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/*

 * Copyright (c) 2006 Jakub Jermar

 * Copyright (c) 2008 Pavel Rimsky

 * 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_sun4v_MMU_TRAP_H_

#define KERN_sparc64_sun4v_MMU_TRAP_H_

#include <arch/stack.h>

#include <arch/regdef.h>

#include <arch/arch.h>

#include <arch/sun4v/hypercall.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__

/* MMU fault status area data fault offset */

#define FSA_DFA_OFFSET              0x48

/* MMU fault status area data context */

#define FSA_DFC_OFFSET              0x50

/* offset of the target address within the TTE Data entry */

#define TTE_DATA_TADDR_OFFSET           13

.macro FAST_INSTRUCTION_ACCESS_MMU_MISS_HANDLER

    PREEMPTIBLE_HANDLER fast_instruction_access_mmu_miss

.endm

/*

 * Handler of the Fast Data Access MMU Miss trap. If the trap occurred in the kernel

 * (context 0), an identity mapping (with displacement) is installed. Otherwise

 * a higher level service routine is called.

 */

.macro FAST_DATA_ACCESS_MMU_MISS_HANDLER tl

    mov SCRATCHPAD_MMU_FSA, %g1

    ldxa [%g1] ASI_SCRATCHPAD, %g1          ! g1 <= RA of MMU fault status area

    /* read faulting context */

    add %g1, FSA_DFC_OFFSET, %g2            ! g2 <= RA of data fault context

    ldxa [%g2] ASI_REAL, %g3            ! read the fault context

    /* read the faulting address */

    add %g1, FSA_DFA_OFFSET, %g2            ! g2 <= RA of data fault address

    ldxa [%g2] ASI_REAL, %g1            ! read the fault address

    srlx %g1, TTE_DATA_TADDR_OFFSET, %g1        ! truncate it to page boundary

    sllx %g1, TTE_DATA_TADDR_OFFSET, %g1

    /* service by higher-level routine when context != 0 */

    brnz %g3, 0f

    nop

    /* exclude page number 0 from installing the identity mapping */

    brz %g1, 0f

    nop

    /*

     * Installing the identity does not fit into 32 instructions, call

     * a separate routine. The routine performs RETRY, hence the call never

     * returns.

     */

    ba install_identity_mapping

    nop

    0:

    /*

     * One of the scenarios in which this trap can occur is when the

     * register window spill/fill handler accesses a memory which is not

     * mapped. In such a case, this handler will be called from TL = 1.

     * We handle the situation by pretending that the MMU miss occurred

     * on TL = 0. Once the MMU miss trap is services, the instruction which

     * caused the spill/fill trap is restarted, the spill/fill trap occurs,

     * but this time its handler accesse memory which IS mapped.

     */

    .if (\tl > 0)

        wrpr %g0, 1, %tl

    .endif

    /*

     * Save the faulting virtual page and faulting context to the %g2

     * register. The most significant 51 bits of the %g2 register will

     * contain the virtual address which caused the fault truncated to the

     * page boundary. The least significant 13 bits of the %g2 register

     * will contain the number of the context in which the fault occurred.

     * The value of the %g2 register will be passed as a parameter to the

     * higher level service routine.

     */

    or %g1, %g3, %g2

    PREEMPTIBLE_HANDLER fast_data_access_mmu_miss

.endm

/*

 * Handler of the Fast Data MMU Protection trap. Finds the trapping address

 * and context and calls higher level service routine.

 */

.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

    mov SCRATCHPAD_MMU_FSA, %g1

    ldxa [%g1] ASI_SCRATCHPAD, %g1          ! g1 <= RA of MMU fault status area

    /* read faulting context */

    add %g1, FSA_DFC_OFFSET, %g2            ! g2 <= RA of data fault context

    ldxa [%g2] ASI_REAL, %g3            ! read the fault context

    /* read the faulting address */

    add %g1, FSA_DFA_OFFSET, %g2            ! g2 <= RA of data fault address

    ldxa [%g2] ASI_REAL, %g1            ! read the fault address

    srlx %g1, TTE_DATA_TADDR_OFFSET, %g1        ! truncate it to page boundary

    sllx %g1, TTE_DATA_TADDR_OFFSET, %g1

    /* the same as for FAST_DATA_ACCESS_MMU_MISS_HANDLER */

    or %g1, %g3, %g2

    PREEMPTIBLE_HANDLER fast_data_access_protection

.endm

#endif /* __ASM__ */

#endif

/** @}

 */