CoreSight June 2025

coresight@lists.linaro.org

9 participants
21 discussions

Re: [BUG] CoreSight: WARN_ON in coresight_disclaim_device_unlocked due to register reset on CPU power-cycle

by Suzuki K Poulose

Cc: coresight lists, Leo, James, Mike L Hello ! Thanks for the report ! In the future, please use scripts/get_maintainer.pl for the clear list of people/list for reporting issues. Response inline, below. On 20/06/2025 08:21, Keita Morisaki wrote: > Hello folks, > > I am writing to report a WARN_ON message I'm encountering in the > CoreSight driver on a multi-core ARM system running a 6.12-based kernel. > The warning appears consistently when disabling an Embedded Trace > Extension (ETE) source after it has been active. The issue is not > reproducible when CPUidle is disabled. > > The problem occurs because the driver assumes the CoreSight claim > register is persistent, but it could be reset by the CPUidle power > management flow. The section B2.3.2 of Arm CoreSight Architecture > Specification v3.0[1] indicates that the claim register must reset at > “reset”. A CPU power-up from an idle state can trigger a Cold reset, > which might explain this behavior. > > My ftrace analysis confirms this. I traced the only two functions that > modify the claim state: coresight_set_claim_tags (which sets the claim) > and coresight_clear_claim_tags (which is the only part of the kernel > that writes to CLAIMCLR). The trace shows the claim being set, followed > by a CPUidle transition, but no subsequent call to > coresight_clear_claim_tags. > > Here are the steps to reproduce the issue: > > modprobecoresight_etm4x > > # Enable any relevant sink > > echo1>/sys/bus/coresight/devices/ete0/enable_source > > echo0>/sys/bus/coresight/devices/ete0/enable_source > > > Here is a relevant snippet from the ftrace log that illustrates the > sequence: > > #tracer:function_graph > > # > > #CPUDURATIONFUNCTIONCALLS > > #||||||| > > 0)|coresight_claim_device_unlocked[coresight](){ > > 0)3.750us|coresight_set_claim_tags[coresight]();//Claimissethere > > 0)+20.260us|} > > 0)|/*psci_domain_idle_enter:cpu_id=0state={Our PSCI parameter value}*/// > CPUgoesidle > > 0)|/*psci_domain_idle_exit:cpu_id=0state={Our PSCI parameter value}*/// > CPUwakesup,causingColdreset > > ... > > 0)(a)309346.3us|coresight_disclaim_device_unlocked[coresight]();// > TriggersWARN_ON > > > The following WARN_ON [2] is printed because the CLAIMCLR register has > already been reset at the time coresight_disclaim_device_unlocked is > called, contrary to the driver's expectation. > We have the ETM driver performing the save/restore of ETM context during a CPUidle. This is only done when the ETM/ETE is described to be loosing context over PM operation. If this is not done (via DT), the driver doesn't do anything. This could be problematic. Could you try adding: "arm,coresight-loses-context-with-cpu" property to the ETE nodes and see if it makes a difference ? Kind regards Suzuki [0] https://elixir.bootlin.com/linux/v6.12/source/Documentation/devicetree/bind… > [416.354181][C0]WARNING:CPU:0PID:0atdrivers/hwtracing/coresight/ > coresight-core.c:187coresight_disclaim_device_unlocked+0x84/0x9c[coresight] > > [416.535454][C0]Calltrace: > > [416.538606][C0]coresight_disclaim_device_unlocked+0x84/0x9c[coresight] > > [416.549359][C0]etm4_disable_hw+0x2d8/0x374[coresight_etm4x] > > [416.623310][C0]do_idle+0x1d4/0x264 > > (Note on tracing: To get this detailed trace, I made two modifications > to the kernel. First, since the trace_psci_domain_idle_enter/exit events > are not available in kernel 6.12, I cherry-picked the upstream patch > 7b7644831e72 [3] to add them. Second, to specifically trace the claim > functions, I temporarily replaced their inline compiler hints with > noinline.) > > Given the evidence, it appears the driver's assumption that the claim > register is persistent across CPU power states is incorrect and may need > to be addressed. > > Could you please provide your guidance on this? > > Thank you for your time and assistance. > > [1] https://developer.arm.com/documentation/ihi0029/latest/ <https:// > developer.arm.com/documentation/ihi0029/latest/>_ > _[2] https://elixir.bootlin.com/linux/v6.12/source/drivers/hwtracing/ > coresight/coresight-core.c#L187 <https://elixir.bootlin.com/linux/v6.12/ > source/drivers/hwtracing/coresight/coresight-core.c#L187>_ > _[3] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/ > linux.git/commit/?id=7b7644831e7276f52a233ec685d13c965fff09d9 <https:// > web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/? > id=7b7644831e7276f52a233ec685d13c965fff09d9> > > Best regards, > Keita

