1 files changed, 66 insertions, 2 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 6f8cd7da1a01..c8e375440403 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -452,6 +452,8 @@ enum perf_callchain_context {
 #include <linux/fs.h>
 #include <linux/pid_namespace.h>
 #include <linux/workqueue.h>
+#include <linux/ftrace.h>
+#include <linux/cpu.h>
 #include <asm/atomic.h>
 
 #define PERF_MAX_STACK_DEPTH            255
@@ -840,11 +842,56 @@ extern atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
 
 extern void __perf_sw_event(u32, u64, int, struct pt_regs *, u64);
 
+extern void
+perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int skip);
+
+/*
+ * Take a snapshot of the regs. Skip ip and frame pointer to
+ * the nth caller. We only need a few of the regs:
+ * - ip for PERF_SAMPLE_IP
+ * - cs for user_mode() tests
+ * - bp for callchains
+ * - eflags, for future purposes, just in case
+ */
+static inline void perf_fetch_caller_regs(struct pt_regs *regs, int skip)
+{
+        unsigned long ip;
+
+        memset(regs, 0, sizeof(*regs));
+
+        switch (skip) {
+        case 1 :
+                ip = CALLER_ADDR0;
+                break;
+        case 2 :
+                ip = CALLER_ADDR1;
+                break;
+        case 3 :
+                ip = CALLER_ADDR2;
+                break;
+        case 4:
+                ip = CALLER_ADDR3;
+                break;
+        /* No need to support further for now */
+        default:
+                ip = 0;
+        }
+
+        return perf_arch_fetch_caller_regs(regs, ip, skip);
+}
+
 static inline void
 perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
 {
-        if (atomic_read(&perf_swevent_enabled[event_id]))
+        if (atomic_read(&perf_swevent_enabled[event_id])) {
+                struct pt_regs hot_regs;
+
+                if (!regs) {
+                        perf_fetch_caller_regs(&hot_regs, 1);
+                        regs = &hot_regs;
+                }
                 __perf_sw_event(event_id, nr, nmi, regs, addr);
+        }
 }
 
 extern void __perf_event_mmap(struct vm_area_struct *vma);
@@ -880,7 +927,8 @@ static inline bool perf_paranoid_kernel(void)
 }
 
 extern void perf_event_init(void);
-extern void perf_tp_event(int event_id, u64 addr, u64 count, void *record, int entry_size);
+extern void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
+                          int entry_size, struct pt_regs *regs);
 extern void perf_bp_event(struct perf_event *event, void *data);
 
 #ifndef perf_misc_flags
@@ -936,5 +984,21 @@ static inline void perf_event_disable(struct perf_event *event)		{ }
 #define perf_output_put(handle, x) \
         perf_output_copy((handle), &(x), sizeof(x))
 
+/*
+ * This has to have a higher priority than migration_notifier in sched.c.
+ */
+#define perf_cpu_notifier(fn)                                   \
+do {                                                            \
+        static struct notifier_block fn##_nb __cpuinitdata =    \
+                { .notifier_call = fn, .priority = 20 };        \
+        fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE,             \
+                (void *)(unsigned long)smp_processor_id());     \
+        fn(&fn##_nb, (unsigned long)CPU_STARTING,               \
+                (void *)(unsigned long)smp_processor_id());     \
+        fn(&fn##_nb, (unsigned long)CPU_ONLINE,                 \
+                (void *)(unsigned long)smp_processor_id());     \
+        register_cpu_notifier(&fn##_nb);                        \
+} while (0)
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_PERF_EVENT_H */