1 files changed, 329 insertions, 54 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 84f1dcb69827..43bbd5dc3d3b 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -18,29 +18,87 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
+#include "coresight-config.h"
 #include "coresight-etm-perf.h"
 #include "coresight-priv.h"
+#include "coresight-syscfg.h"
 
 static struct pmu etm_pmu;
 static bool etm_perf_up;
 
-static DEFINE_PER_CPU(struct perf_output_handle, ctx_handle);
+/*
+ * An ETM context for a running event includes the perf aux handle
+ * and aux_data. For ETM, the aux_data (etm_event_data), consists of
+ * the trace path and the sink configuration. The event data is accessible
+ * via perf_get_aux(handle). However, a sink could "end" a perf output
+ * handle via the IRQ handler. And if the "sink" encounters a failure
+ * to "begin" another session (e.g due to lack of space in the buffer),
+ * the handle will be cleared. Thus, the event_data may not be accessible
+ * from the handle when we get to the etm_event_stop(), which is required
+ * for stopping the trace path. The event_data is guaranteed to stay alive
+ * until "free_aux()", which cannot happen as long as the event is active on
+ * the ETM. Thus the event_data for the session must be part of the ETM context
+ * to make sure we can disable the trace path.
+ */
+struct etm_ctxt {
+	struct perf_output_handle handle;
+	struct etm_event_data *event_data;
+};
+
+static DEFINE_PER_CPU(struct etm_ctxt, etm_ctxt);
 static DEFINE_PER_CPU(struct coresight_device *, csdev_src);
 
-/* ETMv3.5/PTM's ETMCR is 'config' */
+/*
+ * The PMU formats were orignally for ETMv3.5/PTM's ETMCR 'config';
+ * now take them as general formats and apply on all ETMs.
+ */
+PMU_FORMAT_ATTR(branch_broadcast, "config:"__stringify(ETM_OPT_BRANCH_BROADCAST));
 PMU_FORMAT_ATTR(cycacc,		"config:" __stringify(ETM_OPT_CYCACC));
-PMU_FORMAT_ATTR(contextid,	"config:" __stringify(ETM_OPT_CTXTID));
+/* contextid1 enables tracing CONTEXTIDR_EL1 for ETMv4 */
+PMU_FORMAT_ATTR(contextid1,	"config:" __stringify(ETM_OPT_CTXTID));
+/* contextid2 enables tracing CONTEXTIDR_EL2 for ETMv4 */
+PMU_FORMAT_ATTR(contextid2,	"config:" __stringify(ETM_OPT_CTXTID2));
 PMU_FORMAT_ATTR(timestamp,	"config:" __stringify(ETM_OPT_TS));
 PMU_FORMAT_ATTR(retstack,	"config:" __stringify(ETM_OPT_RETSTK));
+/* preset - if sink ID is used as a configuration selector */
+PMU_FORMAT_ATTR(preset,		"config:0-3");
 /* Sink ID - same for all ETMs */
 PMU_FORMAT_ATTR(sinkid,		"config2:0-31");
+/* config ID - set if a system configuration is selected */
+PMU_FORMAT_ATTR(configid,	"config2:32-63");
+
+
+/*
+ * contextid always traces the "PID".  The PID is in CONTEXTIDR_EL1
+ * when the kernel is running at EL1; when the kernel is at EL2,
+ * the PID is in CONTEXTIDR_EL2.
+ */
+static ssize_t format_attr_contextid_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *page)
+{
+	int pid_fmt = ETM_OPT_CTXTID;
+
+#if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM4X)
+	pid_fmt = is_kernel_in_hyp_mode() ? ETM_OPT_CTXTID2 : ETM_OPT_CTXTID;
+#endif
+	return sprintf(page, "config:%d\n", pid_fmt);
+}
+
+static struct device_attribute format_attr_contextid =
+	__ATTR(contextid, 0444, format_attr_contextid_show, NULL);
 
 static struct attribute *etm_config_formats_attr[] = {
 	&format_attr_cycacc.attr,
 	&format_attr_contextid.attr,
+	&format_attr_contextid1.attr,
+	&format_attr_contextid2.attr,
 	&format_attr_timestamp.attr,
 	&format_attr_retstack.attr,
 	&format_attr_sinkid.attr,
+	&format_attr_preset.attr,
+	&format_attr_configid.attr,
+	&format_attr_branch_broadcast.attr,
 	NULL,
 };
 
