CoreSight

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4 participants
2736 discussions

Re: [PATCH] coresight: fix missing error code when trace ID is invalid

by Leo Yan

On Fri, May 08, 2026 at 01:45:35PM +0800, Jie Gan wrote: [...] > coresight_path_assign_trace_id(path, CS_MODE_SYSFS); > - if (!IS_VALID_CS_TRACE_ID(path->trace_id)) > + if (!IS_VALID_CS_TRACE_ID(path->trace_id)) { > + ret = -EINVAL; > goto err_path; > + } On the top of this patch, could we do a further improvement? Move IS_VALID_CS_TRACE_ID() into coresight_path_assign_trace_id() and return 0 for success and < 0 for failures. As result, callers only need to check the returned value. For this patch: Reviewed-by: Leo Yan <leo.yan(a)arm.com>

1 week, 4 days

Re: [PATCH v11 07/27] coresight: Take a reference on csdev

by Leo Yan

On Thu, May 07, 2026 at 03:55:26PM +0100, James Clark wrote: [...] > Hi Leo, > > Testing on the Orion O6 board was all good, and so was stress testing > concurrent sysfs mode and hotplug on Juno. Thanks a lot for test! > However, I was trying to stress test sysfs mode and rmmod on Juno and > ran into an issue, although a similar issue is present without your > patchset. I don't think CPU PM introduces additional complexity for the above cases. The reason is that CPU PM notifiers _only_ apply to active sessions, and once a device is enabled, the module cannot be removed. If the race conditions between enabling/disabling sessions and module load/unload are properly handled, CPU PM should be safe. If we have bug in these race conditions, the high frequency data access in CPU PM may expose the issues - I don't expect CPU PM is the culprit. > If you run an rmmod on all the coresight devices at the same time as an > enable_source / disable loop you always get this: > > WARNING: possible circular locking dependency detected > 7.0.0-rc1+ #713 Tainted: G N > ------------------------------------------------------ > rmmod/1361 is trying to acquire lock: > ffff0008042f69a8 (kn->active#144){++++}-{0:0}, at: > __kernfs_remove+0x1b8/0x2c8 kn->active is not a lock but an active reference of sysfs node, but it use lockdep annotation to detect lock dependency. > Possible unsafe locking scenario: > CPU0 CPU1 > ---- ---- > lock(coresight_mutex); > lock(cpu_hotplug_lock); > lock(coresight_mutex); > lock(kn->active#144); > *** DEADLOCK *** The potential deadlock sequence could be: kernfs_fop_write_iter() `> kernfs_get_active_of() => acquire kn->active `> coresight_enable_sysfs() => acquire coresight_mutex coresight_unregister() => acquire coresight_mutex `> device_unregister() `> __kernfs_remove() `> kernfs_drain() => acquire kn->active > I think the issue can be fixed by releasing the coresight_mutex before > device_unregister(): > > diff --git a/drivers/hwtracing/coresight/coresight-core.c > b/drivers/hwtracing/coresight/coresight-core.c > index 015363da12fa..620560880f12 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -1639,8 +1639,8 @@ void coresight_unregister(struct coresight_device > *csdev) > coresight_remove_conns(csdev); > coresight_clear_default_sink(csdev); > coresight_release_platform_data(csdev->dev.parent, csdev->pdata); > - device_unregister(&csdev->dev); > mutex_unlock(&coresight_mutex); > + device_unregister(&csdev->dev); > } > EXPORT_SYMBOL_GPL(coresight_unregister); If so, we also need to move device_register() out of the mutex scope. That said, I still think we should dive a bit if can use smaller locking granluarity (combining with bus management provided by device model). > Although I didn't think too hard about the implications, but it might be ok > because once all the connections are removed the device can't be used so > releasing the coresight_mutex isn't an issue. > > But then testing that I ran into some kind of refleak where I couldn't > unload modules anymore, even though I'd disabled everything. But that could > be a different issue: > > rmmod: ERROR: Module coresight_funnel is in use > rmmod: ERROR: Module coresight_replicator is in use > rmmod: ERROR: Module coresight_etm4x is in use > rmmod: ERROR: Module coresight_tmc is in use > rmmod: ERROR: Module coresight_cti is in use > rmmod: ERROR: Module coresight is in use by: coresight_tmc coresight_cti > coresight_etm4x coresight_replicator coresight_funnel I suspect this is due to module references are not properly released, or the entire CS path is not properly disabled. After the issue occurs, can the ETM sysfs knob still be accessed? I am curious whether this is caused by the sysfs knob disappearing so no way to disable the path or the sysfs knob still exists but the driver internally misses to disable the path. > Anyway I don't think your patches make this worse, so we can probably ignore > it, but it would be good to be able to stress test the new modifications > around the same area. As no regression in test, I agree that we should not defer this series. We can fix the race with module load/unload as a separate task: - sysfs mode + module load/unload - perf mode + module load/unload Then we can combine stress test with CPU idle/hotplug. Thanks, Leo

