Moving etm_drvdata::enable to an atomic type that gives the
'state' of the tracer, i.e disabled, handled via sysFS or Perf.
That way a tracer can't be used if it is already marshaled by
another subsystem.
Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
drivers/hwtracing/coresight/coresight-etm.h | 11 +++++++++--
drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 4 ++--
drivers/hwtracing/coresight/coresight-etm3x.c | 21 +++++++++++++++------
3 files changed, 26 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 9317510d555f..0996537ff142 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -13,6 +13,7 @@
#ifndef _CORESIGHT_CORESIGHT_ETM_H
#define _CORESIGHT_CORESIGHT_ETM_H
+#include <asm/local.h>
#include <linux/spinlock.h>
#include "coresight-priv.h"
@@ -214,7 +215,7 @@ struct etm_config {
* @port_size: port size as reported by ETMCR bit 4-6 and 21.
* @arch: ETM/PTM version number.
* @use_cpu14: true if management registers need to be accessed via CP14.
- * @enable: is this ETM/PTM currently tracing.
+ * @state: this tracer's state, i.e sysFS, Perf or disabled.
* @sticky_enable: true if ETM base configuration has been done.
* @boot_enable:true if we should start tracing at boot time.
* @os_unlock: true if access to management registers is allowed.
@@ -238,7 +239,7 @@ struct etm_drvdata {
int port_size;
u8 arch;
bool use_cp14;
- bool enable;
+ local_t state;
bool sticky_enable;
bool boot_enable;
bool os_unlock;
@@ -253,6 +254,12 @@ struct etm_drvdata {
struct etm_config *config;
};
+enum etm_state {
+ ETM_STATE_DISABLED,
+ ETM_STATE_SYSFS,
+ ETM_STATE_PERF,
+};
+
enum etm_addr_type {
ETM_ADDR_TYPE_NONE,
ETM_ADDR_TYPE_SINGLE,
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
index 410d29e2b90c..bc8f04214567 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -811,7 +811,7 @@ static ssize_t cntr_val_show(struct device *dev,
if (WARN_ON_ONCE(!config))
return -EINVAL;
- if (!drvdata->enable) {
+ if (!local_read(&drvdata->state)) {
spin_lock(&drvdata->spinlock);
for (i = 0; i < drvdata->nr_cntr; i++)
ret += sprintf(buf, "counter %d: %x\n",
@@ -1072,7 +1072,7 @@ static ssize_t seq_curr_state_show(struct device *dev,
if (WARN_ON_ONCE(!config))
return -EINVAL;
- if (!drvdata->enable) {
+ if (!local_read(&drvdata->state)) {
val = config->seq_curr_state;
goto out;
}
diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index 3d7fa0b2acf9..3fe6433764d4 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -320,7 +320,7 @@ int etm_get_trace_id(struct etm_drvdata *drvdata)
if (!drvdata)
goto out;
- if (!drvdata->enable)
+ if (!local_read(&drvdata->state))
return drvdata->traceid;
pm_runtime_get_sync(drvdata->dev);
@@ -354,6 +354,12 @@ static int sysfs_etm_enable(struct coresight_device *csdev)
pm_runtime_get_sync(csdev->dev.parent);
spin_lock(&drvdata->spinlock);
+ if (local_cmpxchg(&drvdata->state,
+ ETM_STATE_DISABLED, ETM_STATE_SYSFS)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
/*
* Configure the ETM only if the CPU is online. If it isn't online
* hw configuration will take place when 'CPU_STARTING' is received
@@ -366,17 +372,20 @@ static int sysfs_etm_enable(struct coresight_device *csdev)
goto err;
}
- drvdata->enable = true;
drvdata->sticky_enable = true;
spin_unlock(&drvdata->spinlock);
dev_info(drvdata->dev, "ETM tracing enabled\n");
return 0;
-err:
+out:
spin_unlock(&drvdata->spinlock);
pm_runtime_put(csdev->dev.parent);
return ret;
+
+err:
+ local_set(&drvdata->state, ETM_STATE_DISABLED);
+ goto out;
}
static void etm_disable_hw(void *info)
@@ -425,7 +434,7 @@ static void sysfs_etm_disable(struct coresight_device *csdev)
* ensures that register writes occur when cpu is powered.
*/
smp_call_function_single(drvdata->cpu, etm_disable_hw, drvdata, 1);
- drvdata->enable = false;
+ local_set(&drvdata->state, ETM_STATE_DISABLED);
spin_unlock(&drvdata->spinlock);
put_online_cpus();
@@ -460,7 +469,7 @@ static int etm_cpu_callback(struct notifier_block *nfb, unsigned long action,
etmdrvdata[cpu]->os_unlock = true;
}
- if (etmdrvdata[cpu]->enable)
+ if (local_read(&etmdrvdata[cpu]->state))
etm_enable_hw(etmdrvdata[cpu]);
spin_unlock(&etmdrvdata[cpu]->spinlock);
break;
@@ -473,7 +482,7 @@ static int etm_cpu_callback(struct notifier_block *nfb, unsigned long action,
case CPU_DYING:
spin_lock(&etmdrvdata[cpu]->spinlock);
- if (etmdrvdata[cpu]->enable)
+ if (local_read(&etmdrvdata[cpu]->state))
etm_disable_hw(etmdrvdata[cpu]);
spin_unlock(&etmdrvdata[cpu]->spinlock);
break;
--
1.9.1
--
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