CoreSight

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[PATCH 0/9] coresight: Fix assorted bugs reported by Sashiko

by James Clark

Small fixes for bugs in the CoreSight drivers that were found by Sashiko. Mostly reference and resource leaks on error paths, plus a deadlock, a missing lock, and a sysfs store that should return -EBUSY while a sysfs session is enabled. This series depends on "coresight: Prevent per-thread events from sharing a sink" v4 [1]. That series takes coresight_mutex for perf AUX setup and adds coresight_release_path_locked(), which the etm_setup_aux() and coresight_build_path() fixes here are based on. [1]: https://lore.kernel.org/r/20261016-james-cs-multiple-per-threads-v4-0-dedf9… Signed-off-by: James Clark <james.clark(a)linaro.org> --- James Clark (9): coresight: cpu-debug: Fix PM usage counter leak in debug_enable_func() coresight: etm4x: Remove perf symlink if config registration fails coresight: etm4x: Fix truncation of nr_ext_inp coresight: etm-perf: Fix sink device reference leak in etm_setup_aux() coresight: syscfg: Take csdev lock when removing owned features coresight: syscfg: Fix deadlock in cscfg_create_device() error path coresight: Fix resource leaks on coresight_build_path() errors coresight: etm3x: Don't ignore etm_parse_event_config() errors coresight: etm3x: Prohibit modifying seq_curr_state while session is enabled drivers/hwtracing/coresight/coresight-core.c | 6 ++++-- drivers/hwtracing/coresight/coresight-cpu-debug.c | 4 ++-- drivers/hwtracing/coresight/coresight-etm-perf.c | 4 ++++ drivers/hwtracing/coresight/coresight-etm3x-core.c | 6 +++++- drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 5 +++++ drivers/hwtracing/coresight/coresight-etm4x-core.c | 1 + drivers/hwtracing/coresight/coresight-etm4x.h | 2 +- drivers/hwtracing/coresight/coresight-syscfg.c | 8 +++++++- 8 files changed, 29 insertions(+), 7 deletions(-) --- base-commit: 343cfcbb3ecfdb80aa576a428cfa3b65ad783842 change-id: 20261027-james-cs-sashiko-easy-fixes-1-692d80016a89 prerequisite-message-id: <20261016-james-cs-multiple-per-threads-v4-0-dedf961aca0e(a)linaro.org> prerequisite-patch-id: 81acda380ba25acd3845eb58d5ded812175b9631 prerequisite-patch-id: 430caddc9c87948d4e9a0d1967bf3d8a50bca06b prerequisite-patch-id: 633377150141300f7578b265fcc02eba52e592a8 prerequisite-patch-id: 9a82ffe5d705ac1fdf1250ff6bf242cfcd9d8fbf prerequisite-patch-id: cf211801575d6bd0aa7fc0f6e19c3b90cea446a0 prerequisite-patch-id: d22fee48bf4aa3e01536e4683ccd797b3dbe1c91 prerequisite-patch-id: 55eeffb37cae55a1f47c2827899e0512b47a6efa prerequisite-patch-id: c542d74cd4bc76158d5872bab12b8bd7a00f0c27 prerequisite-patch-id: 71cd37ed83d3e01d7a0321cdfa5cfc5ee113fe7b prerequisite-patch-id: 74c1e3ed6dba4e25bfd3c39f06d43b079eed45e1 Best regards, -- James Clark <james.clark(a)linaro.org>