1 week, 4 days

Re: [PATCH v2] coresight: fix missing error code when trace ID is invalid

by James Clark

On 09/05/2026 1:58 am, Jie Gan wrote: > When coresight_path_assign_trace_id() cannot assign a valid trace ID, > coresight_enable_sysfs() takes the err_path goto with ret still 0, > returning success to the caller despite no trace session being started. > > Fix this by changing coresight_path_assign_trace_id() to return int. > Move the IS_VALID_CS_TRACE_ID() check inside the function so it returns > -EINVAL on failure and 0 on success. Update coresight_enable_sysfs() to > check the return value directly instead of inspecting path->trace_id > after the call. > > The other caller in coresight-etm-perf.c discards the return value and > continues to check path->trace_id via IS_VALID_CS_TRACE_ID() directly. > This is unaffected: on failure path->trace_id is no longer written, so > it remains 0, which IS_VALID_CS_TRACE_ID() rejects the same as before. > > Fixes: d87d76d823d1 ("Coresight: Allocate trace ID after building the path") > Signed-off-by: Jie Gan <jie.gan(a)oss.qualcomm.com> > --- > Changes in v2: > - Refactor the coresight_path_assign_trace_id function. > - Link to v1: https://lore.kernel.org/r/20260508-fix-trace-id-error-v1-1-5f11a5456fdf@oss… > --- > drivers/hwtracing/coresight/coresight-core.c | 14 ++++++++++---- > drivers/hwtracing/coresight/coresight-priv.h | 2 +- > drivers/hwtracing/coresight/coresight-sysfs.c | 4 ++-- > 3 files changed, 13 insertions(+), 7 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index 46f247f73cf6..cabdc0c72f38 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -739,12 +739,12 @@ static int coresight_get_trace_id(struct coresight_device *csdev, > * Call this after creating the path and before enabling it. This leaves > * the trace ID set on the path, or it remains 0 if it couldn't be assigned. > */ > -void coresight_path_assign_trace_id(struct coresight_path *path, > +int coresight_path_assign_trace_id(struct coresight_path *path, > enum cs_mode mode) > { > struct coresight_device *sink = coresight_get_sink(path); > struct coresight_node *nd; > - int trace_id; > + int trace_id, ret = -EINVAL; > > list_for_each_entry(nd, &path->path_list, link) { > /* Assign a trace ID to the path for the first device that wants to do it */ > @@ -755,10 +755,16 @@ void coresight_path_assign_trace_id(struct coresight_path *path, > * Non 0 is either success or fail. > */ > if (trace_id != 0) { > - path->trace_id = trace_id; > - return; > + if (IS_VALID_CS_TRACE_ID(trace_id)) { > + path->trace_id = trace_id; > + ret = 0; Reviewed-by: James Clark <james.clark(a)linaro.org> Minor nit, but just "return 0" here is a bit simpler. > + } > + > + return ret; And then "return -EINVAL" for these ones. > } > } > + > + return ret; > } > > /** > diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h > index 1ea882dffd70..34c7e792adbd 100644 > --- a/drivers/hwtracing/coresight/coresight-priv.h > +++ b/drivers/hwtracing/coresight/coresight-priv.h > @@ -153,7 +153,7 @@ int coresight_make_links(struct coresight_device *orig, > void coresight_remove_links(struct coresight_device *orig, > struct coresight_connection *conn); > u32 coresight_get_sink_id(struct coresight_device *csdev); > -void coresight_path_assign_trace_id(struct coresight_path *path, > +int coresight_path_assign_trace_id(struct coresight_path *path, > enum cs_mode mode); > > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X) > diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c > index d2a6ed8bcc74..b6a870399e83 100644 > --- a/drivers/hwtracing/coresight/coresight-sysfs.c > +++ b/drivers/hwtracing/coresight/coresight-sysfs.c > @@ -211,8 +211,8 @@ int coresight_enable_sysfs(struct coresight_device *csdev) > goto out; > } > > - coresight_path_assign_trace_id(path, CS_MODE_SYSFS); > - if (!IS_VALID_CS_TRACE_ID(path->trace_id)) > + ret = coresight_path_assign_trace_id(path, CS_MODE_SYSFS); > + if (ret) > goto err_path; > > ret = coresight_enable_path(path, CS_MODE_SYSFS); > > --- > base-commit: 17c7841d09ee7d33557fd075562d9289b6018c90 > change-id: 20260508-fix-trace-id-error-dbfdd4d8f2d1 > > Best regards,

1 week, 4 days

Re: [PATCH v6 04/13] coresight: etm4x: exclude ss_status from drvdata->config

by Leo Yan

On Wed, Apr 22, 2026 at 02:21:54PM +0100, Yeoreum Yun wrote: [...] > @@ -573,11 +573,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) > etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i)); > > for (i = 0; i < caps->nr_ss_cmp; i++) { > - /* always clear status bit on restart if using single-shot */ > - if (config->ss_ctrl[i] || config->ss_pe_cmp[i]) > - config->ss_status[i] &= ~TRCSSCSRn_STATUS; > etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i)); > - etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i)); > + /* always clear status and pending bits on restart if using single-shot */ > + etm4x_relaxed_write32(csa, 0x0, TRCSSCSRn(i)); After confirmed with hardware team, we should preserve status bits (including STATUS and PENDING bits) during a session. So here we should set drvdata->ss_status to TRCSSCSRn. > @@ -1503,8 +1501,9 @@ static void etm4_init_arch_data(void *info) > */ > caps->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4); > for (i = 0; i < caps->nr_ss_cmp; i++) { > - drvdata->config.ss_status[i] = > - etm4x_relaxed_read32(csa, TRCSSCSRn(i)); > + drvdata->ss_status[i] = etm4x_relaxed_read32(csa, TRCSSCSRn(i)); > + drvdata->ss_status[i] &= (TRCSSCSRn_PC | TRCSSCSRn_DV | > + TRCSSCSRn_DA | TRCSSCSRn_INST); It is fine for read these capacity bits when probe, but we need to clear status when a session is starting to avoid the stale value left from previous session: drvdata->ss_status[idx] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING); We can do this in etm4_parse_event_config() for perf mode, and might create a new function (say etm4_parse_sysfs_config()) for preparing config for sysfs mode? The rest looks good to me. Thanks, Leo

1 week, 4 days

[PATCH] coresight: etm4x: Correct TRCVMIDCCTLR1 save and restore

by Leo Yan

It is a typo to use trcvmidcctlr0 to save and restore TRCVMIDCCTLR1. Use trcvmidcctlr1 instead. Fixes: f5bd523690d2 ("coresight: etm4x: Convert all register accesses") Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d565a73f0042e3e0b21fcf9cb94009cc25834d3d..c370b6bf45ef26aff29ee71630f86eae2487069a 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1979,7 +1979,7 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR0); if (drvdata->numvmidc > 4) - state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR1); + state->trcvmidcctlr1 = etm4x_read32(csa, TRCVMIDCCTLR1); state->trcclaimset = etm4x_read32(csa, TRCCLAIMCLR); @@ -2102,7 +2102,7 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata) etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR0); if (drvdata->numvmidc > 4) - etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR1); + etm4x_relaxed_write32(csa, state->trcvmidcctlr1, TRCVMIDCCTLR1); etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET); --- base-commit: 971f3474f8898ae8bbab19a9b547819a5e6fbcf1 change-id: 20260408-arm_cs_fix_trcvmidcctlr1_typo-3382c27d1c28 Best regards, -- Leo Yan <leo.yan(a)arm.com>

1 week, 4 days

[PATCH v3] coresight: ete: Always save state on power down

by James Clark

System register ETMs and ETE are unlikely to be preserved on CPU power down. The ETE DT binding also never documented "arm,coresight-loses-context-with-cpu" so nobody would have legitimately been able to use that binding to fix it and ACPI has no such binding at all. Fix it by hard coding the setting for sysreg ETMs (ETE is always sysreg) or ACPI boots. Use a local variable when setting up save_state so that it's immune to concurrent probing when devices have different configurations which is an issue with modifying the global. This fixes the following error when using Coresight with ACPI on the FVP which supports CPU PM: coresight ete0: External agent took claim tag WARNING: drivers/hwtracing/coresight/coresight-core.c:248 at coresight_disclaim_device_unlocked+0xe0/0xe8, CPU#0: perf/117 Fixes: 35e1c9163e02 ("coresight: ete: Add support for ETE tracing") Signed-off-by: James Clark <james.clark(a)linaro.org> --- Fix PM save on ETE, which is an issue that showed up on the FVP when booted with ACPI and the newly enabled idle states. --- Changes in v3: - Setup using a local variable and then check drvdata->save_state at runtime so it's immune to concurrent probing with different configs. - Link to v2: https://lore.kernel.org/r/20260505-james-cs-ete-pm_save_enable-v2-1-d39c1f1… Changes in v2: - Expand rule to also save for ACPI and sysreg ETMs. Now module param is only read for MMIO ETMs and DT. - Drop change to save the result in drvdata as the single global is simpler. - Link to v1: https://lore.kernel.org/r/20260428-james-cs-ete-pm_save_enable-v1-0-c7a90ca… --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 48 +++++++++++++++------- 1 file changed, 34 insertions(+), 14 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index d565a73f0042..591dfe0bc635 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -56,10 +56,14 @@ MODULE_PARM_DESC(boot_enable, "Enable tracing on boot"); #define PARAM_PM_SAVE_NEVER 1 /* never save any state */ #define PARAM_PM_SAVE_SELF_HOSTED 2 /* save self-hosted state only */ +/* + * Save option for ETM4. ETE, sysreg ETM4s and ACPI boots ignore this option and + * will always save. + */ static int pm_save_enable = PARAM_PM_SAVE_FIRMWARE; module_param(pm_save_enable, int, 0444); MODULE_PARM_DESC(pm_save_enable, - "Save/restore state on power down: 1 = never, 2 = self-hosted"); + "Save/restore state on power down: 1 = never, 2 = self-hosted. MMIO and DT only."); static struct etmv4_drvdata *etmdrvdata[NR_CPUS]; static void etm4_set_default_config(struct etmv4_config *config); @@ -2012,7 +2016,7 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata) { int ret = 0; - if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED) + if (!drvdata->save_state) return 0; /* @@ -2127,7 +2131,7 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata) static void etm4_cpu_restore(struct etmv4_drvdata *drvdata) { - if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED) + if (!drvdata->save_state) return; if (coresight_get_mode(drvdata->csdev)) @@ -2212,6 +2216,17 @@ static void etm4_pm_clear(void) } } +static bool etm4x_always_pm_save(struct device *dev, struct csdev_access *csa) +{ + /* + * Only IO mem ETM devices will benefit from skipping PM save and only + * DT has the option to control it, not ACPI. Otherwise system register + * based ETMs and ETEs will always lose context on CPU power down, so + * always save. + */ + return !csa->io_mem || is_acpi_device_node(dev_fwnode(dev)); +} + static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg) { int ret; @@ -2221,6 +2236,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg) struct coresight_desc desc = { 0 }; u8 major, minor; char *type_name; + bool pm_save; if (!drvdata) return -EINVAL; @@ -2248,6 +2264,21 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg) etm4_set_default(&drvdata->config); + if (etm4x_always_pm_save(dev, init_arg->csa)) + pm_save = true; + else if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE) + pm_save = coresight_loses_context_with_cpu(dev); + else + pm_save = pm_save_enable != PARAM_PM_SAVE_NEVER; + + if (pm_save) { + drvdata->save_state = devm_kmalloc(dev, + sizeof(struct etmv4_save_state), + GFP_KERNEL); + if (!drvdata->save_state) + return -ENOMEM; + } + pdata = coresight_get_platform_data(dev); if (IS_ERR(pdata)) return PTR_ERR(pdata); @@ -2305,17 +2336,6 @@ static int etm4_probe(struct device *dev) if (ret) return ret; - if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE) - pm_save_enable = coresight_loses_context_with_cpu(dev) ? - PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER; - - if (pm_save_enable != PARAM_PM_SAVE_NEVER) { - drvdata->save_state = devm_kmalloc(dev, - sizeof(struct etmv4_save_state), GFP_KERNEL); - if (!drvdata->save_state) - return -ENOMEM; - } - raw_spin_lock_init(&drvdata->spinlock); drvdata->cpu = coresight_get_cpu(dev); --- base-commit: 971f3474f8898ae8bbab19a9b547819a5e6fbcf1 change-id: 20260420-james-cs-ete-pm_save_enable-4e994e35cdac Best regards, -- James Clark <james.clark(a)linaro.org>

