5 files changed, 109 insertions, 2 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 412b790f5da6..92a056f6d18d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -859,6 +859,9 @@ struct perf_event {
 #ifdef CONFIG_EVENT_TRACING
         struct ftrace_event_call        *tp_event;
         struct event_filter             *filter;
+#ifdef CONFIG_FUNCTION_TRACER
+        struct ftrace_ops               ftrace_ops;
+#endif
 #endif
 
 #ifdef CONFIG_CGROUP_PERF
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 638476af8d7b..76a1c5094bbf 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -595,6 +595,8 @@ static inline int ftrace_trace_task(struct task_struct *task)
 static inline int ftrace_is_dead(void) { return 0; }
 #endif
 
+int ftrace_event_is_function(struct ftrace_event_call *call);
+
 /*
  * struct trace_parser - servers for reading the user input separated by spaces
  * @cont: set if the input is not complete - no final space char was found
@@ -832,4 +834,13 @@ extern const char *__stop___trace_bprintk_fmt[];
         FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 #include "trace_entries.h"
 
+#ifdef CONFIG_PERF_EVENTS
+#ifdef CONFIG_FUNCTION_TRACER
+int perf_ftrace_event_register(struct ftrace_event_call *call,
+                               enum trace_reg type, void *data);
+#else
+#define perf_ftrace_event_register NULL
+#endif /* CONFIG_FUNCTION_TRACER */
+#endif /* CONFIG_PERF_EVENTS */
+
 #endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index 93365907f219..47db7eda0531 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -55,7 +55,7 @@
 /*
  * Function trace entry - function address and parent function address:
  */
-FTRACE_ENTRY(function, ftrace_entry,
+FTRACE_ENTRY_REG(function, ftrace_entry,
 
         TRACE_FN,
 
@@ -64,7 +64,9 @@ FTRACE_ENTRY(function, ftrace_entry,
                 __field(        unsigned long,  parent_ip       )
         ),
 
-        F_printk(" %lx <-- %lx", __entry->ip, __entry->parent_ip)
+        F_printk(" %lx <-- %lx", __entry->ip, __entry->parent_ip),
+
+        perf_ftrace_event_register
 );
 
 /* Function call entry */
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index d72af0b03822..fdeeb5c49627 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -24,6 +24,11 @@ static int	total_ref_count;
 static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
                                  struct perf_event *p_event)
 {
+        /* The ftrace function trace is allowed only for root. */
+        if (ftrace_event_is_function(tp_event) &&
+            perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
         /* No tracing, just counting, so no obvious leak */
         if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
                 return 0;
@@ -250,3 +255,84 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
         return raw_data;
 }
 EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);
+
+#ifdef CONFIG_FUNCTION_TRACER
+static void
+perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip)
+{
+        struct ftrace_entry *entry;
+        struct hlist_head *head;
+        struct pt_regs regs;
+        int rctx;
+
+#define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
+                    sizeof(u64)) - sizeof(u32))
+
+        BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE);
+
+        perf_fetch_caller_regs(&regs);
+
+        entry = perf_trace_buf_prepare(ENTRY_SIZE, TRACE_FN, NULL, &rctx);
+        if (!entry)
+                return;
+
+        entry->ip = ip;
+        entry->parent_ip = parent_ip;
+
+        head = this_cpu_ptr(event_function.perf_events);
+        perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0,
+                              1, &regs, head);
+
+#undef ENTRY_SIZE
+}
+
+static int perf_ftrace_function_register(struct perf_event *event)
+{
+        struct ftrace_ops *ops = &event->ftrace_ops;
+
+        ops->flags |= FTRACE_OPS_FL_CONTROL;
+        ops->func = perf_ftrace_function_call;
+        return register_ftrace_function(ops);
+}
+
+static int perf_ftrace_function_unregister(struct perf_event *event)
+{
+        struct ftrace_ops *ops = &event->ftrace_ops;
+        return unregister_ftrace_function(ops);
+}
+
+static void perf_ftrace_function_enable(struct perf_event *event)
+{
+        ftrace_function_local_enable(&event->ftrace_ops);
+}
+
+static void perf_ftrace_function_disable(struct perf_event *event)
+{
+        ftrace_function_local_disable(&event->ftrace_ops);
+}
+
+int perf_ftrace_event_register(struct ftrace_event_call *call,
+                               enum trace_reg type, void *data)
+{
+        switch (type) {
+        case TRACE_REG_REGISTER:
+        case TRACE_REG_UNREGISTER:
+                break;
+        case TRACE_REG_PERF_REGISTER:
+        case TRACE_REG_PERF_UNREGISTER:
+                return 0;
+        case TRACE_REG_PERF_OPEN:
+                return perf_ftrace_function_register(data);
+        case TRACE_REG_PERF_CLOSE:
+                return perf_ftrace_function_unregister(data);
+        case TRACE_REG_PERF_ADD:
+                perf_ftrace_function_enable(data);
+                return 0;
+        case TRACE_REG_PERF_DEL:
+                perf_ftrace_function_disable(data);
+                return 0;
+        }
+
+        return -EINVAL;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index f74de861cde9..a3dbee6d04cd 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -184,4 +184,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call;
         FTRACE_ENTRY_REG(call, struct_name, etype,                      \
                          PARAMS(tstruct), PARAMS(print), NULL)
 
+int ftrace_event_is_function(struct ftrace_event_call *call)
+{
+        return call == &event_function;
+}
+
 #include "trace_entries.h"