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684 jermar 1
/*
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 * Copyright (C) 2006 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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#include <genarch/mm/page_pt.h>
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#include <mm/page.h>
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#include <mm/frame.h>
756 jermar 32
#include <mm/as.h>
684 jermar 33
#include <arch/mm/page.h>
755 jermar 34
#include <arch/mm/as.h>
684 jermar 35
#include <arch/types.h>
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#include <typedefs.h>
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#include <arch/asm.h>
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#include <memstr.h>
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756 jermar 40
static void pt_mapping_insert(as_t *as, __address page, __address frame, int flags);
826 jermar 41
static void pt_mapping_remove(as_t *as, __address page);
756 jermar 42
static pte_t *pt_mapping_find(as_t *as, __address page);
684 jermar 43
 
793 jermar 44
page_mapping_operations_t pt_mapping_operations = {
684 jermar 45
    .mapping_insert = pt_mapping_insert,
826 jermar 46
    .mapping_remove = pt_mapping_remove,
684 jermar 47
    .mapping_find = pt_mapping_find
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};
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/** Map page to frame using hierarchical page tables.
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 *
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 * Map virtual address 'page' to physical address 'frame'
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 * using 'flags'.
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 *
756 jermar 55
 * The address space must be locked and interrupts must be disabled.
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 *
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 * @param as Address space to wich page belongs.
684 jermar 58
 * @param page Virtual address of the page to be mapped.
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 * @param frame Physical address of memory frame to which the mapping is done.
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 * @param flags Flags to be used for mapping.
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 */
756 jermar 62
void pt_mapping_insert(as_t *as, __address page, __address frame, int flags)
684 jermar 63
{
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    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
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    __address newpt;
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756 jermar 67
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
684 jermar 68
 
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    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
814 palkovsky 70
        newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
684 jermar 71
        memsetb(newpt, PAGE_SIZE, 0);
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        SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
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        SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
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    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
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    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
814 palkovsky 79
        newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
684 jermar 80
        memsetb(newpt, PAGE_SIZE, 0);
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        SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
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        SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
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    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
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    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {
814 palkovsky 88
        newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
684 jermar 89
        memsetb(newpt, PAGE_SIZE, 0);
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        SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
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        SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
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    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
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    SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);
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    SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags);
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}
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826 jermar 100
/** Remove mapping of page from hierarchical page tables.
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 *
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 * Remove any mapping of 'page' within address space 'as'.
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 * TLB shootdown should follow in order to make effects of
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 * this call visible.
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 *
832 jermar 106
 * Empty page tables except PTL0 are freed.
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 *
826 jermar 108
 * The address space must be locked and interrupts must be disabled.
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 *
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 * @param as Address space to wich page belongs.
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 * @param page Virtual address of the page to be demapped.
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 */
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void pt_mapping_remove(as_t *as, __address page)
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{
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    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
832 jermar 116
    bool empty = true;
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    int i;
826 jermar 118
 
832 jermar 119
    /*
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     * First, remove the mapping, if it exists.
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     */
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826 jermar 123
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
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125
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
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        return;
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128
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
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130
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
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        return;
132
 
133
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
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135
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
136
        return;
137
 
138
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
139
 
140
    /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */
141
    memsetb((__address) &ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
832 jermar 142
 
143
    /*
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     * Second, free all empty tables along the way from PTL3 down to PTL0.
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     */
146
 
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    /* check PTL3 */
148
    for (i = 0; i < PTL3_ENTRIES; i++) {
149
        if (PTE_VALID(&ptl3[i])) {
150
            empty = false;
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            break;
152
        }
153
    }
154
    if (empty) {
155
        /*
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         * PTL3 is empty.
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         * Release the frame and remove PTL3 pointer from preceding table.
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         */
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        frame_free(ADDR2PFN(KA2PA((__address) ptl3)));
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        if (PTL2_ENTRIES)
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            memsetb((__address) &ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
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        else if (PTL1_ENTRIES)
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            memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
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        else
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            memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
166
    } else {
167
        /*
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         * PTL3 is not empty.
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         * Therefore, there must be a path from PTL0 to PTL3 and
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         * thus nothing to free in higher levels.
171
         */
172
        return;
173
    }
174
 
175
    /* check PTL2, empty is still true */
176
    if (PTL2_ENTRIES) {
177
        for (i = 0; i < PTL2_ENTRIES; i++) {
178
            if (PTE_VALID(&ptl2[i])) {
179
                empty = false;
180
                break;
181
            }
182
        }
183
        if (empty) {
184
            /*
185
             * PTL2 is empty.
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             * Release the frame and remove PTL2 pointer from preceding table.
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             */
188
            frame_free(ADDR2PFN(KA2PA((__address) ptl2)));
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            if (PTL1_ENTRIES)
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                memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
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            else
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                memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
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        }
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        else {
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            /*
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             * PTL2 is not empty.
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             * Therefore, there must be a path from PTL0 to PTL2 and
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             * thus nothing to free in higher levels.
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             */
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            return;
201
        }
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    }
203
 
204
    /* check PTL1, empty is still true */
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    if (PTL1_ENTRIES) {
206
        for (i = 0; i < PTL1_ENTRIES; i++) {
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            if (PTE_VALID(&ptl1[i])) {
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                empty = false;
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                break;
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            }
211
        }
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        if (empty) {
213
            /*
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             * PTL1 is empty.
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             * Release the frame and remove PTL1 pointer from preceding table.
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             */
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            frame_free(ADDR2PFN(KA2PA((__address) ptl1)));
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            memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
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        }
220
    }
221
 
826 jermar 222
}
223
 
684 jermar 224
/** Find mapping for virtual page in hierarchical page tables.
225
 *
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 * Find mapping for virtual page.
227
 *
756 jermar 228
 * The address space must be locked and interrupts must be disabled.
229
 *
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 * @param as Address space to which page belongs.
684 jermar 231
 * @param page Virtual page.
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 *
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 * @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise.
234
 */
756 jermar 235
pte_t *pt_mapping_find(as_t *as, __address page)
684 jermar 236
{
237
    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
238
 
756 jermar 239
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
684 jermar 240
 
241
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
242
        return NULL;
243
 
244
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
245
 
246
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
247
        return NULL;
248
 
249
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
250
 
251
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
252
        return NULL;
253
 
254
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
255
 
256
    return &ptl3[PTL3_INDEX(page)];
257
}