@@ -58,9 +116,19 @@ static const struct attribute_group etm_pmu_sinks_group = {
 	.attrs  = etm_config_sinks_attr,
 };
 
+static struct attribute *etm_config_events_attr[] = {
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_events_group = {
+	.name   = "events",
+	.attrs  = etm_config_events_attr,
+};
+
 static const struct attribute_group *etm_pmu_attr_groups[] = {
 	&etm_pmu_format_group,
 	&etm_pmu_sinks_group,
+	&etm_pmu_events_group,
 	NULL,
 };
 
@@ -126,10 +194,10 @@ static void free_sink_buffer(struct etm_event_data *event_data)
 	cpumask_t *mask = &event_data->mask;
 	struct coresight_device *sink;
 
-	if (WARN_ON(cpumask_empty(mask)))
+	if (!event_data->snk_config)
 		return;
 
-	if (!event_data->snk_config)
+	if (WARN_ON(cpumask_empty(mask)))
 		return;
 
 	cpu = cpumask_first(mask);
@@ -149,6 +217,10 @@ static void free_event_data(struct work_struct *work)
 	/* Free the sink buffers, if there are any */
 	free_sink_buffer(event_data);
 
+	/* clear any configuration we were using */
+	if (event_data->cfg_hash)
+		cscfg_deactivate_config(event_data->cfg_hash);
+
 	for_each_cpu(cpu, mask) {
 		struct list_head **ppath;
 
@@ -204,13 +276,33 @@ static void etm_free_aux(void *data)
 	schedule_work(&event_data->work);
 }
 
+/*
+ * Check if two given sinks are compatible with each other,
+ * so that they can use the same sink buffers, when an event
+ * moves around.
+ */
+static bool sinks_compatible(struct coresight_device *a,
+			     struct coresight_device *b)
+{
+	if (!a || !b)
+		return false;
+	/*
+	 * If the sinks are of the same subtype and driven
+	 * by the same driver, we can use the same buffer
+	 * on these sinks.
+	 */
+	return (a->subtype.sink_subtype == b->subtype.sink_subtype) &&
+	       (sink_ops(a) == sink_ops(b));
+}
+
 static void *etm_setup_aux(struct perf_event *event, void **pages,
 			   int nr_pages, bool overwrite)
 {
-	u32 id;
+	u32 id, cfg_hash;
 	int cpu = event->cpu;
 	cpumask_t *mask;
-	struct coresight_device *sink;
+	struct coresight_device *sink = NULL;
+	struct coresight_device *user_sink = NULL, *last_sink = NULL;
 	struct etm_event_data *event_data = NULL;
 
 	event_data = alloc_event_data(cpu);
@@ -219,15 +311,18 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	INIT_WORK(&event_data->work, free_event_data);
 
 	/* First get the selected sink from user space. */
-	if (event->attr.config2) {
+	if (event->attr.config2 & GENMASK_ULL(31, 0)) {
 		id = (u32)event->attr.config2;
-		sink = coresight_get_sink_by_id(id);
-	} else {
-		sink = coresight_get_enabled_sink(true);
+		sink = user_sink = coresight_get_sink_by_id(id);
 	}
 
-	if (!sink)
-		goto err;
+	/* check if user wants a coresight configuration selected */
+	cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
+	if (cfg_hash) {
+		if (cscfg_activate_config(cfg_hash))
+			goto err;
+		event_data->cfg_hash = cfg_hash;
+	}
 
 	mask = &event_data->mask;
 
