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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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1702 cejka 29
 /** @addtogroup genarchmm
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 * @{
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 */
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1266 jermar 33
/**
1702 cejka 34
 * @file
1266 jermar 35
 * @brief   Virtual Address Translation for hierarchical 4-level page tables.
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 */
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684 jermar 38
#include <genarch/mm/page_pt.h>
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#include <mm/page.h>
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#include <mm/frame.h>
756 jermar 41
#include <mm/as.h>
684 jermar 42
#include <arch/mm/page.h>
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#include <arch/mm/as.h>
684 jermar 44
#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 49
static void pt_mapping_insert(as_t *as, __address page, __address frame, int flags);
826 jermar 50
static void pt_mapping_remove(as_t *as, __address page);
756 jermar 51
static pte_t *pt_mapping_find(as_t *as, __address page);
684 jermar 52
 
793 jermar 53
page_mapping_operations_t pt_mapping_operations = {
684 jermar 54
    .mapping_insert = pt_mapping_insert,
826 jermar 55
    .mapping_remove = pt_mapping_remove,
684 jermar 56
    .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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 *
1248 jermar 61
 * Map virtual address page to physical address frame
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 * using flags.
684 jermar 63
 *
1044 jermar 64
 * The page table must be locked and interrupts must be disabled.
756 jermar 65
 *
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 * @param as Address space to wich page belongs.
684 jermar 67
 * @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 71
void pt_mapping_insert(as_t *as, __address page, __address frame, int flags)
684 jermar 72
{
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    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
1760 palkovsky 74
    pte_t *newpt;
684 jermar 75
 
756 jermar 76
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
684 jermar 77
 
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    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
1760 palkovsky 79
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
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        memsetb((__address)newpt, PAGE_SIZE, 0);
684 jermar 81
        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) {
1760 palkovsky 88
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
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        memsetb((__address)newpt, PAGE_SIZE, 0);
684 jermar 90
        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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94
    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) {
1760 palkovsky 97
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
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        memsetb((__address)newpt, PAGE_SIZE, 0);
684 jermar 99
        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 109
/** Remove mapping of page from hierarchical page tables.
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 *
1248 jermar 111
 * Remove any mapping of page within address space as.
826 jermar 112
 * TLB shootdown should follow in order to make effects of
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 * this call visible.
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 *
832 jermar 115
 * Empty page tables except PTL0 are freed.
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 *
1044 jermar 117
 * The page table must be locked and interrupts must be disabled.
826 jermar 118
 *
1248 jermar 119
 * @param as Address space to wich page belongs.
826 jermar 120
 * @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 125
    bool empty = true;
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    int i;
826 jermar 127
 
832 jermar 128
    /*
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     * First, remove the mapping, if it exists.
130
     */
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826 jermar 132
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
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134
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
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        return;
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137
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
138
 
139
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
140
        return;
141
 
142
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
143
 
144
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
145
        return;
146
 
147
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
148
 
149
    /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */
150
    memsetb((__address) &ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
832 jermar 151
 
152
    /*
153
     * Second, free all empty tables along the way from PTL3 down to PTL0.
154
     */
155
 
156
    /* check PTL3 */
157
    for (i = 0; i < PTL3_ENTRIES; i++) {
158
        if (PTE_VALID(&ptl3[i])) {
159
            empty = false;
160
            break;
161
        }
162
    }
163
    if (empty) {
164
        /*
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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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         */
1760 palkovsky 168
        frame_free(KA2PA((__address) ptl3));
832 jermar 169
        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);
175
    } else {
176
        /*
177
         * PTL3 is not empty.
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         * Therefore, there must be a path from PTL0 to PTL3 and
179
         * thus nothing to free in higher levels.
180
         */
181
        return;
182
    }
183
 
184
    /* check PTL2, empty is still true */
185
    if (PTL2_ENTRIES) {
186
        for (i = 0; i < PTL2_ENTRIES; i++) {
187
            if (PTE_VALID(&ptl2[i])) {
188
                empty = false;
189
                break;
190
            }
191
        }
192
        if (empty) {
193
            /*
194
             * PTL2 is empty.
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             * Release the frame and remove PTL2 pointer from preceding table.
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             */
1760 palkovsky 197
            frame_free(KA2PA((__address) ptl2));
832 jermar 198
            if (PTL1_ENTRIES)
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                memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
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            else
201
                memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
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        }
203
        else {
204
            /*
205
             * 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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             */
209
            return;
210
        }
211
    }
212
 
213
    /* check PTL1, empty is still true */
214
    if (PTL1_ENTRIES) {
215
        for (i = 0; i < PTL1_ENTRIES; i++) {
216
            if (PTE_VALID(&ptl1[i])) {
217
                empty = false;
218
                break;
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            }
220
        }
221
        if (empty) {
222
            /*
223
             * PTL1 is empty.
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             * Release the frame and remove PTL1 pointer from preceding table.
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             */
1760 palkovsky 226
            frame_free(KA2PA((__address) ptl1));
832 jermar 227
            memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
228
        }
229
    }
230
 
826 jermar 231
}
232
 
684 jermar 233
/** Find mapping for virtual page in hierarchical page tables.
234
 *
235
 * Find mapping for virtual page.
236
 *
1044 jermar 237
 * The page table must be locked and interrupts must be disabled.
756 jermar 238
 *
1248 jermar 239
 * @param as Address space to which page belongs.
684 jermar 240
 * @param page Virtual page.
241
 *
242
 * @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise.
243
 */
756 jermar 244
pte_t *pt_mapping_find(as_t *as, __address page)
684 jermar 245
{
246
    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
247
 
756 jermar 248
    ptl0 = (pte_t *) PA2KA((__address) as->page_table);
684 jermar 249
 
250
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
251
        return NULL;
252
 
253
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
254
 
255
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
256
        return NULL;
257
 
258
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
259
 
260
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
261
        return NULL;
262
 
263
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
264
 
265
    return &ptl3[PTL3_INDEX(page)];
266
}
1702 cejka 267
 
268
 /** @}
269
 */
270