6 days, 5 hours

Re: [PATCH v2] perf: arm_spe: Support heterogeneous ACPI systems

by Jeremy Linton

Hi, This largely looks reasonable, some comments inline. On 10/20/26 9:03 PM, Johnny.Fan wrote: > From: "Johnny.Fan" <Johnny.Fan(a)cixtech.com> > > On heterogeneous ACPI systems, not all CPUs implement SPE, and the > ones that do may use different PPIs. The MADT describes this per > GICC entry: a CPU without SPE reports a zero SPE overflow interrupt, > and the PPTT hetero id identifies CPUs of the same implementation. > > The current code registers a single platform device and gives up if > the GICC entries disagree on either the hetero id or the interrupt, > so SPE is unavailable on such systems even though the firmware > describes it. > > Group the CPUs by (hetero id, SPE interrupt) and register one > platform device per group. A GSI may be shared between groups with > non-overlapping CPU masks, so only unregister the GSI mapping when > no other group uses the same interrupt, as the mapping is not > reference counted. > > These synthetic devices have no fwnode, so the firmware-described > IRQ affinity cannot tell which CPUs implement the feature. Pass the > CPU mask as platform data and have the drivers prefer it over the > IRQ affinity when present. > > Apply the same treatment to TRBE, which shares this registration > code. TRBE must also pass a stable copy of the mask to > request_percpu_irq_affinity(), since supported_cpus is pruned as > CPUs are probed. > > Tested on a CIX sky1 SoC with heterogeneous SPE support. > > Signed-off-by: Johnny.Fan <Johnny.Fan(a)cixtech.com> > Reviewed-by: Fugang Duan <fugang.duan(a)cixtech.com> > --- > drivers/hwtracing/coresight/coresight-trbe.c | 22 +- > drivers/perf/arm_pmu_acpi.c | 211 ++++++++++++------- It makes sense to split the device creation portion in arm_pmu_acpi.c into its own patch separate from the consumption IMHO. > drivers/perf/arm_spe_pmu.c | 10 +- > include/linux/perf/arm_pmu.h | 10 + > 4 files changed, 176 insertions(+), 77 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c > index c7cbca45f2de..0c4bc8fbcaf3 100644 > --- a/drivers/hwtracing/coresight/coresight-trbe.c > +++ b/drivers/hwtracing/coresight/coresight-trbe.c > @@ -158,6 +158,7 @@ struct trbe_drvdata { > struct hlist_node hotplug_node; > int irq; > cpumask_t supported_cpus; > + cpumask_t irq_affinity; > enum cpuhp_state trbe_online; > struct platform_device *pdev; > }; > @@ -1533,6 +1534,8 @@ static void arm_trbe_remove_cpuhp(struct trbe_drvdata *drvdata) > static int arm_trbe_probe_irq(struct platform_device *pdev, > struct trbe_drvdata *drvdata) > { > + const struct arm_pmu_acpi_dev_data *acpi_data = > + dev_get_platdata(&pdev->dev); > const struct cpumask *affinity; > int ret; > > @@ -1547,14 +1550,27 @@ static int arm_trbe_probe_irq(struct platform_device *pdev, > return -EINVAL; > } > > - cpumask_copy(&drvdata->supported_cpus, affinity); > + /* > + * The ACPI path has no fwnode describing which CPUs implement TRBE, > + * so it passes the mask explicitly. DT devices still use the > + * firmware-described IRQ affinity. > + */ > + cpumask_copy(&drvdata->supported_cpus, > + acpi_data ? &acpi_data->cpus : affinity); > + > + /* > + * supported_cpus gets pruned as CPUs are probed, so keep a stable > + * copy for the IRQ action. > + */ > + cpumask_copy(&drvdata->irq_affinity, &drvdata->supported_cpus); > > drvdata->handle = alloc_percpu(struct perf_output_handle *); > if (!drvdata->handle) > return -ENOMEM; > > - ret = request_percpu_irq_affinity(drvdata->irq, arm_trbe_irq_handler, DRVNAME, > - affinity, drvdata->handle); > + ret = request_percpu_irq_affinity(drvdata->irq, arm_trbe_irq_handler, > + DRVNAME, &drvdata->irq_affinity, > + drvdata->handle); > if (ret) { > free_percpu(drvdata->handle); > return ret; > diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c > index ca6bf8f86cfe..fdf39673648f 100644 > --- a/drivers/perf/arm_pmu_acpi.c > +++ b/drivers/perf/arm_pmu_acpi.c > @@ -12,6 +12,8 @@ > #include <linux/irqdesc.h> > #include <linux/percpu.h> > #include <linux/perf/arm_pmu.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > > #include <asm/cpu.h> > #include <asm/cputype.h> > @@ -68,91 +70,165 @@ static void arm_pmu_acpi_unregister_irq(int cpu) > acpi_unregister_gsi(gsi); > } > > -static int __maybe_unused > -arm_acpi_register_pmu_device(struct platform_device *pdev, u8 len, > - u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *)) > +struct arm_pmu_acpi_group { > + int hetid; > + u16 gsi; > + struct cpumask cpus; > +}; > + > +static int arm_acpi_find_group(struct arm_pmu_acpi_group *groups, int nr_groups, > + int hetid, u16 gsi) > { > - int cpu, this_hetid, hetid, irq, ret; > - u16 this_gsi = 0, gsi = 0; > + int i; > > - /* > - * Ensure that platform device must have IORESOURCE_IRQ > - * resource to hold gsi interrupt. > - */ > - if (pdev->num_resources != 1) > - return -ENXIO; > + for (i = 0; i < nr_groups; i++) { > + if (groups[i].hetid == hetid && groups[i].gsi == gsi) > + return i; > + } > + > + return -1; > +} > + > +static bool arm_acpi_gsi_is_shared(struct arm_pmu_acpi_group *groups, > + int nr_groups, int idx) > +{ > + int i; > + > + for (i = 0; i < nr_groups; i++) { > + if (i != idx && groups[i].gsi == groups[idx].gsi) > + return true; > + } > + > + return false; > +} > + > +static int arm_acpi_register_group(struct arm_pmu_acpi_group *group, > + const char *name, bool gsi_shared) > +{ > + struct arm_pmu_acpi_dev_data data = { }; > + struct platform_device *pdev; > + struct resource res; > + int irq, ret; > + > + irq = acpi_register_gsi(NULL, group->gsi, ACPI_LEVEL_SENSITIVE, > + ACPI_ACTIVE_HIGH); > + if (irq < 0) > + return irq; > + > + pdev = platform_device_alloc(name, PLATFORM_DEVID_AUTO); > + if (!pdev) { > + ret = -ENOMEM; > + goto err_unreg; > + } > > - if (pdev->resource[0].flags != IORESOURCE_IRQ) > - return -ENXIO; > + res = DEFINE_RES_IRQ(irq); > + data.cpus = group->cpus; > > + ret = platform_device_add_resources(pdev, &res, 1); > + if (ret) > + goto err_put; > + > + ret = platform_device_add_data(pdev, &data, sizeof(data)); > + if (ret) > + goto err_put; > + > + ret = platform_device_add(pdev); > + if (!ret) > + return 0; > + > +err_put: > + platform_device_put(pdev); > +err_unreg: > /* > - * Sanity check all the GICC tables for the same interrupt > - * number. For now, only support homogeneous ACPI machines. > + * The GSI mapping is not reference counted, so only drop it if no > + * other group shares it. > */ > + if (!gsi_shared) > + acpi_unregister_gsi(group->gsi); This is a bit odd, if whatever fails, and gets here happens on all the paths associated with the shared GSI, then that GSI is never unregistered and the resource is leaked. > + > + return ret; > +} > + > +static int __maybe_unused > +arm_acpi_register_pmu_devices(const char *name, u8 len, > + u16 (*parse_gsi)(struct acpi_madt_generic_interrupt *)) > +{ > + struct arm_pmu_acpi_group *groups; > + int cpu, i, nr_cpus = 0, nr_groups = 0, nr_devices = 0; > + int last_err = 0, ret; > + > for_each_possible_cpu(cpu) { > struct acpi_madt_generic_interrupt *gicc; > > gicc = acpi_cpu_get_madt_gicc(cpu); > if (gicc->header.length < len) > - return gsi ? -ENXIO : 0; > - > - this_gsi = parse_gsi(gicc); > - this_hetid = find_acpi_cpu_topology_hetero_id(cpu); > - if (!gsi) { > - hetid = this_hetid; > - gsi = this_gsi; > - } else if (hetid != this_hetid || gsi != this_gsi) { > - pr_warn("ACPI: %s: must be homogeneous\n", pdev->name); > - return -ENXIO; > - } > + continue; This continue seems like a mistake, if the firmware has provided unreliable tables we should abort all device creation, even if that means some subset of the SPE devices which appear to be correct aren't created. > + if (parse_gsi(gicc)) > + nr_cpus++; > } > > - if (!this_gsi) > + if (!nr_cpus) > return 0; > > - irq = acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_HIGH); > - if (irq < 0) { > - pr_warn("ACPI: %s Unable to register interrupt: %d\n", pdev->name, gsi); > - return -ENXIO; > - } > + groups = kcalloc(nr_cpus, sizeof(*groups), GFP_KERNEL); And this seemed a bit chunky because in theory this could be NR_CPUS, which made me initially say, skip counting the cores and just allocate the max, then I realized its close to having kcalloc() failures if there are a lot of cores in the machine since this allocation becomes multiple MB. I think we are creating a future headache and need something smarter than counting the number of cores with valid SPE/TRBE interrupts. > + if (!groups) > + return -ENOMEM; > > - pdev->resource[0].start = irq; > - ret = platform_device_register(pdev); > - if (ret) > - acpi_unregister_gsi(gsi); > + for_each_possible_cpu(cpu) { > + struct acpi_madt_generic_interrupt *gicc; > + int hetid; > + u16 gsi; > > - return ret; > -} > + gicc = acpi_cpu_get_madt_gicc(cpu); > + if (gicc->header.length < len) > + continue; same continue issue here as above> > -#if IS_ENABLED(CONFIG_ARM_SPE_PMU) > -static struct resource spe_resources[] = { > - { > - /* irq */ > - .flags = IORESOURCE_IRQ, > + gsi = parse_gsi(gicc); > + if (!gsi) > + continue; > + > + hetid = find_acpi_cpu_topology_hetero_id(cpu); If groups were say a linked list (or something else dynamic) you could just use the failure case here to allocate the next entry and simply skip the first loop iteration above counting cpus. > + i = arm_acpi_find_group(groups, nr_groups, hetid, gsi); > + if (i < 0) { > + i = nr_groups++; > + groups[i].hetid = hetid; > + groups[i].gsi = gsi; > + } > + > + cpumask_set_cpu(cpu, &groups[i].cpus); > } > -}; > > -static struct platform_device spe_dev = { > - .name = ARMV8_SPE_PDEV_NAME, > - .id = -1, > - .resource = spe_resources, > - .num_resources = ARRAY_SIZE(spe_resources) > -}; > + for (i = 0; i < nr_groups; i++) { > + ret = arm_acpi_register_group(&groups[i], name, > + arm_acpi_gsi_is_shared(groups, > + nr_groups, i)); > + if (ret) { > + pr_warn("ACPI: %s: %*pbl: add device failed (%d)\n", > + name, cpumask_pr_args(&groups[i].cpus), ret); > + last_err = ret; > + } else { > + nr_devices++; > + } > + } > + > + kfree(groups); > + > + return nr_devices ? 0 : last_err; > +} > > +#if IS_ENABLED(CONFIG_ARM_SPE_PMU) > static u16 arm_spe_parse_gsi(struct acpi_madt_generic_interrupt *gicc) > { > return gicc->spe_interrupt; > } > > -/* > - * For lack of a better place, hook the normal PMU MADT walk > - * and create a SPE device if we detect a recent MADT with > - * a homogeneous PPI mapping. > - */ > static void arm_spe_acpi_register_device(void) > { > - int ret = arm_acpi_register_pmu_device(&spe_dev, ACPI_MADT_GICC_SPE, > - arm_spe_parse_gsi); > + int ret; > + > + ret = arm_acpi_register_pmu_devices(ARMV8_SPE_PDEV_NAME, > + ACPI_MADT_GICC_SPE, > + arm_spe_parse_gsi); > if (ret) > pr_warn("ACPI: SPE: Unable to register device\n"); > } > @@ -163,20 +239,6 @@ static inline void arm_spe_acpi_register_device(void) > #endif /* CONFIG_ARM_SPE_PMU */ > > #if IS_ENABLED(CONFIG_CORESIGHT_TRBE) > -static struct resource trbe_resources[] = { > - { > - /* irq */ > - .flags = IORESOURCE_IRQ, > - } > -}; > - > -static struct platform_device trbe_dev = { > - .name = ARMV8_TRBE_PDEV_NAME, > - .id = -1, > - .resource = trbe_resources, > - .num_resources = ARRAY_SIZE(trbe_resources) > -}; > - > static u16 arm_trbe_parse_gsi(struct acpi_madt_generic_interrupt *gicc) > { > return gicc->trbe_interrupt; > @@ -184,8 +246,11 @@ static u16 arm_trbe_parse_gsi(struct acpi_madt_generic_interrupt *gicc) > > static void arm_trbe_acpi_register_device(void) > { > - int ret = arm_acpi_register_pmu_device(&trbe_dev, ACPI_MADT_GICC_TRBE, > - arm_trbe_parse_gsi); > + int ret; > + > + ret = arm_acpi_register_pmu_devices(ARMV8_TRBE_PDEV_NAME, > + ACPI_MADT_GICC_TRBE, > + arm_trbe_parse_gsi); > if (ret) > pr_warn("ACPI: TRBE: Unable to register device\n"); > } > diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c > index b70f3fedf028..712b7f187301 100644 > --- a/drivers/perf/arm_spe_pmu.c > +++ b/drivers/perf/arm_spe_pmu.c > @@ -1330,6 +1330,8 @@ static void arm_spe_pmu_dev_teardown(struct arm_spe_pmu *spe_pmu) > static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu) > { > struct platform_device *pdev = spe_pmu->pdev; > + const struct arm_pmu_acpi_dev_data *acpi_data = > + dev_get_platdata(&pdev->dev); > const struct cpumask *affinity; > int irq; > > @@ -1342,7 +1344,13 @@ static int arm_spe_pmu_irq_probe(struct arm_spe_pmu *spe_pmu) > return -EINVAL; > } > > - cpumask_copy(&spe_pmu->supported_cpus, affinity); > + /* > + * The ACPI path has no fwnode describing which CPUs implement SPE, > + * so it passes the mask explicitly. DT devices still use the > + * firmware-described IRQ affinity. > + */ > + cpumask_copy(&spe_pmu->supported_cpus, > + acpi_data ? &acpi_data->cpus : affinity); > > spe_pmu->irq = irq; > return 0; > diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h > index 02d2c7f45b52..7f1c03c55025 100644 > --- a/include/linux/perf/arm_pmu.h > +++ b/include/linux/perf/arm_pmu.h > @@ -8,6 +8,7 @@ > #ifndef __ARM_PMU_H__ > #define __ARM_PMU_H__ > > +#include <linux/cpumask.h> > #include <linux/interrupt.h> > #include <linux/perf_event.h> > #include <linux/platform_device.h> > @@ -199,6 +200,15 @@ void armpmu_free_irq(struct arm_pmu * __percpu *armpmu, int irq, int cpu); > #define ARMV8_SPE_PDEV_NAME "arm,spe-v1" > #define ARMV8_TRBE_PDEV_NAME "arm,trbe" > > +/* > + * Per-device CPU mask passed by the ACPI MADT walk. The synthetic > + * platform devices have no fwnode, so the IRQ affinity cannot describe > + * which CPUs actually implement the feature. > + */ > +struct arm_pmu_acpi_dev_data { > + struct cpumask cpus; > +}; > + > /* Why does everything I do descend into this? */ > #define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \ > (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi Thanks for working on this. Jeremy

