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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.

 */

/*

 * TLB management.

 */

#include <mm/tlb.h>

#include <mm/asid.h>

#include <mm/page.h>

#include <mm/as.h>

#include <arch/mm/tlb.h>

#include <arch/mm/page.h>

#include <arch/barrier.h>

#include <arch/interrupt.h>

#include <typedefs.h>

#include <panic.h>

#include <arch.h>

/** Invalidate all TLB entries. */

void tlb_invalidate_all(void)

{

    /* TODO */

}

/** Invalidate entries belonging to an address space.

 *

 * @param asid Address space identifier.

 */

void tlb_invalidate_asid(asid_t asid)

{

    /* TODO */

}

/** Insert data into data translation cache.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 */

void dtc_mapping_insert(__address va, asid_t asid, tlb_entry_t entry) {

    tc_mapping_insert(va, asid, entry, true);

}

/** Insert data into instruction translation cache.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 */

void itc_mapping_insert(__address va, asid_t asid, tlb_entry_t entry) {

    tc_mapping_insert(va, asid, entry, false);

}

/** Insert data into instruction or data translation cache.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 * @param dtc If true, insert into data translation cache, use instruction translation cache otherwise.

 */

void tc_mapping_insert(__address va, asid_t asid, tlb_entry_t entry, bool dtc)

{

    region_register rr;

    bool restore_rr = false;

    rr.word = rr_read(VA2VRN(va));

    if ((restore_rr = (rr.map.rid != ASID2RID(asid, VA2VRN(va))))) {

        /*

         * The selected region register does not contain required RID.

         * Save the old content of the register and replace the RID.

         */

        region_register rr0;

        rr0 = rr;

        rr0.map.rid = ASID2RID(asid, VA2VRN(va));

        rr_write(VA2VRN(va), rr0.word);

        srlz_d();

        srlz_i();

    }

    __asm__ volatile (

        "mov r8=psr;;\n"

        "rsm %0;;\n"            /* PSR_IC_MASK */

        "srlz.d;;\n"

        "srlz.i;;\n"

        "mov cr.ifa=%1\n"       /* va */

        "mov cr.itir=%2;;\n"        /* entry.word[1] */

        "cmp.eq p6,p7 = %4,r0;;\n"  /* decide between itc and dtc */

        "(p6) itc.i %3;;\n"

        "(p7) itc.d %3;;\n"

        "mov psr.l=r8;;\n"

        "srlz.d;;\n"

        :

        : "i" (PSR_IC_MASK), "r" (va), "r" (entry.word[1]), "r" (entry.word[0]), "r" (dtc)

        : "p6", "p7", "r8"

    );

    if (restore_rr) {

        rr_write(VA2VRN(va), rr.word);

        srlz_d();

        srlz_i();

    }

}

/** Insert data into instruction translation register.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 * @param tr Translation register.

 */

void itr_mapping_insert(__address va, asid_t asid, tlb_entry_t entry, index_t tr)

{

    tr_mapping_insert(va, asid, entry, false, tr);

}

/** Insert data into data translation register.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 * @param tr Translation register.

 */

void dtr_mapping_insert(__address va, asid_t asid, tlb_entry_t entry, index_t tr)

{

    tr_mapping_insert(va, asid, entry, true, tr);

}

/** Insert data into instruction or data translation register.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 * @param dtc If true, insert into data translation register, use instruction translation register otherwise.

 * @param tr Translation register.

 */

void tr_mapping_insert(__address va, asid_t asid, tlb_entry_t entry, bool dtr, index_t tr)

{

    region_register rr;

    bool restore_rr = false;

    rr.word = rr_read(VA2VRN(va));

    if ((restore_rr = (rr.map.rid != ASID2RID(asid, VA2VRN(va))))) {

        /*

         * The selected region register does not contain required RID.

         * Save the old content of the register and replace the RID.

