[PATCH 4/4] x86,objtool: Explicitly mark idtentry_body()s tail REACHABLE

[Peter Zijlstra]

Objtool can figure out that some \cfunc()s are noreturn and then
complains about certain instances having unreachable tails:

  vmlinux.o: warning: objtool: asm_exc_xen_unknown_trap()+0x16: unreachable instruction

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/x86/entry/entry_64.S |    3 +++
 1 file changed, 3 insertions(+)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -337,6 +337,9 @@ SYM_CODE_END(ret_from_fork)
 
 	call	\cfunc
 
+	/* For some configurations \cfunc ends up being a noreturn. */
+	REACHABLE
+
 	jmp	error_return
 .endm