1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
/* $Id: dtlb_prot.S,v 1.18 1999/03/02 15:42:14 jj Exp $
* dtlb_prot.S: DTLB protection trap strategy.
* This is included directly into the trap table.
*
* Copyright (C) 1996,1998 David S. Miller (davem@dm.cobaltmicro.com)
* Copyright (C) 1997,1998 Jakub Jelinek (jj@ultra.linux.cz)
*/
#define TAG_CONTEXT_BITS 0x3ff
#define VPTE_SHIFT (PAGE_SHIFT - 3)
#define MODIFIED_BITS (_PAGE_WRITE | _PAGE_W | _PAGE_MODIFIED | _PAGE_ACCESSED)
/* Ways we can get here:
*
* [TL == 0] 1) User stores to readonly pages.
* [TL == 0] 2) Nucleus stores to user readonly pages.
* [TL > 0] 3) Nucleus stores to user readonly stack frame.
*/
/* PROT ** ICACHE line 1: User DTLB protection trap */
ldxa [%g1] ASI_DMMU, %g6 ! Primary or Secondary ctx?
and %g6, 0x10, %g6 ! Get pri/sec ctx bit
stxa %g0, [%g1] ASI_DMMU ! Clear SFSR FaultValid bit
membar #Sync ! Synchronize ASI stores
ldxa [%g1 + %g1] ASI_DMMU, %g4 ! Load TAG_ACCESS
andn %g4, TAG_CONTEXT_BITS, %g4 ! Clear CTX bits
stxa %g0, [%g4 + %g6] ASI_DMMU_DEMAP ! Perform TLB flush of page
membar #Sync ! Synchronize ASI stores
/* PROT ** ICACHE line 2: Further normal processing */
srax %g4, VPTE_SHIFT, %g6 ! Compute VPTE offset
ldxa [%g3 + %g6] ASI_S, %g5 ! Load PTE entry
andcc %g5, _PAGE_WRITE, %g0 ! Writable page?
be,pt %xcc, 1f ! Nope, real fault
or %g5, (MODIFIED_BITS), %g5 ! Mark as writable/modified
stxa %g5, [%g3 + %g6] ASI_S ! Update PTE entry
stxa %g5, [%g0] ASI_DTLB_DATA_IN ! Load PTE into TLB
retry ! Trap return
/* PROT ** ICACHE line 3: Real user faults */
1: rdpr %pstate, %g5 ! Move into alternate globals
wrpr %g5, PSTATE_AG|PSTATE_MG, %pstate
rdpr %tl, %g4 ! Need to do a winfixup?
cmp %g4, 1 ! Trap level >1?
mov TLB_TAG_ACCESS, %g4 ! Prepare reload of vaddr
bgu,pn %xcc, winfix_trampoline ! Yes, perform winfixup
ldxa [%g4] ASI_DMMU, %g5 ! Put tagaccess in %g5
ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault
/* PROT ** ICACHE line 4: More real fault processing */
mov 1, %g4 ! Indicate this was a write
nop
nop
nop
nop
nop
nop
nop
#undef TAG_CONTEXT_BITS
#undef VPTE_SHIFT
#undef MODIFIED_BITS
|
