function_graph: Move ftrace_graph_ret_addr() to fgraph.c
Move the function function_graph_ret_addr() to fgraph.c, as the management
of the curr_ret_stack is going to change, and all the accesses to ret_stack
needs to be done in fgraph.c.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index cc35606..90fcefc 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -232,6 +232,61 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
return ret;
}
+/**
+ * ftrace_graph_ret_addr - convert a potentially modified stack return address
+ * to its original value
+ *
+ * This function can be called by stack unwinding code to convert a found stack
+ * return address ('ret') to its original value, in case the function graph
+ * tracer has modified it to be 'return_to_handler'. If the address hasn't
+ * been modified, the unchanged value of 'ret' is returned.
+ *
+ * 'idx' is a state variable which should be initialized by the caller to zero
+ * before the first call.
+ *
+ * 'retp' is a pointer to the return address on the stack. It's ignored if
+ * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
+ */
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+ unsigned long ret, unsigned long *retp)
+{
+ int index = task->curr_ret_stack;
+ int i;
+
+ if (ret != (unsigned long)return_to_handler)
+ return ret;
+
+ if (index < 0)
+ return ret;
+
+ for (i = 0; i <= index; i++)
+ if (task->ret_stack[i].retp == retp)
+ return task->ret_stack[i].ret;
+
+ return ret;
+}
+#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+ unsigned long ret, unsigned long *retp)
+{
+ int task_idx;
+
+ if (ret != (unsigned long)return_to_handler)
+ return ret;
+
+ task_idx = task->curr_ret_stack;
+
+ if (!task->ret_stack || task_idx < *idx)
+ return ret;
+
+ task_idx -= *idx;
+ (*idx)++;
+
+ return task->ret_stack[task_idx].ret;
+}
+#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+
static struct ftrace_ops graph_ops = {
.func = ftrace_stub,
.flags = FTRACE_OPS_FL_RECURSION_SAFE |