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  1. /*
  2.  * Copyright (C) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup sparc64interrupt
  30.  * @{
  31.  */
  32. /**
  33.  * @file
  34.  * @brief This file contains fast MMU trap handlers.
  35.  */
  36.  
  37. #ifndef KERN_sparc64_MMU_TRAP_H_
  38. #define KERN_sparc64_MMU_TRAP_H_
  39.  
  40. #include <arch/stack.h>
  41. #include <arch/regdef.h>
  42. #include <arch/mm/tlb.h>
  43. #include <arch/mm/mmu.h>
  44. #include <arch/mm/tte.h>
  45. #include <arch/trap/regwin.h>
  46.  
  47. #define TT_FAST_INSTRUCTION_ACCESS_MMU_MISS 0x64
  48. #define TT_FAST_DATA_ACCESS_MMU_MISS        0x68
  49. #define TT_FAST_DATA_ACCESS_PROTECTION      0x6c
  50.  
  51. #define FAST_MMU_HANDLER_SIZE           128
  52.  
  53. #ifdef __ASM__
  54.  
  55. .macro FAST_INSTRUCTION_ACCESS_MMU_MISS_HANDLER
  56.     /*
  57.      * First, try to refill TLB from TSB.
  58.      */
  59.     ! TODO
  60.  
  61.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  62.     PREEMPTIBLE_HANDLER fast_instruction_access_mmu_miss
  63. .endm
  64.  
  65. .macro FAST_DATA_ACCESS_MMU_MISS_HANDLER
  66.     /*
  67.      * First, try to refill TLB from TSB.
  68.      */
  69.     ! TODO
  70.  
  71.     /*
  72.      * Second, test if it is the portion of the kernel address space
  73.      * which is faulting. If that is the case, immediately create
  74.      * identity mapping for that page in DTLB. VPN 0 is excluded from
  75.      * this treatment.
  76.      *
  77.      * Note that branch-delay slots are used in order to save space.
  78.      */
  79.  
  80.     mov VA_DMMU_TAG_ACCESS, %g1
  81.     ldxa [%g1] ASI_DMMU, %g1            ! read the faulting Context and VPN
  82.     set TLB_TAG_ACCESS_CONTEXT_MASK, %g2
  83.     andcc %g1, %g2, %g3             ! get Context
  84.     bnz 0f                      ! Context is non-zero
  85.     andncc %g1, %g2, %g3                ! get page address into %g3
  86.     bz 0f                       ! page address is zero
  87.  
  88.     or %g3, (TTE_CP|TTE_P|TTE_W), %g2       ! 8K pages are the default (encoded as 0)
  89.     mov 1, %g3
  90.     sllx %g3, TTE_V_SHIFT, %g3
  91.     or %g2, %g3, %g2
  92.     stxa %g2, [%g0] ASI_DTLB_DATA_IN_REG        ! identity map the kernel page
  93.     retry
  94.  
  95.     /*
  96.      * Third, catch and handle special cases when the trap is caused by
  97.      * the userspace register window spill or fill handler. In case
  98.      * one of these two traps caused this trap, we just lower the trap
  99.      * level and service the DTLB miss. In the end, we restart
  100.      * the offending SAVE or RESTORE.
  101.      */
  102. 0:
  103.     HANDLE_MMU_TRAPS_FROM_SPILL_OR_FILL
  104.  
  105.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  106.     PREEMPTIBLE_HANDLER fast_data_access_mmu_miss
  107. .endm
  108.  
  109. .macro FAST_DATA_ACCESS_PROTECTION_HANDLER
  110.     /*
  111.      * First, try to refill TLB from TSB.
  112.      */
  113.     ! TODO
  114.  
  115.     /*
  116.      * The same special case as in FAST_DATA_ACCESS_MMU_MISS_HANDLER.
  117.      */
  118.     HANDLE_MMU_TRAPS_FROM_SPILL_OR_FILL
  119.  
  120.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  121.     PREEMPTIBLE_HANDLER fast_data_access_protection
  122. .endm
  123.  
  124. /*
  125.  * Macro used to lower TL when a MMU trap is caused by
  126.  * the userspace register window spill or fill handler.
  127.  */
  128. .macro HANDLE_MMU_TRAPS_FROM_SPILL_OR_FILL
  129.     rdpr %tl, %g1
  130.     dec %g1
  131.     brz %g1, 0f         ! if TL was 1, skip
  132.     nop
  133.     wrpr %g1, 0, %tl        ! TL--
  134.     rdpr %tt, %g2
  135.     cmp %g2, TT_SPILL_1_NORMAL
  136.     be 0f               ! trap from spill_1_normal
  137.     cmp %g2, TT_FILL_1_NORMAL
  138.     be 0f               ! trap from fill_1_normal
  139.     inc %g1
  140.     wrpr %g1, 0, %tl        ! another trap, TL++
  141. 0:
  142. .endm
  143.  
  144. #endif /* __ASM__ */
  145.  
  146. #endif
  147.  
  148. /** @}
  149.  */
  150.