1 week, 3 days

[PATCH v2 0/3] Coresight TMC-ETR some bugfixes and cleanups

by Junhao He

This patchset builds upon Yicong's previous patches [1]. Introducing fix two race issues found by using TMC-ETR and CATU, Two cleanups found when debugging the issues. [1] https://lore.kernel.org/linux-arm-kernel/20241202092419.11777-1-yangyicong@… --- Changes in v2: - Updated the commit of patch2. - Rebase to v6.16-rc1 Junhao He (1): coresight: tmc: refactor the tmc-etr mode setting to avoid race conditions Yicong Yang (2): coresight: tmc: Add missing doc of tmc_drvdata::reading coresight: tmc: Decouple the perf buffer allocation from sysfs mode .../hwtracing/coresight/coresight-tmc-etr.c | 102 +++++++++--------- drivers/hwtracing/coresight/coresight-tmc.h | 1 + 2 files changed, 53 insertions(+), 50 deletions(-) -- 2.33.0

1 week, 3 days

Re: [PATCH] coresight: Replace scnprintf() with sysfs_emit() in sysfs show functions

by James Clark

On 19/06/2025 4:07 pm, Chelsy Ratnawat wrote: > Replace calls to scnprintf() with sysfs_emit() in sysfs show functions. > These helpers are preferred in sysfs callbacks because they automatically > handle buffer sizing (PAGE_SIZE) and improve safety and readability. > > Signed-off-by: Chelsy Ratnawat <chelsyratnawat2001(a)gmail.com> > --- > .../hwtracing/coresight/coresight-etm-perf.c | 4 +- > .../coresight/coresight-etm3x-sysfs.c | 2 +- > .../coresight/coresight-etm4x-sysfs.c | 108 +++++++++--------- > drivers/hwtracing/coresight/coresight-stm.c | 8 +- There's two missing from coresight-sysfs.c. Might as well change those too while were here. With those changed: Reviewed-by: James Clark <james.clark(a)linaro.org>

1 week, 4 days

OpenCSD v1.6.1-rc1 release

by Mike Leach

A branch ocsd-main-v1.6.1-rc1 has been released on the OpenCSD github site This contains a number of bugfixes for issues relating to ETMv4 ETE speculative trace. See readme for further information. This has been released to allow for testing and feedback. Known issues outstanding: a) TINFO logging has minor issue on periodic TINFO elements. b) ETMv3 / PTM regression testss failing on return stack tests. Under investigation as this code is not part of the update. -- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK

1 week, 4 days

[PATCH 0/2] coresight: Dismiss smatch warnings

by Leo Yan

This series polishes the code to address warnings reported by the smatch static checker. Smatch reports a error "Function too hairy" for etm4x_sysreg_read() and etm4x_sysreg_write(). This is a trade off to avoid large code blocks, the implementation encapsulates logic using nested macros. But this is not friendly to static checker. For now, the code will be kept as is. Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- Leo Yan (2): coresight: stm: Remove redundant NULL checks coresight: perf: Use %px for printing pointers drivers/hwtracing/coresight/coresight-etm-perf.c | 4 ++-- drivers/hwtracing/coresight/coresight-stm.c | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-) --- base-commit: 408c97c4a5e0b634dcd15bf8b8808b382e888164 change-id: 20250611-arm_cs_fix_smatch_warning_v1-6c2b5e78e38a Best regards, -- Leo Yan <leo.yan(a)arm.com>

2 weeks, 4 days

Re: [PATCH v2] coresight: fix indentation error in cscfg_remove_owned_csdev_configs()

by Leo Yan

On Wed, Jun 11, 2025 at 11:30:25AM +0100, Yeoreum Yun wrote: > Fix wrong indentation in cscfg_remove_owned_csdev_configs() > > Reported-by: kernel test robot <lkp(a)intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202506102238.XQfScl5x-lkp@intel.com/ > Fixes: 53b9e2659719 ("coresight: holding cscfg_csdev_lock while removing cscfg from csdev") > Signed-off-by: Yeoreum Yun <yeoreum.yun(a)arm.com> Reviewed-by: Leo Yan <leo.yan(a)arm.com> > --- > > Sorry for my bad forgetting to run checkpatch.pl... > > --- > drivers/hwtracing/coresight/coresight-syscfg.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c > index 83dad24e0116..6836b05986e8 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c > @@ -395,7 +395,7 @@ static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, voi > if (list_empty(&csdev->config_csdev_list)) > return; > > - guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock); > + guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock); > > list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) { > if (config_csdev->config_desc->load_owner == load_owner) > -- > LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7} >

2 weeks, 5 days

[PATCH v9 0/2] coresight: Add Coresight Trace Network On Chip driver

by Yuanfang Zhang

The Trace Network On Chip (TNOC) is an integration hierarchy which is a hardware component that integrates the functionalities of TPDA and funnels. It collects trace from subsystems and transfers it to coresight sink. In addition to the generic TNOC mentioned above, there is also a special type of TNOC called Interconnect TNOC. Unlike the generic TNOC, the Interconnect TNOC doesn't need ATID. Its primary function is to connect the source of subsystems to the Aggregator TNOC. Its driver is different from this patch and will describe it and upstream its driver separately. Signed-off-by: Yuanfang Zhang <quic_yuanfang(a)quicinc.com> --- Changes in v9: - Mention the binding is only for Aggregator TNOC. - Link to v8: https://lore.kernel.org/r/20250606-trace-noc-v8-0-833f94712c57@quicinc.com Changes in v8: - Add sysfs node to expose atid. - Link to v7: https://lore.kernel.org/r/20250523-trace-noc-v7-0-d65edbab2997@quicinc.com Changes in v7: - Move the content in header file into coresight-tnoc.c. - Use scoped_guard() to replace spin_lock(). - Invoke coresight_trace_id_put_system_id() for registration failure. - Link to v6: https://lore.kernel.org/r/20250522-trace-noc-v6-0-f5a9bcae90ee@quicinc.com Changes in v6: - Add a newline after return statements. - Use 'x &= foo' to replace 'x = x & foo'. - Use 'x |= foo' to replace 'x = x | foo'. - Link to v5: https://lore.kernel.org/r/20250512-trace-noc-v5-0-f2ef070baee5@quicinc.com Changes in v5: - update cover-letter to describe the Interconnect TNOC. - Link to v4: https://lore.kernel.org/r/20250415-trace-noc-v4-0-979938fedfd8@quicinc.com Changes in v4: - Fix dt_binding warning. - update mask of trace_noc amba_id. - Modify driver comments. - rename TRACE_NOC_SYN_VAL to TRACE_NOC_SYNC_INTERVAL. - Link to v3: https://lore.kernel.org/r/20250411-trace-noc-v3-0-1f19ddf7699b@quicinc.com Changes in v3: - Remove unnecessary sysfs nodes. - update commit messages. - Use 'writel' instead of 'write_relaxed' when writing to the register for the last time. - Add trace_id ops. - Link to v2: https://lore.kernel.org/r/20250226-trace-noc-driver-v2-0-8afc6584afc5@quici… Changes in v2: - Modified the format of DT binging file. - Fix compile warnings. - Link to v1: https://lore.kernel.org/r/46643089-b88d-49dc-be05-7bf0bb21f847@quicinc.com --- Yuanfang Zhang (2): dt-bindings: arm: Add device Trace Network On Chip definition coresight: add coresight Trace Network On Chip driver .../bindings/arm/qcom,coresight-tnoc.yaml | 113 ++++++++++ drivers/hwtracing/coresight/Kconfig | 13 ++ drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tnoc.c | 242 +++++++++++++++++++++ 4 files changed, 369 insertions(+) --- base-commit: a2cc6ff5ec8f91bc463fd3b0c26b61166a07eb11 change-id: 20250403-trace-noc-f8286b30408e Best regards, -- Yuanfang Zhang <quic_yuanfang(a)quicinc.com>

