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-rw-r--r--kernel/trace/trace_functions_graph.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 930c08e5b38..dce71a5b51b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -42,6 +42,81 @@ static struct tracer_flags tracer_flags = {
/* pid on the last trace processed */
static pid_t last_pid[NR_CPUS] = { [0 ... NR_CPUS-1] = -1 };
+/* Add a function return address to the trace stack on thread info.*/
+int
+ftrace_push_return_trace(unsigned long ret, unsigned long long time,
+ unsigned long func, int *depth)
+{
+ int index;
+
+ if (!current->ret_stack)
+ return -EBUSY;
+
+ /* The return trace stack is full */
+ if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+ atomic_inc(&current->trace_overrun);
+ return -EBUSY;
+ }
+
+ index = ++current->curr_ret_stack;
+ barrier();
+ current->ret_stack[index].ret = ret;
+ current->ret_stack[index].func = func;
+ current->ret_stack[index].calltime = time;
+ *depth = index;
+
+ return 0;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
+{
+ int index;
+
+ index = current->curr_ret_stack;
+
+ if (unlikely(index < 0)) {
+ ftrace_graph_stop();
+ WARN_ON(1);
+ /* Might as well panic, otherwise we have no where to go */
+ *ret = (unsigned long)panic;
+ return;
+ }
+
+ *ret = current->ret_stack[index].ret;
+ trace->func = current->ret_stack[index].func;
+ trace->calltime = current->ret_stack[index].calltime;
+ trace->overrun = atomic_read(&current->trace_overrun);
+ trace->depth = index;
+ barrier();
+ current->curr_ret_stack--;
+
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(void)
+{
+ struct ftrace_graph_ret trace;
+ unsigned long ret;
+
+ ftrace_pop_return_trace(&trace, &ret);
+ trace.rettime = cpu_clock(raw_smp_processor_id());
+ ftrace_graph_return(&trace);
+
+ if (unlikely(!ret)) {
+ ftrace_graph_stop();
+ WARN_ON(1);
+ /* Might as well panic. What else to do? */
+ ret = (unsigned long)panic;
+ }
+
+ return ret;
+}
+
static int graph_trace_init(struct trace_array *tr)
{
int cpu, ret;