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 07f7175b43827640d1e69c9eded89aa089a234b4 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 x86 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: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: Borislav Petkov bp@alien8.de Cc: "H. Peter Anvin" hpa@zytor.com Cc: x86@kernel.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/x86/kernel/ftrace.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-)
--- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -994,7 +994,6 @@ void prepare_ftrace_return(unsigned long { unsigned long old; int faulted; - struct ftrace_graph_ent trace; unsigned long return_hooker = (unsigned long) &return_to_handler;
@@ -1046,19 +1045,7 @@ void prepare_ftrace_return(unsigned long return; }
- 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, parent)) *parent = old; - return; - } - - if (ftrace_push_return_trace(old, self_addr, &trace.depth, - frame_pointer, parent) == -EBUSY) { - *parent = old; - return; - } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */