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* [PATCH v6 10/13] coresight: etm3x: change drvdata->spinlock type to raw_spin_lock_t
From: Yeoreum Yun @ 2026-04-22 13:22 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

etm_starting_cpu()/etm_dying_cpu() are called in not sleepable context.
This poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.

To address this, change etm3's drvdata->spinlock type to raw_spin_lock_t.
This will be good to align with etm4x.

Reviewed-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm.h   |   2 +-
 .../coresight/coresight-etm3x-core.c          |  18 +--
 .../coresight/coresight-etm3x-sysfs.c         | 130 +++++++++---------
 3 files changed, 75 insertions(+), 75 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 1d753cca2943..40f20daded4f 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -232,7 +232,7 @@ struct etm_drvdata {
 	struct csdev_access		csa;
 	struct clk			*atclk;
 	struct coresight_device		*csdev;
-	spinlock_t			spinlock;
+	raw_spinlock_t			spinlock;
 	int				cpu;
 	int				port_size;
 	u8				arch;
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index a547a6d2e0bd..4a702b515733 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -511,7 +511,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_pat
 	struct etm_enable_arg arg = { };
 	int ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	drvdata->traceid = path->trace_id;
 
@@ -534,7 +534,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_pat
 	if (ret)
 		etm_release_trace_id(drvdata);
 
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	if (!ret)
 		dev_dbg(&csdev->dev, "ETM tracing enabled\n");
@@ -634,7 +634,7 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
 	 * DYING hotplug callback is serviced by the ETM driver.
 	 */
 	cpus_read_lock();
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 
 	/*
 	 * Executing etm_disable_hw on the cpu whose ETM is being disabled
@@ -643,7 +643,7 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
 	smp_call_function_single(drvdata->cpu, etm_disable_sysfs_smp_call,
 				 drvdata, 1);
 
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	cpus_read_unlock();
 
 	/*
@@ -709,7 +709,7 @@ static int etm_starting_cpu(unsigned int cpu)
 	if (!etmdrvdata[cpu])
 		return 0;
 
-	spin_lock(&etmdrvdata[cpu]->spinlock);
+	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
 	if (!etmdrvdata[cpu]->os_unlock) {
 		etm_os_unlock(etmdrvdata[cpu]);
 		etmdrvdata[cpu]->os_unlock = true;
@@ -717,7 +717,7 @@ static int etm_starting_cpu(unsigned int cpu)
 
 	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
 		etm_enable_hw(etmdrvdata[cpu]);
-	spin_unlock(&etmdrvdata[cpu]->spinlock);
+	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
 	return 0;
 }
 
@@ -726,10 +726,10 @@ static int etm_dying_cpu(unsigned int cpu)
 	if (!etmdrvdata[cpu])
 		return 0;
 
-	spin_lock(&etmdrvdata[cpu]->spinlock);
+	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
 	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
 		etm_disable_hw(etmdrvdata[cpu]);
-	spin_unlock(&etmdrvdata[cpu]->spinlock);
+	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
 	return 0;
 }
 
@@ -856,7 +856,7 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
 
 	desc.access = drvdata->csa = CSDEV_ACCESS_IOMEM(base);
 
-	spin_lock_init(&drvdata->spinlock);
+	raw_spin_lock_init(&drvdata->spinlock);
 
 	drvdata->atclk = devm_clk_get_optional_enabled(dev, "atclk");
 	if (IS_ERR(drvdata->atclk))
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
index 762109307b86..42b12c33516b 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -49,13 +49,13 @@ static ssize_t etmsr_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
 	pm_runtime_get_sync(dev->parent);
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 	CS_UNLOCK(drvdata->csa.base);
 
 	val = etm_readl(drvdata, ETMSR);
 
 	CS_LOCK(drvdata->csa.base);
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 	pm_runtime_put(dev->parent);
 
 	return sprintf(buf, "%#lx\n", val);
@@ -76,7 +76,7 @@ static ssize_t reset_store(struct device *dev,
 		return ret;
 
 	if (val) {
-		spin_lock(&drvdata->spinlock);
+		raw_spin_lock(&drvdata->spinlock);
 		memset(config, 0, sizeof(struct etm_config));
 		config->mode = ETM_MODE_EXCLUDE;
 		config->trigger_event = ETM_DEFAULT_EVENT_VAL;
@@ -86,7 +86,7 @@ static ssize_t reset_store(struct device *dev,
 
 		etm_set_default(config);
 		etm_release_trace_id(drvdata);
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 	}
 
 	return size;
@@ -117,7 +117,7 @@ static ssize_t mode_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->mode = val & ETM_MODE_ALL;
 
 	if (config->mode & ETM_MODE_EXCLUDE)
@@ -168,12 +168,12 @@ static ssize_t mode_store(struct device *dev,
 	if (config->mode & (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER))
 		etm_config_trace_mode(config);
 
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 
 err_unlock:
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 	return ret;
 }
 static DEVICE_ATTR_RW(mode);
@@ -299,9 +299,9 @@ static ssize_t addr_idx_store(struct device *dev,
 	 * Use spinlock to ensure index doesn't change while it gets
 	 * dereferenced multiple times within a spinlock block elsewhere.
 	 */
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->addr_idx = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -315,16 +315,16 @@ static ssize_t addr_single_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_SINGLE)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EINVAL;
 	}
 
 	val = config->addr_val[idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -343,17 +343,17 @@ static ssize_t addr_single_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_SINGLE)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EINVAL;
 	}
 
 	config->addr_val[idx] = val;
 	config->addr_type[idx] = ETM_ADDR_TYPE_SINGLE;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -367,23 +367,23 @@ static ssize_t addr_range_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (idx % 2 != 0) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 	if (!((config->addr_type[idx] == ETM_ADDR_TYPE_NONE &&
 	       config->addr_type[idx + 1] == ETM_ADDR_TYPE_NONE) ||
 	      (config->addr_type[idx] == ETM_ADDR_TYPE_RANGE &&
 	       config->addr_type[idx + 1] == ETM_ADDR_TYPE_RANGE))) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
 	val1 = config->addr_val[idx];
 	val2 = config->addr_val[idx + 1];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx %#lx\n", val1, val2);
 }
@@ -403,17 +403,17 @@ static ssize_t addr_range_store(struct device *dev,
 	if (val1 > val2)
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (idx % 2 != 0) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 	if (!((config->addr_type[idx] == ETM_ADDR_TYPE_NONE &&
 	       config->addr_type[idx + 1] == ETM_ADDR_TYPE_NONE) ||
 	      (config->addr_type[idx] == ETM_ADDR_TYPE_RANGE &&
 	       config->addr_type[idx + 1] == ETM_ADDR_TYPE_RANGE))) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
@@ -422,7 +422,7 @@ static ssize_t addr_range_store(struct device *dev,
 	config->addr_val[idx + 1] = val2;
 	config->addr_type[idx + 1] = ETM_ADDR_TYPE_RANGE;
 	config->enable_ctrl1 |= (1 << (idx/2));
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -436,16 +436,16 @@ static ssize_t addr_start_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_START)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
 	val = config->addr_val[idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -464,11 +464,11 @@ static ssize_t addr_start_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_START)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
@@ -476,7 +476,7 @@ static ssize_t addr_start_store(struct device *dev,
 	config->addr_type[idx] = ETM_ADDR_TYPE_START;
 	config->startstop_ctrl |= (1 << idx);
 	config->enable_ctrl1 |= ETMTECR1_START_STOP;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -490,16 +490,16 @@ static ssize_t addr_stop_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_STOP)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
 	val = config->addr_val[idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -518,11 +518,11 @@ static ssize_t addr_stop_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
 	if (!(config->addr_type[idx] == ETM_ADDR_TYPE_NONE ||
 	      config->addr_type[idx] == ETM_ADDR_TYPE_STOP)) {
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return -EPERM;
 	}
 
@@ -530,7 +530,7 @@ static ssize_t addr_stop_store(struct device *dev,
 	config->addr_type[idx] = ETM_ADDR_TYPE_STOP;
 	config->startstop_ctrl |= (1 << (idx + 16));
 	config->enable_ctrl1 |= ETMTECR1_START_STOP;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -543,9 +543,9 @@ static ssize_t addr_acctype_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = config->addr_acctype[config->addr_idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -563,9 +563,9 @@ static ssize_t addr_acctype_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->addr_acctype[config->addr_idx] = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -601,9 +601,9 @@ static ssize_t cntr_idx_store(struct device *dev,
 	 * Use spinlock to ensure index doesn't change while it gets
 	 * dereferenced multiple times within a spinlock block elsewhere.
 	 */
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->cntr_idx = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -616,9 +616,9 @@ static ssize_t cntr_rld_val_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = config->cntr_rld_val[config->cntr_idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -636,9 +636,9 @@ static ssize_t cntr_rld_val_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->cntr_rld_val[config->cntr_idx] = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -651,9 +651,9 @@ static ssize_t cntr_event_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = config->cntr_event[config->cntr_idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -671,9 +671,9 @@ static ssize_t cntr_event_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->cntr_event[config->cntr_idx] = val & ETM_EVENT_MASK;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -686,9 +686,9 @@ static ssize_t cntr_rld_event_show(struct device *dev,
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etm_config *config = &drvdata->config;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = config->cntr_rld_event[config->cntr_idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -706,9 +706,9 @@ static ssize_t cntr_rld_event_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->cntr_rld_event[config->cntr_idx] = val & ETM_EVENT_MASK;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -723,11 +723,11 @@ static ssize_t cntr_val_show(struct device *dev,
 	struct etm_config *config = &drvdata->config;
 
 	if (!coresight_get_mode(drvdata->csdev)) {
-		spin_lock(&drvdata->spinlock);
+		raw_spin_lock(&drvdata->spinlock);
 		for (i = 0; i < drvdata->nr_cntr; i++)
 			ret += sprintf(buf, "counter %d: %x\n",
 				       i, config->cntr_val[i]);
-		spin_unlock(&drvdata->spinlock);
+		raw_spin_unlock(&drvdata->spinlock);
 		return ret;
 	}
 
@@ -752,9 +752,9 @@ static ssize_t cntr_val_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->cntr_val[config->cntr_idx] = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -947,13 +947,13 @@ static ssize_t seq_curr_state_show(struct device *dev,
 	}
 
 	pm_runtime_get_sync(dev->parent);
-	spin_lock_irqsave(&drvdata->spinlock, flags);
+	raw_spin_lock_irqsave(&drvdata->spinlock, flags);
 
 	CS_UNLOCK(drvdata->csa.base);
 	val = (etm_readl(drvdata, ETMSQR) & ETM_SQR_MASK);
 	CS_LOCK(drvdata->csa.base);
 
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
 	pm_runtime_put(dev->parent);
 out:
 	return sprintf(buf, "%#lx\n", val);
@@ -1012,9 +1012,9 @@ static ssize_t ctxid_idx_store(struct device *dev,
 	 * Use spinlock to ensure index doesn't change while it gets
 	 * dereferenced multiple times within a spinlock block elsewhere.
 	 */
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->ctxid_idx = val;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
@@ -1034,9 +1034,9 @@ static ssize_t ctxid_pid_show(struct device *dev,
 	if (task_active_pid_ns(current) != &init_pid_ns)
 		return -EINVAL;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	val = config->ctxid_pid[config->ctxid_idx];
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return sprintf(buf, "%#lx\n", val);
 }
@@ -1066,9 +1066,9 @@ static ssize_t ctxid_pid_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	spin_lock(&drvdata->spinlock);
+	raw_spin_lock(&drvdata->spinlock);
 	config->ctxid_pid[config->ctxid_idx] = pid;
-	spin_unlock(&drvdata->spinlock);
+	raw_spin_unlock(&drvdata->spinlock);
 
 	return size;
 }
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 07/13] coresight: etm4x: fix inconsistencies with sysfs configuration
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

The current ETM4x configuration via sysfs can lead to
several inconsistencies:

  - If the configuration is modified via sysfs while a perf session is
    active, the running configuration may differ before a sched-out and
    after a subsequent sched-in.

  - If a perf session and a sysfs session enable tracing concurrently,
    the configuration from configfs may become corrupted.

  - There is a risk of corrupting drvdata->config if a perf session enables
    tracing while cscfg_csdev_disable_active_config() is being handled in
    etm4_disable_sysfs().

To resolve these issues, separate the configuration into:

  - active_config: the configuration applied to the current session
  - config: the configuration set via sysfs

Additionally:

  - Apply the configuration from configfs after taking the appropriate mode.

  - Since active_config and related fields are accessed only by the local CPU
    in etm4_enable/disable_sysfs_smp_call() (similar to perf enable/disable),
    remove the lock/unlock from the sysfs enable/disable path and
    startup/dying_cpu except when to access config fields.

Fixes: 54ff892b76c6 ("coresight: etm4x: splitting struct etmv4_drvdata")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 .../hwtracing/coresight/coresight-etm4x-cfg.c |   2 +-
 .../coresight/coresight-etm4x-core.c          | 106 ++++++++++--------
 drivers/hwtracing/coresight/coresight-etm4x.h |   2 +
 3 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
index d14d7c8a23e5..0553771d04e7 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
@@ -47,7 +47,7 @@ static int etm4_cfg_map_reg_offset(struct etmv4_drvdata *drvdata,
 				   struct cscfg_regval_csdev *reg_csdev, u32 offset)
 {
 	int err = -EINVAL, idx;
-	struct etmv4_config *drvcfg = &drvdata->config;
+	struct etmv4_config *drvcfg = &drvdata->active_config;
 	u32 off_mask;
 
 	if (((offset >= TRCEVENTCTL0R) && (offset <= TRCVIPCSSCTLR)) ||
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index bbfcd7e16532..5c74e3d63dcd 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -245,6 +245,10 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
 
 struct etm4_enable_arg {
 	struct etmv4_drvdata *drvdata;
+	const struct coresight_path *path;
+	unsigned long cfg_hash;
+	int preset;
+	struct etmv4_config config;
 	int rc;
 };
 
@@ -270,10 +274,11 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata)
 static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata)
 {
 	u64 trfcr = drvdata->trfcr;
+	struct etmv4_config *config = &drvdata->active_config;
 
-	if (drvdata->config.mode & ETM_MODE_EXCL_KERN)
+	if (config->mode & ETM_MODE_EXCL_KERN)
 		trfcr &= ~TRFCR_EL1_ExTRE;
-	if (drvdata->config.mode & ETM_MODE_EXCL_USER)
+	if (config->mode & ETM_MODE_EXCL_USER)
 		trfcr &= ~TRFCR_EL1_E0TRE;
 
 	return trfcr;
@@ -281,7 +286,7 @@ static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata)
 
 /*
  * etm4x_allow_trace - Allow CPU tracing in the respective ELs,
- * as configured by the drvdata->config.mode for the current
+ * as configured by the drvdata->active_config.mode for the current
  * session. Even though we have TRCVICTLR bits to filter the
  * trace in the ELs, it doesn't prevent the ETM from generating
  * a packet (e.g, TraceInfo) that might contain the addresses from
@@ -292,12 +297,13 @@ static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata)
 static void etm4x_allow_trace(struct etmv4_drvdata *drvdata)
 {
 	u64 trfcr, guest_trfcr;
+	struct etmv4_config *config = &drvdata->active_config;
 
 	/* If the CPU doesn't support FEAT_TRF, nothing to do */
 	if (!drvdata->trfcr)
 		return;
 
-	if (drvdata->config.mode & ETM_MODE_EXCL_HOST)
+	if (config->mode & ETM_MODE_EXCL_HOST)
 		trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);
 	else
 		trfcr = etm4x_get_kern_user_filter(drvdata);
@@ -305,7 +311,7 @@ static void etm4x_allow_trace(struct etmv4_drvdata *drvdata)
 	write_trfcr(trfcr);
 
 	/* Set filters for guests and pass to KVM */
-	if (drvdata->config.mode & ETM_MODE_EXCL_GUEST)
+	if (config->mode & ETM_MODE_EXCL_GUEST)
 		guest_trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);
 	else
 		guest_trfcr = etm4x_get_kern_user_filter(drvdata);
@@ -499,7 +505,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 {
 	int i, rc;
 	const struct etmv4_caps *caps = &drvdata->caps;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 	struct coresight_device *csdev = drvdata->csdev;
 	struct device *etm_dev = &csdev->dev;
 	struct csdev_access *csa = &csdev->access;
@@ -618,23 +624,47 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 static void etm4_enable_sysfs_smp_call(void *info)
 {
 	struct etm4_enable_arg *arg = info;
+	struct etmv4_drvdata *drvdata;
 	struct coresight_device *csdev;
 
 	if (WARN_ON(!arg))
 		return;
 
-	csdev = arg->drvdata->csdev;
+	drvdata = arg->drvdata;
+	csdev = drvdata->csdev;
 	if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) {
 		/* Someone is already using the tracer */
 		arg->rc = -EBUSY;
 		return;
 	}
 
-	arg->rc = etm4_enable_hw(arg->drvdata);
+	drvdata->active_config = arg->config;
+
+	if (arg->cfg_hash) {
+		arg->rc = cscfg_csdev_enable_active_config(csdev,
+							   arg->cfg_hash,
+							   arg->preset);
+		if (arg->rc)
+			goto err;
+	}
+
+	drvdata->trcid = arg->path->trace_id;
 
+	/* Tracer will never be paused in sysfs mode */
+	drvdata->paused = false;
+
+	arg->rc = etm4_enable_hw(drvdata);
+	if (arg->rc) {
+		cscfg_csdev_disable_active_config(csdev);
+		goto err;
+	}
+
+	drvdata->sticky_enable = true;
+
+	return;
+err:
 	/* The tracer didn't start */
-	if (arg->rc)
-		coresight_set_mode(csdev, CS_MODE_DISABLED);
+	coresight_set_mode(csdev, CS_MODE_DISABLED);
 }
 
 /*
@@ -672,7 +702,7 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata,
 	int ctridx;
 	int rselector;
 	const struct etmv4_caps *caps = &drvdata->caps;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 
 	/* No point in trying if we don't have at least one counter */
 	if (!caps->nr_cntr)
@@ -756,7 +786,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 	int ret = 0;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	const struct etmv4_caps *caps = &drvdata->caps;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 	struct perf_event_attr max_timestamp = {
 		.ATTR_CFG_FLD_timestamp_CFG = U64_MAX,
 	};
@@ -918,40 +948,29 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa
 
 	/* enable any config activated by configfs */
 	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
-	if (cfg_hash) {
-		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
-		if (ret) {
-			etm4_release_trace_id(drvdata);
-			return ret;
-		}
-	}
-
-	raw_spin_lock(&drvdata->spinlock);
-
-	drvdata->trcid = path->trace_id;
-
-	/* Tracer will never be paused in sysfs mode */
-	drvdata->paused = false;
 
