HelenOS sources

PERM_IO_MANAGER   334 kernel/generic/src/ddi/ddi.c 	if (!(perms & PERM_IO_MANAGER))
PERM_IO_MANAGER   371 kernel/generic/src/ddi/ddi.c 	if (!(perms & PERM_IO_MANAGER))
PERM_IO_MANAGER   283 kernel/generic/src/main/kinit.c 			    PERM_IO_MANAGER | PERM_IRQ_REG);
HelenOS homepage, sources at GitHub