@@ -254,6 +349,35 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 		}
 
 		/*
+		 * No sink provided - look for a default sink for all the ETMs,
+		 * where this event can be scheduled.
+		 * We allocate the sink specific buffers only once for this
+		 * event. If the ETMs have different default sink devices, we
+		 * can only use a single "type" of sink as the event can carry
+		 * only one sink specific buffer. Thus we have to make sure
+		 * that the sinks are of the same type and driven by the same
+		 * driver, as the one we allocate the buffer for. As such
+		 * we choose the first sink and check if the remaining ETMs
+		 * have a compatible default sink. We don't trace on a CPU
+		 * if the sink is not compatible.
+		 */
+		if (!user_sink) {
+			/* Find the default sink for this ETM */
+			sink = coresight_find_default_sink(csdev);
+			if (!sink) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+
+			/* Check if this sink compatible with the last sink */
+			if (last_sink && !sinks_compatible(last_sink, sink)) {
+				cpumask_clear_cpu(cpu, mask);
+				continue;
+			}
+			last_sink = sink;
+		}
+
+		/*
 		 * Building a path doesn't enable it, it simply builds a
 		 * list of devices from source to sink that can be
 		 * referenced later when the path is actually needed.
@@ -267,6 +391,10 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 		*etm_event_cpu_path_ptr(event_data, cpu) = path;
 	}
 
+	/* no sink found for any CPU - cannot trace */
+	if (!sink)
+		goto err;
+
 	/* If we don't have any CPUs ready for tracing, abort */
 	cpu = cpumask_first(mask);
 	if (cpu >= nr_cpu_ids)
@@ -275,7 +403,12 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 	if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer)
 		goto err;
 
-	/* Allocate the sink buffer for this session */
+	/*
+	 * Allocate the sink buffer for this session. All the sinks
+	 * where this event can be scheduled are ensured to be of the
+	 * same type. Thus the same sink configuration is used by the
+	 * sinks.
+	 */
 	event_data->snk_config =
 			sink_ops(sink)->alloc_buffer(sink, event, pages,
 						     nr_pages, overwrite);
@@ -295,13 +428,18 @@ static void etm_event_start(struct perf_event *event, int flags)
 {
 	int cpu = smp_processor_id();
 	struct etm_event_data *event_data;
-	struct perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
+	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 list_head *path;
 
 	if (!csdev)
 		goto fail;
 
+	/* Have we messed up our tracking ? */
+	if (WARN_ON(ctxt->event_data))
+		goto fail;
+
 	/*
 	 * Deal with the ring buffer API and get a handle on the
 	 * session's information.
@@ -310,6 +448,21 @@ static void etm_event_start(struct perf_event *event, int flags)
 	if (!event_data)
 		goto fail;
 
+	/*
+	 * Check if this ETM is allowed to trace, as decided
+	 * at etm_setup_aux(). This could be due to an unreachable
+	 * sink from this ETM. We can't do much in this case if
+	 * the sink was specified or hinted to the driver. For
+	 * now, simply don't record anything on this ETM.
+	 *
+	 * As such we pretend that everything is fine, and let
+	 * it continue without actually tracing. The event could
+	 * continue tracing when it moves to a CPU where it is
+	 * reachable to a sink.
+	 */
+	if (!cpumask_test_cpu(cpu, &event_data->mask))
+		goto out;
+
 	path = etm_event_cpu_path(event_data, cpu);
 	/* We need a sink, no need to continue without one */
 	sink = coresight_get_sink(path);
@@ -320,24 +473,32 @@ static void etm_event_start(struct perf_event *event, int flags)
 	if (coresight_enable_path(path, CS_MODE_PERF, handle))
 		goto fail_end_stop;
 
-	/* Tell the perf core the event is alive */
-	event->hw.state = 0;
-
 	/* Finally enable the tracer */
 	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
 		goto fail_disable_path;
 
 out:
+	/* Tell the perf core the event is alive */
+	event->hw.state = 0;
+	/* Save the event_data for this ETM */
+	ctxt->event_data = event_data;
 	return;
 
 fail_disable_path:
 	coresight_disable_path(path);
 fail_end_stop:
-	perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
-	perf_aux_output_end(handle, 0);
+	/*
+	 * Check if the handle is still associated with the event,
+	 * to handle cases where if the sink failed to start the
+	 * trace and TRUNCATED the handle already.
+	 */
+	if (READ_ONCE(handle->event)) {
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+		perf_aux_output_end(handle, 0);
+	}
 fail:
 	event->hw.state = PERF_HES_STOPPED;
-	goto out;
+	return;
 }
 
 static void etm_event_stop(struct perf_event *event, int mode)
@@ -345,13 +506,43 @@ 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 perf_output_handle *handle = this_cpu_ptr(&ctx_handle);
-	struct etm_event_data *event_data = perf_get_aux(handle);
+	struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt);
+	struct perf_output_handle *handle = &ctxt->handle;
+	struct etm_event_data *event_data;
 	struct list_head *path;
 
