2 files changed, 22 insertions, 8 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 0bebb5c348b8..d36f68b08acc 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -595,7 +595,7 @@ extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
                                      char *filter_str);
 extern void ftrace_profile_free_filter(struct perf_event *event);
 extern void *perf_trace_buf_prepare(int size, unsigned short type,
-                                    struct pt_regs *regs, int *rctxp);
+                                    struct pt_regs **regs, int *rctxp);
 
 static inline void
 perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 664de5a4ec46..216653466a67 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -659,6 +659,7 @@ static inline int is_software_event(struct perf_event *event)
 
 extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
 
+extern void ___perf_sw_event(u32, u64, struct pt_regs *, u64);
 extern void __perf_sw_event(u32, u64, struct pt_regs *, u64);
 
 #ifndef perf_arch_fetch_caller_regs
@@ -683,14 +684,25 @@ static inline void perf_fetch_caller_regs(struct pt_regs *regs)
 static __always_inline void
 perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
 {
-        struct pt_regs hot_regs;
+        if (static_key_false(&perf_swevent_enabled[event_id]))
+                __perf_sw_event(event_id, nr, regs, addr);
+}
+
+DECLARE_PER_CPU(struct pt_regs, __perf_regs[4]);
 
+/*
+ * 'Special' version for the scheduler, it hard assumes no recursion,
+ * which is guaranteed by us not actually scheduling inside other swevents
+ * because those disable preemption.
+ */
+static __always_inline void
+perf_sw_event_sched(u32 event_id, u64 nr, u64 addr)
+{
         if (static_key_false(&perf_swevent_enabled[event_id])) {
-                if (!regs) {
-                        perf_fetch_caller_regs(&hot_regs);
-                        regs = &hot_regs;
-                }
-                __perf_sw_event(event_id, nr, regs, addr);
+                struct pt_regs *regs = this_cpu_ptr(&__perf_regs[0]);
+
+                perf_fetch_caller_regs(regs);
+                ___perf_sw_event(event_id, nr, regs, addr);
         }
 }
 
@@ -706,7 +718,7 @@ static inline void perf_event_task_sched_in(struct task_struct *prev,
 static inline void perf_event_task_sched_out(struct task_struct *prev,
                                              struct task_struct *next)
 {
-        perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, NULL, 0);
+        perf_sw_event_sched(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 0);
 
         if (static_key_false(&perf_sched_events.key))
                 __perf_event_task_sched_out(prev, next);
@@ -817,6 +829,8 @@ static inline int perf_event_refresh(struct perf_event *event, int refresh)
 static inline void
 perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)     { }
 static inline void
+perf_sw_event_sched(u32 event_id, u64 nr, u64 addr)                     { }
+static inline void
 perf_bp_event(struct perf_event *event, void *data)                     { }
 
 static inline int perf_register_guest_info_callbacks