Patch "powerpc/function_graph: Simplify with function_graph_enter()" has been added to the 4.19-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    powerpc/function_graph: Simplify with function_graph_enter()

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-function_graph-simplify-with-function_graph_enter.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From fe60522ec60082a1dd735691b82c64f65d4ad15e Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Date: Sun, 18 Nov 2018 17:28:53 -0500
Subject: powerpc/function_graph: Simplify with function_graph_enter()

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

commit fe60522ec60082a1dd735691b82c64f65d4ad15e 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 powerpc 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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kernel/trace/ftrace.c |   15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -697,7 +697,6 @@ int ftrace_disable_ftrace_graph_caller(v
  */
 unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
 {
-	struct ftrace_graph_ent trace;
 	unsigned long return_hooker;
 
 	if (unlikely(ftrace_graph_is_dead()))
@@ -708,18 +707,8 @@ unsigned long prepare_ftrace_return(unsi
 
 	return_hooker = ppc_function_entry(return_to_handler);
 
-	trace.func = ip;
-	trace.depth = current->curr_ret_stack + 1;
-
-	/* Only trace if the calling function expects to */
-	if (!ftrace_graph_entry(&trace))
-		goto out;
-
-	if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
-				     NULL) == -EBUSY)
-		goto out;
-
-	parent = return_hooker;
+	if (!function_graph_enter(parent, ip, 0, NULL))
+		parent = return_hooker;
 out:
 	return parent;
 }


Patches currently in stable-queue which might be from rostedt@goodmis.org are

queue-4.19/function_graph-create-function_graph_enter-to-consolidate-architecture-code.patch
queue-4.19/sh-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/function_graph-move-return-callback-before-update-of-curr_ret_stack.patch
queue-4.19/nds32-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/function_graph-use-new-curr_ret_depth-to-manage-depth-instead-of-curr_ret_stack.patch
queue-4.19/sparc-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/parisc-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/x86-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/powerpc-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/function_graph-reverse-the-order-of-pushing-the-ret_stack-and-the-callback.patch
queue-4.19/arm-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/mips-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/function_graph-make-ftrace_push_return_trace-static.patch
queue-4.19/arm64-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/riscv-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/s390-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/microblaze-function_graph-simplify-with-function_graph_enter.patch
queue-4.19/function_graph-have-profiler-use-curr_ret_stack-and-not-depth.patch