1 week, 4 days

[PATCH] coresight: tmc: Fix overflow when calculating is bigger than 2GiB

by Leo Yan

When specifying a 2GB AUX buffer, the ETR driver ends up allocating only a 1MB buffer instead: # echo 'file coresight-tmc-etr.c +p' > \ /sys/kernel/debug/dynamic_debug/control # perf record -e cs_etm/@tmc_etr0,timestamp=0/u -C 0 -m ,2G -- test coresight tmc_etr0: allocated buffer of size 1024KB in mode 0 The page index is an 'int' type, and shifting it by PAGE_SHIFT overflows when the resulting value exceeds 2GB. This produces a negative value, causing the driver to fall back to the minimum buffer size (1MB). Cast the page index to a wider type to accommodate large buffer sizes. Also fix a similar issue in the buffer offset calculation. Reported-by: Michiel van Tol <michiel.vantol(a)arm.com> Fixes: 99443ea19e8b ("coresight: Add generic TMC sg table framework") Fixes: eebe8dbd8630 ("coresight: tmc: Decouple the perf buffer allocation from sysfs mode") Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index cee82e52c4ea96b035f1db71b2d9a006bfc1c51e..990bbb721e1d712d7b93f1e36087fdaf9d3baa3b 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -154,7 +154,7 @@ tmc_pages_get_offset(struct tmc_pages *tmc_pages, dma_addr_t addr) for (i = 0; i < tmc_pages->nr_pages; i++) { page_start = tmc_pages->daddrs[i]; if (addr >= page_start && addr < (page_start + PAGE_SIZE)) - return i * PAGE_SIZE + (addr - page_start); + return (long)i * PAGE_SIZE + (addr - page_start); } return -EINVAL; @@ -1381,7 +1381,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event, node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); /* Use the minimum limit if the required size is smaller */ - size = nr_pages << PAGE_SHIFT; + size = (ssize_t)nr_pages << PAGE_SHIFT; size = max_t(ssize_t, size, TMC_ETR_PERF_MIN_BUF_SIZE); /* --- base-commit: eebe8dbd8630f51cf70b1f68a440cd3d7f7a914d change-id: 20260217-arm_coresight_fix_big_buffer_size-a8a41298369d Best regards, -- Leo Yan <leo.yan(a)arm.com>

