[PATCH v3 14/20] coresight: tmc-etr: Introduce the notion of process ID to ETR devices

[Mathieu Poirier]

In preparation to support CPU-wide trace scenarios, introduce the notion
of process ID to ETR devices.  That way events monitoring the same process
can use the same etr_buf, allowing multiple CPUs to use the same sink.

Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c 
b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index ac1efdfc0d07..e1774d4bb5f3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -9,6 +9,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/iommu.h>
 #include <linux/slab.h>
+#include <linux/types.h>
 #include <linux/vmalloc.h>
 #include "coresight-catu.h"
 #include "coresight-etm-perf.h"
@@ -25,6 +26,7 @@ struct etr_flat_buf {
 /*
  * etr_perf_buffer - Perf buffer used for ETR
  * @etr_buf            - Actual buffer used by the ETR
+ * @pid                        - The PID this etr_perf_buffer belongs to.
  * @snaphost           - Perf session mode
  * @head               - handle->head at the beginning of the session.
  * @nr_pages           - Number of pages in the ring buffer.
@@ -32,6 +34,7 @@ struct etr_flat_buf {
  */
 struct etr_perf_buffer {
        struct etr_buf          *etr_buf;
+       pid_t                   pid;
        bool                    snapshot;
        unsigned long           head;
        int                     nr_pages;
@@ -1276,6 +1279,7 @@ static void *tmc_alloc_etr_buffer(struct coresight_device 
*csdev,
                return NULL;
        }
 
+       etr_perf->pid = task_pid_nr(event->owner);
        etr_perf->snapshot = snapshot;
        etr_perf->nr_pages = nr_pages;
        etr_perf->pages = pages;
-- 
2.17.1