diff options
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etm-perf.c | 31 | ||||
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-priv.h | 4 | ||||
| -rw-r--r-- | drivers/hwtracing/coresight/coresight.c | 74 |
3 files changed, 87 insertions, 22 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 2cd7c718198a..5a346fc8ce06 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -202,6 +202,21 @@ static void *etm_setup_aux(int event_cpu, void **pages, if (!event_data) return NULL; + /* + * In theory nothing prevent tracers in a trace session from being + * associated with different sinks, nor having a sink per tracer. But + * until we have HW with this kind of topology we need to assume tracers + * in a trace session are using the same sink. Therefore go through + * the coresight bus and pick the first enabled sink. + * + * When operated from sysFS users are responsible to enable the sink + * while from perf, the perf tools will do it based on the choice made + * on the cmd line. As such the "enable_sink" flag in sysFS is reset. + */ + sink = coresight_get_enabled_sink(true); + if (!sink) + return NULL; + INIT_WORK(&event_data->work, free_event_data); mask = &event_data->mask; @@ -219,25 +234,11 @@ static void *etm_setup_aux(int event_cpu, void **pages, * list of devices from source to sink that can be * referenced later when the path is actually needed. */ - event_data->path[cpu] = coresight_build_path(csdev); + event_data->path[cpu] = coresight_build_path(csdev, sink); if (IS_ERR(event_data->path[cpu])) goto err; } - /* - * In theory nothing prevent tracers in a trace session from being - * associated with different sinks, nor having a sink per tracer. But - * until we have HW with this kind of topology and a way to convey - * sink assignement from the perf cmd line we need to assume tracers - * in a trace session are using the same sink. Therefore pick the sink - * found at the end of the first available path. - */ - cpu = cpumask_first(mask); - /* Grab the sink at the end of the path */ - sink = coresight_get_sink(event_data->path[cpu]); - if (!sink) - goto err; - if (!sink_ops(sink)->alloc_buffer) goto err; diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 196a14be4b3d..ef9d8e93e3b2 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -111,7 +111,9 @@ static inline void CS_UNLOCK(void __iomem *addr) void coresight_disable_path(struct list_head *path); int coresight_enable_path(struct list_head *path, u32 mode); struct coresight_device *coresight_get_sink(struct list_head *path); -struct list_head *coresight_build_path(struct coresight_device *csdev); +struct coresight_device *coresight_get_enabled_sink(bool reset); +struct list_head *coresight_build_path(struct coresight_device *csdev, + struct coresight_device *sink); void coresight_release_path(struct list_head *path); #ifdef CONFIG_CORESIGHT_SOURCE_ETM3X diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 7bf00a0beb6f..0c37356e417c 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -368,6 +368,52 @@ struct coresight_device *coresight_get_sink(struct list_head *path) return csdev; } +static int coresight_enabled_sink(struct device *dev, void *data) +{ + bool *reset = data; + struct coresight_device *csdev = to_coresight_device(dev); + + if ((csdev->type == CORESIGHT_DEV_TYPE_SINK || + csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) && + csdev->activated) { + /* + * Now that we have a handle on the sink for this session, + * disable the sysFS "enable_sink" flag so that possible + * concurrent perf session that wish to use another sink don't + * trip on it. Doing so has no ramification for the current + * session. + */ + if (*reset) + csdev->activated = false; + + return 1; + } + + return 0; +} + +/** + * coresight_get_enabled_sink - returns the first enabled sink found on the bus + * @deactivate: Whether the 'enable_sink' flag should be reset + * + * When operated from perf the deactivate parameter should be set to 'true'. + * That way the "enabled_sink" flag of the sink that was selected can be reset, + * allowing for other concurrent perf sessions to choose a different sink. + * + * When operated from sysFS users have full control and as such the deactivate + * parameter should be set to 'false', hence mandating users to explicitly + * clear the flag. + */ +struct coresight_device *coresight_get_enabled_sink(bool deactivate) +{ + struct device *dev = NULL; + + dev = bus_find_device(&coresight_bustype, NULL, &deactivate, + coresight_enabled_sink); + + return dev ? to_coresight_device(dev) : NULL; +} + /** * _coresight_build_path - recursively build a path from a @csdev to a sink. * @csdev: The device to start from. @@ -380,6 +426,7 @@ struct coresight_device *coresight_get_sink(struct list_head *path) * last one. */ static int _coresight_build_path(struct coresight_device *csdev, + struct coresight_device *sink, struct list_head *path) { int i; @@ -387,15 +434,15 @@ static int _coresight_build_path(struct coresight_device *csdev, struct coresight_node *node; /* An activated sink has been found. Enqueue the element */ - if ((csdev->type == CORESIGHT_DEV_TYPE_SINK || - csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) && csdev->activated) + if (csdev == sink) goto out; /* Not a sink - recursively explore each port found on this element */ for (i = 0; i < csdev->nr_outport; i++) { struct coresight_device *child_dev = csdev->conns[i].child_dev; - if (child_dev && _coresight_build_path(child_dev, path) == 0) { + if (child_dev && + _coresight_build_path(child_dev, sink, path) == 0) { found = true; break; } @@ -422,18 +469,22 @@ out: return 0; } -struct list_head *coresight_build_path(struct coresight_device *csdev) +struct list_head *coresight_build_path(struct coresight_device *source, + struct coresight_device *sink) { struct list_head *path; int rc; + if (!sink) + return ERR_PTR(-EINVAL); + path = kzalloc(sizeof(struct list_head), GFP_KERNEL); if (!path) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(path); - rc = _coresight_build_path(csdev, path); + rc = _coresight_build_path(source, sink, path); if (rc) { kfree(path); return ERR_PTR(rc); @@ -497,6 +548,7 @@ static int coresight_validate_source(struct coresight_device *csdev, int coresight_enable(struct coresight_device *csdev) { int cpu, ret = 0; + struct coresight_device *sink; struct list_head *path; mutex_lock(&coresight_mutex); @@ -508,7 +560,17 @@ int coresight_enable(struct coresight_device *csdev) if (csdev->enable) goto out; - path = coresight_build_path(csdev); + /* + * Search for a valid sink for this session but don't reset the + * "enable_sink" flag in sysFS. Users get to do that explicitly. + */ + sink = coresight_get_enabled_sink(false); + if (!sink) { + ret = -EINVAL; + goto out; + } + + path = coresight_build_path(csdev, sink); if (IS_ERR(path)) { pr_err("building path(s) failed\n"); ret = PTR_ERR(path); |