From b83b43ffc6e4b514ca034a0fbdee01322e2f7022 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 15 Oct 2019 09:00:55 -0400 Subject: fgraph: Fix function type mismatches of ftrace_graph_return using ftrace_stub The C compiler is allowing more checks to make sure that function pointers are assigned to the correct prototype function. Unfortunately, the function graph tracer uses a special name with its assigned ftrace_graph_return function pointer that maps to a stub function used by the function tracer (ftrace_stub). The ftrace_graph_return variable is compared to the ftrace_stub in some archs to know if the function graph tracer is enabled or not. This means we can not just simply create a new function stub that compares it without modifying all the archs. Instead, have the linker script create a function_graph_stub that maps to ftrace_stub, and this way we can define the prototype for it to match the prototype of ftrace_graph_return, and make the compiler checks all happy! Link: http://lkml.kernel.org/r/20191015090055.789a0aed@gandalf.local.home Cc: linux-sh@vger.kernel.org Cc: Yoshinori Sato Cc: Rich Felker Reported-by: Sami Tolvanen Signed-off-by: Steven Rostedt (VMware) --- arch/sh/boot/compressed/misc.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/sh') diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c index c15cac9251b9..e69ec12cbbe6 100644 --- a/arch/sh/boot/compressed/misc.c +++ b/arch/sh/boot/compressed/misc.c @@ -111,6 +111,11 @@ void __stack_chk_fail(void) error("stack-protector: Kernel stack is corrupted\n"); } +/* Needed because vmlinux.lds.h references this */ +void ftrace_stub(void) +{ +} + #ifdef CONFIG_SUPERH64 #define stackalign 8 #else -- cgit v1.2.3-59-g8ed1b