1 week, 4 days

[PATCH v11 00/27] CoreSight: Refactor power management for CoreSight path

by Leo Yan

This series focuses on CoreSight path power management. The changes can be divided into four parts for review: Patches 01 - 09: Preparison for CPU PM: Fix helper enable failure handling. Refactor CPU ID stored in csdev. Move CPU lock to sysfs layer. Move per-CPU source pointer from etm-perf to core layer. Refactor etm-perf to retrieve source via per-CPU's event data for lockless and get source reference during AUX setup. Patches 10 - 12: Refactor CPU idle flow managed in the CoreSight core layer. Patches 13 - 22: Refactor path enable / disable with range, control path during CPU idle. Patches 23 - 24: Support the sink (TRBE) control during CPU idle. Patches 25 - 27: Move CPU hotplug into the core layer, and fix sysfs mode for hotplug. This series is rebased on the coresight-next branch and has been verified on Juno-r2 (ETM + ETR) and FVP RevC (ETE + TRBE). Built successfully for armv7 (ARCH=arm). --- Changes in v11: - Moved per-CPU source pointer from etm-perf to core (Suzuki). - Added grabbing/ungrabbing csdev for device reference (Suzuki). - Minor refine for error handling and logs in CPU PM (James). - Refactored etm-perf with fetching path/source from event data (Suzuki). - Fixed Helper error handling (sashiko). - Added Jie's test tag (thanks!). - Minor improvement for comments and commit logs. - Link to v10: https://lore.kernel.org/r/20260405-arm_coresight_path_power_management_impr… Changes in v10: - Removed redundant checks in ETMv4 PM callbacks (sashiko). - Added a new const structure etm4_cs_pm_ops (sashiko). - Used fine-grained spinlock on sysfs_active_config (sashiko). - Blocked notification after failures in save / restore to avoid lockups. - Changed Change CPUHP_AP_ARM_CORESIGHT_STARTING to CPUHP_AP_ARM_CORESIGHT_ONLINE so that the CPU hotplug callback runs in the thread context (sashiko). - Link to v9: https://lore.kernel.org/r/20260401-arm_coresight_path_power_management_impr… Changes in v9: - Changed to use per-CPU path pointer with lockless access. - Removed the change for adding csdev->path, the related refactoring will be sent separately. - Re-orged patches to avoid intermediate breakage (sashiko). - Link to v8: https://lore.kernel.org/r/20260325-arm_coresight_path_power_management_impr… Changes in v8: - Moved the "cpu" field in coresight_device for better pack with new patch 01 (Suzuki). - Added check if not set CPU for per_cpu_source/per_cpu_sink (Suzuki). - Renamed spinlock name in syscfg (Suzuki). - Refactored paired enable and disable path with new patches 10 and 12 (Suzuki). - Link to v7: https://lore.kernel.org/r/20260320-arm_coresight_path_power_management_impr… Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- Leo Yan (26): coresight: Handle helper enable failure properly coresight: Extract device init into coresight_init_device() coresight: Populate CPU ID into coresight_device coresight: Remove .cpu_id() callback from source ops coresight: Take hotplug lock in enable_source_store() for Sysfs mode coresight: perf: Retrieve path and source from event data coresight: Take a reference on csdev coresight: Move per-CPU source pointer to core layer coresight: Grab per-CPU source device during AUX setup coresight: Register CPU PM notifier in core layer coresight: etm4x: Hook CPU PM callbacks coresight: etm4x: Remove redundant checks in PM save and restore coresight: syscfg: Use IRQ-safe spinlock to protect active variables coresight: Move source helper disabling to coresight_disable_path() coresight: Control path with range coresight: Use helpers to fetch first and last nodes coresight: Introduce coresight_enable_source() helper coresight: Save active path for system tracers coresight: etm4x: Set active path on target CPU coresight: etm3x: Set active path on target CPU coresight: sysfs: Use source's path pointer for path control coresight: Control path during CPU idle coresight: Add PM callbacks for sink device coresight: sysfs: Increment refcount only for system tracers coresight: Move CPU hotplug callbacks to core layer coresight: sysfs: Validate CPU online status for per-CPU sources Yabin Cui (1): coresight: trbe: Save and restore state across CPU low power state drivers/hwtracing/coresight/coresight-catu.c | 2 +- drivers/hwtracing/coresight/coresight-core.c | 530 ++++++++++++++++++--- drivers/hwtracing/coresight/coresight-cti-core.c | 9 +- drivers/hwtracing/coresight/coresight-etm-perf.c | 268 ++++++----- drivers/hwtracing/coresight/coresight-etm3x-core.c | 73 +-- drivers/hwtracing/coresight/coresight-etm4x-core.c | 166 ++----- drivers/hwtracing/coresight/coresight-priv.h | 6 + drivers/hwtracing/coresight/coresight-syscfg.c | 38 +- drivers/hwtracing/coresight/coresight-syscfg.h | 2 + drivers/hwtracing/coresight/coresight-sysfs.c | 133 ++---- drivers/hwtracing/coresight/coresight-trbe.c | 61 ++- include/linux/coresight.h | 15 +- include/linux/cpuhotplug.h | 2 +- 13 files changed, 833 insertions(+), 472 deletions(-) --- base-commit: 971f3474f8898ae8bbab19a9b547819a5e6fbcf1 change-id: 20251104-arm_coresight_path_power_management_improvement-dab4966f8280 Best regards, -- Leo Yan <leo.yan(a)arm.com>

