[PATCH v2 18/23] coresight: trbe: Keep the perf handle in per-CPU data

[Leo Yan <leo.yan@arm.com>]

Arm SPE owns a per-CPU perf output handle for the PMU lifetime. TRBE
instead receives a handle from CoreSight when enabling its sink.

Store that session handle in trbe_cpudata instead of a separate per-CPU
pointer array, and pass the CPU data as the per-CPU IRQ context. Use this
context directly for overflow and spurious interrupt handling so local
hardware control does not depend on the current AUX buffer configuration.

Allocate the CPU data before registering the IRQ and free it after
releasing the IRQ, keeping the IRQ context valid throughout registration.

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 44 ++++++++++++----------------
 1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 9a469c8009ce8a8a8b804c2b63a68e741f1dceaa..2328aab0a084a0ac123e950f846f404d120ec2c0 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -139,6 +139,7 @@ struct trbe_save_state {
  * @cpu			- CPU this TRBE belongs to.
  * @mode		- Mode of current operation. (perf/disabled)
  * @buf			- Buffer configuration retained for the enabled session.
+ * @handle		- Perf output handle from successful enable until disable.
  * @drvdata		- TRBE specific drvdata
  * @errata		- Bit map for the errata on this TRBE.
  */
@@ -149,6 +150,7 @@ struct trbe_cpudata {
 	int cpu;
 	enum cs_mode mode;
 	struct trbe_buf *buf;
+	struct perf_output_handle *handle;
 	struct trbe_drvdata *drvdata;
 	struct trbe_save_state save_state;
 	DECLARE_BITMAP(errata, TRBE_ERRATA_MAX);
@@ -156,7 +158,6 @@ struct trbe_cpudata {
 
 struct trbe_drvdata {
 	struct trbe_cpudata __percpu *cpudata;
-	struct perf_output_handle * __percpu *handle;
 	struct hlist_node hotplug_node;
 	int irq;
 	cpumask_t supported_cpus;
@@ -1091,7 +1092,7 @@ static int arm_trbe_enable(struct coresight_device *csdev, enum cs_mode mode,
 		return ret;
 	}
 
-	*this_cpu_ptr(drvdata->handle) = handle;
+	cpudata->handle = handle;
 	cpudata->buf = buf;
 	cpudata->mode = mode;
 	return 0;
@@ -1112,16 +1113,15 @@ static int arm_trbe_disable(struct coresight_device *csdev)
 	trbe_drain_and_disable_local(cpudata);
 	clr_trbe_status();
 
-	*this_cpu_ptr(drvdata->handle) = NULL;
 	buf->cpudata = NULL;
+	cpudata->handle = NULL;
 	cpudata->buf = NULL;
 	cpudata->mode = CS_MODE_DISABLED;
 	return 0;
 }
 
-static void trbe_handle_spurious(struct perf_output_handle *handle)
+static void trbe_handle_spurious(struct trbe_cpudata *cpudata)
 {
-	struct trbe_buf *buf = etm_perf_sink_config(handle);
 	u64 trblimitr = read_sysreg_s(SYS_TRBLIMITR_EL1);
 
 	/*
@@ -1129,11 +1129,12 @@ static void trbe_handle_spurious(struct perf_output_handle *handle)
 	 * back without modifying the buffer parameters to
 	 * retain the trace collected so far.
 	 */
-	set_trbe_enabled(buf->cpudata, trblimitr);
+	set_trbe_enabled(cpudata, trblimitr);
 }
 
-static int trbe_handle_overflow(struct perf_output_handle *handle)
+static int trbe_handle_overflow(struct trbe_cpudata *cpudata)
 {
+	struct perf_output_handle *handle = cpudata->handle;
 	struct perf_event *event = handle->event;
 	struct trbe_buf *buf = etm_perf_sink_config(handle);
 	unsigned long size;
@@ -1203,9 +1204,8 @@ static u64 cpu_prohibit_trace(void)
 
 static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 {
-	struct perf_output_handle **handle_ptr = dev;
-	struct perf_output_handle *handle = *handle_ptr;
-	struct trbe_buf *buf;
+	struct trbe_cpudata *cpudata = dev;
+	struct perf_output_handle *handle = cpudata->handle;
 	enum trbe_fault_action act;
 	u64 status;
 	bool truncated = false;
@@ -1232,18 +1232,17 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 	 * Ensure the trace is visible to the CPUs and
 	 * any external aborts have been resolved.
 	 */
-	buf = etm_perf_sink_config(handle);
-	trbe_drain_and_disable_local(buf->cpudata);
+	trbe_drain_and_disable_local(cpudata);
 	clr_trbe_irq();
 	isb();
 
 	act = trbe_get_fault_act(handle, status);
 	switch (act) {
 	case TRBE_FAULT_ACT_WRAP:
-		truncated = !!trbe_handle_overflow(handle);
+		truncated = !!trbe_handle_overflow(cpudata);
 		break;
 	case TRBE_FAULT_ACT_SPURIOUS:
-		trbe_handle_spurious(handle);
+		trbe_handle_spurious(cpudata);
 		break;
 	case TRBE_FAULT_ACT_FATAL:
 		trbe_truncate_event(handle);
@@ -1507,10 +1506,6 @@ static int arm_trbe_probe_coresight(struct trbe_drvdata *drvdata)
 {
 	int cpu;
 
-	drvdata->cpudata = alloc_percpu(typeof(*drvdata->cpudata));
-	if (!drvdata->cpudata)
-		return -ENOMEM;
-
 	for_each_cpu(cpu, &drvdata->supported_cpus) {
 		/* If we fail to probe the CPU, let us defer it to hotplug callbacks */
 		if (smp_call_function_single(cpu, arm_trbe_probe_cpu, drvdata, 1))
@@ -1531,7 +1526,6 @@ static int arm_trbe_remove_coresight(struct trbe_drvdata *drvdata)
 		smp_call_function_single(cpu, arm_trbe_disable_cpu, drvdata, 1);
 		arm_trbe_remove_coresight_cpu(drvdata, cpu);
 	}
-	free_percpu(drvdata->cpudata);
 	return 0;
 }
 
@@ -1618,14 +1612,14 @@ static int arm_trbe_probe_irq(struct platform_device *pdev,
 
 	cpumask_copy(&drvdata->supported_cpus, affinity);
 
-	drvdata->handle = alloc_percpu(struct perf_output_handle *);
-	if (!drvdata->handle)
+	drvdata->cpudata = alloc_percpu(typeof(*drvdata->cpudata));
+	if (!drvdata->cpudata)
 		return -ENOMEM;
 
 	ret = request_percpu_irq_affinity(drvdata->irq, arm_trbe_irq_handler, DRVNAME,
-					  affinity, drvdata->handle);
+					  affinity, drvdata->cpudata);
 	if (ret) {
-		free_percpu(drvdata->handle);
+		free_percpu(drvdata->cpudata);
 		return ret;
 	}
 	return 0;
@@ -1633,8 +1627,8 @@ static int arm_trbe_probe_irq(struct platform_device *pdev,
 
 static void arm_trbe_remove_irq(struct trbe_drvdata *drvdata)
 {
-	free_percpu_irq(drvdata->irq, drvdata->handle);
-	free_percpu(drvdata->handle);
+	free_percpu_irq(drvdata->irq, drvdata->cpudata);
+	free_percpu(drvdata->cpudata);
 }
 
 static int arm_trbe_device_probe(struct platform_device *pdev)

-- 
2.34.1