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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.
 */

#include <genarch/mm/page_pt.h>
#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>

static void pt_mapping_insert(__address page, __address frame, int flags, __address root);
static pte_t *pt_mapping_find(__address page, __address root);

page_operations_t page_pt_operations = {
    .mapping_insert = pt_mapping_insert,
    .mapping_find = pt_mapping_find
};

/** Map page to frame using hierarchical page tables.
 *
 * Map virtual address 'page' to physical address 'frame'
 * using 'flags'.
 *
 * @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 pt_mapping_insert(__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, ONE_FRAME);
        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 | PAGE_CACHEABLE | PAGE_WRITE);
    }

    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, ONE_FRAME);
        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 | PAGE_CACHEABLE | PAGE_WRITE);
    }

    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, ONE_FRAME);
        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 | PAGE_CACHEABLE | PAGE_WRITE);
    }

    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 in hierarchical page tables.
 *
 * 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 *pt_mapping_find(__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)];
}