2 weeks, 2 days

Re: [PATCH v11 00/27] CoreSight: Refactor power management for CoreSight path

by Leo Yan

On Wed, May 06, 2026 at 03:33:38PM +0800, Jie Gan wrote: [...] > Tested on QCOM sa8775p-ride platform with sysfs mode: Hi Jie, very appreciate for the testing! > === 1. Prerequisites === > PASS: Running as root > PASS: CoreSight bus present > PASS: Sink: tmc_etr0 > Sink is TRBE: 0 > PASS: Source: etm0 > Source CPU: 0 > Online CPUs: 8 > All CoreSight devices: > ctcu0 > cti_sys0 > etm0 > etm1 > etm2 > etm3 > etm4 > etm5 > etm6 > etm7 > funnel0 > funnel1 > funnel2 > funnel3 > funnel4 > funnel5 > funnel6 > funnel7 > replicator0 > replicator1 > replicator2 > stm0 > tmc_etf0 > tmc_etr0 > tmc_etr1 > tpdm0 > tpdm1 > tpdm10 > tpdm11 > tpdm2 > tpdm3 > tpdm4 > tpdm5 > tpdm6 > tpdm7 > tpdm8 > tpdm9 > > === 2. Sysfs mode: basic enable/disable === > PASS: Sink tmc_etr0 enabled > PASS: Source etm0 enabled > PASS: Source etm0 disabled cleanly > PASS: Sink tmc_etr0 disabled cleanly > > === 3. Sysfs mode: repeated enable/disable cycles (10x) === > PASS: 10 enable/disable cycles completed without error > > === 4. Sysfs: enable source with no active sink === > PASS: Enable without sink returned error (expected) > > === 5. Sysfs: enable/disable all online per-CPU sources === > etm0 (cpu0): enabled OK > etm1 (cpu1): enabled OK > etm2 (cpu2): enabled OK > etm3 (cpu3): enabled OK > etm4 (cpu4): enabled OK > etm5 (cpu5): enabled OK > etm6 (cpu6): enabled OK > etm7 (cpu7): enabled OK > PASS: All online per-CPU sources enabled/disabled successfully > > === 6. csdev->cpu sysfs attribute (Patch 3: CPU ID in coresight_device) === > etm0: cpu = 0 (OK) > etm1: cpu = 1 (OK) > etm2: cpu = 2 (OK) > etm3: cpu = 3 (OK) > etm4: cpu = 4 (OK) > etm5: cpu = 5 (OK) > etm6: cpu = 6 (OK) > etm7: cpu = 7 (OK) > PASS: All 8 per-CPU sources have valid 'cpu' attribute > > === 7. CPU online validation before path build (Patch 27) === > Offlining cpu1 (source: etm1) > [ 146.339051] psci: CPU1 killed (polled 0 ms) > PASS: P27: Enable on offline cpu1 rejected before path build > (enable_source=0) > [ 146.689573] Detected PIPT I-cache on CPU1 > [ 146.689635] GICv3: CPU1: found redistributor 100 region > 0:0x0000000017a80000 > [ 146.689801] CPU1: Booted secondary processor 0x0000000100 [0x410fd4b2] > cpu1 back online > > === 8. CPU hotplug: core layer disables full sysfs path on CPU offline > (Patch 26) === > Starting sysfs trace on cpu1 (source: etm1) > Offlining cpu1 while tracing active... > [ 147.498731] psci: CPU1 killed (polled 0 ms) > PASS: P26: Source auto-disabled by core coresight_dying_cpu() on CPU offline > Sink state after hotplug: 1 > PASS: No kernel errors in dmesg during hotplug > [ 148.365194] Detected PIPT I-cache on CPU1 > [ 148.365249] GICv3: CPU1: found redistributor 100 region > 0:0x0000000017a80000 > [ 148.365393] CPU1: Booted secondary processor 0x0000000100 [0x410fd4b2] > PASS: cpu1 re-onlined > > === 9. CPU hotplug: re-enable sysfs tracing after CPU re-online === > PASS: Tracing re-enabled on cpu1 after hotplug cycle > > === 10. CPU PM: path control during CPU idle (Patch 22) === > Sleeping 4s to allow CPU idle entry (source: etm0, cpu: 0)... > Idle entries on cpu0 during test: 49 > PASS: P22: Source still enabled after idle — path save/restore working > > Thanks, > Jie

