The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 556763e5a500d71879d632867b75826551acd49c Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Date: Sun, 18 Nov 2018 17:23:30 -0500
Subject: [PATCH] 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@xxxxxxxxx>
Cc: stable@xxxxxxxxxx
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index d57563c58a26..224eea40e1ee 100644
--- 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 */
