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/*

 * Copyright (c) 2006 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup sparc64interrupt

 * @{

 */

/**

 * @file

 * @brief This file contains fast MMU trap handlers.

 */

#ifndef KERN_sparc64_MMU_TRAP_H_

#define KERN_sparc64_MMU_TRAP_H_

#include <arch/stack.h>

#include <arch/regdef.h>

#include <arch/mm/tlb.h>

#include <arch/mm/mmu.h>

#include <arch/mm/tte.h>

#include <arch/trap/regwin.h>

#ifdef CONFIG_TSB

#include <arch/mm/tsb.h>

#endif

#define TT_FAST_INSTRUCTION_ACCESS_MMU_MISS 0x64

#define TT_FAST_DATA_ACCESS_MMU_MISS        0x68

#define TT_FAST_DATA_ACCESS_PROTECTION      0x6c

#define FAST_MMU_HANDLER_SIZE           128

#ifdef __ASM__

.macro FAST_INSTRUCTION_ACCESS_MMU_MISS_HANDLER

    /*

     * First, try to refill TLB from TSB.

     */

#ifdef CONFIG_TSB

    ldxa [%g0] ASI_IMMU, %g1            ! read TSB Tag Target Register

    ldxa [%g0] ASI_IMMU_TSB_8KB_PTR_REG, %g2    ! read TSB 8K Pointer

    ldda [%g2] ASI_NUCLEUS_QUAD_LDD, %g4        ! 16-byte atomic load into %g4 and %g5

    cmp %g1, %g4                    ! is this the entry we are looking for?

    bne,pn %xcc, 0f

    nop

    stxa %g5, [%g0] ASI_ITLB_DATA_IN_REG        ! copy mapping from ITSB to ITLB

    retry

#endif

0:

    wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate

    PREEMPTIBLE_HANDLER fast_instruction_access_mmu_miss

.endm

.macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl

    /*

     * First, try to refill TLB from TSB.

     */

#ifdef CONFIG_TSB

    ldxa [%g0] ASI_DMMU, %g1            ! read TSB Tag Target Register

    srlx %g1, TSB_TAG_TARGET_CONTEXT_SHIFT, %g2 ! is this a kernel miss?

    brz,pn %g2, 0f

    ldxa [%g0] ASI_DMMU_TSB_8KB_PTR_REG, %g3    ! read TSB 8K Pointer

    ldda [%g3] ASI_NUCLEUS_QUAD_LDD, %g4        ! 16-byte atomic load into %g4 and %g5

    cmp %g1, %g4                    ! is this the entry we are looking for?

    bne,pn %xcc, 0f

    nop

    stxa %g5, [%g0] ASI_DTLB_DATA_IN_REG        ! copy mapping from DTSB to DTLB

    retry

#endif

    /*

     * Second, test if it is the portion of the kernel address space

     * which is faulting. If that is the case, immediately create

     * identity mapping for that page in DTLB. VPN 0 is excluded from

     * this treatment.

     *

     * Note that branch-delay slots are used in order to save space.

     */

0:

    mov VA_DMMU_TAG_ACCESS, %g1

    ldxa [%g1] ASI_DMMU, %g1            ! read the faulting Context and VPN

    set TLB_TAG_ACCESS_CONTEXT_MASK, %g2

    andcc %g1, %g2, %g3             ! get Context

    bnz 0f                      ! Context is non-zero

    andncc %g1, %g2, %g3                ! get page address into %g3

    bz 0f                       ! page address is zero

    sethi %hi(kernel_8k_tlb_data_template), %g2

    ldx [%g2 + %lo(kernel_8k_tlb_data_template)], %g2

    or %g3, %g2, %g2

    stxa %g2, [%g0] ASI_DTLB_DATA_IN_REG        ! identity map the kernel page

    retry

    /*

     * Third, catch and handle special cases when the trap is caused by

     * the userspace register window spill or fill handler. In case

     * one of these two traps caused this trap, we just lower the trap

     * level and service the DTLB miss. In the end, we restart

     * the offending SAVE or RESTORE.

     */

0:

.if (\tl > 0)

    wrpr %g0, 1, %tl

.endif

    /*

     * Switch from the MM globals.

     */

    wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate

    /*

     * Read the Tag Access register for the higher-level handler.

     * This is necessary to survive nested DTLB misses.

     */

    mov VA_DMMU_TAG_ACCESS, %g2

    ldxa [%g2] ASI_DMMU, %g2

    /*

     * g2 will be passed as an argument to fast_data_access_mmu_miss().

     */

    PREEMPTIBLE_HANDLER fast_data_access_mmu_miss

.endm

.macro FAST_DATA_ACCESS_PROTECTION_HANDLER tl

    /*

     * The same special case as in FAST_DATA_ACCESS_MMU_MISS_HANDLER.

     */

.if (\tl > 0)

    wrpr %g0, 1, %tl

.endif

    /*

     * Switch from the MM globals.

     */

    wrpr %g0, PSTATE_PRIV_BIT | PSTATE_AG_BIT, %pstate

    /*

     * Read the Tag Access register for the higher-level handler.

     * This is necessary to survive nested DTLB misses.

     */

    mov VA_DMMU_TAG_ACCESS, %g2

    ldxa [%g2] ASI_DMMU, %g2

    /*

     * g2 will be passed as an argument to fast_data_access_mmu_miss().

     */

    PREEMPTIBLE_HANDLER fast_data_access_protection

.endm

#endif /* __ASM__ */

#endif

/** @}

 */