 	/*
 	 * Executing etm4_enable_hw on the cpu whose ETM is being enabled
 	 * ensures that register writes occur when cpu is powered.
 	 */
 	arg.drvdata = drvdata;
+	arg.path = path;
+	arg.cfg_hash = cfg_hash;
+	arg.preset = preset;
+
+	raw_spin_lock(&drvdata->spinlock);
+	arg.config = drvdata->config;
+	raw_spin_unlock(&drvdata->spinlock);
+
 	ret = smp_call_function_single(drvdata->cpu,
 				       etm4_enable_sysfs_smp_call, &arg, 1);
 	if (!ret)
 		ret = arg.rc;
 	if (!ret)
-		drvdata->sticky_enable = true;
-
-	if (ret)
+		dev_dbg(&csdev->dev, "ETM tracing enabled\n");
+	else
 		etm4_release_trace_id(drvdata);
 
-	raw_spin_unlock(&drvdata->spinlock);
-
-	if (!ret)
-		dev_dbg(&csdev->dev, "ETM tracing enabled\n");
 	return ret;
 }
 
@@ -1038,7 +1057,7 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
 {
 	u32 control;
 	const struct etmv4_caps *caps = &drvdata->caps;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
 	int i;
@@ -1080,6 +1099,8 @@ static void etm4_disable_sysfs_smp_call(void *info)
 
 	etm4_disable_hw(drvdata);
 
+	cscfg_csdev_disable_active_config(drvdata->csdev);
+
 	coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
 }
 
@@ -1130,7 +1151,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
 	 * DYING hotplug callback is serviced by the ETM driver.
 	 */
 	cpus_read_lock();
-	raw_spin_lock(&drvdata->spinlock);
 
 	/*
 	 * Executing etm4_disable_hw on the cpu whose ETM is being disabled
@@ -1139,10 +1159,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
 	smp_call_function_single(drvdata->cpu, etm4_disable_sysfs_smp_call,
 				 drvdata, 1);
 
-	raw_spin_unlock(&drvdata->spinlock);
-
-	cscfg_csdev_disable_active_config(csdev);
-
 	cpus_read_unlock();
 
 	/*
@@ -1385,6 +1401,7 @@ static void etm4_init_arch_data(void *info)
 	struct etm4_init_arg *init_arg = info;
 	struct etmv4_drvdata *drvdata;
 	struct etmv4_caps *caps;
+	struct etmv4_config *config;
 	struct csdev_access *csa;
 	struct device *dev = init_arg->dev;
 	int i;
@@ -1392,6 +1409,7 @@ static void etm4_init_arch_data(void *info)
 	drvdata = dev_get_drvdata(init_arg->dev);
 	caps = &drvdata->caps;
 	csa = init_arg->csa;
+	config = &drvdata->config;
 
 	/*
 	 * If we are unable to detect the access mechanism,
@@ -1452,7 +1470,7 @@ static void etm4_init_arch_data(void *info)
 
 	/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */
 	caps->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3);
-	drvdata->config.s_ex_level = caps->s_ex_level;
+	config->s_ex_level = caps->s_ex_level;
 	/* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */
 	caps->ns_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_NS_MASK, etmidr3);
 	/*
@@ -1698,7 +1716,7 @@ static void etm4_set_default(struct etmv4_config *config)
 static int etm4_get_next_comparator(struct etmv4_drvdata *drvdata, u32 type)
 {
 	int nr_comparator, index = 0;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 
 	/*
 	 * nr_addr_cmp holds the number of comparator _pair_, so time 2
@@ -1739,7 +1757,7 @@ static int etm4_set_event_filters(struct etmv4_drvdata *drvdata,
 {
 	int i, comparator, ret = 0;
 	u64 address;
-	struct etmv4_config *config = &drvdata->config;
+	struct etmv4_config *config = &drvdata->active_config;
 	struct etm_filters *filters = event->hw.addr_filters;
 
 	if (!filters)
@@ -1857,13 +1875,11 @@ static int etm4_starting_cpu(unsigned int cpu)
 	if (!etmdrvdata[cpu])
 		return 0;
 
-	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
 	if (!etmdrvdata[cpu]->os_unlock)
 		etm4_os_unlock(etmdrvdata[cpu]);
 
 	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
 		etm4_enable_hw(etmdrvdata[cpu]);
-	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
 	return 0;
 }
 
@@ -1872,10 +1888,8 @@ static int etm4_dying_cpu(unsigned int cpu)
 	if (!etmdrvdata[cpu])
 		return 0;
 
-	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
 	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
 		etm4_disable_hw(etmdrvdata[cpu]);
-	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
 	return 0;
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index bfd5e544f68d..a64f948e0d6f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -1067,6 +1067,7 @@ struct etmv4_save_state {
  *		allows tracing at all ELs. We don't want to compute this
  *		at runtime, due to the additional setting of TRFCR_CX when
  *		in EL2. Otherwise, 0.
+ * @active_config:	structure holding current applied configuration parameters.
  * @config:	structure holding configuration parameters.
  * @save_state:	State to be preserved across power loss
  * @paused:	Indicates if the trace unit is paused.
@@ -1088,6 +1089,7 @@ struct etmv4_drvdata {
 	bool				os_unlock : 1;
 	bool				paused : 1;
 	u64				trfcr;
+	struct etmv4_config		active_config;
 	struct etmv4_config		config;
 	struct etmv4_save_state		*save_state;
 	u32				ss_status[ETM_MAX_SS_CMP];
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 09/13] coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf enable
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

In the perf enable path, there are missing cases where
cscfg_csdev_disable_active_config() is not called:

  - Branch broadcast is selected but not supported by the hardware
  - etm4_enable_hw() fails

This can lead to a leak of config_desc->active_cnt.
Fix this by properly calling cscfg_csdev_disable_active_config()
in these error paths.

Fixes: 810ac401db1f ("coresight: etm4x: Add complex configuration handlers to etmv4")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 .../hwtracing/coresight/coresight-etm4x-core.c  | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 66d09e0a4171..d6fd6125ef60 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -895,6 +895,8 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 			 * Missing BB support could cause silent decode errors
 			 * so fail to open if it's not supported.
 			 */
+			if (cfg_hash)
+				cscfg_csdev_disable_active_config(csdev);
 			ret = -EINVAL;
 			goto out;
 		} else {
@@ -911,6 +913,7 @@ static int etm4_enable_perf(struct coresight_device *csdev,
 			    struct coresight_path *path)
 {
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct perf_event_attr *attr = &event->attr;
 	int ret;
 
 	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
@@ -922,7 +925,7 @@ static int etm4_enable_perf(struct coresight_device *csdev,
 	/* Configure the tracer based on the session's specifics */
 	ret = etm4_parse_event_config(csdev, event);
 	if (ret)
-		goto out;
+		goto err;
 
 	drvdata->trcid = path->trace_id;
 
@@ -931,11 +934,17 @@ static int etm4_enable_perf(struct coresight_device *csdev,
 
 	/* And enable it */
 	ret = etm4_enable_hw(drvdata);
+	if (ret) {
+		if (ATTR_CFG_GET_FLD(attr, configid))
+			cscfg_csdev_disable_active_config(csdev);
+		goto err;
+	}
 
-out:
+	return 0;
+
+err:
 	/* Failed to start tracer; roll back to DISABLED mode */
-	if (ret)
-		coresight_set_mode(csdev, CS_MODE_DISABLED);
+	coresight_set_mode(csdev, CS_MODE_DISABLED);
 	return ret;
 }
 
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 08/13] coresight: etm4x: remove redundant call etm4_enable_hw() with hotplug
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

The cpu_online_mask is set at the CPUHP_BRINGUP_CPU step.
In other words, if etm4_enable_sysfs() is called between
CPUHP_BRINGUP_CPU and CPUHP_AP_ARM_CORESIGHT_STARTING,
etm4_enable_hw() may be invoked in etm4_enable_sysfs_smp_call()
and then executed again in etm4_starting_cpu().

To remove this redundant call, take the hotplug lock before executing
etm4_enable_sysfs_smp_call().

Reviewed-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 5c74e3d63dcd..66d09e0a4171 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -962,8 +962,20 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa
 	arg.config = drvdata->config;
 	raw_spin_unlock(&drvdata->spinlock);
 
+	/*
+	 * Take the hotplug lock to prevent redundant calls to etm4_enable_hw().
+	 *
+	 * The cpu_online_mask is set at the CPUHP_BRINGUP_CPU step.
+	 * In other words, if etm4_enable_sysfs() is called between
+	 * CPUHP_BRINGUP_CPU and CPUHP_AP_ARM_CORESIGHT_STARTING,
+	 * etm4_enable_hw() may be invoked in etm4_enable_sysfs_smp_call()
+	 * and then executed again in etm4_starting_cpu().
+	 */
+	cpus_read_lock();
 	ret = smp_call_function_single(drvdata->cpu,
 				       etm4_enable_sysfs_smp_call, &arg, 1);
+	cpus_read_unlock();
+
 	if (!ret)
 		ret = arg.rc;
 	if (!ret)
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 06/13] coresight: etm4x: fix leaked trace id
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

If etm4_enable_sysfs() fails in cscfg_csdev_enable_active_config(),
the trace ID may be leaked because it is not released.

To address this, call etm4_release_trace_id() when etm4_enable_sysfs()
fails in cscfg_csdev_enable_active_config().

Fixes: 7ebd0ec6cf94 ("coresight: configfs: Allow configfs to activate configuration")
Reviewed-by: Jie Gan <jie.gan@oss.qualcomm.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index afa64a339b6e..bbfcd7e16532 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -920,8 +920,10 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa
 	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
 	if (cfg_hash) {
 		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
-		if (ret)
+		if (ret) {
+			etm4_release_trace_id(drvdata);
 			return ret;
+		}
 	}
 
 	raw_spin_lock(&drvdata->spinlock);
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 03/13] coresight: etm4x: introduce struct etm4_caps
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

Introduce struct etm4_caps to describe ETMv4 capabilities
and move capabilities information into it.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 .../coresight/coresight-etm4x-core.c          | 234 +++++++++---------
 .../coresight/coresight-etm4x-sysfs.c         | 192 ++++++++------
 drivers/hwtracing/coresight/coresight-etm4x.h | 176 ++++++-------
 3 files changed, 329 insertions(+), 273 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index ba5b8b423bd4..b2b092a76eb5 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -88,8 +88,9 @@ static int etm4_probe_cpu(unsigned int cpu);
  */
 static bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
 {
-	return (n < drvdata->nr_ss_cmp) &&
-	       drvdata->nr_pe_cmp &&
+	const struct etmv4_caps *caps = &drvdata->caps;
+
+	return (n < caps->nr_ss_cmp) && caps->nr_pe_cmp &&
 	       (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
 }
 
@@ -160,17 +161,20 @@ static void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
 static void etm_detect_os_lock(struct etmv4_drvdata *drvdata,
 			       struct csdev_access *csa)
 {
+	struct etmv4_caps *caps = &drvdata->caps;
 	u32 oslsr = etm4x_relaxed_read32(csa, TRCOSLSR);
 
-	drvdata->os_lock_model = ETM_OSLSR_OSLM(oslsr);
+	caps->os_lock_model = ETM_OSLSR_OSLM(oslsr);
 }
 
 static void etm_write_os_lock(struct etmv4_drvdata *drvdata,
 			      struct csdev_access *csa, u32 val)
 {
+	const struct etmv4_caps *caps = &drvdata->caps;
+
 	val = !!val;
 
-	switch (drvdata->os_lock_model) {
+	switch (caps->os_lock_model) {
 	case ETM_OSLOCK_PRESENT:
 		etm4x_relaxed_write32(csa, val, TRCOSLAR);
 		break;
@@ -179,7 +183,7 @@ static void etm_write_os_lock(struct etmv4_drvdata *drvdata,
 		break;
 	default:
 		pr_warn_once("CPU%d: Unsupported Trace OSLock model: %x\n",
-			     smp_processor_id(), drvdata->os_lock_model);
+			     smp_processor_id(), caps->os_lock_model);
 		fallthrough;
 	case ETM_OSLOCK_NI:
 		return;
@@ -494,6 +498,7 @@ static int etm4_enable_trace_unit(struct etmv4_drvdata *drvdata)
 static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 {
 	int i, rc;
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 	struct coresight_device *csdev = drvdata->csdev;
 	struct device *etm_dev = &csdev->dev;
@@ -525,14 +530,14 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 	if (etm4x_wait_status(csa, TRCSTATR_IDLE_BIT, 1))
 		dev_err(etm_dev,
 			"timeout while waiting for Idle Trace Status\n");
-	if (drvdata->nr_pe)
+	if (caps->nr_pe)
 		etm4x_relaxed_write32(csa, config->pe_sel, TRCPROCSELR);
 	etm4x_relaxed_write32(csa, config->cfg, TRCCONFIGR);
 	/* nothing specific implemented */
 	etm4x_relaxed_write32(csa, 0x0, TRCAUXCTLR);
 	etm4x_relaxed_write32(csa, config->eventctrl0, TRCEVENTCTL0R);
 	etm4x_relaxed_write32(csa, config->eventctrl1, TRCEVENTCTL1R);
-	if (drvdata->stallctl)
+	if (caps->stallctl)
 		etm4x_relaxed_write32(csa, config->stall_ctrl, TRCSTALLCTLR);
 	etm4x_relaxed_write32(csa, config->ts_ctrl, TRCTSCTLR);
 	etm4x_relaxed_write32(csa, config->syncfreq, TRCSYNCPR);
@@ -542,19 +547,19 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 	etm4x_relaxed_write32(csa, config->vinst_ctrl, TRCVICTLR);
 	etm4x_relaxed_write32(csa, config->viiectlr, TRCVIIECTLR);
 	etm4x_relaxed_write32(csa, config->vissctlr, TRCVISSCTLR);
-	if (drvdata->nr_pe_cmp)
+	if (caps->nr_pe_cmp)
 		etm4x_relaxed_write32(csa, config->vipcssctlr, TRCVIPCSSCTLR);
 
-	if (drvdata->nrseqstate) {
-		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+	if (caps->nrseqstate) {
+		for (i = 0; i < caps->nrseqstate - 1; i++)
 			etm4x_relaxed_write32(csa, config->seq_ctrl[i], TRCSEQEVRn(i));
 
 		etm4x_relaxed_write32(csa, config->seq_rst, TRCSEQRSTEVR);
 		etm4x_relaxed_write32(csa, config->seq_state, TRCSEQSTR);
 	}
-	if (drvdata->numextinsel)
+	if (caps->numextinsel)
 		etm4x_relaxed_write32(csa, config->ext_inp, TRCEXTINSELR);
-	for (i = 0; i < drvdata->nr_cntr; i++) {
+	for (i = 0; i < caps->nr_cntr; i++) {
 		etm4x_relaxed_write32(csa, config->cntrldvr[i], TRCCNTRLDVRn(i));
 		etm4x_relaxed_write32(csa, config->cntr_ctrl[i], TRCCNTCTLRn(i));
 		etm4x_relaxed_write32(csa, config->cntr_val[i], TRCCNTVRn(i));
@@ -564,10 +569,10 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 	 * Resource selector pair 0 is always implemented and reserved.  As
 	 * such start at 2.
 	 */
-	for (i = 2; i < drvdata->nr_resource * 2; i++)
+	for (i = 2; i < caps->nr_resource * 2; i++)
 		etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i));
 
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		/* always clear status bit on restart if using single-shot */
 		if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
 			config->ss_status[i] &= ~TRCSSCSRn_STATUS;
@@ -576,23 +581,23 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 		if (etm4x_sspcicrn_present(drvdata, i))
 			etm4x_relaxed_write32(csa, config->ss_pe_cmp[i], TRCSSPCICRn(i));
 	}
-	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
+	for (i = 0; i < caps->nr_addr_cmp * 2; i++) {
 		etm4x_relaxed_write64(csa, config->addr_val[i], TRCACVRn(i));
 		etm4x_relaxed_write64(csa, config->addr_acc[i], TRCACATRn(i));
 	}
-	for (i = 0; i < drvdata->numcidc; i++)
+	for (i = 0; i < caps->numcidc; i++)
 		etm4x_relaxed_write64(csa, config->ctxid_pid[i], TRCCIDCVRn(i));
 	etm4x_relaxed_write32(csa, config->ctxid_mask0, TRCCIDCCTLR0);
-	if (drvdata->numcidc > 4)
+	if (caps->numcidc > 4)
 		etm4x_relaxed_write32(csa, config->ctxid_mask1, TRCCIDCCTLR1);
 
-	for (i = 0; i < drvdata->numvmidc; i++)
+	for (i = 0; i < caps->numvmidc; i++)
 		etm4x_relaxed_write64(csa, config->vmid_val[i], TRCVMIDCVRn(i));
 	etm4x_relaxed_write32(csa, config->vmid_mask0, TRCVMIDCCTLR0);
-	if (drvdata->numvmidc > 4)
+	if (caps->numvmidc > 4)
 		etm4x_relaxed_write32(csa, config->vmid_mask1, TRCVMIDCCTLR1);
 
-	if (!drvdata->skip_power_up) {
+	if (!caps->skip_power_up) {
 		u32 trcpdcr = etm4x_relaxed_read32(csa, TRCPDCR);
 
 		/*
@@ -668,19 +673,20 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata,
 {
 	int ctridx;
 	int rselector;
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	/* No point in trying if we don't have at least one counter */
-	if (!drvdata->nr_cntr)
+	if (!caps->nr_cntr)
 		return -EINVAL;
 
 	/* Find a counter that hasn't been initialised */
-	for (ctridx = 0; ctridx < drvdata->nr_cntr; ctridx++)
+	for (ctridx = 0; ctridx < caps->nr_cntr; ctridx++)
 		if (config->cntr_val[ctridx] == 0)
 			break;
 
 	/* All the counters have been configured already, bail out */
-	if (ctridx == drvdata->nr_cntr) {
+	if (ctridx == caps->nr_cntr) {
 		pr_debug("%s: no available counter found\n", __func__);
 		return -ENOSPC;
 	}
@@ -696,11 +702,11 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata,
 	 * ETMIDR4 gives the number of resource selector _pairs_, hence multiply
 	 * by 2.
 	 */
-	for (rselector = 2; rselector < drvdata->nr_resource * 2; rselector++)
+	for (rselector = 2; rselector < caps->nr_resource * 2; rselector++)
 		if (!config->res_ctrl[rselector])
 			break;
 
-	if (rselector == drvdata->nr_resource * 2) {
+	if (rselector == caps->nr_resource * 2) {
 		pr_debug("%s: no available resource selector found\n",
 			 __func__);
 		return -ENOSPC;
@@ -751,6 +757,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 {
 	int ret = 0;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 	struct perf_event_attr max_timestamp = {
 		.ATTR_CFG_FLD_timestamp_CFG = U64_MAX,
@@ -790,8 +797,8 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 		cc_threshold = ATTR_CFG_GET_FLD(attr, cc_threshold);
 		if (!cc_threshold)
 			cc_threshold = ETM_CYC_THRESHOLD_DEFAULT;
-		if (cc_threshold < drvdata->ccitmin)
-			cc_threshold = drvdata->ccitmin;
+		if (cc_threshold < caps->ccitmin)
+			cc_threshold = caps->ccitmin;
 		config->ccctlr = cc_threshold;
 	}
 
