arch/sparc64/kernel/dtlb_prot.S

   1 /* $Id: dtlb_prot.S,v 1.22 2001/04/11 23:40:32 davem Exp $
   2  * dtlb_prot.S: DTLB protection trap strategy.
   3  *              This is included directly into the trap table.
   4  *
   5  * Copyright (C) 1996,1998 David S. Miller (davem@redhat.com)
   6  * Copyright (C) 1997,1998 Jakub Jelinek   (jj@ultra.linux.cz)
   7  */
   8
   9 /* Ways we can get here:
  10  *
  11  * [TL == 0] 1) User stores to readonly pages.
  12  * [TL == 0] 2) Nucleus stores to user readonly pages.
  13  * [TL >  0] 3) Nucleus stores to user readonly stack frame.
  14  */
  15
  16 /* PROT ** ICACHE line 1: User DTLB protection trap     */
  17         stxa            %g0, [%g1] ASI_DMMU             ! Clear SFSR FaultValid bit
  18         membar          #Sync                           ! Synchronize ASI stores
  19         rdpr            %pstate, %g5                    ! Move into alternate globals
  20         wrpr            %g5, PSTATE_AG|PSTATE_MG, %pstate
  21         rdpr            %tl, %g1                        ! Need to do a winfixup?
  22         cmp             %g1, 1                          ! Trap level >1?
  23         mov             TLB_TAG_ACCESS, %g4             ! Prepare reload of vaddr
  24         nop
  25
  26 /* PROT ** ICACHE line 2: More real fault processing */
  27         bgu,pn          %xcc, winfix_trampoline         ! Yes, perform winfixup
  28          ldxa           [%g4] ASI_DMMU, %g5             ! Put tagaccess in %g5
  29         ba,pt           %xcc, sparc64_realfault_common  ! Nope, normal fault
  30          mov            FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
  31         nop
  32         nop
  33         nop
  34         nop
  35
  36 /* PROT ** ICACHE line 3: Unused...     */
  37         nop
  38         nop
  39         nop
  40         nop
  41         nop
  42         nop
  43         nop
  44         nop
  45
  46 /* PROT ** ICACHE line 4: Unused...     */
  47         nop
  48         nop
  49         nop
  50         nop
  51         nop
  52         nop
  53         nop
  54         nop