coresight: perf: traceid: Add perf ID allocation and notifiers

Adds in calls to allocate and release Trace ID for the CPUs in use
by the perf session.

Adds in notifier calls to the trace ID allocator that perf
events are starting and stopping.

This ensures that Trace IDs associated with CPUs remain the same
throughout the perf session, and are only released when all perf
sessions are complete.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230116124928.5440-4-mike.leach@linaro.org

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 43bbd5dc3d3b1f6840841ca942ebeb63ec84dd73..bdb9ab86173a4d0a39a57d455de7b60ff124c985 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -22,6 +22,7 @@
 #include "coresight-etm-perf.h"
 #include "coresight-priv.h"
 #include "coresight-syscfg.h"
+#include "coresight-trace-id.h"
 
 static struct pmu etm_pmu;
 static bool etm_perf_up;
@@ -228,8 +229,12 @@ static void free_event_data(struct work_struct *work)
                if (!(IS_ERR_OR_NULL(*ppath)))
                        coresight_release_path(*ppath);
                *ppath = NULL;
+               coresight_trace_id_put_cpu_id(cpu);
        }
 
+       /* mark perf event as done for trace id allocator */
+       coresight_trace_id_perf_stop();
+
        free_percpu(event_data->path);
        kfree(event_data);
 }
@@ -300,6 +305,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 {
        u32 id, cfg_hash;
        int cpu = event->cpu;
+       int trace_id;
        cpumask_t *mask;
        struct coresight_device *sink = NULL;
        struct coresight_device *user_sink = NULL, *last_sink = NULL;
@@ -316,6 +322,9 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
                sink = user_sink = coresight_get_sink_by_id(id);
        }
 
+       /* tell the trace ID allocator that a perf event is starting up */
+       coresight_trace_id_perf_start();
+
        /* check if user wants a coresight configuration selected */
        cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
        if (cfg_hash) {
@@ -388,6 +397,13 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
                        continue;
                }
 
+               /* ensure we can allocate a trace ID for this CPU */
+               trace_id = coresight_trace_id_get_cpu_id(cpu);
+               if (!IS_VALID_CS_TRACE_ID(trace_id)) {
+                       cpumask_clear_cpu(cpu, mask);
+                       continue;
+               }
+
                *etm_event_cpu_path_ptr(event_data, cpu) = path;
        }