root/arch/sparc/kernel/dtlb_prot.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * dtlb_prot.S: DTLB protection trap strategy.
   4  *              This is included directly into the trap table.
   5  *
   6  * Copyright (C) 1996,1998 David S. Miller (davem@redhat.com)
   7  * Copyright (C) 1997,1998 Jakub Jelinek   (jj@ultra.linux.cz)
   8  */
   9 
  10 /* Ways we can get here:
  11  *
  12  * [TL == 0] 1) User stores to readonly pages.
  13  * [TL == 0] 2) Nucleus stores to user readonly pages.
  14  * [TL >  0] 3) Nucleus stores to user readonly stack frame.
  15  */
  16 
  17 /* PROT ** ICACHE line 1: User DTLB protection trap     */
  18         mov             TLB_SFSR, %g1
  19         stxa            %g0, [%g1] ASI_DMMU             ! Clear FaultValid bit
  20         membar          #Sync                           ! Synchronize stores
  21         rdpr            %pstate, %g5                    ! Move into alt-globals
  22         wrpr            %g5, PSTATE_AG|PSTATE_MG, %pstate
  23         rdpr            %tl, %g1                        ! Need a winfixup?
  24         cmp             %g1, 1                          ! Trap level >1?
  25         mov             TLB_TAG_ACCESS, %g4             ! For reload of vaddr
  26 
  27 /* PROT ** ICACHE line 2: More real fault processing */
  28         ldxa            [%g4] ASI_DMMU, %g5             ! Put tagaccess in %g5
  29         srlx            %g5, PAGE_SHIFT, %g5
  30         sllx            %g5, PAGE_SHIFT, %g5            ! Clear context ID bits
  31         bgu,pn          %xcc, winfix_trampoline         ! Yes, perform winfixup
  32          mov            FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
  33         ba,pt           %xcc, sparc64_realfault_common  ! Nope, normal fault
  34          nop
  35         nop
  36 
  37 /* PROT ** ICACHE line 3: Unused...     */
  38         nop
  39         nop
  40         nop
  41         nop
  42         nop
  43         nop
  44         nop
  45         nop
  46 
  47 /* PROT ** ICACHE line 4: Unused...     */
  48         nop
  49         nop
  50         nop
  51         nop
  52         nop
  53         nop
  54         nop
  55         nop