6 days, 16 hours

Re: [PATCH v2 2/4] coresight: syscfg: Match feature capabilities separately from device class

by Leo Yan

On Mon, Oct 12, 2026 at 04:05:21PM -0700, Amir Ayupov wrote: [...] > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -30,6 +30,12 @@ > #define CS_CFG_MATCH_CLASS_SRC_ALL 0x0001 /* match any source */ > #define CS_CFG_MATCH_CLASS_SRC_ETM4 0x0002 /* match any ETMv4 device */ It is good to introduce a marco: #define CS_CFG_MATCH_CLASS_MASK GENMASK_U32(7, 0) > +/* > + * flags defining device capabilities a feature can require. A feature loads on > + * a device that matches one of its classes and has all of its capabilities. > + */ > +#define CS_CFG_MATCH_CAP_MASK 0x0000ff00 To make the mask explicitly 32-bit unsigned: #define CS_CFG_MATCH_CAP_MASK GENMASK_U32(15, 8) > + > /* flags defining device instance matching - used in config match desc data. */ > #define CS_CFG_MATCH_INST_ANY 0x80000000 /* any instance of a class */ Not an issue with this patch, but CS_CFG_MATCH_INST_ANY appears to be unused and could be removed in a separate cleanup patch. > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c > index a816c22c87bc8..1545d64afec01 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c > @@ -172,7 +172,21 @@ cscfg_alloc_csdev_feat(struct coresight_device *csdev, struct cscfg_feature_desc > } > > /* load one feature into one coresight device */ > +/* > + * A feature matches a device that shares one of its class flags and has all of > + * the capability flags it requires. > + */ > +static bool cscfg_match_feat_csdev(u32 feat_flags, u32 csdev_flags) > +{ > + u32 caps = feat_flags & CS_CFG_MATCH_CAP_MASK; > + > + return (feat_flags & csdev_flags & ~CS_CFG_MATCH_CAP_MASK) && > + (csdev_flags & caps) == caps; For clearer comparison conditions: /* Class type must be matches */ if ((feat_flags & CS_CFG_MATCH_CLASS_MASK) != (csdev_flags & CS_CFG_MATCH_CLASS_MASK) return false; /* No required capabilities miss from the device */ if (feat_flags & ~csdev_flags & CS_CFG_MATCH_CAP_MASK) return false; return true; Thanks, Leo

1 week

Re: [PATCH] [v1] coresight: funnel: inport schedule by priority can not take work

by Leo Yan

Hi, On Sun, Oct 25, 2026 at 09:13:07PM +0800, Chao Xu wrote: > Before enable funnel, priority must be set. Changing the port > priorities in real time is not supported. > If the priority control register is written when one or more of ports > are enable, then the write is silently rejected. Could you cite the relevant documentation in commit log? The CoreSight SoC-600 TRM, section 9.11.2, PRIORITYCONTROL, a funnel rejects priority register writes whenever any port is enabled. The current sequence therefore prevent the configured priorities from taking effect. Write the priority register before enabling the first port. > Signed-off-by: Chao Xu <xuchao066(a)163.com> > --- > drivers/hwtracing/coresight/coresight-funnel.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c > index af40814ce560..17f985798d7f 100644 > --- a/drivers/hwtracing/coresight/coresight-funnel.c > +++ b/drivers/hwtracing/coresight/coresight-funnel.c > @@ -66,8 +66,8 @@ static int dynamic_funnel_enable_hw(struct funnel_drvdata *drvdata, int port) > functl &= ~FUNNEL_HOLDTIME_MASK; > functl |= FUNNEL_HOLDTIME; > functl |= (1 << port); > - writel_relaxed(functl, drvdata->base + FUNNEL_FUNCTL); > writel_relaxed(drvdata->priority, drvdata->base + FUNNEL_PRICTL); > + writel_relaxed(functl, drvdata->base + FUNNEL_FUNCTL); Please move the priority write into the first port branch: /* Claim the device only when we enable the first slave */ if (!(functl & FUNNEL_ENSx_MASK)) { rc = coresight_claim_device_unlocked(csdev); if (rc) goto done; /* Update priorities while all ports are disabled */ writel_relaxed(drvdata->priority, drvdata->base + FUNNEL_PRICTL); } Thanks, Leo

1 week

[PATCH] Revert "perf/aux: Allocate non-contiguous AUX pages by default"

by Leo Yan

This reverts commit 18049c8cff9cc89daadc4df6975f7d9069638926. The original commit claimed that contiguous AUX pages unnecessarily exacerbate fragmentation for SPE, TRBE and ETR. This is not generally valid: larger allocations can keep pages with the same lifetime together, while order-0 allocations can scatter them across large blocks and prevent free pages from coalescing [1]. The follow-up discussion [2] has not established how forcing order-0 allocations addresses the reported problem. TRBE and SPE write to virtually addressed buffers. The TRBE L1 TLB has one entry on Neoverse V2 [3] and two on Neoverse V3 [4]. Small mappings increase translation pressure, and TTW stalls can contribute to FIFO overflow and trace loss on TRBE. Larger allocations provide contiguous, aligned chunks for PMD or contiguous-PTE mappings with the proposed vmap() support [5]. With the proposed vmap() support already applied, the tests in [2] showed that preferring larger AUX allocations reduced L2 data TLB refills by 99.68% in the TRBE test and 34.74% in the SPE test. Restore the previous policy of trying higher-order allocations first. The allocator already uses __GFP_NORETRY and falls back to smaller orders, including order 0, when larger allocations fail. Remove PERF_PMU_CAP_AUX_PREFER_LARGE, since the restored default provides that preference. Intel PT retains its existing allocation behaviour, with no functional change. [1] https://lore.kernel.org/all/aPjrRkjiIt6HmXmT@casper.infradead.org/ [2] https://lore.kernel.org/linux-arm-kernel/20260810-perf_aux_trace_large_gran… [3] https://documentation-service.arm.com/static/633fe1ec4c59b30b517730b8#page=… [4] https://documentation-service.arm.com/static/67361bd2c7fc0d1f211da382#page=… [5] https://lore.kernel.org/linux-mm/20260715120813.3609949-1-jiangwen6@xiaomi.… Signed-off-by: Leo Yan <leo.yan(a)arm.com> --- arch/x86/events/intel/pt.c | 2 -- include/linux/perf_event.h | 5 ++--- kernel/events/ring_buffer.c | 29 +++++++++-------------------- 3 files changed, 11 insertions(+), 25 deletions(-) diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 49349afee6119fb6fad815c847cb3cd9daa97604..3782af40f0832a874a7f0b60961d6652513de241 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -1896,8 +1896,6 @@ static __init int pt_init(void) if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries)) pt_pmu.pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG; - else - pt_pmu.pmu.capabilities = PERF_PMU_CAP_AUX_PREFER_LARGE; pt_pmu.pmu.capabilities |= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE | diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index eb3f7bab498ca9bee9ce7193744943b24ab2e0c5..b8d8b005f5c8a7c1def7cad02230bf9ffb876bd6 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -304,9 +304,8 @@ struct perf_event_pmu_context; #define PERF_PMU_CAP_AUX_OUTPUT 0x0080 #define PERF_PMU_CAP_EXTENDED_HW_TYPE 0x0100 #define PERF_PMU_CAP_AUX_PAUSE 0x0200 -#define PERF_PMU_CAP_AUX_PREFER_LARGE 0x0400 -#define PERF_PMU_CAP_MEDIATED_VPMU 0x0800 -#define PERF_PMU_CAP_SIMD_REGS 0x1000 +#define PERF_PMU_CAP_MEDIATED_VPMU 0x0400 +#define PERF_PMU_CAP_SIMD_REGS 0x0800 /** * pmu::scope diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 64d4dbdc6c071b72b670dd044616f52981206ae8..95f4fbdfd2764de5b72d901d778c46302f525fad 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -684,15 +684,7 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event, { bool overwrite = !(flags & RING_BUFFER_WRITABLE); int node = (event->cpu == -1) ? -1 : cpu_to_node(event->cpu); - bool use_contiguous_pages = event->pmu->capabilities & ( - PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_AUX_PREFER_LARGE); - /* - * Initialize max_order to 0 for page allocation. This allocates single - * pages to minimize memory fragmentation. This is overridden if the - * PMU needs or prefers contiguous pages (use_contiguous_pages = true). - */ - int max_order = 0; - int ret = -ENOMEM; + int ret = -ENOMEM, max_order; if (!has_aux(event)) return -EOPNOTSUPP; @@ -702,8 +694,8 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event, if (!overwrite) { /* - * Watermark defaults to half the buffer, to aid PMU drivers - * in double buffering. + * Watermark defaults to half the buffer, and so does the + * max_order, to aid PMU drivers in double buffering. */ if (!watermark) watermark = min_t(unsigned long, @@ -711,19 +703,16 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event, (unsigned long)nr_pages << (PAGE_SHIFT - 1)); /* - * If using contiguous pages, use aux_watermark as the basis - * for chunking to help PMU drivers honor the watermark. + * Use aux_watermark as the basis for chunking to + * help PMU drivers honor the watermark. */ - if (use_contiguous_pages) - max_order = get_order(watermark); + max_order = get_order(watermark); } else { /* - * If using contiguous pages, we need to start with the - * max_order that fits in nr_pages, not the other way around, - * hence ilog2() and not get_order. + * We need to start with the max_order that fits in nr_pages, + * not the other way around, hence ilog2() and not get_order. */ - if (use_contiguous_pages) - max_order = ilog2(nr_pages); + max_order = ilog2(nr_pages); watermark = 0; } --- base-commit: 21a7f44fd0765fcc5194130b28767786eba1d1e7 change-id: 20261025-perf_revert_prefer_large_alloc-a0177d6379f6 Best regards, -- Leo Yan <leo.yan(a)arm.com>

