| 1 | /*
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| 2 | * Copyright (c) 2006 Jakub Jermar
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup sparc64interrupt
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| 30 | * @{
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| 31 | */
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| 32 | /**
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| 33 | * @file
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| 34 | * @brief This file contains fast MMU trap handlers.
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| 35 | */
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| 36 |
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| 37 | #ifndef KERN_sparc64_SUN4U_MMU_TRAP_H_
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| 38 | #define KERN_sparc64_SUN4U_MMU_TRAP_H_
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| 39 |
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| 40 | #include <arch/stack.h>
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| 41 | #include <arch/regdef.h>
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| 42 | #include <arch/mm/tlb.h>
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| 43 | #include <arch/mm/mmu.h>
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| 44 | #include <arch/mm/tte.h>
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| 45 | #include <arch/trap/regwin.h>
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| 46 |
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| 47 | #ifdef CONFIG_TSB
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| 48 | #include <arch/mm/tsb.h>
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| 49 | #endif
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| 50 |
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| 51 | #define TT_FAST_INSTRUCTION_ACCESS_MMU_MISS 0x64
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| 52 | #define TT_FAST_DATA_ACCESS_MMU_MISS 0x68
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| 53 | #define TT_FAST_DATA_ACCESS_PROTECTION 0x6c
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| 54 |
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| 55 | #define FAST_MMU_HANDLER_SIZE 128
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| 56 |
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| 57 | #ifdef __ASM__
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| 58 |
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| 59 | .macro FAST_INSTRUCTION_ACCESS_MMU_MISS_HANDLER
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| 60 | /*
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| 61 | * First, try to refill TLB from TSB.
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| 62 | */
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| 63 | #ifdef CONFIG_TSB
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| 64 | ldxa [%g0] ASI_IMMU, %g1 ! read TSB Tag Target Register
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| 65 | ldxa [%g0] ASI_IMMU_TSB_8KB_PTR_REG, %g2 ! read TSB 8K Pointer
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| 66 | ldda [%g2] ASI_NUCLEUS_QUAD_LDD, %g4 ! 16-byte atomic load into %g4 and %g5
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| 67 | cmp %g1, %g4 ! is this the entry we are looking for?
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| 68 | bne,pn %xcc, 0f
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| 69 | nop
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| 70 | stxa %g5, [%g0] ASI_ITLB_DATA_IN_REG ! copy mapping from ITSB to ITLB
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| 71 | retry
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| 72 | #endif
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| 73 |
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| 74 | 0:
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| 75 | wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
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| 76 | PREEMPTIBLE_HANDLER fast_instruction_access_mmu_miss
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| 77 | .endm
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| 78 |
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| 79 | .macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl
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| 80 | /*
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| 81 | * First, try to refill TLB from TSB.
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| 82 | */
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| 83 |
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| 84 | #ifdef CONFIG_TSB
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| 85 | ldxa [%g0] ASI_DMMU, %g1 ! read TSB Tag Target Register
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| 86 | srlx %g1, TSB_TAG_TARGET_CONTEXT_SHIFT, %g2 ! is this a kernel miss?
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| 87 | brz,pn %g2, 0f
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| 88 | ldxa [%g0] ASI_DMMU_TSB_8KB_PTR_REG, %g3 ! read TSB 8K Pointer
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| 89 | ldda [%g3] ASI_NUCLEUS_QUAD_LDD, %g4 ! 16-byte atomic load into %g4 and %g5
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| 90 | cmp %g1, %g4 ! is this the entry we are looking for?
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| 91 | bne,pn %xcc, 0f
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| 92 | nop
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| 93 | stxa %g5, [%g0] ASI_DTLB_DATA_IN_REG ! copy mapping from DTSB to DTLB
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| 94 | retry
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| 95 | #endif
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| 96 |
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| 97 | /*
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| 98 | * Second, test if it is the portion of the kernel address space
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| 99 | * which is faulting. If that is the case, immediately create
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| 100 | * identity mapping for that page in DTLB. VPN 0 is excluded from
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| 101 | * this treatment.
