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1da177e4 LT |
1 | /* $Id: itlb_base.S,v 1.12 2002/02/09 19:49:30 davem Exp $ |
2 | * itlb_base.S: Front end to ITLB miss replacement 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 | #if PAGE_SHIFT == 13 | |
10 | /* | |
11 | * To compute vpte offset, we need to do ((addr >> 13) << 3), | |
12 | * which can be optimized to (addr >> 10) if bits 10/11/12 can | |
13 | * be guaranteed to be 0 ... mmu_context.h does guarantee this | |
14 | * by only using 10 bits in the hwcontext value. | |
15 | */ | |
16 | #define CREATE_VPTE_OFFSET1(r1, r2) \ | |
17 | srax r1, 10, r2 | |
c9c10830 | 18 | #define CREATE_VPTE_OFFSET2(r1, r2) nop |
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19 | #else /* PAGE_SHIFT */ |
20 | #define CREATE_VPTE_OFFSET1(r1, r2) \ | |
21 | srax r1, PAGE_SHIFT, r2 | |
22 | #define CREATE_VPTE_OFFSET2(r1, r2) \ | |
23 | sllx r2, 3, r2 | |
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24 | #endif /* PAGE_SHIFT */ |
25 | ||
26 | ||
27 | /* Ways we can get here: | |
28 | * | |
29 | * 1) Nucleus instruction misses from module code. | |
30 | * 2) All user instruction misses. | |
31 | * | |
32 | * All real page faults merge their code paths to the | |
33 | * sparc64_realfault_common label below. | |
34 | */ | |
35 | ||
36 | /* ITLB ** ICACHE line 1: Quick user TLB misses */ | |
c9c10830 | 37 | mov TLB_SFSR, %g1 |
1da177e4 LT |
38 | ldxa [%g1 + %g1] ASI_IMMU, %g4 ! Get TAG_ACCESS |
39 | CREATE_VPTE_OFFSET1(%g4, %g6) ! Create VPTE offset | |
40 | CREATE_VPTE_OFFSET2(%g4, %g6) ! Create VPTE offset | |
41 | ldxa [%g3 + %g6] ASI_P, %g5 ! Load VPTE | |
42 | 1: brgez,pn %g5, 3f ! Not valid, branch out | |
43 | sethi %hi(_PAGE_EXEC), %g4 ! Delay-slot | |
44 | andcc %g5, %g4, %g0 ! Executable? | |
c9c10830 DM |
45 | |
46 | /* ITLB ** ICACHE line 2: Real faults */ | |
1da177e4 LT |
47 | be,pn %xcc, 3f ! Nope, branch. |
48 | nop ! Delay-slot | |
49 | 2: stxa %g5, [%g0] ASI_ITLB_DATA_IN ! Load PTE into TLB | |
50 | retry ! Trap return | |
c9c10830 | 51 | 3: rdpr %pstate, %g4 ! Move into alt-globals |
1da177e4 LT |
52 | wrpr %g4, PSTATE_AG|PSTATE_MG, %pstate |
53 | rdpr %tpc, %g5 ! And load faulting VA | |
54 | mov FAULT_CODE_ITLB, %g4 ! It was read from ITLB | |
c9c10830 DM |
55 | |
56 | /* ITLB ** ICACHE line 3: Finish faults */ | |
57 | sparc64_realfault_common: ! Called by dtlb_miss | |
1da177e4 LT |
58 | stb %g4, [%g6 + TI_FAULT_CODE] |
59 | stx %g5, [%g6 + TI_FAULT_ADDR] | |
60 | ba,pt %xcc, etrap ! Save state | |
61 | 1: rd %pc, %g7 ! ... | |
1da177e4 LT |
62 | call do_sparc64_fault ! Call fault handler |
63 | add %sp, PTREGS_OFF, %o0! Compute pt_regs arg | |
64 | ba,pt %xcc, rtrap_clr_l6 ! Restore cpu state | |
65 | nop | |
c9c10830 DM |
66 | |
67 | /* ITLB ** ICACHE line 4: Window fixups */ | |
1da177e4 LT |
68 | winfix_trampoline: |
69 | rdpr %tpc, %g3 ! Prepare winfixup TNPC | |
c9c10830 | 70 | or %g3, 0x7c, %g3 ! Compute branch offset |
1da177e4 LT |
71 | wrpr %g3, %tnpc ! Write it into TNPC |
72 | done ! Do it to it | |
1da177e4 LT |
73 | nop |
74 | nop | |
75 | nop | |
76 | nop | |
1da177e4 LT |
77 | |
78 | #undef CREATE_VPTE_OFFSET1 | |
79 | #undef CREATE_VPTE_OFFSET2 |