coresight: removing bind/unbind options from sysfs

The coresight drivers have absolutely no control over bind and unbind
operations triggered from sysfs. The operations simply can't be
cancelled or denied event when one or several tracing sessions are
under way.  Since the memory associated to individual device is
invariably freed, the end result is a kernel crash when the path from
source to sink is travelled again as demonstrated here[1].

One solution could be to keep track of all the path (i.e tracing
session) that get created and iterate through the elements of those path
looking for the coresight device that is being removed.  This proposition
doesn't scale well since there is no upper bound on the amount of
concurrent trace session that can be created.

With the above in mind, this patch prevent devices from being unbounded
from their driver by using the driver->suppress_bind_attr option.  That way
trace sessions can be managed without fearing to loose devices.

Since device can't be removed anymore the xyz_remove() functions found in
each driver is also removed.

[1]. http://www.spinics.net/lists/arm-kernel/msg474952.html

Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

8 files changed, 8 insertions, 91 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 77d0f9c1118d..92969dae739d 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -489,15 +489,6 @@ err_misc_register:
 	return ret;
 }
 
-static int etb_remove(struct amba_device *adev)
-{
-	struct etb_drvdata *drvdata = amba_get_drvdata(adev);
-
-	misc_deregister(&drvdata->miscdev);
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int etb_runtime_suspend(struct device *dev)
 {
@@ -537,10 +528,10 @@ static struct amba_driver etb_driver = {
 		.name	= "coresight-etb10",
 		.owner	= THIS_MODULE,
 		.pm	= &etb_dev_pm_ops,
+		.suppress_bind_attrs = true,
 
 	},
 	.probe		= etb_probe,
-	.remove		= etb_remove,
 	.id_table	= etb_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index d630b7ece735..5981fcc69960 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -1877,17 +1877,6 @@ err_arch_supported:
 	return ret;
 }
 
-static int etm_remove(struct amba_device *adev)
-{
-	struct etm_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	if (--etm_count == 0)
-		unregister_hotcpu_notifier(&etm_cpu_notifier);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int etm_runtime_suspend(struct device *dev)
 {
@@ -1948,9 +1937,9 @@ static struct amba_driver etm_driver = {
 		.name	= "coresight-etm3x",
 		.owner	= THIS_MODULE,
 		.pm	= &etm_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= etm_probe,
-	.remove		= etm_remove,
 	.id_table	= etm_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index a6707642bb23..167004f9c42b 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -2684,17 +2684,6 @@ err_coresight_register:
 	return ret;
 }
 
-static int etm4_remove(struct amba_device *adev)
-{
-	struct etmv4_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	if (--etm4_count == 0)
-		unregister_hotcpu_notifier(&etm4_cpu_notifier);
-
-	return 0;
-}
-
 static struct amba_id etm4_ids[] = {
 	{       /* ETM 4.0 - Qualcomm */
 		.id	= 0x0003b95d,
@@ -2712,9 +2701,9 @@ static struct amba_id etm4_ids[] = {
 static struct amba_driver etm4x_driver = {
 	.drv = {
 		.name   = "coresight-etm4x",
+		.suppress_bind_attrs = true,
 	},
 	.probe		= etm4_probe,
-	.remove		= etm4_remove,
 	.id_table	= etm4_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
index 2e36bde7fcb4..25e8ea140a09 100644
--- a/drivers/hwtracing/coresight/coresight-funnel.c
+++ b/drivers/hwtracing/coresight/coresight-funnel.c
@@ -226,14 +226,6 @@ static int funnel_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int funnel_remove(struct amba_device *adev)
-{
-	struct funnel_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int funnel_runtime_suspend(struct device *dev)
 {
@@ -273,9 +265,9 @@ static struct amba_driver funnel_driver = {
 		.name	= "coresight-funnel",
 		.owner	= THIS_MODULE,
 		.pm	= &funnel_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= funnel_probe,
-	.remove		= funnel_remove,
 	.id_table	= funnel_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-replicator-qcom.c b/drivers/hwtracing/coresight/coresight-replicator-qcom.c
index 584059e9e866..444815179460 100644
--- a/drivers/hwtracing/coresight/coresight-replicator-qcom.c
+++ b/drivers/hwtracing/coresight/coresight-replicator-qcom.c
@@ -156,15 +156,6 @@ static int replicator_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int replicator_remove(struct amba_device *adev)
-{
-	struct replicator_state *drvdata = amba_get_drvdata(adev);
-
-	pm_runtime_disable(&adev->dev);
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int replicator_runtime_suspend(struct device *dev)
 {
@@ -206,9 +197,9 @@ static struct amba_driver replicator_driver = {
 	.drv = {
 		.name	= "coresight-replicator-qcom",
 		.pm	= &replicator_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= replicator_probe,
-	.remove		= replicator_remove,
 	.id_table	= replicator_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index 963ac197c253..b77d700a3f0e 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -127,20 +127,6 @@ out_disable_pm:
 	return ret;
 }
 
-static int replicator_remove(struct platform_device *pdev)
-{
-	struct replicator_drvdata *drvdata = platform_get_drvdata(pdev);
-
-	coresight_unregister(drvdata->csdev);
-	pm_runtime_get_sync(&pdev->dev);
-	if (!IS_ERR(drvdata->atclk))
-		clk_disable_unprepare(drvdata->atclk);
-	pm_runtime_put_noidle(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int replicator_runtime_suspend(struct device *dev)
 {
@@ -175,11 +161,11 @@ static const struct of_device_id replicator_match[] = {
 
 static struct platform_driver replicator_driver = {
 	.probe          = replicator_probe,
-	.remove         = replicator_remove,
 	.driver         = {
 		.name   = "coresight-replicator",
 		.of_match_table = replicator_match,
 		.pm	= &replicator_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index a57c7ec1661f..570d96815f78 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -770,19 +770,6 @@ err_devm_kzalloc:
 	return ret;
 }
 
-static int tmc_remove(struct amba_device *adev)
-{
-	struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
-
-	misc_deregister(&drvdata->miscdev);
-	coresight_unregister(drvdata->csdev);
-	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
-		dma_free_coherent(drvdata->dev, drvdata->size,
-				  &drvdata->paddr, GFP_KERNEL);
-
-	return 0;
-}
-
 static struct amba_id tmc_ids[] = {
 	{
 		.id     = 0x0003b961,
@@ -795,9 +782,9 @@ static struct amba_driver tmc_driver = {
 	.drv = {
 		.name   = "coresight-tmc",
 		.owner  = THIS_MODULE,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= tmc_probe,
-	.remove		= tmc_remove,
 	.id_table	= tmc_ids,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index 7214efd10db5..ca50e73d9df7 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -172,14 +172,6 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int tpiu_remove(struct amba_device *adev)
-{
-	struct tpiu_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int tpiu_runtime_suspend(struct device *dev)
 {
@@ -223,9 +215,9 @@ static struct amba_driver tpiu_driver = {
 		.name	= "coresight-tpiu",
 		.owner	= THIS_MODULE,
 		.pm	= &tpiu_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= tpiu_probe,
-	.remove		= tpiu_remove,
 	.id_table	= tpiu_ids,
 };