+	/*
+	 * If we still have access to the event_data via handle,
+	 * confirm that we haven't messed up the tracking.
+	 */
+	if (handle->event &&
+	    WARN_ON(perf_get_aux(handle) != ctxt->event_data))
+		return;
+
+	event_data = ctxt->event_data;
+	/* Clear the event_data as this ETM is stopping the trace. */
+	ctxt->event_data = NULL;
+
 	if (event->hw.state == PERF_HES_STOPPED)
 		return;
 
+	/* We must have a valid event_data for a running event */
+	if (WARN_ON(!event_data))
+		return;
+
+	/*
+	 * Check if this ETM was allowed to trace, as decided at
+	 * etm_setup_aux(). If it wasn't allowed to trace, then
+	 * nothing needs to be torn down other than outputting a
+	 * zero sized record.
+	 */
+	if (handle->event && (mode & PERF_EF_UPDATE) &&
+	    !cpumask_test_cpu(cpu, &event_data->mask)) {
+		event->hw.state = PERF_HES_STOPPED;
+		perf_aux_output_end(handle, 0);
+		return;
+	}
+
 	if (!csdev)
 		return;
 
@@ -369,7 +560,13 @@ static void etm_event_stop(struct perf_event *event, int mode)
 	/* tell the core */
 	event->hw.state = PERF_HES_STOPPED;
 
-	if (mode & PERF_EF_UPDATE) {
+	/*
+	 * If the handle is not bound to an event anymore
+	 * (e.g, the sink driver was unable to restart the
+	 * handle due to lack of buffer space), we don't
+	 * have to do anything here.
+	 */
+	if (handle->event && (mode & PERF_EF_UPDATE)) {
 		if (WARN_ON_ONCE(handle->event != event))
 			return;
 
@@ -379,7 +576,21 @@ static void etm_event_stop(struct perf_event *event, int mode)
 
 		size = sink_ops(sink)->update_buffer(sink, handle,
 					      event_data->snk_config);
-		perf_aux_output_end(handle, size);
+		/*
+		 * Make sure the handle is still valid as the
+		 * sink could have closed it from an IRQ.
+		 * The sink driver must handle the race with
+		 * update_buffer() and IRQ. Thus either we
+		 * should get a valid handle and valid size
+		 * (which may be 0).
+		 *
+		 * But we should never get a non-zero size with
+		 * an invalid handle.
+		 */
+		if (READ_ONCE(handle->event))
+			perf_aux_output_end(handle, size);
+		else
+			WARN_ON(size);
 	}
 
 	/* Disabling the path make its elements available to other sessions */
@@ -506,6 +717,7 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(etm_perf_symlink);
 
 static ssize_t etm_perf_sink_name_show(struct device *dev,
 				       struct device_attribute *dattr,
@@ -517,69 +729,128 @@ static ssize_t etm_perf_sink_name_show(struct device *dev,
 	return scnprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)(ea->var));
 }
 
-int etm_perf_add_symlink_sink(struct coresight_device *csdev)
+static struct dev_ext_attribute *
+etm_perf_add_symlink_group(struct device *dev, const char *name, const char *group_name)
 {
-	int ret;
+	struct dev_ext_attribute *ea;
 	unsigned long hash;
-	const char *name;
+	int ret;
 	struct device *pmu_dev = etm_pmu.dev;
-	struct device *dev = &csdev->dev;
-	struct dev_ext_attribute *ea;
-
-	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
-	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
-		return -EINVAL;
-
-	if (csdev->ea != NULL)
-		return -EINVAL;
 
 	if (!etm_perf_up)
-		return -EPROBE_DEFER;
+		return ERR_PTR(-EPROBE_DEFER);
 
