[PATCH 4.19 109/139] arm64: function_graph: Simplify with function_graph_enter()
From: Greg Kroah-Hartman
Date: Tue Dec 04 2018 - 05:59:41 EST
4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
commit 01e0ab2c4ff12358f15a856fd1a7bbea0670972b upstream.
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 arm64 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: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxx
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/kernel/ftrace.c | 15 +--------------
1 file changed, 1 insertion(+), 14 deletions(-)
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -216,8 +216,6 @@ void prepare_ftrace_return(unsigned long
{
unsigned long return_hooker = (unsigned long)&return_to_handler;
unsigned long old;
- struct ftrace_graph_ent trace;
- int err;
if (unlikely(atomic_read(¤t->tracing_graph_pause)))
return;
@@ -229,18 +227,7 @@ void prepare_ftrace_return(unsigned long
*/
old = *parent;
- trace.func = self_addr;
- trace.depth = current->curr_ret_stack + 1;
-
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace))
- return;
-
- err = ftrace_push_return_trace(old, self_addr, &trace.depth,
- frame_pointer, NULL);
- if (err == -EBUSY)
- return;
- else
+ if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
*parent = return_hooker;
}