FAILED: patch "[PATCH] riscv/function_graph: Simplify with function_graph_enter()" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-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@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e949b6db51dc172a35c962bc4414ca148315fe21 Mon Sep 17 00:00:00 2001

From: "Steven Rostedt (VMware)" rostedt@goodmis.org Date: Sun, 18 Nov 2018 17:31:44 -0500 Subject: [PATCH] riscv/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 riscv 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: Greentime Hu greentime@andestech.com Cc: Alan Kao alankao@andestech.com Cc: stable@kernel.org Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback") Reviewed-by: Palmer Dabbelt palmer@sifive.com Reviewed-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 1157b6b52d25..c433f6d3dd64 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -132,7 +132,6 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, { unsigned long return_hooker = (unsigned long)&return_to_handler; unsigned long old; - struct ftrace_graph_ent trace; int err;

if (unlikely(atomic_read(&current->tracing_graph_pause))) @@ -144,17 +143,8 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, */ old = *parent;

- trace.func = self_addr; - trace.depth = current->curr_ret_stack + 1; - - if (!ftrace_graph_entry(&trace)) - return; - - err = ftrace_push_return_trace(old, self_addr, &trace.depth, - frame_pointer, parent); - if (err == -EBUSY) - return; - *parent = return_hooker; + if (function_graph_enter(old, self_addr, frame_pointer, parent)) + *parent = return_hooker; }

#ifdef CONFIG_DYNAMIC_FTRACE