 	ea = devm_kzalloc(dev, sizeof(*ea), GFP_KERNEL);
 	if (!ea)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	name = dev_name(dev);
-	/* See function coresight_get_sink_by_id() to know where this is used */
+	/*
+	 * If this function is called adding a sink then the hash is used for
+	 * sink selection - see function coresight_get_sink_by_id().
+	 * If adding a configuration then the hash is used for selection in
+	 * cscfg_activate_config()
+	 */
 	hash = hashlen_hash(hashlen_string(NULL, name));
 
 	sysfs_attr_init(&ea->attr.attr);
 	ea->attr.attr.name = devm_kstrdup(dev, name, GFP_KERNEL);
 	if (!ea->attr.attr.name)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	ea->attr.attr.mode = 0444;
-	ea->attr.show = etm_perf_sink_name_show;
 	ea->var = (unsigned long *)hash;
 
 	ret = sysfs_add_file_to_group(&pmu_dev->kobj,
-				      &ea->attr.attr, "sinks");
+				      &ea->attr.attr, group_name);
 
-	if (!ret)
-		csdev->ea = ea;
+	return ret ? ERR_PTR(ret) : ea;
+}
 
-	return ret;
+int etm_perf_add_symlink_sink(struct coresight_device *csdev)
+{
+	const char *name;
+	struct device *dev = &csdev->dev;
+	int err = 0;
+
+	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+		return -EINVAL;
+
+	if (csdev->ea != NULL)
+		return -EINVAL;
+
+	name = dev_name(dev);
+	csdev->ea = etm_perf_add_symlink_group(dev, name, "sinks");
+	if (IS_ERR(csdev->ea)) {
+		err = PTR_ERR(csdev->ea);
+		csdev->ea = NULL;
+	} else
+		csdev->ea->attr.show = etm_perf_sink_name_show;
+
+	return err;
 }
 
-void etm_perf_del_symlink_sink(struct coresight_device *csdev)
+static void etm_perf_del_symlink_group(struct dev_ext_attribute *ea, const char *group_name)
 {
 	struct device *pmu_dev = etm_pmu.dev;
-	struct dev_ext_attribute *ea = csdev->ea;
 
+	sysfs_remove_file_from_group(&pmu_dev->kobj,
+				     &ea->attr.attr, group_name);
+}
+
+void etm_perf_del_symlink_sink(struct coresight_device *csdev)
+{
 	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
 	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
 		return;
 
-	if (!ea)
+	if (!csdev->ea)
 		return;
 
-	sysfs_remove_file_from_group(&pmu_dev->kobj,
-				     &ea->attr.attr, "sinks");
+	etm_perf_del_symlink_group(csdev->ea, "sinks");
 	csdev->ea = NULL;
 }
 
-static int __init etm_perf_init(void)
+static ssize_t etm_perf_cscfg_event_show(struct device *dev,
+					 struct device_attribute *dattr,
+					 char *buf)
+{
+	struct dev_ext_attribute *ea;
+
+	ea = container_of(dattr, struct dev_ext_attribute, attr);
+	return scnprintf(buf, PAGE_SIZE, "configid=0x%lx\n", (unsigned long)(ea->var));
+}
+
+int etm_perf_add_symlink_cscfg(struct device *dev, struct cscfg_config_desc *config_desc)
+{
+	int err = 0;
+
+	if (config_desc->event_ea != NULL)
+		return 0;
+
+	config_desc->event_ea = etm_perf_add_symlink_group(dev, config_desc->name, "events");
+
+	/* set the show function to the custom cscfg event */
+	if (!IS_ERR(config_desc->event_ea))
+		config_desc->event_ea->attr.show = etm_perf_cscfg_event_show;
+	else {
+		err = PTR_ERR(config_desc->event_ea);
+		config_desc->event_ea = NULL;
+	}
+
+	return err;
+}
+
+void etm_perf_del_symlink_cscfg(struct cscfg_config_desc *config_desc)
+{
+	if (!config_desc->event_ea)
+		return;
+
+	etm_perf_del_symlink_group(config_desc->event_ea, "events");
+	config_desc->event_ea = NULL;
+}
+
+int __init etm_perf_init(void)
 {
 	int ret;
 
@@ -606,4 +877,8 @@ static int __init etm_perf_init(void)
 
 	return ret;
 }
-device_initcall(etm_perf_init);
+
+void etm_perf_exit(void)
+{
+	perf_pmu_unregister(&etm_pmu);
+}