@@ -839,7 +846,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 	}
 
 	/* return stack - enable if selected and supported */
-	if (ATTR_CFG_GET_FLD(attr, retstack) && drvdata->retstack)
+	if (ATTR_CFG_GET_FLD(attr, retstack) && caps->retstack)
 		/* bit[12], Return stack enable bit */
 		config->cfg |= TRCCONFIGR_RS;
 
@@ -855,7 +862,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 
 	/* branch broadcast - enable if selected and supported */
 	if (ATTR_CFG_GET_FLD(attr, branch_broadcast)) {
-		if (!drvdata->trcbb) {
+		if (!caps->trcbb) {
 			/*
 			 * Missing BB support could cause silent decode errors
 			 * so fail to open if it's not supported.
@@ -1030,6 +1037,7 @@ static void etm4_disable_trace_unit(struct etmv4_drvdata *drvdata)
 static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
 {
 	u32 control;
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
@@ -1038,7 +1046,7 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
 	etm4_cs_unlock(drvdata, csa);
 	etm4_disable_arch_specific(drvdata);
 
-	if (!drvdata->skip_power_up) {
+	if (!caps->skip_power_up) {
 		/* power can be removed from the trace unit now */
 		control = etm4x_relaxed_read32(csa, TRCPDCR);
 		control &= ~TRCPDCR_PU;
@@ -1048,13 +1056,13 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
 	etm4_disable_trace_unit(drvdata);
 
 	/* read the status of the single shot comparators */
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		config->ss_status[i] =
 			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
 	}
 
 	/* read back the current counter values */
-	for (i = 0; i < drvdata->nr_cntr; i++) {
+	for (i = 0; i < caps->nr_cntr; i++) {
 		config->cntr_val[i] =
 			etm4x_relaxed_read32(csa, TRCCNTVRn(i));
 	}
@@ -1352,7 +1360,7 @@ static struct midr_range etm_wrong_ccitmin_cpus[] = {
 	{},
 };
 
-static void etm4_fixup_wrong_ccitmin(struct etmv4_drvdata *drvdata)
+static void etm4_fixup_wrong_ccitmin(struct etmv4_caps *caps)
 {
 	/*
 	 * Erratum affected cpus will read 256 as the minimum
@@ -1362,8 +1370,8 @@ static void etm4_fixup_wrong_ccitmin(struct etmv4_drvdata *drvdata)
 	 * this problem.
 	 */
 	if (is_midr_in_range_list(etm_wrong_ccitmin_cpus)) {
-		if (drvdata->ccitmin == 256)
-			drvdata->ccitmin = 4;
+		if (caps->ccitmin == 256)
+			caps->ccitmin = 4;
 	}
 }
 
@@ -1376,11 +1384,13 @@ static void etm4_init_arch_data(void *info)
 	u32 etmidr5;
 	struct etm4_init_arg *init_arg = info;
 	struct etmv4_drvdata *drvdata;
+	struct etmv4_caps *caps;
 	struct csdev_access *csa;
 	struct device *dev = init_arg->dev;
 	int i;
 
 	drvdata = dev_get_drvdata(init_arg->dev);
+	caps = &drvdata->caps;
 	csa = init_arg->csa;
 
 	/*
@@ -1393,7 +1403,7 @@ static void etm4_init_arch_data(void *info)
 
 	if (!csa->io_mem ||
 	    fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up"))
-		drvdata->skip_power_up = true;
+		caps->skip_power_up = true;
 
 	/* Detect the support for OS Lock before we actually use it */
 	etm_detect_os_lock(drvdata, csa);
@@ -1408,71 +1418,71 @@ static void etm4_init_arch_data(void *info)
 	etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
 
 	/* INSTP0, bits[2:1] P0 tracing support field */
-	drvdata->instrp0 = !!(FIELD_GET(TRCIDR0_INSTP0_MASK, etmidr0) == 0b11);
+	caps->instrp0 = !!(FIELD_GET(TRCIDR0_INSTP0_MASK, etmidr0) == 0b11);
 	/* TRCBB, bit[5] Branch broadcast tracing support bit */
-	drvdata->trcbb = !!(etmidr0 & TRCIDR0_TRCBB);
+	caps->trcbb = !!(etmidr0 & TRCIDR0_TRCBB);
 	/* TRCCOND, bit[6] Conditional instruction tracing support bit */
-	drvdata->trccond = !!(etmidr0 & TRCIDR0_TRCCOND);
+	caps->trccond = !!(etmidr0 & TRCIDR0_TRCCOND);
 	/* TRCCCI, bit[7] Cycle counting instruction bit */
-	drvdata->trccci = !!(etmidr0 & TRCIDR0_TRCCCI);
+	caps->trccci = !!(etmidr0 & TRCIDR0_TRCCCI);
 	/* RETSTACK, bit[9] Return stack bit */
-	drvdata->retstack = !!(etmidr0 & TRCIDR0_RETSTACK);
+	caps->retstack = !!(etmidr0 & TRCIDR0_RETSTACK);
 	/* NUMEVENT, bits[11:10] Number of events field */
-	drvdata->nr_event = FIELD_GET(TRCIDR0_NUMEVENT_MASK, etmidr0);
+	caps->nr_event = FIELD_GET(TRCIDR0_NUMEVENT_MASK, etmidr0);
 	/* QSUPP, bits[16:15] Q element support field */
-	drvdata->q_support = FIELD_GET(TRCIDR0_QSUPP_MASK, etmidr0);
-	if (drvdata->q_support)
-		drvdata->q_filt = !!(etmidr0 & TRCIDR0_QFILT);
+	caps->q_support = FIELD_GET(TRCIDR0_QSUPP_MASK, etmidr0);
+	if (caps->q_support)
+		caps->q_filt = !!(etmidr0 & TRCIDR0_QFILT);
 	/* TSSIZE, bits[28:24] Global timestamp size field */
-	drvdata->ts_size = FIELD_GET(TRCIDR0_TSSIZE_MASK, etmidr0);
+	caps->ts_size = FIELD_GET(TRCIDR0_TSSIZE_MASK, etmidr0);
 
 	/* maximum size of resources */
 	etmidr2 = etm4x_relaxed_read32(csa, TRCIDR2);
 	/* CIDSIZE, bits[9:5] Indicates the Context ID size */
-	drvdata->ctxid_size = FIELD_GET(TRCIDR2_CIDSIZE_MASK, etmidr2);
+	caps->ctxid_size = FIELD_GET(TRCIDR2_CIDSIZE_MASK, etmidr2);
 	/* VMIDSIZE, bits[14:10] Indicates the VMID size */
-	drvdata->vmid_size = FIELD_GET(TRCIDR2_VMIDSIZE_MASK, etmidr2);
+	caps->vmid_size = FIELD_GET(TRCIDR2_VMIDSIZE_MASK, etmidr2);
 	/* CCSIZE, bits[28:25] size of the cycle counter in bits minus 12 */
-	drvdata->ccsize = FIELD_GET(TRCIDR2_CCSIZE_MASK, etmidr2);
+	caps->ccsize = FIELD_GET(TRCIDR2_CCSIZE_MASK, etmidr2);
 
 	etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3);
 	/* CCITMIN, bits[11:0] minimum threshold value that can be programmed */
-	drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
-	etm4_fixup_wrong_ccitmin(drvdata);
+	caps->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
+	etm4_fixup_wrong_ccitmin(caps);
 
 	/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */
-	drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3);
-	drvdata->config.s_ex_level = drvdata->s_ex_level;
+	caps->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3);
+	drvdata->config.s_ex_level = caps->s_ex_level;
 	/* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */
-	drvdata->ns_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_NS_MASK, etmidr3);
+	caps->ns_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_NS_MASK, etmidr3);
 	/*
 	 * TRCERR, bit[24] whether a trace unit can trace a
 	 * system error exception.
 	 */
-	drvdata->trc_error = !!(etmidr3 & TRCIDR3_TRCERR);
+	caps->trc_error = !!(etmidr3 & TRCIDR3_TRCERR);
 	/* SYNCPR, bit[25] implementation has a fixed synchronization period? */
-	drvdata->syncpr = !!(etmidr3 & TRCIDR3_SYNCPR);
+	caps->syncpr = !!(etmidr3 & TRCIDR3_SYNCPR);
 	/* STALLCTL, bit[26] is stall control implemented? */
-	drvdata->stallctl = !!(etmidr3 & TRCIDR3_STALLCTL);
+	caps->stallctl = !!(etmidr3 & TRCIDR3_STALLCTL);
 	/* SYSSTALL, bit[27] implementation can support stall control? */
-	drvdata->sysstall = !!(etmidr3 & TRCIDR3_SYSSTALL);
+	caps->sysstall = !!(etmidr3 & TRCIDR3_SYSSTALL);
 	/*
 	 * NUMPROC - the number of PEs available for tracing, 5bits
 	 *         = TRCIDR3.bits[13:12]bits[30:28]
 	 *  bits[4:3] = TRCIDR3.bits[13:12] (since etm-v4.2, otherwise RES0)
 	 *  bits[3:0] = TRCIDR3.bits[30:28]
 	 */
-	drvdata->nr_pe =  (FIELD_GET(TRCIDR3_NUMPROC_HI_MASK, etmidr3) << 3) |
-			   FIELD_GET(TRCIDR3_NUMPROC_LO_MASK, etmidr3);
+	caps->nr_pe = (FIELD_GET(TRCIDR3_NUMPROC_HI_MASK, etmidr3) << 3) |
+			       FIELD_GET(TRCIDR3_NUMPROC_LO_MASK, etmidr3);
 	/* NOOVERFLOW, bit[31] is trace overflow prevention supported */
-	drvdata->nooverflow = !!(etmidr3 & TRCIDR3_NOOVERFLOW);
+	caps->nooverflow = !!(etmidr3 & TRCIDR3_NOOVERFLOW);
 
 	/* number of resources trace unit supports */
 	etmidr4 = etm4x_relaxed_read32(csa, TRCIDR4);
 	/* NUMACPAIRS, bits[0:3] number of addr comparator pairs for tracing */
-	drvdata->nr_addr_cmp = FIELD_GET(TRCIDR4_NUMACPAIRS_MASK, etmidr4);
+	caps->nr_addr_cmp = FIELD_GET(TRCIDR4_NUMACPAIRS_MASK, etmidr4);
 	/* NUMPC, bits[15:12] number of PE comparator inputs for tracing */
-	drvdata->nr_pe_cmp = FIELD_GET(TRCIDR4_NUMPC_MASK, etmidr4);
+	caps->nr_pe_cmp = FIELD_GET(TRCIDR4_NUMPC_MASK, etmidr4);
 	/*
 	 * NUMRSPAIR, bits[19:16]
 	 * The number of resource pairs conveyed by the HW starts at 0, i.e a
@@ -1483,41 +1493,41 @@ static void etm4_init_arch_data(void *info)
 	 * the default TRUE and FALSE resource selectors are omitted.
 	 * Otherwise for values 0x1 and above the number is N + 1 as per v4.2.
 	 */
-	drvdata->nr_resource = FIELD_GET(TRCIDR4_NUMRSPAIR_MASK, etmidr4);
-	if ((drvdata->arch < ETM_ARCH_V4_3) || (drvdata->nr_resource > 0))
-		drvdata->nr_resource += 1;
+	caps->nr_resource = FIELD_GET(TRCIDR4_NUMRSPAIR_MASK, etmidr4);
+	if ((drvdata->arch < ETM_ARCH_V4_3) || (caps->nr_resource > 0))
+		caps->nr_resource += 1;
 	/*
 	 * NUMSSCC, bits[23:20] the number of single-shot
 	 * comparator control for tracing. Read any status regs as these
 	 * also contain RO capability data.
 	 */
-	drvdata->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	caps->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		drvdata->config.ss_status[i] =
 			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
 	}
 	/* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
-	drvdata->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
+	caps->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
 	/* NUMVMIDC, bits[31:28] number of VMID comparators for tracing */
-	drvdata->numvmidc = FIELD_GET(TRCIDR4_NUMVMIDC_MASK, etmidr4);
+	caps->numvmidc = FIELD_GET(TRCIDR4_NUMVMIDC_MASK, etmidr4);
 
 	etmidr5 = etm4x_relaxed_read32(csa, TRCIDR5);
 	/* NUMEXTIN, bits[8:0] number of external inputs implemented */
-	drvdata->nr_ext_inp = FIELD_GET(TRCIDR5_NUMEXTIN_MASK, etmidr5);
-	drvdata->numextinsel = FIELD_GET(TRCIDR5_NUMEXTINSEL_MASK, etmidr5);
+	caps->nr_ext_inp = FIELD_GET(TRCIDR5_NUMEXTIN_MASK, etmidr5);
+	caps->numextinsel = FIELD_GET(TRCIDR5_NUMEXTINSEL_MASK, etmidr5);
 	/* TRACEIDSIZE, bits[21:16] indicates the trace ID width */
-	drvdata->trcid_size = FIELD_GET(TRCIDR5_TRACEIDSIZE_MASK, etmidr5);
+	caps->trcid_size = FIELD_GET(TRCIDR5_TRACEIDSIZE_MASK, etmidr5);
 	/* ATBTRIG, bit[22] implementation can support ATB triggers? */
-	drvdata->atbtrig = !!(etmidr5 & TRCIDR5_ATBTRIG);
+	caps->atbtrig = !!(etmidr5 & TRCIDR5_ATBTRIG);
 	/*
 	 * LPOVERRIDE, bit[23] implementation supports
 	 * low-power state override
 	 */
-	drvdata->lpoverride = (etmidr5 & TRCIDR5_LPOVERRIDE) && (!drvdata->skip_power_up);
+	caps->lpoverride = (etmidr5 & TRCIDR5_LPOVERRIDE) && (!caps->skip_power_up);
 	/* NUMSEQSTATE, bits[27:25] number of sequencer states implemented */
-	drvdata->nrseqstate = FIELD_GET(TRCIDR5_NUMSEQSTATE_MASK, etmidr5);
+	caps->nrseqstate = FIELD_GET(TRCIDR5_NUMSEQSTATE_MASK, etmidr5);
 	/* NUMCNTR, bits[30:28] number of counters available for tracing */
-	drvdata->nr_cntr = FIELD_GET(TRCIDR5_NUMCNTR_MASK, etmidr5);
+	caps->nr_cntr = FIELD_GET(TRCIDR5_NUMCNTR_MASK, etmidr5);
 
 	coresight_clear_self_claim_tag_unlocked(csa);
 	etm4_cs_lock(drvdata, csa);
@@ -1693,7 +1703,7 @@ static int etm4_get_next_comparator(struct etmv4_drvdata *drvdata, u32 type)
 	 * nr_addr_cmp holds the number of comparator _pair_, so time 2
 	 * for the total number of comparators.
 	 */
-	nr_comparator = drvdata->nr_addr_cmp * 2;
+	nr_comparator = drvdata->caps.nr_addr_cmp * 2;
 
 	/* Go through the tally of comparators looking for a free one. */
 	while (index < nr_comparator) {
@@ -1871,6 +1881,7 @@ static int etm4_dying_cpu(unsigned int cpu)
 static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 {
 	int i, ret = 0;
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_save_state *state;
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa;
@@ -1907,57 +1918,57 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 
 	state = drvdata->save_state;
 
-	if (drvdata->nr_pe)
+	if (caps->nr_pe)
 		state->trcprocselr = etm4x_read32(csa, TRCPROCSELR);
 	state->trcconfigr = etm4x_read32(csa, TRCCONFIGR);
 	state->trcauxctlr = etm4x_read32(csa, TRCAUXCTLR);
 	state->trceventctl0r = etm4x_read32(csa, TRCEVENTCTL0R);
 	state->trceventctl1r = etm4x_read32(csa, TRCEVENTCTL1R);
-	if (drvdata->stallctl)
+	if (caps->stallctl)
 		state->trcstallctlr = etm4x_read32(csa, TRCSTALLCTLR);
 	state->trctsctlr = etm4x_read32(csa, TRCTSCTLR);
 	state->trcsyncpr = etm4x_read32(csa, TRCSYNCPR);
 	state->trcccctlr = etm4x_read32(csa, TRCCCCTLR);
 	state->trcbbctlr = etm4x_read32(csa, TRCBBCTLR);
 	state->trctraceidr = etm4x_read32(csa, TRCTRACEIDR);
-	if (drvdata->q_filt)
+	if (caps->q_filt)
 		state->trcqctlr = etm4x_read32(csa, TRCQCTLR);
 
 	state->trcvictlr = etm4x_read32(csa, TRCVICTLR);
 	state->trcviiectlr = etm4x_read32(csa, TRCVIIECTLR);
 	state->trcvissctlr = etm4x_read32(csa, TRCVISSCTLR);
-	if (drvdata->nr_pe_cmp)
+	if (caps->nr_pe_cmp)
 		state->trcvipcssctlr = etm4x_read32(csa, TRCVIPCSSCTLR);
 
-	if (drvdata->nrseqstate) {
-		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+	if (caps->nrseqstate) {
+		for (i = 0; i < caps->nrseqstate - 1; i++)
 			state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i));
 
 		state->trcseqrstevr = etm4x_read32(csa, TRCSEQRSTEVR);
 		state->trcseqstr = etm4x_read32(csa, TRCSEQSTR);
 	}
 
-	if (drvdata->numextinsel)
+	if (caps->numextinsel)
 		state->trcextinselr = etm4x_read32(csa, TRCEXTINSELR);
 
-	for (i = 0; i < drvdata->nr_cntr; i++) {
+	for (i = 0; i < caps->nr_cntr; i++) {
 		state->trccntrldvr[i] = etm4x_read32(csa, TRCCNTRLDVRn(i));
 		state->trccntctlr[i] = etm4x_read32(csa, TRCCNTCTLRn(i));
 		state->trccntvr[i] = etm4x_read32(csa, TRCCNTVRn(i));
 	}
 
 	/* Resource selector pair 0 is reserved */
-	for (i = 2; i < drvdata->nr_resource * 2; i++)
+	for (i = 2; i < caps->nr_resource * 2; i++)
 		state->trcrsctlr[i] = etm4x_read32(csa, TRCRSCTLRn(i));
 
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		state->trcssccr[i] = etm4x_read32(csa, TRCSSCCRn(i));
 		state->trcsscsr[i] = etm4x_read32(csa, TRCSSCSRn(i));
 		if (etm4x_sspcicrn_present(drvdata, i))
 			state->trcsspcicr[i] = etm4x_read32(csa, TRCSSPCICRn(i));
 	}
 
-	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
+	for (i = 0; i < caps->nr_addr_cmp * 2; i++) {
 		state->trcacvr[i] = etm4x_read64(csa, TRCACVRn(i));
 		state->trcacatr[i] = etm4x_read64(csa, TRCACATRn(i));
 	}
@@ -1969,23 +1980,23 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	 * unit") of ARM IHI 0064D.
 	 */
 
-	for (i = 0; i < drvdata->numcidc; i++)
+	for (i = 0; i < caps->numcidc; i++)
 		state->trccidcvr[i] = etm4x_read64(csa, TRCCIDCVRn(i));
 
