In file included from arch/mips/kernel/ptrace.c:42:0:
arch/mips/kernel/ptrace.c: In function ‘mips_get_syscall_arg’:
/home/ralf/src/linux/linux-mips/arch/mips/include/asm/syscall.h:60:1: error: control reaches end of non-void function [-Werror=return-type]
cc1: all warnings being treated as errors
make: *** [arch/mips/kernel/ptrace.o] Error 1
make: *** [arch/mips/kernel] Error 2
make: *** [arch/mips] Error 2
Fixed by marking the end of mips_get_syscall_arg() as unreachable.