2 weeks, 2 days

Re: [PATCH v6 04/13] coresight: etm4x: exclude ss_status from drvdata->config

by Leo Yan

On Wed, Apr 22, 2026 at 02:21:54PM +0100, Yeoreum Yun wrote: [...] > @@ -573,11 +573,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) > etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i)); > > for (i = 0; i < caps->nr_ss_cmp; i++) { > - /* always clear status bit on restart if using single-shot */ > - if (config->ss_ctrl[i] || config->ss_pe_cmp[i]) > - config->ss_status[i] &= ~TRCSSCSRn_STATUS; > etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i)); > - etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i)); > + /* always clear status and pending bits on restart if using single-shot */ > + etm4x_relaxed_write32(csa, 0x0, TRCSSCSRn(i)); I am not confident what is the right way to handle the pending bit. I looked a bit Arm ARM but still no clue. In particular, I suspect it may need to be handled when disabling the trace in etm4_disable_hw(). Let's make it clear with some internal check. > @@ -1829,8 +1829,8 @@ static ssize_t sshot_ctrl_store(struct device *dev, > raw_spin_lock(&drvdata->spinlock); > idx = config->ss_idx; > config->ss_ctrl[idx] = FIELD_PREP(TRCSSCCRn_SAC_ARC_RST_MASK, val); > - /* must clear bit 31 in related status register on programming */ > - config->ss_status[idx] &= ~TRCSSCSRn_STATUS; > + /* must clear bit 31 and 30 in related status register on programming */ > + drvdata->ss_status[idx] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING); Similarly, the question is: if it is in a pending state, how can we ensure the state machine works properly with the new settings? > raw_spin_unlock(&drvdata->spinlock); > return size; > } > @@ -1879,8 +1879,8 @@ static ssize_t sshot_pe_ctrl_store(struct device *dev, > raw_spin_lock(&drvdata->spinlock); > idx = config->ss_idx; > config->ss_pe_cmp[idx] = FIELD_PREP(TRCSSPCICRn_PC_MASK, val); > - /* must clear bit 31 in related status register on programming */ > - config->ss_status[idx] &= ~TRCSSCSRn_STATUS; > + /* must clear bit 31 and 30 in related status register on programming */ > + drvdata->ss_status[idx] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING); Ditto. Thanks, Leo

2 weeks, 2 days

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