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Message-Id: <20241125094816.365472-2-yeoreum.yun@arm.com>
Date: Mon, 25 Nov 2024 09:48:08 +0000
From: Yeoreum Yun <yeoreum.yun@....com>
To: suzuki.poulose@....com,
mike.leach@...aro.org,
james.clark@...aro.org,
alexander.shishkin@...ux.intel.com,
bigeasy@...utronix.de,
clrkwllms@...nel.org,
rostedt@...dmis.org
Cc: coresight@...ts.linaro.org,
linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
linux-rt-devel@...ts.linux.dev,
nd@....com,
Levi Yun <yeoreum.yun@....com>
Subject: [PATCH 1/9] coresight: change coresight_device lock type to raw_spinlock_t
From: Levi Yun <yeoreum.yun@....com>
coresight_device->cscfg_csdev_lock can be held during __schedule()
by perf_event_task_sched_out()/in().
Since coresight->cscfg_csdev_lock type is spinlock_t and
perf_event_task_sched_out()/in() is called after acquiring rq_lock,
which is raw_spinlock_t (an unsleepable lock),
this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.
To address this, change type of coresight_device->cscfg_csdev_lock
from spinlock_t to raw_spinlock_t.
Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>
---
.../hwtracing/coresight/coresight-syscfg.c | 75 +++++++++----------
include/linux/coresight.h | 2 +-
2 files changed, 35 insertions(+), 42 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index 11138a9762b0..b7e9fb822e8f 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -65,7 +65,6 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
{
struct cscfg_config_csdev *config_csdev = NULL;
struct cscfg_feature_csdev *feat_csdev;
- unsigned long flags;
int i;
/* look at each required feature and see if it matches any feature on the device */
@@ -89,9 +88,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
}
/* if matched features, add config to device.*/
if (config_csdev) {
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- list_add(&config_csdev->node, &csdev->config_csdev_list);
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) {
+ list_add(&config_csdev->node, &csdev->config_csdev_list);
+ }
}
return 0;
@@ -177,7 +176,6 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
struct cscfg_csdev_feat_ops *ops)
{
struct cscfg_feature_csdev *feat_csdev;
- unsigned long flags;
int err;
if (!ops->load_feat)
@@ -194,9 +192,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
/* add to internal csdev feature list & initialise using reset call */
cscfg_reset_feat(feat_csdev);
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- list_add(&feat_csdev->node, &csdev->feature_csdev_list);
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) {
+ list_add(&feat_csdev->node, &csdev->feature_csdev_list);
+ }
return 0;
}
@@ -765,7 +763,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev,
INIT_LIST_HEAD(&csdev->feature_csdev_list);
INIT_LIST_HEAD(&csdev->config_csdev_list);
- spin_lock_init(&csdev->cscfg_csdev_lock);
+ raw_spin_lock_init(&csdev->cscfg_csdev_lock);
return 0;
}
@@ -853,17 +851,14 @@ EXPORT_SYMBOL_GPL(cscfg_unregister_csdev);
void cscfg_csdev_reset_feats(struct coresight_device *csdev)
{
struct cscfg_feature_csdev *feat_csdev;
- unsigned long flags;
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
+ guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock);
+
if (list_empty(&csdev->feature_csdev_list))
- goto unlock_exit;
+ return;
list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node)
cscfg_reset_feat(feat_csdev);
-
-unlock_exit:
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
}
EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
@@ -1048,7 +1043,6 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
{
struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item;
const struct cscfg_config_desc *config_desc;
- unsigned long flags;
int err = 0;
/* quickly check global count */
@@ -1059,17 +1053,17 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
* Look for matching configuration - set the active configuration
* context if found.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
- config_desc = config_csdev_item->config_desc;
- if ((atomic_read(&config_desc->active_cnt)) &&
- ((unsigned long)config_desc->event_ea->var == cfg_hash)) {
- config_csdev_active = config_csdev_item;
- csdev->active_cscfg_ctxt = (void *)config_csdev_active;
- break;
+ scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) {
+ list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
+ config_desc = config_csdev_item->config_desc;
+ if ((atomic_read(&config_desc->active_cnt)) &&
+ ((unsigned long)config_desc->event_ea->var == cfg_hash)) {
+ config_csdev_active = config_csdev_item;
+ csdev->active_cscfg_ctxt = (void *)config_csdev_active;
+ break;
+ }
}
}
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
/*
* If found, attempt to enable
@@ -1090,12 +1084,12 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
*
* Set enabled if OK, err if not.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- if (csdev->active_cscfg_ctxt)
- config_csdev_active->enabled = true;
- else
- err = -EBUSY;
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
+ scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) {
+ if (csdev->active_cscfg_ctxt)
+ config_csdev_active->enabled = true;
+ else
+ err = -EBUSY;
+ }
}
}
return err;
@@ -1117,23 +1111,22 @@ EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
{
struct cscfg_config_csdev *config_csdev;
- unsigned long flags;
/*
* Check if we have an active config, and that it was successfully enabled.
* If it was not enabled, we have no work to do, otherwise mark as disabled.
* Clear the active config pointer.
*/
- spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
- config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
- if (config_csdev) {
- if (!config_csdev->enabled)
- config_csdev = NULL;
- else
- config_csdev->enabled = false;
+ scoped_guard(raw_spinlock_irqsave, &csdev->cscfg_csdev_lock) {
+ config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
+ if (config_csdev) {
+ if (!config_csdev->enabled)
+ config_csdev = NULL;
+ else
+ config_csdev->enabled = false;
+ }
+ csdev->active_cscfg_ctxt = NULL;
}
- csdev->active_cscfg_ctxt = NULL;
- spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
/* true if there was an enabled active config */
if (config_csdev)
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index c13342594278..924b58c343b3 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -296,7 +296,7 @@ struct coresight_device {
/* system configuration and feature lists */
struct list_head feature_csdev_list;
struct list_head config_csdev_list;
- spinlock_t cscfg_csdev_lock;
+ raw_spinlock_t cscfg_csdev_lock;
void *active_cscfg_ctxt;
};
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
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