/usr/include/xenomai/asm-arm/ is in libxenomai-dev 2.6.4+dfsg-0.2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/xenomai/asm-arm/arith.h
/usr/include/xenomai/asm-arm/atomic.h
/usr/include/xenomai/asm-arm/atomic_asm.h
/usr/include/xenomai/asm-arm/bits/
/usr/include/xenomai/asm-arm/bits/bind.h
/usr/include/xenomai/asm-arm/bits/heap.h
/usr/include/xenomai/asm-arm/bits/init.h
/usr/include/xenomai/asm-arm/bits/intr.h
/usr/include/xenomai/asm-arm/bits/pod.h
/usr/include/xenomai/asm-arm/bits/sched.h
/usr/include/xenomai/asm-arm/bits/shadow.h
/usr/include/xenomai/asm-arm/bits/thread.h
/usr/include/xenomai/asm-arm/bits/timer.h
/usr/include/xenomai/asm-arm/calibration.h
/usr/include/xenomai/asm-arm/features.h
/usr/include/xenomai/asm-arm/fptest.h
/usr/include/xenomai/asm-arm/hal.h
/usr/include/xenomai/asm-arm/syscall.h
/usr/include/xenomai/asm-arm/system.h
/usr/include/xenomai/asm-arm/tsc.h
/usr/include/xenomai/asm-arm/wrappers.h