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/*
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/*
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 * Handler of the Fast Data Access MMU Miss trap. If the trap occurred in the kernel
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 * Handler of the Fast Data Access MMU Miss trap. If the trap occurred in the kernel
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 * (context 0), an identity mapping (with displacement) is installed. Otherwise
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 * (context 0), an identity mapping (with displacement) is installed. Otherwise
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 * a higher level service routine is called.
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 * a higher level service routine is called.
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 *
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 * TODO implement calling the higher level service routine
 - 
 
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 */
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 */
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.macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl
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.macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl
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    mov SCRATCHPAD_MMU_FSA, %g1
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    mov SCRATCHPAD_MMU_FSA, %g1
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    ldxa [%g1] ASI_SCRATCHPAD, %g1          ! g1 <= RA of MMU fault status area
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    ldxa [%g1] ASI_SCRATCHPAD, %g1          ! g1 <= RA of MMU fault status area
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    /* service by higher-level routine when context != 0 */
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    /* read faulting context */
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    add %g1, FSA_DFC_OFFSET, %g2            ! g2 <= RA of data fault context
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    add %g1, FSA_DFC_OFFSET, %g2            ! g2 <= RA of data fault context
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    ldxa [%g2] ASI_REAL, %g3            ! read the fault context
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    ldxa [%g2] ASI_REAL, %g3            ! read the fault context
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    brnz %g3, 0f
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    nop
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    /* read the faulting address */
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    /* read the faulting address */
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    add %g1, FSA_DFA_OFFSET, %g2            ! g2 <= RA of data fault address
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    add %g1, FSA_DFA_OFFSET, %g2            ! g2 <= RA of data fault address
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    ldxa [%g2] ASI_REAL, %g1            ! read the fault address
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    ldxa [%g2] ASI_REAL, %g1            ! read the fault address
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    srlx %g1, TTE_DATA_TADDR_OFFSET, %g1        ! truncate it to page boundary
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    srlx %g1, TTE_DATA_TADDR_OFFSET, %g1        ! truncate it to page boundary
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    sllx %g1, TTE_DATA_TADDR_OFFSET, %g1
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    sllx %g1, TTE_DATA_TADDR_OFFSET, %g1
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- 
 
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    /* service by higher-level routine when context != 0 */
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    brnz %g3, 0f
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    nop
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    /* exclude page number 0 from installing the identity mapping */
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    /* exclude page number 0 from installing the identity mapping */
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    brz %g1, 0f
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    brz %g1, 0f
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    nop
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    nop
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- 
 
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    /*
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    /* installing the identity does not fit into 32 instructions, call a separate routine */
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     * Installing the identity does not fit into 32 instructions, call
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     * a separate routine. The routine performs RETRY, hence the call never
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     * returns.
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     */
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    ba install_identity_mapping
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    ba install_identity_mapping
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    nop
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    nop
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- 
 
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    0:
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- 
 
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    /*
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     * One of the scenarios in which this trap can occur is when the
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     * register window spill/fill handler accesses a memory which is not
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     * mapped. In such a case, this handler will be called from TL = 1.
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     * We handle the situation by pretending that the MMU miss occurred
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     * on TL = 0. Once the MMU miss trap is services, the instruction which
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     * caused the spill/fill trap is restarted, the spill/fill trap occurs,
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     * but this time its handler accesse memory which IS mapped.
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     */
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    .if (\tl > 0)
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        wrpr %g0, 1, %tl
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    .endif
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    /*
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     * Save the faulting virtual page and faulting context to the %g2
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     * register. The most significant 51 bits of the %g2 register will
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     * contain the virtual address which caused the fault truncated to the
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     * page boundary. The least significant 13 bits of the %g2 register
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     * will contain the number of the context in which the fault occurred.
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     * The value of the %g2 register will be passed as a parameter to the
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    0: ! TODO - call higher level service routine
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     * higher level service routine.
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     */
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    or %g1, %g3, %g2
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- 
 
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    PREEMPTIBLE_HANDLER fast_data_access_mmu_miss
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.endm
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.endm
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- 
 
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/*
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 * Handler of the Fast Data MMU Protection trap. Finds the trapping address
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 * and context and calls higher level service routine.
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 */
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.macro FAST_DATA_ACCESS_PROTECTION_HANDLER tl
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.macro FAST_DATA_ACCESS_PROTECTION_HANDLER tl
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    /*
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     * The same special case as in FAST_DATA_ACCESS_MMU_MISS_HANDLER.
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     */
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    .if (\tl > 0)
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        wrpr %g0, 1, %tl
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    .endif
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    mov SCRATCHPAD_MMU_FSA, %g1
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    ldxa [%g1] ASI_SCRATCHPAD, %g1          ! g1 <= RA of MMU fault status area
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    /* read faulting context */
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    add %g1, FSA_DFC_OFFSET, %g2            ! g2 <= RA of data fault context
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    ldxa [%g2] ASI_REAL, %g3            ! read the fault context
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    /* read the faulting address */
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    add %g1, FSA_DFA_OFFSET, %g2            ! g2 <= RA of data fault address
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    ldxa [%g2] ASI_REAL, %g1            ! read the fault address
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    srlx %g1, TTE_DATA_TADDR_OFFSET, %g1        ! truncate it to page boundary
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    sllx %g1, TTE_DATA_TADDR_OFFSET, %g1
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    /* the same as for FAST_DATA_ACCESS_MMU_MISS_HANDLER */
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    or %g1, %g3, %g2
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- 
 
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    PREEMPTIBLE_HANDLER fast_data_access_protection
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.endm
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.endm
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#endif /* __ASM__ */
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#endif /* __ASM__ */
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#endif
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#endif