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Message-ID: <20240916111659.GA716806@hyd1403.caveonetworks.com>
Date: Mon, 16 Sep 2024 16:46:59 +0530
From: Linu Cherian <lcherian@...vell.com>
To: <suzuki.poulose@....com>, <mike.leach@...aro.org>, <james.clark@....com>
CC: <linux-arm-kernel@...ts.infradead.org>, <coresight@...ts.linaro.org>,
<linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
<corbet@....net>, <devicetree@...r.kernel.org>, <sgoutham@...vell.com>,
<gcherian@...vell.com>
Subject: Re: [PATCH v10 0/8] Coresight for Kernel panic and watchdog reset
Hi,
On 2024-09-16 at 16:04:29, Linu Cherian (lcherian@...vell.com) wrote:
> This patch series is rebased on coresight-next-v6.12.
Adding info which i missed out in the cover letter.
* V9 was posted here,
https://lore.kernel.org/linux-arm-kernel/20240605081725.622953-1-lcherian@marvell.com/
* Patches 1 & 2 adds support for allocation of trace buffer pages from reserved RAM
* Patches 3 & 4 adds support for saving metadata at the time of kernel panic
* Patch 5 adds support for reading trace data captured at the time of panic
* Patches 6 & 7 adds support for disabling coresight blocks at the time of panic
* Patch 8: Gives the full description about this feature as part of
documentation
>
> Changelog from v9:
> * Add common helper function of_tmc_get_reserved_resource_by_name
> for better code reuse
> * Reserved buffer validity and crashdata validity has been separated to
> avoid interdependence
> * New fields added to crash metadata: version, ffcr, ffsr, mode
> * Version checks added for metadata validation
> * Special file /dev/crash_tmc_xxx would be available only when
> crash metadata is valid
> * Removed READ_CRASHDATA mode meant for special casing crashdata reads.
> Instead, dedicated read function added for crashdata reads from reserved
> buffer which is common for both ETR and ETF sinks as well.
> * Documentation added to Documentation/tracing/coresight/panic.rst
>
> Changelog from v8:
> * Added missing exit path on error in __tmc_probe.
> * Few whitespace fixes, checkpatch fixes.
> * With perf sessions honouring stop_on_flush sysfs attribute,
> removed redundant variable stop_on_flush_en.
>
> Changelog from v7:
> * Fixed breakage on perf test -vvvv "arm coresight".
> No issues seen with and without "resrv" buffer mode
> * Moved the crashdev registration into a separate function.
> * Removed redundant variable in tmc_etr_setup_crashdata_buf
> * Avoided a redundant memcpy in tmc_panic_sync_etf.
> * Tested kernel panic with trace session started uisng perf.
> Please see the title "Perf based testing" below for details.
> For this, stop_on_flush sysfs attribute is taken into
> consideration while starting perf sessions as well.
>
> Changelog from v6:
> * Added special device files for reading crashdata, so that
> read_prevboot mode flag is removed.
> * Added new sysfs TMC device attribute, stop_on_flush.
> Stop on flush trigger event is disabled by default.
> User need to explicitly enable this from sysfs for panic stop
> to work.
> * Address parameter for panicstop ETM configuration is
> chosen as kernel "panic" address by default.
> * Added missing tmc_wait_for_tmcready during panic handling
> * Few other misc code rearrangements.
>
> Changelog from v5:
> * Fixed issues reported by CONFIG_DEBUG_ATOMIC_SLEEP
> * Fixed a memory leak while reading data from /dev/tmc_etrx in
> READ_PREVBOOT mode
> * Tested reading trace data from crashdump kernel
>
> Changelog from v4:
> * Device tree binding
> - Description is made more explicit on the usage of reserved memory
> region
> - Mismatch in memory region names in dts binding and driver fixed
> - Removed "mem" suffix from the memory region names
> * Rename "struct tmc_register_snapshot" -> "struct tmc_crash_metadata",
> since it contains more than register snapshot.
> Related variables are named accordingly.
> * Rename struct tmc_drvdata members
> resrv_buf -> crash_tbuf
> metadata -> crash_mdata
> * Size field in metadata refers to RSZ register and hence indicates the
> size in 32 bit words. ETR metadata follows this convention, the same
> has been extended to ETF metadata as well.
> * Added crc32 for more robust metadata and tracedata validation.
> * Added/modified dev_dbg messages during metadata validation
> * Fixed a typo in patch 5 commit description
>
> Changelog from v3:
> * Converted the Coresight ETM driver change to a named configuration.
> RFC tag has been removed with this change.
> * Fixed yaml issues reported by "make dt_binding_check"
> * Added names for reserved memory regions 0 and 1
> * Added prevalidation checks for metadata processing
> * Fixed a regression introduced in RFC v3
> - TMC Status register was getting saved wrongly
> * Reverted memremap attribute changes from _WB to _WC to match
> with the dma map attributes
> * Introduced reserved buffer mode specific .sync op.
> This fixes a possible crash when reserved buffer mode was used in
> normal trace capture, due to unwanted dma maintenance operations.
>
> *** SUBJECT HERE ***
>
> *** BLURB HERE ***
Sorry about this.
>
> Linu Cherian (8):
> dt-bindings: arm: coresight-tmc: Add "memory-region" property
> coresight: tmc-etr: Add support to use reserved trace memory
> coresight: core: Add provision for panic callbacks
> coresight: tmc: Enable panic sync handling
> coresight: tmc: Add support for reading crash data
> coresight: tmc: Stop trace capture on FlIn
> coresight: config: Add preloaded configuration
> Documentation: coresight: Panic support
>
> .../bindings/arm/arm,coresight-tmc.yaml | 26 ++
> Documentation/trace/coresight/panic.rst | 356 ++++++++++++++++++
> drivers/hwtracing/coresight/Makefile | 2 +-
> .../coresight/coresight-cfg-preload.c | 2 +
> .../coresight/coresight-cfg-preload.h | 2 +
> .../hwtracing/coresight/coresight-cfg-pstop.c | 83 ++++
> drivers/hwtracing/coresight/coresight-core.c | 42 +++
> .../hwtracing/coresight/coresight-tmc-core.c | 296 ++++++++++++++-
> .../hwtracing/coresight/coresight-tmc-etf.c | 124 +++++-
> .../hwtracing/coresight/coresight-tmc-etr.c | 231 +++++++++++-
> drivers/hwtracing/coresight/coresight-tmc.h | 106 ++++++
> include/linux/coresight.h | 24 ++
> 12 files changed, 1282 insertions(+), 12 deletions(-)
> create mode 100644 Documentation/trace/coresight/panic.rst
> create mode 100644 drivers/hwtracing/coresight/coresight-cfg-pstop.c
>
> --
> 2.34.1
>
Linu Cherian.
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