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/*

 * Copyright (C) 2006 Jakub Jermar

 * Copyright (C) 2006 Jakub Vana

 * 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.

 */

#include <arch/mm/page.h>

#include <genarch/mm/page_ht.h>

#include <mm/asid.h>

#include <arch/mm/asid.h>

#include <arch/types.h>

#include <typedefs.h>

#include <print.h>

#include <mm/page.h>

#include <mm/frame.h>

#include <config.h>

#include <panic.h>

#include <arch/asm.h>

#include <arch/barrier.h>

#include <memstr.h>

static void set_vhpt_environment(void);

/** Initialize ia64 virtual address translation subsystem. */

void page_arch_init(void)

{

    page_operations = &page_ht_operations;

    pk_disable();

    set_vhpt_environment();

}

/** Initialize VHPT and region registers. */

void set_vhpt_environment(void)

{

    region_register rr;

    pta_register pta;  

    int i;

    /*

     * First set up kernel region register.

     */

    rr.word = rr_read(VRN_KERNEL);

    rr.map.ve = 0;                  /* disable VHPT walker */

    rr.map.ps = PAGE_WIDTH;

    rr.map.rid = ASID_KERNEL;

    rr_write(VRN_KERNEL, rr.word);

    srlz_i();

    srlz_d();

    /*

     * And invalidate the rest of region register.

     */

    for(i = 0; i < REGION_REGISTERS; i++) {

        /* skip kernel rr */

        if (i == VRN_KERNEL)

            continue;

        rr.word == rr_read(i);

        rr.map.ve = 0;      /* disable VHPT walker */

        rr.map.rid = ASID_INVALID;

        rr_write(i, rr.word);

        srlz_i();

        srlz_d();

    }

    /*

     * Allocate VHPT and invalidate all its entries.

     */

    page_ht = (pte_t *) frame_alloc(FRAME_KA, VHPT_WIDTH - FRAME_WIDTH, NULL);

    memsetb((__address) page_ht, VHPT_SIZE, 0);

    ht_invalidate_all();   

    /*

     * Set up PTA register.

     */

    pta.word = pta_read();

    pta.map.ve = 0;                   /* disable VHPT walker */

    pta.map.vf = 1;                   /* large entry format */

    pta.map.size = VHPT_WIDTH;

    pta.map.base = ((__address) page_ht) >> PTA_BASE_SHIFT;

    pta_write(pta.word);

    srlz_i();

    srlz_d();

}

/** Calculate address of collision chain from VPN and ASID.

 *

 * Interrupts must be disabled.

 *

 * @param page Address of virtual page including VRN bits.

 * @param asid Address space identifier.

 *

 * @return Head of VHPT collision chain for page and asid.

 */

pte_t *vhpt_hash(__address page, asid_t asid)

{

    region_register rr_save, rr;

    index_t vrn;

    rid_t rid;

    pte_t *t;

    vrn = page >> VRN_SHIFT;

    rid = ASID2RID(asid, vrn);

    rr_save.word = rr_read(vrn);

    if (rr_save.map.rid == rid) {

        /*

         * The RID is already in place, compute thash and return.

         */

        t = (pte_t *) thash(page);

        return t;

    }

    /*

     * The RID must be written to some region register.

     * To speed things up, register indexed by vrn is used.

     */

    rr.word = rr_save.word;

    rr.map.rid = rid;

    rr_write(vrn, rr.word);

    srlz_i();

    t = (pte_t *) thash(page);

    rr_write(vrn, rr_save.word);

    srlz_i();

    srlz_d();

    return t;

}

/** Compare ASID and VPN against PTE.

 *

 * Interrupts must be disabled.

 *

 * @param page Address of virtual page including VRN bits.

 * @param asid Address space identifier.

 *

 * @return True if page and asid match the page and asid of t, false otherwise.

 */

bool vhpt_compare(__address page, asid_t asid, pte_t *t)

{

    region_register rr_save, rr;   

    index_t vrn;

    rid_t rid;

    bool match;

    ASSERT(t);

    vrn = page >> VRN_SHIFT;

    rid = ASID2RID(asid, vrn);

    rr_save.word = rr_read(vrn);

    if (rr_save.map.rid == rid) {

        /*

         * The RID is already in place, compare ttag with t and return.

         */

        return ttag(page) == t->present.tag.tag_word;

    }

    /*

     * The RID must be written to some region register.

     * To speed things up, register indexed by vrn is used.

     */

    rr.word = rr_save.word;

    rr.map.rid = rid;

    rr_write(vrn, rr.word);

    srlz_i();

    match = (ttag(page) == t->present.tag.tag_word);

    rr_write(vrn, rr_save.word);

    srlz_i();

    srlz_d();

    return match;      

}

/** Set up one VHPT entry.

 *

 * @param t VHPT entry to be set up.

 * @param page Virtual address of the page mapped by the entry.

 * @param asid Address space identifier of the address space to which page belongs.

 * @param frame Physical address of the frame to wich page is mapped.

 * @param flags Different flags for the mapping.

 */

void vhpt_set_record(pte_t *t, __address page, asid_t asid, __address frame, int flags)

{

    region_register rr_save, rr;   

    index_t vrn;

    rid_t rid;

    __u64 tag;

    ASSERT(t);

    vrn = page >> VRN_SHIFT;

    rid = ASID2RID(asid, vrn);

    /*

     * Compute ttag.

     */

    rr_save.word = rr_read(vrn);

    rr.word = rr_save.word;

    rr.map.rid = rid;

    rr_write(vrn, rr.word);

    srlz_i();

    tag = ttag(page);

    rr_write(vrn, rr_save.word);

    srlz_i();

    srlz_d();

    /*

     * Clear the entry.

     */

    t->word[0] = 0;

    t->word[1] = 0;

    t->word[2] = 0;

    t->word[3] = 0;

    t->present.p = true;

    t->present.ma = (flags & PAGE_CACHEABLE) ? MA_WRITEBACK : MA_UNCACHEABLE;

    t->present.a = false;   /* not accessed */

    t->present.d = false;   /* not dirty */

    t->present.pl = (flags & PAGE_USER) ? PL_USER : PL_KERNEL;

    t->present.ar = (flags & PAGE_WRITE) ? AR_WRITE : AR_READ;

    t->present.ar |= (flags & PAGE_EXEC) ? AR_EXECUTE : 0;

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

    t->present.ed = false;  /* exception not deffered */

    t->present.ps = PAGE_WIDTH;

    t->present.key = 0;

    t->present.tag.tag_word = tag;

    t->present.next = NULL;

}