         */

        region_register rr0;

        rr0 = rr;

        rr0.map.rid = ASID2RID(asid, VA2VRN(va));

        rr_write(VA2VRN(va), rr0.word);

        srlz_d();

        srlz_i();

    }

    __asm__ volatile (

        "mov r8=psr;;\n"

        "rsm %0;;\n"            /* PSR_IC_MASK */

        "srlz.d;;\n"

        "srlz.i;;\n"

        "mov cr.ifa=%1\n"           /* va */         

        "mov cr.itir=%2;;\n"        /* entry.word[1] */

        "cmp.eq p6,p7=%5,r0;;\n"    /* decide between itr and dtr */

        "(p6) itr.i itr[%4]=%3;;\n"

        "(p7) itr.d dtr[%4]=%3;;\n"

        "mov psr.l=r8;;\n"

        "srlz.d;;\n"

        :

        : "i" (PSR_IC_MASK), "r" (va), "r" (entry.word[1]), "r" (entry.word[0]), "r" (tr), "r" (dtr)

        : "p6", "p7", "r8"

    );

    if (restore_rr) {

        rr_write(VA2VRN(va), rr.word);

        srlz_d();

        srlz_i();

    }

}

/** Insert data into DTLB.

 *

 * @param va Virtual page address.

 * @param asid Address space identifier.

 * @param entry The rest of TLB entry as required by TLB insertion format.

 * @param dtr If true, insert into data translation register, use data translation cache otherwise.

 * @param tr Translation register if dtr is true, ignored otherwise.

 */

void dtlb_kernel_mapping_insert(__address page, __address frame, bool dtr, index_t tr)

{

    tlb_entry_t entry;

    entry.word[0] = 0;

    entry.word[1] = 0;

    entry.p = true;         /* present */

    entry.ma = MA_WRITEBACK;

    entry.a = true;         /* already accessed */

    entry.d = true;         /* already dirty */

    entry.pl = PL_KERNEL;

    entry.ar = AR_READ | AR_WRITE;

    entry.ppn = frame >> PPN_SHIFT;

    entry.ps = PAGE_WIDTH;

    if (dtr)

        dtr_mapping_insert(page, ASID_KERNEL, entry, tr);

    else

        dtc_mapping_insert(page, ASID_KERNEL, entry);

}

/** Copy content of PTE into data translation cache.

 *

 * @param t PTE.

 */

void dtc_pte_copy(pte_t *t)

{

    tlb_entry_t entry;

    entry.word[0] = 0;

    entry.word[1] = 0;

    entry.p = t->p;

    entry.ma = t->c ? MA_WRITEBACK : MA_UNCACHEABLE;

    entry.a = t->a;

    entry.d = t->d;

    entry.pl = t->k ? PL_KERNEL : PL_USER;

    entry.ar = t->w ? AR_WRITE : AR_READ;

    entry.ppn = t->frame >> PPN_SHIFT;

    entry.ps = PAGE_WIDTH;

    dtc_mapping_insert(t->page, t->as->asid, entry);

}

/** Copy content of PTE into instruction translation cache.

 *

 * @param t PTE.

 */

void itc_pte_copy(pte_t *t)

{

    tlb_entry_t entry;

    entry.word[0] = 0;

    entry.word[1] = 0;

    ASSERT(t->x);

    entry.p = t->p;

    entry.ma = t->c ? MA_WRITEBACK : MA_UNCACHEABLE;

    entry.a = t->a;

    entry.pl = t->k ? PL_KERNEL : PL_USER;

    entry.ar = t->x ? (AR_EXECUTE | AR_READ) : AR_READ;

    entry.ppn = t->frame >> PPN_SHIFT;

    entry.ps = PAGE_WIDTH;

    itc_mapping_insert(t->page, t->as->asid, entry);

}

/** Instruction TLB fault handler for faults with VHPT turned off.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void alternate_instruction_tlb_fault(__u64 vector, struct exception_regdump *pstate)

{

    region_register rr;

    __address va;

    pte_t *t;

    va = pstate->cr_ifa;    /* faulting address */

    t = page_mapping_find(AS, va);

    if (t) {

        /*

         * The mapping was found in software page hash table.

