linux-kernel - [PATCH 2/7] coresight: perf: Add "sinks" group to PMU directory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190115230742.13730-3-mathieu.poirier@linaro.org>
Date:   Tue, 15 Jan 2019 16:07:37 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     acme@...nel.org, peterz@...radead.org, gregkh@...uxfoundation.org
Cc:     mingo@...hat.com, tglx@...utronix.de,
        alexander.shishkin@...ux.intel.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, will.deacon@....com,
        mark.rutland@....com, jolsa@...hat.com, namhyung@...nel.org,
        adrian.hunter@...el.com, ast@...nel.org, hpa@...or.com,
        suzuki.poulose@....com, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 2/7] coresight: perf: Add "sinks" group to PMU directory

Add a "sinks" directory entry so that users can see all the sinks
available in the system in a single place.  Individual sink are added
as they are registered with the coresight bus.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 .../hwtracing/coresight/coresight-etm-perf.c  | 43 +++++++++++++++++++
 .../hwtracing/coresight/coresight-etm-perf.h  |  1 +
 drivers/hwtracing/coresight/coresight.c       | 17 ++++++++
 3 files changed, 61 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index f21eb28b6782..292bd409a68c 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -14,6 +14,7 @@
 #include <linux/perf_event.h>
 #include <linux/percpu-defs.h>
 #include <linux/slab.h>
+#include <linux/stringhash.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
@@ -43,8 +44,18 @@ static const struct attribute_group etm_pmu_format_group = {
 	.attrs  = etm_config_formats_attr,
 };
 
+static struct attribute *etm_config_sinks_attr[] = {
+	NULL,
+};
+
+static const struct attribute_group etm_pmu_sinks_group = {
+	.name   = "sinks",
+	.attrs  = etm_config_sinks_attr,
+};
+
 static const struct attribute_group *etm_pmu_attr_groups[] = {
 	&etm_pmu_format_group,
+	&etm_pmu_sinks_group,
 	NULL,
 };
 
@@ -479,6 +490,38 @@ int etm_perf_symlink(struct coresight_device *csdev, bool link)
 	return 0;
 }
 
+static ssize_t etm_perf_sink_name_show(struct device *dev,
+				       struct device_attribute *dattr,
+				       char *buf)
+{
+	/* See function coresight_sink_by_id() to know where this is used */
+	u32 hash = hashlen_hash(hashlen_string(NULL, dattr->attr.name));
+
+	return scnprintf(buf, PAGE_SIZE, "%x\n", hash);
+}
+
+int etm_perf_symlink_sink(struct coresight_device *csdev)
+{
+	struct device *pmu_dev = etm_pmu.dev;
+	struct device *pdev = csdev->dev.parent;
+	struct device_attribute *dev_attr;
+
+	if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
+	    csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
+		return -EINVAL;
+
+	if (!etm_perf_up)
+		return -EPROBE_DEFER;
+
+	dev_attr = kzalloc(sizeof(*dev_attr), GFP_KERNEL);
+	dev_attr->attr.name = kstrdup(dev_name(pdev), GFP_KERNEL);
+	dev_attr->attr.mode = 0444;
+	dev_attr->show = etm_perf_sink_name_show;
+
+	return sysfs_add_file_to_group(&pmu_dev->kobj,
+				       &dev_attr->attr, "sinks");
+}
+
 static int __init etm_perf_init(void)
 {
 	int ret;
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.h b/drivers/hwtracing/coresight/coresight-etm-perf.h
index da7d9336a15c..529a47285c0f 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.h
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.h
@@ -59,6 +59,7 @@ struct etm_event_data {
 
 #ifdef CONFIG_CORESIGHT
 int etm_perf_symlink(struct coresight_device *csdev, bool link);
+int etm_perf_symlink_sink(struct coresight_device *csdev);
 static inline void *etm_perf_sink_config(struct perf_output_handle *handle)
 {
 	struct etm_event_data *data = perf_get_aux(handle);
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 2b0df1a0a8df..526f122a38ee 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/pm_runtime.h>
 
+#include "coresight-etm-perf.h"
 #include "coresight-priv.h"
 
 static DEFINE_MUTEX(coresight_mutex);
@@ -1167,6 +1168,22 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 		goto err_out;
 	}
 
+	if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
+	    csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
+		ret = etm_perf_symlink_sink(csdev);
+
+		if (ret) {
+			device_unregister(&csdev->dev);
+			/*
+			 * As with the above, all resources are free'd
+			 * explicitly via coresight_device_release() triggered
+			 * from put_device(), which is in turn called from
+			 * function device_unregister().
+			 */
+			goto err_out;
+		}
+	}
+
 	mutex_lock(&coresight_mutex);
 
 	coresight_fixup_device_conns(csdev);
-- 
2.17.1