HelenOS sources

boot/arch/arm64/include/arch/barrier.h
kernel/arch/arm32/include/arch/barrier.h
kernel/arch/arm64/include/arch/barrier.h
kernel/arch/ia64/include/arch/barrier.h
kernel/arch/sparc64/include/arch/barrier.h
kernel/generic/include/barrier.h
uspace/lib/c/include/barrier.h
uspace/lib/posix/include/libc/barrier.h
HelenOS homepage, sources at GitHub