-	for (i = 0; i < drvdata->numvmidc; i++)
+	for (i = 0; i < caps->numvmidc; i++)
 		state->trcvmidcvr[i] = etm4x_read64(csa, TRCVMIDCVRn(i));
 
 	state->trccidcctlr0 = etm4x_read32(csa, TRCCIDCCTLR0);
-	if (drvdata->numcidc > 4)
+	if (caps->numcidc > 4)
 		state->trccidcctlr1 = etm4x_read32(csa, TRCCIDCCTLR1);
 
 	state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR0);
-	if (drvdata->numvmidc > 4)
+	if (caps->numvmidc > 4)
 		state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR1);
 
 	state->trcclaimset = etm4x_read32(csa, TRCCLAIMCLR);
 
-	if (!drvdata->skip_power_up)
+	if (!caps->skip_power_up)
 		state->trcpdcr = etm4x_read32(csa, TRCPDCR);
 
 	/* wait for TRCSTATR.IDLE to go up */
@@ -2002,7 +2013,7 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	 * potentially save power on systems that respect the TRCPDCR_PU
 	 * despite requesting software to save/restore state.
 	 */
-	if (!drvdata->skip_power_up)
+	if (!caps->skip_power_up)
 		etm4x_relaxed_write32(csa, (state->trcpdcr & ~TRCPDCR_PU),
 				      TRCPDCR);
 out:
@@ -2029,6 +2040,7 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 {
 	int i;
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_save_state *state = drvdata->save_state;
 	struct csdev_access *csa = &drvdata->csdev->access;
 
@@ -2038,77 +2050,77 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 	etm4_cs_unlock(drvdata, csa);
 	etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);
 
-	if (drvdata->nr_pe)
+	if (caps->nr_pe)
 		etm4x_relaxed_write32(csa, state->trcprocselr, TRCPROCSELR);
 	etm4x_relaxed_write32(csa, state->trcconfigr, TRCCONFIGR);
 	etm4x_relaxed_write32(csa, state->trcauxctlr, TRCAUXCTLR);
 	etm4x_relaxed_write32(csa, state->trceventctl0r, TRCEVENTCTL0R);
 	etm4x_relaxed_write32(csa, state->trceventctl1r, TRCEVENTCTL1R);
-	if (drvdata->stallctl)
+	if (caps->stallctl)
 		etm4x_relaxed_write32(csa, state->trcstallctlr, TRCSTALLCTLR);
 	etm4x_relaxed_write32(csa, state->trctsctlr, TRCTSCTLR);
 	etm4x_relaxed_write32(csa, state->trcsyncpr, TRCSYNCPR);
 	etm4x_relaxed_write32(csa, state->trcccctlr, TRCCCCTLR);
 	etm4x_relaxed_write32(csa, state->trcbbctlr, TRCBBCTLR);
 	etm4x_relaxed_write32(csa, state->trctraceidr, TRCTRACEIDR);
-	if (drvdata->q_filt)
+	if (caps->q_filt)
 		etm4x_relaxed_write32(csa, state->trcqctlr, TRCQCTLR);
 
 	etm4x_relaxed_write32(csa, state->trcvictlr, TRCVICTLR);
 	etm4x_relaxed_write32(csa, state->trcviiectlr, TRCVIIECTLR);
 	etm4x_relaxed_write32(csa, state->trcvissctlr, TRCVISSCTLR);
-	if (drvdata->nr_pe_cmp)
+	if (caps->nr_pe_cmp)
 		etm4x_relaxed_write32(csa, state->trcvipcssctlr, TRCVIPCSSCTLR);
 
-	if (drvdata->nrseqstate) {
-		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+	if (caps->nrseqstate) {
+		for (i = 0; i < caps->nrseqstate - 1; i++)
 			etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i));
 
 		etm4x_relaxed_write32(csa, state->trcseqrstevr, TRCSEQRSTEVR);
 		etm4x_relaxed_write32(csa, state->trcseqstr, TRCSEQSTR);
 	}
-	if (drvdata->numextinsel)
+	if (caps->numextinsel)
 		etm4x_relaxed_write32(csa, state->trcextinselr, TRCEXTINSELR);
 
-	for (i = 0; i < drvdata->nr_cntr; i++) {
+	for (i = 0; i < caps->nr_cntr; i++) {
 		etm4x_relaxed_write32(csa, state->trccntrldvr[i], TRCCNTRLDVRn(i));
 		etm4x_relaxed_write32(csa, state->trccntctlr[i], TRCCNTCTLRn(i));
 		etm4x_relaxed_write32(csa, state->trccntvr[i], TRCCNTVRn(i));
 	}
 
 	/* Resource selector pair 0 is reserved */
-	for (i = 2; i < drvdata->nr_resource * 2; i++)
+	for (i = 2; i < caps->nr_resource * 2; i++)
 		etm4x_relaxed_write32(csa, state->trcrsctlr[i], TRCRSCTLRn(i));
 
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		etm4x_relaxed_write32(csa, state->trcssccr[i], TRCSSCCRn(i));
 		etm4x_relaxed_write32(csa, state->trcsscsr[i], TRCSSCSRn(i));
 		if (etm4x_sspcicrn_present(drvdata, i))
 			etm4x_relaxed_write32(csa, state->trcsspcicr[i], TRCSSPCICRn(i));
 	}
 
-	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
+	for (i = 0; i < caps->nr_addr_cmp * 2; i++) {
 		etm4x_relaxed_write64(csa, state->trcacvr[i], TRCACVRn(i));
 		etm4x_relaxed_write64(csa, state->trcacatr[i], TRCACATRn(i));
 	}
 
-	for (i = 0; i < drvdata->numcidc; i++)
+	for (i = 0; i < caps->numcidc; i++)
 		etm4x_relaxed_write64(csa, state->trccidcvr[i], TRCCIDCVRn(i));
 
-	for (i = 0; i < drvdata->numvmidc; i++)
+	for (i = 0; i < caps->numvmidc; i++)
 		etm4x_relaxed_write64(csa, state->trcvmidcvr[i], TRCVMIDCVRn(i));
 
 	etm4x_relaxed_write32(csa, state->trccidcctlr0, TRCCIDCCTLR0);
-	if (drvdata->numcidc > 4)
+	if (caps->numcidc > 4)
 		etm4x_relaxed_write32(csa, state->trccidcctlr1, TRCCIDCCTLR1);
 
 	etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR0);
-	if (drvdata->numvmidc > 4)
+	if (caps->numvmidc > 4)
 		etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR1);
 
 	etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);
 
-	if (!drvdata->skip_power_up)
+	if (!caps->skip_power_up)
 		etm4x_relaxed_write32(csa, state->trcpdcr, TRCPDCR);
 
 	/*
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 0e1ad175aa1e..7de3c58a47b4 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -62,8 +62,9 @@ static ssize_t nr_pe_cmp_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_pe_cmp;
+	val = caps->nr_pe_cmp;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_pe_cmp);
@@ -74,8 +75,9 @@ static ssize_t nr_addr_cmp_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_addr_cmp;
+	val = caps->nr_addr_cmp;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_addr_cmp);
@@ -86,8 +88,9 @@ static ssize_t nr_cntr_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_cntr;
+	val = caps->nr_cntr;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_cntr);
@@ -98,8 +101,9 @@ static ssize_t nr_ext_inp_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_ext_inp;
+	val = caps->nr_ext_inp;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_ext_inp);
@@ -110,8 +114,9 @@ static ssize_t numcidc_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->numcidc;
+	val = caps->numcidc;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(numcidc);
@@ -122,8 +127,9 @@ static ssize_t numvmidc_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->numvmidc;
+	val = caps->numvmidc;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(numvmidc);
@@ -134,8 +140,9 @@ static ssize_t nrseqstate_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nrseqstate;
+	val = caps->nrseqstate;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nrseqstate);
@@ -146,8 +153,9 @@ static ssize_t nr_resource_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_resource;
+	val = caps->nr_resource;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_resource);
@@ -158,8 +166,9 @@ static ssize_t nr_ss_cmp_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 
-	val = drvdata->nr_ss_cmp;
+	val = caps->nr_ss_cmp;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
 static DEVICE_ATTR_RO(nr_ss_cmp);
@@ -171,6 +180,7 @@ static ssize_t reset_store(struct device *dev,
 	int i;
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -200,7 +210,7 @@ static ssize_t reset_store(struct device *dev,
 	config->stall_ctrl = 0x0;
 
 	/* Reset trace synchronization period  to 2^8 = 256 bytes*/
-	if (drvdata->syncpr == false)
+	if (!caps->syncpr)
 		config->syncfreq = 0x8;
 
 	/*
@@ -209,7 +219,7 @@ static ssize_t reset_store(struct device *dev,
 	 * each trace run.
 	 */
 	config->vinst_ctrl = FIELD_PREP(TRCVICTLR_EVENT_MASK, 0x01);
-	if (drvdata->nr_addr_cmp > 0) {
+	if (caps->nr_addr_cmp > 0) {
 		config->mode |= ETM_MODE_VIEWINST_STARTSTOP;
 		/* SSSTATUS, bit[9] */
 		config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
@@ -223,7 +233,7 @@ static ssize_t reset_store(struct device *dev,
 	config->vipcssctlr = 0x0;
 
 	/* Disable seq events */
-	for (i = 0; i < drvdata->nrseqstate-1; i++)
+	for (i = 0; i < caps->nrseqstate - 1; i++)
 		config->seq_ctrl[i] = 0x0;
 	config->seq_rst = 0x0;
 	config->seq_state = 0x0;
@@ -232,38 +242,38 @@ static ssize_t reset_store(struct device *dev,
 	config->ext_inp = 0x0;
 
 	config->cntr_idx = 0x0;
-	for (i = 0; i < drvdata->nr_cntr; i++) {
+	for (i = 0; i < caps->nr_cntr; i++) {
 		config->cntrldvr[i] = 0x0;
 		config->cntr_ctrl[i] = 0x0;
 		config->cntr_val[i] = 0x0;
 	}
 
 	config->res_idx = 0x0;
-	for (i = 2; i < 2 * drvdata->nr_resource; i++)
+	for (i = 2; i < 2 * caps->nr_resource; i++)
 		config->res_ctrl[i] = 0x0;
 
 	config->ss_idx = 0x0;
-	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+	for (i = 0; i < caps->nr_ss_cmp; i++) {
 		config->ss_ctrl[i] = 0x0;
 		config->ss_pe_cmp[i] = 0x0;
 	}
 
 	config->addr_idx = 0x0;
-	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
+	for (i = 0; i < caps->nr_addr_cmp * 2; i++) {
 		config->addr_val[i] = 0x0;
 		config->addr_acc[i] = 0x0;
 		config->addr_type[i] = ETM_ADDR_TYPE_NONE;
 	}
 
 	config->ctxid_idx = 0x0;
-	for (i = 0; i < drvdata->numcidc; i++)
+	for (i = 0; i < caps->numcidc; i++)
 		config->ctxid_pid[i] = 0x0;
 
 	config->ctxid_mask0 = 0x0;
 	config->ctxid_mask1 = 0x0;
 
 	config->vmid_idx = 0x0;
-	for (i = 0; i < drvdata->numvmidc; i++)
+	for (i = 0; i < caps->numvmidc; i++)
 		config->vmid_val[i] = 0x0;
 	config->vmid_mask0 = 0x0;
 	config->vmid_mask1 = 0x0;
@@ -297,6 +307,7 @@ static ssize_t mode_store(struct device *dev,
 {
 	unsigned long val, mode;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -305,7 +316,7 @@ static ssize_t mode_store(struct device *dev,
 	raw_spin_lock(&drvdata->spinlock);
 	config->mode = val & ETMv4_MODE_ALL;
 
-	if (drvdata->instrp0 == true) {
+	if (caps->instrp0) {
 		/* start by clearing instruction P0 field */
 		config->cfg  &= ~TRCCONFIGR_INSTP0_LOAD_STORE;
 		if (config->mode & ETM_MODE_LOAD)
@@ -323,45 +334,44 @@ static ssize_t mode_store(struct device *dev,
 	}
 
 	/* bit[3], Branch broadcast mode */
-	if ((config->mode & ETM_MODE_BB) && (drvdata->trcbb == true))
+	if ((config->mode & ETM_MODE_BB) && (caps->trcbb))
 		config->cfg |= TRCCONFIGR_BB;
 	else
 		config->cfg &= ~TRCCONFIGR_BB;
 
 	/* bit[4], Cycle counting instruction trace bit */
 	if ((config->mode & ETMv4_MODE_CYCACC) &&
-		(drvdata->trccci == true))
+		(caps->trccci == true))
 		config->cfg |= TRCCONFIGR_CCI;
 	else
 		config->cfg &= ~TRCCONFIGR_CCI;
 
 	/* bit[6], Context ID tracing bit */
-	if ((config->mode & ETMv4_MODE_CTXID) && (drvdata->ctxid_size))
+	if ((config->mode & ETMv4_MODE_CTXID) && (caps->ctxid_size))
 		config->cfg |= TRCCONFIGR_CID;
 	else
 		config->cfg &= ~TRCCONFIGR_CID;
 
-	if ((config->mode & ETM_MODE_VMID) && (drvdata->vmid_size))
+	if ((config->mode & ETM_MODE_VMID) && (caps->vmid_size))
 		config->cfg |= TRCCONFIGR_VMID;
 	else
 		config->cfg &= ~TRCCONFIGR_VMID;
 
 	/* bits[10:8], Conditional instruction tracing bit */
 	mode = ETM_MODE_COND(config->mode);
-	if (drvdata->trccond == true) {
+	if (caps->trccond) {
 		config->cfg &= ~TRCCONFIGR_COND_MASK;
 		config->cfg |= mode << __bf_shf(TRCCONFIGR_COND_MASK);
 	}
 
 	/* bit[11], Global timestamp tracing bit */
-	if ((config->mode & ETMv4_MODE_TIMESTAMP) && (drvdata->ts_size))
+	if ((config->mode & ETMv4_MODE_TIMESTAMP) && (caps->ts_size))
 		config->cfg |= TRCCONFIGR_TS;
 	else
 		config->cfg &= ~TRCCONFIGR_TS;
 
 	/* bit[12], Return stack enable bit */
-	if ((config->mode & ETM_MODE_RETURNSTACK) &&
-					(drvdata->retstack == true))
+	if ((config->mode & ETM_MODE_RETURNSTACK) && (caps->retstack))
 		config->cfg |= TRCCONFIGR_RS;
 	else
 		config->cfg &= ~TRCCONFIGR_RS;
@@ -375,31 +385,29 @@ static ssize_t mode_store(struct device *dev,
 	 * Always set the low bit for any requested mode. Valid combos are
 	 * 0b00, 0b01 and 0b11.
 	 */
-	if (mode && drvdata->q_support)
+	if (mode && caps->q_support)
 		config->cfg |= TRCCONFIGR_QE_W_COUNTS;
 	/*
 	 * if supported, Q elements with and without instruction
 	 * counts are enabled
 	 */
-	if ((mode & BIT(1)) && (drvdata->q_support & BIT(1)))
+	if ((mode & BIT(1)) && (caps->q_support & BIT(1)))
 		config->cfg |= TRCCONFIGR_QE_WO_COUNTS;
 
 	/* bit[11], AMBA Trace Bus (ATB) trigger enable bit */
-	if ((config->mode & ETM_MODE_ATB_TRIGGER) &&
-	    (drvdata->atbtrig == true))
+	if ((config->mode & ETM_MODE_ATB_TRIGGER) && (caps->atbtrig))
 		config->eventctrl1 |= TRCEVENTCTL1R_ATB;
 	else
 		config->eventctrl1 &= ~TRCEVENTCTL1R_ATB;
 
 	/* bit[12], Low-power state behavior override bit */
-	if ((config->mode & ETM_MODE_LPOVERRIDE) &&
-	    (drvdata->lpoverride == true))
+	if ((config->mode & ETM_MODE_LPOVERRIDE) && (caps->lpoverride))
 		config->eventctrl1 |= TRCEVENTCTL1R_LPOVERRIDE;
 	else
 		config->eventctrl1 &= ~TRCEVENTCTL1R_LPOVERRIDE;
 
 	/* bit[8], Instruction stall bit */
-	if ((config->mode & ETM_MODE_ISTALL_EN) && (drvdata->stallctl == true))
+	if ((config->mode & ETM_MODE_ISTALL_EN) && (caps->stallctl))
 		config->stall_ctrl |= TRCSTALLCTLR_ISTALL;
 	else
 		config->stall_ctrl &= ~TRCSTALLCTLR_ISTALL;
@@ -411,8 +419,7 @@ static ssize_t mode_store(struct device *dev,
 		config->stall_ctrl &= ~TRCSTALLCTLR_INSTPRIORITY;
 
 	/* bit[13], Trace overflow prevention bit */
-	if ((config->mode & ETM_MODE_NOOVERFLOW) &&
-		(drvdata->nooverflow == true))
+	if ((config->mode & ETM_MODE_NOOVERFLOW) && (caps->nooverflow))
 		config->stall_ctrl |= TRCSTALLCTLR_NOOVERFLOW;
 	else
 		config->stall_ctrl &= ~TRCSTALLCTLR_NOOVERFLOW;
@@ -430,8 +437,7 @@ static ssize_t mode_store(struct device *dev,
 		config->vinst_ctrl &= ~TRCVICTLR_TRCRESET;
 
 	/* bit[11], Whether a trace unit must trace a system error exception */
-	if ((config->mode & ETM_MODE_TRACE_ERR) &&
-		(drvdata->trc_error == true))
+	if ((config->mode & ETM_MODE_TRACE_ERR) && (caps->trc_error))
 		config->vinst_ctrl |= TRCVICTLR_TRCERR;
 	else
 		config->vinst_ctrl &= ~TRCVICTLR_TRCERR;
@@ -463,13 +469,14 @@ static ssize_t pe_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
-	if (val > drvdata->nr_pe) {
+	if (val > caps->nr_pe) {
 		raw_spin_unlock(&drvdata->spinlock);
 		return -EINVAL;
 	}
@@ -498,13 +505,14 @@ static ssize_t event_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
-	switch (drvdata->nr_event) {
+	switch (caps->nr_event) {
 	case 0x0:
 		/* EVENT0, bits[7:0] */
 		config->eventctrl0 = val & 0xFF;
@@ -547,6 +555,7 @@ static ssize_t event_instren_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -555,7 +564,7 @@ static ssize_t event_instren_store(struct device *dev,
 	raw_spin_lock(&drvdata->spinlock);
 	/* start by clearing all instruction event enable bits */
 	config->eventctrl1 &= ~TRCEVENTCTL1R_INSTEN_MASK;
-	switch (drvdata->nr_event) {
+	switch (caps->nr_event) {
 	case 0x0:
 		/* generate Event element for event 1 */
 		config->eventctrl1 |= val & TRCEVENTCTL1R_INSTEN_1;
@@ -603,11 +612,12 @@ static ssize_t event_ts_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (!drvdata->ts_size)
+	if (!caps->ts_size)
 		return -EINVAL;
 
 	config->ts_ctrl = val & ETMv4_EVENT_MASK;
@@ -633,11 +643,12 @@ static ssize_t syncfreq_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (drvdata->syncpr == true)
+	if (caps->syncpr)
 		return -EINVAL;
 
 	config->syncfreq = val & ETMv4_SYNC_MASK;
@@ -663,6 +674,7 @@ static ssize_t cyc_threshold_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -670,7 +682,7 @@ static ssize_t cyc_threshold_store(struct device *dev,
 