2 weeks, 5 days

[PATCH v10 0/2] coresight: Add Coresight Trace Network On Chip driver

by Yuanfang Zhang

The Trace Network On Chip (TNOC) is an integration hierarchy which is a hardware component that integrates the functionalities of TPDA and funnels. It collects trace from subsystems and transfers it to coresight sink. In addition to the generic TNOC mentioned above, there is also a special type of TNOC called Interconnect TNOC. Unlike the generic TNOC, the Interconnect TNOC doesn't need ATID. Its primary function is to connect the source of subsystems to the Aggregator TNOC. Its driver is different from this patch and will describe it and upstream its driver separately. Signed-off-by: Yuanfang Zhang <quic_yuanfang(a)quicinc.com> --- Changes in v10: - Rebase to coresight/next branch. - Link to v9: https://lore.kernel.org/r/20250611-trace-noc-v9-0-4322d4cf8f4b@quicinc.com Changes in v9: - Mention the binding is only for Aggregator TNOC. - Link to v8: https://lore.kernel.org/r/20250606-trace-noc-v8-0-833f94712c57@quicinc.com Changes in v8: - Add sysfs node to expose atid. - Link to v7: https://lore.kernel.org/r/20250523-trace-noc-v7-0-d65edbab2997@quicinc.com Changes in v7: - Move the content in header file into coresight-tnoc.c. - Use scoped_guard() to replace spin_lock(). - Invoke coresight_trace_id_put_system_id() for registration failure. - Link to v6: https://lore.kernel.org/r/20250522-trace-noc-v6-0-f5a9bcae90ee@quicinc.com Changes in v6: - Add a newline after return statements. - Use 'x &= foo' to replace 'x = x & foo'. - Use 'x |= foo' to replace 'x = x | foo'. - Link to v5: https://lore.kernel.org/r/20250512-trace-noc-v5-0-f2ef070baee5@quicinc.com Changes in v5: - update cover-letter to describe the Interconnect TNOC. - Link to v4: https://lore.kernel.org/r/20250415-trace-noc-v4-0-979938fedfd8@quicinc.com Changes in v4: - Fix dt_binding warning. - update mask of trace_noc amba_id. - Modify driver comments. - rename TRACE_NOC_SYN_VAL to TRACE_NOC_SYNC_INTERVAL. - Link to v3: https://lore.kernel.org/r/20250411-trace-noc-v3-0-1f19ddf7699b@quicinc.com Changes in v3: - Remove unnecessary sysfs nodes. - update commit messages. - Use 'writel' instead of 'write_relaxed' when writing to the register for the last time. - Add trace_id ops. - Link to v2: https://lore.kernel.org/r/20250226-trace-noc-driver-v2-0-8afc6584afc5@quici… Changes in v2: - Modified the format of DT binging file. - Fix compile warnings. - Link to v1: https://lore.kernel.org/r/46643089-b88d-49dc-be05-7bf0bb21f847@quicinc.com --- Yuanfang Zhang (2): dt-bindings: arm: Add device Trace Network On Chip definition coresight: add coresight Trace Network On Chip driver .../bindings/arm/qcom,coresight-tnoc.yaml | 113 ++++++++++ drivers/hwtracing/coresight/Kconfig | 12 + drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tnoc.c | 242 +++++++++++++++++++++ 4 files changed, 368 insertions(+) --- base-commit: 408c97c4a5e0b634dcd15bf8b8808b382e888164 change-id: 20250403-trace-noc-f8286b30408e Best regards, -- Yuanfang Zhang <quic_yuanfang(a)quicinc.com>

