HelenOS sources

phys_page_fault    57 kernel/generic/src/mm/backend_phys.c static int phys_page_fault(as_area_t *, uintptr_t, pf_access_t);
phys_page_fault    76 kernel/generic/src/mm/backend_phys.c 	.page_fault = phys_page_fault,
HelenOS homepage, sources at GitHub