1 week, 1 day

Re: [PATCH v4 7/7] coresight: Add pmu_pulse/extout_pulse

by James Clark

On 26/10/2026 05:48, Amir Ayupov wrote: > Add ETMv4 configuration 'pmu_pulse' with 'extout_pulse' feature which > requires an ETE whose PMU counts its external outputs > (CS_CFG_MATCH_CAP_TRCEXTOUT): event 1 selects the always-true > resource and drives TRCEXTOUT1 PMU event which pulses on every cycle > while the trace unit is enabled. > > Assisted-by: Devmate:Opus-5.5 > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > Reviewed-by: Daniel Pereira <danielmaraboo(a)gmail.com> > --- > .../trace/coresight/coresight-config.rst | 5 ++ > .../trace/coresight/coresight-perf.rst | 15 +++++ > drivers/hwtracing/coresight/Makefile | 1 + > .../coresight/coresight-cfg-pmu-pulse.c | 55 +++++++++++++++++++ > .../coresight/coresight-cfg-preload.c | 2 + > .../coresight/coresight-cfg-preload.h | 2 + > 6 files changed, 80 insertions(+) > create mode 100644 drivers/hwtracing/coresight/coresight-cfg-pmu-pulse.c > > diff --git a/Documentation/trace/coresight/coresight-config.rst b/Documentation/trace/coresight/coresight-config.rst > index 6d5ffa6f73471..3eed728bf0de1 100644 > --- a/Documentation/trace/coresight/coresight-config.rst > +++ b/Documentation/trace/coresight/coresight-config.rst > @@ -129,6 +129,11 @@ The following steps take place in the operation of a configuration. > > 5) At the end of the perf session, the configuration will be disabled. > > +The built-in 'pmu_pulse' configuration pulses ETM external output 1 for a PMU > +event to count. It only pulses while the ETM is enabled, so combined with AUX > +pause and resume the PMU event can time each trace window (see > +coresight-perf.rst). > + > > Viewing Configurations and Features > =================================== > diff --git a/Documentation/trace/coresight/coresight-perf.rst b/Documentation/trace/coresight/coresight-perf.rst > index 0a77741a431ef..6770a455c6b59 100644 > --- a/Documentation/trace/coresight/coresight-perf.rst > +++ b/Documentation/trace/coresight/coresight-perf.rst > @@ -109,6 +109,21 @@ Example for triggering AUX pause and resume with PMU event:: > -e cycles/aux-action=pause,period=10000000/ \ > -e cycles/aux-action=resume,period=1050000/ -- sleep 1 > > +ETM-timed pause events > +~~~~~~~~~~~~~~~~~~~~~~ > + > +The built-in ``pmu_pulse`` configuration pulses ETM external output 1 on every > +cycle of allowed trace, and a PMU event counting that output pauses trace after > +``N`` pulses, here 1000 cycles:: > + > + perf record -a -e cs_etm/pmu_pulse,aux-action=start-paused/u \ > + -e cycles/aux-action=resume,period=10000000/u \ > + -e trcextout1/aux-action=pause,period=1000/u \ > + -- sleep 1 > + > +Each window is about ``N`` traced cycles plus the pause interrupt latency. > +The configuration only loads on an ETE whose PMU counts its external outputs. > + > Perf test - Verify kernel and userspace perf CoreSight work > ----------------------------------------------------------- > > diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile > index ab16d06783a57..568e797ac5a17 100644 > --- a/drivers/hwtracing/coresight/Makefile > +++ b/drivers/hwtracing/coresight/Makefile > @@ -28,6 +28,7 @@ obj-$(CONFIG_CORESIGHT) += coresight.o > coresight-y := coresight-core.o coresight-etm-perf.o coresight-platform.o \ > coresight-sysfs.o coresight-syscfg.o coresight-config.o \ > coresight-cfg-preload.o coresight-cfg-afdo.o coresight-cfg-pstop.o \ > + coresight-cfg-pmu-pulse.o \ > coresight-syscfg-configfs.o coresight-trace-id.o > obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o > coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \ > diff --git a/drivers/hwtracing/coresight/coresight-cfg-pmu-pulse.c b/drivers/hwtracing/coresight/coresight-cfg-pmu-pulse.c > new file mode 100644 > index 0000000000000..61472154dd02a > --- /dev/null > +++ b/drivers/hwtracing/coresight/coresight-cfg-pmu-pulse.c > @@ -0,0 +1,55 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Pulse ETM external output 1 on every traced cycle for a PMU event to count. > + * Based on coresight-cfg-afdo.c > + */ > + > +#include "coresight-config.h" > + > +/* ETMv4 includes and features */ > +#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X) > +#include "coresight-etm4x-cfg.h" > + > +/* > + * extout_pulse feature: event 1 selects the always-true resource, so ETM > + * external output 1 pulses on every cycle while the trace unit is enabled. A > + * PMU event counting that output (TRCEXTOUT1), for example with > + * aux-action=pause, then fires after as many traced cycles as its sample > + * period. Event 0 is avoided because it is the trace unit trigger, and the > + * TRBE driver treats a detected trigger as fatal. > + */ > +static struct cscfg_regval_desc extout_pulse_regs[] = { > + /* event 1: resource selector 1 (always true), drives external output 1 */ > + { > + .type = CS_CFG_REG_TYPE_STD | CS_CFG_REG_TYPE_VAL_MASK, > + .offset = TRCEVENTCTL0R, > + .val32 = 0x0100, > + .mask32 = 0xff00, > + }, > + /* end of regs */ > +}; > + > +struct cscfg_feature_desc extout_pulse_etm4x = { > + .name = "extout_pulse", > + .description = "Pulse external output 1 on every traced cycle.\n", > + .match_flags = CS_CFG_MATCH_CLASS_SRC_ETM4 | CS_CFG_MATCH_CAP_TRCEXTOUT, > + .nr_regs = ARRAY_SIZE(extout_pulse_regs), > + .regs_desc = extout_pulse_regs, > +}; > + > +/* create a pmu_pulse configuration */ > + > +static const char *pmu_pulse_ref_names[] = { > + "extout_pulse", > +}; > + > +struct cscfg_config_desc pmu_pulse_etm4x = { > + .name = "pmu_pulse", > + .description = "Pulse ETM external output 1 on every traced cycle for the PMU\n" > + "to count as TRCEXTOUT1\n", > + .nr_feat_refs = ARRAY_SIZE(pmu_pulse_ref_names), > + .feat_ref_names = pmu_pulse_ref_names, > +}; > + > +/* end of ETM4x configurations */ > +#endif /* IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X) */ > diff --git a/drivers/hwtracing/coresight/coresight-cfg-preload.c b/drivers/hwtracing/coresight/coresight-cfg-preload.c > index 4980e68483c5b..a9a60a1c40845 100644 > --- a/drivers/hwtracing/coresight/coresight-cfg-preload.c > +++ b/drivers/hwtracing/coresight/coresight-cfg-preload.c > @@ -14,6 +14,7 @@ static struct cscfg_feature_desc *preload_feats[] = { > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X) > &strobe_etm4x, > &gen_etrig_etm4x, > + &extout_pulse_etm4x, > #endif > NULL > }; > @@ -22,6 +23,7 @@ static struct cscfg_config_desc *preload_cfgs[] = { > #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X) > &afdo_etm4x, > &pstop_etm4x, > + &pmu_pulse_etm4x, > #endif > NULL > }; > diff --git a/drivers/hwtracing/coresight/coresight-cfg-preload.h b/drivers/hwtracing/coresight/coresight-cfg-preload.h > index 291ba530a6a52..0058627f65ae5 100644 > --- a/drivers/hwtracing/coresight/coresight-cfg-preload.h > +++ b/drivers/hwtracing/coresight/coresight-cfg-preload.h > @@ -12,4 +12,6 @@ extern struct cscfg_feature_desc strobe_etm4x; > extern struct cscfg_config_desc afdo_etm4x; > extern struct cscfg_feature_desc gen_etrig_etm4x; > extern struct cscfg_config_desc pstop_etm4x; > +extern struct cscfg_feature_desc extout_pulse_etm4x; > +extern struct cscfg_config_desc pmu_pulse_etm4x; > #endif Reviewed-by: James Clark <james.clark(a)linaro.org>

