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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. #ifdef CONFIG_TSB
  48. #include <arch/mm/tsb.h>
  49. #endif
  50.  
  51. #define TT_FAST_INSTRUCTION_ACCESS_MMU_MISS 0x64
  52. #define TT_FAST_DATA_ACCESS_MMU_MISS        0x68
  53. #define TT_FAST_DATA_ACCESS_PROTECTION      0x6c
  54.  
  55. #define FAST_MMU_HANDLER_SIZE           128
  56.  
  57. #ifdef __ASM__
  58.  
  59. .macro FAST_INSTRUCTION_ACCESS_MMU_MISS_HANDLER
  60.     /*
  61.      * First, try to refill TLB from TSB.
  62.      */
  63. #ifdef CONFIG_TSB
  64.     ldxa [%g0] ASI_IMMU, %g1            ! read TSB Tag Target Register
  65.     ldxa [%g0] ASI_IMMU_TSB_8KB_PTR_REG, %g2    ! read TSB 8K Pointer
  66.     ldda [%g2] ASI_NUCLEUS_QUAD_LDD, %g4        ! 16-byte atomic load into %g4 and %g5
  67.     cmp %g1, %g4                    ! is this the entry we are looking for?
  68.     bne,pn %xcc, 0f
  69.     nop
  70.     stxa %g5, [%g0] ASI_ITLB_DATA_IN_REG        ! copy mapping from ITSB to ITLB
  71.     retry
  72. #endif
  73.  
  74. 0:
  75.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  76.     PREEMPTIBLE_HANDLER fast_instruction_access_mmu_miss
  77. .endm
  78.  
  79. .macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl
  80.     /*
  81.      * First, try to refill TLB from TSB.
  82.      */
  83.  
  84. #ifdef CONFIG_TSB
  85.     ldxa [%g0] ASI_DMMU, %g1            ! read TSB Tag Target Register
  86.     srlx %g1, TSB_TAG_TARGET_CONTEXT_SHIFT, %g2 ! is this a kernel miss?
  87.     brz,pn %g2, 0f
  88.     ldxa [%g0] ASI_DMMU_TSB_8KB_PTR_REG, %g3    ! read TSB 8K Pointer
  89.     ldda [%g3] ASI_NUCLEUS_QUAD_LDD, %g4        ! 16-byte atomic load into %g4 and %g5
  90.     cmp %g1, %g4                    ! is this the entry we are looking for?
  91.     bne,pn %xcc, 0f
  92.     nop
  93.     stxa %g5, [%g0] ASI_DTLB_DATA_IN_REG        ! copy mapping from DTSB to DTLB
  94.     retry
  95. #endif
  96.  
  97.     /*
  98.      * Second, test if it is the portion of the kernel address space
  99.      * which is faulting. If that is the case, immediately create
  100.      * identity mapping for that page in DTLB. VPN 0 is excluded from
  101.      * this treatment.
  102.      *
  103.      * Note that branch-delay slots are used in order to save space.
  104.      */
  105. 0:
  106.     sethi %hi(fast_data_access_mmu_miss_data_hi), %g7
  107.     wr %g0, ASI_DMMU, %asi
  108.     ldxa [VA_DMMU_TAG_ACCESS] %asi, %g1     ! read the faulting Context and VPN
  109.     set TLB_TAG_ACCESS_CONTEXT_MASK, %g2
  110.     andcc %g1, %g2, %g3             ! get Context
  111.     bnz %xcc, 0f                    ! Context is non-zero
  112.     andncc %g1, %g2, %g3                ! get page address into %g3
  113.     bz  %xcc, 0f                    ! page address is zero
  114.     ldx [%g7 + %lo(end_of_identity)], %g4
  115.     cmp %g3, %g4
  116.     bgeu %xcc, 0f
  117.  
  118.     ldx [%g7 + %lo(kernel_8k_tlb_data_template)], %g2
  119.     add %g3, %g2, %g2
  120.     stxa %g2, [%g0] ASI_DTLB_DATA_IN_REG        ! identity map the kernel page
  121.     retry
  122.  
  123.     /*
  124.      * Third, catch and handle special cases when the trap is caused by
  125.      * the userspace register window spill or fill handler. In case
  126.      * one of these two traps caused this trap, we just lower the trap
  127.      * level and service the DTLB miss. In the end, we restart
  128.      * the offending SAVE or RESTORE.
  129.      */
  130. 0:
  131. .if (\tl > 0)
  132.     wrpr %g0, 1, %tl
  133. .endif
  134.  
  135.     /*
  136.      * Switch from the MM globals.
  137.      */
  138.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  139.  
  140.     /*
  141.      * Read the Tag Access register for the higher-level handler.
  142.      * This is necessary to survive nested DTLB misses.
  143.      */
  144.     ldxa [VA_DMMU_TAG_ACCESS] %asi, %g2
  145.  
  146.     /*
  147.      * g2 will be passed as an argument to fast_data_access_mmu_miss().
  148.      */
  149.     PREEMPTIBLE_HANDLER fast_data_access_mmu_miss
  150. .endm
  151.  
  152. .macro FAST_DATA_ACCESS_PROTECTION_HANDLER tl
  153.     /*
  154.      * The same special case as in FAST_DATA_ACCESS_MMU_MISS_HANDLER.
  155.      */
  156.  
  157. .if (\tl > 0)
  158.     wrpr %g0, 1, %tl
  159. .endif
  160.  
  161.     /*
  162.      * Switch from the MM globals.
  163.      */
  164.     wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate
  165.  
  166.     /*
  167.      * Read the Tag Access register for the higher-level handler.
  168.      * This is necessary to survive nested DTLB misses.
  169.      */
  170.     mov VA_DMMU_TAG_ACCESS, %g2
  171.     ldxa [%g2] ASI_DMMU, %g2
  172.  
  173.     /*
  174.      * g2 will be passed as an argument to fast_data_access_mmu_miss().
  175.      */
  176.     PREEMPTIBLE_HANDLER fast_data_access_protection
  177. .endm
  178.  
  179. #endif /* __ASM__ */
  180.  
  181. #endif
  182.  
  183. /** @}
  184.  */
  185.