 	/* mask off max threshold before checking min value */
 	val &= ETM_CYC_THRESHOLD_MASK;
-	if (val < drvdata->ccitmin)
+	if (val < caps->ccitmin)
 		return -EINVAL;
 
 	config->ccctlr = val;
@@ -696,13 +708,14 @@ static ssize_t bb_ctrl_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (drvdata->trcbb == false)
+	if (!caps->trcbb)
 		return -EINVAL;
-	if (!drvdata->nr_addr_cmp)
+	if (!caps->nr_addr_cmp)
 		return -EINVAL;
 
 	/*
@@ -768,6 +781,7 @@ static ssize_t s_exlevel_vinst_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -777,7 +791,7 @@ static ssize_t s_exlevel_vinst_store(struct device *dev,
 	/* clear all EXLEVEL_S bits  */
 	config->vinst_ctrl &= ~TRCVICTLR_EXLEVEL_S_MASK;
 	/* enable instruction tracing for corresponding exception level */
-	val &= drvdata->s_ex_level;
+	val &= caps->s_ex_level;
 	config->vinst_ctrl |= val << __bf_shf(TRCVICTLR_EXLEVEL_S_MASK);
 	raw_spin_unlock(&drvdata->spinlock);
 	return size;
@@ -803,6 +817,7 @@ static ssize_t ns_exlevel_vinst_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -812,7 +827,7 @@ static ssize_t ns_exlevel_vinst_store(struct device *dev,
 	/* clear EXLEVEL_NS bits  */
 	config->vinst_ctrl &= ~TRCVICTLR_EXLEVEL_NS_MASK;
 	/* enable instruction tracing for corresponding exception level */
-	val &= drvdata->ns_ex_level;
+	val &= caps->ns_ex_level;
 	config->vinst_ctrl |= val << __bf_shf(TRCVICTLR_EXLEVEL_NS_MASK);
 	raw_spin_unlock(&drvdata->spinlock);
 	return size;
@@ -837,11 +852,12 @@ static ssize_t addr_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->nr_addr_cmp * 2)
+	if (val >= caps->nr_addr_cmp * 2)
 		return -EINVAL;
 
 	/*
@@ -1060,6 +1076,7 @@ static ssize_t addr_start_store(struct device *dev,
 	u8 idx;
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -1067,7 +1084,7 @@ static ssize_t addr_start_store(struct device *dev,
 
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
-	if (!drvdata->nr_addr_cmp) {
+	if (!caps->nr_addr_cmp) {
 		raw_spin_unlock(&drvdata->spinlock);
 		return -EINVAL;
 	}
@@ -1115,6 +1132,7 @@ static ssize_t addr_stop_store(struct device *dev,
 	u8 idx;
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -1122,7 +1140,7 @@ static ssize_t addr_stop_store(struct device *dev,
 
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->addr_idx;
-	if (!drvdata->nr_addr_cmp) {
+	if (!caps->nr_addr_cmp) {
 		raw_spin_unlock(&drvdata->spinlock);
 		return -EINVAL;
 	}
@@ -1167,6 +1185,7 @@ static ssize_t addr_ctxtype_store(struct device *dev,
 	u8 idx;
 	char str[10] = "";
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (strlen(buf) >= 10)
@@ -1181,13 +1200,13 @@ static ssize_t addr_ctxtype_store(struct device *dev,
 		config->addr_acc[idx] &= ~TRCACATRn_CONTEXTTYPE_MASK;
 	else if (!strcmp(str, "ctxid")) {
 		/* 0b01 The trace unit performs a Context ID */
-		if (drvdata->numcidc) {
+		if (caps->numcidc) {
 			config->addr_acc[idx] |= TRCACATRn_CONTEXTTYPE_CTXID;
 			config->addr_acc[idx] &= ~TRCACATRn_CONTEXTTYPE_VMID;
 		}
 	} else if (!strcmp(str, "vmid")) {
 		/* 0b10 The trace unit performs a VMID */
-		if (drvdata->numvmidc) {
+		if (caps->numvmidc) {
 			config->addr_acc[idx] &= ~TRCACATRn_CONTEXTTYPE_CTXID;
 			config->addr_acc[idx] |= TRCACATRn_CONTEXTTYPE_VMID;
 		}
@@ -1196,9 +1215,9 @@ static ssize_t addr_ctxtype_store(struct device *dev,
 		 * 0b11 The trace unit performs a Context ID
 		 * comparison and a VMID
 		 */
-		if (drvdata->numcidc)
+		if (caps->numcidc)
 			config->addr_acc[idx] |= TRCACATRn_CONTEXTTYPE_CTXID;
-		if (drvdata->numvmidc)
+		if (caps->numvmidc)
 			config->addr_acc[idx] |= TRCACATRn_CONTEXTTYPE_VMID;
 	}
 	raw_spin_unlock(&drvdata->spinlock);
@@ -1230,14 +1249,15 @@ static ssize_t addr_context_store(struct device *dev,
 	u8 idx;
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if ((drvdata->numcidc <= 1) && (drvdata->numvmidc <= 1))
+	if ((caps->numcidc <= 1) && (caps->numvmidc <= 1))
 		return -EINVAL;
-	if (val >=  (drvdata->numcidc >= drvdata->numvmidc ?
-		     drvdata->numcidc : drvdata->numvmidc))
+	if (val >=  (caps->numcidc >= caps->numvmidc ?
+		     caps->numcidc : caps->numvmidc))
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
@@ -1348,9 +1368,10 @@ static ssize_t vinst_pe_cmp_start_stop_show(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
-	if (!drvdata->nr_pe_cmp)
+	if (!caps->nr_pe_cmp)
 		return -EINVAL;
 	val = config->vipcssctlr;
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
@@ -1361,11 +1382,12 @@ static ssize_t vinst_pe_cmp_start_stop_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (!drvdata->nr_pe_cmp)
+	if (!caps->nr_pe_cmp)
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
@@ -1393,13 +1415,14 @@ static ssize_t seq_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
-	if (!drvdata->nrseqstate)
+	if (!caps->nrseqstate)
 		return -ENOTSUPP;
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->nrseqstate - 1)
+	if (val >= caps->nrseqstate - 1)
 		return -EINVAL;
 
 	/*
@@ -1431,11 +1454,12 @@ static ssize_t seq_state_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->nrseqstate)
+	if (val >= caps->nrseqstate)
 		return -EINVAL;
 
 	config->seq_state = val;
@@ -1498,11 +1522,12 @@ static ssize_t seq_reset_event_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (!(drvdata->nrseqstate))
+	if (!(caps->nrseqstate))
 		return -EINVAL;
 
 	config->seq_rst = val & ETMv4_EVENT_MASK;
@@ -1528,11 +1553,12 @@ static ssize_t cntr_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->nr_cntr)
+	if (val >= caps->nr_cntr)
 		return -EINVAL;
 
 	/*
@@ -1676,6 +1702,7 @@ static ssize_t res_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
@@ -1684,7 +1711,7 @@ static ssize_t res_idx_store(struct device *dev,
 	 * Resource selector pair 0 is always implemented and reserved,
 	 * namely an idx with 0 and 1 is illegal.
 	 */
-	if ((val < 2) || (val >= 2 * drvdata->nr_resource))
+	if ((val < 2) || (val >= 2 * caps->nr_resource))
 		return -EINVAL;
 
 	/*
@@ -1758,11 +1785,12 @@ static ssize_t sshot_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->nr_ss_cmp)
+	if (val >= caps->nr_ss_cmp)
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
@@ -1876,11 +1904,12 @@ static ssize_t ctxid_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->numcidc)
+	if (val >= caps->numcidc)
 		return -EINVAL;
 
 	/*
@@ -1924,6 +1953,7 @@ static ssize_t ctxid_pid_store(struct device *dev,
 	u8 idx;
 	unsigned long pid;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	/*
@@ -1943,7 +1973,7 @@ static ssize_t ctxid_pid_store(struct device *dev,
 	 * ctxid comparator is implemented and ctxid is greater than 0 bits
 	 * in length
 	 */
-	if (!drvdata->ctxid_size || !drvdata->numcidc)
+	if (!caps->ctxid_size || !caps->numcidc)
 		return -EINVAL;
 	if (kstrtoul(buf, 16, &pid))
 		return -EINVAL;
@@ -1985,6 +2015,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	u8 i, j, maskbyte;
 	unsigned long val1, val2, mask;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 	int nr_inputs;
 
@@ -2000,11 +2031,11 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	 * ctxid comparator is implemented and ctxid is greater than 0 bits
 	 * in length
 	 */
-	if (!drvdata->ctxid_size || !drvdata->numcidc)
+	if (!caps->ctxid_size || !caps->numcidc)
 		return -EINVAL;
 	/* one mask if <= 4 comparators, two for up to 8 */
 	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
-	if ((drvdata->numcidc > 4) && (nr_inputs != 2))
+	if ((caps->numcidc > 4) && (nr_inputs != 2))
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
@@ -2012,7 +2043,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	 * each byte[0..3] controls mask value applied to ctxid
 	 * comparator[0..3]
 	 */
-	switch (drvdata->numcidc) {
+	switch (caps->numcidc) {
 	case 0x1:
 		/* COMP0, bits[7:0] */
 		config->ctxid_mask0 = val1 & 0xFF;
@@ -2059,7 +2090,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
 	 * of ctxid comparator0 value (corresponding to byte 0) register.
 	 */
 	mask = config->ctxid_mask0;
-	for (i = 0; i < drvdata->numcidc; i++) {
+	for (i = 0; i < caps->numcidc; i++) {
 		/* mask value of corresponding ctxid comparator */
 		maskbyte = mask & ETMv4_EVENT_MASK;
 		/*
@@ -2102,11 +2133,12 @@ static ssize_t vmid_idx_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
-	if (val >= drvdata->numvmidc)
+	if (val >= caps->numvmidc)
 		return -EINVAL;
 
 	/*
@@ -2147,6 +2179,7 @@ static ssize_t vmid_val_store(struct device *dev,
 {
 	unsigned long val;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 
 	/*
@@ -2160,7 +2193,7 @@ static ssize_t vmid_val_store(struct device *dev,
 	 * only implemented when vmid tracing is enabled, i.e. at least one
 	 * vmid comparator is implemented and at least 8 bit vmid size
 	 */
-	if (!drvdata->vmid_size || !drvdata->numvmidc)
+	if (!caps->vmid_size || !caps->numvmidc)
 		return -EINVAL;
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
@@ -2200,6 +2233,7 @@ static ssize_t vmid_masks_store(struct device *dev,
 	u8 i, j, maskbyte;
 	unsigned long val1, val2, mask;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	const struct etmv4_caps *caps = &drvdata->caps;
 	struct etmv4_config *config = &drvdata->config;
 	int nr_inputs;
 
@@ -2214,11 +2248,11 @@ static ssize_t vmid_masks_store(struct device *dev,
 	 * only implemented when vmid tracing is enabled, i.e. at least one
 	 * vmid comparator is implemented and at least 8 bit vmid size
 	 */
-	if (!drvdata->vmid_size || !drvdata->numvmidc)
+	if (!caps->vmid_size || !caps->numvmidc)
 		return -EINVAL;
 	/* one mask if <= 4 comparators, two for up to 8 */
 	nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
-	if ((drvdata->numvmidc > 4) && (nr_inputs != 2))
+	if ((caps->numvmidc > 4) && (nr_inputs != 2))
 		return -EINVAL;
 
 	raw_spin_lock(&drvdata->spinlock);
@@ -2227,7 +2261,7 @@ static ssize_t vmid_masks_store(struct device *dev,
 	 * each byte[0..3] controls mask value applied to vmid
 	 * comparator[0..3]
 	 */
-	switch (drvdata->numvmidc) {
+	switch (caps->numvmidc) {
 	case 0x1:
 		/* COMP0, bits[7:0] */
 		config->vmid_mask0 = val1 & 0xFF;
@@ -2275,7 +2309,7 @@ static ssize_t vmid_masks_store(struct device *dev,
 	 * of vmid comparator0 value (corresponding to byte 0) register.
 	 */
 	mask = config->vmid_mask0;
-	for (i = 0; i < drvdata->numvmidc; i++) {
+	for (i = 0; i < caps->numvmidc; i++) {
 		/* mask value of corresponding vmid comparator */
 		maskbyte = mask & ETMv4_EVENT_MASK;
 		/*
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 89d81ce4e04e..8168676f2945 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -812,6 +812,95 @@ enum etm_impdef_type {
 	ETM4_IMPDEF_FEATURE_MAX,
 };
 
+/**
+ * struct etmv4_caps - specifics ETM capabilities
+ * @nr_pe:	The number of processing entity available for tracing.
+ * @nr_pe_cmp:	The number of processing entity comparator inputs that are
+ *		available for tracing.
+ * @nr_addr_cmp:Number of pairs of address comparators available
+ *		as found in ETMIDR4 0-3.
+ * @nr_cntr:    Number of counters as found in ETMIDR5 bit 28-30.
+ * @nr_ext_inp: Number of external input.
+ * @numcidc:	Number of contextID comparators.
+ * @numextinsel: Number of external input selector resources.
+ * @numvmidc:	Number of VMID comparators.
+ * @nrseqstate: The number of sequencer states that are implemented.
+ * @nr_event:	Indicates how many events the trace unit support.
+ * @nr_resource:The number of resource selection pairs available for tracing.
+ * @nr_ss_cmp:	Number of single-shot comparator controls that are available.
+ * @trcid_size: Indicates the trace ID width.
+ * @ts_size:	Global timestamp size field.
+ * @ctxid_size:	Size of the context ID field to consider.
+ * @vmid_size:	Size of the VM ID comparator to consider.
+ * @ccsize:	Indicates the size of the cycle counter in bits.
+ * @ccitmin:	minimum value that can be programmed in
+ * @s_ex_level:	In secure state, indicates whether instruction tracing is
+ *		supported for the corresponding Exception level.
+ * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
+ *		supported for the corresponding Exception level.
+ * @q_support:	Q element support characteristics.
+ * @os_lock_model: OSLock model.
+ * @instrp0:	Tracing of load and store instructions
+ *		as P0 elements is supported.
+ * @q_filt:	Q element filtering support, if Q elements are supported.
+ * @trcbb:	Indicates if the trace unit supports branch broadcast tracing.
+ * @trccond:	If the trace unit supports conditional
+ *		instruction tracing.
+ * @retstack:	Indicates if the implementation supports a return stack.
+ * @trccci:	Indicates if the trace unit supports cycle counting
+ *		for instruction.
+ * @trc_error:	Whether a trace unit can trace a system
+ *		error exception.
+ * @syncpr:	Indicates if an implementation has a fixed
+ *		synchronization period.
+ * @stallctl:	If functionality that prevents trace unit buffer overflows
+ *		is available.
+ * @sysstall:	Does the system support stall control of the PE?
+ * @nooverflow:	Indicate if overflow prevention is supported.
+ * @atbtrig:	If the implementation can support ATB triggers
+ * @lpoverride:	If the implementation can support low-power state over.
+ * @skip_power_up: Indicates if an implementation can skip powering up
+ *		   the trace unit.
+ */
+struct etmv4_caps {
+	u8	nr_pe;
+	u8	nr_pe_cmp;
+	u8	nr_addr_cmp;
+	u8	nr_cntr;
+	u8	nr_ext_inp;
+	u8	numcidc;
+	u8	numextinsel;
+	u8	numvmidc;
+	u8	nrseqstate;
+	u8	nr_event;
+	u8	nr_resource;
+	u8	nr_ss_cmp;
+	u8	trcid_size;
+	u8	ts_size;
+	u8	ctxid_size;
+	u8	vmid_size;
+	u8	ccsize;
+	u16	ccitmin;
+	u8	s_ex_level;
+	u8	ns_ex_level;
+	u8	q_support;
+	u8	os_lock_model;
+	bool	instrp0 : 1;
+	bool	q_filt : 1;
+	bool	trcbb : 1;
+	bool	trccond : 1;
+	bool	retstack : 1;
+	bool	trccci : 1;
+	bool	trc_error : 1;
+	bool	syncpr : 1;
+	bool	stallctl : 1;
+	bool	sysstall : 1;
+	bool	nooverflow : 1;
+	bool	atbtrig : 1;
+	bool	lpoverride : 1;
+	bool	skip_power_up : 1;
+};
+
 /**
  * struct etmv4_config - configuration information related to an ETMv4
  * @mode:	Controls various modes supported by this ETM.
@@ -819,8 +908,8 @@ enum etm_impdef_type {
  * @cfg:	Controls the tracing options.
  * @eventctrl0: Controls the tracing of arbitrary events.
  * @eventctrl1: Controls the behavior of the events that @event_ctrl0 selects.
- * @stallctl:	If functionality that prevents trace unit buffer overflows
- *		is available.
+ * @stall_ctrl:	Enables trace unit functionality that prevents trace
+ *		unit buffer overflows.
  * @ts_ctrl:	Controls the insertion of global timestamps in the
  *		trace streams.
  * @syncfreq:	Controls how often trace synchronization requests occur.
@@ -971,61 +1060,17 @@ struct etmv4_save_state {
  * @mode:	This tracer's mode, i.e sysFS, Perf or disabled.
  * @cpu:        The cpu this component is affined to.
  * @arch:       ETM architecture version.
- * @nr_pe:	The number of processing entity available for tracing.
- * @nr_pe_cmp:	The number of processing entity comparator inputs that are
- *		available for tracing.
- * @nr_addr_cmp:Number of pairs of address comparators available
- *		as found in ETMIDR4 0-3.
- * @nr_cntr:    Number of counters as found in ETMIDR5 bit 28-30.
- * @nr_ext_inp: Number of external input.
- * @numcidc:	Number of contextID comparators.
- * @numvmidc:	Number of VMID comparators.
- * @nrseqstate: The number of sequencer states that are implemented.
- * @nr_event:	Indicates how many events the trace unit support.
- * @nr_resource:The number of resource selection pairs available for tracing.
- * @nr_ss_cmp:	Number of single-shot comparator controls that are available.
+ * @caps:	ETM capabilities.
  * @trcid:	value of the current ID for this component.
- * @trcid_size: Indicates the trace ID width.
- * @ts_size:	Global timestamp size field.
- * @ctxid_size:	Size of the context ID field to consider.
- * @vmid_size:	Size of the VM ID comparator to consider.
- * @ccsize:	Indicates the size of the cycle counter in bits.
- * @ccitmin:	minimum value that can be programmed in
- * @s_ex_level:	In secure state, indicates whether instruction tracing is
- *		supported for the corresponding Exception level.
- * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
- *		supported for the corresponding Exception level.
  * @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.
- * @instrp0:	Tracing of load and store instructions
- *		as P0 elements is supported.
- * @q_filt:	Q element filtering support, if Q elements are supported.
- * @trcbb:	Indicates if the trace unit supports branch broadcast tracing.
- * @trccond:	If the trace unit supports conditional
- *		instruction tracing.
- * @retstack:	Indicates if the implementation supports a return stack.
- * @trccci:	Indicates if the trace unit supports cycle counting
- *		for instruction.
- * @q_support:	Q element support characteristics.
- * @trc_error:	Whether a trace unit can trace a system
- *		error exception.
- * @syncpr:	Indicates if an implementation has a fixed
- *		synchronization period.
- * @stall_ctrl:	Enables trace unit functionality that prevents trace
- *		unit buffer overflows.
- * @sysstall:	Does the system support stall control of the PE?
- * @nooverflow:	Indicate if overflow prevention is supported.
- * @atbtrig:	If the implementation can support ATB triggers
- * @lpoverride:	If the implementation can support low-power state over.
  * @trfcr:	If the CPU supports FEAT_TRF, value of the TRFCR_ELx that
  *		allows tracing at all ELs. We don't want to compute this
  *		at runtime, due to the additional setting of TRFCR_CX when
  *		in EL2. Otherwise, 0.
  * @config:	structure holding configuration parameters.
  * @save_state:	State to be preserved across power loss
- * @skip_power_up: Indicates if an implementation can skip powering up
- *		   the trace unit.
  * @paused:	Indicates if the trace unit is paused.
  * @arch_features: Bitmap of arch features of etmv4 devices.
  */
@@ -1037,46 +1082,11 @@ struct etmv4_drvdata {
 	raw_spinlock_t			spinlock;
 	int				cpu;
 	u8				arch;
-	u8				nr_pe;
-	u8				nr_pe_cmp;
-	u8				nr_addr_cmp;
-	u8				nr_cntr;
-	u8				nr_ext_inp;
-	u8				numcidc;
-	u8				numextinsel;
-	u8				numvmidc;
-	u8				nrseqstate;
-	u8				nr_event;
-	u8				nr_resource;
-	u8				nr_ss_cmp;
+	struct etmv4_caps		caps;
 	u8				trcid;
-	u8				trcid_size;
-	u8				ts_size;
-	u8				ctxid_size;
-	u8				vmid_size;
-	u8				ccsize;
-	u16				ccitmin;
-	u8				s_ex_level;
-	u8				ns_ex_level;
-	u8				q_support;
-	u8				os_lock_model;
 	bool				sticky_enable : 1;
 	bool				boot_enable : 1;
 	bool				os_unlock : 1;
-	bool				instrp0 : 1;
-	bool				q_filt : 1;
-	bool				trcbb : 1;
-	bool				trccond : 1;
-	bool				retstack : 1;
-	bool				trccci : 1;
-	bool				trc_error : 1;
-	bool				syncpr : 1;
-	bool				stallctl : 1;
-	bool				sysstall : 1;
-	bool				nooverflow : 1;
-	bool				atbtrig : 1;
-	bool				lpoverride : 1;
-	bool				skip_power_up : 1;
 	bool				paused : 1;
 	u64				trfcr;
 	struct etmv4_config		config;
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 04/13] coresight: etm4x: exclude ss_status from drvdata->config
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