2 weeks, 5 days

[PATCH] coresight: trbe: Add ISB after TRBLIMITR write

by James Clark

DEN0154 states that hardware will be allowed to ignore writes to TRB* registers while the trace buffer is enabled. Add an ISB to ensure that it's disabled before clearing the other registers. This is purely defensive because it's expected that arm_trbe_disable() would be called before teardown which has the required ISB. Fixes: a2b579c41fe9 ("coresight: trbe: Remove redundant disable call") Signed-off-by: James Clark <james.clark(a)linaro.org> --- drivers/hwtracing/coresight/coresight-trbe.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 8267dd1a2130..10f3fb401edf 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -257,6 +257,7 @@ static void trbe_drain_and_disable_local(struct trbe_cpudata *cpudata) static void trbe_reset_local(struct trbe_cpudata *cpudata) { write_sysreg_s(0, SYS_TRBLIMITR_EL1); + isb(); trbe_drain_buffer(); write_sysreg_s(0, SYS_TRBPTR_EL1); write_sysreg_s(0, SYS_TRBBASER_EL1); --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20250609-james-cs-trblimitr-isb-523f20d874d6 Best regards, -- James Clark <james.clark(a)linaro.org>

2 weeks, 6 days

[PATCH v8 0/2] coresight: Add Coresight Trace Network On Chip driver

by Yuanfang Zhang

The Trace Network On Chip (TNOC) is an integration hierarchy which is a hardware component that integrates the functionalities of TPDA and funnels. It collects trace from subsystems and transfers it to coresight sink. In addition to the generic TNOC mentioned above, there is also a special type of TNOC called Interconnect TNOC. Unlike the generic TNOC, the Interconnect TNOC doesn't need ATID. Its primary function is to connect the source of subsystems to the Aggregator TNOC. Its driver is different from this patch and will describe it and upstream its driver separately. Signed-off-by: Yuanfang Zhang <quic_yuanfang(a)quicinc.com> --- Changes in v8: - Add sysfs node to expose atid. - Link to v7: https://lore.kernel.org/r/20250523-trace-noc-v7-0-d65edbab2997@quicinc.com Changes in v7: - Move the content in header file into coresight-tnoc.c. - Use scoped_guard() to replace spin_lock(). - Invoke coresight_trace_id_put_system_id() for registration failure. - Link to v6: https://lore.kernel.org/r/20250522-trace-noc-v6-0-f5a9bcae90ee@quicinc.com Changes in v6: - Add a newline after return statements. - Use 'x &= foo' to replace 'x = x & foo'. - Use 'x |= foo' to replace 'x = x | foo'. - Link to v5: https://lore.kernel.org/r/20250512-trace-noc-v5-0-f2ef070baee5@quicinc.com Changes in v5: - update cover-letter to describe the Interconnect TNOC. - Link to v4: https://lore.kernel.org/r/20250415-trace-noc-v4-0-979938fedfd8@quicinc.com Changes in v4: - Fix dt_binding warning. - update mask of trace_noc amba_id. - Modify driver comments. - rename TRACE_NOC_SYN_VAL to TRACE_NOC_SYNC_INTERVAL. - Link to v3: https://lore.kernel.org/r/20250411-trace-noc-v3-0-1f19ddf7699b@quicinc.com Changes in v3: - Remove unnecessary sysfs nodes. - update commit messages. - Use 'writel' instead of 'write_relaxed' when writing to the register for the last time. - Add trace_id ops. - Link to v2: https://lore.kernel.org/r/20250226-trace-noc-driver-v2-0-8afc6584afc5@quici… Changes in v2: - Modified the format of DT binging file. - Fix compile warnings. - Link to v1: https://lore.kernel.org/r/46643089-b88d-49dc-be05-7bf0bb21f847@quicinc.com --- Yuanfang Zhang (2): dt-bindings: arm: Add device Trace Network On Chip definition coresight: add coresight Trace Network On Chip driver .../bindings/arm/qcom,coresight-tnoc.yaml | 111 ++++++++++ drivers/hwtracing/coresight/Kconfig | 13 ++ drivers/hwtracing/coresight/Makefile | 1 + drivers/hwtracing/coresight/coresight-tnoc.c | 242 +++++++++++++++++++++ 4 files changed, 367 insertions(+) --- base-commit: a2cc6ff5ec8f91bc463fd3b0c26b61166a07eb11 change-id: 20250403-trace-noc-f8286b30408e Best regards, -- Yuanfang Zhang <quic_yuanfang(a)quicinc.com>

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CoreSight June 2025