1 week, 1 day

Re: [PATCH v4 6/7] coresight: etm4x: Report whether the PMU counts the external outputs

by James Clark

On 26/10/2026 05:48, Amir Ayupov wrote: > Some CPUs count the trace unit's external outputs as the PMU common > events TRCEXTOUT0-3 (0x4010-0x4013), which lets a configuration drive a > PMU event from trace unit events. Other CPUs, Neoverse N1 for example, > have no such events, and a feature relying on them would silently do > nothing there. > > Detect at probe, on the trace unit's CPU, whether the PMU counts every > external output: the trace unit has an external output for each of its > events (caps.nr_event), and pmuv3_event_implemented() reports whether > the PMU implements TRCEXTOUTn. Only check ETE: per its specification, an > implemented TRCEXTOUTn event counts external output n, while whether that > output is also an external input is IMPLEMENTATION DEFINED. > > Add a CS_CFG_MATCH_CAP_TRCEXTOUT capability match flag, set it on those > trace units, and show it in the feature's configfs 'matches' attribute. > With capabilities matched separately from the device class, a feature > that requires it only loads on those trace units. > > Assisted-by: Devmate:Opus-5.5 > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > .../hwtracing/coresight/coresight-config.h | 2 ++ > .../hwtracing/coresight/coresight-etm4x-cfg.c | 6 ++++- > .../coresight/coresight-etm4x-core.c | 26 +++++++++++++++++++ > drivers/hwtracing/coresight/coresight-etm4x.h | 3 +++ > .../coresight/coresight-syscfg-configfs.c | 3 +++ > 5 files changed, 39 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h > index 220bc54f8e5e1..4cf53230854d0 100644 > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -38,6 +38,8 @@ > * a device that matches one of its classes and has all of its capabilities. > */ > #define CS_CFG_MATCH_CAP_MASK GENMASK_U32(15, 8) > +/* the PMU counts the trace unit's external outputs as TRCEXTOUTn */ > +#define CS_CFG_MATCH_CAP_TRCEXTOUT BIT(8) > > /* > * Limit number of presets in a configuration > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > index 52cb036bb04b9..9e4dc5950c13d 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > @@ -176,9 +176,13 @@ static int etm4_cfg_load_feature(struct coresight_device *csdev, > > int etm4_cscfg_register(struct coresight_device *csdev) > { > + struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > struct cscfg_csdev_feat_ops ops; > + u32 match_flags = CS_CFG_ETM4_MATCH_FLAGS; > > ops.load_feat = &etm4_cfg_load_feature; > + if (drvdata->caps.trcextout) > + match_flags |= CS_CFG_MATCH_CAP_TRCEXTOUT; > > - return cscfg_register_csdev(csdev, CS_CFG_ETM4_MATCH_FLAGS, &ops); > + return cscfg_register_csdev(csdev, match_flags, &ops); > } > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index af017bd8a5477..cb5fbb0279b88 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -30,6 +30,7 @@ > #include <linux/uaccess.h> > #include <linux/perf_event.h> > #include <linux/perf/arm_pmu.h> > +#include <linux/perf/arm_pmuv3.h> > #include <linux/platform_device.h> > #include <linux/pm_runtime.h> > #include <linux/property.h> > @@ -1399,6 +1400,29 @@ static void etm4_fixup_wrong_ccitmin(struct etmv4_caps *caps) > } > } > > +/* > + * Whether the PMU counts each external output of this trace unit as > + * TRCEXTOUTn. The trace unit has an external output for each of its events. > + * Only ETE is checked: per its specification, an implemented TRCEXTOUTn event > + * counts external output n. > + * > + * Must run on the CPU that owns the trace unit. > + */ > +static bool etm4_pmu_counts_extout(struct etmv4_drvdata *drvdata) > +{ > + int n; > + > + if (!etm4x_is_ete(drvdata) || !drvdata->caps.nr_event) > + return false; > + > + for (n = 0; n < drvdata->caps.nr_event; n++) { > + if (!pmuv3_event_implemented(ARMV8_PMUV3_PERFCTR_TRCEXTOUT0 + n)) > + return false; > + } > + > + return true; > +} > + > static void etm4_init_arch_data(void *info) > { > u32 etmidr0; > @@ -1562,6 +1586,8 @@ static void etm4_init_arch_data(void *info) > /* NUMCNTR, bits[30:28] number of counters available for tracing */ > caps->nr_cntr = FIELD_GET(TRCIDR5_NUMCNTR_MASK, etmidr5); > > + caps->trcextout = etm4_pmu_counts_extout(drvdata); > + > coresight_clear_self_claim_tag_unlocked(csa); > etm4_cs_lock(drvdata, csa); > cpu_detect_trace_filtering(drvdata); > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > index 5417280cdb274..33994ad4b2641 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > @@ -868,6 +868,8 @@ enum etm_impdef_type { > * @lpoverride: If the implementation can support low-power state over. > * @skip_power_up: Indicates if an implementation can skip powering up > * the trace unit. > + * @trcextout: The trace unit is an ETE whose PMU counts its external > + * outputs as TRCEXTOUTn. > */ > struct etmv4_caps { > u8 nr_pe; > @@ -907,6 +909,7 @@ struct etmv4_caps { > bool atbtrig : 1; > bool lpoverride : 1; > bool skip_power_up : 1; > + bool trcextout : 1; > }; > > /** > diff --git a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c > index 2b40e556be872..7b3800138f625 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg-configfs.