The purpose of TRCSSCSRn register is to show status of
the corresponding Single-shot Comparator Control and input supports.
That means writable field's purpose for reset or restore from idle status
not for configuration.

Therefore, exclude ss_status from drvdata->config and move it to drvdata.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-cfg.c |  1 -
 .../hwtracing/coresight/coresight-etm4x-core.c    | 15 +++++++--------
 .../hwtracing/coresight/coresight-etm4x-sysfs.c   | 10 +++++-----
 drivers/hwtracing/coresight/coresight-etm4x.h     |  7 ++++++-
 4 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
index c302072b293a..d14d7c8a23e5 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c
@@ -86,7 +86,6 @@ static int etm4_cfg_map_reg_offset(struct etmv4_drvdata *drvdata,
 		off_mask =  (offset & GENMASK(11, 5));
 		do {
 			CHECKREGIDX(TRCSSCCRn(0), ss_ctrl, idx, off_mask);
-			CHECKREGIDX(TRCSSCSRn(0), ss_status, idx, off_mask);
 			CHECKREGIDX(TRCSSPCICRn(0), ss_pe_cmp, idx, off_mask);
 		} while (0);
 	} else if ((offset >= TRCCIDCVRn(0)) && (offset <= TRCVMIDCVRn(7))) {
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index b2b092a76eb5..afa64a339b6e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -91,7 +91,7 @@ static bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
 	const struct etmv4_caps *caps = &drvdata->caps;
 
 	return (n < caps->nr_ss_cmp) && caps->nr_pe_cmp &&
-	       (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
+	       (drvdata->ss_status[n] & TRCSSCSRn_PC);
 }
 
 u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
@@ -573,11 +573,9 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 		etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i));
 
 	for (i = 0; i < caps->nr_ss_cmp; i++) {
-		/* always clear status bit on restart if using single-shot */
-		if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
-			config->ss_status[i] &= ~TRCSSCSRn_STATUS;
 		etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i));
-		etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i));
+		/* always clear status and pending bits on restart if using single-shot */
+		etm4x_relaxed_write32(csa, 0x0, TRCSSCSRn(i));
 		if (etm4x_sspcicrn_present(drvdata, i))
 			etm4x_relaxed_write32(csa, config->ss_pe_cmp[i], TRCSSPCICRn(i));
 	}
@@ -1057,7 +1055,7 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
 
 	/* read the status of the single shot comparators */
 	for (i = 0; i < caps->nr_ss_cmp; i++) {
-		config->ss_status[i] =
+		drvdata->ss_status[i] =
 			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
 	}
 
@@ -1503,8 +1501,9 @@ static void etm4_init_arch_data(void *info)
 	 */
 	caps->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
 	for (i = 0; i < caps->nr_ss_cmp; i++) {
-		drvdata->config.ss_status[i] =
-			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
+		drvdata->ss_status[i] = etm4x_relaxed_read32(csa, TRCSSCSRn(i));
+		drvdata->ss_status[i] &= (TRCSSCSRn_PC | TRCSSCSRn_DV |
+					  TRCSSCSRn_DA | TRCSSCSRn_INST);
 	}
 	/* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
 	caps->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 7de3c58a47b4..71e95d152ee6 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -1829,8 +1829,8 @@ static ssize_t sshot_ctrl_store(struct device *dev,
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->ss_idx;
 	config->ss_ctrl[idx] = FIELD_PREP(TRCSSCCRn_SAC_ARC_RST_MASK, val);
-	/* must clear bit 31 in related status register on programming */
-	config->ss_status[idx] &= ~TRCSSCSRn_STATUS;
+	/* must clear bit 31 and 30 in related status register on programming */
+	drvdata->ss_status[idx] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING);
 	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
@@ -1844,7 +1844,7 @@ static ssize_t sshot_status_show(struct device *dev,
 	struct etmv4_config *config = &drvdata->config;
 
 	raw_spin_lock(&drvdata->spinlock);
-	val = config->ss_status[config->ss_idx];
+	val = drvdata->ss_status[config->ss_idx];
 	raw_spin_unlock(&drvdata->spinlock);
 	return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
 }
@@ -1879,8 +1879,8 @@ static ssize_t sshot_pe_ctrl_store(struct device *dev,
 	raw_spin_lock(&drvdata->spinlock);
 	idx = config->ss_idx;
 	config->ss_pe_cmp[idx] = FIELD_PREP(TRCSSPCICRn_PC_MASK, val);
-	/* must clear bit 31 in related status register on programming */
-	config->ss_status[idx] &= ~TRCSSCSRn_STATUS;
+	/* must clear bit 31 and 30 in related status register on programming */
+	drvdata->ss_status[idx] &= ~(TRCSSCSRn_STATUS | TRCSSCSRn_PENDING);
 	raw_spin_unlock(&drvdata->spinlock);
 	return size;
 }
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 8168676f2945..dcd4ca143f83 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -213,6 +213,7 @@
 #define TRCACATRn_EXLEVEL_MASK			GENMASK(14, 8)
 
 #define TRCSSCSRn_STATUS			BIT(31)
+#define TRCSSCSRn_PENDING			BIT(30)
 #define TRCSSCCRn_SAC_ARC_RST_MASK		GENMASK(24, 0)
 
 #define TRCSSPCICRn_PC_MASK			GENMASK(7, 0)
@@ -729,6 +730,9 @@ static inline u32 etm4_res_sel_pair(u8 res_sel_idx)
 #define ETM_DEFAULT_ADDR_COMP		0
 
 #define TRCSSCSRn_PC			BIT(3)
+#define TRCSSCSRn_DV			BIT(2)
+#define TRCSSCSRn_DA			BIT(1)
+#define TRCSSCSRn_INST			BIT(0)
 
 /* PowerDown Control Register bits */
 #define TRCPDCR_PU			BIT(3)
@@ -977,7 +981,6 @@ struct etmv4_config {
 	u32				res_ctrl[ETM_MAX_RES_SEL]; /* TRCRSCTLRn */
 	u8				ss_idx;
 	u32				ss_ctrl[ETM_MAX_SS_CMP];
-	u32				ss_status[ETM_MAX_SS_CMP];
 	u32				ss_pe_cmp[ETM_MAX_SS_CMP];
 	u8				addr_idx;
 	u64				addr_val[ETM_MAX_SINGLE_ADDR_CMP];
@@ -1072,6 +1075,7 @@ struct etmv4_save_state {
  * @config:	structure holding configuration parameters.
  * @save_state:	State to be preserved across power loss
  * @paused:	Indicates if the trace unit is paused.
+ * @ss_status:	The status of the corresponding single-shot comparator.
  * @arch_features: Bitmap of arch features of etmv4 devices.
  */
 struct etmv4_drvdata {
@@ -1091,6 +1095,7 @@ struct etmv4_drvdata {
 	u64				trfcr;
 	struct etmv4_config		config;
 	struct etmv4_save_state		*save_state;
+	u32				ss_status[ETM_MAX_SS_CMP];
 	DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX);
 };
 
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 05/13] coresight: etm4x: remove redundant fields in etmv4_save_state
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

Some of fields are redundant in etmv4_save_state and never used:

    ss_status => trcsscsr
    seq_state => trcseqstr
    cntr_val => trccntvr
    vinst_ctrl => trcvictlr

Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index dcd4ca143f83..bfd5e544f68d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -1045,11 +1045,6 @@ struct etmv4_save_state {
 
 	u32	trcclaimset;
 
-	u32	cntr_val[ETMv4_MAX_CNTR];
-	u32	seq_state;
-	u32	vinst_ctrl;
-	u32	ss_status[ETM_MAX_SS_CMP];
-
 	u32	trcpdcr;
 };
 
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 02/13] coresight: etm4x: fix underflow for nrseqstate
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

TCRSEQEVR<n> is implemented only when TCRIDR5.NUMSEQSTATE is 0b100,
in which case n ranges from 0 to 2; otherwise, TCRIDR5.NUMSEQSTATE is 0b000.

Therefore, drvdata->nrseqstate should be checked before entering the loop.

Link: https://developer.arm.com/documentation/ihi0064/latest/ [0]
Fixes: 2e1cdfe184b5 ("coresight-etm4x: Adding CoreSight ETM4x driver")
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 .../hwtracing/coresight/coresight-etm4x-core.c | 18 ++++++++++--------
 .../coresight/coresight-etm4x-sysfs.c          |  2 ++
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 74b7063d130e..ba5b8b423bd4 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -544,9 +544,11 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
 	etm4x_relaxed_write32(csa, config->vissctlr, TRCVISSCTLR);
 	if (drvdata->nr_pe_cmp)
 		etm4x_relaxed_write32(csa, config->vipcssctlr, TRCVIPCSSCTLR);
-	for (i = 0; i < drvdata->nrseqstate - 1; i++)
-		etm4x_relaxed_write32(csa, config->seq_ctrl[i], TRCSEQEVRn(i));
+
 	if (drvdata->nrseqstate) {
+		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+			etm4x_relaxed_write32(csa, config->seq_ctrl[i], TRCSEQEVRn(i));
+
 		etm4x_relaxed_write32(csa, config->seq_rst, TRCSEQRSTEVR);
 		etm4x_relaxed_write32(csa, config->seq_state, TRCSEQSTR);
 	}
@@ -1927,10 +1929,10 @@ static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	if (drvdata->nr_pe_cmp)
 		state->trcvipcssctlr = etm4x_read32(csa, TRCVIPCSSCTLR);
 
-	for (i = 0; i < drvdata->nrseqstate - 1; i++)
-		state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i));
-
 	if (drvdata->nrseqstate) {
+		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+			state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i));
+
 		state->trcseqrstevr = etm4x_read32(csa, TRCSEQRSTEVR);
 		state->trcseqstr = etm4x_read32(csa, TRCSEQSTR);
 	}
@@ -2058,10 +2060,10 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 	if (drvdata->nr_pe_cmp)
 		etm4x_relaxed_write32(csa, state->trcvipcssctlr, TRCVIPCSSCTLR);
 
-	for (i = 0; i < drvdata->nrseqstate - 1; i++)
-		etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i));
-
 	if (drvdata->nrseqstate) {
+		for (i = 0; i < drvdata->nrseqstate - 1; i++)
+			etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i));
+
 		etm4x_relaxed_write32(csa, state->trcseqrstevr, TRCSEQRSTEVR);
 		etm4x_relaxed_write32(csa, state->trcseqstr, TRCSEQSTR);
 	}
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index e9eeea6240d5..0e1ad175aa1e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -1395,6 +1395,8 @@ static ssize_t seq_idx_store(struct device *dev,
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
 	struct etmv4_config *config = &drvdata->config;
 
+	if (!drvdata->nrseqstate)
+		return -ENOTSUPP;
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
 	if (val >= drvdata->nrseqstate - 1)
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 01/13] coresight: etm4x: fix wrong check of etm4x_sspcicrn_present()
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun
In-Reply-To: <20260422132203.977549-1-yeoreum.yun@arm.com>

According to Embedded Trace Macrocell Architecture Specification
ETMv4.0 to ETM4.6 [0], TRCSSPCICR<n> is present only if all of
the following are true:

  - TRCIDR4.NUMSSCC > n.
  - TRCIDR4.NUMPC > 0b0000.
  - TRCSSCSR<n>.PC == 0b1.

Comment for etm4x_sspcicrn_present() is align with the specification.
However, the check should use drvdata->nr_pe_cmp to check TRCIDR4.NUMPC
not nr_pe.

Link: https://developer.arm.com/documentation/ihi0064/latest/ [0]
Fixes: f6a18f354c58 ("coresight: etm4x: Handle access to TRCSSPCICRn")
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index d565a73f0042..74b7063d130e 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -89,7 +89,7 @@ static int etm4_probe_cpu(unsigned int cpu);
 static bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
 {
 	return (n < drvdata->nr_ss_cmp) &&
-	       drvdata->nr_pe &&
+	       drvdata->nr_pe_cmp &&
 	       (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
 }
 
-- 
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply related

* [PATCH v6 00/13] fix several inconsistencies with sysfs configuration in etmX
From: Yeoreum Yun @ 2026-04-22 13:21 UTC (permalink / raw)
  To: coresight, linux-arm-kernel, linux-kernel
  Cc: suzuki.poulose, mike.leach, james.clark, alexander.shishkin,
	leo.yan, jie.gan, Yeoreum Yun

The current ETMx configuration via sysfs can lead to the following
inconsistencies:

  - If a configuration is modified via sysfs while a perf session is
    active, the running configuration may differ between before
    a sched-out and after a subsequent sched-in.

  - If a perf session and sysfs session tries to enable concurrently,
    configuration from configfs could be corrupted (etm4).

  - There is chance to corrupt drvdata->config if perf session tries
    to enabled among handling cscfg_csdev_disable_active_config()
    in etm4_disable_sysfs() (etm4).

To resolve these inconsistencies, the configuration should be separated into:

  - active_config, which is applied configuration for the current session
  - config, which stores the settings configured via sysfs.

and apply configuration from configfs after taking a mode.

Also, This patch set includes some small fixes:
  - missing trace id release in etm4x.
  - underflow issue for nrseqstate.
  - wrong check in etm4x_sspcicrn_present().
  - missing call of cscfg_csdev_disable_active_config()

This patch based on v7.0

Patch History
=============
from v5 to v6:
  - fix missing of calling cscfg_csdev_disable_active_config()
  - add rb & fixes tags.
  - add ss_status field in etm4x_drvdata to expose STATUS and PENDING bits.
  - https://lore.kernel.org/all/20260415165528.3369607-1-yeoreum.yun@arm.com/

from v4 to v5:
  - add rb-tag.
  - fix underflow issue for nrseqstate.
  - fix wrong check in etm4_sspcicrn_present().
  - remove redundant fields on etmv4_save_state.
  - rename caps->ss_status to ss_cmp.
  - fix wrong location of etm4_release_trace_id.
  - https://lore.kernel.org/all/20260413142003.3549310-1-yeoreum.yun@arm.com/

from v3 to v4:
  - change etm_drvdata->spinlock type to raw_spin_lock_t
  - remove redundant call etmX_enable_hw() with starting_cpu() callsback.
  - fix missing trace id release.
  - add missing docs.
  - https://lore.kernel.org/all/20260412175506.412301-1-yeoreum.yun@arm.com/

from v2 to v3:
  - fix build error for etm3x.
  - fix checkpatch warning.
  - https://lore.kernel.org/all/20260410074310.2693385-1-yeoreum.yun@arm.com/

from v1 to v2
  - rebased to v7.0-rc7.
  - introduce etmX_caps structure to save etmX's capabilities.
  - remove ss_status from etmv4_config.
  - modify active_config after taking a mode (perf/sysfs).
  - https://lore.kernel.org/all/20260317181705.2456271-1-yeoreum.yun@arm.com/

Yeoreum Yun (13):
  coresight: etm4x: fix wrong check of etm4x_sspcicrn_present()
  coresight: etm4x: fix underflow for nrseqstate
  coresight: etm4x: introduce struct etm4_caps
  coresight: etm4x: exclude ss_status from drvdata->config
  coresight: etm4x: remove redundant fields in etmv4_save_state
  coresight: etm4x: fix leaked trace id
  coresight: etm4x: fix inconsistencies with sysfs configuration
  coresight: etm4x: remove redundant call etm4_enable_hw() with hotplug
  coresight: etm4x: missing cscfg_csdev_disable_active_config() in perf
    enable
  coresight: etm3x: change drvdata->spinlock type to raw_spin_lock_t
  coresight: etm3x: introduce struct etm_caps
  coresight: etm3x: fix inconsistencies with sysfs configuration
  coresight: etm3x: remove redundant call etm_enable_hw() with hotplug

 drivers/hwtracing/coresight/coresight-etm.h   |  46 ++-
 .../coresight/coresight-etm3x-core.c          | 101 ++---
 .../coresight/coresight-etm3x-sysfs.c         | 159 +++----
 .../hwtracing/coresight/coresight-etm4x-cfg.c |   3 +-
 .../coresight/coresight-etm4x-core.c          | 388 ++++++++++--------
 .../coresight/coresight-etm4x-sysfs.c         | 202 +++++----
 drivers/hwtracing/coresight/coresight-etm4x.h | 190 +++++----
 7 files changed, 606 insertions(+), 483 deletions(-)


base-commit: 028ef9c96e96197026887c0f092424679298aae8
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}



^ permalink raw reply

* Re: [PATCH RFC 1/2] arm64: vdso: Prepare for robust futex unlock support
From: Thomas Weißschuh @ 2026-04-22 13:17 UTC (permalink / raw)
  To: André Almeida
  Cc: Catalin Marinas, Will Deacon, Thomas Gleixner, Mark Rutland,
	Mathieu Desnoyers, Sebastian Andrzej Siewior, Carlos O'Donell,
	Peter Zijlstra, Florian Weimer, Rich Felker, Torvald Riegel,
	Darren Hart, Ingo Molnar, Davidlohr Bueso, Arnd Bergmann,
	Liam R . Howlett, Uros Bizjak, linux-arm-kernel, linux-kernel,
	linux-arch, kernel-dev
In-Reply-To: <e0ee43e3-725c-4b99-80b3-956d24beb1c7@t-8ch.de>

On 2026-04-22 15:02:45+0200, Thomas Weißschuh wrote:
> On 2026-04-17 11:56:10-0300, André Almeida wrote:
> > There will be a VDSO function to unlock non-contended robust futexes in
> > user space. The unlock sequence is racy vs. clearing the list_pending_op
> > pointer in the task's robust list head. To plug this race the kernel needs
> > to know the critical section window so it can clear the pointer when the
> > task is interrupted within that race window. The window is determined by
> > labels in the inline assembly.
> > 
> > Signed-off-by: André Almeida <andrealmeid@igalia.com>
> > ---
> > RFC: Those symbols can't be found by the linker after patch 2/2, it fails with:
> > 
> > ld: arch/arm64/kernel/vdso.o: in function `vdso_futex_robust_unlock_update_ips':
> > arch/arm64/kernel/vdso.c:72:(.text+0x200): undefined reference to `__futex_list64_try_unlock_cs_success'
> > ld: arch/arm64/kernel/vdso.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `__futex_list64_try_unlock_cs_success' which may bind externally can not be used when making a shared object; recompile with -fPIC
> > arch/arm64/kernel/vdso.c:72:(.text+0x200): dangerous relocation: unsupported relocation
> 
> arch/arm64/kernel/vdso.o is a kernel object.
> __futex_list64_try_unlock_cs_success is a vDSO symbol.
> They live in wholly different objects, which are never linked together.
> Look at VDSO_SYMBOL() to get the offset of the vDSO symbol in kernel code.
> 
> (...)

