Add coresight_set_percpu_source() to set the CPU source device. Source devices are stored in the per-CPU structure csdev_source.
When the CPU is online, set the per-CPU pointer on the local CPU to avoid race conditions between setting and fetching the same pointer.
Reviewed-by: Mike Leach mike.leach@linaro.org Tested-by: James Clark james.clark@linaro.org Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-core.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 0c48f5c85db6a7ec0377335eaa734527959d57c4..f22fd89f29b97ffe7004a2c988b09d5fd412af8d 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -34,6 +34,7 @@ */ DEFINE_MUTEX(coresight_mutex); static DEFINE_PER_CPU(struct coresight_device *, csdev_sink); +static DEFINE_PER_CPU(struct coresight_device *, csdev_source);
/** * struct coresight_node - elements of a path, from source to sink @@ -79,6 +80,22 @@ struct coresight_device *coresight_get_percpu_sink(int cpu) } EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
+static void coresight_set_percpu_source_local(void *csdev) +{ + this_cpu_write(csdev_source, csdev); +} + +static void coresight_set_percpu_source(int cpu, struct coresight_device *csdev) +{ + cpus_read_lock(); + if (cpu_online(cpu)) + smp_call_function_single(cpu, coresight_set_percpu_source_local, + csdev, 1); + else + per_cpu(csdev_source, cpu) = csdev; + cpus_read_unlock(); +} + static struct coresight_device *coresight_get_source(struct coresight_path *path) { struct coresight_device *csdev; @@ -1397,6 +1414,10 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) goto out_unlock; } } + + if (coresight_is_percpu_source(csdev)) + coresight_set_percpu_source(csdev->cpu, csdev); + /* Device is now registered */ registered = true;
@@ -1428,6 +1449,8 @@ EXPORT_SYMBOL_GPL(coresight_register);
void coresight_unregister(struct coresight_device *csdev) { + if (coresight_is_percpu_source(csdev)) + coresight_set_percpu_source(csdev->cpu, NULL); etm_perf_del_symlink_sink(csdev); /* Remove references of that device in the topology */ if (cti_assoc_ops && cti_assoc_ops->remove)