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| 102 | *
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| 103 | * Note that branch-delay slots are used in order to save space.
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| 104 | */
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| 105 | 0:
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| 106 | sethi %hi(fast_data_access_mmu_miss_data_hi), %g7
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| 107 | wr %g0, ASI_DMMU, %asi
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| 108 | ldxa [VA_DMMU_TAG_ACCESS] %asi, %g1 ! read the faulting Context and VPN
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| 109 | set TLB_TAG_ACCESS_CONTEXT_MASK, %g2
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| 110 | andcc %g1, %g2, %g3 ! get Context
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| 111 | bnz %xcc, 0f ! Context is non-zero
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| 112 | andncc %g1, %g2, %g3 ! get page address into %g3
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| 113 | bz %xcc, 0f ! page address is zero
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| 114 | ldx [%g7 + %lo(end_of_identity)], %g4
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| 115 | cmp %g3, %g4
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| 116 | bgeu %xcc, 0f
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| 117 |
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| 118 | ldx [%g7 + %lo(kernel_8k_tlb_data_template)], %g2
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| 119 | add %g3, %g2, %g2
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| 120 | stxa %g2, [%g0] ASI_DTLB_DATA_IN_REG ! identity map the kernel page
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| 121 | retry
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| 122 |
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| 123 | /*
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| 124 | * Third, catch and handle special cases when the trap is caused by
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| 125 | * the userspace register window spill or fill handler. In case
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| 126 | * one of these two traps caused this trap, we just lower the trap
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| 127 | * level and service the DTLB miss. In the end, we restart
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| 128 | * the offending SAVE or RESTORE.
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| 129 | */
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| 130 | 0:
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| 131 | .if (\tl > 0)
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| 132 | wrpr %g0, 1, %tl
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| 133 | .endif
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| 134 |
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| 135 | /*
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| 136 | * Switch from the MM globals.
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| 137 | */
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| 138 | wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
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| 139 |
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| 140 | /*
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| 141 | * Read the Tag Access register for the higher-level handler.
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| 142 | * This is necessary to survive nested DTLB misses.
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| 143 | */
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| 144 | ldxa [VA_DMMU_TAG_ACCESS] %asi, %g2
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| 145 |
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| 146 | /*
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| 147 | * g2 will be passed as an argument to fast_data_access_mmu_miss().
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| 148 | */
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| 149 | PREEMPTIBLE_HANDLER fast_data_access_mmu_miss
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| 150 | .endm
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| 151 |
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| 152 | .macro FAST_DATA_ACCESS_PROTECTION_HANDLER tl
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| 153 | /*
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| 154 | * The same special case as in FAST_DATA_ACCESS_MMU_MISS_HANDLER.
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| 155 | */
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| 156 |
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| 157 | .if (\tl > 0)
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| 158 | wrpr %g0, 1, %tl
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| 159 | .endif
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| 160 |
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| 161 | /*
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| 162 | * Switch from the MM globals.
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| 163 | */
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| 164 | wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
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| 165 |
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| 166 | /*
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| 167 | * Read the Tag Access register for the higher-level handler.
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| 168 | * This is necessary to survive nested DTLB misses.
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| 169 | */
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| 170 | mov VA_DMMU_TAG_ACCESS, %g2
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| 171 | ldxa [%g2] ASI_DMMU, %g2
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| 172 |
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| 173 | /*
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| 174 | * g2 will be passed as an argument to fast_data_access_mmu_miss().
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| 175 | */
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| 176 | PREEMPTIBLE_HANDLER fast_data_access_protection
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| 177 | .endm
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| 178 |
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| 179 | #endif /* __ASM__ */
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| 180 |
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| 181 | #endif
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| 182 |
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| 183 | /** @}
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| 184 | */
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