The diff below shows the idea. Compat code is not fixed, and I didn't
even try to run it. Also please use CONFIG_COMPAT_VDSO over plain
CONFIG_COMPAT.

diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h
index 182fde1df3dd..232b46969088 100644
--- a/arch/arm64/include/asm/vdso.h
+++ b/arch/arm64/include/asm/vdso.h
@@ -18,10 +18,6 @@
 
 extern char vdso_start[], vdso_end[];
 extern char vdso32_start[], vdso32_end[];
-extern char __futex_list64_try_unlock_cs_success[], __futex_list64_try_unlock_cs_end[];
-#ifdef CONFIG_COMPAT
-extern char __futex_list32_try_unlock_cs_success[], __futex_list32_try_unlock_cs_end[];
-#endif
 
 #endif /* !__ASSEMBLER__ */
 
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 42a82e73a774..45eb1aa627a2 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -64,21 +64,17 @@ static void vdso_futex_robust_unlock_update_ips(enum vdso_abi abi, struct mm_str
 	unsigned long vdso = (unsigned long) mm->context.vdso;
 	struct futex_mm_data *fd = &mm->futex;
 
-	/*
-	 * RFC: won't compile due to undefined reference to `__futex_list64_try_unlock_cs_...`
-
 	if (abi == VDSO_ABI_AA64) {
-		futex_set_vdso_cs_range(fd, 0, vdso, (uintptr_t) __futex_list64_try_unlock_cs_success,
-					(uintptr_t) __futex_list64_try_unlock_cs_end, false);
+		futex_set_vdso_cs_range(fd, 0, vdso, (uintptr_t)VDSO_SYMBOL(vdso, futex_list64_try_unlock_cs_success),
+					(uintptr_t)VDSO_SYMBOL(vdso, futex_list64_try_unlock_cs_end), false);
 	}
 
-#ifdef CONFIG_COMPAT
+#ifdef CONFIG_COMPAT_VDSO
 	if (abi == VDSO_ABI_AA32) {
 		futex_set_vdso_cs_range(fd, 1, vdso, (uintptr_t) __futex_list32_try_unlock_cs_success,
 					(uintptr_t) __futex_list32_try_unlock_cs_end, true);
 	}
 #endif
-	*/
 }
 #else
 static inline void vdso_futex_robust_unlock_update_ips(enum vdso_abi abi, struct mm_struct *mm) { }
diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S
index 33ce58516580..a17e6eab9d3f 100644
--- a/arch/arm64/kernel/vdso/vdso.lds.S
+++ b/arch/arm64/kernel/vdso/vdso.lds.S
@@ -116,3 +116,5 @@ VERSION
  * Make the sigreturn code visible to the kernel.
  */
 VDSO_sigtramp		= __kernel_rt_sigreturn;
+VDSO_futex_list64_try_unlock_cs_success = __futex_list64_try_unlock_cs_success;
+VDSO_futex_list64_try_unlock_cs_end = __futex_list64_try_unlock_cs_end;


^ permalink raw reply related

* Re: [PATCH RFC 2/2] clk: scmi: Add support for two #clock-cells to pass rate rounding mode
From: Sudeep Holla @ 2026-04-22 13:14 UTC (permalink / raw)
  To: Peng Fan (OSS)
  Cc: Michael Turquette, Stephen Boyd, Rob Herring, Sudeep Holla,
	Krzysztof Kozlowski, Conor Dooley, Cristian Marussi, linux-kernel,
	linux-clk, devicetree, arm-scmi, linux-arm-kernel, Peng Fan
In-Reply-To: <20260306-scmi-clk-round-v1-2-61e2a5df9051@nxp.com>

On Fri, Mar 06, 2026 at 02:20:13PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> SCMI CLOCK_RATE_SET allows the caller to specify the rounding behaviour
> when setting a clock rate. The previously added dt-bindings header
> defines three modes:
> 
>   ROUND_DOWN / ROUND_UP / ROUND_AUTO
> 
> To enable device tree clients to select a rounding mode, extend the
> SCMI clock provider to support "#clock-cells = <2>", where the second
> cell encodes the desired rounding mode. The default remains
> ROUND_DOWN for backwards compatibility with existing device trees.
> 

Where is the binding update documented ? It's not in 1/2.

Also if it can be static in the device tree, why can't it be
autonomously handled in the platform firmware ? I think I know the
answer for this but I want to make sure it is a valid use-case and
gets documented here as part of binding updates.

-- 
Regards,
Sudeep


^ permalink raw reply

* Re: [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64 and tcmalloc everywhere
From: Peter Zijlstra @ 2026-04-22 13:13 UTC (permalink / raw)
  To: Mathias Stearn
  Cc: Thomas Gleixner, Mathieu Desnoyers, Catalin Marinas, Will Deacon,
	Boqun Feng, Paul E. McKenney, Chris Kennelly, Dmitry Vyukov,
	regressions, linux-kernel, linux-arm-kernel, Ingo Molnar,
	Mark Rutland, Jinjie Ruan, Blake Oler
In-Reply-To: <20260422125647.GP3126523@noisy.programming.kicks-ass.net>

On Wed, Apr 22, 2026 at 02:56:47PM +0200, Peter Zijlstra wrote:
> On Wed, Apr 22, 2026 at 11:50:26AM +0200, Mathias Stearn wrote:
> 
> > Additionally, it breaks tcmalloc specifically by failing to overwrite
> > the cpu_id_start field at points where it was relied on for
> > correctness.
> 
> This specific behaviour was documented as being wrong and running with
> DEBUG_RSEQ would have flagged it.
> 
> The tcmalloc issue has been contentious for a long time. The tcmalloc
> folks relied on something that was documented to be wrong. It has been
> reported to the tcmalloc people many years ago and if you were to run
> tcmalloc on most any kernel (very much including 6.19) with
> DEBUG_RSEQ=y, it would have yelled.
> 
> The tcmalloc people didn't care. There was a proposal for an RSEQ
> extension for what they need, and they didn't care. All this should be
> in their bugzilla or whatever.
> 
> The RSEQ rework improved performance significantly for everyone, and
> kept all the documented behaviour (+- arm64 bug). Tcmalloc got screwed
> over because they relied on implementation behaviour that was
> specifically documented to be broken. And they didn't care. Google was
> very much aware of this. And hasn't lifted a finger to remedy it.

Also: https://lore.kernel.org/all/874io5andc.ffs@tglx/ 


^ permalink raw reply

* Re: [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64 and tcmalloc everywhere
From: Mark Rutland @ 2026-04-22 13:09 UTC (permalink / raw)
  To: Mathias Stearn
  Cc: Thomas Gleixner, Mathieu Desnoyers, Catalin Marinas, Will Deacon,
	Boqun Feng, Paul E. McKenney, Chris Kennelly, Dmitry Vyukov,
	regressions, linux-kernel, linux-arm-kernel, Peter Zijlstra,
	Ingo Molnar, Jinjie Ruan, Blake Oler
In-Reply-To: <CAHnCjA25b+nO2n5CeifknSKHssJpPrjnf+dtr7UgzRw4Zgu=oA@mail.gmail.com>

Hi Mathias,

On Wed, Apr 22, 2026 at 11:50:26AM +0200, Mathias Stearn wrote:
> TL;DR: As of 6.19, rseq no longer provides the documented atomicity
> guarantees on arm64 by failing to abort the critical section on same-core
> preemption/resumption. Additionally, it breaks tcmalloc specifically by
> failing to overwrite the cpu_id_start field at points where it was relied
> on for correctness.

Thanks for the report, and the test case.

As a holding reply, I'm looking into this now from the arm64 side.

I'll leave it to Thomas/Peter/Mathieu to comment w.r.t. the issue you
raise with cpu_id_start.

For some reason, this mail didn't make it to my inbox, and I had to grab
it from lore using b4. That might be a problem with my local mail
server; I'm just noting that in case others also didn't receive this.

Mark.

> This is a SEVERE breakage for MongoDB. We received several user reports of
> crashes on 6.19. I made a stress test that showed that 6.19 can cause
> malloc to return the same pointer twice without it being freed. Because
> that can cause arbitrary corruption, our latest releases have all been
> patched to refuse to start at all on 6.19+.
> 
> TCMalloc uses rseq in a "creative" way described at
> https://github.com/google/tcmalloc/blob/master/docs/rseq.md. In particular,
> the "Current CPU Slabs Pointer Caching" section describes an optimization
> that relies on an undocumented fact that the kernel was always overwriting
> cpu_id_start (even when it wouldn't change) to invalidate a user-space
> cache. Since the change to stop writing cpu_id_start seemed to be
> intentional as part of a refactoring merged in 2b09f480f0a1, I started
> working on a userspace patch to stop relying on that. Unfortunately when
> that was complete I ran into a wall that is impossible to work around from
> userspace.
> 
> On arm64, the kernel no longer meets the documented guarantee that rseq
> critical sections are atomic with respect to preemption. It seems to only
> abort the critical section when the thread is migrated to a different core.
> The attached test proves it and passes on x86 both before and after 6.19,
> and on arm before 6.19, but fails on arm with 6.19. It pins the process to
> a single core and then has an rseq critical section that observes a change
> made by another thread which is supposed to be impossible. I think this
> will break basically any real usage of rseq, other than just reading the
> current cpu_id.
> 
> An LLM pointed to these two specific commits in the refactor as causing
> this (oldest first):
> - 39a167560a61 rseq: Optimize event setting
> This assumed that user_irq would be set on preemption but it wasn't on
> arm64, so TIF_NOTIFY_RESUME isn't raised on same cpu preemption.
> - 566d8015f7ee rseq: Avoid CPU/MM CID updates when no event pending
> This broke TCMalloc slab caching trick by not overwriting cpu_id_start on
> every return to userspace
> 
> (I have a lot more analysis and suggested fixes from LLMs since I used them
> heavily in this testing and analysis, but I won't spam you with the slop
> unless requested)
> 
> The arm64 change is a clear breakage and I'm sure it will be
> uncontroversial to fix. I can imagine more resistance to reverting to the
> old behavior of always overwriting the cpu_id_start field since that seems
> to have been an intentional optimization choice. I have reached out to the
> TCMalloc maintainers (CC'd) and believe there is a solution that gets the
> vast majority of the optimization while still preserving the behavior that
> TCMalloc currently relies on[1].
> 
> Any time a critical section might be aborted (migration, preemption, signal
> delivery, and membarrier IPI), the kernel already must (but doesn't on
> arm64 at the moment) check the rseq_cs field to see if the thread is in a
> critical section, and is documented as nulling the pointer after (I assume
> to make later checks cheaper). It would be sufficient for tcmalloc's
> internal usage if every time the kernel nulled out rseq_cs, it also wrote
> the cpu id to cpu_id_start. That should be essentially free since you are
> already writing to the same cache line. It was pointed out that that could
> be an issue if another rseq user in the same thread nulled rseq_cs after
> its critical section, which would require the kernel to update cpu_id_start
> each time it checks rseq_cs, regardless of whether it nulls it. We aren't
> aware of any processes that mix tcmalloc with other rseq usages that null
> out the field from userspace, but we can't rule them out since it is open
> source. Either way, this preserves the property of not updating
> cpu_id_start on every syscall return and non-membarrier interrupts, which I
> assume is where the majority of the optimization win was from.
> 
> All testing of problematic versions was performed on x86_64 and
> aarch64 Ubuntu 24.04.4 with the kernel manually upgraded to
> 6.19.8-061908-generic. Source analysis was performed on the v6.19 tag. I
> had a few AI agents confirm that nothing in the relevant changes to master
> should have solved this, but I have not yet tested there.
> 
> $ cat /proc/version
> Linux version 6.19.8-061908-generic (kernel@balboa)
> (aarch64-linux-gnu-gcc-15 (Ubuntu 15.2.0-15ubuntu1) 15.2.0, GNU ld (GNU
> Binutils for Ubuntu) 2.46) #202603131837 SMP PREEMPT_DYNAMIC Sat Mar 14
> 00:00:07 UTC 2026
> 
> [1]  There is also an exploration of some options to make tcmalloc not rely
> on the cpu_id_start overwriting. However we would strongly prefer that
> existing binaries continue to work on 6.19 kernels, even if newer binaries
> don't need that. At least for a good while.



^ permalink raw reply

* Re: [PATCH RFC 1/2] arm64: vdso: Prepare for robust futex unlock support
From: Thomas Weißschuh @ 2026-04-22 13:02 UTC (permalink / raw)
  To: André Almeida
  Cc: Catalin Marinas, Will Deacon, Thomas Gleixner, Mark Rutland,
	Mathieu Desnoyers, Sebastian Andrzej Siewior, Carlos O'Donell,
	Peter Zijlstra, Florian Weimer, Rich Felker, Torvald Riegel,
	Darren Hart, Ingo Molnar, Davidlohr Bueso, Arnd Bergmann,
	Liam R . Howlett, Uros Bizjak, linux-arm-kernel, linux-kernel,
	linux-arch, kernel-dev
In-Reply-To: <20260417-tonyk-robust_arm-v1-1-03aa64e2ff1a@igalia.com>

On 2026-04-17 11:56:10-0300, André Almeida wrote:
> There will be a VDSO function to unlock non-contended robust futexes in
> user space. The unlock sequence is racy vs. clearing the list_pending_op
> pointer in the task's robust list head. To plug this race the kernel needs
> to know the critical section window so it can clear the pointer when the
> task is interrupted within that race window. The window is determined by
> labels in the inline assembly.
> 
> Signed-off-by: André Almeida <andrealmeid@igalia.com>
> ---
> RFC: Those symbols can't be found by the linker after patch 2/2, it fails with:
> 
> ld: arch/arm64/kernel/vdso.o: in function `vdso_futex_robust_unlock_update_ips':
> arch/arm64/kernel/vdso.c:72:(.text+0x200): undefined reference to `__futex_list64_try_unlock_cs_success'
> ld: arch/arm64/kernel/vdso.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `__futex_list64_try_unlock_cs_success' which may bind externally can not be used when making a shared object; recompile with -fPIC
> arch/arm64/kernel/vdso.c:72:(.text+0x200): dangerous relocation: unsupported relocation

arch/arm64/kernel/vdso.o is a kernel object.
__futex_list64_try_unlock_cs_success is a vDSO symbol.
They live in wholly different objects, which are never linked together.
Look at VDSO_SYMBOL() to get the offset of the vDSO symbol in kernel code.

(...)


Thomas


^ permalink raw reply

* Re: [REGRESSION] rseq: refactoring in v6.19 broke everyone on arm64 and tcmalloc everywhere
From: Peter Zijlstra @ 2026-04-22 12:56 UTC (permalink / raw)
  To: Mathias Stearn
  Cc: Thomas Gleixner, Mathieu Desnoyers, Catalin Marinas, Will Deacon,
	Boqun Feng, Paul E. McKenney, Chris Kennelly, Dmitry Vyukov,
	regressions, linux-kernel, linux-arm-kernel, Ingo Molnar,
	Mark Rutland, Jinjie Ruan, Blake Oler
In-Reply-To: <CAHnCjA25b+nO2n5CeifknSKHssJpPrjnf+dtr7UgzRw4Zgu=oA@mail.gmail.com>

On Wed, Apr 22, 2026 at 11:50:26AM +0200, Mathias Stearn wrote:

> Additionally, it breaks tcmalloc specifically by failing to overwrite
> the cpu_id_start field at points where it was relied on for
> correctness.

This specific behaviour was documented as being wrong and running with
DEBUG_RSEQ would have flagged it.

The tcmalloc issue has been contentious for a long time. The tcmalloc
folks relied on something that was documented to be wrong. It has been
reported to the tcmalloc people many years ago and if you were to run
tcmalloc on most any kernel (very much including 6.19) with
DEBUG_RSEQ=y, it would have yelled.

The tcmalloc people didn't care. There was a proposal for an RSEQ
extension for what they need, and they didn't care. All this should be
in their bugzilla or whatever.

The RSEQ rework improved performance significantly for everyone, and
kept all the documented behaviour (+- arm64 bug). Tcmalloc got screwed
over because they relied on implementation behaviour that was
specifically documented to be broken. And they didn't care. Google was
very much aware of this. And hasn't lifted a finger to remedy it.