         * Insert it into data translation cache.

         */

        itc_pte_copy(t);

    } else {

        /*

         * Forward the page fault to address space page fault handler.

         */

        if (!as_page_fault(va)) {

            panic("%s: va=%P, rid=%d\n", __FUNCTION__, pstate->cr_ifa, rr.map.rid);

        }

    }

}

/** Data TLB fault handler for faults with VHPT turned off.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void alternate_data_tlb_fault(__u64 vector, struct exception_regdump *pstate)

{

    region_register rr;

    rid_t rid;

    __address va;

    pte_t *t;

    va = pstate->cr_ifa;    /* faulting address */

    rr.word = rr_read(VA2VRN(va));

    rid = rr.map.rid;

    if (RID2ASID(rid) == ASID_KERNEL) {

        if (VA2VRN(va) == VRN_KERNEL) {

            /*

             * Provide KA2PA(identity) mapping for faulting piece of

             * kernel address space.

             */

            dtlb_kernel_mapping_insert(va, KA2PA(va), false, 0);

            return;

        }

    }

    t = page_mapping_find(AS, va);

    if (t) {

        /*

         * The mapping was found in software page hash table.

         * Insert it into data translation cache.

         */

        dtc_pte_copy(t);

    } else {

        /*

         * Forward the page fault to address space page fault handler.

         */

        if (!as_page_fault(va)) {

            panic("%s: va=%P, rid=%d\n", __FUNCTION__, pstate->cr_ifa, rr.map.rid);

        }

    }

}

/** Data nested TLB fault handler.

 *

 * This fault should not occur.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void data_nested_tlb_fault(__u64 vector, struct exception_regdump *pstate)

{

    panic("%s\n", __FUNCTION__);

}

/** Data Dirty bit fault handler.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void data_dirty_bit_fault(__u64 vector, struct exception_regdump *pstate)

{

    pte_t *t;

    t = page_mapping_find(AS, pstate->cr_ifa);

    ASSERT(t && t->p);

    if (t && t->p) {

        /*

         * Update the Dirty bit in page tables and reinsert

         * the mapping into DTC.

         */

        t->d = true;

        dtc_pte_copy(t);

    }

}

/** Instruction access bit fault handler.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void instruction_access_bit_fault(__u64 vector, struct exception_regdump *pstate)

{

    pte_t *t;

    t = page_mapping_find(AS, pstate->cr_ifa);

    ASSERT(t && t->p);

    if (t && t->p) {

        /*

         * Update the Accessed bit in page tables and reinsert

         * the mapping into ITC.

         */

        t->a = true;

        itc_pte_copy(t);

    }

}

/** Data access bit fault handler.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void data_access_bit_fault(__u64 vector, struct exception_regdump *pstate)

{

    pte_t *t;

    t = page_mapping_find(AS, pstate->cr_ifa);

    ASSERT(t && t->p);

    if (t && t->p) {

        /*

         * Update the Accessed bit in page tables and reinsert

         * the mapping into DTC.

         */

        t->a = true;

        dtc_pte_copy(t);

    }

}

/** Page not present fault handler.

 *

 * @param vector Interruption vector.

 * @param pstate Structure with saved interruption state.

 */

void page_not_present(__u64 vector, struct exception_regdump *pstate)

{

    region_register rr;

    __address va;

    pte_t *t;

    va = pstate->cr_ifa;    /* faulting address */

    t = page_mapping_find(AS, va);

    ASSERT(t);

    if (t->p) {

        /*

         * If the Present bit is set in page hash table, just copy it

         * and update ITC/DTC.

         */

        if (t->x)

            itc_pte_copy(t);

        else

            dtc_pte_copy(t);

    } else {

        if (!as_page_fault(va)) {

            panic("%s: va=%P, rid=%d\n", __FUNCTION__, pstate->cr_ifa, rr.map.rid);

        }

    }

}