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/*

 * Copyright (C) 2001-2004 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.

 */

#include <mm/page.h>

#include <mm/frame.h>

#include <arch/mm/page.h>

#include <arch/types.h>

#include <typedefs.h>

#include <arch/asm.h>

#include <memstr.h>

void page_init(void)

{

    page_arch_init();

    map_page_to_frame(0x0, 0x0, PAGE_NOT_PRESENT, 0);

}

/** Map memory structure

 *

 * Identity-map memory structure

 * considering possible crossings

 * of page boundaries.

 *

 * @param s Address of the structure.

 * @param size Size of the structure.

 */

void map_structure(__address s, size_t size)

{

    int i, cnt, length;

    length = size + (s - (s & ~(PAGE_SIZE-1)));

    cnt = length/PAGE_SIZE + (length%PAGE_SIZE>0);

    for (i = 0; i < cnt; i++)

        map_page_to_frame(s + i*PAGE_SIZE, s + i*PAGE_SIZE, PAGE_NOT_CACHEABLE, 0);

}

/** Map page to frame

 *

 * Map virtual address 'page' to physical address 'frame'

 * using 'flags'. Allocate and setup any missing page tables.

 *

 * @param page Virtual address of the page to be mapped.

 * @param frame Physical address of memory frame to which the mapping is done.

 * @param flags Flags to be used for mapping.

 * @param root Explicit PTL0 address.

 */

void map_page_to_frame(__address page, __address frame, int flags, __address root)

{

    pte_t *ptl0, *ptl1, *ptl2, *ptl3;

    __address newpt;

    ptl0 = (pte_t *) PA2KA(root ? root : (__address) GET_PTL0_ADDRESS());

    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {

        newpt = frame_alloc(FRAME_KA);

        memsetb(newpt, PAGE_SIZE, 0);

        SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));

        SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC);

    }

    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));

    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {

        newpt = frame_alloc(FRAME_KA);

        memsetb(newpt, PAGE_SIZE, 0);

        SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));

        SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC);

    }

    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));

    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {

        newpt = frame_alloc(FRAME_KA);

        memsetb(newpt, PAGE_SIZE, 0);

        SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));

        SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC);

    }

    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));

    SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);

    SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags);

}

/** Find mapping for virtual page

 *

 * Find mapping for virtual page.

 *

 * @param page Virtual page.

 * @param root PTL0 address if non-zero.

 *

 * @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise.

 */

pte_t *find_mapping(__address page, __address root)

{

    pte_t *ptl0, *ptl1, *ptl2, *ptl3;

    ptl0 = (pte_t *) PA2KA(root ? root : (__address) GET_PTL0_ADDRESS());

    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)

        return NULL;

    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));

    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)

        return NULL;

    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));

    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)

        return NULL;

    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));

    return &ptl3[PTL3_INDEX(page)];

}