[PATCH v8 05/23] coresight: Move per-CPU source pointer to core layer
Leo Yan
leo.yan at arm.com
Wed Mar 25 07:26:42 PDT 2026
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.
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
drivers/hwtracing/coresight/coresight-core.c | 32 ++++++++++++++++++++++++
drivers/hwtracing/coresight/coresight-etm-perf.c | 21 +++++++---------
drivers/hwtracing/coresight/coresight-priv.h | 1 +
3 files changed, 42 insertions(+), 12 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 6907da35ed02fa58f8d30f5576627a6ce3b88362..93acbd36c9c0efcc311c5374463b2ae9a4e6e49b 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -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 +85,33 @@ 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);
+ 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);
+ 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);
+}
+
static struct coresight_device *coresight_get_source(struct coresight_path *path)
{
struct coresight_device *csdev;
@@ -1422,6 +1452,7 @@ 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)
@@ -1451,6 +1482,7 @@ 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);
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index cae6738e9906c35d291e4b0f3feae37306b95c06..a2c1c876099d1f5dacf039d733b78827296d9c2e 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -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);
@@ -356,7 +355,7 @@ 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
@@ -479,10 +478,11 @@ static void etm_event_start(struct perf_event *event, int flags)
struct etm_event_data *event_data;
struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
struct perf_output_handle *handle = &ctxt->handle;
- struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
+ struct coresight_device *sink, *csdev;
struct coresight_path *path;
u64 hw_id;
+ csdev = coresight_get_percpu_source(cpu);
if (!csdev)
goto fail;
@@ -630,12 +630,14 @@ static void etm_event_stop(struct perf_event *event, int mode)
{
int cpu = smp_processor_id();
unsigned long size;
- struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
+ struct coresight_device *sink, *csdev;
struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
struct perf_output_handle *handle = &ctxt->handle;
struct etm_event_data *event_data;
struct coresight_path *path;
+ csdev = coresight_get_percpu_source(cpu);
+
if (mode & PERF_EF_PAUSE)
return etm_event_pause(event, csdev, ctxt);
@@ -833,17 +835,12 @@ 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);
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 1ea882dffd703b2873e41b4ce0c2564d2ce9bbad..c96d63657f9334be890cca2320abbb8cbd807802 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -248,6 +248,7 @@ 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_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);
--
2.34.1
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