^ permalink raw reply

* Re: [PATCH RFC 1/2] arm64: vdso: Prepare for robust futex unlock support
From: Florian Weimer @ 2026-04-22 12:56 UTC (permalink / raw)
  To: André Almeida
  Cc: Catalin Marinas, Will Deacon, Thomas Gleixner, Mark Rutland,
	Mathieu Desnoyers, Sebastian Andrzej Siewior, Carlos O'Donell,
	Peter Zijlstra, Rich Felker, Torvald Riegel, Darren Hart,
	Ingo Molnar, Davidlohr Bueso, Arnd Bergmann, Liam R . Howlett,
	Uros Bizjak, Thomas Weißschuh, linux-arm-kernel,
	linux-kernel, linux-arch, kernel-dev
In-Reply-To: <32642d18-8c83-47ad-8456-1813084c4622@igalia.com>

* André Almeida:

> Hi Florian,
>
> Em 17/04/2026 12:08, Florian Weimer escreveu:
>> * André Almeida:
>> 
>>> There will be a VDSO function to unlock non-contended robust futexes in
>>> user space. The unlock sequence is racy vs. clearing the list_pending_op
>>> pointer in the task's robust list head. To plug this race the kernel needs
>>> to know the critical section window so it can clear the pointer when the
>>> task is interrupted within that race window. The window is determined by
>>> labels in the inline assembly.
>>>
>>> Signed-off-by: André Almeida <andrealmeid@igalia.com>
>>> ---
>>> RFC: Those symbols can't be found by the linker after patch 2/2, it fails with:
>>>
>>> ld: arch/arm64/kernel/vdso.o: in function `vdso_futex_robust_unlock_update_ips':
>>> arch/arm64/kernel/vdso.c:72:(.text+0x200): undefined reference to `__futex_list64_try_unlock_cs_success'
>>> ld: arch/arm64/kernel/vdso.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `__futex_list64_try_unlock_cs_success' which may bind externally can not be used when making a shared object; recompile with -fPIC
>>> arch/arm64/kernel/vdso.c:72:(.text+0x200): dangerous relocation: unsupported relocation
>> I think your GLOBLS definition adds a 64 suffix.  That shouldn't be
>> necessary on AArch64.  It's not reflected in the references, so you end
>> up with an undefined symbol error.
>> 
>
> Why aarch64 doesn't need the 64 suffix? objdump shows that the final
> label name is __futex_list64_try_unlock_cs_success, which should match
> what the linker is trying to find, AFAIC.

Sorry, I was confused about how this is expected to work.

Florian



^ permalink raw reply

* [PATCH] crypto: testmgr - disallow RSA PKCS#1 SHA-1 sig algs in FIPS mode
From: jeffbarnes @ 2026-04-22 12:49 UTC (permalink / raw)
  To: Herbert Xu, David S. Miller, Maxime Coquelin, Alexandre Torgue
  Cc: linux-crypto, linux-stm32, linux-arm-kernel, linux-kernel,
	Jeff Barnes, Jeff Barnes

From: Jeff Barnes <jeffbarnes@microsoft.com>

When booted with fips=1, RSA signature generation using SHA-1 must not be
available.  However, pkcs1pad(rsa,sha1) can currently be instantiated
because it is not present in alg_test_descs; alg_test() falls through the
no_test path and succeeds, after which the algorithm appears in /proc/crypto
as fips-capable. 【1-ebd9df】

Add explicit alg_test_descs entries for pkcs1pad(rsa,sha1) and pkcs1(rsa,sha1)
without marking them fips_allowed, so they are treated as not FIPS-allowed
when fips=1 is enabled.

Include both names to cover kernels where RSA sign/verify is provided via
the pkcs1(...) signature template, while pkcs1pad(...) remains for the
traditional wrapper naming and/or RSAES operations. 【2-17cc14】

Signed-off-by: Jeff Barnes <jeffbarnes@linux.microsoft.com>
---
This series fixes an issue where SHA-1 RSA signature generation remains
available when booted with fips=1.

On a FIPS-enabled system, pkcs1pad(rsa,sha1) can be instantiated even
though SHA-1 must not be available for signature generation. The reason
is that the algorithm is not listed in crypto/testmgr.c's alg_test_descs,
so alg_test() falls through the no_test path and succeeds. Once
instantiated, /proc/crypto reports the algorithm as "fips: yes".

This patch adds explicit alg_test_descs entries for:

  - pkcs1pad(rsa,sha1)
  - pkcs1(rsa,sha1)

without setting fips=1, so they are treated as not FIPS-allowed in
FIPS mode.

Both names are covered to handle kernels where RSA signature operations
are provided via the pkcs1(...) signature template, while pkcs1pad(...)
remains for the historical wrapper naming and/or RSAES operations.

Reproducer / evidence (current behavior):
  1) Boot with fips=1 (confirm /proc/sys/crypto/fips_enabled == 1)
  2) Allocate the transform:
       crypto_alloc_akcipher("pkcs1pad(rsa,sha1)", 0, 0)
  3) Observe that /proc/crypto now contains:
       name   : pkcs1pad(rsa,sha1)
       fips   : yes
       selftest: passed
  4) A simple in-kernel demo module can instantiate the transform and reach
     the signing path in FIPS mode.

With this change, attempts to instantiate these SHA-1 RSA signing
templates in FIPS mode are rejected, preventing SHA-1 signature
generation in approved mode.

Thanks for taking a look.

Signed-off-by: Jeff Barnes <jeffbarnes@microsoft.com>
---
 crypto/testmgr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 30671e7bc349..e54d298a26c1 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -5306,6 +5306,9 @@ static const struct alg_test_desc alg_test_descs[] = {
 		.suite = {
 			.sig = __VECS(pkcs1_rsa_none_tv_template)
 		}
+	}, {
+		.alg = "pkcs1(rsa,sha1)",
+		.test = alg_test_null,
 	}, {
 		.alg = "pkcs1(rsa,sha224)",
 		.test = alg_test_null,
@@ -5341,6 +5344,9 @@ static const struct alg_test_desc alg_test_descs[] = {
 		.alg = "pkcs1pad(rsa)",
 		.test = alg_test_null,
 		.fips_allowed = 1,
+	}, {
+		.alg = "pkcs1pad(rsa,sha1)",
+		.test = alg_test_null,
 	}, {
 		.alg = "rfc3686(ctr(aes))",
 		.generic_driver = "rfc3686(ctr(aes-lib))",

---
base-commit: 8879a3c110cb8ca5a69c937643f226697aa551d9
change-id: 20260422-disallow_rsa_sha1_signing_in_fips_mode-8fbb6229ad54

Best regards,
-- 
Jeff Barnes <jeffbarnes@microsoft.com>



^ permalink raw reply related

* Re: [PATCH] net/stmmac: Fix typos: 'tx_undeflow_irq' -> 'tx_underflow_irq'
From: Andrew Lunn @ 2026-04-22 12:47 UTC (permalink / raw)
  To: Jakub Raczynski
  Cc: netdev, linux-kernel, kuba, davem, andrew+netdev, kernel-janitors,
	linux-arm-kernel, linux-stm32
In-Reply-To: <aeiJ3zr4WJAm1UCk@AMDC4622.eu.corp.samsungelectronics.net>

> I don't see anything wrong with it?
> - naming is correct, same as stmmac_extra_stats from common.h, as it
>   wouldn't compile otherwise
> - string length is ok, as max name length is ETH_GSTRING_LEN=32 and it is
>   not close
> - ethtool just polls data from driver and in my tests it is ok
> - all instances of 'undeflow' are changed
> - 'underflow' semantic is ok, 'undeflow' is just not correct
> 
> Please correct me if I am wrong, but imo no issues with this patch.

ABI

This name is published as part of the kAPI. You are changing its
name. User space could be looking for this name, even thought it has a
typo in it.

     Andrew


^ permalink raw reply

* Re: [PATCH RFC 1/2] arm64: vdso: Prepare for robust futex unlock support
From: André Almeida @ 2026-04-22 12:46 UTC (permalink / raw)
  To: Florian Weimer
  Cc: Catalin Marinas, Will Deacon, Thomas Gleixner, Mark Rutland,
	Mathieu Desnoyers, Sebastian Andrzej Siewior, Carlos O'Donell,
	Peter Zijlstra, Rich Felker, Torvald Riegel, Darren Hart,
	Ingo Molnar, Davidlohr Bueso, Arnd Bergmann, Liam R . Howlett,
	Uros Bizjak, Thomas Weißschuh, linux-arm-kernel,
	linux-kernel, linux-arch, kernel-dev
In-Reply-To: <lhu1pgd8w0f.fsf@oldenburg.str.redhat.com>

Hi Florian,

Em 17/04/2026 12:08, Florian Weimer escreveu:
> * André Almeida:
> 
>> There will be a VDSO function to unlock non-contended robust futexes in
>> user space. The unlock sequence is racy vs. clearing the list_pending_op
>> pointer in the task's robust list head. To plug this race the kernel needs
>> to know the critical section window so it can clear the pointer when the
>> task is interrupted within that race window. The window is determined by
>> labels in the inline assembly.
>>
>> Signed-off-by: André Almeida <andrealmeid@igalia.com>
>> ---
>> RFC: Those symbols can't be found by the linker after patch 2/2, it fails with:
>>
>> ld: arch/arm64/kernel/vdso.o: in function `vdso_futex_robust_unlock_update_ips':
>> arch/arm64/kernel/vdso.c:72:(.text+0x200): undefined reference to `__futex_list64_try_unlock_cs_success'
>> ld: arch/arm64/kernel/vdso.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `__futex_list64_try_unlock_cs_success' which may bind externally can not be used when making a shared object; recompile with -fPIC
>> arch/arm64/kernel/vdso.c:72:(.text+0x200): dangerous relocation: unsupported relocation
> 
> I think your GLOBLS definition adds a 64 suffix.  That shouldn't be
> necessary on AArch64.  It's not reflected in the references, so you end
> up with an undefined symbol error.
> 

Why aarch64 doesn't need the 64 suffix? objdump shows that the final 
label name is __futex_list64_try_unlock_cs_success, which should match 
what the linker is trying to find, AFAIC.

	André


^ permalink raw reply

* Re: [PATCH 0/3] arm64/virt: Add Arm CCA measurement register support
From: Jason Gunthorpe @ 2026-04-22 12:40 UTC (permalink / raw)
  To: Sami Mujawar
  Cc: Suzuki Poulose, Dan Williams,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Catalin Marinas, will@kernel.org,
	thuth@redhat.com, Steven Price, gshan@redhat.com, Yeoreum Yun,
	cedric.xing@intel.com, Dan Williams, Dionna Glaze,
	Aneesh Kumar K . V, Alexey Kardashevskiy,
	linux-coco@lists.linux.dev
In-Reply-To: <AS8PR08MB680669CBFA9654BC12179D5E842F2@AS8PR08MB6806.eurprd08.prod.outlook.com>

On Wed, Apr 22, 2026 at 08:57:00AM +0000, Sami Mujawar wrote:

> > So this is tying it to the same FW event log that TPM uses.
> > 
> > I think that strengthens my point this should all be uninform. TPM
> > drivers are directly exposing the event log today, but I guess that
> > needs generalization if non-TPM drivers are going to present it as
> > well.
> > 
> > How do you imagine getting and manipulating the EFI event log to use
> > with this?
>
> The event logs from UEFI will be handed off to the OS using CCEL
> ACPI table. The CCEL table spec update can be seen at
> https://github.com/tianocore/edk2/issues/11384

I ment from linux userspace. event log is well establihsed in the aCPI
side for TPM and in Linux today it is only exposed to userspace
through TPM.

This is not TPM, so how do you intend to give the event log to
userspace?

Jason


^ permalink raw reply

* Re: [PATCH] KVM: arm64: Validate the FF-A memory access descriptor placement
From: Marc Zyngier @ 2026-04-22 12:24 UTC (permalink / raw)
  To: Sebastian Ene
  Cc: oupton, will, ayrton, catalin.marinas, joey.gouly, korneld,
	kvmarm, linux-arm-kernel, linux-kernel, android-kvm,
	mrigendra.chaubey, perlarsen, suzuki.poulose, yuzenghui, stable
In-Reply-To: <20260422102540.1433704-1-sebastianene@google.com>

On Wed, 22 Apr 2026 11:25:40 +0100,
Sebastian Ene <sebastianene@google.com> wrote:
> 
> Prevent the pKVM hypervisor from making assumptions that the
> endpoint memory access descriptor (EMAD) comes right after the
> FF-A memory region header and enforce a strict placement for it
> when validating an FF-A memory lend/share transaction.

As I read this, you want to remove a bad assumption...

> 
> Prior to FF-A version 1.1 the header of the memory region
> didn't contain an offset to the endpoint memory access descriptor.
> The layout of a memory transaction looks like this:
> 
>   Field name				| Offset
> 					 -- 0
> [ Header (ffa_mem_region)               |__ ep_mem_offset
>   EMAD 1 (ffa_mem_region_attributes)	|
> ]
> 
> Reject the host from specifying a memory access descriptor offset
> that is different than the size of the memory region header.

And yet you decide that you want to enforce this assumption. I don't
understand how you arrive to this conclusion.

Looking at the spec, it appears that the offset is *designed* to allow
a gap between the header and the EMAD. Refusing to handle a it seems to be a
violation of the spec.

What am I missing?

	M.

-- 
Without deviation from the norm, progress is not possible.


^ permalink raw reply

* Re: [PATCH 1/4] arm64: signal: Preserve POR_EL0 if poe_context is missing
From: Will Deacon @ 2026-04-22 12:19 UTC (permalink / raw)
  To: Kevin Brodsky
  Cc: linux-arm-kernel, linux-kernel, Catalin Marinas, Joey Gouly,
	Mark Brown, Shuah Khan, linux-kselftest
In-Reply-To: <20260421144252.1440365-2-kevin.brodsky@arm.com>

Hey Kevin,

On Tue, Apr 21, 2026 at 03:42:49PM +0100, Kevin Brodsky wrote:
> Commit 2e8a1acea859 ("arm64: signal: Improve POR_EL0 handling to
> avoid uaccess failures") delayed the write to POR_EL0 in
> rt_sigreturn to avoid spurious uaccess failures. This change however
> relies on the poe_context frame record being present: on a system
> supporting POE, calling sigreturn without a poe_context record now
> results in writing arbitrary data from the kernel stack into POR_EL0.
> 
> Fix this by adding a valid_fields member to struct
> user_access_state, and zeroing the struct on allocation.
> restore_poe_context() then indicates that the por_el0 field is valid
> by setting the corresponding bit in valid_fields, and
> restore_user_access_state() only touches POR_EL0 if there is a valid
> value to set it to. This is in line with how POR_EL0 was originally
> handled; all frame records are currently optional, except
> fpsimd_context.
> 
> restore_user_access_state() is also called if setting up the signal
> frame fails, so we also initialise valid_fields in that case. For
> consistency, setup_sigframe() now also checks valid_fields to decide
> whether to write a poe_context record, avoiding another call to
> system_supports_poe().
> 
> Fixes: 2e8a1acea859 ("arm64: signal: Improve POR_EL0 handling to avoid uaccess failures")
> Reported-by: Will Deacon <will@kernel.org>
> Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>

Thanks for fixing this. I think your patch is correct, but I have a
couple of comments inline. Please let me know what you think.

> ---
>  arch/arm64/kernel/signal.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
> index 08ffc5a5aea4..3f17aed5b4f0 100644
> --- a/arch/arm64/kernel/signal.c
> +++ b/arch/arm64/kernel/signal.c
> @@ -67,6 +67,8 @@ struct rt_sigframe_user_layout {
>  	unsigned long end_offset;
>  };
>  
> +#define UA_STATE_HAS_POR_EL0	BIT(0)
> +
>  /*
>   * Holds any EL0-controlled state that influences unprivileged memory accesses.
>   * This includes both accesses done in userspace and uaccess done in the kernel.
> @@ -74,8 +76,12 @@ struct rt_sigframe_user_layout {
>   * This state needs to be carefully managed to ensure that it doesn't cause
>   * uaccess to fail when setting up the signal frame, and the signal handler
>   * itself also expects a well-defined state when entered.
> + *
> + * The valid_fields member is a bitfield (see UA_STATE_HAS_*), specifying which
> + * of the remaining fields is valid (has been set to a value).
>   */
>  struct user_access_state {
> +	unsigned int valid_fields;
>  	u64 por_el0;
>  };

Do you think it would be worth adding some accessors to make it easier
to keep the flags in sync? For example:

/* Stores por_el0 into uas->por_el0 and sets UA_STATE_HAS_POR_EL0 */
void set_ua_state_por_el0(struct user_access_state *uas, u64 por_el0);

/*
 * If UA_STATE_HAS_POR_EL0, *por_el0 = uas->por_el0 and return 0.
 * Otherwise, return -ENOENT.
 */
int get_ua_state_por_el0(struct user_access_state *uas, u64 *por_el0);

WDYT?

> @@ -1095,7 +1104,7 @@ SYSCALL_DEFINE0(rt_sigreturn)
>  {
>  	struct pt_regs *regs = current_pt_regs();
>  	struct rt_sigframe __user *frame;
> -	struct user_access_state ua_state;
> +	struct user_access_state ua_state = {0};

nit: {} should do (no need for the '0'). Same in setup_rt_frame().

Will


^ permalink raw reply

* [PATCH] pinctrl: meson: amlogic-a4: fix deadlock issue
From: Xianwei Zhao via B4 Relay @ 2026-04-22 11:44 UTC (permalink / raw)
  To: Linus Walleij, Neil Armstrong, Kevin Hilman, Jerome Brunet,
	Martin Blumenstingl
  Cc: linux-amlogic, linux-gpio, linux-arm-kernel, linux-kernel,
	Xianwei Zhao

From: Xianwei Zhao <xianwei.zhao@amlogic.com>

Accessing the pinconf-pins sysfs node may deadlock.

pinconf_pins_show() holds pctldev->mutex, and the platform driver
calls pinctrl_find_gpio_range_from_pin(), which tries to acquire
the same mutex again, leading to a deadlock.

Use pinctrl_find_gpio_range_from_pin_nolock() to fix this issue.

Fixes: 6e9be3abb78c ("pinctrl: Add driver support for Amlogic SoCs")
Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
Fix deadlock issue.
---
 drivers/pinctrl/meson/pinctrl-amlogic-a4.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
index e2293a872dcb..35d27626a336 100644
--- a/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
+++ b/drivers/pinctrl/meson/pinctrl-amlogic-a4.c
@@ -292,7 +292,7 @@ static int aml_calc_reg_and_bit(struct pinctrl_gpio_range *range,
 static int aml_pinconf_get_pull(struct aml_pinctrl *info, unsigned int pin)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit, val;
 	int ret, conf;
@@ -326,7 +326,7 @@ static int aml_pinconf_get_drive_strength(struct aml_pinctrl *info,
 					  u16 *drive_strength_ua)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit;
 	unsigned int val;
@@ -365,7 +365,7 @@ static int aml_pinconf_get_gpio_bit(struct aml_pinctrl *info,
 				    unsigned int reg_type)
 {
 	struct pinctrl_gpio_range *range =
-			 pinctrl_find_gpio_range_from_pin(info->pctl, pin);
+			 pinctrl_find_gpio_range_from_pin_nolock(info->pctl, pin);
 	struct aml_gpio_bank *bank = gpio_chip_to_bank(range->gc);
 	unsigned int reg, bit, val;
 	int ret;

---
base-commit: bd7fd288490c64835a74c05e631c102ce056d5e1
change-id: 20260422-fix-pinconf-42be1cc2f5af

Best regards,
-- 
Xianwei Zhao <xianwei.zhao@amlogic.com>




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