etm handling code.
stm - can be integrated into the kernel STM via configfs providing a
MIPI source for ftrace.

Mike

On Tue, 3 Dec 2024 at 11:49, Yeoreum Yun <yeoreum.yun@....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@...aro.org>
>
> v1 to v2:
>     - seperate patchsets to change locktype and apply gurad API.
>
> Levi 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    |  21 +-
>  .../hwtracing/coresight/coresight-config.h    |   2 +-
>  drivers/hwtracing/coresight/coresight-core.c  |   2 +-
>  .../hwtracing/coresight/coresight-cti-core.c  |  65 +-
>  .../hwtracing/coresight/coresight-cti-sysfs.c | 135 +++--
>  drivers/hwtracing/coresight/coresight-cti.h   |   2 +-
>  drivers/hwtracing/coresight/coresight-etb10.c |  62 +-
>  .../coresight/coresight-etm4x-core.c          |  71 ++-
>  .../coresight/coresight-etm4x-sysfs.c         | 566 +++++++++---------
>  drivers/hwtracing/coresight/coresight-etm4x.h |   2 +-
>  .../hwtracing/coresight/coresight-funnel.c    |  34 +-
>  .../coresight/coresight-replicator.c          |  36 +-
>  .../hwtracing/coresight/coresight-syscfg.c    |  75 ++-
>  .../hwtracing/coresight/coresight-tmc-core.c  |   9 +-
>  .../hwtracing/coresight/coresight-tmc-etf.c   | 195 +++---
>  .../hwtracing/coresight/coresight-tmc-etr.c   | 199 +++---
>  drivers/hwtracing/coresight/coresight-tmc.h   |   2 +-
>  .../hwtracing/coresight/coresight-trace-id.c  |  93 ++-
>  drivers/hwtracing/coresight/ultrasoc-smb.c    |  12 +-
>  drivers/hwtracing/coresight/ultrasoc-smb.h    |   2 +-
>  include/linux/coresight.h                     |   4 +-
>  21 files changed, 751 insertions(+), 838 deletions(-)
>
> --
> LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
>


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