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg-configfs.c > @@ -250,6 +250,9 @@ static ssize_t cscfg_feat_matches_show(struct config_item *item, char *page) > if (match_flags & CS_CFG_MATCH_CLASS_SRC_ETM4) > used += scnprintf(page + used, PAGE_SIZE - used, "SRC_ETMV4 "); > > + if (match_flags & CS_CFG_MATCH_CAP_TRCEXTOUT) > + used += scnprintf(page + used, PAGE_SIZE - used, "TRCEXTOUT "); > + > used += scnprintf(page + used, PAGE_SIZE - used, "\n"); > return used; > } Reviewed-by: James Clark <james.clark(a)linaro.org>

1 week, 1 day

Re: [PATCH v4 5/7] perf: arm_pmuv3: Add pmuv3_event_implemented()

by James Clark

On 26/10/2026 05:48, Amir Ayupov wrote: > Drivers outside the PMU driver may need to know whether the local CPU's > PMU implements a common event before relying on it, for example a trace > unit driver checking that the PMU counts its external outputs as > TRCEXTOUTn. > > Add pmuv3_event_implemented() to the arm64 asm/arm_pmuv3.h, next to > read_pmceid0() and read_pmceid1(). It reads PMCEID0/1 on the calling CPU: > events 0x0000-0x003f are reported in bits [31:0], and the common events > from ARMV8_PMUV3_EXT_COMMON_EVENT_BASE in bits [63:32] from PMUv3p1. Move > ARMV8_PMUV3_EXT_COMMON_EVENT_BASE next to the event numbers in > linux/perf/arm_pmuv3.h so it is available without CONFIG_ARM_PMU. > > Suggested-by: James Clark <james.clark(a)linaro.org> > Assisted-by: Devmate:Opus-5.5 > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > arch/arm64/include/asm/arm_pmuv3.h | 19 +++++++++++++++++++ > include/linux/perf/arm_pmu.h | 1 - > include/linux/perf/arm_pmuv3.h | 3 +++ > 3 files changed, 22 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/arm_pmuv3.h b/arch/arm64/include/asm/arm_pmuv3.h > index 8a777dec8d88a..acd62c4f16743 100644 > --- a/arch/arm64/include/asm/arm_pmuv3.h > +++ b/arch/arm64/include/asm/arm_pmuv3.h > @@ -173,6 +173,25 @@ static inline bool pmuv3_implemented(int pmuver) > pmuver == ID_AA64DFR0_EL1_PMUVer_NI); > } > > +/* > + * Whether this CPU's PMU implements a common event, as reported by > + * PMCEID{0,1}: events 0x0000-0x003f in bits [31:0], and from PMUv3p1 events > + * 0x4000-0x403f in bits [63:32], which read as zero before PMUv3p1. > + * Must run on the CPU whose PMU is queried. > + */ > +static inline bool pmuv3_event_implemented(u16 event) > +{ > + bool ext = event >= ARMV8_PMUV3_EXT_COMMON_EVENT_BASE; > + u16 id = ext ? event - ARMV8_PMUV3_EXT_COMMON_EVENT_BASE : event; > + u64 pmceid; > + > + if (id >= 64 || !pmuv3_implemented(read_pmuver())) > + return false; > + > + pmceid = id < 32 ? read_pmceid0() : read_pmceid1(); > + return pmceid & BIT_ULL(id % 32 + (ext ? 32 : 0)); > +} > + > static inline bool is_pmuv3p4(int pmuver) > { > return pmuver >= ID_AA64DFR0_EL1_PMUVer_V3P4; > diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h > index 02d2c7f45b527..792283d29d7b5 100644 > --- a/include/linux/perf/arm_pmu.h > +++ b/include/linux/perf/arm_pmu.h > @@ -124,7 +124,6 @@ struct arm_pmu { > u64 reg_brbidr; > #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 > DECLARE_BITMAP(pmceid_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); > -#define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 > DECLARE_BITMAP(pmceid_ext_bitmap, ARMV8_PMUV3_MAX_COMMON_EVENTS); > > /* Only to be used by ACPI probing code */ > diff --git a/include/linux/perf/arm_pmuv3.h b/include/linux/perf/arm_pmuv3.h > index d698efba28a27..c21f185a283d6 100644 > --- a/include/linux/perf/arm_pmuv3.h > +++ b/include/linux/perf/arm_pmuv3.h > @@ -78,6 +78,9 @@ > #define ARMV8_PMUV3_PERFCTR_STALL_SLOT_FRONTEND 0x003E > #define ARMV8_PMUV3_PERFCTR_STALL_SLOT 0x003F > > +/* Base of the common events reported in PMCEID{0,1}[63:32] from PMUv3p1 */ > +#define ARMV8_PMUV3_EXT_COMMON_EVENT_BASE 0x4000 > + > /* Statistical profiling extension microarchitectural events */ > #define ARMV8_SPE_PERFCTR_SAMPLE_POP 0x4000 > #define ARMV8_SPE_PERFCTR_SAMPLE_FEED 0x4001 Reviewed-by: James Clark <james.clark(a)linaro.org>

