1 files changed, 14 insertions, 7 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index dcd4049e92fc..3a9c7d81afbf 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3220,17 +3220,22 @@ static int perf_event_index(struct perf_event *event)
 }
 
 static void calc_timer_values(struct perf_event *event,
+                                u64 *now,
                                 u64 *enabled,
                                 u64 *running)
 {
-        u64 now, ctx_time;
+        u64 ctx_time;
 
-        now = perf_clock();
-        ctx_time = event->shadow_ctx_time + now;
+        *now = perf_clock();
+        ctx_time = event->shadow_ctx_time + *now;
         *enabled = ctx_time - event->tstamp_enabled;
         *running = ctx_time - event->tstamp_running;
 }
 
+void __weak perf_update_user_clock(struct perf_event_mmap_page *userpg, u64 now)
+{
+}
+
 /*
  * Callers need to ensure there can be no nesting of this function, otherwise
  * the seqlock logic goes bad. We can not serialize this because the arch
@@ -3240,7 +3245,7 @@ void perf_event_update_userpage(struct perf_event *event)
 {
         struct perf_event_mmap_page *userpg;
         struct ring_buffer *rb;
-        u64 enabled, running;
+        u64 enabled, running, now;
 
         rcu_read_lock();
         /*
@@ -3252,7 +3257,7 @@ void perf_event_update_userpage(struct perf_event *event)
          * because of locking issue as we can be called in
          * NMI context
          */
-        calc_timer_values(event, &enabled, &running);
+        calc_timer_values(event, &now, &enabled, &running);
         rb = rcu_dereference(event->rb);
         if (!rb)
                 goto unlock;
@@ -3277,6 +3282,8 @@ void perf_event_update_userpage(struct perf_event *event)
         userpg->time_running = running +
                         atomic64_read(&event->child_total_time_running);
 
+        perf_update_user_clock(userpg, now);
+
         barrier();
         ++userpg->lock;
         preempt_enable();
@@ -3763,7 +3770,7 @@ static void perf_output_read_group(struct perf_output_handle *handle,
 static void perf_output_read(struct perf_output_handle *handle,
                              struct perf_event *event)
 {
-        u64 enabled = 0, running = 0;
+        u64 enabled = 0, running = 0, now;
         u64 read_format = event->attr.read_format;
 
         /*
@@ -3776,7 +3783,7 @@ static void perf_output_read(struct perf_output_handle *handle,
          * NMI context
          */
         if (read_format & PERF_FORMAT_TOTAL_TIMES)
-                calc_timer_values(event, &enabled, &running);
+                calc_timer_values(event, &now, &enabled, &running);
 
         if (event->attr.read_format & PERF_FORMAT_GROUP)
                 perf_output_read_group(handle, event, enabled, running);