4.19-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt (VMware) rostedt@goodmis.org
commit f1f5b14afd7cce39e6a9b25c685e1ea34c231096 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 ARM 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: Russell King linux@armlinux.org.uk Cc: linux-arm-kernel@lists.infradead.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/arm/kernel/ftrace.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-)
--- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -227,9 +227,7 @@ void prepare_ftrace_return(unsigned long unsigned long frame_pointer) { unsigned long return_hooker = (unsigned long) &return_to_handler; - struct ftrace_graph_ent trace; unsigned long old; - int err;
if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; @@ -237,21 +235,8 @@ void prepare_ftrace_return(unsigned long old = *parent; *parent = return_hooker;
- trace.func = self_addr; - trace.depth = current->curr_ret_stack + 1; - - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { + if (function_graph_enter(old, self_addr, frame_pointer, NULL)) *parent = old; - return; - } - - err = ftrace_push_return_trace(old, self_addr, &trace.depth, - frame_pointer, NULL); - if (err == -EBUSY) { - *parent = old; - return; - } }
#ifdef CONFIG_DYNAMIC_FTRACE