anchor.diff:            ((or (logbitp +page-fault-error-present+ info)
                  (logbitp +page-fault-error-user+ info)
                  (logbitp +page-fault-error-reserved-violation+ info))
  -           (debug-print-line "Fault addr: " fault-addr)
  -           (unhandled-interrupt interrupt-frame info "page fault"))
  +           (fatal-page-fault interrupt-frame info "Page fault" fault-addr))
             (t ;; Non-present page. Try to load it from the store.
              ;; Will not return.
              (wait-for-page-via-interrupt interrupt-frame fault-addr)))))
  
positive.code:                       (* 512 1024 1024 1024))))
             ;; Pages below 2G are wired and should never be unmapped or protected.
             ;; Same for pages in the wired stack area.
             (debug-print-line "Fault addr: " fault-addr)
             (unhandled-interrupt interrupt-frame info "page fault in wired area"))
            ((and (logbitp +page-fault-error-present+ info)
                  (logbitp +page-fault-error-write+ info))
             ;; Copy on write page.
  
negative.code: 
  (defvar *pagefault-hook* nil)
  
  (defun fatal-page-fault (interrupt-frame info reason address)
    (declare (ignore interrupt-frame info))
    (panic reason " on address " address))
  
  (defun sys.int::%page-fault-handler (interrupt-frame info)
    (let* ((fault-addr (sys.int::%cr2)))
      (when (and (boundp '*pagefault-hook*)
                 *pagefault-hook*)
        (funcall *pagefault-hook* interrupt-frame info fault-addr))
      (cond ((not *paging-disk*)
             (fatal-page-fault interrupt-frame info "Early page fault" fault-addr))
            ((not (logtest #x200 (interrupt-frame-raw-register interrupt-frame :rflags)))
             ;; IRQs must be enabled when a page fault occurs.
             (fatal-page-fault interrupt-frame info "Page fault with interrupts disabled" fault-addr))
            ((or (<= 0 fault-addr (1- (* 2 1024 1024 1024)))
                 (<= (ash sys.int::+address-tag-stack+ sys.int::+address-tag-shift+)
                     fault-addr
  