1 files changed, 9 insertions, 2 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4b50357914fb..a6a9ec4cd8f5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3348,7 +3348,7 @@ static void calc_timer_values(struct perf_event *event,
         *running = ctx_time - event->tstamp_running;
 }
 
-void __weak perf_update_user_clock(struct perf_event_mmap_page *userpg, u64 now)
+void __weak arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now)
 {
 }
 
@@ -3398,7 +3398,7 @@ 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);
+        arch_perf_update_userpage(userpg, now);
 
         barrier();
         ++userpg->lock;
@@ -7116,6 +7116,13 @@ void __init perf_event_init(void)
 
         /* do not patch jump label more than once per second */
         jump_label_rate_limit(&perf_sched_events, HZ);
+
+        /*
+         * Build time assertion that we keep the data_head at the intended
+         * location.  IOW, validation we got the __reserved[] size right.
+         */
+        BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
+                     != 1024);
 }
 
 static int __init perf_event_sysfs_init(void)