1/* 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 mov TLB_SFSR, %g1 18 stxa %g0, [%g1] ASI_DMMU ! Clear FaultValid bit 19 membar #Sync ! Synchronize stores 20 rdpr %pstate, %g5 ! Move into alt-globals 21 wrpr %g5, PSTATE_AG|PSTATE_MG, %pstate 22 rdpr %tl, %g1 ! Need a winfixup? 23 cmp %g1, 1 ! Trap level >1? 24 mov TLB_TAG_ACCESS, %g4 ! For reload of vaddr 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 55