1 week, 1 day

Re: [PATCH v4 4/7] coresight: syscfg: Remove unused CS_CFG_MATCH_INST_ANY

by James Clark

On 26/10/2026 05:48, Amir Ayupov wrote: > CS_CFG_MATCH_INST_ANY has been defined since the system configuration was > introduced but is not used by any configuration, feature or device. > Remove it. > > Suggested-by: Leo Yan <leo.yan(a)arm.com> > Assisted-by: Devmate:Opus-5.5 > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > drivers/hwtracing/coresight/coresight-config.h | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h > index f04e73b91d9a6..220bc54f8e5e1 100644 > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -39,9 +39,6 @@ > */ > #define CS_CFG_MATCH_CAP_MASK GENMASK_U32(15, 8) > > -/* flags defining device instance matching - used in config match desc data. */ > -#define CS_CFG_MATCH_INST_ANY 0x80000000 /* any instance of a class */ > - > /* > * Limit number of presets in a configuration > * This is related to the number of bits (4) we use to select the preset on Reviewed-by: James Clark <james.clark(a)linaro.org>

1 week, 1 day

Re: [PATCH v4 3/7] coresight: syscfg: Match feature capabilities separately from device class

by James Clark

On 26/10/2026 05:48, Amir Ayupov wrote: > A feature loads on a device when the two share any match flag. That works > for device classes, where a feature wants any one of them, but not for > capabilities a device may or may not have: a feature that sets a class > and a capability would still load on a device of that class without the > capability. > > Split the match flags into CS_CFG_MATCH_CLASS_MASK for device classes and > CS_CFG_MATCH_CAP_MASK for capabilities. A feature now loads on a device > that shares one of its classes and has all of its capabilities. Check > this once in cscfg_load_feat_csdev(), which both the feature and the > device registration paths call. No capability flags are defined yet, so > matching is unchanged. > > Assisted-by: Devmate:Opus-5.5 > Signed-off-by: Amir Ayupov <aaupov(a)fb.com> > --- > .../hwtracing/coresight/coresight-config.h | 8 ++++ > .../hwtracing/coresight/coresight-syscfg.c | 37 +++++++++++++------ > 2 files changed, 34 insertions(+), 11 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h > index ae6295e308131..f04e73b91d9a6 100644 > --- a/drivers/hwtracing/coresight/coresight-config.h > +++ b/drivers/hwtracing/coresight/coresight-config.h > @@ -7,6 +7,7 @@ > #ifndef _CORESIGHT_CORESIGHT_CONFIG_H > #define _CORESIGHT_CORESIGHT_CONFIG_H > > +#include <linux/bits.h> > #include <linux/cleanup.h> > #include <linux/coresight.h> > #include <linux/types.h> > @@ -30,6 +31,13 @@ > */ > #define CS_CFG_MATCH_CLASS_SRC_ALL 0x0001 /* match any source */ > #define CS_CFG_MATCH_CLASS_SRC_ETM4 0x0002 /* match any ETMv4 device */ > +#define CS_CFG_MATCH_CLASS_MASK GENMASK_U32(7, 0) > + > +/* > + * flags defining device capabilities a feature can require. A feature loads on > + * a device that matches one of its classes and has all of its capabilities. > + */ > +#define CS_CFG_MATCH_CAP_MASK GENMASK_U32(15, 8) > > /* flags defining device instance matching - used in config match desc data. */ > #define CS_CFG_MATCH_INST_ANY 0x80000000 /* any instance of a class */ > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c > index a816c22c87bc8..3ee104e94a4cd 100644 > --- a/drivers/hwtracing/coresight/coresight-syscfg.c > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c > @@ -171,8 +171,22 @@ cscfg_alloc_csdev_feat(struct coresight_device *csdev, struct cscfg_feature_desc > return feat_csdev; > } > > -/* load one feature into one coresight device */ > +static bool cscfg_match_feat_csdev(u32 feat_flags, u32 csdev_flags) > +{ > + /* The device must be in one of the feature's classes */ > + if (!(feat_flags & csdev_flags & CS_CFG_MATCH_CLASS_MASK)) > + return false; > + > + /* The device must have every capability the feature requires */ > + if (feat_flags & ~csdev_flags & CS_CFG_MATCH_CAP_MASK) > + return false; > + > + return true; > +} > + > +/* Load the feature into the device if it matches, otherwise skip it. */ > static int cscfg_load_feat_csdev(struct coresight_device *csdev, > + u32 match_flags, > struct cscfg_feature_desc *feat_desc, > struct cscfg_csdev_feat_ops *ops) > { > @@ -183,6 +197,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev, > if (!ops->load_feat) > return -EINVAL; > > + if (!cscfg_match_feat_csdev(feat_desc->match_flags, match_flags)) > + return 0; > + > feat_csdev = cscfg_alloc_csdev_feat(csdev, feat_desc); > if (!feat_csdev) > return -ENOMEM; > @@ -212,11 +229,11 @@ static int cscfg_add_feat_to_csdevs(struct cscfg_feature_desc *feat_desc) > int err; > > list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) { > - if (csdev_item->match_flags & feat_desc->match_flags) { > - err = cscfg_load_feat_csdev(csdev_item->csdev, feat_desc, &csdev_item->ops); > - if (err) > - return err; > - } > + err = cscfg_load_feat_csdev(csdev_item->csdev, > + csdev_item->match_flags, feat_desc, > + &csdev_item->ops); > + if (err) > + return err; > } > return 0; > } > @@ -739,11 +756,9 @@ static int cscfg_add_feats_csdev(struct coresight_device *csdev, > return -EINVAL; > > list_for_each_entry(feat_desc, &cscfg_mgr->feat_desc_list, item) { > - if (feat_desc->match_flags & match_flags) { > - err = cscfg_load_feat_csdev(csdev, feat_desc, ops); > - if (err) > - break; > - } > + err = cscfg_load_feat_csdev(csdev, match_flags, feat_desc, ops); > + if (err) > + break; > } > return err; > } Reviewed-by: James Clark <james.clark(a)linaro.org>

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