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coresight: Move per-CPU source pointer to core layer

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Move the per-CPU source pointer from ETM perf to the core layer, as this
will be used for not only perf session and also for CPU PM notifiers.

Provides coresight_{set|clear|get}_percpu_source() helpers to access the
per-CPU source pointer. Add a raw spinlock to protect exclusive access.

Device registration and unregistration call the set and clear helpers
for init and teardown the pointers.

Update callers to invoke coresight_get_percpu_source() for retrieving
the pointer.

Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-9-f88c4a3ecfe9@arm.com
This commit is contained in:
Leo Yan 2026-05-15 21:08:16 +01:00 committed by Suzuki K Poulose
parent 6317302ae2
commit 3a4a1c4dd9
3 changed files with 43 additions and 10 deletions
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38
drivers/hwtracing/coresight/coresight-core.c
View File

@ -35,6 +35,9 @@
DEFINE_MUTEX(coresight_mutex);
static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
static DEFINE_RAW_SPINLOCK(coresight_dev_lock);
static DEFINE_PER_CPU(struct coresight_device *, csdev_source);
/**
* struct coresight_node - elements of a path, from source to sink
* @csdev: Address of an element.
@ -82,6 +85,39 @@ struct coresight_device *coresight_get_percpu_sink(int cpu)
}
EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
static void coresight_set_percpu_source(struct coresight_device *csdev)
{
if (!csdev || !coresight_is_percpu_source(csdev))
return;
guard(raw_spinlock_irqsave)(&coresight_dev_lock);
/* Expect no device to be set yet */
WARN_ON(per_cpu(csdev_source, csdev->cpu));
per_cpu(csdev_source, csdev->cpu) = csdev;
}
static void coresight_clear_percpu_source(struct coresight_device *csdev)
{
if (!csdev || !coresight_is_percpu_source(csdev))
return;
guard(raw_spinlock_irqsave)(&coresight_dev_lock);
/* The per-CPU pointer should contain the same csdev */
WARN_ON(per_cpu(csdev_source, csdev->cpu) != csdev);
per_cpu(csdev_source, csdev->cpu) = NULL;
}
struct coresight_device *coresight_get_percpu_source(int cpu)
{
if (WARN_ON(cpu < 0))
return NULL;
guard(raw_spinlock_irqsave)(&coresight_dev_lock);
return per_cpu(csdev_source, cpu);
}
struct coresight_device *coresight_get_source(struct coresight_path *path)
{
struct coresight_device *csdev;
@ -1452,6 +1488,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
if (ret)
goto out_unlock;
coresight_set_percpu_source(csdev);
mutex_unlock(&coresight_mutex);
if (cti_assoc_ops && cti_assoc_ops->add)
@ -1481,6 +1518,7 @@ void coresight_unregister(struct coresight_device *csdev)
cti_assoc_ops->remove(csdev);
mutex_lock(&coresight_mutex);
coresight_clear_percpu_source(csdev);
etm_perf_del_symlink_sink(csdev);
coresight_remove_conns(csdev);
coresight_clear_default_sink(csdev);

14
drivers/hwtracing/coresight/coresight-etm-perf.c
View File

@ -49,7 +49,6 @@ struct etm_ctxt {
};
static DEFINE_PER_CPU(struct etm_ctxt, etm_ctxt);
static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
GEN_PMU_FORMAT_ATTR(cycacc);
GEN_PMU_FORMAT_ATTR(timestamp);
@ -386,7 +385,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
struct coresight_path *path;
struct coresight_device *csdev;
csdev = per_cpu(csdev_src, cpu);
csdev = coresight_get_percpu_source(cpu);
/*
* If there is no ETM associated with this CPU clear it from
* the mask and continue with the rest. If ever we try to trace
@ -864,17 +863,12 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link)
if (!etm_perf_up)
return -EPROBE_DEFER;
if (link) {
if (link)
ret = sysfs_create_link(&pmu_dev->kobj, &cs_dev->kobj, entry);
if (ret)
return ret;
per_cpu(csdev_src, cpu) = csdev;
} else {
else
sysfs_remove_link(&pmu_dev->kobj, entry);
per_cpu(csdev_src, cpu) = NULL;
}
return 0;
return ret;
}
EXPORT_SYMBOL_GPL(etm_perf_symlink);

1
drivers/hwtracing/coresight/coresight-priv.h
View File

@ -249,6 +249,7 @@ void coresight_add_helper(struct coresight_device *csdev,
void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
struct coresight_device *coresight_get_percpu_sink(int cpu);
struct coresight_device *coresight_get_source(struct coresight_path *path);
struct coresight_device *coresight_get_percpu_source(int cpu);
void coresight_disable_source(struct coresight_device *csdev, void *data);
void coresight_pause_source(struct coresight_device *csdev);
int coresight_resume_source(struct coresight_device *csdev);