microblaze: function_graph: Simplify with function_graph_enter()

The function_graph_enter() function does the work of calling the function
graph hook function and the management of the shadow stack, simplifying the
work done in the architecture dependent prepare_ftrace_return().

Have microblaze use the new code, and remove the shadow stack management as well as
having to set up the trace structure.

This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.

Cc: Michal Simek <monstr@monstr.eu>
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index d57563c58a26be43672098d9895d9107c945e8d8..224eea40e1ee805fa15d56f33e16b248fbaec30a 100644 (file)
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -22,8 +22,7 @@
 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 {
        unsigned long old;
-       int faulted, err;
-       struct ftrace_graph_ent trace;
+       int faulted;
        unsigned long return_hooker = (unsigned long)
                                &return_to_handler;
 
@@ -63,18 +62,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
                return;
        }
 
-       err = ftrace_push_return_trace(old, self_addr, &trace.depth, 0, NULL);
-       if (err == -EBUSY) {
+       if (function_graph_enter(old, self_addr, 0, NULL))
                *parent = old;
-               return;
-       }
-
-       trace.func = self_addr;
-       /* Only trace if the calling function expects to */
-       if (!ftrace_graph_entry(&trace)) {
-               current->curr_ret_stack--;
-               *parent = old;
-       }
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */