coresight: Emit sink ID in the HW_ID packets

For Perf to be able to decode when per-sink trace IDs are used, emit the
sink that's being written to for each ETM.

Perf currently errors out if it sees a newer packet version so instead
of bumping it, add a new minor version field. This can be used to
signify new versions that have backwards compatible fields. Considering
this change is only for high core count machines, it doesn't make sense
to make a breaking change for everyone.

Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20240722101202.26915-17-james.clark@linaro.org

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index faf560ba8d64975998d7b4e39122a559f85eb4b2..c427e9344a84c9fa41ae22003f015c62205c08c8 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -487,23 +487,25 @@ struct coresight_device *coresight_get_sink(struct list_head *path)
        return csdev;
 }
 
+u32 coresight_get_sink_id(struct coresight_device *csdev)
+{
+       if (!csdev->ea)
+               return 0;
+
+       /*
+        * See function etm_perf_add_symlink_sink() to know where
+        * this comes from.
+        */
+       return (u32) (unsigned long) csdev->ea->var;
+}
+
 static int coresight_sink_by_id(struct device *dev, const void *data)
 {
        struct coresight_device *csdev = to_coresight_device(dev);
-       unsigned long hash;
 
        if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
-            csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
-
-               if (!csdev->ea)
-                       return 0;
-               /*
-                * See function etm_perf_add_symlink_sink() to know where
-                * this comes from.
-                */
-               hash = (unsigned long)csdev->ea->var;
-
-               if ((u32)hash == *(u32 *)data)
+           csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
+               if (coresight_get_sink_id(csdev) == *(u32 *)data)
                        return 1;
        }
 

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 70c99f0409b2e451d143c2383782040fb5f0fe01..ad6a8f4b70b6fc37d9340bcdd4e0569a38fe1c36 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -460,6 +460,7 @@ static void etm_event_start(struct perf_event *event, int flags)
        struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
        struct list_head *path;
        u64 hw_id;
+       u8 trace_id;
 
        if (!csdev)
                goto fail;
@@ -512,11 +513,16 @@ static void etm_event_start(struct perf_event *event, int flags)
         */
        if (!cpumask_test_cpu(cpu, &event_data->aux_hwid_done)) {
                cpumask_set_cpu(cpu, &event_data->aux_hwid_done);
-               hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK,
-                                  CS_AUX_HW_ID_CURR_VERSION);
-               hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK,
-                                   coresight_trace_id_read_cpu_id_map(cpu,
-                                                                      &sink->perf_sink_id_map));
+
+               trace_id = coresight_trace_id_read_cpu_id_map(cpu, &sink->perf_sink_id_map);
+
+               hw_id = FIELD_PREP(CS_AUX_HW_ID_MAJOR_VERSION_MASK,
+                               CS_AUX_HW_ID_MAJOR_VERSION);
+               hw_id |= FIELD_PREP(CS_AUX_HW_ID_MINOR_VERSION_MASK,
+                               CS_AUX_HW_ID_MINOR_VERSION);
+               hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, trace_id);
+               hw_id |= FIELD_PREP(CS_AUX_HW_ID_SINK_ID_MASK, coresight_get_sink_id(sink));
+
                perf_report_aux_output_id(event, hw_id);
        }
 

diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index 61a46d3bdcc85af3d76781180e32c810ccf53d91..05f891ca6b5c9d71bdf36585328f7cfd292b3d36 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -148,6 +148,7 @@ int coresight_make_links(struct coresight_device *orig,
                         struct coresight_device *target);
 void coresight_remove_links(struct coresight_device *orig,
                            struct coresight_connection *conn);
+u32 coresight_get_sink_id(struct coresight_device *csdev);
 
 #if IS_ENABLED(CONFIG_CORESIGHT_SOURCE_ETM3X)
 extern int etm_readl_cp14(u32 off, unsigned int *val);

diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 51ac441a37c3e38ff325896199bd3af3ff79438a..89b0ac0014b0dfe16dc435ae5834859c82025adb 100644 (file)
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -49,12 +49,21 @@
  * Interpretation of the PERF_RECORD_AUX_OUTPUT_HW_ID payload.
  * Used to associate a CPU with the CoreSight Trace ID.
  * [07:00] - Trace ID - uses 8 bits to make value easy to read in file.
- * [59:08] - Unused (SBZ)
- * [63:60] - Version
+ * [39:08] - Sink ID - as reported in /sys/bus/event_source/devices/cs_etm/sinks/
+ *           Added in minor version 1.
+ * [55:40] - Unused (SBZ)
+ * [59:56] - Minor Version - previously existing fields are compatible with
+ *           all minor versions.
+ * [63:60] - Major Version - previously existing fields mean different things
+ *           in new major versions.
  */
 #define CS_AUX_HW_ID_TRACE_ID_MASK     GENMASK_ULL(7, 0)
-#define CS_AUX_HW_ID_VERSION_MASK      GENMASK_ULL(63, 60)
+#define CS_AUX_HW_ID_SINK_ID_MASK      GENMASK_ULL(39, 8)
 
-#define CS_AUX_HW_ID_CURR_VERSION 0
+#define CS_AUX_HW_ID_MINOR_VERSION_MASK        GENMASK_ULL(59, 56)
+#define CS_AUX_HW_ID_MAJOR_VERSION_MASK        GENMASK_ULL(63, 60)
+
+#define CS_AUX_HW_ID_MAJOR_VERSION 0
+#define CS_AUX_HW_ID_MINOR_VERSION 1
 
 #endif